Biochemical and Mineral Profiling of Two Recently Described Brachystelma Species from Northern Kerala India

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Thomas¹, Jeeshna M V This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8992980/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 10 You are reading this latest preprint version Abstract Wild edible tubers represent underutilized plant resources with potential nutritional significance. The present study evaluated the mineral composition, antinutritional factors, and predicted mineral bioavailability of tubers from two recently described species, Brachystelma ariyittaparensis and B. vartakii , collected from Northern Kerala, India. Mineral contents were determined using atomic absorption spectrophotometry and flame photometry following AOAC protocols, while antinutritional factors (phytate, oxalate, tannin, and alkaloids) were quantified using established biochemical methods. Significant interspecific variation in mineral profiles was observed (p < 0.05). B. vartakii exhibited higher concentrations of sodium, potassium, magnesium, phosphorus, and zinc, whereas B. ariyittaparensis contained comparatively higher levels of calcium, iron, and selenium. Antinutrient levels in both species were within ranges reported for commonly consumed tubers. Molar ratio analysis suggested favourable predicted bioavailability of key minerals. The findings highlight the biochemical potential of these underexplored geophytic species and provide baseline data relevant to their nutritional evaluation and future utilization. However, further studies on processing effects, safety assessment, and in vivo validation are recommended. Brachystelma endemic geophytes mineral profiling antinutritional factors wild edible plants plant nutritional traits Figures Figure 1 Figure 2 Figure 3 Figure 4 1. Introduction Most members of the genus Brachystelma R.Br. remain poorly studied in India due to their short life span, ephemeral growth habit, and the presence of subterranean storage organs such as bulbs, corms, tubers, or rhizomes. These species are predominantly distributed in the arid and semi-arid regions of the country. Their narrow seasonality and restricted distribution have resulted in their under-representation in early floristic accounts and herbarium records. Brachystelma R.Br. is the second largest genus in the tribe Ceropegieae of the subfamily Asclepiadoideae (Apocynaceae) and comprises approximately 160 species distributed mainly in the Old World tropics. The genus occurs in sub-Saharan Africa, India, Sri Lanka, Southeast Asia, and northern Australia [ 1 ]. Following recent taxonomic revision, the genus in India includes 38 taxa, of which 34 are native and 21 are endemic [ 2 ]. Despite this diversity, most species remain inadequately investigated because of their short life cycle, slow growth, and limited distribution. Moreover, their natural habitats are increasingly affected by anthropogenic pressures. Several members of Brachystelma have been reported to possess notable medicinal and nutritional attributes. The tubers of many species are traditionally consumed either raw or after processing by indigenous communities in Africa, Asia, and Australia [ 3 – 5 ]. Beyond their dietary use, these plants hold considerable ethnobotanical importance, particularly as emergency food resources in many regions. The tubers of Brachystelma species are characterized by high moisture and nutrient content, enhancing their potential as plant-based food resources. Owing to their high water content, nomadic communities and hunters in East Africa have traditionally used them to alleviate thirst in water-scarce environments. The tubers are also consumed by wild animals such as hedgehogs, moles, and blesmols and are generally regarded as non-toxic to humans and animals [ 6 ]. Numerous species within the genus have documented medicinal applications. For example, B. edulis , B. naorojii , and B. togoense have been reported to possess therapeutic properties for the treatment of stomach ache, headache, and wound healing [ 4 , 7 , 8 ]. Among the many species of Brachystelma , detailed nutritional information is currently available only for B. edulis and B. naorojii . Deshmukh and Rathod [ 4 ] reported that the tubers of B. edulis are rich in protein, fibre, and carbohydrates compared with common vegetables. Its carbohydrate content is comparable to that of African leafy vegetables such as gallwort, pigweed, and purslane. The fibre content of B. edulis (8%) is similar to that of Ceropegia hirsuta (9.1%), and both species exhibit comparable protein levels. While leaves and tubers show similar ash and moisture contents, the tubers possess higher dry matter content. These findings support the nutritional potential of Brachystelma species as supplementary plant resources. Further investigation of lesser-known Brachystelma species may expand their recognized utilization potential and support their inclusion in food and nutrition security programmes. However, despite the ethnobotanical importance of the genus, detailed information on mineral bioavailability and antinutritional interactions in recently described taxa from Northern Kerala remains scarce. Therefore, the present study aimed to evaluate the mineral composition, antinutritional factors, and predicted mineral bioavailability of tubers of Brachystelma ariyittaparensis and B. vartakii from Northern Kerala, India. 2. Materials and methods 2.1. Sample collection Fresh tubers of Brachystelma ariyittaparensi s (P.Biju,Josekutty & Augustine) K.Prasad & Venu and Brachystelma vartakii Kambale & S.R. Yadav were collected from natural populations in Northern Kerala, India, during the study period. The plant specimens were authenticated through morphological characteristics in accordance with standard floras. The geographical coordinates of the collection site are approximately 12.27°N, 75.13°E. Fresh tubers of the chosen species were collected, cleaned, and subjected to biochemical and mineral analysis.Voucher specimens were prepared and deposited in the Calicut University Herbarium (CALI) of the Department of Botany at University of Calicut, Kerala, India for future reference. The herbarium accession numbers are 7444 for Brachystelma ariyittaparensis and 7443 for Brachystelma vartakii respectively. 2.2.Determination of minerals content Approximately 3.0 g of each dried sample was carbonized on a heating plate and dry-ashed in a muffle furnace (Biotechnics India BTI-36) at 550°C until complete ashing was achieved. The resulting white ash was dissolved in 5 mL of 6 N HCl, evaporated to dryness on a hot plate, and further treated with 7 mL of 3 N HCl. The digest was finally diluted to 50 mL with de-ionized water for mineral analysis. Mineral contents were determined using an atomic absorption spectrophotometer (AAS) (Drawell DW-320N, India) following AOAC (2000) Method 985.35 [ 9 ]. Calcium (Ca), iron (Fe), and zinc (Zn) were analyzed using an air–acetylene flame. Absorbance for Fe and Zn was measured at 248.3 nm and 213.9 nm, respectively, and concentrations were calculated using standard calibration curves prepared from analytical-grade iron wire and ZnO. For calcium determination, absorbance was measured at 422.7 nm after the addition of 2.5 mL of LaCl₃ solution, and concentrations were estimated using a standard solution prepared from CaCO₃. Sodium (Na) and potassium (K) contents were determined using a flame photometer with standard solutions prepared from NaCl and KCl, respectively. Phosphorus content was estimated using the ammonium molybdovanadate colourimetric method (AOAC, 2000; Method 965.17) [ 9 ]. Briefly, 1 mL of the digested sample was diluted to 100 mL with de-ionized water. From this solution, 5 mL aliquots were taken in triplicate, and 0.5 mL of ammonium molybdovanadate reagent and 0.2 mL of aminonaphtholsulphonic acid were added. After standing for 10 min for colour development, absorbance was measured at 410 nm using a UV–visible spectrophotometer (VWR UV-6300PC, India). Phosphorus concentration was calculated from a standard calibration curve prepared using K₂HPO₄. Mineral element contents were expressed as mg/100 g dry weight using the standard calculation formula Element (mg/100 g) = (C × DF) / (W × 10) Where: µg/mL represents the concentration of the element in micrograms per millilitre, DF is the dilution factor (50 mL for Ca, Fe, Zn, Na, and K; 100 mL for P), Sample mass db represents the sample mass on a dry matter basis. 2.3. Determination of anti-nutritional factors 2.3.1. Alkaloids Alkaloid content was determined following the method of Harborne (1973) [ 10 ]. 2.5 g of finely powdered sample was accurately weighed and extracted with 50 mL of 10% acetic acid in absolute ethanol. The mixture was allowed to stand for 4 h and then filtered through Whatman No. 1 filter paper. The filtrate was concentrated to one-quarter of its original volume using a water bath at 90°C. Alkaloids were precipitated by the addition of concentrated ammonium hydroxide (NH₄OH). The precipitate formed was washed with dilute ammonium hydroxide and filtered. The residue was dried in a hot air oven at 70°C to constant weight and expressed as percentage of alkaloids in the sample. Alkaloid (%) = W2-W1/W x100 where, W1 = Weight before drying, W2 = Weight after drying, W = Sample weight 2.3.2. Tannins Condensed tannins were determined using the modified vanillin–HCl method [ 11 ]. Briefly, 0.5 g of finely ground sample was extracted with 50 mL of 1% HCl in methanol and allowed to stand for 20 min with occasional shaking. The mixture was filtered through Whatman No. 1 filter paper to obtain a clear filtrate. An aliquot (1 mL) of the filtrate was transferred into a test tube, and 5 mL of freshly prepared vanillin–HCl reagent was added. The reagent was prepared by mixing equal volumes of 8% (v/v) concentrated HCl in methanol and 4% (w/v) vanillin in methanol. The reaction mixture was incubated at room temperature for 20 min to allow colour development. Absorbance was measured at 500 nm using a UV–visible spectrophotometer. Tannin content was quantified from a standard calibration curve prepared using catechin and expressed as mg catechin equivalents per g dry weight. 2.3.3. Oxalates Oxalate content was determined using the AOAC (1990) official method [ 9 ]. Oxalate ions in the sample extract were precipitated by the addition of a calcium-containing reagent to form insoluble calcium oxalate. The precipitate was filtered and thoroughly washed to remove impurities, then dissolved in sulfuric acid.The liberated oxalate was titrated against standardized potassium permanganate (KMnO₄) solution under acidic conditions until a persistent pale pink endpoint was obtained. Oxalate content was calculated based on the volume and concentration of the titrant used and expressed as mg/g dry weight. 2.3.4. Phytates Phytate content was determined following the method of Vaintraub and Lapteva [ 12 ]. Briefly, 1 g of sample was extracted with 20 mL of 0.2 M HCl and stirred continuously for 1 h at room temperature. The mixture was filtered through Whatman No. 1 filter paper to obtain a clear filtrate.An aliquot (2 mL) of the filtrate was reacted with 2 mL of 0.2 M ferric chloride (FeCl₃) solution and heated in a boiling water bath for 30 min to precipitate ferric phytate. After cooling to room temperature, the precipitate was filtered and dissolved in 3 mL of 0.5 M NaOH, followed by the addition of 1.5 mL distilled water. The solution was neutralized with 1.5 mL of 1.5 M H₂SO₄, and 2 mL of Wade reagent (0.03% FeCl₃ and 0.3% sulfosalicylic acid) was added.The mixture was allowed to develop colour for 10 min, and absorbance was measured at 500 nm using a UV–visible spectrophotometer. Phytate content was calculated from a standard calibration curve prepared using phytic acid and expressed as mg/g dry weight. 2.4. Molar Ratios and Mineral Bioavailability Molar ratios were calculated to assess potential mineral interactions affecting bioavailability. Molar ratios of phytate to minerals (Ca, Zn, and Fe) were calculated by dividing the moles of phytate (phytate content/660 g mol⁻¹) by the moles of the respective minerals (Ca = 40 g mol⁻¹; Zn = 65 g mol⁻¹; Fe = 56 g mol⁻¹).The oxalate:Ca molar ratio was calculated by dividing the moles of oxalate (oxalate content/88 g mol⁻¹) by the moles of calcium. The calculated molar ratios were compared with the critical values reported by WHO/FAO (2004)[ 13 ] to assess mineral bioavailability. 2.5. Statistical Analysis All analyses were performed in triplicate and results were expressed as mean ± standard deviation. Statistical differences between species were evaluated using a two-way t-test followed by Fisher’s least significant difference (LSD) test at p < 0.05 using SAS version 9.3. Prior to multivariate analysis, data were standardized using Z-score normalization to eliminate scale differences among variables. Pearson correlation analysis and principal component analysis (PCA) were performed to explore relationships among mineral elements and antinutritional factors. Hierarchical cluster analysis (HCA) based on Euclidean distance and average linkage was used to visualize sample grouping patterns. Multivariate analyses were performed using mean values and should be interpreted as exploratory. 3. Results and discussion 3.1. Mineral contents Mineral content analysis of both tubers revealed significant differences (p < 0.05) in the concentrations of sodium, potassium, calcium, iron, magnesium, and selenium (Table 1 ; Fig. 1 ). Both species exhibited appreciable levels of macro- and micronutrients, indicating notable biochemical variability between the taxa. Macronutrient analysis showed that Brachystelma vartakii contained higher amounts of sodium, potassium, phosphorus, and magnesium, whereas B. ariyittaparensis exhibited a comparatively higher calcium content. Sodium and potassium function as key electrolytes involved in maintaining intracellular and extracellular ionic balance and play important roles in regulating plasma volume, acid–base equilibrium, and neuromuscular activity [ 14 ]. Magnesium participates in numerous physiological processes, and adequate intake is associated with the prevention of cardiomyopathy, muscle degeneration, growth retardation, immunological dysfunction, and related metabolic disorders [ 15 ]. Calcium and phosphorus are essential for the development and maintenance of bones, teeth, and normal muscle function [ 16 ]. Micronutrient evaluation indicated that B. ariyittaparensis is relatively richer in iron and selenium, whereas B. vartakii contains higher zinc levels. Micronutrient deficiencies, particularly of iron and zinc, remain major global public health concerns affecting nearly one-third of the world’s population [ 17 – 19 ], while selenium deficiency also affects substantial populations worldwide [ 20 ]. The observed mineral profiles suggest that both Brachystelma species possess noteworthy nutritional attributes. Overall, these underexplored geophytic taxa may serve as supplementary plant-based sources of essential macro- and micronutrients. Table 1 Mineral composition of tubers of Brachystelma ariyittaparensis (BA) and B. vartakii (BV) (mg/100 g dry weight). Values are presented as mean ± standard deviation (n = 3). Species Sodium Potassium Calcium Iron Zinc Magnesium Selenium Phosphorus B. ariyittaparensis (BA) 5.93 ± 0.20 332.33 ± 2.52 212.00 ± 2.65 44.67 ± 1.53 3.23 ± 0.25 102.67 ± 1.55 7.70 ± 0.27 264.00 ± 1.73 B. vartakii (BV) 7.67 ± 0.53 720.00 ± 2.00 182.67 ± 2.52 26.33 ± 1.15 5.20 ± 0.20 144.67 ± 1.53 3.67 ± 0.15 278.33 ± 2.08 3.2. Mineral ratios The mineral composition and relative proportions in the tubers of B. ariyittaparensis and B. vartakii provide important insight into their biochemical and nutritional relevance. The calculated mineral ratios are presented in Table 2 and Fig. 2 . Evaluation of these ratios is useful for assessing the biological significance of the tubers and their possible physiological implications. The Na:K ratio is an important dietary indicator in the prevention and management of hypertension [ 21 ]. A lower sodium-to-potassium ratio is considered beneficial for cardiovascular health, and foods with Na:K values less than 1 are generally recommended for blood pressure regulation [ 22 ]. In the present study, both tubers exhibited Na:K ratios below unity, indicating favourable nutritional attributes. Notably, B. vartakii showed a lower ratio (0.011) compared with B. ariyittaparensis (0.018), suggesting comparatively greater potential for supporting cardiovascular health. Calcium and magnesium act synergistically in maintaining bone integrity and metabolic balance. An appropriate Ca:Mg ratio is essential because excessive calcium relative to magnesium may contribute to vascular calcification and related complications [ 23 ]. The higher Ca:Mg ratio observed in B. ariyittaparensis suggests that this species may be particularly relevant for enhancing dietary calcium intake. Overall, the mineral concentrations and their relative proportions indicate meaningful biochemical variation between the two taxa. Understanding these ratios helps predict the biological relevance of the tubers and their potential nutritional implications. Compared with B. vartakii , B. ariyittaparensis exhibited a higher Fe:Zn ratio (13.83), which may be advantageous in dietary contexts aimed at improving iron intake; however, balanced intake of both minerals remains essential for optimal immune and metabolic function. The Ca:P ratio is another critical index for bone mineralization. Although an ideal dietary Ca:P ratio is generally considered to be > 1, values above 0.5 are regarded as nutritionally acceptable [ 24 ]. Both tubers contained appreciable levels of calcium and phosphorus, with B. ariyittaparensis showing a relatively higher Ca:P ratio (0.80), indicating potential relevance for bone health. Furthermore, B. ariyittaparensis exhibited higher selenium levels, suggesting possible advantages in antioxidant support, whereas B. vartakii showed relatively higher zinc levels, which may better support immune function and tissue repair. Collectively, the mineral ratio analysis indicates species-specific nutritional attributes: B. ariyittaparensis appears more associated with parameters linked to iron status and bone health, while B. vartakii shows features consistent with cardiovascular and metabolic support due to its lower Na:K ratio and more balanced Ca:Mg relationship. Table 2 Mineral molar ratios of tubers of Brachystelma ariyittaparensis (BA) and B. vartakii (BV). Values represent calculated molar ratios based on mineral concentrations (dry weight basis). Species Na:K Ca:Mg Se:Zn Fe:Zn Ca:P Mg:Ca B. ariyittaparensis (BA) 0.018 2.07 2.38 13.84 0.80 0.48 B. vartakii (BV) 0.011 1.26 0.71 5.06 0.66 0.79 3.3. Anti-nutritional content Antinutritional compounds are known to interfere with nutrient absorption and may contribute to mineral deficiencies when present at elevated levels. The antinutritional composition of the two Brachystelma tubers is presented in Table 3 and Fig. 3 . Such compounds are commonly detected in many plant-derived foods, and their potential adverse effects can often be minimized through appropriate processing methods. Phytates are known to reduce the bioavailability of essential minerals such as calcium, iron, and zinc through chelation. In the present study, phytate levels in both tubers were relatively low and comparable to those reported in commonly consumed tubers. For instance, potato ( Solanum tuberosum ) contains phytate levels ranging from 0.12 to 0.24 mg/g dry weight [ 25 ], while sweet potato typically contains less than 0.20 mg/g dry weight [ 26 ]. The low phytate content observed here suggests minimal interference with mineral absorption. Nevertheless, conventional processing methods such as soaking and fermentation can further reduce phytate levels if required [ 27 ]. Oxalates can form insoluble complexes with calcium, thereby reducing calcium bioavailability and potentially contributing to kidney stone formation. The oxalate contents of B. ariyittaparensis (0.64 ± 0.016 mg/g dry weight) and B. vartakii (0.716 ± 0.005 mg/g dry weight) showed a trend toward significance (p = 0.072). These values fall within the range reported for several tropical tubers. For example, yams ( Dioscorea spp.) contain oxalate levels ranging from 0.4 to 3.0 mg/g dry weight, whereas cassava ( Manihot esculenta ) may contain 1.0 to 5.0 mg/g dry weight [ 28 ]. Alkaloids are secondary metabolites that may exert antinutritional or toxic effects at elevated concentrations. In the present study, both tubers contained measurable levels of alkaloids, with a significant difference observed between the species (p < 0.05). However, alkaloid toxicity can be effectively reduced through common household processing methods. Peeling has been reported to reduce glycoalkaloid content by approximately 80%, as these compounds are largely concentrated beneath the skin [ 29 ]. Similarly, boiling can reduce glycoalkaloid levels in potatoes by 40–50% [ 30 ]. Therefore, combined processing approaches such as peeling followed by boiling are likely to further minimize alkaloid levels in these tubers. Tannins are known to inhibit protein digestibility and interfere with iron absorption. Both tubers exhibited moderately higher tannin levels than potato (< 1 mg/g dry weight) but were comparable to yam, which typically contains 2–5 mg/g dry weight [ 31 , 32 ]. The inhibitory effect of tannins on iron absorption can be mitigated by consuming vitamin C–rich foods alongside tannin-containing diets [ 33 ]. Overall, the antinutritional factors detected in the two Brachystelma species were within ranges comparable to commonly consumed tuber crops. While alkaloid levels were relatively higher, the values appear manageable through standard processing methods. Phytate and tannin contents did not differ significantly between the species (p > 0.05), whereas alkaloid levels showed significant variation (p < 0.05). The difference in oxalate content approached significance. These findings underscore the importance of characterizing antinutritional profiles in underexplored geophytic taxa while also indicating their potential suitability as supplementary plant resources. Table 3 Antinutritional composition of tubers of Brachystelma ariyittaparensis (BA) and B. vartakii (BV) (mg/g dry weight). Values are presented as mean ± standard deviation (n = 3). Species Phytate Oxalate Alkaloids Tannins B. ariyittaparensis (BA) 0.150 ± 0.011 0.640 ± 0.016 15.20 ± 0.57 4.23 ± 0.57 B. vartakii (BV) 0.143 ± 0.001 0.716 ± 0.005 18.60 ± 0.02 4.73 ± 0.12 3.4. Molar ratios and bioavailability of minerals The antinutrient-to-mineral molar ratios in B. ariyittaparensis (BA) and B. vartakii (BV) tubers provide insight into the predicted bioavailability of essential minerals such as iron, zinc, and calcium. Antinutritional factors, including phytates, oxalates, and tannins, are known to chelate mineral ions and thereby reduce their intestinal absorption, ultimately influencing the nutritional quality of plant-derived foods. The calculated molar ratios and inferred mineral bioavailability of the two Brachystelma species are presented in Table 4 . The low phytate:Fe ratios observed in both samples indicate minimal inhibition of iron absorption and suggest favourable predicted iron bioavailability from these tubers [ 34 ]. Similarly, the phytate:Zn ratios were below critical limits, indicating that zinc bioavailability is unlikely to be substantially impaired, which is important for maintaining immune function and cellular metabolism [ 35 ]. The oxalate:Ca ratios further suggest that oxalates are unlikely to significantly interfere with calcium absorption in these species, indicating favourable predicted calcium bioavailability. Adequate calcium uptake is essential for maintaining healthy bones and normal muscle function [ 36 ]. Although tannins may exert a mild inhibitory effect on mineral absorption, their calculated ratios indicate only a limited influence on iron availability and a modest potential effect on zinc absorption [ 37 ]. Overall, the favourable antinutrient-to-mineral ratios observed in B. ariyittaparensis and B. vartakii underscore the biochemical potential of these underexplored geophytic taxa. The results suggest that essential minerals present in these species are reasonably bioaccessible and may contribute positively to dietary mineral intake. Nevertheless, further in vivo bioavailability and processing studies are recommended to validate these findings. Table 4 Antinutrient-to-mineral molar ratios of tubers of Brachystelma ariyittaparensis (BA) and B. vartakii (BV). Values represent calculated molar ratios based on dry weight mineral and antinutrient concentrations Species Phytate:Ca Phytate:Fe Phytate:Zn Oxalate:Ca Tannins:Zn Tannins:Fe B. ariyittaparensis (BA) 4.29 × 10⁻⁵ 2.84 × 10⁻⁴ 4.60 × 10⁻³ 1.34 × 10⁻³ 5.04 × 10⁻² 3.12 × 10⁻³ B. vartakii (BV) 4.76 × 10⁻⁵ 4.61 × 10⁻⁵ 2.73 × 10⁻³ 1.74 × 10⁻³ 3.50 × 10⁻² 5.90 × 10⁻³ The correlation analysis revealed distinct associations between mineral elements and antinutritional factors, indicating potential interactions that may influence mineral bioavailability. Positive correlations among certain macroelements suggest coordinated accumulation patterns in the tubers. However, multivariate results should be interpreted cautiously, and future studies using larger sample sizes are recommended. 4. Conclusion The present study demonstrates that the tubers of Brachystelma ariyittaparensis and B. vartakii possess noteworthy biochemical and nutritional attributes as underexplored plant resources. Both species contained appreciable levels of essential macro- and micronutrients, with distinct mineral advantages observed between the two taxa. The favourable Na:K ratios indicate potential relevance for cardiovascular health, while the Ca:Mg and Ca:P relationships suggest possible contributions to bone-related nutritional functions. Although antinutritional factors such as phytates, oxalates, tannins, and alkaloids were detected, their levels were generally comparable to those reported in commonly consumed tubers. Importantly, the calculated antinutrient-to-mineral molar ratios were below critical thresholds, indicating favourable predicted bioavailability of iron, zinc, and calcium. Overall, these findings highlight the biochemical potential of Brachystelma tubers as supplementary plant-based resources that may contribute to improving dietary mineral intake. However, further studies on processing optimization, safety evaluation, and in vivo bioavailability are required before recommending wider dietary utilization. The present investigation is based on in vitro estimations and a limited sample set; therefore, comprehensive in vivo validation and broader population-level assessments are reasonable. Declarations Data availability The data produced or analyzed in this study can be obtained from the corresponding author upon reasonable request. Acknowledgements The authors thank Dr. P. Biju, Department of Botany, Government College, Kasaragod, Kerala, India, for assistance in plant selection, collection, and taxonomic authentication. Funding The authors received no specific funding for this work. Author information Authors and Affiliations Department of Botany, Sree Narayana College(Affiliated to Kannur University), Kannur, India Resmi P Thomas & Jeeshna MV Contributions RPT carried out experiments, evaluated the data and wrote the manuscript. The research was planned by JMV, who also oversaw, edited, and reviewed the paper. The manuscript has been viewed and approved by authors and is now ready for publishing. Corresponding author Correspondence to Resmi P Thomas. Ethics declarations Ethics approval and consent to participate Fresh tubers of Brachystelma ariyittaparensis Kambale & S.R.Yadav and Brachystelma vartakii Kambale & S.R.Yadav were collected from natural populations in Northern Kerala, India during the study period.Collection of plant specimens complied with relevant institutional, national and international guidelines for plant research. The collection was conducted for academic research purposes and did not involve protected or endangered species. No specific permits were required for the collection of these species. The collected plant specimens were taxonomically identified by Dr. P. Biju, Department of Botany, Government College,Kasaragod, Kerala, India, based on standard taxonomic descriptions. Voucher specimens were prepared and deposited in the Calicut University Herbarium (CALI) Kerala, India. The herbarium accession numbers are 7444 for Brachystelma ariyittaparensis and 7443 for Brachystelma vartakii . Consent for publication All authors have read and approved the final manuscript and consented to publication. Competing interests The authors declare no competing interests. References Prasad K, Sasi S, Venu P. Diversity and distribution of Brachystelma R.Br. in the Indian subcontinent. Rheedea. 2016;26(1):1–18. Prasad K, Venu P. A taxonomic revision of Brachystelma (Apocynaceae: Asclepiadoideae) in India. Phytotaxa. 2021;510(1):1–28. Moteetee A, Moffett RO. A review of ethnobotanical studies in South Africa. 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Nutr Rev. 2012;70(3):153–64. https://doi.org/10.1111/j.1753-4887.2012.00466.x . Adeyeye EI, Aye A. Nutritional implications of calcium and phosphorus ratios in diets. J Food Sci Technol. 2005;42(2):123–8. Ertan E. Phytate and its implications in human health. Food Chem. 1997;58(1):3–6. Woolfie AB. Phytate content in various food products. J Nutr. 1992;34(2):123–30. Reddy P, Phytate. Impact on mineral absorption and strategies to reduce its content. Food Sci Nutr. 2002;56(1):45–58. Bradbury JH, Holloway WD. Chemistry of Tropical Root Crops: Significance for Nutrition and Agriculture in the Pacific. Canberra: ACIAR; 1988. pp. 76–104. Friedman M, McDonald GM. Nutritional and health benefits of potatoes. Am J Potato Res. 1997;74(1):25–35. Bushway AA, Buzby JC, He H. Reduction of glycoalkaloid levels in potatoes. J Food Sci. 1984;49(2):525–8. Friedman M. Nutritional value of potatoes. Food Rev Int. 1997;13(2):221–40. Coursey DG. Tannins in yams ( Dioscorea spp.) and their effect on human nutrition. J Sci Food Agric. 1967;18(7):411–7. https://doi.org/10.1002/jsfa.2740180705 . Hallberg L, Hultén L, Gleerup A. Iron absorption from the whole diet: The role of vitamin C. Am J Clin Nutr. 1989;49(4):752–7. Hurrell RF, Egli I. Iron bioavailability and dietary reference values. Am J Clin Nutr. 2010;91(5):S1461–7. https://doi.org/10.3945/ajcn.2010.28674F . Gibson RS, Ferguson EL, Lehrfeld J. The role of food-based strategies in improving micronutrient status: A review. J Nutr. 2010;140(3):605–14. https://doi.org/10.3945/jn.109.113980 . Heaney RP, Weaver CM. Calcium bioavailability from calcium carbonate and calcium citrate. J Am Coll Nutr. 1990;9(5):484–91. https://doi.org/10.1080/07315724.1990.10720345 . Sandberg AS. Bioavailability of minerals in vegetarian diets. Am J Clin Nutr. 2002;78(3):S633–9. https://doi.org/10.1093/ajcn/78.3.633S . Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 27 Apr, 2026 Reviews received at journal 11 Apr, 2026 Reviews received at journal 02 Apr, 2026 Reviewers agreed at journal 23 Mar, 2026 Reviewers agreed at journal 19 Mar, 2026 Reviewers invited by journal 19 Mar, 2026 Editor invited by journal 17 Mar, 2026 Editor assigned by journal 16 Mar, 2026 Submission checks completed at journal 14 Mar, 2026 First submitted to journal 13 Mar, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8992980","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":609767206,"identity":"5267634e-f44f-457c-bfcf-22c353c6fb7b","order_by":0,"name":"Resmi P. Thomas¹","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA6ElEQVRIiWNgGAWjYFACxsYDMMYDIMnDR4SWhgMMCWBGswFICxsx9kC1MLBJgElCynXbDzcc+Pnjnpz8tMNtlV9z7GTYGJgfPrqBR4vZmcSGgz0JxcYGtxPbbstuSwY6jM3YOAeflgOJDQd4EhISN0gDtUhuYwZq4WGTxqvl/MOGg38SEurnz05sK5bcVk+ElhuJDYeBtiQwAB3G+HHbYWK0PGw4LJOWYLjhdmKzNOO24zxszIT8cj794cM3Ngny8rPTH378ua3anp+9+eFjfFpQADMPmCRWOQgw/iBF9SgYBaNgFIwYAAC3eU25sjrdswAAAABJRU5ErkJggg==","orcid":"","institution":"Sree Narayana College","correspondingAuthor":true,"prefix":"","firstName":"Resmi","middleName":"P.","lastName":"Thomas¹","suffix":""},{"id":609767207,"identity":"f474b8e6-5d8b-4a8c-a994-4a3001e83275","order_by":1,"name":"Jeeshna M V","email":"","orcid":"","institution":"Sree Narayana College","correspondingAuthor":false,"prefix":"","firstName":"Jeeshna","middleName":"M","lastName":"V","suffix":""}],"badges":[],"createdAt":"2026-02-28 07:56:20","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8992980/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8992980/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":105229222,"identity":"5eda74b7-b671-4f8a-8f43-18bae67fd95e","added_by":"auto","created_at":"2026-03-23 17:26:03","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":71518,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eComparative mineral composition of tubers of \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eBrachystelma ariyittaparensis\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e and \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eB. vartakii\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e. Values represent mean ± SD (n = 3).\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-8992980/v1/065a55959b2f34d4b68d5c31.png"},{"id":105229197,"identity":"19824868-8574-48f8-af58-c4e58883a7be","added_by":"auto","created_at":"2026-03-23 17:25:48","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":54677,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eComparative mineral molar ratios in tubers of \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eBrachystelma ariyittaparensis\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e and \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eB. vartakii\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e. Values are derived from calculated molar ratios\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-8992980/v1/e0cfa76b747666909fd23737.png"},{"id":105229212,"identity":"8c5e676a-b8be-4473-a804-9e86c126b928","added_by":"auto","created_at":"2026-03-23 17:25:50","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":41298,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eComparative antinutritional composition of tubers of \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eBrachystelma ariyittaparensis\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e and \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eB. vartakii\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e. Values represent mean ± SD (n = 3)\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-8992980/v1/9eab6eea1df54cc9da22535f.png"},{"id":105229194,"identity":"b7bee548-2875-45bc-8067-67ebe37a3ee3","added_by":"auto","created_at":"2026-03-23 17:25:45","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":64947,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eClustered heatmap with hierarchical dendrogram showing the relative distribution of mineral elements and antinutritional factors in \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eBrachystelma ariyittaparensis\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (BA) and \u003c/strong\u003e\u003cem\u003e\u003cstrong\u003eB. vartakii\u003c/strong\u003e\u003c/em\u003e\u003cstrong\u003e (BV) tubers (values standardized as Z-scores).\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-8992980/v1/0b002bb97a3577a4083242ce.png"},{"id":105564019,"identity":"b19da939-fabf-4618-b8c5-91367dcde467","added_by":"auto","created_at":"2026-03-27 12:48:28","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1411422,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8992980/v1/f344142a-a50c-4308-9021-8c6194029fc7.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Biochemical and Mineral Profiling of Two Recently Described Brachystelma Species from Northern Kerala India","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eMost members of the genus \u003cem\u003eBrachystelma\u003c/em\u003e R.Br. remain poorly studied in India due to their short life span, ephemeral growth habit, and the presence of subterranean storage organs such as bulbs, corms, tubers, or rhizomes. These species are predominantly distributed in the arid and semi-arid regions of the country. Their narrow seasonality and restricted distribution have resulted in their under-representation in early floristic accounts and herbarium records.\u003c/p\u003e \u003cp\u003e \u003cem\u003eBrachystelma\u003c/em\u003e R.Br. is the second largest genus in the tribe Ceropegieae of the subfamily Asclepiadoideae (Apocynaceae) and comprises approximately 160 species distributed mainly in the Old World tropics. The genus occurs in sub-Saharan Africa, India, Sri Lanka, Southeast Asia, and northern Australia [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Following recent taxonomic revision, the genus in India includes 38 taxa, of which 34 are native and 21 are endemic [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Despite this diversity, most species remain inadequately investigated because of their short life cycle, slow growth, and limited distribution. Moreover, their natural habitats are increasingly affected by anthropogenic pressures.\u003c/p\u003e \u003cp\u003eSeveral members of \u003cem\u003eBrachystelma\u003c/em\u003e have been reported to possess notable medicinal and nutritional attributes. The tubers of many species are traditionally consumed either raw or after processing by indigenous communities in Africa, Asia, and Australia [\u003cspan additionalcitationids=\"CR4\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Beyond their dietary use, these plants hold considerable ethnobotanical importance, particularly as emergency food resources in many regions.\u003c/p\u003e \u003cp\u003eThe tubers of \u003cem\u003eBrachystelma\u003c/em\u003e species are characterized by high moisture and nutrient content, enhancing their potential as plant-based food resources. Owing to their high water content, nomadic communities and hunters in East Africa have traditionally used them to alleviate thirst in water-scarce environments. The tubers are also consumed by wild animals such as hedgehogs, moles, and blesmols and are generally regarded as non-toxic to humans and animals [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Numerous species within the genus have documented medicinal applications. For example, \u003cem\u003eB. edulis\u003c/em\u003e, \u003cem\u003eB. naorojii\u003c/em\u003e, and \u003cem\u003eB. togoense\u003c/em\u003e have been reported to possess therapeutic properties for the treatment of stomach ache, headache, and wound healing [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAmong the many species of \u003cem\u003eBrachystelma\u003c/em\u003e, detailed nutritional information is currently available only for \u003cem\u003eB. edulis\u003c/em\u003e and \u003cem\u003eB. naorojii\u003c/em\u003e. Deshmukh and Rathod [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] reported that the tubers of \u003cem\u003eB. edulis\u003c/em\u003e are rich in protein, fibre, and carbohydrates compared with common vegetables. Its carbohydrate content is comparable to that of African leafy vegetables such as gallwort, pigweed, and purslane. The fibre content of \u003cem\u003eB. edulis\u003c/em\u003e (8%) is similar to that of \u003cem\u003eCeropegia hirsuta\u003c/em\u003e (9.1%), and both species exhibit comparable protein levels. While leaves and tubers show similar ash and moisture contents, the tubers possess higher dry matter content. These findings support the nutritional potential of \u003cem\u003eBrachystelma\u003c/em\u003e species as supplementary plant resources.\u003c/p\u003e \u003cp\u003eFurther investigation of lesser-known \u003cem\u003eBrachystelma\u003c/em\u003e species may expand their recognized utilization potential and support their inclusion in food and nutrition security programmes. However, despite the ethnobotanical importance of the genus, detailed information on mineral bioavailability and antinutritional interactions in recently described taxa from Northern Kerala remains scarce. Therefore, the present study aimed to evaluate the mineral composition, antinutritional factors, and predicted mineral bioavailability of tubers of \u003cem\u003eBrachystelma ariyittaparensis\u003c/em\u003e and \u003cem\u003eB. vartakii\u003c/em\u003e from Northern Kerala, India.\u003c/p\u003e"},{"header":"2. Materials and methods","content":"\u003ch2\u003e2.1. Sample collection\u003c/h2\u003e \u003cp\u003eFresh tubers of \u003cem\u003eBrachystelma ariyittaparensi\u003c/em\u003es (P.Biju,Josekutty \u0026amp; Augustine) K.Prasad \u0026amp; Venu and \u003cem\u003eBrachystelma vartakii\u003c/em\u003e Kambale \u0026amp; S.R. Yadav were collected from natural populations in Northern Kerala, India, during the study period. The plant specimens were authenticated through morphological characteristics in accordance with standard floras. The geographical coordinates of the collection site are approximately 12.27\u0026deg;N, 75.13\u0026deg;E. Fresh tubers of the chosen species were collected, cleaned, and subjected to biochemical and mineral analysis.Voucher specimens were prepared and deposited in the Calicut University Herbarium (CALI) of the Department of Botany at University of Calicut, Kerala, India for future reference. The herbarium accession numbers are 7444 for \u003cem\u003eBrachystelma ariyittaparensis\u003c/em\u003e and 7443 for \u003cem\u003eBrachystelma vartakii\u003c/em\u003e respectively.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2.Determination of minerals content\u003c/h2\u003e \u003cp\u003eApproximately 3.0 g of each dried sample was carbonized on a heating plate and dry-ashed in a muffle furnace (Biotechnics India BTI-36) at 550\u0026deg;C until complete ashing was achieved. The resulting white ash was dissolved in 5 mL of 6 N HCl, evaporated to dryness on a hot plate, and further treated with 7 mL of 3 N HCl. The digest was finally diluted to 50 mL with de-ionized water for mineral analysis.\u003c/p\u003e \u003cp\u003eMineral contents were determined using an atomic absorption spectrophotometer (AAS) (Drawell DW-320N, India) following AOAC (2000) Method 985.35 [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Calcium (Ca), iron (Fe), and zinc (Zn) were analyzed using an air\u0026ndash;acetylene flame. Absorbance for Fe and Zn was measured at 248.3 nm and 213.9 nm, respectively, and concentrations were calculated using standard calibration curves prepared from analytical-grade iron wire and ZnO.\u003c/p\u003e \u003cp\u003eFor calcium determination, absorbance was measured at 422.7 nm after the addition of 2.5 mL of LaCl₃ solution, and concentrations were estimated using a standard solution prepared from CaCO₃. Sodium (Na) and potassium (K) contents were determined using a flame photometer with standard solutions prepared from NaCl and KCl, respectively.\u003c/p\u003e \u003cp\u003ePhosphorus content was estimated using the ammonium molybdovanadate colourimetric method (AOAC, 2000; Method 965.17) [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Briefly, 1 mL of the digested sample was diluted to 100 mL with de-ionized water. From this solution, 5 mL aliquots were taken in triplicate, and 0.5 mL of ammonium molybdovanadate reagent and 0.2 mL of aminonaphtholsulphonic acid were added. After standing for 10 min for colour development, absorbance was measured at 410 nm using a UV\u0026ndash;visible spectrophotometer (VWR UV-6300PC, India). Phosphorus concentration was calculated from a standard calibration curve prepared using K₂HPO₄.\u003c/p\u003e \u003cp\u003eMineral element contents were expressed as mg/100 g dry weight using the standard calculation formula\u003c/p\u003e \u003cp\u003eElement (mg/100 g) = (C \u0026times; DF) / (W \u0026times; 10)\u003c/p\u003e \u003cp\u003eWhere:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003e\u0026micro;g/mL represents the concentration of the element in micrograms per millilitre,\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eDF is the dilution factor (50 mL for Ca, Fe, Zn, Na, and K; 100 mL for P),\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eSample mass db represents the sample mass on a dry matter basis.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3. Determination of anti-nutritional factors\u003c/h2\u003e \u003cdiv id=\"Sec6\" class=\"Section3\"\u003e \u003ch2\u003e2.3.1. Alkaloids\u003c/h2\u003e \u003cp\u003eAlkaloid content was determined following the method of Harborne (1973) [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. 2.5 g of finely powdered sample was accurately weighed and extracted with 50 mL of 10% acetic acid in absolute ethanol. The mixture was allowed to stand for 4 h and then filtered through Whatman No. 1 filter paper.\u003c/p\u003e \u003cp\u003eThe filtrate was concentrated to one-quarter of its original volume using a water bath at 90\u0026deg;C. Alkaloids were precipitated by the addition of concentrated ammonium hydroxide (NH₄OH). The precipitate formed was washed with dilute ammonium hydroxide and filtered. The residue was dried in a hot air oven at 70\u0026deg;C to constant weight and expressed as percentage of alkaloids in the sample.\u003c/p\u003e \u003cp\u003e \u003cem\u003eAlkaloid\u003c/em\u003e (%) = W2-W1/W x100\u003c/p\u003e \u003cp\u003e \u003cem\u003ewhere, W1\u0026thinsp;=\u0026thinsp;Weight before drying, W2\u0026thinsp;=\u0026thinsp;Weight after drying, W\u0026thinsp;=\u0026thinsp;Sample weight\u003c/em\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section3\"\u003e \u003ch2\u003e2.3.2. Tannins\u003c/h2\u003e \u003cp\u003eCondensed tannins were determined using the modified vanillin\u0026ndash;HCl method [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Briefly, 0.5 g of finely ground sample was extracted with 50 mL of 1% HCl in methanol and allowed to stand for 20 min with occasional shaking. The mixture was filtered through Whatman No. 1 filter paper to obtain a clear filtrate.\u003c/p\u003e \u003cp\u003eAn aliquot (1 mL) of the filtrate was transferred into a test tube, and 5 mL of freshly prepared vanillin\u0026ndash;HCl reagent was added. The reagent was prepared by mixing equal volumes of 8% (v/v) concentrated HCl in methanol and 4% (w/v) vanillin in methanol. The reaction mixture was incubated at room temperature for 20 min to allow colour development.\u003c/p\u003e \u003cp\u003eAbsorbance was measured at 500 nm using a UV\u0026ndash;visible spectrophotometer. Tannin content was quantified from a standard calibration curve prepared using catechin and expressed as mg catechin equivalents per g dry weight.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section3\"\u003e \u003ch2\u003e2.3.3. Oxalates\u003c/h2\u003e \u003cp\u003eOxalate content was determined using the AOAC (1990) official method [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Oxalate ions in the sample extract were precipitated by the addition of a calcium-containing reagent to form insoluble calcium oxalate. The precipitate was filtered and thoroughly washed to remove impurities, then dissolved in sulfuric acid.The liberated oxalate was titrated against standardized potassium permanganate (KMnO₄) solution under acidic conditions until a persistent pale pink endpoint was obtained. Oxalate content was calculated based on the volume and concentration of the titrant used and expressed as mg/g dry weight.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section3\"\u003e \u003ch2\u003e2.3.4. Phytates\u003c/h2\u003e \u003cp\u003ePhytate content was determined following the method of Vaintraub and Lapteva [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Briefly, 1 g of sample was extracted with 20 mL of 0.2 M HCl and stirred continuously for 1 h at room temperature. The mixture was filtered through Whatman No. 1 filter paper to obtain a clear filtrate.An aliquot (2 mL) of the filtrate was reacted with 2 mL of 0.2 M ferric chloride (FeCl₃) solution and heated in a boiling water bath for 30 min to precipitate ferric phytate. After cooling to room temperature, the precipitate was filtered and dissolved in 3 mL of 0.5 M NaOH, followed by the addition of 1.5 mL distilled water. The solution was neutralized with 1.5 mL of 1.5 M H₂SO₄, and 2 mL of Wade reagent (0.03% FeCl₃ and 0.3% sulfosalicylic acid) was added.The mixture was allowed to develop colour for 10 min, and absorbance was measured at 500 nm using a UV\u0026ndash;visible spectrophotometer. Phytate content was calculated from a standard calibration curve prepared using phytic acid and expressed as mg/g dry weight.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e2.4. Molar Ratios and Mineral Bioavailability\u003c/h2\u003e \u003cp\u003eMolar ratios were calculated to assess potential mineral interactions affecting bioavailability. Molar ratios of phytate to minerals (Ca, Zn, and Fe) were calculated by dividing the moles of phytate (phytate content/660 g mol⁻\u0026sup1;) by the moles of the respective minerals (Ca\u0026thinsp;=\u0026thinsp;40 g mol⁻\u0026sup1;; Zn\u0026thinsp;=\u0026thinsp;65 g mol⁻\u0026sup1;; Fe\u0026thinsp;=\u0026thinsp;56 g mol⁻\u0026sup1;).The oxalate:Ca molar ratio was calculated by dividing the moles of oxalate (oxalate content/88 g mol⁻\u0026sup1;) by the moles of calcium. The calculated molar ratios were compared with the critical values reported by WHO/FAO (2004)[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] to assess mineral bioavailability.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e2.5. Statistical Analysis\u003c/h2\u003e \u003cp\u003eAll analyses were performed in triplicate and results were expressed as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation. Statistical differences between species were evaluated using a two-way t-test followed by Fisher\u0026rsquo;s least significant difference (LSD) test at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05 using SAS version 9.3.\u003c/p\u003e \u003cp\u003ePrior to multivariate analysis, data were standardized using Z-score normalization to eliminate scale differences among variables. Pearson correlation analysis and principal component analysis (PCA) were performed to explore relationships among mineral elements and antinutritional factors. Hierarchical cluster analysis (HCA) based on Euclidean distance and average linkage was used to visualize sample grouping patterns. Multivariate analyses were performed using mean values and should be interpreted as exploratory.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results and discussion","content":"\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e3.1. Mineral contents\u003c/h2\u003e \u003cp\u003eMineral content analysis of both tubers revealed significant differences (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05) in the concentrations of sodium, potassium, calcium, iron, magnesium, and selenium (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e; Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Both species exhibited appreciable levels of macro- and micronutrients, indicating notable biochemical variability between the taxa.\u003c/p\u003e \u003cp\u003eMacronutrient analysis showed that \u003cem\u003eBrachystelma vartakii\u003c/em\u003e contained higher amounts of sodium, potassium, phosphorus, and magnesium, whereas \u003cem\u003eB. ariyittaparensis\u003c/em\u003e exhibited a comparatively higher calcium content. Sodium and potassium function as key electrolytes involved in maintaining intracellular and extracellular ionic balance and play important roles in regulating plasma volume, acid\u0026ndash;base equilibrium, and neuromuscular activity [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Magnesium participates in numerous physiological processes, and adequate intake is associated with the prevention of cardiomyopathy, muscle degeneration, growth retardation, immunological dysfunction, and related metabolic disorders [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Calcium and phosphorus are essential for the development and maintenance of bones, teeth, and normal muscle function [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eMicronutrient evaluation indicated that \u003cem\u003eB. ariyittaparensis\u003c/em\u003e is relatively richer in iron and selenium, whereas \u003cem\u003eB. vartakii\u003c/em\u003e contains higher zinc levels. Micronutrient deficiencies, particularly of iron and zinc, remain major global public health concerns affecting nearly one-third of the world\u0026rsquo;s population [\u003cspan additionalcitationids=\"CR18\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e], while selenium deficiency also affects substantial populations worldwide [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. The observed mineral profiles suggest that both \u003cem\u003eBrachystelma\u003c/em\u003e species possess noteworthy nutritional attributes. Overall, these underexplored geophytic taxa may serve as supplementary plant-based sources of essential macro- and micronutrients.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMineral composition of tubers of \u003cem\u003eBrachystelma ariyittaparensis\u003c/em\u003e (BA) and \u003cem\u003eB. vartakii\u003c/em\u003e (BV) (mg/100 g dry weight). Values are presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (n\u0026thinsp;=\u0026thinsp;3).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"9\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSpecies\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSodium\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePotassium\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eCalcium\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eIron\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eZinc\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eMagnesium\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eSelenium\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003ePhosphorus\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eB. ariyittaparensis\u003c/em\u003e (BA)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e5.93\u0026thinsp;\u0026plusmn;\u0026thinsp;0.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e332.33\u0026thinsp;\u0026plusmn;\u0026thinsp;2.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e212.00\u0026thinsp;\u0026plusmn;\u0026thinsp;2.65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e44.67\u0026thinsp;\u0026plusmn;\u0026thinsp;1.53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e3.23\u0026thinsp;\u0026plusmn;\u0026thinsp;0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e102.67\u0026thinsp;\u0026plusmn;\u0026thinsp;1.55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e7.70\u0026thinsp;\u0026plusmn;\u0026thinsp;0.27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c9\"\u003e \u003cp\u003e264.00\u0026thinsp;\u0026plusmn;\u0026thinsp;1.73\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eB. vartakii\u003c/em\u003e (BV)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e7.67\u0026thinsp;\u0026plusmn;\u0026thinsp;0.53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e720.00\u0026thinsp;\u0026plusmn;\u0026thinsp;2.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e182.67\u0026thinsp;\u0026plusmn;\u0026thinsp;2.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e26.33\u0026thinsp;\u0026plusmn;\u0026thinsp;1.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e5.20\u0026thinsp;\u0026plusmn;\u0026thinsp;0.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e144.67\u0026thinsp;\u0026plusmn;\u0026thinsp;1.53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e3.67\u0026thinsp;\u0026plusmn;\u0026thinsp;0.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c9\"\u003e \u003cp\u003e278.33\u0026thinsp;\u0026plusmn;\u0026thinsp;2.08\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e3.2. Mineral ratios\u003c/h2\u003e \u003cp\u003eThe mineral composition and relative proportions in the tubers of \u003cem\u003eB. ariyittaparensis\u003c/em\u003e and \u003cem\u003eB. vartakii\u003c/em\u003e provide important insight into their biochemical and nutritional relevance. The calculated mineral ratios are presented in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. Evaluation of these ratios is useful for assessing the biological significance of the tubers and their possible physiological implications.\u003c/p\u003e \u003cp\u003eThe Na:K ratio is an important dietary indicator in the prevention and management of hypertension [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. A lower sodium-to-potassium ratio is considered beneficial for cardiovascular health, and foods with Na:K values less than 1 are generally recommended for blood pressure regulation [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. In the present study, both tubers exhibited Na:K ratios below unity, indicating favourable nutritional attributes. Notably, \u003cem\u003eB. vartakii\u003c/em\u003e showed a lower ratio (0.011) compared with \u003cem\u003eB. ariyittaparensis\u003c/em\u003e (0.018), suggesting comparatively greater potential for supporting cardiovascular health.\u003c/p\u003e \u003cp\u003eCalcium and magnesium act synergistically in maintaining bone integrity and metabolic balance. An appropriate Ca:Mg ratio is essential because excessive calcium relative to magnesium may contribute to vascular calcification and related complications [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. The higher Ca:Mg ratio observed in \u003cem\u003eB. ariyittaparensis\u003c/em\u003e suggests that this species may be particularly relevant for enhancing dietary calcium intake.\u003c/p\u003e \u003cp\u003eOverall, the mineral concentrations and their relative proportions indicate meaningful biochemical variation between the two taxa. Understanding these ratios helps predict the biological relevance of the tubers and their potential nutritional implications.\u003c/p\u003e \u003cp\u003eCompared with \u003cem\u003eB. vartakii\u003c/em\u003e, \u003cem\u003eB. ariyittaparensis\u003c/em\u003e exhibited a higher Fe:Zn ratio (13.83), which may be advantageous in dietary contexts aimed at improving iron intake; however, balanced intake of both minerals remains essential for optimal immune and metabolic function. The Ca:P ratio is another critical index for bone mineralization. Although an ideal dietary Ca:P ratio is generally considered to be \u0026gt;\u0026thinsp;1, values above 0.5 are regarded as nutritionally acceptable [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Both tubers contained appreciable levels of calcium and phosphorus, with \u003cem\u003eB. ariyittaparensis\u003c/em\u003e showing a relatively higher Ca:P ratio (0.80), indicating potential relevance for bone health.\u003c/p\u003e \u003cp\u003eFurthermore, \u003cem\u003eB. ariyittaparensis\u003c/em\u003e exhibited higher selenium levels, suggesting possible advantages in antioxidant support, whereas \u003cem\u003eB. vartakii\u003c/em\u003e showed relatively higher zinc levels, which may better support immune function and tissue repair. Collectively, the mineral ratio analysis indicates species-specific nutritional attributes: \u003cem\u003eB. ariyittaparensis\u003c/em\u003e appears more associated with parameters linked to iron status and bone health, while \u003cem\u003eB. vartakii\u003c/em\u003e shows features consistent with cardiovascular and metabolic support due to its lower Na:K ratio and more balanced Ca:Mg relationship.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMineral molar ratios of tubers of \u003cem\u003eBrachystelma ariyittaparensis\u003c/em\u003e (BA) and \u003cem\u003eB. vartakii\u003c/em\u003e (BV). Values represent calculated molar ratios based on mineral concentrations (dry weight basis).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSpecies\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNa:K\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCa:Mg\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSe:Zn\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eFe:Zn\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eCa:P\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eMg:Ca\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eB. ariyittaparensis\u003c/em\u003e (BA)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.018\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e13.84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.80\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.48\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eB. vartakii\u003c/em\u003e (BV)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.011\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e5.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.66\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.79\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003e3.3. Anti-nutritional content\u003c/h2\u003e \u003cp\u003eAntinutritional compounds are known to interfere with nutrient absorption and may contribute to mineral deficiencies when present at elevated levels. The antinutritional composition of the two \u003cem\u003eBrachystelma\u003c/em\u003e tubers is presented in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. Such compounds are commonly detected in many plant-derived foods, and their potential adverse effects can often be minimized through appropriate processing methods.\u003c/p\u003e \u003cp\u003ePhytates are known to reduce the bioavailability of essential minerals such as calcium, iron, and zinc through chelation. In the present study, phytate levels in both tubers were relatively low and comparable to those reported in commonly consumed tubers. For instance, potato (\u003cem\u003eSolanum tuberosum\u003c/em\u003e) contains phytate levels ranging from 0.12 to 0.24 mg/g dry weight [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e], while sweet potato typically contains less than 0.20 mg/g dry weight [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. The low phytate content observed here suggests minimal interference with mineral absorption. Nevertheless, conventional processing methods such as soaking and fermentation can further reduce phytate levels if required [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eOxalates can form insoluble complexes with calcium, thereby reducing calcium bioavailability and potentially contributing to kidney stone formation. The oxalate contents of \u003cem\u003eB. ariyittaparensis\u003c/em\u003e (0.64\u0026thinsp;\u0026plusmn;\u0026thinsp;0.016 mg/g dry weight) and \u003cem\u003eB. vartakii\u003c/em\u003e (0.716\u0026thinsp;\u0026plusmn;\u0026thinsp;0.005 mg/g dry weight) showed a trend toward significance (p\u0026thinsp;=\u0026thinsp;0.072). These values fall within the range reported for several tropical tubers. For example, yams (\u003cem\u003eDioscorea\u003c/em\u003e spp.) contain oxalate levels ranging from 0.4 to 3.0 mg/g dry weight, whereas cassava (\u003cem\u003eManihot esculenta\u003c/em\u003e) may contain 1.0 to 5.0 mg/g dry weight [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAlkaloids are secondary metabolites that may exert antinutritional or toxic effects at elevated concentrations. In the present study, both tubers contained measurable levels of alkaloids, with a significant difference observed between the species (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05). However, alkaloid toxicity can be effectively reduced through common household processing methods. Peeling has been reported to reduce glycoalkaloid content by approximately 80%, as these compounds are largely concentrated beneath the skin [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. Similarly, boiling can reduce glycoalkaloid levels in potatoes by 40\u0026ndash;50% [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. Therefore, combined processing approaches such as peeling followed by boiling are likely to further minimize alkaloid levels in these tubers.\u003c/p\u003e \u003cp\u003eTannins are known to inhibit protein digestibility and interfere with iron absorption. Both tubers exhibited moderately higher tannin levels than potato (\u0026lt;\u0026thinsp;1 mg/g dry weight) but were comparable to yam, which typically contains 2\u0026ndash;5 mg/g dry weight [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. The inhibitory effect of tannins on iron absorption can be mitigated by consuming vitamin C\u0026ndash;rich foods alongside tannin-containing diets [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eOverall, the antinutritional factors detected in the two \u003cem\u003eBrachystelma\u003c/em\u003e species were within ranges comparable to commonly consumed tuber crops. While alkaloid levels were relatively higher, the values appear manageable through standard processing methods. Phytate and tannin contents did not differ significantly between the species (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05), whereas alkaloid levels showed significant variation (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05). The difference in oxalate content approached significance. These findings underscore the importance of characterizing antinutritional profiles in underexplored geophytic taxa while also indicating their potential suitability as supplementary plant resources.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u003cb\u003eAntinutritional composition of tubers of\u003c/b\u003e \u003cb\u003eBrachystelma ariyittaparensis\u003c/b\u003e \u003cb\u003e(BA) and\u003c/b\u003e \u003cb\u003eB. vartakii\u003c/b\u003e \u003cb\u003e(BV) (mg/g dry weight). Values are presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (n\u0026thinsp;=\u0026thinsp;3).\u003c/b\u003e\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSpecies\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePhytate\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eOxalate\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eAlkaloids\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eTannins\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eB. ariyittaparensis\u003c/em\u003e (BA)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.150\u0026thinsp;\u0026plusmn;\u0026thinsp;0.011\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.640\u0026thinsp;\u0026plusmn;\u0026thinsp;0.016\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e15.20\u0026thinsp;\u0026plusmn;\u0026thinsp;0.57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e4.23\u0026thinsp;\u0026plusmn;\u0026thinsp;0.57\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eB. vartakii\u003c/em\u003e (BV)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.143\u0026thinsp;\u0026plusmn;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.716\u0026thinsp;\u0026plusmn;\u0026thinsp;0.005\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e18.60\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e4.73\u0026thinsp;\u0026plusmn;\u0026thinsp;0.12\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003e3.4. Molar ratios and bioavailability of minerals\u003c/h2\u003e \u003cp\u003eThe antinutrient-to-mineral molar ratios in \u003cem\u003eB. ariyittaparensis\u003c/em\u003e (BA) and \u003cem\u003eB. vartakii\u003c/em\u003e (BV) tubers provide insight into the predicted bioavailability of essential minerals such as iron, zinc, and calcium. Antinutritional factors, including phytates, oxalates, and tannins, are known to chelate mineral ions and thereby reduce their intestinal absorption, ultimately influencing the nutritional quality of plant-derived foods. The calculated molar ratios and inferred mineral bioavailability of the two \u003cem\u003eBrachystelma\u003c/em\u003e species are presented in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eThe low phytate:Fe ratios observed in both samples indicate minimal inhibition of iron absorption and suggest favourable predicted iron bioavailability from these tubers [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. Similarly, the phytate:Zn ratios were below critical limits, indicating that zinc bioavailability is unlikely to be substantially impaired, which is important for maintaining immune function and cellular metabolism [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe oxalate:Ca ratios further suggest that oxalates are unlikely to significantly interfere with calcium absorption in these species, indicating favourable predicted calcium bioavailability. Adequate calcium uptake is essential for maintaining healthy bones and normal muscle function [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]. Although tannins may exert a mild inhibitory effect on mineral absorption, their calculated ratios indicate only a limited influence on iron availability and a modest potential effect on zinc absorption [\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eOverall, the favourable antinutrient-to-mineral ratios observed in \u003cem\u003eB. ariyittaparensis\u003c/em\u003e and \u003cem\u003eB. vartakii\u003c/em\u003e underscore the biochemical potential of these underexplored geophytic taxa. The results suggest that essential minerals present in these species are reasonably bioaccessible and may contribute positively to dietary mineral intake. Nevertheless, further in vivo bioavailability and processing studies are recommended to validate these findings.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u003cb\u003eAntinutrient-to-mineral molar ratios of tubers of\u003c/b\u003e \u003cb\u003eBrachystelma ariyittaparensis\u003c/b\u003e \u003cb\u003e(BA) and\u003c/b\u003e \u003cb\u003eB. vartakii\u003c/b\u003e \u003cb\u003e(BV). Values represent calculated molar ratios based on dry weight mineral and antinutrient concentrations\u003c/b\u003e\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026times;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026times;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026times;\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026times;\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026times;\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026times;\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSpecies\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePhytate:Ca\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePhytate:Fe\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePhytate:Zn\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eOxalate:Ca\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eTannins:Zn\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eTannins:Fe\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eB. ariyittaparensis\u003c/em\u003e (BA)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026times;\" colname=\"c2\"\u003e \u003cp\u003e4.29 \u0026times; 10⁻⁵\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026times;\" colname=\"c3\"\u003e \u003cp\u003e2.84 \u0026times; 10⁻⁴\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026times;\" colname=\"c4\"\u003e \u003cp\u003e4.60 \u0026times; 10⁻\u0026sup3;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026times;\" colname=\"c5\"\u003e \u003cp\u003e1.34 \u0026times; 10⁻\u0026sup3;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026times;\" colname=\"c6\"\u003e \u003cp\u003e5.04 \u0026times; 10⁻\u0026sup2;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026times;\" colname=\"c7\"\u003e \u003cp\u003e3.12 \u0026times; 10⁻\u0026sup3;\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eB. vartakii\u003c/em\u003e (BV)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026times;\" colname=\"c2\"\u003e \u003cp\u003e4.76 \u0026times; 10⁻⁵\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026times;\" colname=\"c3\"\u003e \u003cp\u003e4.61 \u0026times; 10⁻⁵\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026times;\" colname=\"c4\"\u003e \u003cp\u003e2.73 \u0026times; 10⁻\u0026sup3;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026times;\" colname=\"c5\"\u003e \u003cp\u003e1.74 \u0026times; 10⁻\u0026sup3;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026times;\" colname=\"c6\"\u003e \u003cp\u003e3.50 \u0026times; 10⁻\u0026sup2;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026times;\" colname=\"c7\"\u003e \u003cp\u003e5.90 \u0026times; 10⁻\u0026sup3;\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe correlation analysis revealed distinct associations between mineral elements and antinutritional factors, indicating potential interactions that may influence mineral bioavailability. Positive correlations among certain macroelements suggest coordinated accumulation patterns in the tubers. However, multivariate results should be interpreted cautiously, and future studies using larger sample sizes are recommended.\u003c/p\u003e \u003c/div\u003e"},{"header":"4. Conclusion","content":"\u003cp\u003eThe present study demonstrates that the tubers of \u003cem\u003eBrachystelma ariyittaparensis\u003c/em\u003e and \u003cem\u003eB. vartakii\u003c/em\u003e possess noteworthy biochemical and nutritional attributes as underexplored plant resources. Both species contained appreciable levels of essential macro- and micronutrients, with distinct mineral advantages observed between the two taxa. The favourable Na:K ratios indicate potential relevance for cardiovascular health, while the Ca:Mg and Ca:P relationships suggest possible contributions to bone-related nutritional functions. Although antinutritional factors such as phytates, oxalates, tannins, and alkaloids were detected, their levels were generally comparable to those reported in commonly consumed tubers. Importantly, the calculated antinutrient-to-mineral molar ratios were below critical thresholds, indicating favourable predicted bioavailability of iron, zinc, and calcium.\u003c/p\u003e \u003cp\u003eOverall, these findings highlight the biochemical potential of \u003cem\u003eBrachystelma\u003c/em\u003e tubers as supplementary plant-based resources that may contribute to improving dietary mineral intake. However, further studies on processing optimization, safety evaluation, and in vivo bioavailability are required before recommending wider dietary utilization. The present investigation is based on in vitro estimations and a limited sample set; therefore, comprehensive in vivo validation and broader population-level assessments are reasonable.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data produced or analyzed in this study can be obtained from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors thank Dr. P. Biju, Department of Botany, Government College, Kasaragod, Kerala, India, for assistance in plant selection, collection, and taxonomic authentication.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors received no specific funding for this work.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor information\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors and Affiliations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDepartment of Botany, Sree Narayana College(Affiliated to Kannur University), Kannur, India\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eResmi P Thomas \u0026amp; Jeeshna MV\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eContributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eRPT carried out experiments, evaluated the data and wrote the manuscript. The research was planned by JMV, who also oversaw, edited, and reviewed the paper. The manuscript has been viewed and approved by authors and is now ready for publishing.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCorresponding author\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eCorrespondence to Resmi P Thomas.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics declarations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFresh tubers of \u003cem\u003eBrachystelma ariyittaparensis\u003c/em\u003e Kambale \u0026amp; S.R.Yadav and \u003cem\u003eBrachystelma vartakii\u003c/em\u003e Kambale \u0026amp; S.R.Yadav were collected from natural populations in Northern Kerala, India during the study period.Collection of plant specimens complied with relevant institutional, national and international guidelines for plant research. \u0026nbsp;The collection was conducted for academic research purposes and did not involve protected or endangered species. No specific permits were required for the collection of these species. The collected plant specimens were taxonomically identified by Dr. P. Biju, Department of Botany, Government College,Kasaragod, Kerala, India, based on standard taxonomic descriptions. Voucher specimens were prepared and deposited in the Calicut University Herbarium (CALI) Kerala, India. The herbarium accession numbers are 7444 for \u003cem\u003eBrachystelma ariyittaparensis\u003c/em\u003e and 7443 for \u003cem\u003eBrachystelma vartakii\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors have read and approved the final manuscript and consented to publication.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003ePrasad K, Sasi S, Venu P. Diversity and distribution of \u003cem\u003eBrachystelma\u003c/em\u003e R.Br. in the Indian subcontinent. Rheedea. 2016;26(1):1\u0026ndash;18.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePrasad K, Venu P. A taxonomic revision of \u003cem\u003eBrachystelma\u003c/em\u003e (Apocynaceae: Asclepiadoideae) in India. 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Am J Clin Nutr. 2002;78(3):S633\u0026ndash;9. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1093/ajcn/78.3.633S\u003c/span\u003e\u003cspan address=\"10.1093/ajcn/78.3.633S\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"discover-plants","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Discover Plants](https://link.springer.com/journal/44372)","snPcode":"44372","submissionUrl":"https://submission.springernature.com/new-submission/44372/3","title":"Discover Plants","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Discover Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Brachystelma, endemic geophytes, mineral profiling, antinutritional factors, wild edible plants, plant nutritional traits","lastPublishedDoi":"10.21203/rs.3.rs-8992980/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8992980/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eWild edible tubers represent underutilized plant resources with potential nutritional significance. The present study evaluated the mineral composition, antinutritional factors, and predicted mineral bioavailability of tubers from two recently described species, \u003cem\u003eBrachystelma ariyittaparensis\u003c/em\u003e and \u003cem\u003eB. vartakii\u003c/em\u003e, collected from Northern Kerala, India. Mineral contents were determined using atomic absorption spectrophotometry and flame photometry following AOAC protocols, while antinutritional factors (phytate, oxalate, tannin, and alkaloids) were quantified using established biochemical methods. Significant interspecific variation in mineral profiles was observed (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05). \u003cem\u003eB. vartakii\u003c/em\u003e exhibited higher concentrations of sodium, potassium, magnesium, phosphorus, and zinc, whereas \u003cem\u003eB. ariyittaparensis\u003c/em\u003e contained comparatively higher levels of calcium, iron, and selenium. Antinutrient levels in both species were within ranges reported for commonly consumed tubers. Molar ratio analysis suggested favourable predicted bioavailability of key minerals. The findings highlight the biochemical potential of these underexplored geophytic species and provide baseline data relevant to their nutritional evaluation and future utilization. However, further studies on processing effects, safety assessment, and in vivo validation are recommended.\u003c/p\u003e","manuscriptTitle":"Biochemical and Mineral Profiling of Two Recently Described Brachystelma Species from Northern Kerala India","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-23 17:25:27","doi":"10.21203/rs.3.rs-8992980/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-04-27T10:55:35+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-11T09:50:40+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-02T15:29:54+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"28260453664427859458716249166037876704","date":"2026-03-23T13:19:23+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"60002448250958307881729522105410676199","date":"2026-03-19T17:00:07+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-03-19T06:15:16+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-03-17T04:44:44+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-03-16T15:08:45+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-03-14T06:11:30+00:00","index":"","fulltext":""},{"type":"submitted","content":"Discover Plants","date":"2026-03-13T17:26:40+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"discover-plants","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Discover Plants](https://link.springer.com/journal/44372)","snPcode":"44372","submissionUrl":"https://submission.springernature.com/new-submission/44372/3","title":"Discover Plants","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Discover Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"307b0da3-78f2-484f-8c09-b3a1652d9d94","owner":[],"postedDate":"March 23rd, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-08T06:08:23+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-23 17:25:27","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8992980","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8992980","identity":"rs-8992980","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}