Anti-Plasmodial Activity and Elemental Analysis of the Stem Bark Extract of Caesalpinia pulcherrima

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Stem bark extracts and fractions were evaluated for in vivo antimalarial activity and elemental composition. Fractionation of the extracts was carried out using vacuum liquid chromatography (VLC), while elemental analysis was conducted using atomic absorption spectrophotometry (AAS). Antimalarial activity was assessed against Plasmodium berghei berghei in albino mice (20–30 g) using the 4-day suppressive test. Methanol–ethyl acetate stem bark extracts administered at doses of 200, 400, and 800 mg/kg produced dose-dependent chemo-suppression. The 200 mg/kg extract showed suppressive activities of 45.32%, 52.67%, 47.90%, and 24.17%; the 400 mg/kg extract showed 57.74%, 56.36%, 51.51%, and 30.35%; while the 800 mg/kg extract exhibited 63.29%, 62.09%, 54.24%, and 39.91%. These effects were lower than those of the standard drug chloroquine (5 mg/kg), which produced suppressive activities of 95.22%, 91.73%, 88.97%, and 86.22%. The results demonstrate that C. pulcherrima stem bark possesses significant antiplasmodial (suppressive) activity, supporting its traditional use in malaria treatment. Medicinal Chemistry Caesalpinia pulcherrima antiplasmodial antimalaria elemental composition AAS plant extraction Introduction Medicinal plants represent one of the richest sources of bioactive organic compounds and have contributed immensely to the discovery of new chemical entities used in medicine, cosmetics, food, and agrochemicals [ 1 ]. It has been reported that a significant proportion of modern pharmaceuticals are derived directly or indirectly from plant sources, highlighting the continued relevance of natural products in drug discovery [ 2 , 3 ]. Scientific investigation of medicinal plants is essential for documenting the therapeutic potential of indigenous flora, providing a rational basis for their traditional use, developing affordable and effective herbal medicines, discovering novel drug leads, and validating ethnomedicinal knowledge. Such investigations also contribute to the conservation of medicinal plant resources and the sustainable utilization of biodiversity [ 4 ]. The use of medicinal plants has gained increasing acceptance, even among educated populations in urban settings. This trend may be attributed to the declining efficacy of several conventional drugs used in the management of infectious diseases such as fever, gonorrhoea, asthma, and tuberculosis, as well as the increasing prevalence of antimicrobial resistance and the rising cost of prescription medicines [ 5 ]. Several studies have confirmed that antimicrobial resistance represents a major global health challenge, particularly in developing countries where access to effective healthcare is limited [ 6 , 7 ]. Furthermore, the rapid growth of the human population has placed significant pressure on modern healthcare systems, particularly in developing countries, thereby increasing reliance on natural herbal remedies. Herbal medicines are often perceived as affordable, accessible, and culturally acceptable alternatives to orthodox drugs [ 8 ]. The emergence of multidrug-resistant (MDR) pathogenic bacteria, including methicillin-resistant Staphylococcus aureus , Helicobacter pylori , and MDR Klebsiella pneumoniae , has further revived interest in plant-derived therapeutic agents with antimicrobial properties. Plant secondary metabolites such as alkaloids, flavonoids, tannins, and terpenoids have been shown to possess potent antimicrobial activities [ 9 ]. Malaria remains one of the most serious tropical parasitic diseases, accounting for substantial morbidity and mortality, especially among children and pregnant women [ 10 ]. The disease continues to pose a major public health and socioeconomic burden in endemic regions [ 11 ]. It is estimated that malaria affects approximately 300–400 million people worldwide, with about 1–2 million deaths recorded annually [ 12 ]. Africa continues to bear the highest burden of the disease due to widespread resistance to antimalarial drugs, insecticide resistance in mosquito vectors, environmental and climatic changes, population displacement, and increased human mobility. These factors have significantly complicated malaria control and elimination efforts in sub-Saharan Africa [ 13 ]. Although chloroquine, introduced in the 1950s, was once widely relied upon because of its safety, affordability, and efficacy, the development of resistance has severely limited its usefulness. The spread of chloroquine-resistant Plasmodium falciparum strains has necessitated the search for alternative antimalarial agents [ 14 ]. Artemisinin-based combination therapies (ACTs) have improved malaria treatment outcomes; however, challenges related to cost, accessibility, and emerging resistance persist [ 15 , 16 ]. Reports of delayed parasite clearance have raised concerns regarding the long-term effectiveness of ACTs [ 15 ]. Caesalpinia pulcherrima (Pride of Barbados) is a medicinal plant widely distributed in tropical and subtropical regions and extensively used in traditional medicine across Africa, Asia, and South America. Different parts of the plant have been reported to possess significant medicinal value. Among Nigerian communities, the aerial parts are used as abortifacients, emmenagogues, purgatives, stimulants, and emollients [ 17 ]. In Angola, root extracts are traditionally used for the treatment of intermittent fevers, while the leaves are employed as purgatives, tonics, antipyretics, and emmenagogues. The roots are also used folklorically in the management of convulsions, intermittent fevers, and lung and skin diseases [ 18 ]. In Chinese traditional medicine, the fruits, flowers, leaves, and stem bark are commonly used to treat ailments such as pyrexia, menoxenia, wheezing, bronchitis, and malaria infections [ 19 ]. The wide ethnomedicinal application of this plant suggests the presence of biologically active constituents with diverse pharmacological properties [ 20 ]. Scientific investigations have provided evidence supporting many of these traditional claims. Aqueous extracts of the fresh leaves and stem bark of C. pulcherrima have been reported to exhibit strong in vitro antimalarial, antifungal, antibacterial, and antioxidant activities. The observed biological activities have been attributed to the presence of bioactive phytochemicals such as flavonoids, phenolics, and terpenoids [ 21 ]. Chiang et al. [ 22 ] demonstrated that whole-plant extracts possess broad-spectrum in vitro antiviral activity, while seed extracts have been reported to show significant broad-spectrum antimicrobial effects [ 23 ]. Additionally, the flowers and leaf sap have been used in the treatment of swellings (anti-inflammatory activity), muscular and rheumatic pains (analgesic activity), and various cardiovascular conditions, further highlighting the plant’s broad pharmacological potential. Despite these reports, there is still limited in vivo evidence validating the antiplasmodial efficacy of the stem bark of Caesalpinia pulcherrima , particularly in relation to its traditional use for malaria treatment. In vivo studies are essential for establishing pharmacological relevance and validating therapeutic efficacy under physiological conditions [ 24 ]. The aim of this study was to evaluate the antiplasmodial activity of stem bark extracts and fractions of Caesalpinia pulcherrima . The specific objectives were to assess the in vivo suppressive antimalarial activity of the extracts against Plasmodium berghei in albino mice and to determine the elemental composition of the stem bark using Atomic Absorption Spectrophotometry. Elemental analysis provides important information on trace elements that may contribute to the therapeutic effects of medicinal plants [ 25 ] Materials and Methods Collection of Plant Materials and Preparation Fresh stem bark of Caesalpinia pulcherrima was harvested from Ugbowo Campus of the University of Benin, Nigeria. The was plant was sent to the Department of Pharmacognosy, Faculty of Pharmacy, University of Benin for identification and authentication. The collected stem bark was thoroughly washed with tap water to remove extraneous materials and air-dried at ambient temperature (30 ± 2 °C) for 14 days until a constant weight was obtained. The dried material was first reduced to coarse particles using a mortar and pestle and subsequently milled into a fine powder using a mechanical grinder. The powdered stem bark was stored in an airtight container and preserved at room temperature until required for further analysis. Extraction of Crude Powdered Sample Exactly 600 g of the powdered stem bark of Caesalpinia pulcherrima was exhaustively macerated in 2.5 L of methanol at room temperature for 72 hours with occasional stirring. The resulting mixture was first filtered through a clean cheesecloth and subsequently through Whatman No. 1 filter paper to obtain a clear filtrate. The filtrate was concentrated to dryness under reduced pressure using a rotary evaporator. The dried crude extract was weighed, and the percentage yield was calculated relative to the initial weight of the powdered stem bark. The extract was stored in an airtight container and kept refrigerated until required for further analysis. Vacuum Liquid Chromatography Forty grams (40 g) of the crude extract of Caesalpinia pulcherrima stem bark was thoroughly adsorbed onto silica gel and mixed until a free-flowing powder was obtained. The dry-packed sample was subjected to vacuum liquid chromatography using silica gel as the stationary phase. Elution was carried out sequentially with solvent systems of increasing polarity to obtain different fractions. The solvent systems used in the analysis include 100% n-hexane, 50% n-hexane and 50% ethyl acetate solution, 100% ethyl acetate, 50% methanol and 50% ethyl acetate solution, and 100% methanol. Each fraction obtained was concentrated to dryness under reduced pressure using a rotary evaporator. The resulting dried fractions were stored in airtight containers and kept refrigerated until required for further analysis Experimental Animals Swiss albino mice of either sex, weighing between 20 and 30 g, were obtained from the animal house of the Faculty of Pharmacy, University of Benin, Nigeria, and used for the study. The animals were housed in clean plastic cages at room temperature under a naturally illuminated environment. They were allowed to acclimatize to laboratory conditions for four weeks prior to the commencement of the experiment. The mice were fed with a standard pellet diet and had free access to clean drinking water ad libitum . All experimental procedures were carried out in accordance with the National Institutes of Health (NIH) Guide for the Care and Use of Laboratory Animals. Preparation of Giemsa Solution (Stock Giemsa) Three point five grams (3.5 g) of solid Giemsa stain was added to a mixture of 250 mL of methanol and 250 mL of glycerol in a dark reagent bottle. The mixture was shaken vigorously to ensure proper dissolution and then stored in a cupboard at room temperature for seven days to allow complete maturation before use in the analysis. Preparation of Phosphate Buffer Saline (PBS) 1.09g of disodium hydrogen phosphate and 0.32 g of sodium dihydrogen phosphate were dissolved in 100 mL of distilled water with continuous shaking. The pH of the solution was adjusted to 7.2 by the dropwise addition of 0.1 M sodium hydroxide solution. The buffer was then made up to volume, mixed thoroughly, and stored at room temperature until required. Parasite Inoculation Chloroquine sensitive plasmodium berghei (NK65) was obtained from the National Institute of Medical Research (NIMR), Lagos, Nigeria. Each mouse used in the experiment was infected intraperitoneally with 0.1ml of infected blood containing about 1× 10 7 parasitized red blood cells (PRBC). In a normal, unaffected mouse, the number of red blood cells in 1ml of blood is approximately 5×10 8 , while in an infected mouse, the number of red blood cells in 1ml of blood is reduced to 3×10 8 . This 1ml of parasitised red blood cell (containing 3×10 8 RBC) was diluted with 3ml of phosphate buffer saline to give; Therefore, scaling down the volume by a factor of 10, this will give; 1×10 7 PRBC in 0.1ml of blood. It is this quantity of 1×10 7 PRBC that was introduced into the mouse as 0.1ml. Sample Digestion One gram (1.0 g) of the powdered stem of Caesalpinia pulcherrima was accurately weighed into a digestion flask. Ten millilitres (10 mL) of perchloric acid (HClO₄) and 10 mL of nitric acid (HNO₃) were carefully added in a fume cupboard. The contents were gently swirled and heated under the fume cupboard for approximately 10 minutes until the evolution of brown nitrogen dioxide (NO₂) fumes was observed, indicating oxidation of the organic matter. The digest was then allowed to cool to room temperature, filtered, and quantitatively transferred into a 50 mL volumetric flask. The filtrate was diluted to the 50 mL mark with distilled water and mixed thoroughly. The digestion procedure was carried out in triplicate, including a reagent blank, and the resulting solutions were analysed for heavy metal content using an Atomic Absorption Spectrophotometer (AAS) Evaluation of the Suppressive Activity of Extract (Peter’s 4-Days Test) The suppressive antimalarial activity of the stem bark extract of Caesalpinia pulcherrima was evaluated using the standard 4-day suppressive test described by Knight and Peters (1980). On day one (D1), twenty-five Swiss albino mice were inoculated intraperitoneally with chloroquine-sensitive Plasmodium berghei berghei -infected red blood cells. The animals were randomly assigned to five groups (A–E) of five mice each, based on body weight. Treatments were administered once daily for four consecutive days (D1–D4) between 8:00 pm and 9:00 pm. Group A served as the negative control and received no treatment. Groups B, C, and D were administered the stem bark extract orally at doses of 200, 400, and 800 mg/kg body weight, respectively. Group E served as the positive control and received chloroquine at a dose of 5 mg/kg body weight orally. From day five (D5) to day eight (D8), blood samples were collected from the tail vein of each mouse for parasitological analysis. Thick and thin blood smears were prepared on clean glass slides, fixed with methanol, and stained with 4% Giemsa solution. After 45 minutes, the slides were rinsed with distilled water and allowed to air-dry. Parasitological examination was carried out using a light microscope, and parasitaemia was determined by counting parasitised red blood cells (PRBCs) and total red blood cells (RBCs) in ten different microscopic fields. Results and Discussion Results and Discussion The results obtained from the in vivo anti-plasmodia studies, and elemental analysis of the extract from the stem bark of C. pulcherrima are shown in Tables 1, 2 and 3 below Percentage yield of the extract The percentage yield of the stem bark extract of C. pulcherrima obtained was 18.98%. Comparison of %parasitaemia of the Stem Bark extract of C. pulcherrima and standard drug (chloroquine) Antimalarial activity of the stem bark extract of C. pulcherrima The stem bark extract of Caesalpinia pulcherrima demonstrated significant, dose-dependent antimalarial activity against chloroquine-sensitive Plasmodium berghei in Swiss albino mice, as reflected by percentage chemosuppression and mean survival time (Table 3). The extract at 200, 400, and 800 mg/kg produced progressive parasitaemia suppression from 45.32% to 63.29% on day 5, with corresponding increases in mean survival time from 17 to 26 days, compared to 14 days in the untreated control. The highest dose (800 mg/kg) exhibited the greatest chemosuppressive effect, confirming a clear dose-response relationship. Although chloroquine (5 mg/kg) showed superior suppression (86.22–95.22%) and survival (28 ± 0.45 days), the extract’s activity indicates substantial antiplasmodial potential. The observed effect may result from bioactive phytochemicals, such as flavonoids, alkaloids, and tannins, which are known to interfere with the intraerythrocytic development of Plasmodium species. Additionally, the elemental composition of the stem bark, including iron, copper, calcium, and sodium, may support haematological and physiological functions during infection, potentially enhancing host resilience and contributing to prolonged survival. These findings corroborate traditional use of C. pulcherrima for malaria treatment and suggest that the stem bark extract could serve as a complementary or alternative antimalarial agent, particularly in areas where access to conventional drugs is limited. The elemental analysis of Caesalpinia pulcherrima leaves revealed the presence of essential metals—sodium (11.73 ± 0.17 ppm), calcium (9.33 ± 3.46 ppm), iron (5.33 ± 1.25 ppm), and copper (0.22 ± 0.09 ppm)—with toxic lead being undetectable, indicating the safety of the extract for medicinal use. These elements may contribute synergistically to the plant’s antimalarial activity. Iron supports erythropoiesis and helps counter malaria-induced anaemia, while copper enhances antioxidant defences, reducing oxidative stress caused by parasitic infection. Calcium and sodium play a crucial role in maintaining erythrocyte stability and overall physiological homeostasis, which can enhance the delivery and efficacy of bioactive compounds. The absence of lead ensures no additional haematological or toxicological risk. Therefore, the combination of bioactive phytochemicals and supportive trace elements likely underpins the observed dose-dependent parasitemia suppression, highlighting both the pharmacological potential and nutritional value of C. pulcherrima in traditional malaria treatment. Conclusion The study found that the stem bark extract of Caesalpinia pulcherrima shows significant antiplasmodial activity, although it is less effective than chloroquine. This activity may be linked to bioactive compounds such as alkaloids, flavonoids, saponins, and tannins previously reported in the plant. While the specific active molecules were not identified, their presence suggests a potential for inhibiting Plasmodium growth. The findings support the traditional use of this plant for malaria treatment in Nigeria and recommend further research on isolating and characterizing the active compounds to develop affordable, plant-based antimalarial therapies. Declarations The study titled “Anti Plasmodial Activity and Elemental Analysis of the Stem Bark Extract of Caesalpinia pulcherrima" involved the use of Swiss albino mice (20–30 g) of either sex obtained from the University of Benin, Edo State, Nigeria. All animal handling and experimental procedures were conducted in accordance with the NIH Guide for the Care and Use of Laboratory Animals. The animals were maintained under standard laboratory conditions, as described in the methodology section of the manuscript. Oversight for the use of laboratory animals was provided by the University of Benin, where the animals were sourced and handled in line with institutional practices for animal care and use. Conflict of interest The authors declare no conflict of interest. References Pinto, A. C., Silva, D. H. S., Bolzani, V. S., Lopes, N. P., and Epifanio, R. A. (2002). Natural products: Activity, challenges and perspectives. Química Nova, 25 , 45–61. Newman, D. J., and Cragg, G. M. (2007). 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The treatise on Indian medicinal plants . NISCAIR. Chiu, N. Y., and Chang, K. H. (1992). The illustrated plants of Taiwan (Vol. 3). SMC Publishing. Sofowora, A. (2008). Medicinal plants and traditional medicine in Africa (3rd ed.). Spectrum Books. Adebayo, J. O., and Krettli, A. U. (2011). Potential antimalarials from Nigerian plants: A review. Journal of Ethnopharmacology, 133 (2), 289–302. Chiang, L. C., Chiang, W., & Chang, M. Y. (2002). Antiviral activity of Plantago major extracts and related compounds in vitro. Antiviral Research, 55 (1), 53–62. Ali, M. S., Azhar, I., and Amtul, Z. (1999). Antimicrobial screening of some Caesalpinia species. Fitoterapia, 70 , 299–304. Mswahili, M. E., Martin, G. L., Woo, J., Choi, G. J., and Jeong, Y. S. (2021). Antiplasmodial activity and cytotoxicity of medicinal plants traditionally used in malaria treatment. Biomolecules, 11 (12), Article 1750. Choukri, M., Abouabdillah, A., Bouabid, R., Abd-Elkader, O. H., Pacioglu, O., Boufahja, F., and Bourioug, M. (2022). Zn application through seed priming improves productivity and grain nutritional quality of silage corn. Saudi Journal of Biological Sciences, 29 (12), Article 103456. Ejigu, Y. W., and Endalifer, B. L. (2023). In vitro anti‑plasmodial activity of three selected medicinal plants that are used in local traditional medicine in Amhara region of Ethiopia . BMC Pharmacology and Toxicology, 24 , Article 30. Ogu, G. I., and Ekeanyanwu, R. C. (2010). Assessment of renal function of Nigerian children infected with Plasmodium falciparum . International Journal of Medicine and Medical Sciences, 2 (9), 251–255 Tables Tables 1 to 3 are available in the Supplementary Files section. Additional Declarations The authors declare no competing interests. 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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-8831025","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":588328487,"identity":"7da8fb69-3cca-4227-811e-60ddba4a2563","order_by":0,"name":"Matthew Edekin Oni","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5ElEQVRIiWNgGAWjYJACZgjF2PiAgUEiAczmwa+BsRmqpdmAVC0MbBJAgrAW3fbzxx8XVBxm4Jdubqvm3WGRxy/dwPjgbRtuLWZnkhmbZ5w5zCA552Dbbd4zEsWScw4wG87Fp+UAUAtv220GgxuJQC1tEokbbiSwSfPi03L+MVDLP4iWYpCW/TcS2H/j1XIDZEsDRAsz2BaJBDZm/FoeG87mOfafR3JGYrPk3DaJYokbQMacc/gclvjgM09Nmhy/RPrDD2/b6vL4ZyQf/PCmDLcWGECOCMYGwupHwSgYBaNgFOAFAKAYUOIhLOzbAAAAAElFTkSuQmCC","orcid":"https://orcid.org/0009-0008-7717-7863","institution":"University of Benin","correspondingAuthor":true,"prefix":"","firstName":"Matthew","middleName":"Edekin","lastName":"Oni","suffix":""}],"badges":[],"createdAt":"2026-02-09 13:36:50","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":true,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":true},"doi":"10.21203/rs.3.rs-8831025/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8831025/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":102982146,"identity":"39bb88c8-52ba-43f0-ad80-0ab447e5877d","added_by":"auto","created_at":"2026-02-19 09:12:27","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":583601,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8831025/v1/95259da1-d3a5-455c-94f3-97373512948a.pdf"},{"id":102982065,"identity":"13d1947d-265b-42ca-9049-1f3022e6bcf9","added_by":"auto","created_at":"2026-02-19 09:12:11","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":24509,"visible":true,"origin":"","legend":"","description":"","filename":"Table123.docx","url":"https://assets-eu.researchsquare.com/files/rs-8831025/v1/f054c51052140a8860705549.docx"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003eAnti-Plasmodial Activity and Elemental Analysis of the Stem Bark Extract of Caesalpinia pulcherrima\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eMedicinal plants represent one of the richest sources of bioactive organic compounds and have contributed immensely to the discovery of new chemical entities used in medicine, cosmetics, food, and agrochemicals [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. It has been reported that a significant proportion of modern pharmaceuticals are derived directly or indirectly from plant sources, highlighting the continued relevance of natural products in drug discovery [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Scientific investigation of medicinal plants is essential for documenting the therapeutic potential of indigenous flora, providing a rational basis for their traditional use, developing affordable and effective herbal medicines, discovering novel drug leads, and validating ethnomedicinal knowledge. Such investigations also contribute to the conservation of medicinal plant resources and the sustainable utilization of biodiversity [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe use of medicinal plants has gained increasing acceptance, even among educated populations in urban settings. This trend may be attributed to the declining efficacy of several conventional drugs used in the management of infectious diseases such as fever, gonorrhoea, asthma, and tuberculosis, as well as the increasing prevalence of antimicrobial resistance and the rising cost of prescription medicines [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Several studies have confirmed that antimicrobial resistance represents a major global health challenge, particularly in developing countries where access to effective healthcare is limited [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Furthermore, the rapid growth of the human population has placed significant pressure on modern healthcare systems, particularly in developing countries, thereby increasing reliance on natural herbal remedies. Herbal medicines are often perceived as affordable, accessible, and culturally acceptable alternatives to orthodox drugs [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. The emergence of multidrug-resistant (MDR) pathogenic bacteria, including methicillin-resistant \u003cem\u003eStaphylococcus aureus\u003c/em\u003e, \u003cem\u003eHelicobacter pylori\u003c/em\u003e, and MDR \u003cem\u003eKlebsiella pneumoniae\u003c/em\u003e, has further revived interest in plant-derived therapeutic agents with antimicrobial properties. Plant secondary metabolites such as alkaloids, flavonoids, tannins, and terpenoids have been shown to possess potent antimicrobial activities [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eMalaria remains one of the most serious tropical parasitic diseases, accounting for substantial morbidity and mortality, especially among children and pregnant women [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. The disease continues to pose a major public health and socioeconomic burden in endemic regions [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. It is estimated that malaria affects approximately 300\u0026ndash;400\u0026nbsp;million people worldwide, with about 1\u0026ndash;2\u0026nbsp;million deaths recorded annually [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Africa continues to bear the highest burden of the disease due to widespread resistance to antimalarial drugs, insecticide resistance in mosquito vectors, environmental and climatic changes, population displacement, and increased human mobility. These factors have significantly complicated malaria control and elimination efforts in sub-Saharan Africa [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Although chloroquine, introduced in the 1950s, was once widely relied upon because of its safety, affordability, and efficacy, the development of resistance has severely limited its usefulness. The spread of chloroquine-resistant \u003cem\u003ePlasmodium falciparum\u003c/em\u003e strains has necessitated the search for alternative antimalarial agents [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Artemisinin-based combination therapies (ACTs) have improved malaria treatment outcomes; however, challenges related to cost, accessibility, and emerging resistance persist [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Reports of delayed parasite clearance have raised concerns regarding the long-term effectiveness of ACTs [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003cem\u003eCaesalpinia pulcherrima\u003c/em\u003e (Pride of Barbados) is a medicinal plant widely distributed in tropical and subtropical regions and extensively used in traditional medicine across Africa, Asia, and South America. Different parts of the plant have been reported to possess significant medicinal value. Among Nigerian communities, the aerial parts are used as abortifacients, emmenagogues, purgatives, stimulants, and emollients [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. In Angola, root extracts are traditionally used for the treatment of intermittent fevers, while the leaves are employed as purgatives, tonics, antipyretics, and emmenagogues. The roots are also used folklorically in the management of convulsions, intermittent fevers, and lung and skin diseases [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. In Chinese traditional medicine, the fruits, flowers, leaves, and stem bark are commonly used to treat ailments such as pyrexia, menoxenia, wheezing, bronchitis, and malaria infections [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. The wide ethnomedicinal application of this plant suggests the presence of biologically active constituents with diverse pharmacological properties [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eScientific investigations have provided evidence supporting many of these traditional claims. Aqueous extracts of the fresh leaves and stem bark of \u003cem\u003eC. pulcherrima\u003c/em\u003e have been reported to exhibit strong in vitro antimalarial, antifungal, antibacterial, and antioxidant activities. The observed biological activities have been attributed to the presence of bioactive phytochemicals such as flavonoids, phenolics, and terpenoids [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Chiang et al. [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e] demonstrated that whole-plant extracts possess broad-spectrum in vitro antiviral activity, while seed extracts have been reported to show significant broad-spectrum antimicrobial effects [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Additionally, the flowers and leaf sap have been used in the treatment of swellings (anti-inflammatory activity), muscular and rheumatic pains (analgesic activity), and various cardiovascular conditions, further highlighting the plant\u0026rsquo;s broad pharmacological potential.\u003c/p\u003e \u003cp\u003eDespite these reports, there is still limited in vivo evidence validating the antiplasmodial efficacy of the stem bark of \u003cem\u003eCaesalpinia pulcherrima\u003c/em\u003e, particularly in relation to its traditional use for malaria treatment. In vivo studies are essential for establishing pharmacological relevance and validating therapeutic efficacy under physiological conditions [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. The aim of this study was to evaluate the antiplasmodial activity of stem bark extracts and fractions of \u003cem\u003eCaesalpinia pulcherrima\u003c/em\u003e. The specific objectives were to assess the in vivo suppressive antimalarial activity of the extracts against \u003cem\u003ePlasmodium berghei\u003c/em\u003e in albino mice and to determine the elemental composition of the stem bark using Atomic Absorption Spectrophotometry. Elemental analysis provides important information on trace elements that may contribute to the therapeutic effects of medicinal plants [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003e\u003cstrong\u003eCollection of Plant Materials and Preparation\u003cbr\u003e\u003c/strong\u003eFresh stem bark of \u003cem\u003eCaesalpinia pulcherrima\u003c/em\u003e was harvested from Ugbowo Campus of the University of Benin, Nigeria. The was plant was sent to the Department of Pharmacognosy, Faculty of Pharmacy, University of Benin for identification and authentication. The collected stem bark was thoroughly washed with tap water to remove extraneous materials and air-dried at ambient temperature (30 \u0026plusmn; 2 \u0026deg;C) for 14 days until a constant weight was obtained. The dried material was first reduced to coarse particles using a mortar and pestle and subsequently milled into a fine powder using a mechanical grinder. The powdered stem bark was stored in an airtight container and preserved at room temperature until required for further analysis.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eExtraction of Crude Powdered Sample\u003c/strong\u003e\u003cbr\u003eExactly 600 g of the powdered stem bark of \u003cem\u003eCaesalpinia pulcherrima\u003c/em\u003e was exhaustively macerated in 2.5 L of methanol at room temperature for 72 hours with occasional stirring. The resulting mixture was first filtered through a clean cheesecloth and subsequently through Whatman No. 1 filter paper to obtain a clear filtrate. The filtrate was concentrated to dryness under reduced pressure using a rotary evaporator. The dried crude extract was weighed, and the percentage yield was calculated relative to the initial weight of the powdered stem bark. The extract was stored in an airtight container and kept refrigerated until required for further analysis.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eVacuum Liquid Chromatography\u003cbr\u003e\u003c/strong\u003eForty grams (40 g) of the crude extract of Caesalpinia pulcherrima stem bark was thoroughly adsorbed onto silica gel and mixed until a free-flowing powder was obtained. The dry-packed sample was subjected to vacuum liquid chromatography using silica gel as the stationary phase. Elution was carried out sequentially with solvent systems of increasing polarity to obtain different fractions. The solvent systems used in the analysis include 100% n-hexane, 50% n-hexane and 50% ethyl acetate solution, 100% ethyl acetate, 50% methanol and 50% ethyl acetate solution, and 100% methanol. Each fraction obtained was concentrated to dryness under reduced pressure using a rotary evaporator. The resulting dried fractions were stored in airtight containers and kept refrigerated until required for further analysis\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eExperimental Animals\u003cbr\u003e\u003c/strong\u003eSwiss albino mice of either sex, weighing between 20 and 30 g, were obtained from the animal house of the Faculty of Pharmacy, University of Benin, Nigeria, and used for the study. The animals were housed in clean plastic cages at room temperature under a naturally illuminated environment. They were allowed to acclimatize to laboratory conditions for four weeks prior to the commencement of the experiment. The mice were fed with a standard pellet diet and had free access to clean drinking water \u003cem\u003ead libitum\u003c/em\u003e. All experimental procedures were carried out in accordance with the National Institutes of Health (NIH) Guide for the Care and Use of Laboratory Animals.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePreparation of Giemsa Solution (Stock Giemsa)\u003c/strong\u003e\u0026nbsp;\u003cbr\u003e\u0026nbsp;Three point five grams (3.5 g) of solid Giemsa stain was added to a mixture of 250 mL of methanol and 250 mL of glycerol in a dark reagent bottle. The mixture was shaken vigorously to ensure proper dissolution and then stored in a cupboard at room temperature for seven days to allow complete maturation before use in the analysis.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePreparation of Phosphate Buffer Saline (PBS)\u003cbr\u003e\u003c/strong\u003e1.09g of disodium hydrogen phosphate and 0.32 g of sodium dihydrogen phosphate were dissolved in 100 mL of distilled water with continuous shaking. The pH of the solution was adjusted to 7.2 by the dropwise addition of 0.1 M sodium hydroxide solution. The buffer was then made up to volume, mixed thoroughly, and stored at room temperature until required.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eParasite Inoculation\u0026nbsp;\u003cbr\u003e\u003c/strong\u003eChloroquine sensitive \u003cem\u003eplasmodium berghei\u0026nbsp;\u003c/em\u003e(NK65) was obtained from the National Institute of Medical Research (NIMR), Lagos, Nigeria. Each mouse used in the experiment was infected intraperitoneally with 0.1ml of infected blood containing about 1\u0026times; 10\u003csup\u003e7\u0026nbsp;\u003c/sup\u003eparasitized red blood cells (PRBC).\u003c/p\u003e\n\u003cp\u003eIn a normal, unaffected mouse, the number of red blood cells in 1ml of blood is approximately 5\u0026times;10\u003csup\u003e8\u003c/sup\u003e, while in an infected mouse, the number of red blood cells in 1ml of blood is reduced to 3\u0026times;10\u003csup\u003e8\u003c/sup\u003e. This 1ml of parasitised red blood cell (containing 3\u0026times;10\u003csup\u003e8\u003c/sup\u003e RBC) was diluted with 3ml of phosphate buffer saline to give;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"https://myfiles.space/user_files/58895_8739fc6c57c1c19a/58895_custom_files/img1771491827.png\" width=\"441\" height=\"143\"\u003e\u003c/p\u003e\n\u003cp\u003eTherefore, scaling down the volume by a factor of 10, this will give;\u003c/p\u003e\n\u003cp\u003e1\u0026times;10\u003csup\u003e7\u003c/sup\u003e PRBC in 0.1ml of blood. It is this quantity of 1\u0026times;10\u003csup\u003e7\u0026nbsp;\u003c/sup\u003ePRBC that was introduced into the mouse as 0.1ml.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSample Digestion\u003c/strong\u003e\u003cbr\u003eOne gram (1.0 g) of the powdered stem of \u003cem\u003eCaesalpinia pulcherrima\u003c/em\u003e was accurately weighed into a digestion flask. Ten millilitres (10 mL) of perchloric acid (HClO₄) and 10 mL of nitric acid (HNO₃) were carefully added in a fume cupboard. The contents were gently swirled and heated under the fume cupboard for approximately 10 minutes until the evolution of brown nitrogen dioxide (NO₂) fumes was observed, indicating oxidation of the organic matter. The digest was then allowed to cool to room temperature, filtered, and quantitatively transferred into a 50 mL volumetric flask. The filtrate was diluted to the 50 mL mark with distilled water and mixed thoroughly. The digestion procedure was carried out in triplicate, including a reagent blank, and the resulting solutions were analysed for heavy metal content using an Atomic Absorption Spectrophotometer (AAS)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEvaluation of the Suppressive Activity of Extract (Peter\u0026rsquo;s 4-Days Test)\u003cbr\u003e\u003c/strong\u003eThe suppressive antimalarial activity of the stem bark extract of \u003cem\u003eCaesalpinia pulcherrima\u003c/em\u003e was evaluated using the standard 4-day suppressive test described by Knight and Peters (1980). On day one (D1), twenty-five Swiss albino mice were inoculated intraperitoneally with chloroquine-sensitive \u003cem\u003ePlasmodium berghei berghei\u003c/em\u003e-infected red blood cells. The animals were randomly assigned to five groups (A\u0026ndash;E) of five mice each, based on body weight. Treatments were administered once daily for four consecutive days (D1\u0026ndash;D4) between 8:00 pm and 9:00 pm.\u003c/p\u003e\n\u003cp\u003eGroup A served as the negative control and received no treatment. Groups B, C, and D were administered the stem bark extract orally at doses of 200, 400, and 800 mg/kg body weight, respectively. Group E served as the positive control and received chloroquine at a dose of 5 mg/kg body weight orally.\u003c/p\u003e\n\u003cp\u003eFrom day five (D5) to day eight (D8), blood samples were collected from the tail vein of each mouse for parasitological analysis. Thick and thin blood smears were prepared on clean glass slides, fixed with methanol, and stained with 4% Giemsa solution. After 45 minutes, the slides were rinsed with distilled water and allowed to air-dry. Parasitological examination was carried out using a light microscope, and parasitaemia was determined by counting parasitised red blood cells (PRBCs) and total red blood cells (RBCs) in ten different microscopic fields.\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"https://myfiles.space/user_files/58895_8739fc6c57c1c19a/58895_custom_files/img1771491933.png\" width=\"695\" height=\"487\"\u003e\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e"},{"header":"Results and Discussion","content":"\u003cp\u003eResults and Discussion The results obtained from the in vivo anti-plasmodia studies, and elemental analysis of the extract from the stem bark of C. pulcherrima are shown in Tables 1, 2 and 3 below\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePercentage yield of the extract\u003c/strong\u003e\u0026nbsp;\u003cbr\u003e\u0026nbsp;The percentage yield of the stem bark extract of C. pulcherrima obtained was 18.98%.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eComparison of %parasitaemia of the Stem Bark extract of C. pulcherrima and standard drug (chloroquine)\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAntimalarial activity of the stem bark extract of C. pulcherrima\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe stem bark extract of \u003cem\u003eCaesalpinia pulcherrima\u003c/em\u003e demonstrated significant, dose-dependent antimalarial activity against chloroquine-sensitive \u003cem\u003ePlasmodium berghei\u003c/em\u003e in Swiss albino mice, as reflected by percentage chemosuppression and mean survival time (Table 3). The extract at 200, 400, and 800 mg/kg produced progressive parasitaemia suppression from 45.32% to 63.29% on day 5, with corresponding increases in mean survival time from 17 to 26 days, compared to 14 days in the untreated control. The highest dose (800 mg/kg) exhibited the greatest chemosuppressive effect, confirming a clear dose-response relationship. Although chloroquine (5 mg/kg) showed superior suppression (86.22\u0026ndash;95.22%) and survival (28 \u0026plusmn; 0.45 days), the extract\u0026rsquo;s activity indicates substantial antiplasmodial potential.\u003c/p\u003e\n\u003cp\u003eThe observed effect may result from bioactive phytochemicals, such as flavonoids, alkaloids, and tannins, which are known to interfere with the intraerythrocytic development of \u003cem\u003ePlasmodium\u003c/em\u003e species. Additionally, the elemental composition of the stem bark, including iron, copper, calcium, and sodium, may support haematological and physiological functions during infection, potentially enhancing host resilience and contributing to prolonged survival. These findings corroborate traditional use of \u003cem\u003eC. pulcherrima\u003c/em\u003e for malaria treatment and suggest that the stem bark extract could serve as a complementary or alternative antimalarial agent, particularly in areas where access to conventional drugs is limited.\u003c/p\u003e\n\u003cp\u003eThe elemental analysis of \u003cem\u003eCaesalpinia pulcherrima\u003c/em\u003e leaves revealed the presence of essential metals\u0026mdash;sodium (11.73 \u0026plusmn; 0.17 ppm), calcium (9.33 \u0026plusmn; 3.46 ppm), iron (5.33 \u0026plusmn; 1.25 ppm), and copper (0.22 \u0026plusmn; 0.09 ppm)\u0026mdash;with toxic lead being undetectable, indicating the safety of the extract for medicinal use. These elements may contribute synergistically to the plant\u0026rsquo;s antimalarial activity. Iron supports erythropoiesis and helps counter malaria-induced anaemia, while copper enhances antioxidant defences, reducing oxidative stress caused by parasitic infection. Calcium and sodium play a crucial role in maintaining erythrocyte stability and overall physiological homeostasis, which can enhance the delivery and efficacy of bioactive compounds. The absence of lead ensures no additional haematological or toxicological risk. Therefore, the combination of bioactive phytochemicals and supportive trace elements likely underpins the observed dose-dependent parasitemia suppression, highlighting both the pharmacological potential and nutritional value of \u003cem\u003eC. pulcherrima\u003c/em\u003e in traditional malaria treatment.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe study found that the stem bark extract of Caesalpinia pulcherrima shows significant antiplasmodial activity, although it is less effective than chloroquine. This activity may be linked to bioactive compounds such as alkaloids, flavonoids, saponins, and tannins previously reported in the plant. While the specific active molecules were not identified, their presence suggests a potential for inhibiting Plasmodium growth. The findings support the traditional use of this plant for malaria treatment in Nigeria and recommend further research on isolating and characterizing the active compounds to develop affordable, plant-based antimalarial therapies.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eThe study titled \u0026ldquo;Anti Plasmodial Activity and Elemental Analysis of the Stem Bark Extract of Caesalpinia pulcherrima\u0026quot; involved the use of Swiss albino mice (20\u0026ndash;30 g) of either sex obtained from the University of Benin, Edo State, Nigeria.\u003c/p\u003e\n\u003cp\u003eAll animal handling and experimental procedures were conducted in accordance with the NIH Guide for the Care and Use of Laboratory Animals. The animals were maintained under standard laboratory conditions, as described in the methodology section of the manuscript. Oversight for the use of laboratory animals was provided by the University of Benin, where the animals were sourced and handled in line with institutional practices for animal care and use.\u003c/p\u003e\u003cp\u003e \u003ch2\u003eConflict of interest\u003c/h2\u003e \u003cp\u003eThe authors declare no conflict of interest.\u003c/p\u003e \u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003ePinto, A. C., Silva, D. H. S., Bolzani, V. S., Lopes, N. P., and Epifanio, R. A. (2002). Natural products: Activity, challenges and perspectives. \u003cem\u003eQu\u0026iacute;mica Nova, 25\u003c/em\u003e, 45\u0026ndash;61.\u003c/li\u003e\n \u003cli\u003eNewman, D. J., and Cragg, G. M. (2007). Natural products as sources of new drugs over the last 25 years. \u003cem\u003eJournal of Natural Products, 70\u003c/em\u003e(3), 461\u0026ndash;477.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eCragg, G. M., and Newman, D. J. (2005). 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Artemisinin resistance in \u003cem\u003ePlasmodium falciparum\u003c/em\u003e malaria. \u003cem\u003eNew England Journal of Medicine, 361\u003c/em\u003e(5), 455\u0026ndash;467.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eOdugbemi, T., and Odunayo, A. (2006). \u003cem\u003eNature of medicinal plants from Nigeria\u003c/em\u003e. University of Lagos Press.\u003c/li\u003e\n \u003cli\u003eChatterjee, A., and Prakashi, S. (2006). \u003cem\u003eThe treatise on Indian medicinal plants\u003c/em\u003e. NISCAIR.\u003c/li\u003e\n \u003cli\u003eChiu, N. Y., and Chang, K. H. (1992). \u003cem\u003eThe illustrated plants of Taiwan\u003c/em\u003e (Vol. 3). SMC Publishing.\u003c/li\u003e\n \u003cli\u003eSofowora, A. (2008). \u003cem\u003eMedicinal plants and traditional medicine in Africa\u003c/em\u003e (3rd ed.). Spectrum Books.\u003c/li\u003e\n \u003cli\u003eAdebayo, J. O., and Krettli, A. U. (2011). Potential antimalarials from Nigerian plants: A review. \u003cem\u003eJournal of Ethnopharmacology, 133\u003c/em\u003e(2), 289\u0026ndash;302.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eChiang, L. C., Chiang, W., \u0026amp; Chang, M. Y. (2002). Antiviral activity of \u003cem\u003ePlantago major\u003c/em\u003e extracts and related compounds in vitro. \u003cem\u003eAntiviral Research, 55\u003c/em\u003e(1), 53\u0026ndash;62.\u003c/li\u003e\n \u003cli\u003eAli, M. S., Azhar, I., and Amtul, Z. (1999). Antimicrobial screening of some \u003cem\u003eCaesalpinia\u003c/em\u003e species. \u003cem\u003eFitoterapia, 70\u003c/em\u003e, 299\u0026ndash;304.\u003c/li\u003e\n \u003cli\u003eMswahili, M. E., Martin, G. L., Woo, J., Choi, G. J., and Jeong, Y. S. (2021). Antiplasmodial activity and cytotoxicity of medicinal plants traditionally used in malaria treatment. \u003cem\u003eBiomolecules, 11\u003c/em\u003e(12), Article 1750.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eChoukri, M., Abouabdillah, A., Bouabid, R., Abd-Elkader, O. H., Pacioglu, O., Boufahja, F., and Bourioug, M. (2022). Zn application through seed priming improves productivity and grain nutritional quality of silage corn. \u003cem\u003eSaudi Journal of Biological Sciences, 29\u003c/em\u003e(12), Article 103456.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eEjigu, Y. W., and Endalifer, B. L. (2023). \u003cem\u003eIn vitro anti‑plasmodial activity of three selected medicinal plants that are used in local traditional medicine in Amhara region of Ethiopia\u003c/em\u003e. \u003cstrong\u003eBMC Pharmacology and Toxicology, 24\u003c/strong\u003e, Article 30.\u003c/li\u003e\n \u003cli\u003eOgu, G. I., and Ekeanyanwu, R. C. (2010). Assessment of renal function of Nigerian children infected with \u003cem\u003ePlasmodium falciparum\u003c/em\u003e. \u003cem\u003eInternational Journal of Medicine and Medical Sciences, 2\u003c/em\u003e(9), 251\u0026ndash;255\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTables 1 to 3 are available in the Supplementary Files section.\u003c/p\u003e\n"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"University of Benin","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Caesalpinia pulcherrima, antiplasmodial, antimalaria, elemental composition, AAS, plant extraction","lastPublishedDoi":"10.21203/rs.3.rs-8831025/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8831025/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe antiplasmodial activity of Caesalpinia pulcherrima (Pride of Barbados), a plant traditionally used in south-western Nigeria for the treatment of malaria, was investigated in the search for new antimalarial agents. Stem bark extracts and fractions were evaluated for in vivo antimalarial activity and elemental composition. Fractionation of the extracts was carried out using vacuum liquid chromatography (VLC), while elemental analysis was conducted using atomic absorption spectrophotometry (AAS). Antimalarial activity was assessed against Plasmodium berghei berghei in albino mice (20\u0026ndash;30 g) using the 4-day suppressive test. Methanol\u0026ndash;ethyl acetate stem bark extracts administered at doses of 200, 400, and 800 mg/kg produced dose-dependent chemo-suppression. The 200 mg/kg extract showed suppressive activities of 45.32%, 52.67%, 47.90%, and 24.17%; the 400 mg/kg extract showed 57.74%, 56.36%, 51.51%, and 30.35%; while the 800 mg/kg extract exhibited 63.29%, 62.09%, 54.24%, and 39.91%. These effects were lower than those of the standard drug chloroquine (5 mg/kg), which produced suppressive activities of 95.22%, 91.73%, 88.97%, and 86.22%. The results demonstrate that C. pulcherrima stem bark possesses significant antiplasmodial (suppressive) activity, supporting its traditional use in malaria treatment.\u003c/p\u003e","manuscriptTitle":"Anti-Plasmodial Activity and Elemental Analysis of the Stem Bark Extract of Caesalpinia pulcherrima","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-19 09:10:21","doi":"10.21203/rs.3.rs-8831025/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"ebeeb527-132e-4856-bbc4-9285da954a9d","owner":[],"postedDate":"February 19th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":62590190,"name":"Medicinal Chemistry"}],"tags":[],"updatedAt":"2026-02-19T09:10:22+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-19 09:10:21","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8831025","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8831025","identity":"rs-8831025","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}