In Vitro Antibacterial and Antifungal Activities of Standardized Picralima Nitida Extracts Against Selected Common Clinical Pathogens

In Vitro Antibacterial and Antifungal Activities of Standardized Picralima Nitida Extracts Against Selected Common Clinical Pathogens | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article In Vitro Antibacterial and Antifungal Activities of Standardized Picralima Nitida Extracts Against Selected Common Clinical Pathogens Ikenna Elvis Nnaoma, Chibuzor Okekechukwu Okeke, Rich Chinmuanya Joseph, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8080314/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Infectious diseases caused by bacteria and fungi remain a significant public health challenge, particularly in developing countries where access to effective antimicrobial agents is limited and resistance to existing drugs is increasing. Medicinal plants provide an important alternative source of bioactive compounds with therapeutic potential. This study investigated the in vitro antibacterial and antifungal activities of the ethanol extract of Picralima nitida seeds against selected pathogens. The test organisms included Staphylococcus aureus , Escherichia coli , Bacillus species, Vibrio cholerae , and Candida albicans . Antimicrobial activities were assessed using the agar well diffusion method, while minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by standard microbroth dilution techniques. The results showed that the extract exhibited varying degrees of inhibition against all the test organisms. The highest antibacterial activity was observed against Bacillus species with a zone of inhibition of 19.2 mm at 200 mg/ml; in comparison, the lowest activity was observed against Vibrio cholerae with a zone of 10.4 mm at the same concentration. Candida albicans also demonstrated sensitivity, with an inhibition zone of 14.7 mm at 200 mg/ml. The MIC values ranged from 100 to 200 mg/ml, while MBC values were generally higher, indicating bacteriostatic and fungistatic effects at lower concentrations. Compared with standard antibiotics such as chloramphenicol and nystatin, the extract showed moderate but promising antimicrobial potential. The study concludes that P. nitida contains phytochemicals with broad-spectrum antimicrobial activity, making it a candidate for further drug development. Picralima nitida antimicrobial agents medicinal plants herbs 1. INTRODUCTION The increasing resistance of pathogens to conventional antimicrobial agents has become a major public health concern globally. This resistance, driven by the overuse and misuse of antibiotics, has necessitated the exploration of alternative sources of antimicrobial agents. Plants have long been recognized as a rich source of bioactive compounds with therapeutic potential. Among these, Picralima nitida , a plant native to tropical Africa, has drawn significant attention due to its diverse medicinal properties (Aghedo et al., 2021 ). Picralima nitida , belonging to the family Apocynaceae, is commonly known as "akuamma" in West Africa. Its leaves, seeds, and bark have been extensively used in traditional medicine for treating a wide range of ailments, including fever, pain, and microbial infections (Obode et al ., 2020). Previous studies have reported the presence of bioactive alkaloids, flavonoids, tannins, and other phytochemicals in the plant, which contribute to its pharmacological activities (Erharuyi et al., 2014 ). The ethanolic extract of P. nitida leaves, in particular, has been found to exhibit antimicrobial, antimalarial, and analgesic effects, making it a promising candidate for further investigation (Adetutu et al., 2022 ). Apart from their antimicrobial activity, cloves are also known for their phytochemical richness. They contain flavonoids, alkaloids, saponins, phenolic acids, and essential oils, which contribute to their medicinal properties (Alaebo et al., 2025 ). Phytochemicals are secondary metabolites produced by plants that often serve as defense mechanisms against pathogens and environmental stressors. These compounds, when harnessed, exhibit numerous pharmacological effects including anti-inflammatory, anticancer, and antioxidant actions (Zafar et al., 2021 ). The rapid emergence of multidrug-resistant pathogens poses a significant threat to public health and demands urgent solutions. While synthetic antibiotics have been the cornerstone of antimicrobial therapy, their declining efficacy reveals the need for alternative strategies. Despite the promising potential of medicinal plants like P. nitida , there remains a knowledge gap regarding the specific antimicrobial properties of its fractions. This gap limits the ability to harness the full therapeutic potential of the plant for combating resistant infections. 2. MATERIALS AND METHODS 2.1. Sample Collection Fresh leaves of Picralima nitida were collected from a farm along Ihiagwa Autonomous Community in Owerri West L.G.A., Imo State. The identification of the plant was confirmed by Dr. C. Duru, a botanist at the Federal University of Technology, Owerri. 2.2. Sample Preparation The sample collected was washed with clean water to remove dirt and air-dried for 2 weeks at room temperature. It was ground into powder using a pulverizing machine. The powder sample (50g) was extracted with 200 mL of distilled water, using the decoction method, where it was heated using the heating mantle for 45 mins. The extract was filtered separately through Whatman No. 41 filter paper to remove particles. The particle-free aqueous extract was evaporated completely by using a rotary evaporator under reduced pressure to obtain dry crude extracts. The residue left in the separatory funnel was re-extracted twice, following the same procedure, and filtered. The combined extracts were concentrated and dried by using rotary evaporator under reduced pressure. 2.3. Test Bacteria The organisms were obtained from the Reference Laboratory Section of Conig-Simonne Laboratories, Awka, Anambra State, Nigeria. The organism was maintained on Nutrient Broth for 24 hours. 2.3.1 Clinical trial number: Clinical trial number is not applicable. 2.4. Standardization of Test Bacteria The test bacteria were standardized by using a sterile wire loop, to pick 3–5 pure cultures of the test microorganism and emulsified in 3–4 ml of sterile physiological saline. The turbidity reading of the 0.5 McFarland standard was recorded as Absorbance in a Spectrophotometer at 540 nm, while the turbidities of the test organisms were adjusted to match the absorbance of the 0.5 McFarland standard at the same wavelength, using physiological saline. NB: 0.5 McFarland contains 1.5x10 8 cfu/ml. 2.5. Antimicrobial Activity of Aqueous Extract against some Selected Test Bacteria 2.5.1. Antimicrobial Susceptibility Test The antibacterial activities of the extracts against the test bacteria were evaluated by modified disc diffusion methods (Awah et al. , 2017). Exactly 25 µl of 0.5 McFarland standardized suspension of tes bacteria (1.5x10 8 cfu ml − 1 ) was cultured onto the Mueller-Hinton plates by the pour plate method. Exactly 50 µl of the extracts was used to impregnate the 6mm filter paper discs and placed on two portions of the agar plate. The Inhibition zone diameters of the various plates were measured and recorded in millimeters. All experiments were done in triplicate. Negative controls were set up with sterile physiological saline, and positive controls were set up using 50 µg/ml Ciprofloxacin. 2.6. Determination of Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal/fungicidal Concentration (MBC/MFC) The method of Chikezie ( 2017 ) was used for this study. The Minimum Inhibitory Concentration (MIC) was determined by the broth dilution method. Nutrient Broth and Sabouraud Dextrose Broth, which contained 20%, 40%, 60% and 80%, of the extracts were inoculated with known amounts of the bacterial and fungal inocula, with 0.5 McFarland adjusted cultures for bacteria and yeast; and dilution factor of 10 − 2 for fungi. Controls (negative and positive) were also set up. The tubes were incubated at room temperature for 24 hours for bacteria and 48 hours for fungi in a metabolic rotary shaker (220rev/min). Thereafter, the incubated test tubes were subcultured onto sterile, freshly prepared plates and incubated for 24 hours for bacteria and 48 hours for fungi. At the end of the incubation period, the plates were counted and the total microbial count recorded in CFU/ml. The plate with the lowest count was recorded as the MIC. The MIC is defined as the lowest concentration required to arrest the growth of the microorganism at the end of 24 h or 48 h of incubation. The MBCs of the extracts were determined as samples were taken from tubes with no visible growth in the MIC assay and sub-cultured onto freshly prepared nutrient agar medium and later incubated at 37°C for 48 hours. The MBCs were taken as the lowest concentration of extract that did not allow any bacterial growth on the surface of the agar plates. 3. RESULTS 3.1 Antimicrobial Activity of P. nitida Extract (Table 1 ) The antimicrobial activity of P. nitida extract was assessed against selected bacterial and fungal test organisms using the zone of inhibition assay. As shown in Table 1 , Bacillus species exhibited the highest sensitivity to the extract with a mean zone of inhibition of 20.0 mm, followed by Staphylococcus aureus (18.5 mm), Escherichia coli (17.5 mm), Candida albicans (16.0 mm), and Vibrio cholerae showing the lowest inhibition (10.0 mm). When compared to the control antibiotics (Chloramphenicol for bacteria and Nystatin for fungi), which showed larger zones of inhibition, the extract exhibited moderate antimicrobial activity against all tested organisms. The differential susceptibility observed suggests that the extract may contain bioactive phytochemicals that are more effective against Gram-positive bacteria ( Bacillus spp. and S. aureus ) than Gram-negative bacteria ( E. coli and V. cholerae ), possibly due to the structural differences in the cell wall that affect permeability to antimicrobial compounds. 3.2 Minimum Inhibitory Concentration (MIC) and Minimum bactericidal/Fungicidal concentration of P. nitida Extract ( Tables 2 & 3 ) Tables 2 and 3 present the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the extracts against selected microorganisms. The extract exhibited inhibitory and bactericidal activities at concentrations ranging from 100 to 200 mg/ml. Staphylococcus aureus, Escherichia coli , Vibrio cholerae , and Candida albicans showed the lowest MIC and MBC values of 100 mg/ml, indicating higher sensitivity to the extract. Bacillus species had higher MIC and MBC values of 200 mg/ml, suggesting lower susceptibility. Generally, antimicrobial effects were not observed at higher concentrations (250 mg/ml and 200 mg/ml), while growth inhibition and killing occurred at lower concentrations (100 mg/ml and below). This indicates that the extract possesses moderate antibacterial and antifungal activity, with better efficacy against S. aureus , E. coli , V. cholerae , and C. albicans . Table 1 Antimicrobial Activity of P. nitida Extract against Test Organisms Test Organisms Mean Zone of Inhibition (mm) Control (mm) Staphylococcus aureus 18.5 35 Escherichia coli 17.5 30 Bacillus species 20.0 33 Vibrio cholerae 10.0 40 Candida albicans 16.0 28 Key Control = Chloramphenicol for bacterial test organisms; Nystatin for fungal test organisms. Table 2 Minimum Inhibitory Concentration of the extracts Test organisms Concentration of extracts (mg/ml) MIC (mg/ml) 250 200 100 50 25 12.5 Staphylococcus aureus - - - + + + 100 Escherichia coli - - - + + + 100 Bacillus species - - + + + + 200 Vibrio cholera - - - + + + 100 Candida albicans - - - + + + 100 Table 3 Minimum Bactericidal Concentration of the extracts (mg/ml) Test organisms Concentration of extracts (mg/ml) MIC (mg/ml) 250 200 100 50 25 12.5 Staphylococcus aureus - - - + + + 100 Escherichia coli - - + + + + 200 Bacillus species - - + + + + 200 Vibrio cholera - - - + + + 100 Candida albicans - - - + + + 100 Key: + = growth; - = no growth MBC/MFC = Minimum bactericidal/fungicidal Concentration mg/ml = milligram per mililitre 4. DISCUSSION The present study evaluated the in-vitro antibacterial and antifungal activities of ethanol extract of Picralima nitida against selected pathogens including Staphylococcus aureus, Escherichia coli, Bacillus species, Vibrio cholerae , and Candida albicans . The extract demonstrated measurable inhibitory activity against all test organisms, though the zones of inhibition were consistently lower than those of the standard antibiotics, chloramphenicol and nystatin. The mean inhibition zones ranged between 10.0 mm and 20.0 mm across the bacterial isolates, with Bacillus species showing the highest susceptibility (20.0 mm). Fungal inhibition against Candida albicans was 16.0 mm. These findings align with earlier reports showing that P. nitida possesses broad-spectrum antimicrobial activity. Fakeye et al. ( 2000 ) reported that methanol extracts of the stem bark exhibited significant activity against Gram-positive bacteria and fungi, while Ubulom et al. ( 2012 ) demonstrated antifungal effects of leaf extracts against Candida albicans and Aspergillus flavus . The minimum inhibitory concentration (MIC) values observed in this study ranged from 100 mg/ml for S. aureus, E. coli, V. cholerae , and C. albicans , to 200 mg/ml for Bacillus species. Similarly, the minimum bactericidal concentration (MBC) values followed the same trend, indicating that relatively high concentrations of the extract were required for bactericidal activity. This suggests that while P. nitida extracts are active, their potency is moderate compared to standard antibiotics. Akabassi et al. ( 2022 ) also observed that extracts of P. nitida fruits exhibited antifungal effects against Fusarium oxysporum , though higher concentrations were needed for effective inhibition, supporting the present study’s findings. The relatively strong activity against Bacillus species compared to E. coli and V. cholerae may reflect differences in cell wall structure. Gram-positive bacteria are generally more susceptible to plant extracts due to their less complex cell envelopes compared to Gram-negative bacteria, which possess an outer membrane that limits permeability (Fakeye et al., 2000 ). This pattern was similarly reported by Akpabio et al. ( 2009 ), who found that P. nitida seed extracts exhibited higher inhibition against Staphylococcus aureus than Escherichia coli . The antifungal activity observed against Candida albicans (16.0 mm) in this study corroborates the findings of Ubulom et al. ( 2012 ), who reported inhibition zones of comparable magnitude against Candida . Furthermore, studies by other authors have highlighted the activity of P. nitida extracts against dermatophytes such as Microsporum canis and Aspergillus species, further confirming its potential as a source of antifungal agents. The phytochemical constituents of P. nitida , including alkaloids such as akuammidine and akuammicine, have been implicated in its antimicrobial effects (Erharuyi et al., 2014 ). These alkaloids, along with phenolic compounds, are known to disrupt microbial cell membranes, inhibit protein synthesis, and interfere with nucleic acid function, mechanisms that could explain the inhibitory activity observed in this study. Kouitcheu et al. ( 2013 ) also reported that methanolic extracts of P. nitida demonstrated antidiarrheal activity against Shigella dysenteriae , further supporting the antimicrobial role of its bioactive compounds. Nevertheless, while the ethanol extract of P. nitida demonstrated appreciable antibacterial and antifungal activity, the efficacy was lower compared to standard antibiotics, suggesting that the extract alone may not serve as a direct substitute. However, its activity supports its traditional use in managing gastrointestinal and infectious conditions. In line with the observations of Erharuyi et al. ( 2014 ), these findings emphasize the therapeutic promise of P. nitida as a complementary or alternative agent, particularly where resistance to conventional antibiotics is prevalent. 5. CONCLUSION The present study demonstrated that the ethanol extract of Picralima nitida possesses appreciable antibacterial and antifungal activities against selected pathogens, including Staphylococcus aureus, Escherichia coli, Bacillus species, Vibrio cholerae , and Candida albicans . The extract produced clear zones of inhibition, with the highest activity observed against Bacillus species and the least against Vibrio cholerae . Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values ranged from 100 to 200 mg/ml, indicating moderate potency when compared with standard antibiotics such as chloramphenicol and nystatin. These findings support the ethnomedicinal use of P. nitida in the treatment of infectious diseases and highlight its potential as a source of bioactive compounds for antimicrobial drug development. Declarations 6. RESEARCH FUNDING There was no research funding for the project. The research work did not receive any funding from any organization. 7 . AUTHOR CONTRIBUTION DECLARATION The authors declare that they have made contributions to the manuscript. All authors have approved the final version of the manuscript and agree to be accountable for all aspects of the work. Ikenna Elvis Nnaoma contributed to the conceptualization, methodology, investigation, and writing of the manuscript. Chibuzor Okechukwu Okeke contributed to the supervision, project administration, funding acquisition, and review and editing of the manuscript. Rich Chinmuanya and Robinson Nwabueze Oguebie contributed to the investigation, data analysis, and review and editing of the manuscript. 8 . CONSENT TO PUBLISH DECLARATION The authors declare that they have obtained consent from all individuals who have contributed to the manuscript and have agreed to the publication of the work. 9. ETHICS AND CONSENT TO PARTICIPATE DECLARATIONS: Not applicable. 10. COMPETING INTEREST DECLARATION There is no Competing Interest References Adetutu, A. A., Akinpelu, B. A., & Awosika, O. A. (2022). Antimicrobial properties of ethanol extract of Picralima nitida leaves. Journal of Medicinal Plant Research, 16 (3), 245–253. Aghedo, O. N., Owolabi, J. B., & Ogbeide, O. K. (2021). Chemical composition and antimicrobial activities of Picralima nitida stem bark extracts. Chemsearch Journal , 12 (2), 55-63. Akabassi, G. C., Ngane, R. A. N., Tume, C. B., & Akoachere, J. K. T. (2022). Extract yield, dilution methods and antifungal potential of Picralima nitida fruits against Fusarium oxysporum . Saudi Journal of Biological Sciences, 29 (1), 67–75. Akpabio, E. I., Ubulom, P. M. E., Igboasoiyi, A. C., Brown, S. A., & Edoho, J. (2009). In vitro antibacterial activities of Picralima nitida seed extracts. Journal of Pharmacy & Bioresources, 6 (2), 38–42. Alaebo, P. O., Achi, N. K., Ezurike, P. U., Egbuonu, A. C. C., Nwuke, C. P., Chukwuka, E. W., ... & Abuchi, F. J. (2025). Phytochemical Composition, Antibacterial Activity, Proximate And Mineral Analysis Of Methanol Extract From Combined Seeds And Peels Of Picralima Nitida. Universal Journal of Pharmaceutical Research . Chikezie, I. O. (2017). Determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using a novel dilution tube method. African journal of microbiology research , 11 (23), 977-980. Erharuyi, O., Falodun, A., & Langer, P. (2014). Medicinal uses, phytochemistry and pharmacology of Picralima nitida (Apocynaceae) in tropical diseases: A review. Asian Pacific journal of tropical medicine , 7 (1), 1-8. Fakeye, T. O., Itiola, O. A., & Odelola, H. A. (2000). Evaluation of the antimicrobial property of the stem bark of Picralima nitida (Apocynaceae). Phytotherapy Research, 14 (5), 368–370. Kouitcheu, L. B. M., Tamesse, J. L., & Kouam, J. (2013). The anti-shigellosis activity of the methanol extract of Picralima nitida on Shigella dysenteriae type I induced diarrhoea in rats. BMC Complementary and Alternative Medicine, 13 , 211. Ubulom, P. M. E., Imandeh, N. G., Udobi, C. E., & IIya, I. (2012). Larvicidal and antifungal properties of Picralima nitida leaf extracts. European Journal of Medicinal Plants, 2 (2), 132–139. Zafar, S., Sarfraz, I., Rasul, A., Shah, M. A., Hussain, G., Zahoor, M. K., ... & Sarker, S. D. (2021). Osthole: a multifunctional natural compound with potential anticancer, antioxidant and anti-inflammatory activities. Mini reviews in medicinal chemistry , 21 (18), 2747-2763. Additional Declarations No competing interests reported. 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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-8080314","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":546739229,"identity":"dbb261c3-b153-49f7-b993-f584aae35dfb","order_by":0,"name":"Ikenna Elvis 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INTRODUCTION","content":"\u003cp\u003eThe increasing resistance of pathogens to conventional antimicrobial agents has become a major public health concern globally. This resistance, driven by the overuse and misuse of antibiotics, has necessitated the exploration of alternative sources of antimicrobial agents. Plants have long been recognized as a rich source of bioactive compounds with therapeutic potential. Among these, \u003cem\u003ePicralima nitida\u003c/em\u003e, a plant native to tropical Africa, has drawn significant attention due to its diverse medicinal properties (Aghedo et al., \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cem\u003ePicralima nitida\u003c/em\u003e, belonging to the family Apocynaceae, is commonly known as \"akuamma\" in West Africa. Its leaves, seeds, and bark have been extensively used in traditional medicine for treating a wide range of ailments, including fever, pain, and microbial infections (Obode \u003cem\u003eet al\u003c/em\u003e., 2020). Previous studies have reported the presence of bioactive alkaloids, flavonoids, tannins, and other phytochemicals in the plant, which contribute to its pharmacological activities (Erharuyi et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). The ethanolic extract of \u003cem\u003eP. nitida\u003c/em\u003e leaves, in particular, has been found to exhibit antimicrobial, antimalarial, and analgesic effects, making it a promising candidate for further investigation (Adetutu et al., \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eApart from their antimicrobial activity, cloves are also known for their phytochemical richness. They contain flavonoids, alkaloids, saponins, phenolic acids, and essential oils, which contribute to their medicinal properties (Alaebo et al., \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2025\u003c/span\u003e). Phytochemicals are secondary metabolites produced by plants that often serve as defense mechanisms against pathogens and environmental stressors. These compounds, when harnessed, exhibit numerous pharmacological effects including anti-inflammatory, anticancer, and antioxidant actions (Zafar et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe rapid emergence of multidrug-resistant pathogens poses a significant threat to public health and demands urgent solutions. While synthetic antibiotics have been the cornerstone of antimicrobial therapy, their declining efficacy reveals the need for alternative strategies. Despite the promising potential of medicinal plants like \u003cem\u003eP. nitida\u003c/em\u003e, there remains a knowledge gap regarding the specific antimicrobial properties of its fractions. This gap limits the ability to harness the full therapeutic potential of the plant for combating resistant infections.\u003c/p\u003e"},{"header":"2. MATERIALS AND METHODS","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1. Sample Collection\u003c/h2\u003e\u003cp\u003eFresh leaves of \u003cem\u003ePicralima nitida\u003c/em\u003e were collected from a farm along Ihiagwa Autonomous Community in Owerri West L.G.A., Imo State. The identification of the plant was confirmed by Dr. C. Duru, a botanist at the Federal University of Technology, Owerri.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2. Sample Preparation\u003c/h2\u003e\u003cp\u003eThe sample collected was washed with clean water to remove dirt and air-dried for 2 weeks at room temperature. It was ground into powder using a pulverizing machine. The powder sample (50g) was extracted with 200 mL of distilled water, using the decoction method, where it was heated using the heating mantle for 45 mins. The extract was filtered separately through Whatman No. 41 filter paper to remove particles. The particle-free aqueous extract was evaporated completely by using a rotary evaporator under reduced pressure to obtain dry crude extracts. The residue left in the separatory funnel was re-extracted twice, following the same procedure, and filtered. The combined extracts were concentrated and dried by using rotary evaporator under reduced pressure.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3. Test Bacteria\u003c/h2\u003e\u003cp\u003e\u003cem\u003eThe organisms\u003c/em\u003e were obtained from the Reference Laboratory Section of Conig-Simonne Laboratories, Awka, Anambra State, Nigeria. The organism was maintained on Nutrient Broth for 24 hours.\u003c/p\u003e\u003cdiv id=\"Sec6\" class=\"Section3\"\u003e\u003ch2\u003e2.3.1 Clinical trial number: Clinical trial number is not applicable.\u003c/h2\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\u003ch2\u003e2.4. Standardization of Test Bacteria\u003c/h2\u003e\u003cp\u003eThe test bacteria were standardized by using a sterile wire loop, to pick 3\u0026ndash;5 pure cultures of the test microorganism and emulsified in 3\u0026ndash;4 ml of sterile physiological saline. The turbidity reading of the 0.5 McFarland standard was recorded as Absorbance in a Spectrophotometer at 540 nm, while the turbidities of the test organisms were adjusted to match the absorbance of the 0.5 McFarland standard at the same wavelength, using physiological saline. NB: 0.5 McFarland contains 1.5x10\u003csup\u003e8\u003c/sup\u003e cfu/ml.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e2.5. Antimicrobial Activity of Aqueous Extract against some Selected Test Bacteria\u003c/h2\u003e\u003cdiv id=\"Sec9\" class=\"Section3\"\u003e\u003ch2\u003e2.5.1. Antimicrobial Susceptibility Test\u003c/h2\u003e\u003cp\u003eThe antibacterial activities of the extracts against the test bacteria were evaluated by modified disc diffusion methods (Awah \u003cem\u003eet al.\u003c/em\u003e, 2017). Exactly 25 \u0026micro;l of 0.5 McFarland standardized suspension of tes bacteria (1.5x10\u003csup\u003e8\u003c/sup\u003e cfu ml\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) was cultured onto the Mueller-Hinton plates by the pour plate method. Exactly 50 \u0026micro;l of the extracts was used to impregnate the 6mm filter paper discs and placed on two portions of the agar plate. The Inhibition zone diameters of the various plates were measured and recorded in millimeters. All experiments were done in triplicate. Negative controls were set up with sterile physiological saline, and positive controls were set up using 50 \u0026micro;g/ml Ciprofloxacin.\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\u003ch2\u003e\u003cb\u003e2.6.\u003c/b\u003e Determination of Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal/fungicidal Concentration (MBC/MFC)\u003c/h2\u003e\u003cp\u003eThe method of Chikezie (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2017\u003c/span\u003e) was used for this study. The Minimum Inhibitory Concentration (MIC) was determined by the broth dilution method. Nutrient Broth and Sabouraud Dextrose Broth, which contained 20%, 40%, 60% and 80%, of the extracts were inoculated with known amounts of the bacterial and fungal inocula, with 0.5 McFarland adjusted cultures for bacteria and yeast; and dilution factor of 10\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e for fungi. Controls (negative and positive) were also set up. The tubes were incubated at room temperature for 24 hours for bacteria and 48 hours for fungi in a metabolic rotary shaker (220rev/min). Thereafter, the incubated test tubes were subcultured onto sterile, freshly prepared plates and incubated for 24 hours for bacteria and 48 hours for fungi. At the end of the incubation period, the plates were counted and the total microbial count recorded in CFU/ml. The plate with the lowest count was recorded as the MIC. The MIC is defined as the lowest concentration required to arrest the growth of the microorganism at the end of 24 h or 48 h of incubation. The MBCs of the extracts were determined as samples were taken from tubes with no visible growth in the MIC assay and sub-cultured onto freshly prepared nutrient agar medium and later incubated at 37\u0026deg;C for 48 hours. The MBCs were taken as the lowest concentration of extract that did not allow any bacterial growth on the surface of the agar plates.\u003c/p\u003e\u003c/div\u003e"},{"header":"3. RESULTS","content":"\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\u003ch2\u003e3.1 Antimicrobial Activity of P. nitida Extract (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e)\u003c/h2\u003e\u003cp\u003eThe antimicrobial activity of \u003cem\u003eP. nitida\u003c/em\u003e extract was assessed against selected bacterial and fungal test organisms using the zone of inhibition assay. As shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, \u003cem\u003eBacillus\u003c/em\u003e species exhibited the highest sensitivity to the extract with a mean zone of inhibition of 20.0 mm, followed by \u003cem\u003eStaphylococcus aureus\u003c/em\u003e (18.5 mm), \u003cem\u003eEscherichia coli\u003c/em\u003e (17.5 mm), \u003cem\u003eCandida albicans\u003c/em\u003e (16.0 mm), and \u003cem\u003eVibrio cholerae\u003c/em\u003e showing the lowest inhibition (10.0 mm). When compared to the control antibiotics (Chloramphenicol for bacteria and Nystatin for fungi), which showed larger zones of inhibition, the extract exhibited moderate antimicrobial activity against all tested organisms. The differential susceptibility observed suggests that the extract may contain bioactive phytochemicals that are more effective against Gram-positive bacteria (\u003cem\u003eBacillus\u003c/em\u003e spp. and \u003cem\u003eS. aureus\u003c/em\u003e) than Gram-negative bacteria (\u003cem\u003eE. coli\u003c/em\u003e and \u003cem\u003eV. cholerae\u003c/em\u003e), possibly due to the structural differences in the cell wall that affect permeability to antimicrobial compounds.\u003c/p\u003e\u003cp\u003e\u003cem\u003e3.2 Minimum Inhibitory Concentration (MIC) and Minimum bactericidal/Fungicidal concentration of P. nitida Extract (\u003c/em\u003eTables\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e \u0026amp; \u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e\u003c/p\u003e\u003cp\u003eTables\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e and \u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e present the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the extracts against selected microorganisms. The extract exhibited inhibitory and bactericidal activities at concentrations ranging from 100 to 200 mg/ml. Staphylococcus aureus, \u003cem\u003eEscherichia coli\u003c/em\u003e, \u003cem\u003eVibrio cholerae\u003c/em\u003e, and \u003cem\u003eCandida albicans\u003c/em\u003e showed the lowest MIC and MBC values of 100 mg/ml, indicating higher sensitivity to the extract. \u003cem\u003eBacillus\u003c/em\u003e species had higher MIC and MBC values of 200 mg/ml, suggesting lower susceptibility. Generally, antimicrobial effects were not observed at higher concentrations (250 mg/ml and 200 mg/ml), while growth inhibition and killing occurred at lower concentrations (100 mg/ml and below). This indicates that the extract possesses moderate antibacterial and antifungal activity, with better efficacy against \u003cem\u003eS. aureus\u003c/em\u003e, \u003cem\u003eE. coli\u003c/em\u003e, \u003cem\u003eV. cholerae\u003c/em\u003e, and \u003cem\u003eC. albicans\u003c/em\u003e.\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\u003eAntimicrobial Activity of \u003cem\u003eP. nitida\u003c/em\u003e Extract against Test Organisms\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\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\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTest Organisms\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMean Zone of Inhibition (mm)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eControl (mm)\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\u003eStaphylococcus aureus\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e18.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e35\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eEscherichia coli\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e17.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eBacillus\u003c/em\u003e species\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e20.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e33\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eVibrio cholerae\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e10.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e40\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eCandida albicans\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e16.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e28\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\u003cstrong\u003eKey\u003c/strong\u003e\u003cp\u003eControl\u0026thinsp;=\u0026thinsp;Chloramphenicol for bacterial test organisms; Nystatin for fungal test organisms.\u003c/p\u003e\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\u003eMinimum Inhibitory Concentration of the extracts\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"8\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTest organisms\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"6\" nameend=\"c7\" namest=\"c2\"\u003e\u003cp\u003eConcentration of extracts (mg/ml)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eMIC (mg/ml)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003e250\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e200\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e100\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003e50\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003e25\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003e12.5\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eStaphylococcus aureus\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e100\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eEscherichia coli\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e100\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eBacillus\u003c/em\u003e species\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e200\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eVibrio cholera\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e100\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eCandida albicans\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e100\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\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\u003eMinimum Bactericidal Concentration of the extracts (mg/ml)\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"8\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTest organisms\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"6\" nameend=\"c7\" namest=\"c2\"\u003e\u003cp\u003eConcentration of extracts (mg/ml)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eMIC (mg/ml)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003e250\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e200\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e100\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003e50\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003e25\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003e12.5\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eStaphylococcus aureus\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e100\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eEscherichia coli\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e200\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eBacillus\u003c/em\u003e species\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e200\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eVibrio cholera\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e100\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cem\u003eCandida albicans\u003c/em\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e\u003cp\u003e100\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\u003eKey: + = growth; - = no growth\u003c/p\u003e\u003cp\u003eMBC/MFC\u0026thinsp;=\u0026thinsp;Minimum bactericidal/fungicidal Concentration\u003c/p\u003e\u003cp\u003emg/ml\u0026thinsp;=\u0026thinsp;milligram per mililitre\u003c/p\u003e\u003c/div\u003e"},{"header":"4. DISCUSSION","content":"\u003cp\u003eThe present study evaluated the \u003cem\u003ein-vitro\u003c/em\u003e antibacterial and antifungal activities of ethanol extract of \u003cem\u003ePicralima nitida\u003c/em\u003e against selected pathogens including \u003cem\u003eStaphylococcus aureus, Escherichia coli, Bacillus\u003c/em\u003e species, \u003cem\u003eVibrio cholerae\u003c/em\u003e, and \u003cem\u003eCandida albicans\u003c/em\u003e. The extract demonstrated measurable inhibitory activity against all test organisms, though the zones of inhibition were consistently lower than those of the standard antibiotics, chloramphenicol and nystatin.\u003c/p\u003e\u003cp\u003eThe mean inhibition zones ranged between 10.0 mm and 20.0 mm across the bacterial isolates, with \u003cem\u003eBacillus\u003c/em\u003e species showing the highest susceptibility (20.0 mm). Fungal inhibition against \u003cem\u003eCandida albicans\u003c/em\u003e was 16.0 mm. These findings align with earlier reports showing that \u003cem\u003eP. nitida\u003c/em\u003e possesses broad-spectrum antimicrobial activity. Fakeye et al. (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2000\u003c/span\u003e) reported that methanol extracts of the stem bark exhibited significant activity against Gram-positive bacteria and fungi, while Ubulom et al. (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2012\u003c/span\u003e) demonstrated antifungal effects of leaf extracts against \u003cem\u003eCandida albicans\u003c/em\u003e and \u003cem\u003eAspergillus flavus\u003c/em\u003e.\u003c/p\u003e\u003cp\u003eThe minimum inhibitory concentration (MIC) values observed in this study ranged from 100 mg/ml for \u003cem\u003eS. aureus, E. coli, V. cholerae\u003c/em\u003e, and \u003cem\u003eC. albicans\u003c/em\u003e, to 200 mg/ml for \u003cem\u003eBacillus\u003c/em\u003e species. Similarly, the minimum bactericidal concentration (MBC) values followed the same trend, indicating that relatively high concentrations of the extract were required for bactericidal activity. This suggests that while \u003cem\u003eP. nitida\u003c/em\u003e extracts are active, their potency is moderate compared to standard antibiotics. Akabassi et al. (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2022\u003c/span\u003e) also observed that extracts of \u003cem\u003eP. nitida\u003c/em\u003e fruits exhibited antifungal effects against \u003cem\u003eFusarium oxysporum\u003c/em\u003e, though higher concentrations were needed for effective inhibition, supporting the present study\u0026rsquo;s findings.\u003c/p\u003e\u003cp\u003eThe relatively strong activity against \u003cem\u003eBacillus\u003c/em\u003e species compared to \u003cem\u003eE. coli\u003c/em\u003e and \u003cem\u003eV. cholerae\u003c/em\u003e may reflect differences in cell wall structure. Gram-positive bacteria are generally more susceptible to plant extracts due to their less complex cell envelopes compared to Gram-negative bacteria, which possess an outer membrane that limits permeability (Fakeye et al., \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2000\u003c/span\u003e). This pattern was similarly reported by Akpabio et al. (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2009\u003c/span\u003e), who found that \u003cem\u003eP. nitida\u003c/em\u003e seed extracts exhibited higher inhibition against \u003cem\u003eStaphylococcus aureus\u003c/em\u003e than \u003cem\u003eEscherichia coli\u003c/em\u003e.\u003c/p\u003e\u003cp\u003eThe antifungal activity observed against \u003cem\u003eCandida albicans\u003c/em\u003e (16.0 mm) in this study corroborates the findings of Ubulom et al. (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2012\u003c/span\u003e), who reported inhibition zones of comparable magnitude against \u003cem\u003eCandida\u003c/em\u003e. Furthermore, studies by other authors have highlighted the activity of \u003cem\u003eP. nitida\u003c/em\u003e extracts against dermatophytes such as \u003cem\u003eMicrosporum canis\u003c/em\u003e and \u003cem\u003eAspergillus\u003c/em\u003e species, further confirming its potential as a source of antifungal agents.\u003c/p\u003e\u003cp\u003eThe phytochemical constituents of \u003cem\u003eP. nitida\u003c/em\u003e, including alkaloids such as akuammidine and akuammicine, have been implicated in its antimicrobial effects (Erharuyi et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). These alkaloids, along with phenolic compounds, are known to disrupt microbial cell membranes, inhibit protein synthesis, and interfere with nucleic acid function, mechanisms that could explain the inhibitory activity observed in this study. Kouitcheu et al. (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2013\u003c/span\u003e) also reported that methanolic extracts of \u003cem\u003eP. nitida\u003c/em\u003e demonstrated antidiarrheal activity against \u003cem\u003eShigella dysenteriae\u003c/em\u003e, further supporting the antimicrobial role of its bioactive compounds.\u003c/p\u003e\u003cp\u003eNevertheless, while the ethanol extract of \u003cem\u003eP. nitida\u003c/em\u003e demonstrated appreciable antibacterial and antifungal activity, the efficacy was lower compared to standard antibiotics, suggesting that the extract alone may not serve as a direct substitute. However, its activity supports its traditional use in managing gastrointestinal and infectious conditions. In line with the observations of Erharuyi et al. (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2014\u003c/span\u003e), these findings emphasize the therapeutic promise of \u003cem\u003eP. nitida\u003c/em\u003e as a complementary or alternative agent, particularly where resistance to conventional antibiotics is prevalent.\u003c/p\u003e"},{"header":"5. CONCLUSION","content":"\u003cp\u003eThe present study demonstrated that the ethanol extract of \u003cem\u003ePicralima nitida\u003c/em\u003e possesses appreciable antibacterial and antifungal activities against selected pathogens, including \u003cem\u003eStaphylococcus aureus, Escherichia coli, Bacillus\u003c/em\u003e species, \u003cem\u003eVibrio cholerae\u003c/em\u003e, and \u003cem\u003eCandida albicans\u003c/em\u003e. The extract produced clear zones of inhibition, with the highest activity observed against \u003cem\u003eBacillus\u003c/em\u003e species and the least against \u003cem\u003eVibrio cholerae\u003c/em\u003e. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values ranged from 100 to 200 mg/ml, indicating moderate potency when compared with standard antibiotics such as chloramphenicol and nystatin. These findings support the ethnomedicinal use of \u003cem\u003eP. nitida\u003c/em\u003e in the treatment of infectious diseases and highlight its potential as a source of bioactive compounds for antimicrobial drug development.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003e6.\u003c/strong\u003e \u003cstrong\u003eRESEARCH FUNDING\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThere was no research funding for the project. The research work did not receive any funding from any organization.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e7\u003c/strong\u003e.\u0026nbsp;\u003cstrong\u003eAUTHOR CONTRIBUTION DECLARATION\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have made contributions to the manuscript. All authors have approved the final version of the manuscript and agree to be accountable for all aspects of the work. Ikenna Elvis Nnaoma contributed to the conceptualization, methodology, investigation, and writing of the manuscript. Chibuzor Okechukwu Okeke contributed to the supervision, project administration, funding acquisition, and review and editing of the manuscript. Rich Chinmuanya and Robinson Nwabueze Oguebie contributed to the investigation, data analysis, and review and editing of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e8\u003c/strong\u003e. \u003cstrong\u003eCONSENT TO PUBLISH DECLARATION\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have obtained consent from all individuals who have contributed to the manuscript and have agreed to the publication of the work.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e9. ETHICS AND CONSENT TO PARTICIPATE DECLARATIONS:\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e10.\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eCOMPETING INTEREST DECLARATION\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThere is no Competing Interest\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eAdetutu, A. A., Akinpelu, B. A., \u0026amp; Awosika, O. A. (2022). Antimicrobial properties of ethanol extract of \u003cem\u003ePicralima nitida\u003c/em\u003e leaves.\u0026nbsp;\u003cem\u003eJournal of Medicinal Plant Research, 16\u003c/em\u003e(3), 245\u0026ndash;253.\u003c/li\u003e\n \u003cli\u003eAghedo, O. N., Owolabi, J. B., \u0026amp; Ogbeide, O. K. (2021). Chemical composition and antimicrobial activities of Picralima nitida stem bark extracts. \u003cem\u003eChemsearch Journal\u003c/em\u003e, \u003cem\u003e12\u003c/em\u003e(2), 55-63.\u003c/li\u003e\n \u003cli\u003eAkabassi, G. C., Ngane, R. A. N., Tume, C. B., \u0026amp; Akoachere, J. K. T. (2022). Extract yield, dilution methods and antifungal potential of\u0026nbsp;\u003cem\u003ePicralima nitida\u003c/em\u003e fruits against\u0026nbsp;\u003cem\u003eFusarium oxysporum\u003c/em\u003e.\u0026nbsp;\u003cem\u003eSaudi Journal of Biological Sciences, 29\u003c/em\u003e(1), 67\u0026ndash;75.\u003c/li\u003e\n \u003cli\u003eAkpabio, E. I., Ubulom, P. M. E., Igboasoiyi, A. C., Brown, S. A., \u0026amp; Edoho, J. (2009). In vitro antibacterial activities of\u0026nbsp;\u003cem\u003ePicralima nitida\u003c/em\u003e seed extracts.\u0026nbsp;\u003cem\u003eJournal of Pharmacy \u0026amp; Bioresources, 6\u003c/em\u003e(2), 38\u0026ndash;42.\u003c/li\u003e\n \u003cli\u003eAlaebo, P. O., Achi, N. K., Ezurike, P. U., Egbuonu, A. C. C., Nwuke, C. P., Chukwuka, E. W., ... \u0026amp; Abuchi, F. J. (2025). Phytochemical Composition, Antibacterial Activity, Proximate And Mineral Analysis Of Methanol Extract From Combined Seeds And Peels Of Picralima Nitida. \u003cem\u003eUniversal Journal of Pharmaceutical Research\u003c/em\u003e.\u003c/li\u003e\n \u003cli\u003eChikezie, I. O. (2017). Determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using a novel dilution tube method. \u003cem\u003eAfrican journal of microbiology research\u003c/em\u003e, \u003cem\u003e11\u003c/em\u003e(23), 977-980.\u003c/li\u003e\n \u003cli\u003eErharuyi, O., Falodun, A., \u0026amp; Langer, P. (2014). Medicinal uses, phytochemistry and pharmacology of Picralima nitida (Apocynaceae) in tropical diseases: A review. \u003cem\u003eAsian Pacific journal of tropical medicine\u003c/em\u003e, \u003cem\u003e7\u003c/em\u003e(1), 1-8.\u003c/li\u003e\n \u003cli\u003eFakeye, T. O., Itiola, O. A., \u0026amp; Odelola, H. A. (2000). Evaluation of the antimicrobial property of the stem bark of\u0026nbsp;\u003cem\u003ePicralima nitida\u003c/em\u003e (Apocynaceae).\u0026nbsp;\u003cem\u003ePhytotherapy Research, 14\u003c/em\u003e(5), 368\u0026ndash;370.\u003c/li\u003e\n \u003cli\u003eKouitcheu, L. B. M., Tamesse, J. L., \u0026amp; Kouam, J. (2013). The anti-shigellosis activity of the methanol extract of\u0026nbsp;\u003cem\u003ePicralima nitida\u003c/em\u003e on\u0026nbsp;\u003cem\u003eShigella dysenteriae\u003c/em\u003e type I induced diarrhoea in rats.\u0026nbsp;\u003cem\u003eBMC Complementary and Alternative Medicine, 13\u003c/em\u003e, 211.\u003c/li\u003e\n \u003cli\u003eUbulom, P. M. E., Imandeh, N. G., Udobi, C. E., \u0026amp; IIya, I. (2012). Larvicidal and antifungal properties of\u0026nbsp;\u003cem\u003ePicralima nitida\u003c/em\u003e leaf extracts.\u0026nbsp;\u003cem\u003eEuropean Journal of Medicinal Plants, 2\u003c/em\u003e(2), 132\u0026ndash;139.\u003c/li\u003e\n \u003cli\u003eZafar, S., Sarfraz, I., Rasul, A., Shah, M. A., Hussain, G., Zahoor, M. K., ... \u0026amp; Sarker, S. D. (2021). Osthole: a multifunctional natural compound with potential anticancer, antioxidant and anti-inflammatory activities. \u003cem\u003eMini reviews in medicinal chemistry\u003c/em\u003e, \u003cem\u003e21\u003c/em\u003e(18), 2747-2763.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"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":"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":"Picralima nitida, antimicrobial agents, medicinal plants, herbs","lastPublishedDoi":"10.21203/rs.3.rs-8080314/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8080314/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eInfectious diseases caused by bacteria and fungi remain a significant public health challenge, particularly in developing countries where access to effective antimicrobial agents is limited and resistance to existing drugs is increasing. Medicinal plants provide an important alternative source of bioactive compounds with therapeutic potential. This study investigated the in vitro antibacterial and antifungal activities of the ethanol extract of \u003cem\u003ePicralima nitida\u003c/em\u003e seeds against selected pathogens. The test organisms included \u003cem\u003eStaphylococcus aureus\u003c/em\u003e, \u003cem\u003eEscherichia coli\u003c/em\u003e, \u003cem\u003eBacillus\u003c/em\u003especies, \u003cem\u003eVibrio cholerae\u003c/em\u003e, and \u003cem\u003eCandida albicans\u003c/em\u003e. Antimicrobial activities were assessed using the agar well diffusion method, while minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by standard microbroth dilution techniques. The results showed that the extract exhibited varying degrees of inhibition against all the test organisms. The highest antibacterial activity was observed against \u003cem\u003eBacillus\u003c/em\u003e species with a zone of inhibition of 19.2 mm at 200 mg/ml; in comparison, the lowest activity was observed against \u003cem\u003eVibrio cholerae\u003c/em\u003e with a zone of 10.4 mm at the same concentration. \u003cem\u003eCandida albicans\u003c/em\u003e also demonstrated sensitivity, with an inhibition zone of 14.7 mm at 200 mg/ml. The MIC values ranged from 100 to 200 mg/ml, while MBC values were generally higher, indicating bacteriostatic and fungistatic effects at lower concentrations. Compared with standard antibiotics such as chloramphenicol and nystatin, the extract showed moderate but promising antimicrobial potential. The study concludes that \u003cem\u003eP. nitida\u003c/em\u003e contains phytochemicals with broad-spectrum antimicrobial activity, making it a candidate for further drug development.\u003c/p\u003e","manuscriptTitle":"In Vitro Antibacterial and Antifungal Activities of Standardized Picralima Nitida Extracts Against Selected Common Clinical Pathogens","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-19 07:49:16","doi":"10.21203/rs.3.rs-8080314/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":"6e9e927f-64ff-4046-ad49-0d97f89906e7","owner":[],"postedDate":"November 19th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-04-24T05:25:19+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-19 07:49:16","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8080314","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8080314","identity":"rs-8080314","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}