The Journal of Phytopharmacology 2026; 15(1):1-12 ; DOI:10.31254/phyto.2026.15101
The antibacterial activities of Terminalia ivorensis A. Chev (Combretaceae) leaves against multidrug-resistant bacteria and its toxicity profile
Gloria A. Ayoola1 , Adebowale O. Adeluola2 , Abubakar S. Abdullahi1 , David B. Orojuekun1 , Oluwatosin O. Johnson1 , Modupe Ologunagba3 , David K. Adeyemi1 , Usman Abdulrahman2
1. Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Lagos, College of Medicine Campus, Idi-araba, Lagos, 100254, Nigeria
2. Department of Pharmaceutical Microbiology & Biotechnology, Faculty of Pharmacy, University of Lagos College of Medicine Campus, Idi-araba, Lagos, 100254, Nigeria
3. Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmacy, University of Lagos, College of Medicine Campus, Idi-araba, 100254, Lagos, Nigeria
*Author to whom correspondence should be addressed.
Received: 14th November, 2025 / Accepted: 13th March, 2026 / Published : 28th March, 2026
Background: Multidrug resistance (MDR) poses a significant global threat to healthcare. Terminalia ivorensis, a plant traditionally used in Africa, has been reported to possess antibacterial and protective properties. However, there is limited scientific evidence regarding its effectiveness against multidrug-resistant strains and its safety profile. This study was therefore conducted to address these knowledge gaps and to support the WHO Traditional Medicine Centre’s mission of developing safe, effective, and evidence-based plant-derived therapies. Objective: The objective of this study was to investigate the potential of T. ivorensis leaf extract as a safe and effective antibacterial agent against multidrug-resistant bacteria. Materials and Methods: T. ivorensis leaves were ethanol-extracted, phytochemically screened, and tested for antibacterial activity and toxicity using standard microbial assays and Organization for Economic Cooperation and Development (OECD) guidelines for animal studies. Multi-drug-resistant strain obtained from the Department of Pharmaceutical Microbiology, University of Lagos, previously profiled and validated for identity and antimicrobial susceptibility, was utilized in this study. Gram-negative isolates: Seven Extended β-lactamase-producing Klebsiella pneumoniae strains [Oga, N3, N24, OG 1(4), N19, Med 1(2), N14], one AmpC β-lactamase strain (Med 5(1)), one efflux pump active K. pneumoniae (OG 1(3)), and one Pseudomonas aeruginosa (PA 24) clinical isolate were used. Escherichia coli ATCC 25922 served as the drug-susceptible control. Gram-positive isolates: Included three oxacillin-resistant, carbapenemase-producing Staphylococcus aureus strains [ES 21, ES 44, MED4(2)], one carbapenemase-producing strain (ML 10), one oxacillin-resistant Staphylococcus lentus (ES 14), one Micrococcus spp. with efflux pump activity (ES 7), one Staphylococcus xylosus (ES 16), and one Enterococcus faecalis (EF 24). S. aureus ATCC 25923 was used as the control. Results: The 50% ethanol extract of T. ivorensis demonstrated concentration-dependent antibacterial activity against multidrug-resistant microorganisms, with inhibition zones ranging from 13.00 to 31.33 mm at concentrations of 100-400 mg/mL. The standard drug Levofloxacin exhibited bacterial inhibition zones ranging from 15.33 to 45.00 mm at concentrations of 6.25 to 50 µg/mL. While Levofloxacin showed strong activity against several strains, it was ineffective against certain K. pneumoniae EPA, K. pneumoniae ESBL producers, and S. xylosus ORSA. The extract exhibited minimum inhibitory concentrations (MIC) between 0.4-3.2?mg/mL, while levofloxacin showed ranges from 0.0156 to 8 µg/mL, and minimum bacterial concentrations (MBC), for the extract ranged from 0.8-25.6 mg/mL, compared to levofloxacin's 0.0156 to 8 µg/mL. Phytochemical analysis revealed the presence of alkaloids, tannins, phlobatannins, saponins, terpenoids, cardiac glycosides, reducing sugar, steroids, flavonoids, and phenols. The oral administration of the extracts at doses up to 2000 mg/kg showed no acute toxicity or adverse behavioural effects in mice over 14 days. Sub-acute treatment in rats for 28 days revealed no significant changes in body weight, haematological parameters, or liver function markers, except for a slight but significant increase in creatinine levels. The sub-chronic (60 days) test showed significant elevations in white blood cells, mid-sized Cells absolute, granulocytes absolute, lymphocytes percentage, granulocyte percentage, and platelets. Post-treatment cessation analysis showed notable differences in urea and low-density lipoprotein levels. Conclusion: These findings suggest that T. ivorensis possesses potent antibacterial properties against multidrug-resistant bacteria tested. Overall, the extract appears relatively safe at tested doses with mild immune activation.
Antibacterial activity, Terminalia ivorensis, Multidrug resistant, Phytochemistry, Toxicity
HOW TO CITE THIS ARTICLE
Ayoola GA, Adeluola AO, Abdullahi AS, Orojuekun DB, Johnson OO, Ologunagba M, et al. The antibacterial activities of Terminalia ivorensis A. Chev (Combretaceae) leaves against multidrug-resistant bacteria and its toxicity profile. J Phytopharmacol 2026; 15(1):1-12. doi: 10.31254/phyto.2026.15101
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