Emeka John Dingwoke¹ , Fatima Adis Adamude², Ikenna Ezeaku³, Kingsley Onyekachi Moh⁴, Judith Chinelo Amailo¹, Maryann Chidimma Enemmuo¹, Chukwuemeka Paul Nweje-Anyalowu^{5, 6}, Raymond Ogbonna Offiah⁷, Chijioke Cyril Ilechukwu⁸, Bruno Ikenna Aguh⁹, Abdulhadi Abubakar¹⁰, Adaora Chinemelum Onodugo¹¹, Onyemuche Tochukwu Nnamdi¹²

¹UNESCO International Center for Biotechnology, Nsukka 410001, Enugu State; ¹⁰Department of Medical Microbiology, Ahmadu Bello University Teaching Hospital, Zaria, Kaduna State; ¹¹Department of Biochemistry, Federal University, Oye-Ekiti, Ekiti State; ¹²Department of Biochemistry, Faculty of Biological Sciences, Alex Ekwueme Federal University, Ndufu-Alike, Ebonyi State, Nigeria. ²Department of Biochemistry, Faculty of Life Science, Federal University of Lafia, Nasarawa State, Nigeria; ³Department of Surgical Recovery and Perfusion, Gift of Hope, Itasca IL, USA; ⁴Department of Biotechnology, Mewar International University, Masaka, Nasarawa State; ⁵Department of Chemical Sciences, Faculty of Science, Clifford University, Owerrinta, Abia State; ⁶Department of Biochemistry, Faculty of Biological Sciences, University of Nigeria, Nsukka, Enugu State; ⁷Department of Pharmacology and Therapeutics, Faculty of Clinical Medicine, College of Medicine, Enugu State University of Science and Technology, Enugu, Enugu State; ⁸Department of Biochemistry, Faculty of Natural Sciences, Chukwuemeka Odumegwu Ojukwu University, Uli, Anambra State; ⁹Department of Biological Sciences, Faculty of Science, Federal University Gusua, Zamfara State;

For correspondence:-  Emeka Dingwoke   Email: emeka.jd@unescoicb.org.ng

Received: 4 March 2025        Accepted: 12 June 2025        Published: 03 July 2025

Citation: Dingwoke EJ, Adamude FA, Ezeaku I, Moh KO, Amailo JC, Enemmuo MC, et al. Terminalia avicennioides root bark extract: A promising phytotherapeutic agent against methicillin-resistant Staphylococcus aureus hospital strains. Trop J Pharm Res 2025; 24(6):779-786 doi: https://dx.doi.org/10.4314/tjpr.v24i6.4

© 2025 The authors.
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Abstract

Purpose: To investigate the antibacterial activity of a partially purified ethyl acetate fraction obtained from methanol
extract of the root bark of Terminalia avicennioides (Family: Combretaceae) against a hospital strain of methicillinresistant
Staphylococcus aureus (MRSA).
Methods: Gas chromatography-mass spectrometry (GC-MS) was used to identify and characterize compounds in
the bioactive fraction of T. avicennioides root bark, while Fourier Transform Infrared (FTIR) spectroscopy was used to
elucidate the functional groups. The MRSA hospital strain was isolated from a clinical sample and the isolate
biochemically characterized by colonial morphology, Gram staining, and strain reaction. Resistance to
methicillin/oxacillin was confirmed by repeat susceptibility testing using oxacillin. The antibacterial efficacy of the
fraction was compared with those of standard antibiotics including meropenem, amoxiclav, nitrofurantoin, ceftriaxone,
nidof, and ciprofloxacin. Antimicrobial activity was evaluated using agar well diffusion method, while the minimum
inhibitory concentration (MIC) was determined using a 10-fold serial broth dilution assay.
Results: Mass spectrometry analysis revealed that the ethyl acetate fraction with anti-MRSA activity comprised a
mixture of seven compounds in varying proportions, viz: n-hexadecanoic acid, 11-octadecenoic acid, oleic acid,
octadecanoic acid, 3,11-tetradecadien-1-ol, 9-octadecenal, and (9Z)-9-tetradecenal. The FTIR spectra indicated the
presence of alkyl halides. At 100 μg/mL, the ethyl acetate fraction exhibited a bacteriostatic effect, with a minimum
bactericidal concentration (MBC) of 9.48 ± 0.90 μg/mL. Based on Kirby-Bauer standard, it demonstrated bactericidal
activity (MBC) at 150 μg/mL, with mean inhibition zone diameter of 14 mm.
Conclusion: The synergistic action of the seven identified compounds in the bioactive fraction may offer a promising
foundation for developing novel drug candidates with potent bactericidal activity against hospital-acquired MRSA
strains.

Keywords: Terminalia avicennioides, Methicillin-resistant Staphylococcus aureus, Bioactive fraction, Antibacterial activity

Impact Factor
Thompson Reuters (ISI): 0.6 (2023)
H-5 index (Google Scholar): 49 (2023)