| Author |
Mpho Granny Batlhophi, Freddy Bwacha, Barati Sandi Phirinyane, Olekile Tibe,
Emang Molojwane, Rosemary Ikalafeng Kobue-Lekalake, Ompelege Keolopile Matenanga,
Bonno Sekwati-Monang, Geremew Bultosa, Eyassu Seifu, Moenyane Molapisi,
John Gwamba, Kethabile Sonno, Gaone Mokhawa, et al |
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| Abstract |
Antimicrobial Resistance (AMR) poses a global health threat, necessitating exploration of natural alternatives such as plant-derived compounds. In Botswana, indigenous seed oils remain underutilised due to limited data on antimicrobial potential. This study aimed to evaluate the phytochemical composition and antibacterial activity of seed oils from four underutilised plants: Schinziophyton rautanenii (mongongo or manketti), Tylosema esculentum (morama), Bauhinia petersiana (mogose ), and Citrullus lanatus (Thunb.) Mansf (kgwengwe ).
Seeds were collected from three districts in Botswana, from which seed oils were prepared for antibacterial activity. Qualitative analysis for phytoconstituents was conducted through standard assay tests. Antibacterial activity against S . aureus ATCC 25923 and E. coli ATCC 25922 was assessed using the EUCASTguided
disk diffusion method, with tests performed in triplicate. Data were analysed using one-way ANOVA followed by Tukey’s HSD and Student’s ttests (p ≤ 0.05). Phytochemical analysis revealed the presence of terpenoids in
three oils, T. esulentum, S . rautanenii , and B. petersiana , with steroids in C. lanatus (Thunb.) Mansf. and saponins in S . rautanenii . All seed oils exhibited antibacterial activity against gram-negative S . aureus , with inhibition zones of 16.0 ± 0.00 (B. petersiana ), 9.33 ± 0.58 (T. esculentum), 7.00 ± 0.00 (S. rautanenii
), and 6.47 ± 0.06 (C. lanatus (Thunb.) Mansf.), showing significant differences (p < 0.001). C. lanatus (Thunb.) Mansf. yielded the lowest antibacterial activity. No activity was observed against gram-negative E. coli . Positive
controls (penicillin, gentamicin, tetracycline) confirmed the assay validity. These findings highlight the potential of these seed oils, particularly B. petersiana, as suitable plant-based antibacterial against gram-positive pathogens like S . aureus , a WHO high-priority AMR bacterium. Future studies should isolate active compounds, determine Minimum Inhibitory Concentration (MIC)/Minimum Bactericidal Concentration (MBC) values, evaluate efficacy against resistant strains and other foodborne pathogens, and explore optimised extraction methods to enhance yields and applications in food preservation and pharmaceuticals. |
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