Issah A.O¹, Azeez I.A², Boyejo A.O^1,, Owolabi S.L³, Buhari O.A⁴, Ikeola M.F⁵

Despite the wide availability of clinically useful antibiotics and semi-synthetic analogues, a continuing search for new anti-infective agents remains indispensable, therefore this study was carried out to determine the antibacterial activities of some medicinal plants against bacterial isolates. The seeds, leaves and stem bark of some plants with medicinal claims were purchased from Itoku market, Abeokuta. The plant parts were grinded using an electric miller. The crude extract of the plants were prepared by cold maceration and were tested for antimicrobial activity using agar diffusion method. Those plants with activities were further extracted with N-hexane, Chloroform, Ethyl acetate, Butanol, Ethanol, Methanol and Water using continuous cold extraction technique with aid of separating funnel. Susceptibility testing of the extract obtained was performed using agar well diffusion and broth macro dilution techniques. Bactericidal effect and mode of action of the extracts were performed using Minimum Bactericidal Concentration (MBC) and time kill test technique. Phytochemistry was performed according to standard chemical techniques. Out of the twelve different medicinal plants screened, Terminalia avicenniodes and Magnifera indica possess antibacterial potentials. Methanol extract of Terminalia avicenniodes bark had the highest percentage yield of 17.8% while the ethanol extract of Magnifera indica leaves has the least percentage yield of 3.6 %. Susceptibility test revealed that the ethanol extract of the Magnifera indica leave against Escherichia coli ATCC 29929 has the widest Diameter Zone of Inhibition (DZI) (23.333±2.887), while the methanol extract of Magnifera indica leaves have no antibacterial effect on Klebsiella pneumoniae ATCC 4252. The methanol extract of the leaves of Magnifera indica against Escherichia coli ATCC 29929 and the methanol extract of the leaves of Terminalia avicennoides against Klebsiella pneumoniae ATCC 4252 and Shigella dysentariae have the highest MIC (12.500±0.000) while the ethanol extract of the leave and methanol extract of the leaves and stem bark of Terminalia avicennoides against Staphylococcus aureus ATCC 29293(3.125±0.000) has the lowest MIC. There was no significant difference in the MBC of all the extracts. The stem bark and leaves of the plants contains tannin, phytosterol, phenol, diterpenes, proteins and amino acid, reducing sugar and non reducing carbohydrate. The time kill test revealed that the methanol extract of the Magnifera indica leaves and the ethanol extract of Terminalia avicenniodes killed Escherichia coli ATCC 29929 within 60 mins, while most of the plant extracts killed klebsiella pneumoniae within 20hrs. In conclusion, Terminalia avicennoides and Magnifera indica have strong inhibitory activity against the bacteria isolates, and can be studied further for the Chemotherapeutic drug production.

Terminalia avicennoides, Magnifera indica, Antibacterial, Phytochemistry