Antibacterial Activities of Some Medicinal Plants on Common Multidrug-Resistant Bacterial Isolates from Some Patients Attending Federal Medical Center, Birnin Kebbi, Nigeria

Abstract

Bacterial infections are among the major causes of morbidity and mortality worldwide. The development of drug resistance to most antibiotics by bacterial species are pandemic, these necessitate the urgent need to search for new antibacterial drugs from the natural sources. Hence this research was aimed at evaluating the antibacterial activity of some medicinal plants on the most commonly drug resistant bacterial isolates from some patients attending Federal Medical Center (FMC) Birnin Kebbi, Nigeria. An ethno-botanical survey was carried out within Zuru Emirate and three (3) plant samples (Lonchocarpus laxiflorus root, Mitragyna inermis root and Lawsonia inermis root) were selected based on their number of citations and limited number of reported researches on the antibacterial activities of their roots. The multidrug resistant bacterial strains (Staplococcus aureus, Escherichia coli and Psuedomonas aeruginosa) obtained from FMC, Birnin Kebbi, were taken from nutrient agar slant and sub-cultured in nutrient agar plates. The antibacterial activities of the root methanol extracts of the plants were evaluated using agar-well diffusion method. Tube dilution method was used to determine the minimum inhibitory concentration of each plant extract. The preliminary phytochemical screening of the extracts was conducted using standard methods. Alkaloids, Flavaniods, Steriods, Tannins, saponnins and Phenols, were detected in L. laxiflorus root methanol extract, Flavaniods were absent in L. inermis and Alkaloids in M. inermis root methanol extracts. The plant extracts and their combinations showed varying degrees of antibacterial activities on the test isolates. The root methanol extracts of L. laxiflorus, L. inermis, L. laxiflorus/L. inermis, L. laxiflorus/M. inermis and L. inermis/M. inermis roots presented significant increase (p<0.05) in the zone of inhibition against S. aureus. Extracts of L. laxiflorus root, L. inermis root and combination of M. inermis root were able to suppress the growth of P. aeruginosa at lower dose of 25mg/ml. The antibacterial activity revealed that, the extracts exhibited dose dependent effect. L. inermis root had the highest activity and least MIC value of 12.5mg/ml against all the tested isolates. Thus, this research justified the use of these plants in traditional medicine for the treatment of bacterial infections and can also be considered as potential sources for development of new antibacterial agents that may be more effective, safe and readily accessible than the current antibiotics.