Antimicrobial properties of the extracts of locally sold garlic and neem leaf in Benin City, Nigeria

Different varieties of medicinal plants have been reported and a recent study on various herbal plants sold in Benin City, Nigeria has revealed the presence of disease causing organisms present on them. This report questions the antimicrobial potency of these locally sold varieties of medicinal plants. In this study, we obtained garlic and neem leaf from local herbal practitioners in Benin City, Nigeria and prepared three different extracts (methanol, acetone and chloroform) of both samples. We then used the disc diffusion method of antimicrobial assay to analyse the antimicrobial properties of these extracts against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Salmonella typhi. Our results showed that at least two of the test organisms are susceptible to each garlic extract, with the chloroform extract having the most antimicrobial property against all microorganisms at concentration as low as 2.26mg/ml. The extracts of neem leaf however showed antimicrobial property against S. aureus and E. coli only with the acetone extract having the highest antimicrobial potency against these two organisms at a concentration of 6.84mg/ml. These results thus revealed the antimicrobial property of locally sold garlic and neem leaf for herbal medicines. However, it is suggested that these plants be thoroughly washed with water before use to reduce or eliminate any microbial contamination due to field contamination.