Sensitivity of Salmonella and Shigella to Mangifera indica Linn (Mango) Crude Leaf Extracts

Abstract

Aims: To study the antimicrobial activities of methanol, acetone and aqueous extracts of Mangifera indica Linn crude leaves on Salmonella and Shigella in order to provide natural therapy against them. Study Design: Salmonella and Shigella isolates were obtained from twenty-five stool samples of hospital patients. Six isolates were identified and characterized. The six isolates were labelled accordingly and used in the study. The antimicrobial activities of the extracts preliminary screened for the presence of phytochemical compounds were tested on the six isolates. Place and Duration of Study: The study was carried out in the Department of Microbiology, Delta State University, Abraka, Nigeria between October, 2012 and August, 2013.  Methodology: The test isolates (Salmonella and Shigella) were isolated from stool samples on Salmonella/Shigella agar and characterized. The phytochemical constituents of the leaves of M. indica were extracted by soaking in water, methanol and acetone. The extracts were investigated for antimicrobial activities on theisolates using the agar well diffusion method. Results: Phytochemical analysis of the leaf extract showed that the extracts contained alkaloids, tannins, flavonoids, steroids, anthroquinones, reducing sugars, glycosides and phenols. The acetone and methanol extracts exerted the highest zone of inhibition (18.00mm and 15.00mm respectively) though there was a significant difference (p<0.05) in the activities of the extracts. There was no significant difference (p>0.05) when compared with that of the water extract. Salmonella was more susceptible to acetone extract than Shigella with a Minimum Inhibitory Concentration of 25.00 mg/ml while that on Shigella was 50.00mg/ml. The MIC of the ethanolic extract on Salmonella was 50.00mg/ml while that of Shigella was 100.00mg/ml. Conclusion: The acetone and methanolextracts of the leaves of M. indica had high inhibitory effects on Salmonella and Shigella thus providing a basis for its recommendation in the treatment of diseases caused by these organisms.