Evaluation of the Antimicrobial Activity of Different Solvent Extracts of Ipomoea littoralis (Blume): A Naturally Growing Medicinal Plant in Sri Lanka

Aims: The emergence of drug-resistant microbial pathogens has become a global health burden. Hence there is a timely need to discover novel anti-microbial agents. The aim of the current study was evaluate the anti-microbial potential of different extracts of Ipomoea littoralis against some pathogens causing gastro-intestinal tract infections.

Study Design: Experimental study.

Place and Duration of Study: Department of Basic Sciences at Faculty of Allied Health Sciences and Research Laboratory at Faculty of Medicine, General Sir John Kotelawala Defence University, Ratmalana, Sri Lanka, between July 2018 and November 2018.

Methodology: The aqueous, methanol, acetone and hexane extracts were prepared with the leaves, roots and stem of the plant Ipomoea littoralis separately. The agar well diffusion method and broth dilution method were applied in order to screen the anti -microbial activity of each test extract against the Escherichia coli, Salmonella enterica, Shigella dysenteriae, Candida albicans and Staphylococcus aureus. Statistical comparisons were made using Duncan's new multiple range test. Significance was set at P = .05.

Results: The zone of inhibition of most of the test extracts showed a significant (P = .05) difference when compared with the negative control, suggesting that majority of the extracts of the selected plant material are active against the tested pathogens. The observed lowest MIC value was 31.25 mg/ml, while the highest MIC value was 250 mg/ml. Aqueous and acetone extracts of stem showed the lowest MIC value against E. coil, while methanol and acetone leaves extracts showed highest inhibition against S. enterica. The MIC value was 31.25 mg/ml against S. aureus by aqueous stem, hexane leaves and methanol stem extracts. The aqueous stem, hexane roots and the acetone leaves extract showed the lowest (31.25 mg/ml) MIC value against C. albicans. The MIC value was 31.25 mg/ml for methanol leaves and stem extract against S. dysenteriae.

Conclusion: The anti- microbial potency of different solvent extracts of the plant I. littoralis is varied against different pathogens causing gastro-intestinal tract infections.