Antimicrobial activities and phytochemical profiles of endemic medicinal plants of Mauritius

Medicinal plants are assuming widespread use in the primary health care of individuals and communities. In the current study, we investigated the antimicrobial activities of two endemic plants, Antidesma madagascariense Lam. and Erythroxylum macrocarpum O. E. Schulz, which form part of the local pharmacopoeia of Mauritius. Aqueous and methanol extracts of the leaves and twigs of both plants were tested in vitro against three Gram-negative and five Gram- positive strains of bacteria, including a resistant strain of bacteria. Moreover, they were subjected to antifungal assays against Candida albicans ATCC 10231 and Aspergillus niger ATCC 16404, a human and a plant pathogenic microorganism, respectively, known to be good indicators of antifungal activity. It was found that aqueous extracts of both plants possess broad- spectrum antibacterial properties against the test organisms compared to methanol extracts, which gave poor inhibition zones. Moreover, the antibacterial substance within these plants seemed to be most prominent in the leaves and least in the twigs, and the best inhibitory activity was observed for Gram- positive bacteria ( Staphylococcus aureus ATCC 25923). Aqueous extracts of both plants do not possess antifungal properties except the methanol extract against A. niger. Phytochemical screening of the plants showed the presence of at least tannins, phenols, flavonoids, and alkaloids, which are known antimicorbial compounds. In conclusion, the observed antimicrobial properties would tend to further validate the medicinal properties of these commonly used endemic medicinal plants in Mauritius.