Antibacterial and antifungal activities of different polar extracts from Anoectochilus roxburghii

This study evaluates the antibacterial and antifungal activities of petroleum ether, acetic ether, n-butanol and aqueous extracts from Anoectochilus roxburghii. The in vitro antibacterial and antifungal effects against three bacterial strains (Escherichia coli, Bacillus subtilis, Bacillus thuringiensis) and three fungal species (Exserohilum turcicum (Pass.) Leonard et Suggs, Botrytis cinerea Pers., Fusahum graminearum Sehw.) were assayed by the dilution and disc-diffusion methods. All of the polar extracts expressed dose-dependent antimicrobial activity against all tested microorganisms. The most active extract was aqueous extract, with a minimum inhibitory concentration below 0.625mg/ml in both bacteria and fungi. The results suggest that new chemical classes of natural antimicrobial substances (such as A. roxiburghii extracts) can be selectively exploited for the chemotherapy and control of infectious diseases.