Screening of Methanol and Acetone Extracts of Fourteen Indian Medicinal Plants for Antimicrobial Activity

The methanol and acetone extracts of 14 plants belonging to different families were evaluated for antimicrobial activity against five Gram-positive bacteria: Staphylococcus aureus, Staphylococcus epidermidis, Bacillus cereus, Bacillus subtilis, Micrococcusflavus; seven Gram-negative bacteria: Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Proteusvulgaris, Salmonella typhimurium, Citrobacter freundii; and three fungi: Candida tropicalis, Cryptococcus luteolus and Candidaalbicans. The in vitro antimicrobial activity was performed by agar disc diffusion method. The extractive yield was more in methanol than in acetone. The methanol extracts showed more antibacterial activity than acetone extracts. The most susceptible bacterium was K. pneumoniae and the most resistant were P. vulgaris, S. typhimurium, P. aeruginosa and E. coli. Preliminary phytochemical analysis revealed the presence of tannins, cardiac glycosides, steroids and saponins. Among the plant species screened, the best antimicrobial activity was shown by Aristolochia indica; hence, this plant can be further subjected to isolation of the therapeutic antimicrobials and to further pharmacological evaluation.