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Abstract

Plants have served as a source of new pharmaceutical products and inexpensive starting materials for the synthesis of some known drugs. Components with medicinal properties from plants play an important role in conventional Western medicine. In the ethnopharmacological approach, local knowledge about the potential uses of the plants is very useful as compared to the random approach where indigenous knowledge is not taken into consideration. In the present study, the polar (hydro-alcoholic, aqueous, methanolic and ethanolic) extracts and non-polar extracts (hexane, chloroform and petroleum ether) of whole plant, Hyptis suaveolens was screened for antimicrobial activity against drug-resistant strains of Staphylococcus aureus and other pathogenic strains (viz. Pseudomonas aeruginosa, Bacillus cereus, Aspergillus niger and Candida albicans). All the polar extracts of the plant showed significant antimicrobial activity in comparison to non-polar extracts. The studies revealed that the polar extracts are having much significant antimicrobial activity against drug-resistant strains and other pathogenic strains while non-polar extracts are having moderate activity against pathogenic strains while no activity was found against drug-resistant strains. The polar extracts showed potent antibacterial activity against multidrug-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Aspergillus niger and Candida albicans in the ranges from 5.0 mg/ml to 15.0 mg/ml. The highest antimicrobial fractions of Hyptis suaveolens were chromatographed on 2 × 30 cm silica gel 60 open column using a stepwise gradient of methanol and increasing amount of ethyl acetate (20% at each step); ethyl acetate with increasing amount of methanol (10% at each step); and finally at 40% methanol. Collected fractions were evaporated under vacuum and examined by TLC. The antimicrobial fractions were examined using silica gel coated TLC plates to confirm the pure compound by changing the ratios of the solvent system components.