ANTIMICROBIAL ACTIVITY OF FEW SELECTED MEDICINAL PLANTS

Abstract

The petroleum ether, chloroform, methanol and aqueous extracts of leaves of Ageratum conyzoides Linn (Fam: Asteraceae), Argemone mexicana Linn. (Fam: Papaveraceae), Heliotropium indicum Linn (Fam: Boraginaceae) and stem barks of Alstonia scholaris (L.) R. Brown (Fam: Apocynaceae) were screened for their antimicrobial activity against Bacillus subtilis, Stapphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger respectively. The results indicated that the chloroform, methanol and aqueous extracts of all tested plant materials are active against both Gram- positive and Gram-negative bacteria at the tested concentration. The spectrum of activity observed in the present study may be an indicative of the presence of broad spectrum antimicroial compounds in the extracts. Among the tested extracts, methanol extracts of all selected plant materials were found to be more effective than the other extracts under study. Preliminary phytochmical screening of the methanol extracts of selected plant materials primarily revealed presence of alkaloids, tannins and flavonoids. The present work justifies the use of these plant materials for antimicrobial activity as claimed in the folklore remedies.