Screening for antimicrobial activity of thirty-three medicinal plants used in the traditional system of medicine in Pakistan

Abstract

Ninety-nine aqueous, ethanolic and n-hexane extracts of thirty three medicinal plants from twenty six families used in the unani system of medicines in Pakistan were tested against ten commonly prevalent gram negative and gram positive bacteria’s particularly the enteric pathogens and yeast using agar diffusion disc method for their antimicrobial activity. Aqueous, ethanolic and n-hexane extracts of fifteen medicinal plants have no activity while other 18 plants have moderate to good antimicrobial activity. The aqueous and alcoholic extract of Adhatoda vasica Nees, Allium sativum Linn., Embelia ribes Burm. f. Mallotus phillippensis Muell., Picrorrhiza kurrooa Royle ex Benth., Ricinus communis Linn.,Elaeagnus hortensis M. Bieb., Swertia chirata Buch. Ham. and exhibited good activity against all or most of the microorganisms. The alcoholic extracts of Solanum nigrum Linn,Centella asiatica Linn, Solanum xanthocarpum Schrad and Wendl., Oxtostagia limbataBenth., Cassia angustifolia Vahl, Polygonum viviparum Linn. have moderate activity against some of the microbial strains. Antibacterial activity of some of the plant extracts can be compared with some antibiotics. This shows that Pakistan has a rich flora, having good potential of antimicrobial agents which can be used as a substitute of antibiotics and need for investigation of unexplored flora and screening for new antimicrobial agents. Key words: Antimicrobial properties, crude extracts, Pakistani medicinal plants.