Vol. 3, Special Issue 3, Part F (2017)

Abstract
The plant based drugs and chemical for curing various ailment used since old human civilization. Plants and plant based medicament are the basis of many of the modern pharmaceutical industries that we used today for our various ailments. The aim of the study was to find out the bioactive chemical constituents to study the antimicrobial activity of 95% methanol extract of bark of seven medicinal plants belongs to the different families. A qualitative phytochemical analysis was performed for the detection of alkaloids, glycosides, terpenoids, steroids, flavonoids, tannins and reducing sugar Preliminary evaluation of bark extract showed a broad spectrum of antimicrobial activity since the extract inhibit the growth of both gram positive and gram negative bacteria. The highest yield of methanolic extract was found in Azadiracta indica (34.39%). Dalbergia sisoo contained all the constituents except alkaloid. Polyalthia longifolia lacked alkaloid and terpenoid while Bauhinia variegata lacked steroid, tannin and reducing sugar. The extract of the crude extract of Aegle marmelos showed maximum inhibition for the species S. aureus and the crude extract of Bauhinia variegata showed maximum inhibition against Streptococcus pneumonia respectively. The crude extract of Dalbergia sisoo and Bauhinia variegata showed maximum inhibition against gram- negative bacteria E. coli and Klebsiella pneumonia respectively. Similarly, the extract of Azadiracta indica and Dalbergia sisoo were active against Staphylococcus aureus and Streptococcus pneumonia and the zone of inhibition of Polyalthia longifolia and Bauhinia variegata were active against E.coli and Klebsiella pneumonia respectively. This study therefore support the traditional uses of the plant in the treatment of infectious diseases.