A comparative study on phytochemical screening and antibacterial activity of roots of Alstonia scholaris with the roots, leaves and stem bark

Abstract

The present study was undertaken to investigate the antibacterial activity of roots, stem bark & leaves of various solvent (Hexane, Benzene, Isopropanol, Ethyl acetate, Methanol & Water) extracts of Alstonia scholaris using well diffusion techniques on Gram positive (Staphylococcus aureus, Bacillus cereus & Lactococcus lactis) as well as Gram negative bacteria (Aeromonas sp., Enterobacter aerogenes, Escherichia coli, Pseudomonas aeruginosa & Proteus mirabilis). Among the various extracts tested, methanol extract of root was found to be most potent against E.coli with a zone of inhibition of 18 mm followed by methanol extract of leaf against Lactococcus lactis (13.5 mm) and isopropanol extract of stem bark against Lactococcus lactis (13.3mm). Phytochemical analysis re- vealed the presence of alkaloids, carbohydrates, terpenoids, steroids & saponins in various extracts of roots, leaf  & stem bark.