Abstract

Six different organic solvents such as ethanol, methanol, petroleum ether, hexane, benzene and chloroform were used to extract the bioactive compounds from the rhizome of Drynaria quercifolia to screen the antibacterial activity against infectious disease causing bacterial pathogens such as Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella typhi, Salmonella paratyphi A, Salmonella paratyphi B, Serratia marscence, Staphylococcus aureus and Bacillus subtilis by agar diffusion method. The ethanolic extract of D. quercifolia was more active against 80% of the organisms tested. It was followed by methanolic extract (70%), benzene (50%) and chloroform extract (40%) in inhibiting the growth of the organisms tested. Petroleum ether and hexane extract of D. quercifolia did not show any antibacterial activity against any of the pathogenic bacteria tested. Among the bacteria tested, gram-negative bacteria were more susceptible to the crude extracts compared to gram-positive bacteria. Among gram-positive bacteria, S. aureus was susceptible to ethanolic, methanolic and chloroform extracts whereas B. subtilis was susceptible to methanolic extract of D.  quercifolia alone. In the present study ethanolic and methanolic extracts of rhizome of D. quercifolia showed high efficiency of antibacterial activity and gram-negative bacteria were more susceptible to all the extracts tested.

Key words: Drynaria quercifolia, rhizome, crude extract, antibacterial activity.