Antibacterial activity of aqueous extract of Calotropis gigantea leaves - An in vitro study

Abstract

Calotropis gigantea is a common wasteland weed and known for various medicinal properties. The aim of the present study was to screen leaves of Calotropis gigantea for the antimicrobial activity against clinical isolates of bacteria. The aqueous extract of the C. gigantea was studied for its antagonistic activity against Staphylococcus aureus, Escherichia coli, Bacillus cereus, Pseudomonas aeruginosa, Micrococcus luteus and Klebsiella pneumoniae. In vitro antimicrobial activity was performed by well diffusion method in MH agar. The extract showed significant effect on the tested organisms. The extract showed maximum zone of inhibition against E. coli (17.6±1.15), whereas, lowest against K. pneumoniae (12.6±1.52). Crude extract showed maximum relative percentage inhibition against B. cereus (188.52 %) and lowest relative percentage inhibition against M. luteus (24.92 %). Minimum Inhibitory Concentration (MIC) was measured by modified agar well diffusion method. Extract showed 50, 25, 6.25, 3.1, 1.5 and 12.5 mg/ml MIC values for S. aureus, K. pneumoniae, B. subtilis, P. aeruginosa, M. luteus and E. coli, respectively.