Antibacterial, antifungal and insecticidal activities of the n-hexane and ethyl-acetate fractions of methanolic extract of the leaves of Calotropis gigantea Linn

The study was conducted to evaluate the therapeutic potentials and insecticidal effects of Calotropis gigantea leaves against pathogenic bacteria, fungi, and insect by disc diffusion method. Five different species of Gram-positive and Gram-negative bacteria, six species of fungi, and Tribolium castaneum (Herbst) insect were used. No antibacterial and antifungal activities were observed for n-hexane fraction of the methanolic extract of Calotropis gigantea leaves but the ethyl-acetate fraction showed potential inhibitory effects on all tested bacteria and fungi except Trichophyton rubrum. The ethyl-acetate fraction showed significant inhibition of Escherichia coli, Shigella flexneri and Shigella sonnei. The best antifungal activity was recorded for the ethyl-acetate fraction against Candida albicans. In insecticidal activity assay, the ethyl-acetate fraction showed better activity with 80% mortality rate at a dose of 50 mg/ml in 48 hours whereas n-hexane fraction showed 40% mortality rate. Both fractions were almost nontoxic to tested insect up to 12 hours. The results established a good support for the use of Calotropis gigantea leaves in traditional medicine and insecticide.