Antibacterial Activity of Kauranes from Annona squamosa L. Pericarp

Abstract

Bioactivity directed fractionation and isolation of active principles from the pericarp of Annona squamosa yielded three kauranes namely, (-)-ent-kaur-17-acetoxy, 19-oic acid, 16α, 17-dihydroxy-ent-kauran-19-oic acid and (-)-ent-kaur-17, 19-dioic acid. These compounds were tested against two bacteria, Staphylococus aureus (MTCC 737, S.N. Saxena, Staphlococcus Institute of Microbial Technology) and Escherichia. coli (MTCC 2991, N. Goel, Enterobacteriaceae, Institute of Microbial Technology). 16α, 17-Dihydroxy-ent-kauran-19-oic acid and (-)-entkaur- 17, 19-dioic acid at 100 μg and 500μg, respectively, showed more activity towards Escherichia. coli than the antibiotic, ampicillin at 500 μg and these kaurenes do not show promising activity towards Staphylococcus aureus, when compared with the standard drug, gentamycin. Here, we report the bioactivity directed fractionation, isolation and identification of the active principles by IR, NMR, MS and by the chemical conversions of the active compounds.