A new ent-kaurane from the root extract of Chiococcaalba

Abstract

A bioassay-guided purification of the methanolic crude extract obtained from the roots of Chiococcaalba (L.) Hitchc. resulted in the isolation of a new, bioactive, metabolite identified as ent-17-hydroxy-16α-kauran-3-one (1). Elucidation of the new structure was based on analyses of the results obtained from various spectroscopic methods (IR, MS, 1H NMR, and 13C NMR) and chemical transformations. The stereochemistry at C16 was assigned by comparing both the proton and carbon chemical shifts of C17 with those reported in the literature. The new kaurane showed weak antimicrobial activity when tested against Staphylococcusaureus. Keywords: medicinal plants, Chiococcaalba, Rubiaceae, kaurane, diterpene, antimicrobial.