Absolute configurations of new limonoids from a Krishna mangrove, Xylocarpus granatum

Abstract

Four new limonoids, named granatumins V-Y (1-4), belonging to the small group of limonoids with a C1-C29 oxygen bridge and a ∆(8,30) double bond, were isolated from the seeds of an Indian mangrove, Xylocarpus granatum, collected in the swamp of Krishna estuary, Andhra Pradesh. The constitutions and absolute configurations of these compounds were established by extensive NMR investigations, single-crystal X-ray crystallography using Cu Kα radiation, and by the comparison of circular dichroism spectrum.

Keywords: Absolute configuration; Limonoids; Mangrove; Structure elucidation; Xylocarpus granatum.