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

Four new limonoids, named granatumins V-Y (1-4), belonging to the small group of limonoids with a C-1-C-29 oxygen bridge and a Delta(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 K alpha radiation, and by the comparison of circular dichroism spectrum. (C) 2014 Elsevier B.V. All rights reserved.