Xylocarpins A-I, limonoids from the Chinese mangrove plant Xylocarpus granatum

Chemical examination of the fruits of the Chinese mangrove plant, Xylocarpus granatum, resulted in the isolation and characterization of nine new limonoids, named xylocarpins A-I (1-5, 7-10), along with nine known limonoids. Xylocarpins A-E were designated as polyoxyphragmalins, xylocarpin I was identified as a phragmalin orthoester, while xylocarpins F-H represented mexicanolides modified by ring oxidation and unusual 9,10-bond cleavage. The structure of xyloccensin U was revised to be 6-dehydroxyxylocarpin D on the basis of 2D spectroscopic data.