Cytotoxic xanthones from Cudrania tricuspidata

The new isoprenylated tetrahydroxyxanthone, 2,3,6,8-tetrahydroxy-1-(3-methylbut-2-enyl)-5-(2-methylbut3-en-2-yl)-9H-xanthen-9-one (1), was isolated from the root bark of Cudrania tricuspidata together with macluraxanthone B (2) and cudraxanthone L (3), which were fully characterized by NMR spectroscopic and X-ray crystallographic analyses.