Three New Benzophenone-Xanthone Dimers from the Root of Garcinia dulcis

Investigation of the chemical constituents of the roots of Garcinia dulcis resulted in the isolation of three new benzophenone-xanthone dimers named garciduols A-C (1-3) in addition to a new xanthone, 1, 3, 6-trihydroxy-7-methoxyxanthone (4). Five known xanthones [2, 5-dihydroxy-1-methoxy- (5), 1, 4, 5-trihydroxy- (6), 1, 3, 5-trihydroxy- (7), 1, 3, 6-trihydroxy-5-methoxy- (8) and 1, 3, 6-trihydroxy-8-isoprenyl-7-methoxyxanthone (9)] were also isolated from the roots. Their structures were determined by spectroscopic analysis including two dimensional NMR. The behaviors of chemical shifts caused by acetylation and the position of the methoxyl group in the dimers characterized by model synthetic benzophenones are also discussed.