Two new compounds from the roots of Swietenia macrophylla .

Phytochemical investigation on the roots of Swietenia macrophylla yielded one new pharagmalin-type limonoid named 2-dehydroxyl-swietephragmin C ( 1 ) and one new xanthone, 1,5-dihydroxy-6-methoxy-6',6'-dimethyl-2 H -pyrano[2',3':3,2]xanthone ( 2 ), in addition to three known compounds. The structures of the new compounds were unambiguously determined by comprehensive spectroscopic methods (NMR, UV, IR, MS), as well as by comparison with the reported data in the literature. Xanthones were reported from Swietenia genus for the first time.