Two new 4-arylcoumarins from the seeds of Calophyllum polyanthum

Two new 4-arylcoumarins, 7,4'-dihydroxy-6,8-dimethoxy-4-phenylcoumarin (1) and 7-hydroxy-6,8,4'-trimethoxy-4-phenylcoumarin (2), together with four known compounds were isolated from the seeds of Calophyllum polyanthum. The structures of the new compounds were determined by extensive spectroscopic analyses, and the structure of compound 2 was confirmed by X-ray crystallography analysis. Both new compounds exhibited significant cell protective activities against H(2)O(2)-induced human umbilical vein endothelial cell damage.