Chemical Constituents of Calophyllum brasiliense. 2. Structure of Three New Coumarins and Cancer Chemopreventive Activity of 4-Substituted Coumarins

Continuing our search for cancer chemopreventive agents from natural sources, we examined constituents of the stem bark of Calophyllum brasiliense. Three new 4-substituted coumarins named brasimarins A (2), B (3), and C (4) were isolated and characterized, along with 11 known coumarins belonging to the calanolides or inophyllums. We also discuss the inhibitory effects of these coumarins on Epstein−Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells.