Chemical constituents of Murraya siamensis: three coumarins and their anti-tumor promoting effect

Three coumarins, named murrayacoumarins A (1), B (2), and C, were isolated from the leaves of Murraya siamensis as inhibitors of Epstein-Barr virus early antigen activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells, along with eight known compounds. Their structures were elucidated on the basis of spectroscopic analyses.