New cinnamylphenols from Dalbergia species with cancer chemopreventive activity.

Five new cinnamylphenols (1,3-diphenylpropenes), dalberatins A (1), B (2), C (3), D (4), and E (5), were isolated from plants of the Dalbergia species. They were characterized and tested for their inhibitory activities against Epstein-Barr virus early antigen activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. The cinnamylphenols were found to show remarkably potent activities. The result of the present investigation indicated that some of these cinnamylphenols might be valuable as potential cancer chemopreventive agents (anti-tumor promoters).