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

Isolation and structure elucidation of three coumarins, murrayacoumarins A, B, and C, together with eight known coumarins, from the leaves of Murraya siamensis Craib collected in Thailand are described. Results of a primary screening of inhibitory effects of seven of these compounds on 12-O-tetradecanoylphorbol-13-acetate-induced Epstein-Barr virus early antigen activation in Raji cells are also presented.

Polyprenylated benzophenones from Garcinia assigu and their potential cancer chemopreventive activities.

In a further study on the chemical constituents of Garcinia assigu, two new benzophenones corresponding to the 13-O-methyl ethers (1 and 2) of the known isogarcinol and garcinol, respectively, were isolated and characterized, along with known benzophenones (3-6). Inhibitory effects of the benzophenones isolated from this plant on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells and their radical-scavenging ability against 1,1-diphenyl-2-picrylhydrazyl (DPPH) were demonstrated. The cyclized polyprenylbenzophenones (1-5) showed comparable or stronger potential cancer chemopreventive activity when compared to glycyrrhetic acid, a known anti-tumor promoter.