Quinonoids from the barks of Cratoxylum formosum subsp.pruniflorum

A mixture of new bianthrones J (1a and 1b) was isolated from the barks of Cratoxylum formosum subsp. pruniflorum together with six known quinonoids, namely bianthrone A1 (2), vismones E (3) and D (4), 11-hydroxy-5-methoxy-2,2,9-trimethyl-2H-anthra[1,2-b]-pyran-7,12-dione (5), vismiaquinone (6), and 3-geranyloxy-6-methyl-1,8-dihydroxyanthraquinone (7). Their structures were assigned on the basis of spectroscopic methods. The antibacterial and cytotoxic activities of compounds 3 and 4 were also reported.Key words: Cratoxylum formosum subsp. pruniflorum, bianthrone, vismone, anthraquinone, antibacterial activity, cytotoxicity.