Chemoprotective potentials of homoisoflavonoids and chalcones of Dracaena cinnabari: Modulations of drug-metabolizing enzymes and antioxidant activity

A series of homoisoflavonoids and chalcones, isolated from the endemic trop ical plant Dracaena cinnabari Balf, (Agavaceae), were tested for their pote ntial to inhibit cytochrome P4501A (CYP1A) enzymes and Fe-enhanced in vitro peroxidation of microsomal lipids in C57B1/6 mouse liver. The effects of t he polyphenolic compounds were compared with those of prototypal flavonoid modulators of CYP1A and the well-known antioxidant, butylated hydroxytoluen e, 2-Hydroxychalcone and partly 4,6-diliydroxychalcone were found to be str ong inhibitors of CYP1A-dependent 7-ethoxyresorufin O-deethylase (EROD) act ivity in vitro comparable to the effects of quercetin and chrysin, The firs t screening of flavonoids and chalcones of Dracaena cinnabari for antioxida nt activity was done in an in vitro microsomal peroxidation assay. While ch alcones were shown to be poor antioxidants, 7,8-methylenedioxy-3 (4-hydroxy benzyl) chromane, as one of the tested homoisoflavonoids, exhibited a stron g antioxidant activity comparable to that of the strongest flavonol antioxi dant, quercetin. Copyright (C) 2001 John Wiley & Sons, Ltd.