Effects of leucocyanidines on activities of metabolizing enzymes and antioxidant enzymes

Procyanidolic oligomers (lencocyanidines, LCs) extracted from grape seeds ( Vitis vinifera) are known to have antioxidant and antimutagenic activities, and a protective effect against cardiovascular disease. In the present stu dy were examined the influence of LCs on the activities of phase I enzymes and conjugation enzymes and on antioxidant enzymes such as superoxide dismu tase, catalase, and glutathione peroxidase. Administration of LCs (25, 50, and 100 mg/kg. p,o, for 7 d) markedly decreased the activities of NADPH-cyt ochrome P450 reductase, P4501A1, P4501A2, and P4503A4, but significantly in creased the activities of glutathione S-transferase and phenolsulfotransfel ase in rat liver However, the activities of antioxidant enzymes were not af fected by LC administration. The inhibition of P450s and increases in phase II enzyme activities indicate a role for LCs as a chemopreventive agent ag ainst toxic or carcinogenic metabolites of P450 isozymes.