tailieunhanh - Báo cáo khoa học: "Transactivation of peroxisome proliferator-activated receptor alpha by green tea extracts"

Tuyển tập các báo cáo nghiên cứu khoa học quốc tế về bệnh thú y đề tài: Transactivation of peroxisome proliferator-activated receptor alpha by green tea extracts | J. Vet. Sci. 2004 5 4 325-330 JOURNAL OF Veterinary Science Transactivation of peroxisome proliferator-activated receptor a by green tea extracts Kookkyung Lee Department of Veterinary Medicine Cheju National University Jeju 690-756 Korea Tea is a popular beverage. Recently green tea was reported to increase the number of peroxisomes in rats. In this study to find out whether the green tea-induced proliferation of peroxisomes is mediated by PPARa a transient transfection assay was carried out to investigate the interactions of tea extracts green tea black tea oolong tea and doongule tea and tea components epigallocatechin gallate epigallocatechin epicatechin gallate epicatechin and gallic acid with mouse cloned PPARa. Green tea and black tea extracts and epigallocatechin gallate a major component of fresh green tea leaves increased the activation of PPARa times compared with the control. It is suggested that the green tea induced-peroxisomal proliferation may be mediated through the transactivation of PPARa and that epigallocatechin gallate may be an effective component of green tea leaves. This would account for the increase in the number of peroxisomes and the activity of peroxisomal enzymes previously reported. However black tea a fully fermented product had a stronger effect than oolong tea extract. These results also suggest that in addition to epigallocatechin gallate green tea leaves may possess some active chemicals newly produced as a result of the fermentation process which act on PPARa like other peroxisome proliferators. Key words Peroxisome proliferator-activated receptor green tea epigallocatechin gallate Introduction Tea is a preparation made from dried leaves of Camellias sinensis being one of the most widely consumed and popular beverages in the world. Tea was discovered in China where it has been consumed due to its medical properties since BC 3000 5 . The significance of the daily Corresponding author Tel 82-64-754-3378 82-11-9709-3248 Fax