Enteral infusion of green tea extract selectively enhances the biliary secretion of 14C-benzo[a]pyrene in rats without affecting other biliary lipids.

摘要

Studies have suggested that green tea extract (GTE) decreases intestinal absorption of benzo[a]pyrene (BAP), an extremely lipophilic food contaminant. Effects of an enteral infusion of GTE on biliary secretion of BAP and lipids in rats were determined. Females were fed AIN-93G with or without (control) GTE at 5 g/kg diet for 4 wk. Following the 4-wk treatment, rats with bile duct cannula were infused continuously for 8 h at 3.0 ml/h via a duodenal catheter and lipid emulsion containing 4.0 mumol BAP labelled with 14C (14C-BAP), 20.7 mumol cholesterol, 452 mumol triolein and 3.1 mumol alpha-tocopherol, and 396.0 mumol Na-taurocholate with or without 76.1 mg GTE powder in PBS buffer (pH, 6.4). Bile was collected hourly via bile cannula for 8 h. Results showed that bile flow did not differ between groups. However, biliary secretion of 14C-BAP was enhanced by GTE infusion compared to rats infused with the lipid emulsion alone. GTE did not affect biliary outputs of cholesterol, fat, phospholipid and alpha-tocopherol. Results suggest GTE has a strong stimulatory effect on biliary excretion of BAP in rats without affecting other biliary lipids.