Abstract: OBJECTIVE: To investigate the elimination effect of tea polyphenols on exogenous nitrite both in vitro and vivo. METHODS: To measure the elimination rate of tea polyphenols on exogenous nitrite within simulated gastric juice in vitro(37 ℃,pH=3). A total of 18 SD rats were randomly divided into 3 groups after administrating intragastrically with 40 mg/kg nitrite: group A(treated with 100 mg/kg tea polyphenols by gavage immediately),group B(treated with 100 mg/kg tea polyphenols by gavage 15 min later),group C(treated with distilled water by gavage 15 min later,blank control).Then the concentrations of nitrite in rat plasma at different times were determined by Griess colorimetric method. RESULTS: After TP was mixed with nitrite for 10 minutes in vitro, the nitrite clearance rate was up to 94.4％. The elimination rates showed no statistical significance as time prolonged(P>0.05). The concentrations of plasma nitrite in group C increased after 15 min and reached its peak of (0.793 ±0.110) mg/L 45 min later,then decreased to the minimum of (0.646±0.088) mg/L 60 min later.The concentrations of plasma nitrite in group A reached a peak of (0.599±0.154) mg/L 15 min later, reduced gradually to a minimum of (0.461±0.098) mg/L 45 min later, then remained stable. Rats in group B developed peak plasma nitrite of (0.653±0.220) mg/L 45 min later, fell to a minimum of (0.484±0.198) mg/L 60 min later,then remained stable. At 30 min, the concentration of plasma nitrite of group A was significantly lower than group B and C(P<0.05）. CONCLUSION: Tea polyphenols could eliminate exogenous nitrite both in vitro and vivo.The elimination of immediate treatment with tea polyphenols by gavage was significantly more effective than the treatment 15 min later. Early treatment with TP could effectively eliminate the nitrite in stomach. After exogenous nitrite was absorbed into the blood, the eliminating effect of TP was limited.

Key words: tea polyphenols, exogenous nitrite, eliminating effect