Contents of total polyphenols and total flavonoids in water extracts from leaf of Litsea coreana var. lanuginosa

(Migo) Yang et P. H. Huang were determined, and effects of these water extracts on scavenging sodium nitrite (NaNO₂ ) and blocking nitrosamine synthesis were studied. The results show that contents of total polyphenols and total flavonoids in water extracts from leaf of L. coreana var. lanuginosa are 4. 64% and 2. 96%, respectively. With enhancing of mass concentration of water extracts, both NaNO₂ scavenging rate and blocking rate of nitrosamine synthesis increase gradually,and there are obvious dose-effect relationships between mass concentration of water extracts with NaNO₂ scavenging rate and blocking rate of nitrosamine synthesis, their half-effect dose (ED50 ) are 0. 06 and 0. 25 mg·mL^-1, respectively. It is suggested that the effects of water extracts from leaf of L. coreana var. lanuginose on scavenging NaNO₂ and blocking nitrosamine synthesis are related to polyphenols and flavonoids in the water extracts.