Presence of Aldose Reductase Inhibitors in Tea Leaves

The Japanese Journal of Pharmacology

Shinji Okuwaki¹  Takashi Suzuki²  Takayo Murano¹  Itaru Sakai²  Tsunehisa Makino¹  Shun-ichiro Izumi¹ 

[1] Department of Obstetrics and Gynecology, Tokai University School of Medicine;Bio-Team, Applied Technology Research Center, NKK Corporation

关键词: Aldose reductase;    Enzyme inhibitor;    Tea leaf;    Human placenta;    Diabetes;   

DOI  :  10.1254/jjp.85.322

学科分类：药理学

来源: Nihon Yakuri Gakkai Henshuubu / Japanese Pharmacological Society

【 摘 要 】

References(25)Cited-By(9)Water extract from commercial English tea has a potent inhibitory activity against human placenta aldose reductase (NADPH oxidoreductase, E.C.1.1.1.21.). Inhibitory activity was separated into five major fractions by one-step chromatography with a C-18 reverse phase column. The most active fraction was further subjected to reverse phase column chromatography. As a result, a well-known flavone-glycoside, isoquercitrin, was isolated as the most potent chemical. The inhibitory character of isoquercitrin for aldose reductase was a mix of uncompetitive and noncompetitive inhibitions, and its IC50 was 1 × 10−6 M. In rat sciatic nerve tissue preparations, sorbitol accumulation in the presence of high concentrations of glucose (30 mM) was inhibited by 38% at 5 × 10−4 M of isoquercitrin. The flavone-glycoside isoquercitrin is the active inhibitor of aldose reductase inhibitor present in English tea. Given the ability of aldose reductase inhibitors to prevent diabetic complications, an epidemiological study of the effect of tea consumption on the pathogenesis and progression of diabetic complications would be interesting.

【 授权许可】

Unknown