Effects of green tea on gene expression of hepatic gluconeogenic enzymes in vivo.

It has recently been reported that the major green tea polyphenolic constituent, epigallocatechin 3-gallate (EGCG), mimics the cellular effects of insulin including the reductive effect on the gene expression of rate-limiting gluconeogenic enzymes in a cell culture system. We show that administration of green tea that contains EGCG caused a reduction in the level of mRNAs for gluconeogenic enzymes, phosphoenolpyruvate carboxykinase and glucose-6-phosphatase in the mouse liver. EGCG alone was also found to down-regulate the gene expression of these enzymes but not so curcumin or quercetin. The results of this study support the idea that green tea intake may be beneficial in the prevention of diabetes mellitus.