Study May Explain Cardiac Benefit of Green Tea
A component of green tea reduces the production of a vasoconstrictor
THURSDAY, Jan. 7 (HealthDay News) -- A component of green tea reduces the production of a vasoconstrictor in endothelial cells, possibly explaining the beneficial cardiovascular effects of green tea, according to a study in the January issue of Endocrinology.
Chad E.N. Reiter and colleagues from the National Institutes of Health in Bethesda, Md., investigated whether epigallocatechin gallate (EGCG), a green tea polyphenol, controlled the expression of the vasoconstrictor endothelin-1 via the transcription factor FOXO1, partially explaining the ability of EGCG to promote vasodilation.
After treatment of human aortic endothelial cells with EGCG, the researchers found that EGCG reduced endothelin-1 production and secretion. FOXO1 regulated the endothelin-1 gene via binding to the endothelin-1 promoter, and further investigation showed that EGCG activated two proteins that partially regulated FOXO1 binding to the endothelin-1 promoter.
"The reduction of endothelin-1 expression by EGCG in endothelial cells may contribute to the reduced cardiovascular morbidity and mortality associated with drinking green tea," Reiter and colleagues conclude.