a1 Department of Food Biosciences, University of Reading, Whiteknights, Reading RG6 6AP, UK
The health benefits of green tea (Camellia sinensis) catechins are becoming increasingly recognised. Amongst the proposed benefits are the maintenance of endothelial function and vascular homeostasis and an associated reduction in atherogenesis and CVD risk. The mounting evidence for the influential effect of green tea catechins on vascular function from epidemiological, human intervention and animal studies is subject to review together with exploration of the potential mechanistic pathways involved. Epigallocatechin-3-gallate, one of the most abundant and widely studied catechin found in green tea, will be prominent in the present review. Since there is a substantial inconsistency in the published data with regards to the impact of green tea catechins on vascular function, evaluation and interpretation of the inter- and intra-study variability is included. In conclusion, a positive effect of green tea catechins on vascular function is becoming apparent. Further studies in animal and cell models using physiological concentrations of catechins and their metabolites are warranted in order to gain some insight into the physiology and molecular basis of the observed beneficial effects.
(Received November 27 2008)
(Revised April 17 2009)
(Accepted June 29 2009)
(Online publication September 15 2009)
Abbreviations: ACE, angiotensin-converting enzyme; ADMA, asymmetric dimethylarginine; Akt, protein kinase B; EC, epicatechin; ECG, epicatechin-3-gallate; EGC, epigallocatechin; EGCG, epigallocatechin-3-gallate; eNOS, endothelial NO synthase; FMD, flow-mediated dilatation; GTE, green tea extract; HUVEC, human umbilical vein endothelial cells; ICAM, intercellular adhesion molecule; l-NAME, Nω-nitro-l-arginine methyl ester; PGI2, prostacyclin; PI3K, phosphatidylinositol-3-kinase; UGT, UDP-glucuronosyltransferase; VCAM, vascular cell adhesion molecule