Effects of black tea consumption on plasma catechins and markers of oxidative stress and inflammation in patients with coronary artery disease.

Abstract

We previously demonstrated that black tea consumption reverses endothelial dysfunction in patients with coronary artery disease. To investigate potential mechanisms of this effect, we examined plasma catechins and systemic markers of oxidation, inflammation, and antioxidant protection from 66 subjects enrolled in that study. We collected samples at baseline, 2 h after 450 ml of black tea (acute), after 4 weeks of 900 ml of black tea per day (chronic), and after acute and chronic consumption of water. Total catechins increased 33% after acute tea (P < 0.05) and 29% after chronic tea (P < 0.05). Of individual catechins, plasma epicatechin gallate (ECG) concentration significantly increased with acute tea consumption, and plasma epicatechin (EC) increased with chronic tea consumption. Tea consumption did not improve plasma antioxidant capacity and did not reduce urinary 8-hydroxy-2'-deoxyguanosine, or urinary 8-isoprostane levels. Changes in catechin levels did not correlate with changes in endothelial function, plasma markers of oxidative stress, or C-reactive protein. In contrast, endothelial function at baseline correlated with dietary flavonoid intake (beta = 0.32, P = 0.02) and with baseline plasma EC concentration after adjusting for confounding variables (beta = 0.39, P = 0.03). These findings suggest that the benefits of black tea consumption on endothelial function may not be attributable to tea catechins or a systemic antioxidant or anti-inflammatory effect. Chronic dietary flavonoid status appears to relate to endothelial function, possibly suggesting that other flavonoids or polyphenolic components of tea favorably influence vascular health and risk for cardiovascular disease.

• Authors: Michael E Widlansky, Stephen J Duffy, Naomi M Hamburg, Noyan Gokce, Beverly A Warden, Sheila Wiseman, John F Keaney Jr, Balz Frei, Joseph A Vita
• Journal: Free radical biology & medicine (Free Radic Biol Med) Vol. 38 Issue 4 Pg. 499-506 (Feb 15 2005) ISSN: 0891-5849 [Print] United States
• PMID: 15649652 (Publication Type: Clinical Trial, Controlled Clinical Trial, Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Plant Extracts
• Tea
• Catechin

Topics

• Catechin (blood)
• Coronary Artery Disease (blood, diet therapy)
• Endothelial Cells (drug effects, metabolism)
• Female
• Humans
• Inflammation (blood, diet therapy)
• Male
• Middle Aged
• Oxidation-Reduction
• Oxidative Stress (drug effects, physiology)
• Phytotherapy
• Plant Extracts (pharmacology, therapeutic use)
• Tea (chemistry)