Acute EGCG supplementation reverses endothelial dysfunction in patients with coronary artery disease.
BACKGROUND
Epidemiological studies demonstrate an inverse relation between dietary flavonoid intake and cardiovascular risk. Recent studies with flavonoid-containing beverages suggest that the benefits of these nutrients may relate, in part, to improved endothelial function.


OBJECTIVE
We hypothesized that dietary supplementation with epigallocatechin gallate (EGCG), a major catechin in tea, would improve endothelial function in humans.


METHODS
We examined the effects of EGCG on endothelial function in a double blind, placebo-controlled, crossover design study. We measured brachial artery flow-mediated dilation by vascular ultrasound at six time points: prior to treatment with EGCG or placebo, two hours after an initial dose of EGCG (300 mg) or placebo, and after two weeks of treatment with EGCG (150 mg twice daily) or placebo. The order of treatments (EGCG or placebo) was randomized and there was a one-week washout period between treatments.


RESULTS
A total of 42 subjects completed the study, and brachial artery flow-mediated dilation improved from 7.1 +/- 4.1 to 8.6 +/- 4.7% two hours after the first dose of 300 mg of EGCG (P = 0.01), but was similar to baseline (7.8 +/- 4.2%, P = 0.12) after two weeks of treatment with the final measurements made approximately 14 hours after the last dose. Placebo treatment had no significant effect, and there were no changes in reactive hyperemia or the response to sublingual nitroglycerin. The changes in vascular function paralleled plasma EGCG concentrations, which increased from 2.6 +/- 10.9 to 92.8 +/- 78.7 ng/ml after acute EGCG (P < 0.001), but were unchanged from baseline after two weeks of treatment (3.4 +/- 13.1 ng/ml).


CONCLUSIONS
EGCG acutely improves endothelial function in humans with coronary artery disease, and may account for a portion of the beneficial effects of flavonoid-rich food on endothelial function.
Widlansky
Michael E
ME
Evans Department of Medicine, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA.
Hamburg
Naomi M
NM
Anter
Elad
E
Holbrook
Monika
M
Kahn
David F
DF
Elliott
James G
JG
Keaney
John F
JF
Vita
Joseph A
JA
D000284:Administration, Oral; D000975:Antioxidants; D001628:Beverages; D001783:Blood Flow Velocity / Q000187:drug effects*; D001916:Brachial Artery / Q000187:drug effects / Q000503:physiopathology; D002392:Catechin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000494:pharmacology; D003324:Coronary Artery Disease / Q000188:drug therapy* / Q000503:physiopathology; D018592:Cross-Over Studies; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013662:Tea / Q000737:chemistry; D014664:Vasodilation / Q000187:drug effects* / Q000502:physiology
D000975:Antioxidants; D013662:Tea; D002392:Catechin; C045651:epigallocatechin gallate