Improvement of Endothelial Function by EGCG

The Role of EGCG in Different Application Forms on Flow-mediated Dilation in Healthy Volunteers

Status

Completed

Phases

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT01662232

Enrollment

Registered

2012-08-10

Start date

2012-08-31

Completion date

2013-09-30

Last updated

2016-02-03

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Cardiovascular Diseases

Keywords

Green tea, EGCG, Cardiovascular diseases, Endothelial function, Flow-mediated dilation

Brief summary

Cardiovascular diseases are a major cause of morbidity and mortality worldwide. Impaired endothelial function (assessed as flow-mediated dilation) represents an early marker for later cardiovascular events. Epidemiological and experimental studies suggest that consumption of tea is associated with lower progression of atherosclerosis and reduced cardiovascular mortality. Tea contains high amounts of polyphenols with important biological activities. The green tea catechin epigallocatechin-3-gallate (EGCG) is the most potent physiologically active compound in vitro. However, little is known about its contribution to beneficial effects of tea in vivo. In this crossover study the impact of a single dose of EGCG applied in different forms (green tea beverage, green tea extract and EGCG) on flow-mediated dilation is investigated in healthy volunteers two hours after ingestion. The amount of EGCG (200 mg) corresponds to appr. 0.5 L of green tea. The results of the study will elucidate the contribution of EGCG in cardiovascular protective effects of green tea in vivo. The outcomes will provide insights about the role of EGCG in different application forms to improvements of endothelial function in humans.

Interventions

DIETARY_SUPPLEMENTGreen tea beverage

DIETARY_SUPPLEMENTGreen tea extract

DIETARY_SUPPLEMENTEGCG

OTHERPlacebo

Study design

Allocation

RANDOMIZED

Intervention model

CROSSOVER

Primary purpose

PREVENTION

Masking

NONE

Eligibility

Sex/Gender

MALE

Age

20 Years to 50 Years

Healthy volunteers

Yes

Inclusion criteria

* Male healthy volunteers * 20-50 years * BMI \< 27 kg/m2 * Cholesterol \< 240 mg/dl

Exclusion criteria

* Diabetes mellitus * Hypertension * Conditions with impaired endothelial function * Smoking * Regular drug use * Alcohol abuse * Regular tea drinkers

Design outcomes

Primary

Measure	Time frame	Description
Flow-mediated dilation of the arteria brachialis	2 hours after ingestion	Change in flow-mediated dilation (in %) of the arteria brachialis after a single dose of 200 mg EGCG either as green tea beverage, green tea extract or EGCG is assessed by vascular ultrasound.

Secondary

Measure	Time frame	Description
Agonist-induced platelet aggregation in vitro	2 hours after ingestion	Blood is drawn two hours after consumption and the effects on in vitro agonist-induced platelet aggregation after a single dose of 200 mg EGCG either as green tea beverage, green tea extract or EGCG are measured.
Determination of plasma tea polyphenol levels	2 hours after ingestion	Blood is drawn two hours after consumption and plasma concentrations of tea polyphenols are measured after a single dose of 200 mg EGCG either as green tea beverage, green tea extract or EGCG by HPLC.

Countries

Germany

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026