Validation of green tea polyphenol biomarkers in a phase II human intervention trial.
Food Chem Toxicol
; 46(1): 232-40, 2008 Jan.
Article
em En
| MEDLINE
| ID: mdl-17888558
ABSTRACT
Health benefits of green tea polyphenols (GTPs) have been reported in many animal models, but human studies are inconclusive. This is partly due to a lack of biomarkers representing green tea consumption. In this study, GTP components and metabolites were analyzed in plasma and urine samples collected from a phase II intervention trial carried out in 124 healthy adults who received 500- or 1000-mg GTPs or placebo for 3 months. A significant dose-dependent elevation was found for (-)-epicatechin-3-gallate (ECG) (p<0.001, trend test) and (-)-epigallocatechin-3-gallate (EGCG) (p<0.05, trend test) concentrations in plasma at both 1-month and 3-months after intervention with GTPs. No significant increase of (-)-epicatechin (EC) or (-)-epigallocatechin (EGC) was observed in plasma after GTP intervention. A mixed-effects model indicated significant effects of dose (EGCG) and dose by time interaction (ECG), but not for EC and EGC. Analysis of phase 2 metabolic conjugates revealed a predominance of free GTPs in plasma, up to 85% for EGCG, while a majority of GTPs in urine were sulfated and glucuronidated conjugates (up to 100% for EC and 89% for EGC). These results suggest that plasma ECG and EGCG concentrations are reliable biomarkers for green tea consumption at the population level.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Fenóis
/
Chá
/
Flavonoides
/
Biomarcadores
Tipo de estudo:
Clinical_trials
/
Prognostic_studies
Idioma:
En
Revista:
Food Chem Toxicol
Ano de publicação:
2008
Tipo de documento:
Article
País de afiliação:
Estados Unidos