![]() |
|
|


* Division of Human Nutrition and Epidemiology, Wageningen University, Wageningen, The Netherlands;
RIKILT, Wageningen, The Netherlands; and
** Unilever Health Institute, Unilever Research Vlaardingen, The Netherlands
2To whom correspondence should be addressed. E-mail: margreet.olthof{at}wur.nl.
Dietary phenols are antioxidants, and their consumption might contribute to the prevention of cardiovascular disease. Coffee and tea are major dietary sources of phenols. Dietary phenols are metabolized extensively in the body. Lack of quantitative data on their metabolites hinders a proper evaluation of the potential biological effects of dietary phenols in vivo. The aim of this study was to identify and quantify the phenolic acid metabolites of chlorogenic acid (major phenol in coffee), quercetin-3-rutinoside (major flavonol in tea) and black tea phenols in humans, and determine the site of metabolism. Healthy humans (n = 20) with an intact colon participated in a dietary controlled crossover study, and we identified and quantified
60 potential phenolic acid metabolites in urine. Half of the ingested chlorogenic acid and 43% of the tea phenols were metabolized to hippuric acid. Quercetin-3-rutinoside was metabolized mainly to phenylacetic acids, i.e., 3-hydroxyphenylacetic acid (36%), 3-methoxy-4-hydroxyphenylacetic acid (8%) and 3,4-dihydroxyphenylacetic acid (5%). In contrast, in seven humans without a colon, we found only traces of phenolic acid metabolites in urine after they had ingested chlorogenic acid and quercetin-3-rutinoside. This implies that the colonic microflora convert most of these dietary phenols into metabolites that then reach the circulation. Metabolites of dietary phenols have lower antioxidant activity than their parent compounds; therefore, the contribution of dietary phenols to antioxidant activity in vivo might be lower than expected from in vitro tests.
KEY WORDS: chlorogenic acid quercetin black tea metabolism humans
This article has been cited by other articles:
![]() |
G. M. Woodward The potential effect of excessive coffee consumption on nicotine metabolism: CYP2A6 inhibition by caffeic acid and quercetin Bioscience Horizons, May 2, 2008; (2008) hzn021v1. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Monteiro, A. Farah, D. Perrone, L. C. Trugo, and C. Donangelo Chlorogenic Acid Compounds from Coffee Are Differentially Absorbed and Metabolized in Humans J. Nutr., October 1, 2007; 137(10): 2196 - 2201. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. L. Prior, L. Gu, X. Wu, R. A. Jacob, G. Sotoudeh, A. A. Kader, and R. A. Cook Plasma Antioxidant Capacity Changes Following a Meal as a Measure of the Ability of a Food to Alter In Vivo Antioxidant Status J. Am. Coll. Nutr., April 1, 2007; 26(2): 170 - 181. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Lafay, A. Gil-Izquierdo, C. Manach, C. Morand, C. Besson, and A. Scalbert Chlorogenic Acid Is Absorbed in Its Intact Form in the Stomach of Rats J. Nutr., May 1, 2006; 136(5): 1192 - 1197. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. A. Graf, C. Ameho, G. G. Dolnikowski, P. E. Milbury, C.-Y. Chen, and J. B. Blumberg Rat Gastrointestinal Tissues Metabolize Quercetin J. Nutr., January 1, 2006; 136(1): 39 - 44. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. Yang, Z. Meng, J. Dong, L. Yan, L. Zou, Z. Tang, and G. Dou METABOLIC PROFILE OF 1,5-DICAFFEOYLQUINIC ACID IN RATS, AN IN VIVO AND IN VITRO STUDY Drug Metab. Dispos., July 1, 2005; 33(7): 930 - 936. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Manach, G. Williamson, C. Morand, A. Scalbert, and C. Remesy Bioavailability and bioefficacy of polyphenols in humans. I. Review of 97 bioavailability studies Am. J. Clinical Nutrition, January 1, 2005; 81(1): 230S - 242S. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. P Mulder, A. G Rietveld, and J. M van Amelsvoort Consumption of both black tea and green tea results in an increase in the excretion of hippuric acid into urine Am. J. Clinical Nutrition, January 1, 2005; 81(1): 256S - 260S. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. Halliwell, J. Rafter, and A. Jenner Health promotion by flavonoids, tocopherols, tocotrienols, and other phenols: direct or indirect effects? Antioxidant or not? Am. J. Clinical Nutrition, January 1, 2005; 81(1): 268S - 276S. [Abstract] [Full Text] [PDF] |
||||
![]() |
I. C. Arts and P. C. Hollman Polyphenols and disease risk in epidemiologic studies Am. J. Clinical Nutrition, January 1, 2005; 81(1): 317S - 325S. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Gouedard, R. Barouki, and Y. Morel Dietary Polyphenols Increase Paraoxonase 1 Gene Expression by an Aryl Hydrocarbon Receptor-Dependent Mechanism Mol. Cell. Biol., June 15, 2004; 24(12): 5209 - 5222. [Abstract] [Full Text] [PDF] |
||||