Do flavan-3-ols from green tea reach the human brain?

Abstract Following acute ingestion of green tea by six human subjects, HPLC-MS 2 analysis revealed that flavan-3-ol methyl, glucuronide and sulfate metabolites appeared in the bloodstream but did not pass through the blood–cerebrospinal fluid barrier. These observations emphasize the discrepancies between in vitro and in vivo evidence on the neuroprotective role of these compounds. If, as has been proposed, green tea exerts neuroprotective effects, this finding indicates that the active components are not flavan-3-ols or their metabolites. Alternatively, a systemic action may be hypothesised whereby dietary flavan-3-ols up-regulate antioxidant defences and/or reduce inflammation, the benefit of which may be effective throughout the body.

[1]  F. Mattivi,et al.  Fast access of some grape pigments to the brain. , 2005, Journal of agricultural and food chemistry.

[2]  C. Auger,et al.  The absorption, metabolism and excretion of flavan-3-ols and procyanidins following the ingestion of a grape seed extract by rats , 2005, British Journal of Nutrition.

[3]  C. Felgines,et al.  Anthocyanin metabolism in rats and their distribution to digestive area, kidney, and brain. , 2005, Journal of agricultural and food chemistry.

[4]  B. Shukitt-Hale,et al.  Anthocyanins in aged blueberry-fed rats are found centrally and may enhance memory , 2005, Nutritional neuroscience.

[5]  B. Shukitt-Hale,et al.  Flavonoids and the brain: interactions at the blood-brain barrier and their physiological effects on the central nervous system. , 2004, Free radical biology & medicine.

[6]  Danny D Shen,et al.  Principles and applicability of CSF sampling for the assessment of CNS drug delivery and pharmacodynamics. , 2004, Advanced drug delivery reviews.

[7]  Hyoung-Gon Lee,et al.  Modulation of Hippocampal Plasticity and Cognitive Behavior by Short-term Blueberry Supplementation in Aged Rats , 2004, Nutritional neuroscience.

[8]  S. Mandel,et al.  Neurological mechanisms of green tea polyphenols in Alzheimer's and Parkinson's diseases. , 2004, The Journal of nutritional biochemistry.

[9]  S. Mandel,et al.  Catechin polyphenols: neurodegeneration and neuroprotection in neurodegenerative diseases. , 2004, Free radical biology & medicine.

[10]  J. Andersen,et al.  Oxidative stress in neurodegeneration: cause or consequence? , 2004, Nature Reviews Neuroscience.

[11]  N. Oku,et al.  Suppressive effect of green tea catechins on morphologic and functional regression of the brain in aged mice with accelerated senescence (SAMP10) , 2004, Experimental Gerontology.

[12]  G. Williamson,et al.  How should we assess the effects of exposure to dietary polyphenols in vitro? , 2004, The American journal of clinical nutrition.

[13]  M. Nedergaard,et al.  The blood–brain barrier: an overview Structure, regulation, and clinical implications , 2004, Neurobiology of Disease.

[14]  D. Begley,et al.  Corrigendum to Flavonoid permeability across an in situ model of the blood–brain barrier. Free Radic. Biol. Med. 36: 592–604; 2004. , 2004 .

[15]  M. Lean,et al.  HPLC-MSn analysis of phenolic compounds and purine alkaloids in green and black tea. , 2004, Journal of agricultural and food chemistry.

[16]  Daniel Offen,et al.  The role of oxidative stress in the pathogenesis of multiple sclerosis: The need for effective antioxidant therapy , 2004, Journal of Neurology.

[17]  D. Begley,et al.  Flavonoid permeability across an in situ model of the blood-brain barrier. , 2004, Free radical biology & medicine.

[18]  M. Oechsner,et al.  Plasma and CSF markers of oxidative stress are increased in Parkinson's disease and influenced by antiparkinsonian medication , 2004, Neurobiology of Disease.

[19]  C. Rice-Evans,et al.  Interaction between flavonoids and the blood–brain barrier: in vitro studies , 2003, Journal of neurochemistry.

[20]  C. Rice-Evans,et al.  Uptake and metabolism of epicatechin and its access to the brain after oral ingestion. , 2002, Free radical biology & medicine.

[21]  D. Barron,et al.  Human metabolism of dietary flavonoids: Identification of plasma metabolites of quercetin , 2001, Free radical research.

[22]  K. Nakagawa,et al.  Dose-dependent incorporation of tea catechins, (-)-epigallocatechin-3-gallate and (-)-epigallocatechin, into human plasma. , 1997, Bioscience, biotechnology, and biochemistry.

[23]  H. Li,et al.  Analysis of plasma and urinary tea polyphenols in human subjects. , 1995, Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology.

[24]  Gary Williamson,et al.  Bioavailability and bioefficacy of polyphenols in humans. II. Review of 93 intervention studies. , 2005, The American journal of clinical nutrition.

[25]  Gary Williamson,et al.  Bioavailability and bioefficacy of polyphenols in humans. I. Review of 97 bioavailability studies. , 2005, The American journal of clinical nutrition.

[26]  A. Crozier,et al.  On-line high-performance liquid chromatography analysis of the antioxidant activity of phenolic compounds in green and black tea. , 2005, Molecular nutrition & food research.