title: Green tea catechins and their metabolites in human skin before and after exposure to ultraviolet radiation.
abstract: Dietary flavonoids may protect against sunburn inflammation in skin. Preliminary reports using less complete analysis suggest that certain catechins and their metabolites are found in skin biopsies and blister fluid after consumption of green tea; however, it is not known if they are affected by solar-simulated ultraviolet radiation (UVR) or whether conjugated forms, with consequently altered bioactivity, are present. The present study tested the hypothesis that UVR affects the catechin levels in the skin of healthy volunteers after consumption of green tea and how catechins in the plasma are related to their presence in skin tissue samples. In an open oral intervention study, 11 subjects consumed green tea and vitamin C supplements daily for 3months. Presupplementation and postsupplementation plasma samples, suction blister fluid and skin biopsies were collected; the latter two samples were collected both before and after UVR. A sensitive high-performance liquid chromatography/mass spectrometric assay was used to measure the intact catechin metabolites, conjugates and free forms. Seven green tea catechins and their corresponding metabolites were identified postsupplementation in skin biopsies, 20 in blister fluid and 26 in plasma, with 15 green tea catechin metabolites present in both blister fluid and plasma. The valerolactone, O-methyl-M4-O-sulfate, a gut microbiota metabolite of catechins, was significantly increased 1.6-fold by UVR in blister fluid samples. In conclusion, there were some common catechin metabolites in the plasma and blister fluid, and the concentration was always higher in plasma. The results suggest that green tea catechins and metabolites are bioavailable in skin and provide a novel link between catechin metabolites derived from the skin and gut microbiota.
authors.affiliation: School of Food Science and Nutrition, University of Leeds, Leeds, United Kingdom.
authors.forename: Kayleigh A
authors.initials: KA
authors.lastname: Clarke
authors.affiliation: School of Food Science and Nutrition, University of Leeds, Leeds, United Kingdom.
authors.forename: Tristan P
authors.initials: TP
authors.lastname: Dew
authors.affiliation: Photobiology Unit, Centre for Dermatology Research, Institute of Inflammation and Repair, University of Manchester, Manchester Academic Health Science Centre, Salford Royal NHS Foundation Hospital, Manchester, United Kingdom.
authors.forename: Rachel E B
authors.initials: RE
authors.lastname: Watson
authors.affiliation: Photobiology Unit, Centre for Dermatology Research, Institute of Inflammation and Repair, University of Manchester, Manchester Academic Health Science Centre, Salford Royal NHS Foundation Hospital, Manchester, United Kingdom.
authors.forename: Mark D
authors.initials: MD
authors.lastname: Farrar
authors.affiliation: Photobiology Unit, Centre for Dermatology Research, Institute of Inflammation and Repair, University of Manchester, Manchester Academic Health Science Centre, Salford Royal NHS Foundation Hospital, Manchester, United Kingdom.
authors.forename: Joanne E
authors.initials: JE
authors.lastname: Osman
authors.affiliation: Manchester Pharmacy School, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, United Kingdom.
authors.forename: Anna
authors.initials: A
authors.lastname: Nicolaou
authors.affiliation: Photobiology Unit, Centre for Dermatology Research, Institute of Inflammation and Repair, University of Manchester, Manchester Academic Health Science Centre, Salford Royal NHS Foundation Hospital, Manchester, United Kingdom.
authors.forename: Lesley E
authors.initials: LE
authors.lastname: Rhodes
authors.affiliation: School of Food Science and Nutrition, University of Leeds, Leeds, United Kingdom. Electronic address: g.williamson@leeds.ac.uk.
authors.forename: Gary
authors.initials: G
authors.lastname: Williamson
mesh_terms: D000293:Adolescent; D000328:Adult; D001682:Biological Availability; D002392:Catechin / Q000097:blood / Q000493:pharmacokinetics / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006801:Humans; D057230:Limit of Detection; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D012867:Skin / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects*; D013662:Tea / Q000737:chemistry*; D014466:Ultraviolet Rays; D055815:Young Adult
chemical_list: D013662:Tea; D002392:Catechin
keywords: Bioavailability; Green tea catechin conjugates; Polyphenols; Skin; Ultraviolet radiation