title: Effects of co-administration of tea epigallocatechin-3-gallate (EGCG) and caffeine on absorption and metabolism of EGCG in humans.
abstract: Based on the ratios of (-)-epigallocatechin-3-gallate (EGCG) and caffeine (CAF) levels found in commercial tea drinks, EGCG and CAF were co-administered to human volunteers at various EGCG/CAF ratios, and plasma EGCG was determined by high performance liquid chromatography with chemiluminescence detection. As for the results, in plasma taken after ingestion of a beverage containing 95 mg of EGCG alone, the area under the plasma EGCG concentration-time curve (AUC) was 857 ngxh/ml. A higher AUC (1,370 ngxh/ml) was observed when subjects ingested a beverage containing EGCG (95 mg) and a low amount of CAF (40 mg). In the case of ingestion of a beverage containing EGCG (95 mg) and a high amount of CAF (180 mg), the AUC tended to be somewhat higher (1,165 ngxh/ml), but not significantly so, compared with the beverage with EGCG alone. These findings (modulation of plasma EGCG level by CAF) provide ideas for modulating the bioavailability of tea catechins, which can be applied to tea-related drinks and foods.
authors.affiliation: Food and Biodynamic Chemistry Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan. nkgw@biochem.tohoku.ac.jp
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Nakagawa
authors.forename: Kayoko
authors.initials: K
authors.lastname: Nakayama
authors.forename: Miho
authors.initials: M
authors.lastname: Nakamura
authors.forename: Phumon
authors.initials: P
authors.lastname: Sookwong
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Tsuduki
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Niino
authors.forename: Fumiko
authors.initials: F
authors.lastname: Kimura
authors.forename: Teruo
authors.initials: T
authors.lastname: Miyazawa
mesh_terms: D000328:Adult; D002110:Caffeine / Q000008:administration & dosage* / Q000097:blood; D002392:Catechin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D049449:Luminescence; D013056:Spectrophotometry, Ultraviolet; D013662:Tea / Q000737:chemistry*
chemical_list: D013662:Tea; D002110:Caffeine; D002392:Catechin; C045651:epigallocatechin gallate