title: Systemic Absorption of Catechins after Intraruminal or Intraduodenal Application of a Green Tea Extract in Cows.
abstract: Green tea catechins have various potential health benefits in humans including anti-inflammatory, anti-oxidative and hepato-protective effects. If present in the circulation, they might have similar effects in ruminants, which are exposed to oxidative stress and fatty liver disease such as dairy cows during the periparturient phase. However, the bioavailability of a substance is a prerequisite for any post absorptive effect in vivo. This study aimed to investigate the appearance of catechins from a green tea extract (GTE) in cattle plasma after intraruminal and intraduodenal administration because absorption is of major importance regarding the bioavailability of catechins. The studies were performed in 5 rumen-fistulated non-lactating heifers and 6 duodenally fistulated lactating dairy cows, respectively, equipped with indwelling catheters placed in a jugular vein. The GTE was applied intraruminally (10 and 50 mg/kg BW, heifers) or duodenally (10, 20 and 30 mg/kg BW, dairy cows) in a cross-over design with a 2 d washout period between different dosages. Blood samples were drawn following the GTE administration at various pre-defined time intervals. The concentration of the major GTE catechins (gallocatechin, epigallocatechin, catechin, epicatechin, epigallocatechin-gallate, epicatechin-gallate) in plasma samples were analysed by HPLC with electrochemical detection. Irrespective of the dose, almost none of the catechins originally contained in the GTE were detected in plasma samples after intraruminal application. In contrast, intraduodenal administration of GTE resulted in increased plasma concentrations of epicatechin, epigallocatechin, epigallocatechin gallate in a dose-dependent manner. Thus, we can conclude that intraruminally or orally administered catechins are intensively metabolized by ruminal microorganisms.
authors.affiliation: Institute of Animal Nutrition & Physiology, Christian-Albrechts-University of Kiel, Kiel, Germany.
authors.forename: Silvia
authors.initials: S
authors.lastname: Wein
authors.affiliation: Institute of Animal Nutrition & Physiology, Christian-Albrechts-University of Kiel, Kiel, Germany.
authors.forename: Birgit
authors.initials: B
authors.lastname: Beyer
authors.affiliation: Institute of Nutritional Physiology, Leibniz Institute for Farm Animal Biology, Dummerstorf, Germany.
authors.forename: Annika
authors.initials: A
authors.lastname: Gohlke
authors.affiliation: Institute of Animal Nutrition & Physiology, Christian-Albrechts-University of Kiel, Kiel, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Blank
authors.affiliation: Institute of Nutritional Physiology, Leibniz Institute for Farm Animal Biology, Dummerstorf, Germany.
authors.forename: Cornelia C
authors.initials: CC
authors.lastname: Metges
authors.affiliation: Institute of Animal Nutrition & Physiology, Christian-Albrechts-University of Kiel, Kiel, Germany.
authors.forename: Siegfried
authors.initials: S
authors.lastname: Wolffram
mesh_terms: D000818:Animals; D001682:Biological Availability; D002392:Catechin / Q000031:analogs & derivatives* / Q000493:pharmacokinetics*; D002408:Catheters, Indwelling; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D016154:Digestive System Fistula; D004386:Duodenum / Q000378:metabolism; D005260:Female; D065569:Gastrointestinal Absorption / Q000502:physiology; D007601:Jugular Veins; D010936:Plant Extracts / Q000737:chemistry / Q000493:pharmacokinetics; D012417:Rumen / Q000378:metabolism; D013662:Tea / Q000737:chemistry*
chemical_list: D010936:Plant Extracts; D013662:Tea; D002392:Catechin; C062669:epicatechin gallate; C045651:epigallocatechin gallate; C057580:gallocatechol