title: Heat-epimerized tea catechins rich in gallocatechin gallate and catechin gallate are more effective to inhibit cholesterol absorption than tea catechins rich in epigallocatechin gallate and epicatechin gallate.
abstract: It has been known that tea catechins, (-)-epicatechin (1), (-)-epigallocatechin (2), (-)-epicatechin gallate (3), and (-)-epigallocatechin gallate (4) are epimerized to(-)-catechin (5), (-)-gallocatechin (6), (-)-catechin gallate (7), and (-)-gallocatechin gallate (8), respectively, during retort pasteurization. We previously reported that tea catechins, mainly composed of 3 and 4, effectively inhibit cholesterol absorption in rats. In this study, the effect of heat-epimerized catechins on cholesterol absorption was compared with tea catechins. Both tea catechins and heat-epimerized catechins lowered lymphatic recovery of cholesterol in rats cannulated in the thoracic duct and epimerized catechins were more effective than tea catechins. The effect of purified catechins on micellar solubility of cholesterol was examined in an in vitro study. The addition of gallate esters of catechins reduced micellar solubility of cholesterol by precipitating cholesterol from bile salt micelles. Compounds 7 and 8 were more effective to precipitate cholesterol than 3 and 4, respectively. These observations strongly suggest that heat-epimerized catechins may be more hypocholesterolemic than tea catechins.
authors.affiliation: Laboratory of Nutrition Chemistry, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School of Kyushu University, Fukuoka 812-8581, Japan. iikeda@kyushu-u.ac.jp
authors.forename: Ikuo
authors.initials: I
authors.lastname: Ikeda
authors.forename: Makoto
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Tadateru
authors.initials: T
authors.lastname: Hamada
authors.forename: Koichi
authors.initials: K
authors.lastname: Tsuda
authors.forename: Hitomi
authors.initials: H
authors.lastname: Goto
authors.forename: Katsumi
authors.initials: K
authors.lastname: Imaizumi
authors.forename: Ayumu
authors.initials: A
authors.lastname: Nozawa
authors.forename: Akio
authors.initials: A
authors.lastname: Sugimoto
authors.forename: Takami
authors.initials: T
authors.lastname: Kakuda
mesh_terms: D000818:Animals; D002392:Catechin / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry* / Q000494:pharmacology*; D002784:Cholesterol / Q000737:chemistry / Q000493:pharmacokinetics*; D006358:Hot Temperature; D007408:Intestinal Absorption / Q000187:drug effects*; D008297:Male; D008823:Micelles; D051381:Rats; D017207:Rats, Sprague-Dawley; D012995:Solubility; D013662:Tea / Q000737:chemistry*
chemical_list: D008823:Micelles; D013662:Tea; C417940:gallocatechin gallate; C417939:catechin gallate; D002392:Catechin; C062669:epicatechin gallate; D002784:Cholesterol; C045651:epigallocatechin gallate