title: Effect of 3-O-octanoyl-(+)-catechin on the responses of GABA(A) receptors and Na+/glucose cotransporters expressed in xenopus oocytes and on the oocyte membrane potential.
abstract: Recently, 3-O-octanoyl-(+)-catechin (OC) was synthesized from (+)-catechin (C) by incorporation of an octanoyl chain into C in the light of (-)-epicatechin gallate (ECg) and (-)-epigallocatechin gallate (EGCg), which are the major polyphenols found in green tea and have strong physiological activities. OC was found to inhibit the response of ionotropic gamma-aminobutyric acid (GABA) receptors (GABA(A) receptors) and Na+/glucose cotransporters expressed in Xenopus oocytes in a noncompetitive manner more strongly than does C. OC also induced a nonspecific membrane current and decreased the membrane potential of the oocyte, and thus death of the oocyte occurred even at lower concentrations than that induced by C or EGCg. Although EGCg produced H2O2 in aqueous solution, OC did not. This newly synthesized catechin derivative OC possibly binds to the lipid membrane more strongly than does C, Ecg, or EGCg and as a result perturbs the membrane structure.
authors.affiliation: Department of Physics, Biology and Informatics, Faculty of Science, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8512, Japan. aoshima@yamaguchi-u.ac.jp
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Aoshima
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Okita
authors.forename: Sheikh Julfikar
authors.initials: SJ
authors.lastname: Hossain
authors.forename: Keiko
authors.initials: K
authors.lastname: Fukue
authors.forename: Mariko
authors.initials: M
authors.lastname: Mito
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Orihara
authors.forename: Terufumi
authors.initials: T
authors.lastname: Yokoyama
authors.forename: Mamoru
authors.initials: M
authors.lastname: Yamada
authors.forename: Ayako
authors.initials: A
authors.lastname: Kumagai
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Nagaoka
authors.forename: Shinichi
authors.initials: S
authors.lastname: Uesato
authors.forename: Yukihiko
authors.initials: Y
authors.lastname: Hara
mesh_terms: D000818:Animals; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D002417:Cattle; D015870:Gene Expression; D006861:Hydrogen Peroxide / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects*; D009004:Monosaccharide Transport Proteins / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D009865:Oocytes / Q000378:metabolism* / Q000648:ultrastructure*; D011963:Receptors, GABA-A / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D011994:Recombinant Proteins; D014982:Xenopus laevis
chemical_list: C499927:3-O-octanoyl-catechin; D009004:Monosaccharide Transport Proteins; D011963:Receptors, GABA-A; D011994:Recombinant Proteins; D002392:Catechin; D006861:Hydrogen Peroxide