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.
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.
Aoshima
Hitoshi
H
Department of Physics, Biology and Informatics, Faculty of Science, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8512, Japan. aoshima@yamaguchi-u.ac.jp
Okita
Yoichi
Y
Hossain
Sheikh Julfikar
SJ
Fukue
Keiko
K
Mito
Mariko
M
Orihara
Yusuke
Y
Yokoyama
Terufumi
T
Yamada
Mamoru
M
Kumagai
Ayako
A
Nagaoka
Yasuo
Y
Uesato
Shinichi
S
Hara
Yukihiko
Y
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
C499927:3-O-octanoyl-catechin; D009004:Monosaccharide Transport Proteins; D011963:Receptors, GABA-A; D011994:Recombinant Proteins; D002392:Catechin; D006861:Hydrogen Peroxide