title: Preventive effect of epicatechin and ginsenoside Rb(2) on the inhibition of gap junctional intercellular communication by TPA and H(2)O(2).
abstract: The anticarcinogenic effects of epicatechin (EC) and ginsenoside Rb(2) (Rb(2)), which are major components of green tea and Korea ginseng, respectively, were investigated using a model system of gap junctional intercellular communication (GJIC) in WB-F344 rat liver epithelial cells. 12-O-tetradecanoylphorbol-13-acetate (TPA) and hydrogen peroxide, known as cancer promoters, inhibited GJIC in the epithelial cells as determined by the scrape loading/dye transfer assay, fluorescence redistribution assay after photobleaching, and immunofluorescent staining of connexin 43 using a laser confocal microscope. The inhibition of GJIC by TPA and H(2)O(2) was prevented with treatment of Rb(2) or EC. The effect of EC on GJIC was stronger in TPA-treated cells than in H(2)O(2)-treated cells, while the effect of Rb(2) was opposite to that of EC. EC, at the concentration of 27.8 microg/ml, prevented the TPA-induced GJIC inhibition by about 60%. Rb(2,) at the concentration of 277 microg/ml, recovered the H(2)O(2)-induced GJIC inhibition by about 60%. These results suggest that Rb(2) and EC may prevent human cancers by preventing the down-regulation of GJIC during the cancer promotion phase and that the anticancer effect of green tea and Korea ginseng may come from the major respective components, EC and Rb(2).
authors.affiliation: Department of Veterinary Public Health, College of Veterinary Medicine, Seoul National University, 103 Seodun-Dong, Kwonsun-Ku, Suwon, South Korea.
authors.forename: K S
authors.initials: KS
authors.lastname: Kang
authors.forename: B C
authors.initials: BC
authors.lastname: Kang
authors.forename: B J
authors.initials: BJ
authors.lastname: Lee
authors.forename: J H
authors.initials: JH
authors.lastname: Che
authors.forename: G X
authors.initials: GX
authors.lastname: Li
authors.forename: J E
authors.initials: JE
authors.lastname: Trosko
authors.forename: Y S
authors.initials: YS
authors.lastname: Lee
mesh_terms: D000818:Animals; D002392:Catechin / Q000494:pharmacology*; D002450:Cell Communication / Q000187:drug effects*; D002478:Cells, Cultured; D018031:Connexin 43 / Q000032:analysis; D004847:Epithelial Cells; D017629:Gap Junctions / Q000187:drug effects*; D036145:Ginsenosides; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D008099:Liver; D010766:Phosphorylation; D051381:Rats; D012503:Saponins / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
chemical_list: D018031:Connexin 43; D036145:Ginsenosides; D012503:Saponins; C048026:ginsenoside Rb2; D002392:Catechin; D006861:Hydrogen Peroxide; D013755:Tetradecanoylphorbol Acetate