Protection of active oxygen-related neuronal injuries by tea catechins

• Published in: Japanese Journal of Pharmacology Vol. 71; no. suppl.1; p. 102
• Main Authors: Annaka, Toshimitsu, Kobori, Yoshiko, Matsuoka, Yutaka, Sunagane, Nobuyoshi, Uruno, Tsutomu, Kubota, Kazuhiko
• Format: Journal Article
• Language: English; Japanese
• Published: The Japanese Pharmacological Society 1996
• ISSN: 0021-5198
• DOI: 10.1016/S0021-5198(19)36646-6

The activities of tea catechins, (+)-catechin (CA), (-)-epicatechin (EC) and (-)-epigallocatechin gallate (EGg), on scavenging 1,1-diphenyl-2-picrylhydrazyl radical, superoxide anion radical and hydroxyl radical were examined by using colorimeter, chemiluminescence reader and ESR spectrometer, and the order of the scavenging activity was EGg>>EC≒CA. In order to examine the effects of tea catechins on the protection of neuronal injury by active oxygens, cultured newborn-mouse cerebral neurons were injured by hypoxanthine/xanthine oxidase (HPX/XOD) or glucose oxidase (GOD). EGg was strongest in the protection of the cell injury by HPX/XOD, but weakest in that by GOD. The memory impairment of mice was produced by 10 min occlusion of the bilateral common carotid arteries. Learning ability of mice was assessed by a step-down-type passive avoidance test. The i.v. injection of CA or EC ameliorated the memory impairment, but EGg did not. These results suggests that the in vivo activity of tea catechins on the protection against active oxygen injury greatly dependent on their permeability to cell membrane. Tea catechins like EC and CA that can scavenge intra- and extra-cellular active oxygen species may be useful in ameliorating the various diseases induced by active oxygens.