30 - Antioxidant Properties of Crassostera gigas Oyster Extract

Abstract

Studies indicate that Japan Clinic Oyster Extract (JCOE) directly scavenges superoxide and hydroxyl radicals, and that a 24-hr pre-incubation with JCOE significantly protects RGM-1 cells against H202- or HOCl-induced injury. Its protective effect is not attributed to its direct free-radical scavenging activity, but is mediated by accelerating intracellular GSH synthesis. Oxygen radicals have been implicated as mediators of tissue injury associated with ischemia or inflammation. Studies using animal models have established that some antioxidants, including superoxide dismutase (SOD), superoxide radical scavenger, dimethyl sulfoxide (DMSO), hydroxyl radical scavenger, and several synthetic oxygen radical scavengers, are effective in the treatment and prevention of these diseases. Therefore, a new therapeutic approach using agents with antioxidant properties has been proposed. Natural food with free-radical scavenging activities is one of the candidates for preventing these tissue injuries. JCOE is an amino-acid powder extracted from Crassostera gigas, which has a high content of glutamic acid and taurine. According to the results of tests conducted by the Japan Food Analysis Center, JCOE contains a variety of substances having antioxidant activity, including thiol-containing amino acids, especially taurine. This chapter reviews previous data on the free-radical scavenging activity of JCOE and the protective effect of JCOE against gastric mucosal-cell injury induced by reactive oxygen species, and presents findings about the mechanism of cytoprotective effect by JCOE.