Free radical-scavenging activity of Crassostera gigas extract (JCOE).

In the present study, we evaluate the free radical-scavenging activity of JCOE (Japan clinic oyster extract), a powder extracted from Crassostera gigas by a spin-trapping method using electron paramagnetic resonance (EPR), and also estimate the protective effect against gastric mucosal cell injury induced by hydrogen peroxide. The EPR study demonstrated that JCOE directly scavenged superoxide radical as well as hydroxyl radical in a concentration-dependent manner. After exposure to hydrogen peroxide for 4 h in Hank's balanced buffered solution, cell viability of rat gastric mucosal cells (RGM-1) was measured by modified MTT assay. Hydrogen peroxide-induced injury was not reversed by 1-h preincubation with 100 to 1,000 micrograms/mL JCOE solution which has high reactivity to hydroxyl radicals, indicating that the active ingredients, including taurine of JCOE on scavenging action of hydroxyl radical, did not penetrate cell membranes easily. Twenty-four hour pretreatment with the JCOE solution significantly reversed the decrease in cell viability induced by hydrogen peroxide, indicating the possibility that JCOE solution may stimulate the endogenous eliminating system against hydrogen peroxide.