Effect of pleuran (beta-glucan from Pleurotus ostreatus) on the antioxidant status of the organism and on dimethylhydrazine-induced precancerous lesions in rat colon.

The effect of pleuran (beta-1,3-D-glucan isolated from the oyster mushroom Pleurotus ostreatus) on the antioxidant status of the organism and on the development of precancerous aberrant crypt foci (ACF) lesions in the colon is studied in the male Wistar rat. A diet containing either 10% pleuran or 10% cellulose was compared with a cellulose-free diet and both were found to significantly reduced conjugated diene content in erythrocytes and in liver. Particularly significant was the reduction of conjugated dienes in the colon following pleuran administration. Diets containing cellulose and pleuran reduced glutathione peroxidase (GSH-PX) activity and increased catalase activity in erythrocytes. Pleuran increased superoxide dismutase (SOD) and GSH-PX activity (compared with the cellulose diet), and glutathione reductase activity (compared with the cellulose-free diet) in liver; and both diets reduced glutathione levels significantly in the colon. ACF lesions developed in the colon of all animals fed a cellulose-free diet; however, the incidence was reduced to 64% and 60% following the cellulose and pleuran diets, respectively. The highest average count of the most frequent small ACF lesions--and highest total count--was seen in animals fed a cellulose-free diet. Although ACF lesions were reduced by the cellulose diet, the more significant reduction statistically (>50%) was achieved with the pleuran diet.