Hepatoprotective effect of extracts from Lentinus edodes mycelia on dimethylnitrosamine-induced liver injury

Biological and Pharmaceutical Bulletin

Mycelia of the edible mushroom Lentinus edodes (shiitake) were cultivated in a solid medium, and two frac- tions were obtained by hot-water extraction (L.E.M.) and then ethanol extraction followed by Sephadex LH-20 column chromatography (ESMe). The L.E.M. and ESMe were then examined for their hepatoprotective effect on dimethylnitrosamine-injured mice. Both fractions decreased the blood aspartate aminotransferase and alanine aminotransferase levels, partially inhibited the overaccumulation of collagen fibrils, and suppressed the overex- pression of genes for -smooth muscle actin and/or heat-shock protein 47 in the mice. Both fractions also inhib- ited the morphologic change and proliferation of isolated rat hepatic stellate cells (HSCs), which play a central role in liver fibrosis, in a dose-dependent manner and without cytotoxicity. The direct interaction between the extracts and HSCs appears to be important for the hepatoprotective activity. Polyphenols contained in both frac- tions are considered to be potential candidates for expressing the hepatoprotective effects. The finding of antifi- brotic activity in extracts from an edible mushroom is expected to be helpful in the development of hepatoprotec- tive agents with few side effects