Effects of mycelial culture of Phellinus linteus on ethanol-induced gastric ulcer in rats.

The gastroprotective effects of a mycelial culture of Phellinus linteus (MCPL) were evaluated by determining the ulcer index, gastric mucus content, histopathological observation and histochemical properties of mucin in an ethanol-induced ulcer model of rats. Preadministration with MCPL at doses of 20 and 60 mg/kg, showed a significant decrease of bleeding and ulcer index and alleviated the histopathological changes induced by ethanol such as hemorrhage and necrosis. Ethanol treatment decreased the gastric adhesion mucus content, but a higher level of gastric mucus persisted after preadministration of MCPL. As for the histochemical properties of mucins, marked changes were observed in both the surface and gland mucous cells in ethanol-treated rats, but these changes were detected only in the surface mucous cells in rat preadministered with MCPL. Using conventional methods for mucins, ethanol-treated rats revealed a decrease of neutral and acid mucin in the surface epithelium and mucous neck cells compared with normal rats. A marked decrease of BSL-1 by lectin histochemistry was also revealed in the ethanol-treated rats. But the MCPL preadministered rats showed similar stainabilities and lectin affinity patterns for mucins as the normal rats. These results indicate that pretreatment with MCPL provided protection of the gastric mucosa from ethanol-induced injury by maintaining the mucus barrier in rats.

Induction of apoptotic cell death by mycelium extracts of Phellinus linteus in human neuroblastoma cells.

Phellinus linteus is a well-known Oriental medicinal fungus that has various biological activities, including immunomodulatory and anti-tumor activities, the mechanisms of which are poorly understood. In the present study, we investigated the effects of mycelium extracts of P. linteus (MEPL) on the growth of human neuroblastoma SK-N-MC cells. Upon treatment with MEPL, a concentration-dependent inhibition of cell proliferation was observed and cells developed many of the hallmark features of apoptosis, including condensation of chromatin and an increase in the sub-G1 population. The anti-proliferative and apoptotic effects of MEPL were associated with a marked induction of the Bax and cyclin-dependent kinase inhibitor p21. Western blotting and in vitro caspase-3 activity assay demonstrated that the processing/activation of caspases accompanies the generation of MEPL-mediating apoptotic cell death. In addition, the proteolytic cleavage of specific target proteins such as poly(ADP-ribose) polymerase and beta-catenin were observed. Taken together, the present results suggest that apoptotic signals evoked by MEPL in human neuroblastoma SK-N-MC cells may converge caspase-3 activation through an up-regulation of Bax rather than a down-regulation of Bcl-2.