Gastroprotective effect of polysaccharides from Agaricus blazei Murill against ethanol-induced gastric ulcer in mice.

This study aims to isolate and characterize the physicochemical properties and evaluate the cytoprotective and gastroprotective potential of polysaccharides from the Agaricus blazei Murill mushroom (PAbM). The PAbM were isolated and characterized chemically. The cytoprotective potential of PAbM was studied using LLC-MK2 cells through the acetic acid-induced cell injury model. The gastroprotective activity was studied using the ethanol-induced gastric ulcer model. The PAbM showed a molecular mass of 4.7 × 105 g mol-1 and polydisperse character, being composed by glucose, mannose and galactose monomers. In vitro study showed the low cytotoxicity of PAbM against LLC-MK2 cells and their ability to attenuate cellular injury (3.12 and 6.25 μmol/L) caused by exposure to acetic acid, being able to reduce the parameters related to oxidative stress and prevent the occurrence of cellular alterations. The in vivo assay demonstrated the ability of PAbM (50 and 150 mg/kg, p.o.) to alleviate the morphological changes in the gastric mucosa induced by the administration of ethanol. PAbM were able to reduce tissue mastocytosis and these results were more promising than those obtained for reference drug (carbenoxolone at 200 mg/kg, p.o.). The administration of PAbM was able to reduce TBARS levels and increase GSH levels, evidencing their in vivo antioxidant activity. Thus, this study reports the gastroprotective potential of PAbM and encourages future studies in the preclinical context to better understand the mechanisms linked to this activity and their use in clinical trials aimed at a new treatment for gastric ulcer.