Effects of Crystalline and Amorphous Forms of Paramylon from Euglena gracilis on the Development of Water-immersion Restraint Stress-induced Gastric Ulcer

Background: β-Glucans reportedly inhibit gastric ulceration; however, it is unclear which form of the polysaccharide is important for this inhibitory effect. In this study, the effect of paramylon from Euglena gracilis (β-(1,3)-glucan) on gastric ulcers was evaluated. Materials and methods: Wistar rats were exposed to water-immersion restraint stress (WIRS). Results: Dietary intake of Euglena extract powder, paramylon (insoluble), and amorphous paramylon (soluble) decreased the area of gastric ulceration in comparison with the control group. WIRS-induced increases of inducible nitric oxide synthase expression in the gastric mucosa and serum IgA and alanine aminotransferase levels were suppressed in rats fed with Euglena extract powder, paramylon, or amorphous paramylon. These results indicate that paramylon and amorphous paramylon suppressed gastric ulcers, presumably by reducing oxidative damage resulting from WIRS. In addition, our data suggest that Euglena extract powder, paramylon, and amorphous paramylon prevent the WIRS-induced influx of proinflammatory molecules from the gut.