Protective Effect of Ethanolic Extract of Djulis Hull on Indomethacin-Induced Gastric Injury

Djulis (Chenopodium formosanum), a pseudocereal crop native to Taiwan, is often utilized as a source of grain in the diet because of its high nutritional value. The hull of djulis is discarded as waste during cooking or processing because of its bitter taste. However, recent studies have shown that djulis hull possesses certain benefits, such as antioxidant, blood sugar-lowering, and gut microbiota-regulating properties. Herein, the gastroprotective activity of ethanolic extract of djulis hull (EEDH) against stomach injury caused by indomethacin (IND) in C57BL/6J mice and its mechanism of action was assessed. Preadministration of EEDH significantly attenuated the gastric ulcer caused by IND in a dose-dependent manner (p < 0.05). Additionally, gastric mucosal injury and gastric wall edema within the submucosal layer observed in histopathological examination were improved by administration of EEDH. EEDH preadministration also reinstated the reduction of glutathione (GSH) content and catalase (CAT), and superoxide dismutase (SOD) activities induced by IND, indicating that EEDH can modulate the antioxidant status of gastric mucosa in mice. Moreover, IND-induced decline of gastric COX-1 expression was upregulated in mice of EEDH treatment groups. Administration of IND increased the expression of proinflammatory proteins in the gastric mucosa of mice, including tumor necrosis factor-alpha (TNF-alpha) and inducible nitric oxide synthase (iNOS), whereas EEDH treatment significantly decreased their expression (p < 0.05). Consequently, EEDH can improve gastric injury by regulating antioxidant status and inhibiting proinflammatory signaling pathways, and has the potential to be developed as a functional food for gastric protection.