The gastroprotective effects of hydroalcoholic extract of Monolluma quadrangula against ethanol-induced gastric mucosal injuries in Sprague Dawley rats

Monolluma quadrangula (Forssk.) Plowes is used in Saudi traditional medicines to treat gastric ulcers. The hydroalcoholic extract of M. quadrangula (MHAE) was used in an in vivo model to investigate its gastroprotective effects against ethanol-induced acute gastric lesions in rats. Five groups of Sprague Dawley rats were used. The first group was treated with 10% Tween 20 as a control. The other four groups included rats treated with absolute ethanol (5 mL/kg) to induce an ulcer, rats treated with 20 mg/kg omeprazole as a reference drug, and rats treated with 150 or 300 mg/kg MHAE. One hour later, the rats were administered absolute ethanol (5 mL/kg) orally. Animals fed with MHAE exhibited a significantly increased pH, gastric wall mucus, and flattening of the gastric mucosa, as well as a decreased area of gastric mucosal damage. Histology confirmed the results; extensive destruction of the gastric mucosa was observed in the ulcer control group, and the lesions penetrated deep into the gastric mucosa with leukocyte infiltration of the submucosal layer and edema. However, gastric protection was observed in the rats pre-fed with plant extracts. Periodic acid–Schiff staining of the gastric wall revealed a remarkably intensive uptake of magenta color in the experimental rats pretreated with MHAE compared to the ulcer control group. Immunohistochemistry staining revealed an upregulation of the Hsp70 protein and a downregulation of the Bax protein in rats pretreated with MHAE compared with the control rats. Gastric homogenate showed significantly increased catalase and superoxide dismutase, and the level of malondialdehyde (MDA) was reduced in the rats pretreated with MHAE compared to the control group. In conclusion, MHAE exhibited a gastroprotective effect against ethanol-induced gastric mucosal injury in rats. The mechanism of this gastroprotection included an increase in pH and gastric wall mucus, an increase in endogenous enzymes, and a decrease in the level of MDA. Furthermore, protection was given through the upregulation of Hsp70 and the downregulation of Bax proteins.