Acute Toxicity, Antisecretory Activity and Proton Pump (H+/K+ - ATPase) Inhibitory Potential of Methanol Leaf Extract of Saccharum spontaneum in Aspirin-induced Gastric Lesions

Gastric ulceration is associated with excessive gastric acid secretion and impaired mucosal defence, while non-steroidal anti-inflammatory drugs such as aspirin are important causes of gastric mucosal injury. Saccharum spontaneum has traditionally been used in the management of gastric disorders, but evidence regarding its antisecretory activity and direct inhibition of gastric H⁺/K⁺-ATPase remains limited. This study evaluated the acute oral toxicity, gastroprotective and antisecretory effects, and H⁺/K⁺-ATPase inhibitory potential of the methanol leaf extract of S. spontaneum in aspirin-induced gastric lesions in rats. Acute toxicity was assessed using Lorke’s method at doses of 10–5000 mg/kg body weight, while gastroprotective activity was evaluated in 30 rats allocated to five groups and treated with the methanol extract at 200 and 400 mg/kg for 14 days, with omeprazole (10 mg/kg) used as the standard drug. Gastric volume, pH, free acidity, and total acid output were determined, while inhibition of gastric H⁺/K⁺-ATPase was assessed in vitro at concentrations of 10–200 μg/mL. No mortality was observed following administration of the extract up to 5000 mg/kg, indicating an LD₅₀ greater than 5000 mg/kg. Aspirin markedly increased gastric secretion and acidity, whereas treatment with the extract reduced gastric volume and acidity and increased gastric pH in a dose-dependent manner. Gastric volume decreased from 3.15 ± 0.30 mL in the aspirin group to 2.31 ± 0.70 and 2.06 ± 0.62 mL following treatment with 200 and 400 mg/kg of the extract, respectively, while gastric pH increased from 2.01 ± 0.14 to 4.45 ± 0.62 and 5.24 ± 0.59, respectively. The extract also inhibited gastric H⁺/K⁺-ATPase activity in a concentration-dependent manner, producing 61.05% inhibition at 200 μg/mL compared with 86.67% for omeprazole. The IC₅₀ values were 116.41 ± 41.98 μg/mL for the extract and 37.79 ± 0.10 μg/mL for omeprazole. These findings demonstrate that the methanol leaf extract of S. spontaneum possesses an acute oral safety profile, gastroprotective and antisecretory activities against aspirin-induced gastric lesions and may contribute to suppression of gastric proton-pump activity. The extract therefore represents a promising source of bioactive compounds for further investigation in anti-ulcer drug discovery.