Gastroprotective effect and mode of action of methanol extract of Sphenodesme involucrata var. paniculata (C.B. Clarke) Munir (Lamiaceae) leaves on experimental gastric ulcer models.

Sphenodesme involucrata var. paniculata (C. B. Clarke) Munir, endemic to South Asia, is used by tribal for alleviation from abdominal disorders, inflammation and body pain. However, the gastroprotective properties of this species have not yet been studied. The leaves of S. involucrata were extracted by Soxhlet extraction using different solvents successively and the extracts were analyzed for antioxidant and anti-Helicobacter pylori activities using different in vitro assays. The chemical composition of methanol extract of S. involucrata (MESi) was analysed by gas chromatography-mass spectrometry (GC-MS). The gastroprotective action of the MESi at the doses of 100, 200, and 400 mg/kg were evaluated in absolute ethanol, acidified ethanol (EtOH/HCl) and nonsteroidal anti-inflammatory drug (NSAID) induced rat experimental models. To elucidate the mode of antiulcerogenic action, the antisecretory parameters (gastric juice volume, pH, and total acidity) and the catalase (CAT) and superoxide dismutase (SOD) enzymes activity and malondialdehyde (MDA) level were evaluated in gastric ulcer tissue. Also the stomachs of the animals were subjected to histological assessment. MESi presented a high antioxidant activity in several oxidants in vitro systems (DPPH•, ABTS•+ and FRAP) and it demonstrated a good spectrum of inhibitory activity against H. pylori growth (MIC, 100 μg/mL). GC-MS analysis of MESi indicated the presence of twenty one compounds, among them phenol (21.84%), hexadecanoic acid (15.96%), (9E, 12E)-9, 12-octadecadienoyl chloride (11.15%) and palmitic acid-β-monoglyceride (8.80%) were found higher. MESi (100, 200 and 400 mg/kg, p.o.) produced significant reduction (p < 0.01) of lesion area in the ethanol, acidified ethanol and indomethacin-induced ulcer models. In the pylorus ligation induced ulcer model, the treatment with MESi significantly altered the gastric secretion by decreasing total gastric juice volume and gastric acidity as well as by increasing the gastric pH. MESi pre-treatment significantly (p < 0.05) restored the depleted activity of SOD, CAT enzymes and reduced MDA levels in the gastric tissue as well as the histological analysis of the stomachs of the animals showed that the MESi also prevents local action of offensive factors. Collectively, the present study results suggest that the methanol extract of S. involucrata leaves demonstrates gastroprotective action, supporting the folkloric usage of the plant to treat gastro-intestinal disturbances.