Gastric cytoprotective activity of Teucrium stocksianum extract in rats

The preventive effects of Teucrium stocksianum (lyophilized water extract) on ulcer formation induced by severe necrotizing agents such as absolute alcohol, 60% ethanol in 150 mM HCl (HCl-ethanol), and 0.2 N NaOH were studied in rats. T. stocksianum when given orally (p.o.) but not intraperitoneally exhibited a dose-dependent gastric cytoprotective effect to the three necrotizing agents tested. The mucosal protective action of T. stocksianum was attenuated by pretreatment with indomethacin (5 mg/kg, subcutaneously). T. stocksianum (500 mg/kg twice per day, p.o.) had no significant effect on the healing process of ethanol-induced gastric ulcers 24,48 and 72 h after ulcer induction. T. stocksianum (500 mg/kg, p.o.) did not afford protection against cysteamine-induced duodenal ulceration. In vitro studies showed that T. stocksianum dose-dependently inhibited ethanol-induced contractions of rat fundic strip muscles. This effect was abolished by the cyclooxygenase inhibitor, indomethacin. In addition, T. stocksianum dose-dependently inhibited acetylcholine-induced contraction of guinea-pig ileal smooth muscles. The gastric cytopreventive activity of T. stocksianum and its failure to protect against duodenal ulceration is discussed in relation to its pharmacological mechanism of action and to the pathogenic mechanism of action of the ulcerating agents used.