Preventive activity of pyrrolizidine alkaloids from Seneciobrasiliensis (Asteraceae) on gastric and duodenal induced ulcer on mice and rats.

The alkaloid extract of Senecio brasiliensis inflorescences contain a mixture of the pyrrolizidine alkaloids (PA) senecionine, integerrimine, retrorsine, usaramine and seneciphylline. We evaluated this PA mixture on preventive antiulcerogenic effects on standard rodent models of induced gastric and duodenal ulcers. In the HCl/ethanol, indomethacin-bethanechol and hypothermic-restraint-induced gastric ulcer, the lesion was significantly inhibited by PA (p.o.) (p < 0.001). In the pylorus-ligature, PA (i.d.), significantly increased the gastric juice content and the pH values and decreased the acid output. In the cysteamine induced duodenal ulcers, PA (p.o.) showed significant inhibition (p < 0.001) of the duodenal lesions when compared to the respective control. The levels of the somatostatin hormone in the blood samples of animals pre-treated with the PA (12.5 mg/kg) and the free mucus and prostaglandin synthesis also increased (p < 0.001) after administration of PA extract (p.o.). The results suggested that the PA extract from Senecio brasiliensis inflorescences presents a significant anti-ulcer effect in the selected ulcer models. The mechanism involved with the action of the PA extract is the cytoprotection. Additional studies are in progress to determine other possible mechanisms involved with effect of the PA as anti-ulcer agents.