Croton cajucara BENTH. (Euphorbiaceae), commonly known as "sacaca," is widely used as an aromatic and bitter tea made from the bark and leaves of a plant in Amazonian folk medicine for the treatment of a wide range of gastrointestinal symptoms. 1,2) We also reported the antiulcerogenic activity of DHC (trans-dehydrocrotonin), the principal furano diterpene isolated from C. cajucara bark, on indomethacin-, hypothermic restraint-stress-, ethanol-and pylorus ligature-induced gastric ulcers in mice

more »

... and rats. 3) We also studied possible antiulcerogenic mechanisms involved in the action of DHC. 4) The acute and subchronic toxicity of this compound was also studied by our group through both in vivo and in vitro assays showing oral toxicity when administered for a short period of time (35 d). 3,5) Besides DHC, we also studied the antiulcerogenic activity of other diterpenes with a clerodane skeleton such as cordatin and aparisthman with excellent results. 6,7) We describe here the isolation of the second most important nor-clerodane diterpene from the bark of this plant, crotonin, and our study of its antiulcerogenic activity on indomethacin/bethanechol-, hypothermic restraint-stress-and pylorus ligature-induced gastric ulcer in mice. In the HCl/ethanol model, we studied whether the effect of crotonin was dose-dependent compared with that of cimetidine. The parameters of gastric-acid secretion such as gastric acidity and gastric-juice volume were analyzed in animals submitted to the Shay method and treated with crotonin by the oral and intraduodenal route. Moreover, the effects of crotonin on free mucus production were also determined. Data for DHC was also included for comparison in all experiments. Regarding the structure activity relationship, by comparing the antiulcerogenic activity of DHC and crotonin, we can evaluate the importance of parts of both molecules for the bioactivity tested.