Gastroprotective activity of methyleugenol from Peperomia Hispidula on ethanol-induced gastric lesions in rats

Peperomia hispidula is used in traditional Mexican herbal medicine to treat gastric ulcers. However, this use has not been corroborated scientifically. Hence, the gastroprotective activity of P. hispidula was herein evaluated, as well as the role of endogenous NO, sulfhydryl groups and prostaglandins in the gastroprotective effect shown by one compound. The activity of P. hispidula was evaluated by using an animal model of gastric lesions induced by absolute ethanol in Wistar rats. Methyleugenol was isolated via silica gel column chromatography. The cytoprotective mechanisms of this compound were evaluated in relation to nitric oxide (pretreatment with L-NAME), sulfhydryl groups (pretreatment with NEM) and prostaglandins (pretreatment with indomethacin). The hexane and dichloromethane extracts showed gastroprotective activity, the latter (at 100 mg kg^-1) having the greatest effect (91.55±3.12%). Methyleugenol was identified as one of the most active compounds in this extract. The gastroprotective activity of methyleugenol at 100 mg kg^-1 was not attenuated by pretreatment with L-NAME, NEM or indomethacin. Methyleugenol was identified as one of the compounds of P. hispidula that exerts a gastroprotective effect. The results suggest that the gastroprotective mechanism of methyleugenol does not involve nitric oxide, sulfhydryl groups or prostaglandins.