Gastroprotective effect of latex extract from Plumeria rubra in models of acute gastric lesion

Plumeria rubra (Apocynaceae), a laticifer plant, has been widely used in traditional folk medicine to treat various diseases. This study was performed to investigate the gastroprotective activity of a non-dialyzable protein fraction (PrLP) of P. rubra latex in gastric ulcer model. Experimental protocols were registered on the Institutional Ethics Committee under number 57/2010. Swiss male mice were treated with PrLP in doses 0.5; 5 and 50mg/kg (i.v.; n=8). After 30min they received 0.2ml of absolute ethanol per oral and after 60min, the animals were sacrificed and stomachs removed and analyzed the lesion index and dosage of GSH (reduced glutathione) and Nitrite. To study the gastroprotective mechanism(s), its relations to capsaicin-sensitive fibers, endogenous prostaglandins, nitric oxide, ATP-sensitive potassium channels and GMPc were analyzed. PrLP all doses prevented gastric injury (p<0.05). PrLP also restored the GSH levels and Nitrite in mucosa (p<0.05). Capsazepine, Indometacin, L-NAME, Glibenclamide and ODQ and were able to reverse the protective effect of PrLP (p<0.05). We can conclude that the PrLP has protective activity in the gastric mucosa, this protection appears to be mediated in part by modulation of prostaglandin/NO/Katp/GMPc/TRPV1 receptors and by antioxidant mechanisms.