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.
