Gastroprotective effects of thymol on acute and chronic ulcers in rats: The role of prostaglandins, ATP-sensitive K(+) channels, and gastric mucus secretion.

Abstract Thymol, a monoterpene phenol derivative of cymene, is found in abundance in the essential oils of Thymus , Origanum , and Lippia species. The present study investigated the gastroprotective actions of thymol (10, 30, and 100 mg/kg, p.o.) in the acute (ethanol- and nonsteroidal anti-inflammatory drug-induced ulcers) and chronic (acetic acid-induced ulcers) ulcer models in rats. Some of the mechanisms underlying to the gastroprotective effect of thymol were investigated in the ethanol-induced ulcer model. Gastric secretion parameters (volume, pH, and total acidity) were also evaluated by the pylorus ligature model, and the mucus in the gastric content was determined. The anti- Helicobacter pylori activity of thymol was performed using the agar-well diffusion method. Thymol (10, 30, and 100 mg/kg) produced dose dependent reduction ( P P + channel blocker, 10 mg/kg), but not by dl -Propargylglycine (PAG, a cystathionine-γ-lyase inhibitor, 25 mg/kg) and N w -nitro- l -arginine methyl ester hydrochloride ( l -NAME, a non-selective inhibitor of nitric oxide synthase, 70 mg/kg). Thymol (30 and 100 mg/kg) also reduced the ulcer index ( P P P H . pylori activity in vitro . Collectively, the present results provide convincing evidence that thymol displays gastroprotective actions on the acute and chronic ulcer models through mechanisms that involve increased in the amount of mucus, prostaglandins, and ATP-sensitive K + channels.