Role of endogenous prostaglandins in gastroprotection of β-sitosterol and four derivative esters on ethanol-induced gastric mucosal lesions in rats

In this investigation, the gastroprotective activity of four esters of β-sitosterol (succinate, phthalate, benzoate and acetate) was evaluated. Gastric mucosal damage was induced in rats by intragastric ethanol (1 ml/rat). Rats treated orally with these compounds suspended in Tween® 80 showed significant gastroprotective effects (38 to 75% gastroprotection). The gastroprotection observed at 30 mg/kg for β-sitosterol succinate, phthalate and benzoate was attenuated in rats pretreated with indomethacin (10 mg/kg), suggesting that the gastroprotective mechanism of these esters involves, at least in part, the participation of prostaglandins. The gastroprotective effect of the acetate was not affected by the inhibition of prostaglandins synthesis with indomethacin. Carbenoxolone was used as gastroprotective model drug and showed dose dependent gastroprotective effect (25, 43 and 88% gastroprotection, at 3, 10 and 30 mg/kg, respectively). The partial participation of prostaglandins was observed in the gastroprotective mechanism of carbenoxolone. In addition, these results suggested that gastroprotective activity of β-sitosterol is not modified for the introduction of succinyl, phthalyl, benzoyl or acetyl groups at C-3.