Gastroprotective activity of Loranthus acaciae flower extract in a rodent model of ethanol-induced ulcer.

Loranthus acaciae (Loranthaceae) is a perennial green semi-parasitic plant used in ethnopharmacological medicine for healing wounds. The protective effect of L. acaciae on gastric ulcer induced by ethanol was investigated in a rat model. Ulcer index and total glutathione level were measured, histological and immunohistochemical studies for the expression of cyclooxygenase-2 were performed. Furthermore, chemical constituents of the flower extract were analyzed. Ulcer index was significantly lowered in L. acaciae treated groups. Protection ratios were 75.9%, 98.9% and 70.7% for L. acaciae 250 mg/kg, 500 mg/kg, and esomeprazole 40 mg/kg, respectively. Histological examination revealed fewer hemorrhage in mucosa and less edema in submucosa in L. acaciae treated groups compared to control. In esomeprazole-treated group, there was mild disruption in the surface epithelium and mild hemorrhage. However, edema and leucocytes infiltration in the submucosa layer were present. Immunohistochemical staining of stomach sections for cyclooxygenase-2 was negative in control group as well as in L. acaciae treated groups. Total glutathione level in mucosa layer of the stomach was higher in L. acaciae treated groups compared to control. LC-MS analysis revealed the presence of loranthin and rutin as the major constituents. It can be concluded that L. acaciae imparted a gastroprotective action against ethanol induced ulcer in rats. Key points 1. 500 mg/kg L. acaciae protected the stomach by 98.9% from ulcerogenic effect of ethanol. 2. L. acaciae increased total glutathione level but not COX-2 expression in gastric mucosa. 3. Loranthin and rutin were the major constituents in L. acaciae flower extract.