Antiinflammatory and antipruritic effects of Solanum trilobatum L. fruit extracts

Abstract

The fruits of Solanum trilobatum L. (Thai name: mawaeng krueo), a shrub of the family Solanaceae, were extracted with water (aqueous extract), 95% ethanol (ethanolic extract) and 95% ethanol: HCl (10:1) (partially purified extract). The extracts were tested for anti-inflammatory activity in mice using a topical model and peritoneal inflammatory models. The ethanolic extract was also tested for antipruritic activity. Thetopical model was designed to evaluate the effectiveness of the extracts for both preventive and curative activity against ethyl- phenylpropiolate (EPP)-induced ear edema. All substances were applied topically on the inner and outer surface of a mouse's ear. Pretreatment with either one of the three ex tracts mentioned above (0.5, 1 and 2 mg/ear) two hours before EPP application prevented ear ed ema in a dose-dependent manner. The ear edema was also significantly suppressed in a dose dependent manner (P<0.01) when the extract (0.5, 1 and 2 mg/ear for the aqueous and the ethanolic extract and 0.25, 0.5 and 1 mg/ear for the partially purified extract) was a pplied one hour after EPP application. Both the preventive and curative effects of the extracts lasted throughout the observation period (four hours) and were comparable to the results obtai ned with the reference antiinflammatory drug (dexamethasone, 0.05 mg/ear). Two peritoneal inflammatory mode ls, i.e. acetic acid-induced vascular permeability and carrageenan-induced leukocyte migration, we re selected for the testing of internal antiinflammatory activity of the extracts. Oral ad ministration of the etha nolic extract (200, 400 and 600 mg/kg) significantly exhibited an antiinfl ammatory effect (P<0.001) in both models. However, the extract at all the doses tested was less potent than the two reference antiinflammatory drugs (dexamethasone, 1 mg/kg and indomethacin, 10