Antiinflammatory activity of Synurus deltoides.

Synurus deltoides Aiton, Nakai, is an edible plant that has been used as a folk medicine for treating inflammatory disorders. This investigation was carried out to establish the antiinflammatory activity of this plant material using a 75% ethanol extract from the aerial part of S. deltoides. Against the acute inflammatory animal model of mouse croton oil-induced ear oedema assay, the extract did not show significant inhibition at 100-800 mg/kg by oral administration. On the other hand, the extract showed considerable inhibition against the chronic inflammatory animal model of rat adjuvant-induced arthritis (25% inhibition at 100 mg/kg/day) while prednisolone exerted 40% inhibition at 10 mg/kg/day. In addition, S. deltoides possessed strong analgesic activity (IC50 = 50 mg/kg) in the acetic acid-induced writhing test. From the extract, ursolic acid and scopoletin were successfully isolated and their contents were found to be 0.31% and 0.37% (w/w), respectively, based on the dried extract by HPLC analysis. All the results obtained indicate that this plant material may be used beneficially as an antiinflammatory agent having analgesic action.