Antinociceptive activity of the ethanolic extract of Trixis angustifolia DC.

The antinociceptive activity of the ethanolic extract of Trixis angustifolia DC. (EETx) was investigated using the acetic acid-induced writhing and the hot-plate tests in mice. In the acetic acid-induced writhing test, mice treated with EETx (50, 100 and 200 mg/kg, p.o.) exhibited reduced writhing (38%, 67%, and 74%, respectively). In the hot-plate test, the three doses administrated increased the nociceptive response time. The phytochemical analysis of EETx led to the isolation of three known compounds, hygric acid ( 1 ), 5,6-Dihydroxy-7,8,4'-trimethoxyflavone ( 2 ) and xanthomicrol ( 3 ). Compound 1 was identified for the first time in this species. These results demonstrate that T. angustifolia has potential central and peripheral antinociceptive effects and support the ethnomedicinal use of this plant.