ABSTRACT
The antinociceptive activity of the Maytenus rigida Mart. (Celastraceae) ethanol extract and its ethyl acetate fraction as well as of (-)-4'-methylepigallocatechin (1), a previously isolated compound, was demonstrated in vivo. ED50 for 1 in the writhing test was 14.14 mg/kg. The acetic acid-induced writhing was inhibited by 98.4, 84.4, and 58.3%, respectively, when mice were treated with the ethanol extract, ethyl acetate fraction, and 1. In the hot plate test, mice pretreated with 1 showed significantly increased reaction times (60-89%). Oral administration of 1 significantly inhibited first and second phases of the formalin-induced pain (50 and 26.5%, respectively), whereas indomethacin inhibited only the second phase of the test (41.2%). Ethanol extract and its fraction showed effects on inflammatory pain, while neurogenic and inflammatory pain suppression by 1 is a strong indication of the presence of both central and peripheral effects and suggests its analgesic and anti-inflammatory potential.