Antinociceptive andAntiinflammatory Effect of a Diterpene Isolated from the Aerial Part of Siegesbeckia pubescens

Abstract

TheaerialpartofSiegesbeckiapubescens(Compositae)hasbenusedtotreatrheumatoidarthritisandhypertensionintheOriental medicine. This crude drug has been used without process (SP-0) or with thre times-process of steaming and drying (SP-3)ity-directedfractionationwasperformedonthiscrudedrug. SincetheCHCl3extractwashowntohaveamorepotentefectthanoth-er extracts, it was subjected to silica gel & ODS column chromatography to yield two diterpene compounds (1). Compound1 wasstructuraly identified as ent-16 (H,17-hydroxykauran-19-oic acid, which were tentatively named siegeskaurolic acid A. Amain di-terpene, siegeskaurolic acid A was tested for the antiflamatory antinociceptive effects using both hot plate- and writhing anti-and 30mg/kg) significantly reduced the stretching episodes, action time of mice and carrageenan-induced edema. These results up-port hat siegeskaurolic acid is a main diterpene responsible for antinociceptive and antiflammatory action ofS. pubescens. In addi-tion, theasaysonSP-0, SP-3andSP-9producedthexperimentalresultsthatSP-9hadmoresignificant efectsthanothertwocrudedrugs. These results uggest hat the processing on the original plant may lead to the higher pharmacological efectKey words-Siegesbeckia pubescens