Evaluation of the antinociceptive properties from Brillantaisia palisotii Lindau stems extracts.

Brillantaisia palisotii Lindau is a plant belonging to Acanthaceae family and it is widely found in tropical regions. Some species of this family are used in the folk medicine to treat several disorders, mainly those that involve analgesic processes. In this work it was evaluated antinociceptive activities of dichloromethane, ethyl acetate and n-butanol extracts obtained from Brillantaisia palisotii stems in peripheral (acetic acid-induced writhing) and central (tail flick and hot plate) analgesic models. All three extracts significantly inhibited the total number of writhing in a dose dependent manner. A spinal antinociceptive effect was observed with all three extracts and with similar patterns to all doses (1-30 mg/kg). Although ethyl acetate extract did not demonstrate supra-spinal activity, the effects observed with dichloromethane extract showed analgesic effect with all doses. The n-butanolic extract had activity only with the lowest dose (1 mg/kg). Our results indicate that all extracts from Brillantaisia palisotti stems develop peripheral and spinal analgesic activity, being the dichloromethane extract the only one with supra-spinal analgesic effect.