Antinociceptive effects of the tubercles of Anredera leptostachys

The tubercles of Anredera leptostachys are used as an antinociceptive and a nti-inflammatory in the popular medicine of the Caribbean basin. In the pre sent work, the anti-nociceptive and central nervous system depressant (CNS) effects of the methanolic extract from the tubercles of A. leptostachys ha ve been evaluated. The antinociceptive activity was assayed in several expe rimental models in mice: acetic acid, formalin and hot plate tests. The met hanolic extract (250 and 500 mg/kg) significantly and in a dose-dependent m anner reduced the nociception induced by the acetic acid (P < 0.001). In th e hot plate test, the extract significantly increased the latency time of j ump although it slightly increased the licking time. The naloxone partially reversed the antinociception of the extract in the hot plate test. In the formalin test, the methanolic extract also significantly reduced the painfu l stimulus but the effect was not dose-dependent. In the study of the CNS-d epressant effects, the extract was found to produce a significant reduction of the exploratory capacity with both doses assayed (P < 0.001). The muscu lar relaxation only decreased with the higher doses assayed (P < 0.001). Th e escape instinct was also significantly reduced (P < 0.001) by the two dos es of the extract and both were more effective than standard drugs morphine and diazepam. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.