Antinociceptive effects of the tubercles of Anredera leptostachys.

The tubercles of Anredera leptostachys are used as an antinociceptive and anti-inflammatory in the popular medicine of the Caribbean basin. In the present work, the anti-nociceptive and central nervous system depressant (CNS) effects of the methanolic extract from the tubercles of A. leptostachys have been evaluated. The antinociceptive activity was assayed in several experimental models in mice: acetic acid, formalin and hot plate tests. The methanolic extract (250 and 500 mg/kg) significantly and in a dose-dependent manner reduced the nociception induced by the acetic acid (P < 0.001). In the hot plate test, the extract significantly increased the latency time of jump 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 painful stimulus but the effect was not dose-dependent. In the study of the CNS-depressant effects, the extract was found to produce a significant reduction of the exploratory capacity with both doses assayed (P < 0.001). The muscular relaxation only decreased with the higher doses assayed (P < 0.001). The escape instinct was also significantly reduced (P < 0.001) by the two doses of the extract and both were more effective than standard drugs morphine and diazepam.