A hydro-ethanolic extract of Synedrella nodiflora (L.) Gaertn ameliorates hyperalgesia and allodynia in vincristine-induced neuropathic pain in rats

BACKGROUND: The hydro-ethanolic extract of Synedrella nodiflora (L.) Gaertn whole plant has demonstrated analgesic effects in acute pain models. The extract has also demonstrated anticonvulsant effects in murine models of experimental epilepsy. The present study illustrates an evaluation of the hydro-ethanolic extract of the plant for possible analgesic properties in hyperalgesia and allodynia associated with vincristine-induced neuropathy in rats. METHODS: Neuropathic pain was induced in Sprague-Dawley rats by injecting 100 μg/kg of vincristine sulphate on alternative days for 6 days (days 0, 2, 4, 8, 10 and 12). Vincristine-induced cold allodynia, mechanical hyperalgesia and thermal hyperalgesia were measured pre-vincristine administration and on days 15, 17 and 19 post-vincristine administration. The rats were then treated with S. nodiflora extract (SNE) (100, 300 and 1000 mg/kg), pregabalin (10, 30 and 100 mg/kg) and distilled water as vehicle daily for 5 days and pain thresholds were measured on alternate days for 3 days. RESULTS: SNE and pregabalin produced analgesic properties observed as increased paw withdrawal latencies to mechanical, tactile, cold water stimuli and thermal hyperalgesic tests during the 5 days of treatment. CONCLUSIONS: The findings suggest that hydro-ethanolic extract of S. nodiflora possesses anti-hyperalgesic and anti-allodynic effects in vincristine-induced neuropathic pain in rats.