Chronic central and peripheral analgesic activity of ethanolic extract of the leaves of clerodendrum viscosum in rodent models.

ABSTRACT

The aim of the study was to investigate the chronic peripheral analgesic activity of Ethanolic Extract of the leaves of Clerodendrum viscosum (EECV) by acetic acid induced writhing reflex test in mice and chronic central analgesic activity of EECV by tail immersion method in rats. Dried powdered leaves of Clerodendrum viscosum were subjected to solvent extraction by using 90 % ethanol. Based on acute oral toxicity study according to Organization for Economic Cooperation and Development (OECD) guidelines No. 423, three doses of the test drug was selected and were subjected to chronic analgesic activity. EECV showed significant chronic peripheral analgesic activity (p<0.01) in mice in the dose of 200 mg / kg and moderate analgesic activity at the dose of 400 mg/kg (p<0.05) as compared to control and the standard drug Indomethacin. But failed to show any chronic central analgesic activity by tail immersion method at any of the three doses selected compared to control and standard drug Pentazocin in rats.