Antinociceptive and Anti-Inflammatory Activities of Methanol Root Extract of <i>Tetracera potatoria</i>

Abstract

Methanol root extract of Tetracera potatoria was evaluated for anti-inflammatory and analgesic activities. The inflammatory activity of the extract was assayed by egg-albumen induced paw oedema and formalin paw lick test in rats whereas its analgesic activity was determined by its effects on acetic acid-induced abdominal writhing, hot plate and tail flick tests in mice. Each of the experiments consisted of twenty five animals randomly, but equally divided into 5 groups of 100, 300 or 500 (mg kg^-1) body weight extract pre-treated, Indomethacin pre-treated (10 mg kg^-1 b.w) and a control group administered with distilled water (10 mL Kg^-1 b.w). At the 30, 60 and 90 minutes post-injection of albumen observation periods, there was significant (p<0.05) inhibition of egg-albumen induced paw oedema in rats pre-treated with extract of T. potatoria especially 500mg/kg b.w (69.4, 64 and 76%) compared with rats in the control group and Indomethacin-pretreated rats (18.4, 24 and 32%). Itching of the paws persisted significantly (p<0.05) longer in the control or Indomethacin-treated rats than in T. potatoria pre-treated for both phases of formalin-induced paw licks. Extract-treated animals exhibited significantly (p<0.05) lower number of writhings in response to acetic acid induced writhing movement. The analgesic effect of the extract (100, 300 or 500mg kg^-1) in hot plate test was observable within 60 minutes of administration and maximum effect obtainable 120 minutes post-administration, just as pre-treated mice tolerated thermal pain longer than the Indomethacin-pretreated counterpart in tail flick test. Findings from this study showed that extract of T. potatoria possess anti-inflammatory and analgesic potencies most probably via the central and peripheral mechanisms. Isolation and chemical characterization of the bioactive compound in this plant is warranted and therefore recommended as further studies...

Keywords: Tetracera potatoria, anti-inflammatory, analgesic, mice, rats