Analgesic properties of the ethanol extract of leaves of Triumfetta cordifolia A. Rich

Triumfetta cordifolia is used ethnomedicinally in the management of pain, inflammatory and mental disorders. No study has been carried out to scientifically confirm its ethnomedicinal use in the management of pain. Hence, this study was design to evaluate the antinociceptive property of ethanol extract of leaves of T. cordifolia (EETC) in experimental models of pain in mice. The antinociceptive property of EETC (8.8, 17.5 and 35 mg/kg) administered intraperitoneally (i.p.) was assessed on acetic acid-induced abdominal writhing, formalin-induced paw licking, hot water tail immersion and hot plate-induced nociception tests. In addition, naloxone (1 mg/kg, i.p.) was used to elucidate the involvement of opioidergic system in the antinociceptive activity of EETC in hot plate test. EETC (8.8, 17.5 and 35 mg/kg, i.p.) significantly (p < 0.05) reduced acetic acid-induced writhing when compared with control. Also, EETC (8.8, 17.5 and 35 mg/kg, i.p.) dose-dependently attenuated formalin-induced paw licking; as it significantly (p < 0.05) inhibited the inflammatory phase, although only EETC (35 mg/kg, i.p.) was found to suppressed the neurogenic phase. Moreover, EETC significantly (p < 0.05) increased the reaction time to pain in mice exposed to hot plate test, with no significant effect in the hot water tail immersion test when compared with control. Naloxone significantly (p < 0.05) reversed the effect of EETC on hot plate-induced pain. In conclusion, the results of this study provide evidence, showing that EETC possesses phytochemical compounds with analgesic activity and may be related to peripheral nociception mediation and central opioidergic pain pathway system. Keywords: Triumfetta cordifolia; Analgesia; Writhing; Paw-licking