Abstract:
Fruit extracts of Xylopia aethiopica are used traditionally in the management of pain disorders including
rheumatism, headache, colic pain, and neuralgia. Little pharmacological data exists in scientific literature of the
effect of the fruit extract and its major diterpene, xylopic acid, on pain. The present study evaluated the analgesic
properties of the ethanol extract of X. aethiopica (XAE) and xylopic acid (XA), in murine models. Materials and
Methods: XAE and XA were assessed in chemical (acetic acid-induced abdominal writhing and formalin tests),
thermal (Tail-flick and Hargreaves thermal hyperalgesia tests), and mechanical (Randall-Selitto paw pressure test)
pain models. Results: XAE and XA exhibited significant analgesic activity in all the pain models used. XAE (30-300
mg kg-1, p.o.) and XA (10-100 mg kg-1, p.o.) inhibited acetic acid-induced visceral nociception, formalin- induced
paw pain (both neurogenic and inflammatory), thermal pain as well as carrageenan-induced mechanical and
thermal hyperalgesia in animals. Morphine (1-10 mg kg-1, i.p.) and diclofenac (1-10 mg kg-1, i.p.), used as controls,
exhibited similar anti-nociceptive activities. XAE and XA did not induce tolerance to their respective anti-nociceptive
effects in the formalin test after chronic administration. Morphine tolerance did not also cross-generalize to the
analgesic effects of XAE or XA. Conclusions: These findings establish the analgesic properties of the ethanol
fruit extract of X. aethiopica and its major diterpene, xylopic acid.
