Further studies on the anti-nociceptive and anti-inflammatory effects of the aerial parts of Hilleria latifolia (Lam.) H. Walt.

Abstract

The aerial parts of Hilleria latifolia are used in Ghanaian traditional medicine for the treatment of pain and inflammatory disorders. In the current study, the anti-nociceptive and anti-inflammatory effects of the hydro-ethanol (HAE), ethyl acetate (EAE) and petroleum ether (PEE) extracts of the aerial parts of the plant were investigated in animal models. The analgesic effects were assessed in the acetic acidinduced writhing and formalin tests while the anti-inflammatory activities were tested in the carrageenan-induced oedema model in chicks. HAE (10-100 mg kg-1, p.o.), EAE (10-100 mg kg-1, p.o.), PEE (10-100 mg kg-1, p.o.), together with morphine (1-10 mg kg-1, p.o.) and diclofenac (10-100 mg kg-1, p.o.) (positive controls), showed significant anti-nociceptive activity in all the models used. The anti-nociceptive effect exhibited by HAE (30 mg kg-1, p.o.) and PEE (100 mg kg-1, p.o.) were significantly inhibited in the formalin test by the systemic administration of theophylline (10 mg kg-1, i.p). HAE (10-100 mg kg-1, p.o.), given pre-emptively or curatively, significantly inhibited carrageenaninduced foot oedema in 7-day old chicks. PEE (10-100 mg kg-1, p.o.) also significantly attenuated oedema in chicks on curative treatment. In conclusion, the results indicate that HAE, EAE and PEE produce dose-related analgesic effects in mice. The mechanism of action of HAE and PEE involve an interaction with the adenosinergic system. Also, HAE and PEE have significant anti-inflammatory properties after oral administration in animals.