Analgesic and Anti-inflammatory Activities of the Ethylacetate Extract of Mitracarpus villosus Leaves in Rodents

Aims: To investigate the effects of the ethylacetate extract of Mitracarpus villosus leaves using various in-vivo models of pain, inflammation and pyrexia.

Study Design: This study was designed to investigate the possible analgesic, anti-inflammatory and anti-pyretic effects of ethylacetate extract of Mitracarpus villosus leaves in rodents.

Place and Duration of Study: Department of Pharmacology and Toxicology, National Institute for Pharmaceutical Research and Development, Idu Industrial Area, Abuja, Nigeria; between September 2013 and February 2014.

Methodology: The effects of the extract on centrally and peripherally mediated pain were investigated in albino mice and Wistar rats. The anti-nociceptive effects of the extract were tested on acetic acid-induced abdominal writhing, oro-facial formalin-induced pain in mice and carageenaan–induced hyperalgesia in rats. The effects of the extract on inflammation and body temperature were determined using formalin induced paw oedema and Baker’s yeast induced pyrexia respectively.

Results: The extract at 100 – 400 mg/kg significantly (P ≤ 0.05) and dose-dependently inhibited acetic acid-induced abdominal writhing, decreased the time of face rubbing induced by formalin and increased the withdrawal threshold of rat paws injected with carageenaan to induced hyperalgesia. At 400 mg/kg, paw thickness induced by formalin was significantly reduced when compared to control. The analgesic and anti-inflammatory effects of the extract are comparable to pentazocine and diclofenac. Hyperthermia induced by Baker’s yeast was significantly reversed by the extract in a manner similar to paracetamol.

Conclusion: The results obtained suggest that the ethylacetate extract of Mitracarpus villosus leaves may contain biologically active principles with potential analgesic, anti-inflammatory and anti-pyretic effects; thus supporting its use as a phytomedicine and buttressing the need for the isolation and identification of the biologically active constituent(s) of this plant.