Evaluation of Anti-Inflammatory and Anti-Nociceptive Effects of Defatted Fruit Extract of Olea europaea

Fruits of Olea europaea L. have been used for centuries in folk medicine to treat many inflammatory diseases. In order to evaluate the anti-nociceptive activities of the methanolic and aqueous extracts of defatted fruits of O. europaea, formalin test was used and for evaluation of anti-inflammatory effects of the extract, the volume of paw edema was measured. The results revealed that both extracts did not exhibit significant analgesic activity in the first phase of formalin test, whereas methanolic extract at the 600 mg/kg dose and aqueous extract at the 450 and 600 mg/kg doses could inhibit induced pain in the second phase of formalin test. Furthermore, the results of paw edema volume measurement indicated that the aqueous extract has anti-inflammatory effects at dose of 600 mg/kg. Induced anti-nociception by aqueous olive extract was not reversed by naloxone, which indicates that the opioid receptors are not involved in the analgesic effects of the extracts. The present data pointed out that the extracts of olive defatted fruit have anti-nociceptive and anti-inflammatory effects in rats but further studies are needed to elucidate the mechanism(s) of action and active components which are involved in analgesic and anti-inflammatory effects.