ANTINOCICEPTIVE EFFECT OF 4-ALLYL-2-METHOXYPHENOL AND DICLOFENAC CO-ADMINISTRATION IN THE FORMALIN TEST IN RATS

Pain is one of the main ailments that affects humanity. To treat it, non-steroid anti-inflammatory analgesics have been widely used and also opioid analgesics, but to a lesser extent. The use of natural extracts has provided excellent results and represents a new treatment alternative. This study aimed to evaluate the antinociceptive effect of the co-administration of 4-allyl-2-methoxyphenol (eugenol; clove essential oil, Syzygium aromaticum) and diclofenac through the formalin test. Eugenol-diclofenac combinations were used at total doses of 725 mu g/kg b.w. and 962.5 mu g/kg b.w. to measure the antinociception through the formalin test in Wistar Kyoto rats. The combination eugenol-diclofenac in a dose of 962.5 mu g/kg b.w. showed the highest effect in the behavioural nociceptive inhibition compared to the combination of 725 mu g/kg b.w. and individual treatments (eugenol 1200 mu g/kg b.w. and diclofenac 250 mu g/kg b.w.). In this context, it was obtained a 92.29 +/- 0.64% of antinociception in phase 1 accentuated up to 94.84 +/- 0.79% in phase 2. The eugenol and diclofenac combination in the dose of 962.5 mu g/kg b.w. showed a supra additive antinociceptive effect, higher than the dose of 725 mu g/kg b.w. and the individual doses, which suggests a combination of the antinociceptive mechanisms of eugenol and diclofenac.