Copaifera officinalis L. possesses traditional uses as an analgesic, anti-inflammatory, and antiseptic. However, until now the antinociceptive effect and the mechanism of action were not described for Copaifera officinalis L. oil and no compound present in this oil was identified to be responsible for its biological effects. The goal of this study was to identify the presence of kaurenoic acid in Copaifera officinalis oil and investigate its antinociceptive effect, mechanism of action, and possible adverse effects in mice. The quantification of kaurenoic acid in Copaifera officinalis oil was done by HPLC-DAD technique. Male and female albino Swiss mice (25-35 g) were used to test the antinociceptive effect of Copaifera officinalis (10 mg/kg, intragastric) or kaurenoic acid (1 mg/kg) in the tail-flick test, intraplantar injection of capsaicin, allyl isothiocyanate (AITC) or complete Freund's adjuvant (CFA). Copaifera officinalis oil and kaurenoic acid caused the antinociceptive effect in the tail-flick test in a dose-dependent manner, and their effect was reversed by naloxone (an opioid antagonist). Copaifera officinalis oil or kaurenoic acid reduced the nociception caused by capsaicin or AITC and produced an anti-allodynic effect in the CFA model (after acute or repeated administration for 7 days). Possible adverse effects were also observed, and non-detectable adverse effect was observed for the intragastric administration of Copaiba officinalis oil or kaurenoic acid and in the same way, the treatments were neither genotoxic nor mutagenic at the doses tested. Thus, Copaiba officinalis oil, and kaurenoic acid possess antinociceptive action without adverse effects.
Keywords: Capsaicin; Copaiba oil; Inflammatory pain; Morphine; Naloxone; Nociception.