Antinociceptive activity of Amazonian Copaiba oils.

Copaiba oil resins are extensively commercialized in Brazil as capsules or crude oil and used as anti-inflammatory and anti-septic. Comparative pharmacological studies between different species of Copaiba oils are scarce. In the present work we compared the antinociceptive activity of two Amazonian Copaiba oils (Copaifera multijuga Hayne and Copaifera reticulata Ducke, Fabaceae) administered by oral route using peripheral (acetic acid-induced abdominal writhing and formalin), spinal (tail flick) and supra-spinal (hot plate) models. Results demonstrated that the Copaiba oils did not develop toxic effects. Doses ranging from 30 to 150 mg/kg were enough to significantly develop peripheral antinociceptive effect. All Copaiba oils demonstrate central activity but with less effect on supra-spinal regions of the brain. Administration of the opioid receptor antagonist, naloxone completely inhibited the antinociceptive effect induced by both Copaiba oils. Our results indicate that Copaiba oils demonstrate peripheral and central antinociceptive effect. This new comprobate effect may be useful in the treatment of algesic disorders.