Background: TNBS-induced colitis is an experimental immunopathology in rats that shares
many features with human inflammatory bowel diseases. Copaiba oleoresin is extracted from plants of
the genus Copaifera and is shown to reduce inflammation.
Objective: The aim of this study was to investigate the action of copaiba oil (C. reticulata Ducke) on
inflammation and oxidative status in the distal colon of colitic rats.
Methods: Acute and subchronic colitis were induced in Wistar rats by an intracolonic enema with
2,4,6-trinitrobenzenesulfonic acid (TNBS). The colonic morphology was assessed by histological
analysis and the oxidative stress parameters were measured in the intestinal homogenate. The liver
damage markers were measured in the plasma. Control and colitic rats were orally treated either with
one single dose (acute colitis) of copaiba oil (1.15 g Kg-1) or once a day during seven days (subchronic
Results: The intestinal morphology was severely modified by acute and subchronic colitis, as indicated
by the intramural infiltration of polymorphonuclear cells and the increased thickness of all colon layers.
The levels of TBARS, protein carbonyl groups and reactive oxygen species (ROS) were increased
in the intestine of colitic rats. Copaiba oil did not attenuate the inflammatory damage in acute and subchronic
colitis, but it decreased the activity of myeloperoxidase, leukocyte infiltration and oxidative
stress in the colon. The level of plasma bilirubin and the activity of alkaline phosphatase were both
increased in treated healthy and colitic rats.
Conclusion: Copaiba oil decreased oxidative stress and inflammation but did not prevent intestinal
damage in the colon of colitic rats. The alterations of plasma markers of hepatic damage caused by the
oil seem to be associated to its harmful action on the liver.