By Pat Anson, Editor

An essential oil made from the resin of a tree that grows in the Amazon rain forest shows promising results as a treatment for arthritis, but there is no clinical evidence to support its use, according to researchers at Florida Atlantic University.

Copaiba (koh-pey-buh) is an oleoresin obtained from the trunk of several pinnate-leaved leguminous trees. The resin has been used for centuries in folk medicine, and is also used in the manufacture of paint, varnish, perfume and soap. Brazil produces about 95 percent of the world’s supply of copaiba and exports more than 500 tons a year.

Essential oil made from copaiba is increasingly available in health food stores and online, where it is touted as a “wonderful analgesic” and “one of the most anti-inflammatory substances on earth.”

"Copaiba is an essential oil that is used topically with little or no side effects, but there is insufficient evidence to judge whether it reduces pain and inflammation in patients with arthritis," said Charles Hennekens, MD, senior academic advisor at Florida Atlantic’s College of Medicine and senior author of a commentary published in the journal Integrative Medicine.

"In case reports, individuals with joint pain and inflammation who used copaiba reported favorable results, however, this hypothesis is promising but as of yet unproven."

Hennekens and his colleagues say the evidence to support copaiba as a treatment for inflammatory arthritis is limited to basic research and uncontrolled clinical observations in humans. They caution that randomized trials are necessary to discern whether copaiba oil is effective or if it turns out to be "yet another beautiful hypothesis slain by ugly facts."

"Basic research has suggested mechanisms of benefit of this essential oil in treating inflammatory arthritis," said Hennekens. "Nonetheless, the only published data on copaiba on humans includes one case series and one small randomized trial of another inflammatory condition and not arthritis."

The researchers conclude that the totality of the evidence for copaiba is insufficient to judge either its benefits or risks for the relief of arthritis pain and inflammation. Despite this lack of evidence, sales of copaiba oils continue to increase as patients look for alternatives to pharmaceutical pain relievers.

"Copaiba should be first tested in a randomized trial against a placebo in patients with inflammatory arthritis," said Hennekens. "If such a trial shows a net benefit, then the next step would be direct randomized comparisons against NSAIDs and COXIBs (cyclo-oxygenase-2 inhibitors).”