From Science Daily:
Religious leaders have contended for millennia that burning incense is good for the soul. Now, biologists have learned that it is good for our brains too. An international team of scientists, including researchers from Johns Hopkins University and the Hebrew University in Jerusalem, describe how burning frankincense (resin from the Boswellia plant) activates poorly understood ion channels in the brain to alleviate anxiety or depression. This suggests that an entirely new class of depression and anxiety drugs might be right under our noses.
"In spite of information stemming from ancient texts, constituents of Bosweilla had not been investigated for psychoactivity," said Raphael Mechoulam, one of the research study's co-authors. "We found that incensole acetate, a Boswellia resin constituent, when tested in mice lowers anxiety and causes antidepressive-like behavior. Apparently, most present day worshipers assume that incense burning has only a symbolic meaning."
To determine incense's psychoactive effects, the researchers administered incensole acetate to mice. They found that the compound significantly affected areas in brain areas known to be involved in emotions as well as in nerve circuits that are affected by current anxiety and depression drugs. Specifically, incensole acetate activated a protein called TRPV3, which is present in mammalian brains and also known to play a role in the perception of warmth of the skin. When mice bred without this protein were exposed to incensole acetate, the compound had no effect on their brains.