July 22, 2008 — Cannabis has long been accredited with anti-inflammatory properties. ETH Zurich researchers, however, have now discovered that it is not only the familiar psychoactive substances that are responsible for this; a compound we take in every day in vegetable nutriment also plays a significant role.


People not only rate cannabis sativa L. highly because of its intoxicating effects; it has also long been used as a medicinal plant. Although the plant has been scrutinized for years, surprising new aspects keep cropping up. For example, researchers from ETH Zurich and Bonn University examined a component in the plant’s essential oil that until then had largely been ignored and found it to have remarkable pharmacological effects. The findings open up interesting perspectives, especially for the prevention and treatment of inflammation.

Completely different molecule structure

The hemp plant contains over 450 different substances, only three of which are responsible for its intoxicating effect. They activate the two receptors in the body CB1 and CB2. Whilst the CB1 receptor in the central nervous system influences perception, the CB2 receptor in the tissue plays a crucial role in inhibiting inflammation. If the receptor is activated, the cell releases fewer pro-inflammatory signal substances, or cytokines. The scientists have now discovered that the substance beta-carophyllene, which composes between 12 and 35 percent of the cannabis plant’s essential oil, activates the CB2 receptor selectively.

Unlike the three psychoactive substances, however, beta-carophyllene does not latch onto the CB1 receptor and consequently does not trigger the intoxicating effect. “Due to the various effects of cannabis, we had suspected for quite some time that other substances could come into play besides the psychoactive ones”, explains Jürg Gertsch from the Institute of Pharmaceutical Sciences at ETH Zurich. “However, astonishingly we didn’t know what substances these were until now.”

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