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paintings by Arthur Rackham

Myrcene, or β-myrcene, is an olefinic natural organic compound. It is classified as a hydrocarbon, more precisely as a monoterpene.

Terpenes are dimers of isoprene, and myrcene is one of the most important.  It is a component of the essential oil of several plants including

• bay,
• cannabis,
• ylang-ylang,
• wild thyme,
• parsley, and
• hops.

Terpenes arise naturally from dehydration of terpenol geraniol. It could in principle be extracted from any number of plants, for example wild thyme, the leaves of which contain up to 40% by weight of myrcene. The current route to commercial samples is by the pyrolysis (400 °C) of β-pinene, which is obtained from turpentine.

Myrcene is an important intermediate used in the perfumery industry. It has a pleasant odor, but is rarely used directly. It is also unstable in air, tending to polymerize.

 

Myrcene has an analgesic effect and is likely to be responsible for the medicinal properties of lemon grass tea.

It also has antiinflammatory properties through Prostaglandin E2.

The analgesic action can be blocked by naloxone or yohimbine in mice which suggests mediation by "alpha 2-adrenoceptor stimulated release of endogenous opioids".

Very high doses of myrcene potentiate barbiturate induced sleep in mice, further supporting the suggestions of sedative activity. It is likely that this is responsible for the use of hops and lemongrass as sedatives.