Linalool in essential Plant oils: Pharmacological effects

(-)-Linalool is a monoterpene compound, the natural occurring enantiomer in essential oils. Many reports about the racemate form of this monoterpene and its effect on the brain neurotransmitters, glutamic acid, GABA, acetylcholine and dopamine have been reported. Moreover to linalool has been ascribed a local anaesthetic activity, related to its effects on the nicotinic receptor-ion channel and an activity against several bacteria and fungi. A spasmolityc effect of linalool was also reported as well as antioxidant properties. Studies recently performed by our research group showed that the(-)-linalool possesses anti-inflammatory, antinociceptive and antihyperalgesic effects in different animal models. These properties of (-)-linalool have been ascribed to its capacity in stimulating the opioidergic, cholinergic M2 and dopaminergic D2 systems, as well as to its interaction with K+ channels. In addition, the molecular mechanisms of (-)-linalool on pain responses are, at least partially, mediated by the activity of adenosine A1 and A2A receptors and by reduction of NO production/release, probably through mechanisms where opioidergic, cholinergic and/or glutamatergic systems are involved. Even though many papers have dealt with linalool and (-)-linalool biological actions, its molecular mechanism still remain unknown. (-)-Linalool is a drug that is at least partially effective at ameliorating pain target with a wide range of neurotransmitter systems. Receptors modulated by this compound are often expressed in both the peripheral and central nervous system. Pain research is currently targeting a complex system of receptors, ion channels and their modulators in an effort to identify newer, safer methods of alleviating pain. Thus, (-)-linalool may constitute a valuable tool for the treatment of pain, hyperalgesia and inflammatory pain. Moreover the unique properties of (-)-linalool, which displays antimicrobial, anti-inflammatory, analgesic and antihyperalgesic activity, suggest its possible use in the treatment of infective conditions which are often accompanied by inflammation and pain.