Evaluation of the Sesquiterpene (-)-alpha-Bisabolol as a Novel Peripheral Nervou

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Neurosci Lett. 2010 Jan 24.

Evaluation of the Sesquiterpene (-)-alpha-Bisabolol as a Novel Peripheral

Nervous Blocker.

Alves AD, Gonçalves JC, Cruz JS, Araújo DA.

Laboratório de Tecnologia Farmacêutica, Universidade Federal da Paraíba, João

Pessoa, PB, Brasil.

Essential oils are natural, complex and multi-component systems composed mainly

of terpenes in addition to some other non-terpenes compounds that are widely

used to prevent and treat human diseases. (-)-alpha-Bisabolol is an unsaturated

monocyclic sesquiterpene alcohol found as the major constituent of many

essential oils, like the German chamomile (C. recutita (L.) Rauschert), a plant

reported to reduce the perception of acute pain and used for centuries for their

medicinal properties.

Recently, our group demonstrated the antinociceptive-like effect promoted by

other terpenes could be associated with the decreased peripheral nerve

excitability. Therefore, this study investigated the pharmacological activities

of (-)-alpha-bisabolol on mice peripheral nervous system observing the changes

on the compound action potential (CAP) characteristics.

Using modified single sucrose-gap method in mice sciatic nerves, we acquired CAP

recordings in the absence and presence of (-)-alpha-bisabolol (0.5, 1, 5 and

10mM). We observed that this sesquiterpene was able to reduce the neuronal

excitability in a concentration-dependent manner, although, such effects were

not reversed when the nerve was submitted to wash out. Assessing CAP parameters

of depolarization and repolarization, we noticed similarities between

(-)-alpha-bisabolol and lidocaine but not with 4-aminopyridine that are

considered good blockers for sodium and potassium voltage-gated channels,

respectively.

Additionally, we also characterized the non use-dependent profile of

(-)-alpha-bisabolol action, in contrast to lidocaine. Thus, we suggested that

decreased nervous excitability elicited by (-)-alpha-bisabolol might be caused

by an irreversible blockade of voltage-dependent sodium channels.