Anti-nociceptive and anti-inflammatory activities of (-)-α-bisabolol in rodents

(-)-alpha-Bisabolol is an unsaturated, optically active sesquiterpene alcohol obtained by the direct distillation of essential oil from plants such as Vanillosmopsis erythropappa and Matricaria chamomilla. (-)-alpha-Bisabolol has generated considerable economic interest, as it possesses a delicate floral odour and has been shown to have antiseptic and gastroprotective activities. In this study, (-)-alpha-bisabolol was tested in standardised rodent models by gavage administration at doses of 100 and 200 mg/kg in the models of inflammation and 25 and 50 mg/kg in the models of nociception. In the inflammatory models of paw oedema induced by carrageenan and dextran, the mice treated with (-)-alpha-bisabolol showed smaller oedemas compared to animals treated only with the vehicle. (-)-alpha-Bisabolol was capable of reducing paw oedemas induced by 5-HT but not oedemas induced by histamine. (-)-alpha-Bisabolol demonstrated anti-nociceptive activity in the models of visceral nociception induced by acetic acid and in the second phase of the nociception test induced by the intraplantar administration of formalin. (-)-alpha-Bisabolol did not have any effect in a thermal nociception model using a hot plate but was able to diminish mechanical inflammatory hypernociception evoked by carrageenan. These findings suggest that the anti-nociceptive action of (-)-alpha-bisabolol is not linked to a central mechanism but instead is related to the inflammatory process. (-)-alpha-Bisabolol was able to decrease leukocyte migration, protein extravasations and the amount of TNF-alpha to the peritoneal cavity in response to carrageenan. Additionally, (-)-alpha-bisabolol reduced neutrophil degranulation in response to phorbol-myristate-acetate. We demonstrate, for the first time, the peripheral anti-inflammatory and anti-nociceptive activities of (-)-alpha-bisabolol.