Antioxidant Activity of Bisabolol: Inhibitory Effects on Chemiluminescence of Human Neutrophil Bursts and Cell-Free Systems

Human polymorphonuclear neutrophils (PMN), reactive oxygen species (ROS) and inflammatory reactions are closely interrelated, and increasing attention is being given to the search for new synthetic or natural antioxidant agents, capable of reducing ROS and consequent inflammation. It has been claimed that bisabolol (a monocyclic sesquiterpene alcohol) has an antioxidant/anti-inflammatory activity, but this has almost exclusively been investigated using chemical or biochemical tests. We studied the ability of bisabolol to interfere with ROS production (luminol-amplified chemiluminescence, LACL) during human PMN respiratory bursts induced by both corpusculate<i>(Candida </i><i>albicans)</i>and soluble stimulants (N-formyl-methionyl-leucyl-phenylalanine, fMLP). LACL was also used to test cell-free systems (SIN-1 and H₂O₂/HOCl^– systems) in order to investigate the presence of scavenging activity. After <i>C. albicans</i> stimulation, significant concentration-dependent LACL inhibition was observed at bisabolol concentrations ranging from 7.7 to 31 μg/ml; after the fMLP stimulus, significant LACL inhibition was observed at bisabolol concentrations ranging from 3.8 to 31 μg/ml. A similar effect was observed in the SIN-1 and H₂O₂/HOCl^– systems. These findings draw the attention to the possible medical use of bisabolol as a means of improving the antioxidant network and restoring the redox balance by antagonising oxidative stress.