Effect of Butylated Hydroxyanisole and Some of Its Derivatives on Human Neutrophil Oxidative Burst: Chemiluminescence Evaluation

Abstract

An acute inflammatory response begins during the reperfusion phase following an ischemic insult in which polymorphonuclear neutrophils (PMNs) play an important role and the release of reactive oxygen species (ROS) causes further damage and a reduction in endogenous antioxidant storage. The ability of butylated hydroxyanisole (BHA) and some phenolic, aliphatic and aromatic BHA derivatives to reduce the human PMN oxidative burst evoked by particulate (Candida albicans and zymosan) or soluble stimulants [N-formyl-methionyl-leucyl-phenylalanine (fMLP) and phorbol myristate acetate (PMA)] was investigated using luminol-amplified chemiluminescence. BHA and the derivative dt-BHA [3,5-di-t-butyl-4-hydroxyanisole] significantly reduced the PMN oxidative burst at concentrations ranging from 5 × 10^–6 to 5 × 10^–5 mol/l for C. albicans stimulation, while for zymosan stimulation, reduction was seen at concentrations ranging from 5 × 10^–6 to 5 × 10^–5 mol/l for BHA, and at concentrations ranging from 5 × 10^–7 to 5 × 10^–5 mol/l for dt-BHA, with dt-BHA being the most active. Another BHA derivative, Bu GAM 1, was active at 5 × 10^–5 mol/l for C. albicans and at 5 × 10^–6 to 5 × 10^–5 mol/l for zymosan. The findings obtained with fMLP and PMA were very similar to those previously reported. ROS release is related to PMN killing activity, but the inhibition of the PMN oxidative burst induced by BHA and BHA derivatives did not significantly modify PMN phagocytosis or killing. It has recently been observed that dt-BHA has a spasmolytic action by inhibiting the influx of Ca²⁺ into cells through L-type Ca²⁺ channels, which means that a single molecule is capable of counteracting two major steps in the sequence of events triggered by ischemia-reperfusion injury, i.e. free radical release and Ca²⁺ overload.