Antioxidant properties of anesthetics: the biochemist, the surgeon and the anesthetist.

General anesthesia can impair immunological defense mechanisms while inducing an inflammatory reaction. Generalized inflammatory reactions involve leucocytes which in turn release inflammatory mediators and free oxygen radicals. General anesthetics include a series of gaseous and intravenous sedative-hypnotic agents indicated for induction and maintenance of general anesthesia as well as for sedation of intubated, mechanically ventilated adults in intensive care units (ICU). Some anesthetics, such as propofol, are characterized by a phenolic structure similar to that of alpha-tocopherol, and exhibit antioxidant properties that have been demonstrated both in vitro and in vivo. Similarly, other anesthetics show antioxidant and protective roles but this mechanism is to be related to their ability to induce antioxidant enzyme (i.e., heme oxygenase-1). The aim of the present review is to evaluate the antioxidant properties of anesthetics in various experimental models and if they may be considered efficient therapeutic tools in counteracting oxidative stress during general anesthesia and sedation in ICU.