Inhibition of lipid peroxidation in isolated rat liver mitochondria by the general anaesthetic propofol.

The effect of the general anaesthetic propofol (2,6-diisopropylphenol) on lipid peroxidation in rat liver mitochondria was assessed with the thiobarbituric acid (TBA) assay. Propofol was shown to inhibit the accumulation of TBA-reactive compounds after initiation of radical production by the addition of the ADP-Fe2+ complex. Analysis of kinetics showed that propofol caused a concentration-dependent delay as well as a decrease in the rate of the peroxidation process. 1H-NMR spectra of mitochondrial lipid extracts indicated that 95% of the added propofol remained intact after 30 min incubation under conditions of low oxidative stress. The ESR spectrum of propofol incubated in the presence of EDTA-Fe2+ and H2O2 as initiators of radical production showed a radical that was most likely a decomposition product of the primary phenoxy radical of propofol. It is concluded that (a) propofol acts as a chain reaction-breaking antioxidant by forming a stable radical and (b) propofol does not seem to be metabolized in mitochondria in vitro.