Tetradecylthioacetic acid and tetradecylselenoacetic acid inhibit lipid peroxidation and interact with superoxide radical

Reactive oxygen species are thought to induce cellular damage and to play a pathological role in several human diseases. Tetradecylthioacetic acid (TT A) was previously reported to prevent the oxidative modification of low-den sity lipoprotein (LDL) particles and to act as an antioxidant. In this stud y we present a new fatty acid analogue, namely tetradecylselenoacetic acid (TSA), in which the sulfur atom of TTA is replaced by a selenium atom. TSA was more potent than TTA in increasing the lag time before the onset of LDL oxidation and this effect was dose dependent. TTA and TSA were shown to re duce the iron-ascorbate-induced microsomal lipid peroxidation, TSA being mo re efficient than TTA. TTA and TSA, in the presence of iron, interacted wit h the superoxide radical as assessed by direct and indirect testing methods . TSA like TTA failed to scavenge 1.1-diphenyl-2-picrylhydrazyl radicals. T SA bound copper ions as shown by the wavelength spectra measurement. These results suggest that TTA and TSA exert their antioxidant capacity by intera ction with copper or iron ions in radical scavenging, TSA being more potent than TTA. Nevertheless, a chelating effect resulting in chemically inactiv e metal ions cannot be excluded. (C) 2000 Elsevier Science Inc.