Faculty Collaboration Database

Antioxidant mechanisms of isoflavones in lipid systems: paradoxical effects of peroxyl radical scavenging. Free Radic Biol Med 2001 Dec 15;31(12):1570-81

Date

12/18/2001

Pubmed ID

11744331

DOI

10.1016/s0891-5849(01)00737-7

Scopus ID

2-s2.0-0035893957 (requires institutional sign-in at Scopus site)   161 Citations

Abstract

Oxidation of lipids has been implicated in the pathophysiology of atherosclerosis. It has been suggested that scavenging of lipid peroxyl radicals contribute to the antiatherosclerotic effects of naturally occurring compounds such as the isoflavones. This group of polyphenolics includes genistein and is present in relatively high concentrations in food products containing soy. Soy isoflavones are capable of inhibiting lipoprotein oxidation in vitro and suppressing formation of plasma lipid oxidation products in vivo. However, key aspects of the antioxidant mechanisms remain unknown. In this study the antioxidant effects of genistein and other soy isoflavones on lipid peroxidation initiated by mechanistically diverse oxidants was investigated. Although isoflavones inhibited lipid peroxidation stimulated by both metal-dependent and independent processes, the concentration required for these effects were relatively high compared to those found in vivo. Interestingly, however, isoflavones were not consumed and remained in the native state over the time during which inhibition of lipid peroxidation was observed. This was also the case under conditions where synergistic inhibition of LDL oxidation was observed with ascorbate. Furthermore, in an oxidation system driven solely by peroxyl radicals, isoflavones were found to be relatively poor peroxyl radical scavengers. Consistent with the apparent lack of reactivity with lipid-derived oxidants, isoflavones were also relatively resistant to oxidation mediated by the potent oxidant peroxynitrite. The potential antioxidant mechanisms of isoflavones are discussed in the context of possible reactivities of isoflavone-derived phenoxyl radicals.

Author List

Patel RP, Boersma BJ, Crawford JH, Hogg N, Kirk M, Kalyanaraman B, Parks DA, Barnes S, Darley-Usmar V

Authors

Neil Hogg PhD Associate Dean, Professor in the Biophysics department at Medical College of Wisconsin
Balaraman Kalyanaraman PhD Professor in the Biophysics department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Antioxidants
Ascorbic Acid
Drug Synergism
Free Radical Scavengers
Free Radicals
Genistein
Humans
Lipid Peroxidation
Lipid Peroxides
Lipoproteins, LDL
Liposomes
Models, Biological
Oxidation-Reduction
Peroxides