Effect of circulating forms of soy isoflavones on the oxidation of low density lipoprotein |
| |
Authors: | Turner Rufus Baron Tobias Wolffram Siegfried Minihane Anne Marie Cassidy Aedin Rimbach Gerald Weinberg Peter D |
| |
Affiliation: | a School of Food Biosciences, Hugh Sinclair Human Nutrition Unit, University of Reading, Reading, UKb Physiology and Metabolism, Institute of Animal Nutrition, Christian-Albrechts-University Kiel, Kiel, Germanyc School of Animal and Microbial Sciences, University of Reading, Reading, UK |
| |
Abstract: | Soy isoflavones are thought to have a cardioprotective effect that is partly mediated by an inhibitory influence on the oxidation of low density lipoprotein (LDL). However, the aglycone forms investigated in many previous studies do not circulate in appreciable quantities because they are metabolised in the gut and liver. We investigated effects of various isoflavone metabolites, including for the first time the sulphated conjugates formed in the liver and the mucosa of the small intestine, on copper-induced LDL oxidation. The parent aglycones inhibited oxidation, although only 5% as well as quercetin. Metabolism increased or decreased their effectiveness. Equol inhibited 2.65-fold better than its parent compound daidzein and 8-hydroxydaidzein, not previously assessed, was 12.5-fold better than daidzein. However, monosulphated conjugates of genistein, daidzein and equol were much less effective and disulphates completely ineffective. Since almost all isoflavones circulate as conjugates, these data suggest that despite the increased potency produced by some metabolic changes, isoflavones may not be effective antioxidants in vivo unless they are deconjugated again. |
| |
Keywords: | Soy Isoflavones Antioxidant Low density lipoprotein Equol 8-Hydroxydaidzein |
本文献已被 InformaWorld PubMed 等数据库收录! |
|