The negative effect of soy extract on erythrocyte membrane fluidity: an electron paramagnetic resonance study.
A decrease of erythrocyte membrane fluidity can contribute to the pathophysiology of hypertension. Soy products, which are used as alternative therapeutics in some cardiovascular conditions, contain various isoflavones (genistein, daidzein, and their glucosides, genistin and daidzin), which can incorporate cellular membrane and change its fluidity. The aim of this study was to examine the effects of soy extract (which generally corresponds to the soy products of isoflavone composition) on erythrocyte membrane fluidity at graded depths. We used electron paramagnetic resonance spectroscopy and fatty acid spin probes (5-DS and 12-DS), the spectra of which are dependent on membrane fluidity. After being treated with soy extract, erythrocytes showed a significant (P = 0.016) decrease of membrane fluidity near the hydrophilic surface, while there were no significant changes of fluidity in deeper hydrophobic membrane regions. These results suggest that soy products containing high levels of genistein and isoflavone glucosides may not be suitable for use in hypertension because they decrease erythrocyte membrane fluidity.
Department of Cytology, Institute for Biological Research Siniša Stanković, University of Belgrade, Despot Stefan Blvd. 142, 11060 Belgrade, Serbia. avlada@ibiss.bg.ac.rs
Vladimir
V
Ajdžanović
Ivan
I
Spasojević
Branka
B
Sošić-Jurjević
Branko
B
Filipović
Svetlana
S
Trifunović
Milka
M
Sekulić
Verica
V
Milošević
D000328:Adult; D002478:Cells, Cultured; D004578:Electron Spin Resonance Spectroscopy; D004910:Erythrocyte Membrane / Q000187:drug effects*; D019833:Genistein / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D007529:Isoflavones / Q000737:chemistry / Q000494:pharmacology; D008560:Membrane Fluidity / Q000187:drug effects*; D013025:Glycine max / Q000737:chemistry*
D007529:Isoflavones; C040641:genistin; C004742:daidzein; D019833:Genistein