Genotoxic activity of four metabolites of the soy isoflavone daidzein.

Abstract

Products containing phytoestrogens are increasingly promoted as the "natural" alternative to estrogen replacement therapy. In the present study, we have used the in vitro micronucleus assay in L5178Y mouse lymphoma cells to investigate the genotoxic potential of the isoflavone daidzein, and of four daidzein metabolites known to be formed in humans. Whereas no induction of micronuclei was observed with daidzein up to the limit of solubility (100 microM), all four daidzein metabolites, i.e. equol (2.3-fold induction at 100 microM), O-desmethylangolensin (6.2-fold induction at 10 microM), 4',6,7-isoflavone (6.7-fold induction at 100 microM) and 3',4',7-isoflavone (8.2-fold induction at 100 microM) induced micronuclei in a concentration-dependent manner. Thus, both reductive and oxidative metabolites of the soy isoflavone daidzein exhibit genotoxic potential in vitro.

• Authors: Elmar Schmitt, Manfred Metzler, Rene Jonas, Wolfgang Dekant, Helga Stopper
• Journal: Mutation research (Mutat Res) Vol. 542 Issue 1-2 Pg. 43-8 (Dec 09 2003) ISSN: 0027-5107 [Print] Netherlands
• PMID: 14644352 (Publication Type: Journal Article)

Chemical References

• Isoflavones
• Mutagens
• daidzein

Topics

• Animals
• Cell Division (drug effects)
• Isoflavones (isolation & purification, metabolism, toxicity)
• Leukemia L5178 (pathology)
• Mice
• Micronuclei, Chromosome-Defective (drug effects)
• Micronucleus Tests
• Microscopy, Fluorescence
• Mutagens (isolation & purification, metabolism, toxicity)
• Soybeans (chemistry)
• Tumor Cells, Cultured