Isoflavones commercially available, 522

Since 1999, when the Food and Drug Administration allowed the first health claim for soy-fortified foods in the USA, there has been a large increase in the sales of food products claiming to contain soy isoflavones. At the same time, over-the-counter supplements have become widely available. However, concerns have been raised about the real health benefits of such supplements in the absence of adequate information about bioavailability, pharmacokinetics and safety. To fill this gap, an extensive study on pure isoflavones and commercial soy isoflavone supplements has recently been carried out (Setchell et al, 2001). A selection of 31 commercially available supplements showed a wide variation in isoflavone composition and in the amount provided by one tablet. Furthermore, a lower isoflavone content, with respect to the claimed levels, has been observed in almost 50% of the analysed products. In one case, no isoflavones at all could be detected (Setchell et al, 2001). 

Finally, some herbicide antidotes are now commercially available [54], and the naturally-occurring isoflavone genistein (8) has been found to act as an antidote against the herbicides, haloxyflop and alloxydim [55]. However, as far as we are aware, no antidotes to benzimidazole-related compounds, or to other types of fungicides, have previously been reported. 

Red clover herb and flower contain approximately 0.17% isoflavones (DerMarderosian and Beutler 2005), with the herb generally containing a higher percent isoflavone content than the flower (Booth et al. 2006). Commercially available red clover products include products with this normal percentage of isoflavones and those modified to contain up to 100% isoflavones. Products with modified concentrations of selected compounds may be expected to have different physiological effects than traditional preparations of the herb. Information on both red clover and red clover derived isoflavones is provided in this entry. 

Furosine, a marker of the Maillard reaction product, is a valuable indicator of food protein quality. It is a marker for thermal treatment in foodstuffs and is directly related to the loss of lysine availability. IPC was employed to determine furosine content in beverages based on soy milk and cow milk supplemented with soy isoflavones [39]. Furosine was also analyzed in 60 commercial breakfast cereals to assess their protein nutritional values. The higher the protein content in the formulation, the higher the furosine levels [40]. A simple IPC technique that uses 1-octanesulfonic acid as the IPR allowed the selective determination of histamine levels in fermented food [41]. 

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