Phytoestrogens assays

In assay sytems, many of these phytoestrogens are able to bind more avidly to the estrogen receptor than estrogen itself. Why plant products should possess such avid estrogenic compounds is unclear, but it has been suggested that consumption of phytoestrogens by insects may result in alterations in the sex... 

Branham et al. [11] used an ER-ligand binding assay to measure the RBA for 46 chemicals considered to be potential phytoestrogens and mycoestrogens. The classes of chemicals examined (flavones, isoflavones, flavanones, coumarins, chalcones, and mycoestrogens) are shown in Figure 18.8. Representative chemicals from each of these classes showed some affinity for ER, ranging widely in RBAs from 43 to 0.00008 E2 = 100). No further work was done to describe specific SARs for these classes. 

Immunoassay is one of the most sensitive analytical techniques described for phytoestrogen measurements in human biological fluids. Detection limits for target analytes are below 1 nmol/L for most methods with an average recovery of 92% and inter-/intra-assay variation less than 10% for most methods (WiUdnson et al., 2002). Immunoassays have been validated against other analytical techniques and excellent correlation has been demonstrated. Immunoassay can be a powerful alternative to GC-MS- or HPLC-based methods for studying the bioavaUabflity and metabolic fate of dietary isoflavonoids because of its ease, relatively low cost, availability for... 

Garrett, S.D., Lee, H.A., Friar, P.M.K., and Morgan, M.R.A., Vahdation of a novel estrogen receptor-based microtitration plate assay for the determination of phytoestrogens in soy-based foods, J. Agric. Food Chem., 47, 4106-4111, 1999. 

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