Plants, isoflavone analysis

Sato et a2- (34) demonstrated that a variety of common meat additives, inclucnrTg cottonseed flour, nonfat dry milk, spray-dried whey, wheat germ, and textured soy flour, inhibited WOF in the meat system. These products may have exerted their inhibitory effect on WOF through the Maillard reaction, since most of them contain some reducing sugars. Pratt (40) reported soybeans and soy protein concentrate had an inhibitory effect upon development of WOF and was able to demonstrate that the active components are water soluble. Fractionation and analysis of the water-soluble fraction showed the antioxidant activity was due to the presence of isoflavones and hydroxylated cinnamic acids (40). This confirms earlier work showing that the flavonoTcis present in plant extracts inhibit oxidation in sliced roast beef (41 ). 

Table 13. Structures and Plant Sources of Phenolic Compounds (the structure shows in parenthesis as follows isoflavone (3, 5,7-3 x OH, 6-prenyl, Dmp[5, 4 ]) means 2",2"-dimethylpyrano[5",6" 5, 4 ]-6-prenyl-3, 5,7-trihydroxyisoflavone (260) HPLC = detection with HPLC analysis ud = our unpublished data n.r. = not reported callus means cell cultured of Glycyrrhiza species)...

The flavonoids are among the most numerous and widespread natural products found in plants and have many diverse applications and properties. There have been several texts published on flavonoids, some comprising collections of specialist chapters [1-5], and a number of more practically oriented texts have appeared independently [6-11]. A previous edition of this book contains a detailed treatise on the analysis and identification of flavonoids in practice [11]. Rather than simply describe further techniques of flavonoid analysis, we have chosen in this chapter to present two significant examples of the application of techniques previously described. These applications demonstrate how the various available techniques are used in concert to produce pure flavonoids and to establish their structures. Selected for this purpose are two classes of flavonoids that we see as having contemporary emerging importance, the isoflavones and the 3-deoxyanthocyanins. 

Deavouis, B.E. etal. (2006) Functional analysis of members of the isoflavone and isofla-vanone O-methyltransferase enzyme families from the model legume Medicago truncatula. Plant Mol. Biol. 62, 715-733... 

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