Isoflavones compounds sources

The value of antioxidant protection by way of natural food sources has been pointed out in the literature with considerable frequency. Among the components of soy flour known to have some antioxidant properties are isoflavones and phospholipids. Amino acids and peptides in soybean flour also possess some antioxidant activity. There also may be some antioxidant impact from aromatic amines and sulfhydryl compounds. 

Isoflavones, a special kind of polyphenols, show similar behaviour regarding absorption and metabolism to this family of compounds. Thus, Scalbert et al [12] put forward two primary sources of evidence concerning the absorption of polyphenols first, indirect evidence for their absorption through the gut barrier as can be seen from the increase in the antioxidant capacity of the plasma following the consumption of polyphenol-rich foods, and second, their recovery in urine after the ingestion of given amounts of a particular polyphenol. 

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5, 4 ]-6-prenyl-3, 5,7-trihydroxyisoflavone (260) HPLC = detection with HPLC analysis ud = our unpublished data n.r. = not reported callus means cell cultured of Glycyrrhiza species)...

One of the main reasons for this lack of concretion is the complexity of plant matrices, whose diversified secondary metabolism includes a vast number of different compounds with close structures that can be hard to identify. Some of these families with a well-documented bibliography related to health effects comprise alkaloids, phenolic compounds (including phenolic acids, stilbenes like resveratrol, or flavonoids such as anthocyanins, procyanidins, or isoflavones), terpenoids, carotenoids, sulfur compounds (such as glucosinolates and isothiocyanates), etc. Their presence and amount in the plant source depend on multiple factors including variety, organ of the plant, soil, sun exposure, climate, or even ways of cultivation. 

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