Isoflavonoid glucosides

Before 1990 the composition of isoflavones in soy foods was thought to be largely determined by whether the food had been fermented. Fermented foods (e.g., miso and tempeh) contain the unconjugated isoflavones agycones, while non-fermented food (e.g., tofu, soy flower, and soy milk) contain the conjugated glucoside. Subsequent experiments have demonstrated that fermentation of soy decreased the isoflavone content of the food product, but increased the urinary isoflavonoid recovery, suggesting that fermentation increases availability of isoflavones in soy (Slavin et al., 1998). 

FIGURE 7.2 Chemical structures of the main soy (genistein and daidzein) and red clover (biochanin A and formononetin) isoflavonoids (aglycones and glucosides). 

Birt, D.F., Hendrich, S., and Wang, W. 2001. Dietary agents in cancer prevention Flavonoids and isoflavonoids. Pharmacol. Ther. 90.157-177. Coward, L., Baines, N.C., Setchell, K.D.R., and Barnes, S. 1993. Genistein, daidzein, and their P-glucoside conjugates Antitumor isoflavones in soybean foods from American and Asian diets. 

A similar pattern of isoflavonoids and their glycosides is observed in alfalfa where formon-etin 7-0-/3-glucoside-6"-0-malonate (6) accumulates in roots along with other isoflavonoid constituents [11]. 

Daidzein (7,4 -dihydroxyisoflavone) (28) and pratensein (5,7,3 -trihydroxy-4 -methoxyisoflavone) (29) were identified in seedlings of C. arietinum along with biochanin A 7-O-glucoside (sissotrin) (30) the first report of an isoflavonoid glycosides in Cicer [23], Subsequently... 

Plants are the best organic chemists in nature as evidenced by their ability to synthesize all necessary carbon compounds with carbon dioxide as the sole carbon source and by their ability to synthesize a vast number of natural products. Currently, structures for more than 100,000 different natural products isolated from plants are known, and with time this number will increase into millions. Natural products are classified as phytoanticipins, phytoalexins, and/or attractants. In the last decade, the majority of the biosynthetic pathways responsible for natural product synthesis have been shown to include P450s as key enzymes. Such pathways include the biosynthetic pathways for cyanogenic glucosides, glucosinolates, isoflavonoids, and... 

Observations with the isoflavonoid genistin (genistein-7-glucoside) support our findings with QG. As for QG, this glucoside was not absorbed by the Caco-2... 

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