Isoflavones function

The NMR spectra of the product do not show these features. The highest C shift value is Sc = 160.9 and indicates a conjugated carboxy-C atom instead of the keto carbonyl function of an isoflavone (5c =175). On the other hand, a deshielded CH fragment at 5c/<5 = 138.7/7.i52 appears in the C NMR spectrum, which belongs to a CC double bond polarised by a -A/effect. The two together point to a coumarin 4 with the substitution pattern defined by the reagents. 

The effects of phytoestrogens on cognitive function have also been investigated in humans. However, the results of these studies were inconclusive. White et al, (2000) concluded that tofu consumption in midlife was associated with diminished cognitive function later in life. In contrast. File et al. (2001) reported that short-term consumption of high levels of isoflavones (100 mg/day) may improve memory. 

MESSINA M, GUGGER E T and ALEKEL D L (2001) Soy protein, soybean isoflavones, and bone health a review of the animal and human data. In Wildman REC, Handbook of Nutraceuticals and Functional Foods, Boca Raton, CRC Press EEC, 77-98. 

Functionalized isoflavones can be easily obtained from the cross-coupling reaction of 3-iodochromones with Ar3Bi under Pd catalysis (Scheme 44). The coupling reaction of a variety of substituted 3-iodochromones and Ar3Bi afforded substituted isoflavones in high yields [60]. 

It is noteworthy that a cross-sectional study in 301 postmenopausal women (60 to 75 years of age) in the Netherlands, where isoflavone and lignan intakes were assessed with a food frequency questionnaire covering habitual diet during the year prior to the study, reported no associations between isoflavone intake and vascular function, including endothelial function, blood pressure, and hypertension, and this is in contrast to the observed protective effect of dietary lignan intake on blood pressure and hypertension. 

Consumption of soy foods for 10 weeks (100 mg/day isoflavones) has been reported to improve human memory in young healthy adults and consumption of a soy isoflavone supplement for 12 weeks (60 mg/day isoflavones) to improve cognitive function in postmenopausal women. By contrast, consumption of soy protein (99mg isoflavones/day) for 12... 

Although toxicity from isoflavones may arise from their action as alternative substrates for the enzyme thyroid peroxidase and people in southeast Asia would be protected by the dietary inclusion of iodine-rich seaweed products, a recent study has shown that isoflavone supplements do not affect thyroid function in iodine-replete postmenopausal women. Considerations of the safety of soy isoflavones is an area of great interest in relation to their potential benefits to human health and has recently been comprehensively reviewed. ... 

Steinberg FM, Guthrie NL, Villablanca AC, Kumar K, Murray MJ. Soy protein with isoflavones has favourable effects on endothelia function that are independent of lipid and antioxidant effect in health postmenopausal women. Am. J. Clin. Nutr. 78, 123-130, 2003. 

Duffy R, Wiseman H, File S. Improved cognitive function in postmenopausal women after 12 weeks of consumption of a soy extract containing isoflavones. Pharmacol. Biochem. Behav. 75, 721-729, 2003. 

Kreijkamp-Kaspers S, Kok L, Grobbee DE et al. Effect of soy protein containing isoflavones on cognitive function, bone mineral density and plasma lipids in postmenopausal women. J. Am. Med. Assoc. 292, 65-74, 2004. 

Bruce B, Messina M, Spiller GA. Isoflavone supplements do not affect thyroid function in iodine replete postmenopausal women. J. Med. Food 6, 309-316, 2003. 

Dipole moments of flavone (22) and isoflavone (64) have been calculated as a function of the angle by which the phenyl ring is rotated out of the plane of the chromone moiety (B-77MI22200). Correlation of the observed and calculated moments occurs when the ring is turned through less than 30° in the case of flavone, but through approximately 50° for the other flavonoid, and it thus appears that neither molecule is planar. 

Table 10.3 Molar Extinction Coefficients (a) of Isoflavones as a Function of Wavelength and Solvent ...

Hendrich S, Murphy SP. Isoflavones Sources and Metabolism. In Wildman REC, editor. Handbook of neutraceuticals and functional foods. Boca Raton CRC Press, 2001. p. 55-72. 

Genovese MI, Barbosa AC, Pinto Mda S, Lajolo FM. 2007. Commercial soy protein ingredients as isoflavone sources for functional foods. Plant Foods Hum Nutr 62 53-58. 

Mahn K, Borras C, Knock GA, Taylor P, Khan IY, Sugden D, Poston L, Ward JP, Sharpe RM, Vina J, Aaronson PI, Mann GE. 2005. Dietary soy isoflavone induced increases in antioxidant and eNOS gene expression lead to improved endothelial function and reduced blood pressure in vivo. Faseb J 19 1755-1757. 

Turner NJ, Thomson BM, Shaw IC. 2003. Bioactive isoflavones in functional foods The importance of gut microflora on bioavailability. Nutr Rev 61 204-213. 

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