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Read this article to learn about Iso-flavone. After reading this article you will learn about: 1. Meaning of Iso-flavone 2. Functions of Iso-flavone 3. Biosynthesis of Iso-flavone 4. Occurrence 5. Research.
Meaning of Iso-Flavone:
Iso-flavones are a class of organic compounds and biomolecules related to the flavonoids. Iso-flavone (3-phenyl-4 H-1 -benzopyr-4-one) differs from flavone in the following: in iso-flavones, the position of the phenyl group on the 4H-1 -benzopyr-4-one skeleton is in position 3 relative to the oxygen of the ring, whereas in flavones it is in position 2.
Iso-flavones are polyphenolic compounds produced almost exclusively by the members of the Fabaceae/Leguminosae (bean) family. Early evidence that plants produced estrogen-like compounds was observed in the infertility among sheep eating large amounts of clover in Australia.
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Similarly, Californian Quails were thought to feed on high-iso-flavone legume seeds during periods of food shortage to reduce their fertility.
Examples of Iso-flavone:
Cenistein, Daidzein, Biochanin A, Formononetin, Coumestrol, Daidzin, Puerarin.
Functions of Iso-Flavone:
i. Act as phytoestrogens in mammals.
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ii. Very strong antioxidants.
iii. Useful in treating cancer.
iv. Significant cholesterol-reducing effects.
v. Have anti-angiogenic effects (blocking formation of new blood vessels).
vi. Plants use iso-flavones and their derivatives as phytoalexin compounds to ward off disease- causing pathogenic fungi and other microbes.
vii. Soybean uses iso-flavones to stimulate soil- microbe rhizobium to form nitrogen-fixing root nodules.
viii. Activity against enzyme aldose reductase.
Critics claim that iso-flavones increase the incidence of epithelial hyperplasia, which precedes cancerous tumors, and that they cause goiter and hyperthyroidism. Phytoestrogens may actually promote cancer.
Biosynthesis of Iso-Flavone:
Iso-flavones are produced from a branch of the general phenylpropanoid pathway which produces all flavonoid compounds in higher plants. The phenylpropanoid pathway begins from the amino acid phenylalanine, and an intermediate of the pathway, naringenin, is sequentially converted into the iso-flavone genistein by two legume-specific enzymes, iso-flavone synthase and a dehydratase.
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Similarly, another intermediate naringenin chalcone is converted to the iso-flavone daidzein by sequential action of three legume-specific enzymes: chalcone reductase, type II chalcone isomerase, and iso-flavone synthase.
Occurrence of Iso-Flavone:
Most members of the Fabaceae family contain significant quantities of iso-flavones. Analysis of levels in various species has found that the highest levels of genistein and daidzein were found in psoralea (Psoralea corylifolia). Various legumes including kudzu (Pueraria lobata), lupine (Lupinus spp), fava bean (Vica faba), and soy (Glycine max) contained substantial amounts of iso-flavones according to this analysis.
Highly processed foods made from legumes, such as tofu, retained most of their iso-flavone content, with the exception of fermented miso, which actually has increased levels. Other dietary sources of iso-flavones include chick pea (biochanin A), alfalfa (formononetin and coumestrol), and peanut (genistein).
Research on Iso-Flavone:
Isolated phytoestrogen-like iso-flavones are an active research area. A research studied the effect of the isolated soy iso-flavones genistein and daidzein (commonly found in dietary supplements and infant formulas) on adult mice with their ovaries removed.
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The study found the mice had thymic and immune system abnormalities and reduction in immune system activity. The article suggests further research into human phytoestrogen response is warranted. Other research showed a link between soy and health problems in certain animals.
