5 Main Examples of Iso-Flavone (With Functions)

This article throws light upon the five main examples of iso-flavone. The examples are: 1. Genistein 2. Daidzein 3. Biochanin A 4. Puerarin 5. Formononetin.

Iso-Flavone Example # 1. Genistein:

Genistein is one of several known iso-flavones.

Source:

Soybeans and soy products like tofu and tex­tured vegetable protein being the primary food source.

Functions:

i. As antioxidant.

ii. Many iso-flavones have been shown to inter­act with animal and human estrogen recep­tors, causing effects in the body similar to those caused by the hormone estrogen in stimulat­ing development and maintenance of female characteristics or they can block cells from using other forms of estrogen.

iii. Have anti-angiogenic effects (blocking forma­tion of new blood vessels).

iv. Block the uncontrolled cell growth associat­ed with cancer, most likely by inhibiting the activity of substances in the body that regu­late cell division and cell survival (growth fac­tors).

v. Studies show that groups of people who eat large amounts of soy-based products have lower incidences of breast, colon, endome­trial, and prostate cancers than the general (US) population.

vi. Inhibition of protein tyrosine kinases (PTK).

vii. Blocking the PLC activation and formation of inositol triphosphate (IP3) and diacylglycerol (DAG).

Research:

I. Initial studies of soy iso-flavone mixtures con­taining genistein, daidzein, and glycitein have found them safe for human use. Laboratory studies using animals models have shown that both soy and iso-flavones can be protective against cancer when given during early life but can stimulate response to cancer-causing chemicals when given during fetal develop­ment or when circulating levels of estrogen are low (menopause).

II. Some recent studies have raised the concern that genistein might potentially increase the risk of leukemia, because it can inhibit an enzyme topoisomerase that protects DNA from mutation,

III. Genistein influences several targets in living cells. One important function is the inhibition of several tyrosine kinase.

IV. Genistein inhibits the mammalian hexose transporter GLUT1 and contraction of several types of smooth muscles.

V. Genistein can bind to CFTR receptors. This binding causes the channel to become per­manently open causing “free-flow” of chlo­ride ions through the channel.

Iso-Flavone Example # 2. Daidzein:

Daidzein is one of several known iso-flavones.

Source:

Soybeans and soy products like tofu, and textured vegetable protein. Coumestrol is a natural organic compound in the class of phytochemicals known as coumestans. It has garnered research interest because of its es­trogenic activity and its prevalence in some foods, such as soybeans. Coumestrol was first identified by E.M.Bickoff in alfalfa in 1957.

Source:

Legumes, soybeans, brussel sprouts, spinach and clover.

Functions:

i. Coumestrol is a phytoestrogens, mimicking the biological activity of estrogens.

ii. The chemical shape of coumestrol orients its two hydroxy groups in the same position as the two hydroxy groups in estradiol, allowing it to inhibit the activity of aromatase and hydroxysteroid dehydrogenase. These enzymes are involved in the biosynthesis of steroid hormones, and inhibition of these enzymes results in the modulation of hormone produc­tion.

Iso-Flavone Example # 3. Biochanin A:

Biochanin A belongs to the iso-flavone class of fla­vonoids. It is also classified as a phytoestrogen since it is a plant-derived non-steroidal compound that possesses estrogen-like biological activity. Biochanin A has been found to have weak estro­genic activity.

It is a solid substance that is virtual­ly insoluble in water. Its molecular formula is C₁₆H₁₂O₅. It is the 4′-methyl ether of genistein. Biochanin A is also known as 5, 7-dihydroxy-4′- meth-oxy-iso-flavone and 5, 7-dihydroxy-4′ -meth-oxy-3- (4-hydroxyphenyl)-4H-1 -benzopyran-4- one (Gotoh et al., 1998).

Sources:

Soy products and certain legumes, most notably red clover or Trifolium pratense. Red clover con­tains, in addition to biochanin A, the iso-flavones genistein, daidzein and formononetin (methoxy daidzein). These iso-flavones are present in red clover in the form of glycosides.

However, when the leaves are crushed during the preparation of red clover iso-flavone extracts, the glycosides un­dergo enzymatic hydrolysis, and the final prepa­ration principally contains the aglycones.

Actions:

i. Estrogenic

ii. Antioxidant

iii. Anti-carcinogenic

iv. Anti-atherogenic

v. Anti-osteoporotic

vi. In comparison with other iso-flavones, such as genistein and daidzein, biochanin A might be expected to have possible anti-osteoporotic activity. This might be due, in part, to its weak estrogenic activity.

Precautions:

i. Pregnant women and nursing mothers should avoid the use of biochanin A-containing sup­plements.

ii. Women with estrogen receptor-positive tu­mors should exercise caution in the use of biochanin A-containing supplements and should use them only if they are recommend­ed and monitored by a physician.

Iso-Flavone Example # 4. Puerarin:

8-beta-D-Glucopyranosyl-7-hydroxy-3-(4-hydroxyphenyl)-4H-1 -benzopyran-4-one.

Iso-Flavone Example # 5. Formononetin:

7-Hydroxy-3-(42-methoxyphenyl)-4H-benzopyran-4-one; 7-Hydroxy-3-(4-methoxyphenyl) chromone; 7-Hydroxy-4′-meth-oxy-iso-flavone; Dadein 4′-methyl ether. A non-steroidal phytoestrogenic isoflavone found in soy-based food prod­ucts.

Has been shown to interact with human es­trogen receptor with relatively low potency. In­duces mammary gland proliferation in mice. In­hibits lecithin peroxidation induced by hydroxyl radicals. Also acts as a selective inhibitor of g- isoform of alcohol dehydrogenase.

Daidzein:

Daidzein is the aglycone (aglucon) of daidzin. Daidzein is an iso-flavone and a phytoestrogen. It is a plant-derived nonsteriodal compound. Daid­zein is found naturally as the glycoside daidzin and as the glycosides 6″-0-malonylgenistin and 6″-0-acetyldaidzin.

Daidzein is a solid substance that is insoluble in water whereas daidzin dem­onstrates some water solubility. When in nutrition­al supplements, Daidzein often appears as daid­zin, in a beta-glucoside form. White to beige pow­der, which is soluble in DMSO or dilute aqueous base and insoluble in water.

Sources:

Legumes, such as soybeans and chickpeas and Radixpuerariae, an old Chinese, herbal medicine made from the roots of Kudzu.

Uses:

i. Antioxidant

ii. Decreases blood alcohol levels and shortens sleep time induced by ethanol intoxication.