Synonyms:5 7-dihydroxy-3- (4-hydroxyphenyl)-4H-1-benzopyran-4-one 4' 5 7-trihydroxyisoflavone
Genistein is an isoflavone belonging to the group of flavonoids. Because of this similarity of the structure of genistein to that of estrogen genistein is also a phytoestrogens together with daidzein. Genistein is the aglycone (without sugar component) of the glycoside genistin.
The main source of genistein are soybeans. Other legumes such as chickpeas contain small amounts of genistein.
Action of Genistein:
Genistein works on several fronts: it acts as a phytoestrogens and as an antioxidant.
The estrogenic activity of genistein has been confirmed in many studies. Of all the isoflavones genistein has the strongest estrogenic activity.
Genistein is a strong antioxidant. Genistein removed damaging free radicals and reduces lipid peroxidation. Only oxidized LDL cholesterol is absorbed by the arterial cells. Prevention of the oxidation of LDL cholesterol will reduce the risk for arteriosclerosis. Gensistein prevents the formation of hearth attacks and strokes by acting as anticlotting agent. Genistein increases the activity of other antioxidant enzymes such as glutathione peroxidase superoxide dismutase and glutathione reductase. Studies have shown that genistein can also influence the growth of cells which are not hormone-dependent. Genistein seems to inhibit the activity of tyrosine kinase which plays an important role in cell growth. Reduction of tyrosine activity will result in a reduced cancer risk.
Genistein seems to reduce the risk for some hormone related cancers principally breast cancer and prostate cancer. Epidemiological studies show that consumption of isoflavones may protect against breast and prostate cancer. High dietary intake of soy products China and Japan are linked with low incidence of these cancers. There are lots of theories to explain the anti-cancer action of genistein: inhibition of angiogenesis inhibition of tyrosine kinases antioxidant property and anti-estrogen action (it is known that estrogen increases risk for certain cancers). Genistein binds with estrogen receptors preventing the estrogen from binding and initiating cancer growth.
The estrogenic effect of genistein may also explain its protective action against osteoporosis.
Genistein is also used to ease menopause symptoms such as hot flushes.
Facts about Genistein:
The main source of genistein is the glucoside genistin. Before genistein can act it first needs to be released from genistin. This normally happens in the stomach (acid hydrolysis) and intestine (action of bacterial enzymes). Some genistein supplements contain genistein which has been hydrolysed in a chemical process.
Genistein PhytoEstrogen (Solaray) Genistein Isoflavone Rich Soyfood Supplement (Source Naturals).
Genistein when marketed as a nutritional supplement is mainly present in the form of its glycoside genistin.
Genistein belongs to the isoflavone class of flavonoids. It is also classified as a phytoestrogen. Phytoestrogens are plant-derived nonsteroidal compounds that possess estrogen-like biological activity. Genistein has been found to have both weak estrogenic and weak anti-estrogenic effects.
Genistein is the aglycone (aglucon) of genistin. The isoflavone is found naturally as the glycoside genistin and as the glycosides 6'-O-malonylgenistin and 6'-O-acetylgenistin. Genistein and its glycosides are mainly found in legumes such as soybeans and chickpeas. Soybeans and soy foods are the major dietary sources of these substances. Nonfermented soy foods such as tofu contain higher levels of the genistein glycosides while fermented soy foods such as tempeh and miso contain higher levels of the aglycone.
Genistein is a solid substance that is practically insoluble in water. Its molecular formula is C15H10O5 and its molecular weight is daltons. Genistein is also known as 5 7-dihydroxy-3- (4-hydroxyphenyl)-4H-1-benzopyran-4-one and 4' 5 7-trihydroxyisoflavone. Genistin which is the 7-beta glucoside of genistein has greater water solubility than genistein. Genistein has the following structural formula:
ACTIONS AND PHARMACOLOGYACTIONS
Genistein has estrogenic and antioxidant activities. It may also have anticarcinogenic anti-atherogenic and anti-osteoporotic activities.
MECHANISM OF ACTION
Genistein has weak estrogenic activity as measured in in vivo and in vitro assays. In vivo its estrogenic activity is one-third that of glycitein and four times greater than that of daidzein.
Genistein has been found to have a number of antioxidant activities. It is a scavenger of reactive oxygen species and inhibits lipid peroxidation. It also inhibits superoxide anion generation by the enzyme xanthine oxidase. In addition genistein in animal experiments has been found to increase the activities of the antioxidant enzymes superoxide dismutase glutathione peroxidase catalase and glutathione reductase.
Several mechanisms have been proposed for genistein's putative anticarcinogenic activity. These include upregulation of apoptosis inhibition of angiogenesis inhibition of DNA topoisomerase II and inhibition of protein tyrosine kinases. Genistein's weak estrogenic activity has been suggested as another mechanism for genistein's putative anti-prostate cancer activity. In addition to the above mechanisms other mechanisms of genistein's putative anti-prostate cancer activity include inhibition of nuclear factor (NF)-Kappa B in prostate cancer cells downregulation of TGF (transforming growth factor)-beta and inhibition of EGF (epidermal growth factor)-stimulated growth. Genistein's anti-estrogenic action may be another possible mechanism to explain its putative anti-breast cancer activity. In the final analysis the mechanism of genistein's putative anticarcinogenic activity is unclear.
The possible anti-atherogenic activity of genistein may be attributed in part to its antioxidant activity. Genistein may have some lipid-lowering activity but the mechanism of this is unclear. The weak estrogenic activity of genistein may also contribute to its possible anti-atherogenic action.
Genistein's weak estrogenic effect may help protect against osteoporosis by preventing bone resorption and promoting increased bone density. Genistein has been found to maintain trabecular bone tissue in rats. However the mechanism of genistein's possible anti-osteoporotic effect is unclear.
The pharmacokinetics of genistein in humans is complex and not well understood. The major dietary and supplemental form of genistein is the glycoside genistin. Some genistin may be hydrolyzed by hydrochloric acid in the stomach to genistein and some may be hydrolyzed by beta-glucosidases in food to genistein. Most of ingested genistin however is delivered to the large intestine intact. In the large intestine bacterial beta-glucosidases hydrolyze genistin to genistein. Genistein is either absorbed or further metabolized in the large intestine to dihydrogenistein and 6'-hydroxy-O-desmethylangolensin. Genistein which is absorbed from the large intestine and small intestine is eventually transported to the liver. There it undergoes conjugation with glucuronate and sulfate via hepatic phase II enzymes (UDP-glucuronosyltransferases and sulfotransferases). The glucuronate and sulfate conjugates of genistein are excreted in the urine and in the bile. The genistein conjugates may be deconjugated to release genistein which may be reabsorbed via the enterohepatic circulation.
There is considerable individual variation in the absorption and metabolism of ingested genistin and genistein. There are some data suggesting that genistein may be more bioavailable than genistin. However other data suggest that the extent of absorption of genistein is similar for the aglycone and the glucoside forms. There are little data available on the tissue distribution of genistein.
INDICATIONS AND USAGE
There is a growing body of in vitro and animal studies suggesting that genistein may be helpful in preventing and treating some cancers principally breast and prostate cancers. The clinical studies that might support or refute claims that genistein has anti-atherogenic properties and that it can safely and effectively be used as 'natural' estrogen-replacement therapy have not been conducted. There are however preliminary data suggesting that soy isoflavones including genistein may be helpful in some problems associated with menopause including osteoporosis and 'hot flashes.' See Soy Isoflavones.
Epidemiological data have long suggested that dietary isoflavones may confer protection against various cancers especially breast and prostate cancer. High dietary intake of soy products in parts of Asia significantly correlated with reduced incidence of both breast and prostate cancers. Epidemiological data have not been entirely consistent in this regard but most studies suggest protective effects. Some studies have shown moreover that this protection is lost in the second generation of those Asians emigrating to the United States.
These data led to experimental animal studies demonstrating protective effects. In one study genistein perinatally fed to rats significantly protected offspring from subsequent chemically induced mammary cancers. These researchers concluded that adequate perinatal exposure to genistein can confer permanent protective effects against breast cancer. They have further speculated that protective effects in humans with respect to breast cancer specifically may depend upon exposure to genistein early in life. More research is needed to clarify this issue.
A number of studies have shown that genistein can inhibit prostate cancer-cell growth in vitro. Some recent in vitro studies suggest that genistein may be both chemopreventive and therapeutic in prostate cancers regardless of androgen responsiveness. Clinical trials are needed.
Also see Soy Isoflavones.
CONTRAINDICATIONS PRECAUTIONS ADVERSE REACTIONS
Genistein is contraindicated in those who are hypersensitive to any component of a genistin or genistein-containing product.
Pregnant women and nursing mothers should avoid the use of genistein/genistin supplements pending long-term safety studies.
Men with prostate cancer should discuss the advisability of the use of genistein/genistin supplements with their physicians before deciding to use them.
Women with estrogen receptor-positive tumors should exercise caution in the use of genistein/genistin supplements and should only use them if they are recommended and monitored by a physician.
Genistein/genistin intake has been associated with hypothyroidism in some.
DOSAGE AND ADMINISTRATION
Genistein is available in a few different isoflavone formulas. A standard soy isoflavone formula contains genistein mainly in the form of genistin as well as daidzin and glycitin. The percentages of the various isoflavones present in this soy formula reflect the percentages of these substances as found in soybeans and are: genistin about 50%; daidzin about 38%; and glycitin about 12%. A 50 mg dose of soy isoflavones—a typical daily dose—provides 25 mg of genistin 19 mg of daidzin and about 6 mg of glycitin. Usually 40% of the formula is comprised of soy isoflavones. Therefore to get a dose of 50 mg of soy isoflavones one needs 125 mg of the soy preparation.
Smaller amounts of genistein as the aglycone are available in some red clover preparations (see Biochanin A)Interacting
Genistein is one of several known isoflavones. Isoflavones compounds such as genistein and daidzein are found in a number of plants but soybeans and soy products like tofu and textured vegetable protein are the primary food source. Soy isoflavones are a group of compounds found in and isolated from the soybean. Besides functioning as antioxidants many isoflavones have been shown to interact with animal and human estrogen receptors causing effects in the body similar to those caused by the hormone estrogen. Soy isoflavones also produce non-hormonal effects.
Isoflavones acts as antioxidants to counteract damaging effects of free radicals in tissues. Isoflavones can act like estrogen in stimulating development and maintenance of female characteristics or they can block cells from using other forms of estrogen. Isoflavones also have been found to have antiangiogenic effects (blocking formation of new blood vessels) and may 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).
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. Initial studies of soy isoflavone mixtures containing genistein daidzein and glycitein have found them safe for human use. Laboratory studies using animals models have shown that both soy and isoflavones 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).
Estrogen has a powerful protective effect on bone. In women osteoporosis most often occurs after menopause when the ovaries stop producing estrogen. Animal studies as well as a double-blind placebo-controlled trial in humans suggest that genistein can help restore bone protection.
In one twelve-month study 90 women aged 47-57 were given genistein standard hormone replacement therapy (HRT) or placebo. 49 The results showed that genistein increased bone density to approximately the same extent as HRT. No adverse effects on the uterus or breast were seen.
Interestingly unlike estrogen which primarily helps prevent the destruction of bone evidence suggests that genistein may also assist in creating new bone.
However in one animal study while a small dose of genistein helped protect the rats' bones a larger dose of genistein seemed to have the opposite effect—causing increasing bone destruction. Studies in humans are needed to determine whether genistein is truly effective and to find the optimum dose.
Other studies have evaluated the effects of soy products containing other constituents besides genistein. For more information see the full soy article.
Genistein may help reduce risk of various forms of cancer. In one study newborn female rats treated with genistein had less breast cancer later in life than those treated with placebo. 16 However other studies suggest that genistein or other isoflavones could promote breast cancer under certain conditions. (See Safety Issues) 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 mutations. Some cancer patients whose chemotherapy drugs inhibited topoisomerase later developed leukemia. NCI researchers have completed animal studies on genistein with no adverse effects being seen. Clinical trials with people are in progress.
In the test tube genistein has been found to suppress the growth of a wide range of cancer cells including forms of cancer that are not affected by estrogen. 1112 For example genistein has been found to inhibit skin cancer when it was applied to the skin of mice or fed to rats. 1415 Furthermore in test tube studies genistein has been found to enhance the effects of chemotherapy drugs. 13
One double-blind placebo-controlled study found that use of genistein helped relax the artery wall (the endothelium) an effect that would be expected to help prevent heart disease. 54 In addition test tube studies suggest that genistein may help keep cholesterol in the blood from depositing in blood vessel walls. 20 Finally very early test tube research suggests genistein may also inhibit the formation of blood clots which are a major cause of heart attacks.
Clinical trials animal studies cell-culture experiments and epidemiological studies have provided evidence for the following physiological effects of genistein:
reducing symptoms of allergic asthma
strengthening bone due to estrogen deficiency especially in the spine
protection of nerve cells from damage caused by hormone shortages and Alzheimer’s proteins
inhibition of growth and spread of various cancers — including cancer of the ovaries colon prostate thyroid skin and head and neck; non-Hodgkin’s lymphoma malignant melanoma certain leukemias and lung cancers and possibly breast cancer
counteracting the effects of the DeltaF508 mutation that causes cystic fibrosis
lowering body fat
improving insulin responses to blood sugar
lowering total cholesterol and LDL levels increasing HDL levels
decreasing symptoms of Raynaud’s Disease
inhibiting growth of atherosclerotic plaques in blood vessels
increasing arterial elasticity lowering high blood pressure
preventing aging effects of UV light on skin
enhancing the bioavailability of many hard-to-absorb substances
Some of these effects of genistein are still controversial since they were seen in some studies and not in others. Such discrepancies often are the result of inadequate dosing.
Bone strengthening effects were seen using various isoflavone regimens — one such study used 44 mg/day of isoflavones including 1 mg genistein and 0.5 mg daidzein; another study used 54 mg/day of pure genistein. Beneficial effects on cholesterol were seen when 42 mg/day of genistein was used.
Other isoflavones such as daidzein and glycitein share many of genistein’s actions in the body.
One study suggests that the supplement I3C (indole-3-carbinol) works synergistically with genistein to suppress estrogen-related cancers.
After contact with skin wash immediately with plenty of water. Gently and thoroughly wash the contaminated skinwith running water and non-abrasive soap. Be particularly careful to clean folds crevices creases and groin.
Cover the irritated skin with an emollient. If irritation persists seek medical attention. Wash contaminatedclothing before reusing.
Serious Skin Contact:
Wash with a disinfectant soap and cover the contaminated skin with an anti-bacterial cream. Seek medicalattention.Inhalation: Allow the victim to rest in a well ventilated area. Seek immediate medical attention.
high protein diet provides enough amino acids to replace the degenerated tissue fibers. Soy also helps fight the effects of UV radiation on the skin by acting as antioxidants that mop up free radicals. Soy contains isoflavones like genistein which are especially potent in this regard. Other components of soy like phytates saponins and lignins also have antioxidant properties. Thus soy protein helps strengthen the skin by decreasing the wear and tear of the tissue proteins.
Genistein. An active ingredient found in soy extract that stimulates collagen production and diminishes collagen breakdown. In addition to free radicals skin contains naturally occurring enzymes that erode collagen. Genistein isolated by Dr. Genistein in Switzerland has been shown to block and diminish these collagen-destroying enzymes significantly. Also thickens skin dramatically by working like estrogen but without the negative side effects of HRT (hormone replacement therapy). Gentle for all skin types and nonirritating; works well with all other anti-aging ingredients.
genistein (to build collagen and elastin) and alpha- or beta-hydroxy acids (to speed skin cell turnover).
The soy serum's role in skin firming is explained this way: sun damaged skin has rupture of collagen fibres and functionally impaired fibroblasts (the stimulants to collagen production). Clinical research concludes that ECM can influence and stabilize fibroblasts via almost incredible 'growth signals' --- and thus increase collagen and elasticity
The presence of specific ingredients as Genistein and Ceramides helps skin to combat the natural lack of estrogens and reduce the skin aging signs due to the hormonal deficit by reinforcing the epidermic horny layer and increasing the natural protection factors. The skin look will become more compact and fresh.
The Genistein confimation has sour egg white(the tyrosine protein kinase) of the Lao An of repress and stop the tumor cell to increase to get lately and afferently around.Therefore for breast cancer and shoot to protect a gland cancer urine bladder cancer large intestine cancer rectum cancer colon cancer lung cancer the prostate gland cancer and the skin cancers all have the result of the prevention.
The research of the American University of Michigan also confirms that live type isoflavone Genistein no matter in the cell or outside can repress the prostate gland cancer cell to increase to get effectively.
According to the research of the Japanese University of Tokyo the soybean isoflavone has the function of the estrogen but has no cancer-causing risk.Can improve menopause condition of illness effectively.Can also activate manufacturing skeleton cell repress eclipse bone cell and keep bone substance from running off in addition prevent a bone soft effectively.
According to the research of the Epidemiology the soybean food let female breast cancer in Asia contract a rate lower than Euro-American region the soybean isoflavone that is among them think to is a main factor and the anti-cancer function of the soybean isoflavone mainly is it has estrogen of regulate to synthesize the metabolism and anti- oxidize live reason with the result that.
The researcher also finds that the soybean isoflavone can reduce blood in the content of the content the increment high definition cholesterol HDL of the low density cholesterol LDL preventing the occurrence of the cardiovascular disease effectively.The soybean isoflavone vegetable can help the water Na and the excretion of the potassium the result of the beneficial urine so be also the diuretic usage.