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 染料木素.Genistein
Phytochemical:Genistein
Synonyms:5, 7-dihydroxy-3- (4-hydroxyphenyl)-4H-1-benzopyran-4-one,
4', 5, 7-trihydroxyisoflavone
MW:270.24
FormulaC15H10O5
Description:
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.
Distribution:
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.
TRADE NAMES
Genistein PhytoEstrogen (Solaray), Genistein Isoflavone Rich Soyfood
Supplement (Source Naturals).
DESCRIPTION
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.
PHARMACOKINETICS
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
INDICATIONS
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
CONTRAINDICATIONS
Genistein is contraindicated in those who are hypersensitive to any
component of a genistin, or genistein-containing product.
PRECAUTIONS
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).
Osteoporosis
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.
Cancer
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. 11,12 For example, genistein has been found to
inhibit skin cancer when it was applied to the skin of mice or fed
to rats. 14,15 Furthermore, in test tube studies, genistein has been
found to enhance the effects of chemotherapy drugs. 13
Heart Disease
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
breast enlargement
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.
Skin Contact:
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.
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