Genistein

Key takeaways

Genistein belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Genistein to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Genistein from memory before moving on to harder problems.

Reference excerpt

Genistein (C15H10O5) is a plant-derived, aglycone isoflavone. Genistein has the highest content of all isoflavones in soybeans and soy products, such as tempeh. As a type of phytoestrogen, genistein is classed as an endocrine disrupting chemical due to its estrogenic activity in vitro and in vivo. Consequently, excessive consumption of soy products has been linked to disruption of the reproductive organs, such as the uterus, breast, and testis. It was first isolated in 1899 from the dyer's broom, Genista tinctoria; hence, the chemical name. The compound structure was established in 1926, when it was found to be identical with that of prunetol. It was chemically synthesized in 1928. Genistein is a primary secondary metabolite of the Trifolium species and Glycine max (soy).

Natural occurrence Isoflavones, such as genistein and daidzein, occur in soybeans and various other plants, including lupin, fava beans, kudzu, psoralea, Flemingia vestita, and coffee. It is present in red clover.

In soybean products Isoflavone intake from consuming soy products may be as high as 50 mg per day in Asian cuisines, and is increasing in western culture with the shift to vegan and vegetarian diet culture. Genistein has the highest percentage among isoflavones in various soy foods, such as protein concentrate, mature soybeans, and tempeh. It is also prevalent in soy formula which is a suitable alternative to mammalian breast milk. Dietary supplements and infant formulas containing isoflavone extracts are marketed in some countries.

Biosynthesis Genistein is an isoflavone, which are isomers of the large group of plant metabolites called flavones. Its biosynthesis begins in a phenylpropanoid metabolic pathway from the amino acid phenylalanine. After several steps, the intermediate flavanone, naringenin, is formed. It can undergo a rearrangement reaction which converts it first to the unstable hydroxlated isoflavanone, which loses water to give the isoflavone. The enzymes involved are isoflavonoid synthase and 2-hydroxyisoflavanone dehydratase.

Metabolism, bioavailability, and safety Pharmacokinetics studies indicate that genistein blood concentrations peak about 6 hours after a meal containing isoflavones, which are hydrolized in the small intestine and colon. The colonic microbiota during digestion influences the metabolism of genistein and other isoflavones, converting them to metabolites having potential biological effects, such as the extent of estrogenic activity. Although soy products are generally recognized as safe (GRAS), a GRAS determination specifically for genistein has not been reported.

Potential for estrogenic activity Because soy isoflavones have similar chemical structure to 17-β-estradiol, the potential for genistein as an estrogenic (hormone-like) signaling molecule that binds to estrogen receptors within cells, mimicking the action of estrogen, has been the subject of research. Estrogenic effects by genistein may affect the risk of hormone-associated cancers in reproductive tissues, such as the breast, uterus, testis, or prostate gland, while it may also influence bone density and levels of blood lipids. Fetal exposure to 10 mg/kg/day of genistein in rats, believed to be comparable to potential exposure of human infants fed with soy formula, in combination with Di-(2-Ethylhexyl) Phthalate used to produce PVC, led to altered gene and protein expression in neonate and to reduce anogenital distance, a marker of an endocrine disrupting chemical; this effect is more commonly associated with anti-androgens rather than estrogenic compounds.

Human research Although the potential for genistein to have diverse biological activity in humans has been extensively studied, there is only limited evidence of its specific effects. In a 2011-12 analysis, a scientific panel for the European Food Safety Authority found that there was no evidence for a cause-and-effect relationship between the consumption of genistein with other soy isoflavones and 1) protection of DNA, proteins and lipids from oxidative damage, 2) maintenance of normal blood LDL-cholesterol concentrations, 3) changes in vascular function associated with menopause, 4) normal hair growth or 5) bone mineral density. The panel further concluded that there was insufficient evidence that soy isoflavones could affect normal skin tone, respiratory functions, cardiovascular health, or prostate cancer. There is preliminary evidence that consuming soy foods rich in genistein and isoflavones may improve cardiovascular function in postmenopausal women and lower the risk of breast cancer in premenopausal and postmenopausal women. Some studies indicate that supplementation with genistein and soy isoflavones may reduce hot flashes and night sweats during menopause, while there is insufficient evidence for an effect on osteoporosis and cognitive function.

Laboratory research In vitro, genistein is an agonist of the G protein-coupled estrogen receptor, and binds to and activates all three peroxisome proliferator-activated receptor isoforms, α, δ, and γ. Genistein is a tyrosine kinase inhibitor, mostly of epidermal growth factor receptors.

Anthelmintic The root-tuber peel extract of Flemingia vestita is a traditional medicine anthelmintic of the Khasi tribes of India. In research, genistein was found to be the major isoflavone responsible for a deworming property. Genistein was subsequently demonstrated to be effective against intestinal parasites, such as the poultry cestode Raillietina echinobothrida, the pork trematode Fasciolopsis buski, and the sheep liver fluke Fasciola hepatica. It exerts its anthelmintic activity by inhibiting enzymes of glycolysis and glycogenolysis in the parasites.

Related compounds Genistin is the 7-O-beta-D-glucoside of genistein. Wighteone can be described as 6-isopentenyl genistein

See also (S)-Equol Liquiritigenin Menerba

References

Illustrations

Worked examples

Example 1 — a first encounter with Genistein

Start with the simplest possible case. Write down what Genistein claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Genistein before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Genistein ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Genistein

In research: Genistein appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Genistein in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Genistein is common in secondary-school and first-year university syllabi. It links to neighbouring topics 21-Hydroxylase inhibitors, 3α-Hydroxysteroid dehydrogenase inhibitors, Dietary supplements, so understanding it makes those chapters shorter.
In everyday life: Look for Genistein outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Genistein in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Genistein means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Genistein out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Genistein in simple terms?

Genistein (C15H10O5) is a plant-derived, aglycone isoflavone. Genistein has the highest content of all isoflavones in soybeans and soy products, such as tempeh.

Why does Genistein matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Genistein?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Genistein.