Anti-Cancer Agents from Natural Sources
Rohit Dutt, Anil K. Sharma, Raj K. Keservani, Vandana Garg in Promising Drug Molecules of Natural Origin, 2020
Isoflavones are a subcategory of flavonoids, also called phytoestrogens, as many of these compounds have estrogenic activity in human. Isoflavonoids have a B-ring attached to a C3 carbon (C6-C3-C6 backbone) (Figure 5.20). Isoflavones can be found in foods which include dairy products, oils, and legumes. Upto now, many isoflavones have been tested for their anticancer potential. Their anticancer potential arises from their functional similarity to estrogens, which bind to estrogen receptor (ER)-beta rather than ER-alpha. Two commonly known isoflavones viz. genistein and daidzein are the major isoflavones in soybean. Ardito et al. (2017)assayed the efficacy of genistein in tongue (oral) cancer, which is an aggressive SCC, although having a comparatively reasonable 5-year survival rate which is 84% for non-spread cancer, 64% for that has spread to nearby lymph nodes, and 39% for cancer that has metastasized to other regions of the body. Early stage indications are jaw pain, lump inside the mouth, white or red gums, and difficulty chewing or moving the tongue, before they are fully diagnosed (Tongue Cancer, 2018). As limited chemotherapeutic agents are available for this cancer, new drugs are essential to ensure complete eradication (Oral Cancer: Your chances for recovery (prognosis), 2018). Genistein at 20-50 µM concentration inhibited cell adhesion by preventing cells to stink with one another. Cell life was reduced significantly at a moderate concentration of genistein. Metastasis was also inhibited due to down-regulation of an a few important proteins, like OCT4.
Formulated Natural Selective Estrogen Receptor Modulators: A Key To Restoring Women’s Health
Megh R. Goyal, Durgesh Nandini Chauhan in Plant- and Marine-Based Phytochemicals for Human Health, 2018
Isoflavones are naturally occurring isoflavonoids, which are the most studied class of phytoestrogens and are found almost exclusively in the family of Leguminosae.34 The flavonoids belong to large chemical class and are formed through the phenylpropanoid-acetate pathway by chalcone synthase and condensation reactions with malonyl-CoA. Isoflavones are produced through general phenylpropanoid pathway that produces 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 isoflavone genistein by two legume-specific enzymes: isoflavone synthase and a dehydratase. Similarly, another intermediate naringenin chalcone is converted to the isoflavone daidzein by sequential action of three legume-specific enzymes: chalcone reductase, type II chalcone isomerase, and isoflavone synthase. Plants use isoflavones and their derivatives as phytoalexin compounds to ward off disease-causing pathogenic fungi and other microbes. The isoflavonoids are subclass of flavonoids that differ in the position of one phenolic ring, which has shifted from C-3 to C-2. The isoflavonoids from legumes, that includes genistein-2 and daidzein, are most studied phytoestrogens. They can exist as glucosides or as glycones that are easily transported across intestinal epithelial cells and are hydrolyzed in the gut.46
Herbs in Cancer Therapy
Anil K. Sharma, Raj K. Keservani, Surya Prakash Gautam in Herbal Product Development, 2020
Flavonoids, or bioflavonoids, include about 3000 natural phenolic structures. They commonly occur in almost every vegetable, fruit, and herb. They are also found in tea and coffee. Flavonoids constitute a considerable part of our daily dietary value, mostly in the form of quercetin (Kühnau 1976). They act as anti-inflammatory, enzyme inhibitors, that can potentially improve capillary resistance and battle free radicals. Flavonoids are classified into flavanones, flavones, isoflavones, flavonols, flavanols, and anthocyanidins. Flavanones have limited distribution, found mainly in citrus fruits such as lemons and oranges (Hollman et al. 1997). Flavones are widely distributed, such as luteolin and apigenin. Isoflavones include genistein, which can potentially inhibit human prostate cancer cells, and daidzein. Food rich in isoflavones includes legumes such as soy. Flavonols are found as naturally occurring glycosides, and the major ones include kaempferol and quercetin. Flavanols, or flavan-3-ols, have limited distribution and are found in tea, apples, broccoli, etc. Catechins such as epigallocatechin gallate (EGCG) are an example of flavanols. Anthrocyanidins are red-blue pigments found in berries. They are responsible for pigmentation in fruits.
Effect of Daily Exposure to an Isolated Soy Protein Supplement on Body Composition, Energy and Macronutrient Intake, Bone Formation Markers, and Lipid Profile in Children in Colombia
Published in Journal of Dietary Supplements, 2019
Wilson Mejía, Diana Córdoba, Paola Durán, Yersson Chacón, Diego Rosselli
The concern of pediatricians when recommending the use of a nutritional supplement based on soy protein is on possible hormonal effects of the exposure of children to phytoestrogens contained in these formulas (McCarver et al., 2011). Isoflavones are phytoestrogens. The isoflavones are bound to the proteins through noncovalent forces and co-precipitate with the soy protein isolate during the process. Isoflavone content in soy can be obtained both as aglycone (genistein, daidzein, and glycitein) and glycone forms (linked through a glycosidic sugar: genistin, daidzein, and glycitin) (Setchell, 1998). In the case of aglycone forms, genistein content is between 52% to 61%, followed by daidzein 31% to 42%, and glycitein 5% to 9%. In nutritional supplements, most of the isoflavones are in a glycoside form; once in the gastrointestinal tract, the action of specific bacteria β-glucosidases hydrolyzes them to release the aglycone forms, which are then biologically active (Vitale et al., 2013).
Genistein for glycolipid metabolism in postmenopausal women: a meta-analysis
Published in Climacteric, 2021
Phytoestrogens are a group of biological compounds with similar structures to estrogen and have estrogen receptor modulator properties9. Isoflavone is a kind of phytoestrogen mainly obtained from soybeans. Research has shown that dietary intake of isoflavones in soy products was associated with lower risk of cardiovascular disease in women10,11. Genistein is a main constitute of isoflavone in soybeans. Animal and human studies also showed that isolated genistein could ameliorate unfavorable glycolipid metabolism and had cardiovascular protective effects12–15. Genistein had high affinity and selectivity with estrogen receptor β (ERβ), thus it could not exert estrogenic effects to breast and uterine tissues that had more ERα in the meanwhile16–18. In view of its efficacy and safety profile, genistein has drawn more attention in recent years. However, some other studies indicated that genistein had little effect on glycolipid metabolism19–21. Also, most studies did not isolate genistein from other isoflavones. For this inconsistency, we designed a meta-analysis of randomized controlled trials (RCTs) to evaluate the effects of isolated genistein on glycolipid metabolism in postmenopausal women.
The effects of soybean isoflavones and 17β-estradiol in uterus and mammary glands of diabetic rat models
Published in Gynecological Endocrinology, 2018
Adriana Aparecida Ferraz Carbonel, Patrícia Daniele Azevedo Lima, Jung Jin Lim, Luiz Fernando Portugal Fuchs, Ana Paula Ribeiro Paiotti, Gisela Rodrigues da Silva Sasso, Ricardo Santos Simões, José Maria Soares Junior, Edmund Chada Baracat, Manuel de Jesus Simões
Isoflavones are phytochemicals found in various legumes including soybean, kudzu, alfalfa, chickpeas, and peanuts. Soy foods contain high levels of phytoestrogens, mainly isoflavones, whose chemical structures mimic 17β-estradiol and compete with endogenous estrogen that bind to estrogen receptors [1]. However, in an estrogen-deprived environment, isoflavones may exert estrogen-like effects, serving as estrogen agonists [2]. Isoflavone has been known to be associated with a reduced risk of breast tumor, including protection against menopausal symptoms, osteoporosis, cardiovascular disease, atherosclerosis, hyperlipidemia, and cancer [3,4]. There are substantial evidence that soy foods have the potential to address several conditions and diseases associated with menopausal transition [4].