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Gong Y, Lv J, Pang X, Zhang S, Zhang G, Liu L, Wang Y, Li C. Advances in the Metabolic Mechanism and Functional Characteristics of Equol. Foods 2023; 12:2334. [PMID: 37372545 DOI: 10.3390/foods12122334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 06/07/2023] [Accepted: 06/08/2023] [Indexed: 06/29/2023] Open
Abstract
Equol is the most potent soy isoflavone metabolite and is produced by specific intestinal microorganisms of mammals. It has promising application possibilities for preventing chronic diseases such as cardiovascular disease, breast cancer, and prostate cancer due to its high antioxidant activity and hormone-like activity. Thus, it is of great significance to systematically study the efficient preparation method of equol and its functional activity. This paper elaborates on the metabolic mechanism of equol in humans; focuses on the biological characteristics, synthesis methods, and the currently isolated equol-producing bacteria; and looks forward to its future development and application direction, aiming to provide guidance for the application and promotion of equol in the field of food and health products.
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Affiliation(s)
- Yining Gong
- Key Laboratory of Dairy Sciences, Ministry of Education, College of Food Science, Northeast Agricultural University, Harbin 150030, China
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, No. 2 Yuan Ming Yuan West Road, Beijing 100193, China
| | - Jiaping Lv
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, No. 2 Yuan Ming Yuan West Road, Beijing 100193, China
| | - Xiaoyang Pang
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, No. 2 Yuan Ming Yuan West Road, Beijing 100193, China
| | - Shuwen Zhang
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, No. 2 Yuan Ming Yuan West Road, Beijing 100193, China
| | - Guofang Zhang
- Key Laboratory of Dairy Sciences, Ministry of Education, College of Food Science, Northeast Agricultural University, Harbin 150030, China
| | - Libo Liu
- Key Laboratory of Dairy Sciences, Ministry of Education, College of Food Science, Northeast Agricultural University, Harbin 150030, China
| | - Yunna Wang
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, No. 2 Yuan Ming Yuan West Road, Beijing 100193, China
| | - Chun Li
- Key Laboratory of Dairy Sciences, Ministry of Education, College of Food Science, Northeast Agricultural University, Harbin 150030, China
- Heilongjiang Green Food Science Research Institute, Harbin 150030, China
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Lephart ED. Phytoestrogens (Resveratrol and Equol) for Estrogen-Deficient Skin-Controversies/Misinformation versus Anti-Aging In Vitro and Clinical Evidence via Nutraceutical-Cosmetics. Int J Mol Sci 2021; 22:11218. [PMID: 34681876 PMCID: PMC8538984 DOI: 10.3390/ijms222011218] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 10/10/2021] [Accepted: 10/14/2021] [Indexed: 12/17/2022] Open
Abstract
The overarching theme for this review is perspective. Superfoods (a marketing term for fruits and vegetables, etc.) have a positive connotation, while many superfoods contain phytoestrogens, a term that is alarming to the public and has a negative connotation because phytoestrogens are endocrine-disruptors, even though they are strong antioxidants that have many health benefits. To understand phytoestrogens, this paper provides a brief summary of the characteristics of: (a) estrogens, (b) estrogen receptors (ER), (c) estrogen-deficient skin, (d) how perspective(s) get off track, (e) phytoestrogen food sources, and (f) misconceptions of phytoestrogens and food safety, in general, that influence person(s) away from what is true. Finally, a brief history of cosmetics to nutraceuticals is covered plus the characteristics of phytoestrogens, resveratrol and equol on: (g) estrogen receptor binding, (h) topical and oral dosing, and (i) in vitro, molecular mechanisms and select clinical evidence, where both phytoestrogens (resveratrol and equol) demonstrate promising applications to improve skin health is presented along with future directions of nutraceuticals. Perspective is paramount in understanding the controversies associated with superfoods, phytoestrogens, and endocrine-disruptors because they have both positive and negative connotations. Everyone is exposed to and consumes these molecules everyday regardless of age, gender, or geographic location around the world, and how we understand this is a matter of perspective.
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Affiliation(s)
- Edwin D Lephart
- Department of Cell Biology, Physiology and The Neuroscience Center, College of Life Sciences, Brigham Young University, Provo, UT 84602, USA
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Pharmacological Effects and Potential Clinical Usefulness of Polyphenols in Benign Prostatic Hyperplasia. Molecules 2021; 26:molecules26020450. [PMID: 33467066 PMCID: PMC7829696 DOI: 10.3390/molecules26020450] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/12/2021] [Accepted: 01/13/2021] [Indexed: 02/07/2023] Open
Abstract
Benign prostatic hyperplasia (BPH) is arguably the most common benign disease among men. This disease is often associated with lower urinary tract symptoms (LUTS) in men and significantly decreases the quality of life. Polyphenol consumption reportedly plays an important role in the prevention of many diseases, including BPH. In recent years, in addition to disease prevention, many studies have reported the efficacy and safety of polyphenol treatment against various pathological conditions in vivo and in vitro. Furthermore, numerous studies have also revealed the molecular mechanisms of the antioxidant and anti-inflammatory effects of polyphenols. We believe that an improved understanding of the detailed pharmacological roles of polyphenol-induced activities at a molecular level is important for the prevention and treatment of BPH. Polyphenols are composed of many members, and their biological roles differ. In this review, we first provide information regarding the pathological roles of oxidative stress and inflammation in BPH. Next, the antioxidant and anti-inflammatory effects of polyphenols, including those of flavonoids and non-flavonoids, are discussed. Finally, we talk about the results and limitations of previous clinical trials that have used polyphenols in BPH, with particular focus on their molecular mechanisms of action.
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Borovskaya TG, Kamalova SI, Grigor’eva VA, Poluektova ME, Vychuzhanina AV, Kuchin AV, Chukicheva IY, Buravlev EV, Fomina TI, Plotnikov MB, Goldberg VE, Dygai AM. Effectiveness of Phenolic Antioxidants in Experimental Model of Benign Prostatic Hyperplasia. Bull Exp Biol Med 2019; 167:606-609. [DOI: 10.1007/s10517-019-04580-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Indexed: 12/17/2022]
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Rhodobacter sphaeroides Extract Lycogen™ Attenuates Testosterone-Induced Benign Prostate Hyperplasia in Rats. Int J Mol Sci 2018; 19:ijms19041137. [PMID: 29642620 PMCID: PMC5979474 DOI: 10.3390/ijms19041137] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 03/25/2018] [Accepted: 04/05/2018] [Indexed: 12/12/2022] Open
Abstract
Benign prostate hyperplasia (BPH) is one of the most common urological problems in mid-aged to elderly men. Risk factors of BPH include family history, obesity, type 2 diabetes, and high oxidative stress. The main medication classes for BPH management are alpha blockers and 5α-reductase inhibitors. However, these conventional medicines cause adverse effects. Lycogen™, extracted from Rhodobacter sphaeroides WL-APD911, is an anti-oxidant and anti-inflammatory compound. In this study, the effect of Lycogen™ was evaluated in rats with testosterone-induced benign prostate hyperplasia (BPH). Testosterone injections and Lycogen™ administration were carried out for 28 days, and body weights were recorded twice per week. The testosterone injection successfully induced a prostate enlargement. BPH-induced rats treated with different doses of Lycogen™ exhibited a significantly decreased prostate index (PI). Moreover, the Lycogen™ administration recovered the histological abnormalities observed in the prostate of BPH rats. In conclusion, these findings support a dose-dependent preventing effect of Lycogen™ on testosterone-induced BPH in rats and suggest that Lycogen™ may be favorable to the prevention and management of benign prostate hyperplasia.
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Yalamanchili C, Chittiboyina AG, Chandra Kumar Rotte S, Katzenellenbogen JA, Helferich WG, Khan IA. A chiral pool approach for asymmetric syntheses of both antipodes of equol and sativan. Tetrahedron 2018. [DOI: 10.1016/j.tet.2018.03.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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N-Butanol and Aqueous Fractions of Red Maca Methanolic Extract Exerts Opposite Effects on Androgen and Oestrogens Receptors (Alpha and Beta) in Rats with Testosterone-Induced Benign Prostatic Hyperplasia. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2017; 2017:9124240. [PMID: 29375645 PMCID: PMC5742461 DOI: 10.1155/2017/9124240] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 11/13/2017] [Indexed: 12/18/2022]
Abstract
Benign Prostatic Hyperplasia (BPH) affects, worldwide, 50% of 60-year-old men. The Peruvian plant red maca (Lepidium meyenii) inhibits BPH in rodents. This study aimed to determine the effects of methanolic red maca extract and its n-butanol and aqueous fractions on expression of androgen and oestrogen receptors in rats with testosterone enanthate-induced BPH. Thirty-six rats in six groups were studied. Control group received 2 mL of vehicle orally and 0.1 mL of propylene glycol intramuscularly. The second group received vehicle orally and testosterone enanthate (TE) (25 mg/0.1 mL) intramuscularly in days 1 and 7. The other four groups were BPH-induced with TE and received, during 21 days, 3.78 mg/mL of finasteride, 18.3 mg/mL methanol extract of red maca, 2 mg/mL of n-butanol fraction, or 16.3 mg/mL of aqueous fraction from red maca. Treatments with red maca extract and its n-butanol but not aqueous fraction reduced prostate weight similar to finasteride. All maca treated groups restored the expression of ERβ, but only the aqueous fraction increased androgen receptors and ERα. In conclusion, butanol fraction of red maca reduced prostate size in BPH by restoring expression of ERβ without affecting androgen receptors and ERα. This effect was not observed with aqueous fraction of methanolic extract of red maca.
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Lee PG, Kim J, Kim EJ, Lee SH, Choi KY, Kazlauskas RJ, Kim BG. Biosynthesis of (-)-5-Hydroxy-equol and 5-Hydroxy-dehydroequol from Soy Isoflavone, Genistein Using Microbial Whole Cell Bioconversion. ACS Chem Biol 2017; 12:2883-2890. [PMID: 28985044 DOI: 10.1021/acschembio.7b00624] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Equols are isoflavandiols formed by reduction of soy isoflavones such as daidzein and genistein by gut microorganisms. These phytoestrogens are of interest for their various biological effects. We report biosynthesis from genistein to (-)-5-hydroxy-equol in recombinant E. coli expressing three reductases (daidzein reductase DZNR, dihidrodaidzein reductase DHDR, tetrahydrodaidzein reductase THDR) and a racemase (dihydrodaidzein racemase, DDRC) originating from the gut bacterium, Slackia isoflavoniconvertens. The biosynthesized 5-hydroxy-equol proved as an optically negative enantiomer, nonetheless it displayed an inverse circular dichroism spectrum to (S)-equol. Compartmentalized expression of DZNR and DDRC in one E. coli strain and DHDR and THDR in another increased the yield to 230 mg/L and the productivity to 38 mg/L/h. If the last reductase was missing, the intermediate spontaneously dehydrated to 5-hydroxy-dehydroequol in up to 99 mg/L yield. This novel isoflavene, previously not known to be synthesized in nature, was also detected in this biotransformation system. Although (S)-equol favors binding to human estrogen receptor (hER) β over hERα, (-)-5-hydroxy-equol showed the opposite preference. This study provides elucidation of the biosynthetic route of (-)-5-hydroxy-equol and measurement of its potent antagonistic character as a phytoestrogen for the first time.
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Affiliation(s)
- Pyung-Gang Lee
- School of Chemical
and Biological Engineering, Institute of Engineering Research, Seoul National University, Seoul, Republic of Korea
- Institute
of Molecular Biology and Genetics, Seoul National University, Seoul, Republic of Korea
| | - Joonwon Kim
- School of Chemical
and Biological Engineering, Institute of Engineering Research, Seoul National University, Seoul, Republic of Korea
- Institute
of Molecular Biology and Genetics, Seoul National University, Seoul, Republic of Korea
| | - Eun-Jung Kim
- Institute
of Molecular Biology and Genetics, Seoul National University, Seoul, Republic of Korea
| | - Sang-Hyuk Lee
- School of Chemical
and Biological Engineering, Institute of Engineering Research, Seoul National University, Seoul, Republic of Korea
- Institute
of Molecular Biology and Genetics, Seoul National University, Seoul, Republic of Korea
| | - Kwon-Young Choi
- Department of Environmental
Engineering, College of Engineering, Ajou University, Suwon, Republic of Korea
| | - Romas J. Kazlauskas
- Department of Biochemistry, Molecular Biology & Biophysics and The Biotechnology Institute, University of Minnesota, Saint Paul, Minnesota 55108, United States
| | - Byung-Gee Kim
- School of Chemical
and Biological Engineering, Institute of Engineering Research, Seoul National University, Seoul, Republic of Korea
- Institute
of Molecular Biology and Genetics, Seoul National University, Seoul, Republic of Korea
- Institute
of Bioengineering, Seoul National University, Seoul, Republic of Korea
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Lephart ED. Resveratrol, 4' Acetoxy Resveratrol, R-equol, Racemic Equol or S-equol as Cosmeceuticals to Improve Dermal Health. Int J Mol Sci 2017; 18:ijms18061193. [PMID: 28587197 PMCID: PMC5486016 DOI: 10.3390/ijms18061193] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Revised: 05/31/2017] [Accepted: 05/31/2017] [Indexed: 12/22/2022] Open
Abstract
Phytochemicals are botanical compounds used in dermatology applications as cosmeceuticals to improve skin health. Resveratrol and equol are two of the best-known polyphenolic or phytoestrogens having similar chemical structures and some overlapping biological functions to 17β-estradiol. Human skin gene expression was reviewed for 28 different biomarkers when resveratrol, 4′ acetoxy resveratrol (4AR), R-equol, racemic equol or S-equol were tested. Sirtuin 1 activator (SIRT 1) was stimulated by resveratrol and 4AR only. Resveratrol, R-equol and racemic equol were effective on the aging biomarkers proliferating cell nuclear factor (PCNA), nerve growth factor (NGF), 5α-reductase and the calcium binding proteins S100 A8 and A9. Racemic equol and 4AR displayed among the highest levels for the collagens, elastin and tissue inhibitor of the matrix metalloproteinase 1 (TIMP 1). S-equol displayed the lowest level of effectiveness compared to the other compounds. The 4AR analog was more effective compared to resveratrol by 1.6-fold. R-equol and racemic equol were almost equal in potency displaying greater inhibition vs. resveratrol or its 4′ analog for the matrix metalloproteinases (MMPs), but among the inflammatory biomarkers, resveratrol, 4AR, R-equol and racemic equol displayed high inhibition. Thus, these cosmeceuticals display promise to improve dermal health; however, further study is warranted to understand how phytochemicals protect/enhance the skin.
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Affiliation(s)
- Edwin D Lephart
- Department of Physiology and Developmental Biology and The Neuroscience Center, LS 4005, College of Life Sciences, Brigham Young University, Provo, UT 84602, USA.
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Asiedu B, Anang Y, Nyarko A, Doku DA, Amoah BY, Santa S, Ngala RA, Asare GA. The role of sex steroid hormones in benign prostatic hyperplasia. Aging Male 2017; 20:17-22. [PMID: 28084142 DOI: 10.1080/13685538.2016.1272101] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
INTRODUCTION The etiology of benign prostatic hyperplasia (BPH) remains a mystery to scientists; estrogen/androgen imbalance in aged men has been implicated. METHODS Thirty (30) apparently healthy men and newly diagnosed BPH patients were recruited from the Ghana Police Hospital. Lower urinary tract syndrome (LUTS) and prostate volume were assessed via the prostate symptom score sheet (IPSS) and abdominopelvic scan, respectively. Laboratory assays for total prostate specific antigen (tPSA) and hormones [androstenedione (AED), testosterone (T), dihydrotestosterone (DHT), androstanedioladiol (3α-adiol), androstanediol (3β-diol), estrone (E1) and estradiol (E2)] were performed via ELISA techniques. Non-parametric analyses were employed. p < 0.05 was considered significant. RESULTS AED was significantly higher in controls compared to the BPH patients. AKRIC2 (3α-diol/DHT) was significantly higher in the BPH group (p < 0.001) whiles AKRIC1 (3β-diol/DHT) was significantly lower. Estradiol was significantly higher in BPH (p= 0.029). Age correlated negatively with T, while a negative correlation was observed between TIPSS and 3β-diol and AKRIC1. Also, prostate volume correlated negatively with fT.tPSA correlated positively with E2 and aromatase activity (E2/T) and negatively with fT. On multiple linear regression, DHT and 3β-diol remained independent predictors for TIPSS and fT for tPSA. CONCLUSION Estrogens and androstanediols seem to play a role in BPH development.
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Affiliation(s)
- Bernice Asiedu
- a Department of Medical Laboratory Sciences , University of Ghana School of Biomedical and Allied Health Sciences , Korle Bu , Accra , Ghana and
| | - Yvonne Anang
- a Department of Medical Laboratory Sciences , University of Ghana School of Biomedical and Allied Health Sciences , Korle Bu , Accra , Ghana and
| | - Adraina Nyarko
- b Department of Molecular Medicine , Kwame Nkrumah University of Science and Technology , Kumasi , Ghana
| | - Derek Amartey Doku
- a Department of Medical Laboratory Sciences , University of Ghana School of Biomedical and Allied Health Sciences , Korle Bu , Accra , Ghana and
| | - Brodrick Y Amoah
- a Department of Medical Laboratory Sciences , University of Ghana School of Biomedical and Allied Health Sciences , Korle Bu , Accra , Ghana and
| | - Sheila Santa
- a Department of Medical Laboratory Sciences , University of Ghana School of Biomedical and Allied Health Sciences , Korle Bu , Accra , Ghana and
| | - Robert A Ngala
- b Department of Molecular Medicine , Kwame Nkrumah University of Science and Technology , Kumasi , Ghana
| | - George A Asare
- a Department of Medical Laboratory Sciences , University of Ghana School of Biomedical and Allied Health Sciences , Korle Bu , Accra , Ghana and
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Eleazu C, Eleazu K, Kalu W. Management of Benign Prostatic Hyperplasia: Could Dietary Polyphenols Be an Alternative to Existing Therapies? Front Pharmacol 2017; 8:234. [PMID: 28503148 PMCID: PMC5408066 DOI: 10.3389/fphar.2017.00234] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 04/12/2017] [Indexed: 02/05/2023] Open
Abstract
The incidence of benign prostatic hyperplasia (BPH) is gradually on the increase. While conventional drugs such as the α1-adrenergic receptor antagonists and 5α-reductase inhibitors have been found to be useful in the treatment of BPH, the adverse side effects associated with their usage, have led to increased search for alternative means of managing this disease. Furthermore, although surgery has also been suggested to be a sure method, the cost and risks associated with it excludes it as a routine treatment. Dietary polyphenols have gained public interest in recent times due to their roles in the prevention of various diseases that implicate free radicals/reactive oxygen species. However, their roles in the management of BPH have not been explored. Hence, this review on their prospects in the management of BPH and their mechanisms of action. Literature search was carried out in several electronic data bases such as PubMed, Google Scholar, Medline, Agora, and Hinari from1970 to 2017 to identify the current status of knowledge on this concept. The findings from these data bases suggest that while dietary polyphenols may not replace the need for the existing therapies in the management of BPH, they hold promise in BPH management which could be explored by researchers working in this field.
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Affiliation(s)
- Chinedum Eleazu
- Department of Chemistry/Biochemistry, Federal University Ndufu-Alike, IkwoAbakaliki, Nigeria
- *Correspondence: Chinedum Eleazu,
| | - Kate Eleazu
- Department of Biochemistry, Ebonyi State UniversityAbakaliki, Nigeria
| | - Winner Kalu
- Department of Biochemistry, Michael Okpara University of AgricultureUmudike, Nigeria
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Garg S, Lule VK, Malik RK, Tomar SK. Soy Bioactive Components in Functional Perspective: A Review. INTERNATIONAL JOURNAL OF FOOD PROPERTIES 2016. [DOI: 10.1080/10942912.2015.1136936] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Sheenam Garg
- Dairy Microbiology Division, National Dairy Research Institute, Karnal, Haryana, India
| | - Vaibhao Kisanrao Lule
- Dairy Microbiology Division, National Dairy Research Institute, Karnal, Haryana, India
| | - Ravinder Kumar Malik
- Dairy Microbiology Division, National Dairy Research Institute, Karnal, Haryana, India
| | - Sudhir Kumar Tomar
- Dairy Microbiology Division, National Dairy Research Institute, Karnal, Haryana, India
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Modulation of Aromatase by Phytoestrogens. Enzyme Res 2015; 2015:594656. [PMID: 26798508 PMCID: PMC4699002 DOI: 10.1155/2015/594656] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 10/31/2015] [Accepted: 11/17/2015] [Indexed: 12/29/2022] Open
Abstract
The aromatase enzyme catalyzes the conversion of androgens to estrogens in many human tissues. Estrogens are known to stimulate cellular proliferation associated with certain cancers and protect against adverse symptoms during the peri- and postmenopausal intervals. Phytoestrogens are a group of plant derived naturally occurring compounds that have chemical structures similar to estrogen. Since phytoestrogens are known to be constituents of animal/human food sources, these compounds have received increased research attention. Phytoestrogens may contribute to decreased cancer risk by the inhibition of aromatase enzyme activity and CYP19 gene expression in human tissues. This review covers (a) the aromatase enzyme (historical descriptions on function, activity, and gene characteristics), (b) phytoestrogens in their classifications and applications to human health, and (c) a chronological coverage of aromatase activity modulated by phytoestrogens from the early 1980s to 2015. In general, phytoestrogens act as aromatase inhibitors by (a) decreasing aromatase gene expression, (b) inhibiting the aromatase enzyme itself, or (c) in some cases acting at both levels of regulation. The findings presented herein are consistent with estrogen's impact on health and phytoestrogen's potential as anticancer treatments, but well-controlled, large-scale studies are warranted to determine the effectiveness of phytoestrogens on breast cancer and age-related diseases.
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