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Validation of ELISAs for Isoflavones and Enterolactone for Phytoestrogen Intake Assessment in the French Population. Nutrients 2023; 15:nu15040967. [PMID: 36839324 PMCID: PMC9967075 DOI: 10.3390/nu15040967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 02/07/2023] [Accepted: 02/09/2023] [Indexed: 02/17/2023] Open
Abstract
Phytoestrogens are dietary compounds with low estrogenic activity. The two main categories in the French diet are isoflavones from pulses and enterolignans metabolized by the gut flora from various lignans found in fruits, vegetables, grains, and beverages. Isoflavones and lignans have different effects on human physiology and can antagonize each other. Comprehensive lists of phytoestrogen sources were constructed based on measurements and literature data. The 24 h and 48 h dietary recalls were proposed to the volunteers of the ISOLED cohort (NCT03421184). Urine and plasma samples from these volunteers were assayed for genistein, daidzein, equol, and enterolactone. A dietary score was constructed considering the pharmacokinetic characteristics of these compounds. Correlation analyses were applied to fluid concentrations associated with dietary scores. Pearson correlations reached 0.921 (p < 0.001) for urineIF, 0.900 (p < 0.001) for plasmaIF, 0.764 (p < 0.001) for urineENL, and 0.723 (p < 0.001) for plasmaENL. ELISAs associated with careful intake assessments proved to be good tools for phytoestrogens' exposure estimation.
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Barzani H, Ali H, Şahin C, Kıran M, Yardım Y. A new approach for the voltammetric sensing of the phytoestrogen genistein in the urine samples at a non‐modified boron‐doped diamond electrode. ELECTROANAL 2022. [DOI: 10.1002/elan.202100608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Fujitani T, Fujii Y, Lyu Z, Harada Sassa M, Harada KH. Urinary equol levels are positively associated with urinary estradiol excretion in women. Sci Rep 2021; 11:19532. [PMID: 34593903 PMCID: PMC8484452 DOI: 10.1038/s41598-021-98872-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 09/16/2021] [Indexed: 11/09/2022] Open
Abstract
Isoflavones found in soy products are a promising class of nutrients that may have a positive effect on human health. In particular, the phytoestrogen metabolite equol is associated with a reduced risk of developing female hormone-related diseases. However, the effect of equol on estrogen remains unclear. Equol can modify blood and urinary estradiol (E2) levels. The aim of this cross-sectional study was to examine the associations between urinary estrogen levels, equol levels, and equol production status in Japanese women. We analyzed urine samples from 520 women by gas chromatography-mass spectrometry. Urinary E2 and 4-hydroxylated E2 levels were higher in equol producers (EQP) than in non-EQPs (P < 0.0001 and P=0.00112, respectively). After adjusting for age and tobacco use by analysis of covariance, the association remained significant (β = 0.299, P < 0.0001). Analysis of covariance demonstrated that equol levels in urine were also positively associated with urinary E2 (β = 0.597, P < 0.0001). The log equol concentration showed a significant, but moderate, negative association with the serum E2 concentration (β = − 0.0225, P = 0.0462). Our findings suggest that equol may promote urinary E2 excretion and modify blood E2 levels in women.
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Affiliation(s)
- Tomoko Fujitani
- Department of Health and Environmental Sciences, Kyoto University Graduate School of Medicine, Kyoto, 606-8501, Japan
| | - Yukiko Fujii
- Department of Pharmaceutical Sciences, Daiichi University of Pharmacy, Fukuoka, 815-8511, Japan
| | - Zhaoqing Lyu
- Department of Health and Environmental Sciences, Kyoto University Graduate School of Medicine, Kyoto, 606-8501, Japan
| | - Mariko Harada Sassa
- Department of Health and Environmental Sciences, Kyoto University Graduate School of Medicine, Kyoto, 606-8501, Japan
| | - Kouji H Harada
- Department of Health and Environmental Sciences, Kyoto University Graduate School of Medicine, Kyoto, 606-8501, Japan.
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Chiba T, Nagai T, Kohda F, Nakahara T, Kono M. The Connection between Urinary Equol Levels and the Prevalence of Atopic Dermatitis. Int Arch Allergy Immunol 2020; 182:32-38. [PMID: 32932251 DOI: 10.1159/000510119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 07/10/2020] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Soy isoflavones and their metabolites such as equol have been associated with a reduced risk of hormone-sensitive tumors and metabolic syndromes. However, individual soy isoflavones and equol levels in atopic dermatitis remain uninvestigated. OBJECTIVE The aim of this study is to compare the levels of urinary daidzein, genistein, and equol between atopic dermatitis patients and normal subjects and to examine the correlation between equol concentration and the severity of clinical symptoms. METHODS A cross-sectional study was conducted at Akita University Hospital and Aso Iizuka Hospital in Japan. Fifty patients with confirmed atopic dermatitis diagnosis and 67 healthy controls were recruited. Daidzein, genistein, and equol in urine were measured by using a high-performance liquid chromatography-mass spectrometry system. RESULTS Urinary equol levels were significantly lower in the atopic dermatitis patients than in the healthy controls (p = 0.002). The difference was particularly noticeable in young people (6-19 years, p < 0.001). No correlations were found between urinary equol levels and the severity of clinical symptoms and laboratory data in the atopic dermatitis patients. CONCLUSION Equol levels in childhood might be involved in the development of atopic dermatitis.
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Affiliation(s)
- Takahito Chiba
- Department of Dermatology and Plastic Surgery, Akita University Graduate School of Medicine, Akita, Japan,
| | - Takuya Nagai
- Department of Dermatology and Plastic Surgery, Akita University Graduate School of Medicine, Akita, Japan
| | - Futoshi Kohda
- Department of Dermatology, Aso Iizuka Hospital, Fukuoka, Japan
| | - Takeshi Nakahara
- Department of Dermatology, Kyushu University School of Medicine, Fukuoka, Japan
| | - Michihiro Kono
- Department of Dermatology and Plastic Surgery, Akita University Graduate School of Medicine, Akita, Japan
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Yusakul G, Sakamoto S, Juengwatanatrakul T, Putalun W, Tanaka H, Morimoto S. Preparation and application of a monoclonal antibody against the isoflavone glycoside daidzin using a mannich reaction-derived hapten conjugate. PHYTOCHEMICAL ANALYSIS : PCA 2016; 27:81-8. [PMID: 26689919 DOI: 10.1002/pca.2604] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 10/18/2015] [Accepted: 10/19/2015] [Indexed: 06/05/2023]
Abstract
INTRODUCTION Daidzin and its aglycone daidzein are major pharmacologically active compounds of soybean (Glycine max), kudzu (Pueraria lobata), and kwao kruea khao (P. mirifica). Pharmacological activities of daidzin are mediated by its more potent metabolites daidzein and equol; however, daidzin is the predominant compound found in these medicinal plants, and the efficacy and safety of equol depend on the amount of daidzin consumed. OBJECTIVE To develop a specific monoclonal antibody (MAb)-based indirect competitive enzyme-linked immunosorbent assay (icELISA) for standardisation of daidzin content in herbal medicines or nutraceuticals. METHODOLOGY The Mannich reaction was used for the synthesis of a highly immunogenic conjugate between daidzin and a cationised carrier protein. Splenocytes of hyperimmunised mice were fused with myeloma cells to generate a hybridoma secreting antibody against daidzin. RESULTS The icELISA showed high selectivity and acceptable sensitivity for daidzin determination (1.56-100 ng/mL) with high reproducibility (coefficients of variation were < 5%). The icELISA was a reliable analytical method for daidzin in Glycine max, Pueraria lobata and P. mirifica, for which daidzin recoveries from spiked samples were 98.99-104.94%. Daidzin content of these plant-derived products determined using the icELISA were in close agreement with those determined by a HPLC-UV method. CONCLUSION The icELISA is useful for specific daidzin determination because of its reliability, low cost, speed and high throughput.
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Affiliation(s)
- Gorawit Yusakul
- Department of Pharmacognosy, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Seiichi Sakamoto
- Department of Pharmacognosy, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | | | - Waraporn Putalun
- Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Hiroyuki Tanaka
- Department of Pharmacognosy, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Satoshi Morimoto
- Department of Pharmacognosy, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
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Affiliation(s)
- Shigeto Uchiyama
- Otsuka Pharmaceutical Co., Ltd., Saga Nutraceuticals Research Institute
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Jenkins G, Wainwright LJ, Holland R, Barrett KE, Casey J. Wrinkle reduction in post-menopausal women consuming a novel oral supplement: a double-blind placebo-controlled randomized study. Int J Cosmet Sci 2013; 36:22-31. [PMID: 23927381 PMCID: PMC4265247 DOI: 10.1111/ics.12087] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 07/28/2013] [Indexed: 12/11/2022]
Abstract
Objective The maintenance of youthful skin appearance is strongly desired by a large proportion of the world's population. The aim of the present study was therefore to evaluate the effect on skin wrinkling, of a combination of ingredients reported to influence key factors involved in skin ageing, namely inflammation, collagen synthesis and oxidative/UV stress. A supplemented drink was developed containing soy isoflavones, lycopene, vitamin C and vitamin E and given to post-menopausal women with a capsule containing fish oil. Method We have performed a double-blind randomized controlled human clinical study to assess whether this cocktail of dietary ingredients can significantly improve the appearance of facial wrinkles. Results We have shown that this unique combination of micronutrients can significantly reduce the depth of facial wrinkles and that this improvement is associated with increased deposition of new collagen fibres in the dermis. Conclusion This study demonstrates that consumption of a mixture of soy isoflavones, lycopene, vitamin C, vitamin E and fish oil is able to induce a clinically measureable improvement in the depth of facial wrinkles following long-term use. We have also shown, for the first time with an oral product, that the improvement is associated with increased deposition of new collagen fibres in the dermis. Résumé
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Affiliation(s)
- G Jenkins
- Unilever R&D, Colworth Discover, Colworth Science Park, Sharnbrook, Bedfordshire, MK44 1LQ, U.K
| | - L J Wainwright
- Unilever R&D, Colworth Discover, Colworth Science Park, Sharnbrook, Bedfordshire, MK44 1LQ, U.K
| | - R Holland
- Unilever R&D, Colworth Discover, Colworth Science Park, Sharnbrook, Bedfordshire, MK44 1LQ, U.K
| | - K E Barrett
- Unilever R&D, Colworth Discover, Colworth Science Park, Sharnbrook, Bedfordshire, MK44 1LQ, U.K
| | - J Casey
- Unilever R&D, Colworth Discover, Colworth Science Park, Sharnbrook, Bedfordshire, MK44 1LQ, U.K
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Minekawa T, Kambegawa A, Shindome K, Ohkuma H, Abe K, Maekawa H, Arakawa H. Development of bioluminescent enzyme immunoassay for s-equol using firefly luciferase and its application to the assessment of equol-producer status. Chem Pharm Bull (Tokyo) 2011; 59:84-7. [PMID: 21212552 DOI: 10.1248/cpb.59.84] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In this study, we developed a specific bioluminescent enzyme immunoassay (BLEIA) for S-equol, employing firefly luciferase as a labeling enzyme, as an alternative to HPLC methods. Satisfactory correlation (r=0.992) was shown when this S-equol BLEIA was compared with HPLC. The cross-reactivity with R-equol as its diastereoisomer is <5%, and that with daidzein, which is the substrate of equol, is 0.02%. Frequencies of Japanese equol producers determined using two distinct approaches were compared: a threshold value for urinary S-equol concentration of 232 ng/ml gave frequencies of 32% of men and 19% of women. These values correspond to the results for log(10)-transformed urinary S-equol to daidzein ratio threshold of -1.75, namely, 34% of men and 19% of women. When the changes in concentration of urinary equol and daidzein were measured after ingestion of isoflavone, the maximum concentration (C(max)) of urinary equol appeared after 9.6 h of isoflavone consumption; this C(max) was 2 h later than that for daidzein. The S-equol BLEIA documented in this study is expected to be an important tool for the assessment of equol producer status and demonstration of the bioavailability of isoflavone.
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Affiliation(s)
- Takayuki Minekawa
- Biochemical Research Laboratory, Eiken Chemical Co., Ltd., Shimotsuga-gun, Tochigi, Japan.
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Degen GH, Blaszkewicz M, Shi L, Buyken AE, Remer T. Urinary isoflavone phytoestrogens in German children and adolescents--a longitudinal examination in the DONALD cohort. Mol Nutr Food Res 2011; 55:359-67. [PMID: 20938994 DOI: 10.1002/mnfr.201000325] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Revised: 08/26/2010] [Accepted: 08/30/2010] [Indexed: 12/16/2023]
Abstract
SCOPE In light of concerns about hormonally active agents, it is important to assess human exposure to such compounds, especially in children as a susceptible subgroup. Estrogenic plant constituents are present in the human diet in varying levels, in particular the isoflavones daidzein (DAI) and genistein (GEN). We aimed to examine age-dependent and secular trends in phytoestrogen exposures and to investigate equol (EQ) excretion of German children using biomarker analysis in 24-h urine samples from a longitudinally designed study. METHODS AND RESULTS The concentrations of DAI, its metabolite EQ and GEN were determined by GC-MS analysis in 24-h urines (510 samples) collected between 1985 and 2000 in 90 (47 boys) German children (6-18 years old), who are participants in the Dortmund Nutritional and Anthropometric Longitudinally Designed study. The results from the urinary biomarker analysis indicate isoflavone exposures at quite variable levels in German children: Analyte concentrations in over 500 urine samples cover the range reported previously in adults on typical German diet and with soy intake. EQ, the DAI metabolite produced by the gastrointestinal microflora, was detected in a high fraction of all samples, with 28/90 children (31%) excreting EQ in all their urines, and 62/90 children (68%) in at least one sample. Interestingly, when multiple urines obtained from individuals at different ages (6-18 years) were analyzed, EQ formation did not appear to be a constant trait over time. When stratified by sex, DAI, EQ and GEN concentrations (ng/mL) in urines and excretion rates (μg/day) were similar in boys and girls. Total isoflavone excretion rates (μg/day) increased during childhood (6-12 years) (p=0.02) and were constant during adolescence (13-18 years) (p=0.6). No clear trend for changes in dietary isoflavone exposure over the total study period was seen (p=0.7). CONCLUSIONS In conclusion, biomarkers in urine of German children and adolescents indicate a frequent, but widely variable dietary isoflavone intake and suggest no secular increase (1985-2000) in the exposure to isoflavone phytoestrogens among German children and adolescents.
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Affiliation(s)
- Gisela H Degen
- IfADo--Leibniz Research Centre for Working Environment and Human Factors at the TU Dortmund, Germany.
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Yang Z, Zhu W, Gao S, Xu H, Wu B, Kulkarni K, Singh R, Tang L, Hu M. Simultaneous determination of genistein and its four phase II metabolites in blood by a sensitive and robust UPLC-MS/MS method: Application to an oral bioavailability study of genistein in mice. J Pharm Biomed Anal 2010; 53:81-9. [PMID: 20378296 DOI: 10.1016/j.jpba.2010.03.011] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 02/07/2010] [Accepted: 03/08/2010] [Indexed: 11/26/2022]
Abstract
The purpose of this research was to develop a sensitive and reproducible UPLC-MS/MS method to simultaneously quantify genistein, genistein-7-O-glucuronide (G-7-G), genistein-4'-O-glucuronide (G-4'-G), genistein-4'-O-sulfate (G-4'-S) and genistein-7-O-sulfate (G-7-S) in mouse blood samples. After the method was fully validated over a wide linear range, it was applied to quantify the levels of genistein and its metabolites in a mouse bioavailability study. The linear response range was 19.5-10,000 nM for genistein, 12.5-3200 nM for G-7-G, 20-1280 nM for G-4'-G, 1.95-2000 nM for G-4'-S, and 1.56-3200 nM for G-7-S, respectively. The lower limit of quantification (LLOQ) was 4.88, 6.25, 5, 0.98 and 0.78 nM for genistein, G-7-G, G-4'-G, G-4'-S and G-7-S, respectively. Only 20 microl mouse blood sample from i.v. and p.o. administration were needed for analysis because of the high sensitivity of the method. The intra- and inter-day variance is less than 15% and accuracy is within 85-115%. The analysis was finished within 4.5 min. The applicability of this assay was demonstrated and successfully applied for bioavailability study in FVB mouse after i.v. and p.o. administration of 20mg/kg of genistein, and its oral bioavailability was approximately 23.4%.
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Affiliation(s)
- Zhen Yang
- Department of Pharmacological and Pharmaceutical Science, College of Pharmacy, University of Houston, 1441 Moursund Street, Houston, TX 77030, USA
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Phenolics: occurrence and immunochemical detection in environment and food. Molecules 2009; 14:439-73. [PMID: 19158655 PMCID: PMC6253769 DOI: 10.3390/molecules14010439] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2008] [Revised: 01/06/2009] [Accepted: 01/12/2009] [Indexed: 11/24/2022] Open
Abstract
Phenolic compounds may be of natural or anthropogenic origin and be present in the environment as well as in food. They comprise a large and diverse group of compounds that may be either beneficial or harmful for consumers. In this review first a non-exhausting overview of interesting phenolics is given, in particular with regards to their presence in environment and food. For some of these compounds, beneficial, toxicological and/or optionally endocrine disrupting activities will be presented. Further, immunochemical detection and/or isolation methods developed will be discussed, including advantages and disadvantages thereof in comparison with conventional analytical methods such as HPLC, GC, MS. A short overview of new sensor-like methods will also be included for present and future application.
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Hall WL, Formanuik NL, Harnpanich D, Cheung M, Talbot D, Chowienczyk PJ, Sanders TAB. A meal enriched with soy isoflavones increases nitric oxide-mediated vasodilation in healthy postmenopausal women. J Nutr 2008; 138:1288-92. [PMID: 18567749 DOI: 10.1093/jn/138.7.1288] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Evidence from infusion studies suggests that soy isoflavones influence nitric oxide-dependent vasorelaxation. It is uncertain whether orally consumed isoflavones have similar effects. Healthy postmenopausal women (n = 22) consumed 2 low-fat test meals in random order 1 wk apart, with 80 mg isoflavones (ISO) or without isoflavones (CON). Endothelium-dependent vasodilation, assessed by brachial artery flow-mediated dilatation (FMD), was measured in fasting subjects, and 4 and 6 h following the test meal, in addition to blood pressure and pulse wave analysis to derive the peripheral augmentation index (pAIx). Blood samples were taken after fasting, and 5 and 7 h following the test meal for serum isoflavone, plasma 8-isoprostane F(2alpha), nitric oxide metabolites (NOx), glucose, and triacylglycerol analysis. Serum genistein and daidzein concentrations (geometric mean, 95% CI) reached 1.49 (1.20-1.84) micromol/L and 0.95 (0.70-1.30) micromol/L, respectively, following ISO (7 h). FMD and plasma NOx concentrations were greater following ISO compared with CON, indicating better postprandial endothelial function. FMD values (%, mean +/- SD) were: CON, 5.49 +/- 2.32, 4.35 +/- 2.32, 4.40 +/- 2.26; ISO, 5.38 +/- 1.91, 5.08 +/- 1.74, 6.11 +/- 2.60, at baseline, 4 h, and 6 h, respectively (P < 0.01). Plasma NOx concentrations (micromol/L, mean +/- SD) were: CON, 20.0 +/- 5.1, 16.8 +/- 5.1, 23.1 +/- 6.0; ISO, 18.6 +/- 6.3, 19.5 +/- 5.1, 21.3 +/- 10.1, at baseline, 5 h, and 7 h, respectively (P < 0.005). Treatment did not affect pAIx, blood pressure, or plasma 8-isoprostane F(2alpha) concentrations. In conclusion, consuming an isoflavone-enriched low-fat meal acutely increases endothelium-dependent vasodilation in postmenopausal women. Regular consumption of soy isoflavones may protect against endothelial dysfunction.
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Affiliation(s)
- Wendy L Hall
- Nutritional Sciences Division, School of Biomedical and Health Sciences, King's College London, London SE1 9NH, UK.
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Vacek J, Klejdus B, Lojková L, Kubán V. Current trends in isolation, separation, determination and identification of isoflavones: A review. J Sep Sci 2008; 31:2054-67. [DOI: 10.1002/jssc.200700569] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Dentith S, Lockwood B. Development of techniques for the analysis of isoflavones in soy foods and nutraceuticals. Curr Opin Clin Nutr Metab Care 2008; 11:242-7. [PMID: 18403919 DOI: 10.1097/mco.0b013e3282fa15c9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
PURPOSE OF REVIEW For over 20 years, soy isoflavones have been investigated for their ability to prevent a wide range of cancers and cardiovascular problems, and numerous other disease states. This research is underpinned by the ability of researchers to analyse isoflavones in various forms in a range of raw materials and biological fluids. This review summarizes the techniques recently used in their analysis. RECENT FINDINGS The speed of high performance liquid chromatography analysis has been improved, allowing analysis of more samples, and increasing the sensitivity of detection techniques allows quantification of isoflavones down to nanomoles per litre levels in biological fluids. The combination of high-performance liquid chromatography with immunoassay has allowed identification and estimation of low-level soy isoflavones. The use of soy isoflavone supplements has shown an increase in their circulating levels in plasma and urine, aiding investigation of their biological effects. The significance of the metabolite equol has spurned research into new areas, and recently the specific enantiomers have been studied. SUMMARY High-performance liquid chromatography, capillary electrophoresis and gas chromatography are widely used with a range of detection systems. Increasingly, immunoassay is being used because of its high sensitivity and low cost.
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Affiliation(s)
- Susan Dentith
- University of Manchester, School of Pharmacy and Pharmaceutical Sciences, Manchester, UK
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Current awareness in phytochemical analysis. PHYTOCHEMICAL ANALYSIS : PCA 2008; 19:91-98. [PMID: 18340659 DOI: 10.1002/pca.1036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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