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Sasikumar K, Rajamanikandan R, Ju H. Nitrogen- and Sulfur-Codoped Strong Green Fluorescent Carbon Dots for the Highly Specific Quantification of Quercetin in Food Samples. MATERIALS (BASEL, SWITZERLAND) 2023; 16:7686. [PMID: 38138829 PMCID: PMC10744681 DOI: 10.3390/ma16247686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Revised: 12/14/2023] [Accepted: 12/15/2023] [Indexed: 12/24/2023]
Abstract
Carbon dots (CDs) doped with heteroatoms have garnered significant interest due to their chemically modifiable luminescence properties. Herein, nitrogen- and sulfur-codoped carbon dots (NS-CDs) were successfully prepared using p-phenylenediamine and thioacetamide via a facile process. The as-developed NS-CDs had high photostability against photobleaching, good water dispersibility, and excitation-independent spectral emission properties due to the abundant amino and sulfur functional groups on their surface. The wine-red-colored NS-CDs exhibited strong green emission with a large Stokes shift of up to 125 nm upon the excitation wavelength of 375 nm, with a high quantum yield (QY) of 28%. The novel NS-CDs revealed excellent sensitivity for quercetin (QT) detection via the fluorescence quenching effect, with a low detection limit of 17.3 nM within the linear range of 0-29.7 μM. The fluorescence was quenched only when QT was brought near the NS-CDs. This QT-induced quenching occurred through the strong inner filter effect (IFE) and the complex bound state formed between the ground-state QT and excited-state NS-CDs. The quenching-based detection strategies also demonstrated good specificity for QT over various interferents (phenols, biomolecules, amino acids, metal ions, and flavonoids). Moreover, this approach could be effectively applied to the quantitative detection of QT (with good sensing recovery) in real food samples such as red wine and onion samples. The present work, consequently, suggests that NS-CDs may open the door to the sensitive and specific detection of QT in food samples in a cost-effective and straightforward manner.
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Affiliation(s)
| | | | - Heongkyu Ju
- Department of Physics, Gachon University, Seongnam-si 13120, Gyeonggi-do, Republic of Korea; (K.S.); (R.R.)
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2
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Dadge SD, Syed AA, Husain A, Valicherla GR, Gayen JR. Simultaneous Estimation of Quercetin and trans-Resveratrol in Cissus quadrangularis Extract in Rat Serum Using Validated LC-MS/MS Method: Application to Pharmacokinetic and Stability Studies. Molecules 2023; 28:4656. [PMID: 37375211 DOI: 10.3390/molecules28124656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 05/19/2023] [Accepted: 06/01/2023] [Indexed: 06/29/2023] Open
Abstract
Cissus quadrangularis is a nutrient-rich plant with a history of use in traditional medicine. It boasts a diverse range of polyphenols, including quercetin, resveratrol, β-sitosterol, myricetin, and other compounds. We developed and validated a sensitive LC-MS/MS method to quantify quercetin and t-res biomarkers in rat serum and applied this method to pharmacokinetic and stability studies. The mass spectrometer was set to negative ionization mode for the quantification of quercetin and t-res. Phenomenex Luna (C18(2), 100 A, 75 × 4.6 mm, 3 µ) column was utilized to separate the analytes using an isocratic mobile phase consisting of methanol and 0.1% formic acid in water (82:18). Validation of the method was performed using various parameters, including linearity, specificity, accuracy, stability, intra-day, inter-day precision, and the matrix effect. There was no observed significant endogenous interference from the blank serum. The analysis was completed within 5.0 min for each run, and the lower limit of quantification was 5 ng/mL. The calibration curves showed a linear range with a high correlation coefficient (r2 > 0.99). The precision for intra- and inter-day assays showed relative standard deviations from 3.32% to 8.86% and 4.35% to 9.61%, respectively. The analytes in rat serum were stable during bench-top, freeze-thaw, and autosampler (-4 °C) stability studies. After oral administration, the analytes showed rapid absorption but underwent metabolism in rat liver microsomes despite being stable in simulated gastric and intestinal fluids. Intragastric administration resulted in higher absorption of quercetin and t-res, with greater Cmax, shorter half-life, and improved elimination. No prior research has been conducted on the oral pharmacokinetics and stability of anti-diabetic compounds in the Ethanolic extract of Cissus quadrangularis EECQ, making this the first report. Our findings can provide the knowledge of EECQ's bioanalysis and pharmacokinetic properties which is useful for future clinical trials.
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Affiliation(s)
- Shailesh D Dadge
- Pharmaceutics & Pharmacokinetics Division, CSIR-Central Drug Research Institute (CSIR-CDRI), Sitapur Road, Lucknow 226031, India
- Academy of Scientific and Innovative Research, Ghaziabad 201002, India
| | - Anees A Syed
- Pharmaceutics & Pharmacokinetics Division, CSIR-Central Drug Research Institute (CSIR-CDRI), Sitapur Road, Lucknow 226031, India
| | - Athar Husain
- Pharmaceutics & Pharmacokinetics Division, CSIR-Central Drug Research Institute (CSIR-CDRI), Sitapur Road, Lucknow 226031, India
| | - Guru R Valicherla
- Pharmaceutics & Pharmacokinetics Division, CSIR-Central Drug Research Institute (CSIR-CDRI), Sitapur Road, Lucknow 226031, India
| | - Jiaur R Gayen
- Pharmaceutics & Pharmacokinetics Division, CSIR-Central Drug Research Institute (CSIR-CDRI), Sitapur Road, Lucknow 226031, India
- Academy of Scientific and Innovative Research, Ghaziabad 201002, India
- Pharmacology Division, CSIR-Central Drug Research Institute (CSIR-CDRI), Lucknow 226031, India
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Ahmed OAA, El-Bassossy HM, El-Sayed HM, El-Hay SSA. Rp-HPLC Determination of Quercetin in a Novel D-α-Tocopherol Polyethylene Glycol 1000 Succinate Based SNEDDS Formulation: Pharmacokinetics in Rat Plasma. Molecules 2021; 26:molecules26051435. [PMID: 33800848 PMCID: PMC7961457 DOI: 10.3390/molecules26051435] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 02/23/2021] [Accepted: 03/02/2021] [Indexed: 12/23/2022] Open
Abstract
Despite its proven efficacy in diverse metabolic disorders, quercetin (QU) for clinical use is still limited because of its low bioavailability. D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS) is approved as a safe pharmaceutical adjuvant with marked antioxidant and anti-inflammatory activities. In the current study, several QU-loaded self-nanoemulsifying drug delivery systems (SNEDDS) were investigated to improve QU bioavailability. A reversed phase high performance liquid chromatography (RP-HPLC) method was developed, for the first time, as a simple and sensitive technique for pharmacokinetic studies of QU in the presence of TPGS SNEDDS formula in rat plasma. The analyses were performed on a Xterra C18 column (4.6 × 100 mm, 5 µm) and UV detection at 280 nm. The analytes were separated by a gradient system of methanol and phosphate buffer of pH 3. The developed RP-HPLC method showed low limit of detection (LODs) of 7.65 and 22.09 ng/mL and LOQs of 23.19 and 66.96 ng/mL for QU and TPGS, respectively, which allowed their determination in real rat plasma samples. The method was linear over a wide range, (30-10,000) and (100-10,000) ng/mL for QU and TPGS, respectively. The selected SNEDDS formula, containing 50% w/w TPGS, 30% polyethylene glycol 200 (PEG 200), and 20% w/w pumpkin seed oil (PSO), showed a globule size of 320 nm and -28.6 mV zeta potential. Results of the pharmacokinetic studies showed 149.8% improvement in bioavailability of QU in SNEDDS relative to its suspension. The developed HPLC method proved to be simple and sensitive for QU and TPGS simultaneous determination in rat plasma after oral administration of the new SNEDDS formula.
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Affiliation(s)
- Osama A. A. Ahmed
- Department of Pharmaceutics, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Center of Excellence for Drug Research and Pharmaceutical Industries, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Mohamed Saeed Tamer Chair for Pharmaceutical Industries, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Correspondence:
| | - Hany M. El-Bassossy
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt;
| | - Heba M. El-Sayed
- Department of Analytical Chemistry, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt; (H.M.E.-S.); (S.S.A.E.-H.)
| | - Soad S. Abd El-Hay
- Department of Analytical Chemistry, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt; (H.M.E.-S.); (S.S.A.E.-H.)
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Au-Co nanoparticles-embedded N-doped carbon nanotube hollow polyhedron modified electrode for electrochemical determination of quercetin. Mikrochim Acta 2020; 187:546. [PMID: 32886168 DOI: 10.1007/s00604-020-04531-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 08/22/2020] [Indexed: 10/23/2022]
Abstract
A core-shell ZIF-8@ZIF-67 was synthesized and pyrolyzed to get a Co nanoparticles-embedded N-doped carbon nanotube hollow polyhedron (Co@NCNHP). Then Au nanoparticles were formed on the surface and core of Co@NCNHP to obtain an Au-Co bimetal decorated NCNHP (Au-Co@NCNHP). The resultant nanocomposite was characterized by various methods including transmission electron microscopy, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The Au-Co@NCNHP-based electrochemical sensor displayed an obviously high electrocatalytic response to the oxidation of quercetin, which was attributed to the synergistic effects of Au-Co bimetal nanoparticles and N-doped carbon nanotube with hollow polyhedron. Under the optimal conditions, the oxidation peak currents exhibited a wide linear dynamic range for quercetin concentration from 0.050 to 35.00 μmol/L, and the detection limit was 0.023 ± 0.002 μmol/L (S/N = 3). The analytical applications of the proposed electrochemical sensor were checked by determining the content of quercetin in medical and onion samples with satisfactory results. Grapical abstract.
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Vinothkumar V, Sangili A, Chen SM, Veerakumar P, Lin KC. Sr-Doped NiO3 nanorods synthesized by a simple sonochemical method as excellent materials for voltammetric determination of quercetin. NEW J CHEM 2020. [DOI: 10.1039/c9nj05660b] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
A fabricated Sr-doped NiO3 nanorod-modified GCE was developed for electrochemical sensing of quercetin.
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Affiliation(s)
- Venkatachalam Vinothkumar
- Department of Chemical Engineering and Biotechnology
- National Taipei University of Technology
- Taipei 10608
- Republic of China
| | - Arumugam Sangili
- Department of Chemical Engineering and Biotechnology
- National Taipei University of Technology
- Taipei 10608
- Republic of China
| | - Shen-Ming Chen
- Department of Chemical Engineering and Biotechnology
- National Taipei University of Technology
- Taipei 10608
- Republic of China
| | - Pitchaimani Veerakumar
- Department of Chemistry
- National Taiwan University
- Taipei
- Republic of China
- Institute of Atomic and Molecular Sciences
| | - King-Chuen Lin
- Department of Chemistry
- National Taiwan University
- Taipei
- Republic of China
- Institute of Atomic and Molecular Sciences
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Gupta K, Sharma A, Gupta R, Dixit S, Singh SP, Das M, Dwivedi PD. Simple Extraction Cum RP-HPLC Method for Estimation of Nanotized Quercetin in Serum and Tissues of Mice. Pharm Chem J 2018. [DOI: 10.1007/s11094-018-1786-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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7
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Wu J, Xiao D, Zhao H, He H, Peng J, Wang C, Zhang C, He J. A nanocomposite consisting of graphene oxide and Fe3O4 magnetic nanoparticles for the extraction of flavonoids from tea, wine and urine samples. Mikrochim Acta 2015. [DOI: 10.1007/s00604-015-1575-8] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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8
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Ko KP. Isoflavones: chemistry, analysis, functions and effects on health and cancer. Asian Pac J Cancer Prev 2015; 15:7001-10. [PMID: 25227781 DOI: 10.7314/apjcp.2014.15.17.7001] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Isoflavones are phytoestrogens and natural plant compounds which are similar to 17-β-estradiol in chemical structure. It is known that they can act as estrogen agonists or antagonists, depending on endocrine estrogenic levels, but actions of isoflavones are rather complex due to large number of variables such as chemical structures and mechanisms. Some hypotheses on biological mechanisms have not satisfactorily been confirmed to date and human epidemiological and experimental studies have been relatively limited. Nevertheless, isoflavones and isoflavone rich foods have become a focus on interest due to positive health benefits on many diseases, especially prevention of hormone-related cancers, cardiovascular disease, osteoporosis, and adverse postmenopausal symptoms, and improvement of physiological condition such as maintaining cognitive function. This review provides an overview of chemistry, analytical techniques (focused on human biospecimens), functions including biological mechanisms, and effects of isoflavones, on the basis of the available meta-analysis and review articles and some original articles, on health and cancer.
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Affiliation(s)
- Kwang-Pil Ko
- Department of Preventive Medicine, Gachon University Graduate School of Medicine, Incheon, Korea E-mail :
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9
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V DK, Verma PRP, Singh SK, Viswanathan S. LC-ESI-MS/MS analysis of quercetin in rat plasma after oral administration of biodegradable nanoparticles. Biomed Chromatogr 2015; 29:1731-6. [PMID: 25973544 DOI: 10.1002/bmc.3486] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 03/20/2015] [Accepted: 03/31/2015] [Indexed: 12/28/2022]
Abstract
A simple, rapid and sensitive LC-MS/MS method was developed and validated for the determination of free quercetin in rat plasma, using fisetin as internal standard. The detection was performed by negative ion electrospray ionization under selected reaction monitoring. Chromatographic separation (isocratic elution) was carried out using acetonitrile-10 m m ammonium formate (80:20, v/v) with 0.1% v/v formic acid. The lower limit of quantification (4.928 ng/mL) provided high sensitivity for the detection of quercetin in rat plasma. The linearity range was from 5 to 2000 ng/mL. Intra- and inter-day variability (RSD) of quercetin extraction from rat plasma was <4.19 and 1.37% with accuracies of 98.77 and 99.67%. The method developed was successfully applied for estimating free quercetin in rat plasma, after oral administration of quercetin-loaded biodegradable nanoparticles (QLN) and quercetin suspension. QLN (C(max), 1277.34 ± 216.67 ng/mL; AUC, 17,458.25 ± 3152.95 ng hr/mL) showed a 5.38-fold increase in relative bioavailability as compared with quercetin suspension (C(max), 369.2 ± 108.07 ng/mL; AUC, 3276.92 ± 396.67 ng hr/mL).
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Affiliation(s)
- Dinesh Kumar V
- Department of Pharmaceutical Sciences and Technology, Birla Institute of Technology, Mesra, Ranchi, Jharkhand, India
| | - Priya Ranjan Prasad Verma
- Department of Pharmaceutical Sciences and Technology, Birla Institute of Technology, Mesra, Ranchi, Jharkhand, India
| | - Sandeep Kumar Singh
- Department of Pharmaceutical Sciences and Technology, Birla Institute of Technology, Mesra, Ranchi, Jharkhand, India
| | - S Viswanathan
- Micro-Therapeutic Research Labs Private Limited, Chennai, 600097, India
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10
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Hashimoto T, Ueda Y, Oi N, Sakakibara H, Piao C, Ashida H, Goto M, Kanazawa K. Effects of Combined Administration of Quercetin, Rutin, and Extract of White Radish Sprout Rich in Kaempferol Glycosides on the Metabolism in Rats. Biosci Biotechnol Biochem 2014; 70:279-81. [PMID: 16428850 DOI: 10.1271/bbb.70.279] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Quercetin, rutin, the extract of white radish sprout rich in kaempferol glycosides, and their combination were intragastrically administered to Wistar rats to investigate the interactive metabolism of these flavonoids. The combined administration of these flavonoids changed the concentrations of the metabolites in plasma as compared with the concentrations after the administration of a single compound.
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Affiliation(s)
- Takashi Hashimoto
- Department of Biofunctional Chemistry, Faculty of Agriculture, Kobe University, Japan.
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Possible Evidence of Contamination by Catechins in Deconjugation Enzymes fromHelix pomatiaandAbalone entrails. Biosci Biotechnol Biochem 2014; 75:1506-10. [DOI: 10.1271/bbb.110210] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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12
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He H, Yuan D, Gao Z, Xiao D, He H, Dai H, Peng J, Li N. Mixed hemimicelles solid-phase extraction based on ionic liquid-coated Fe3O4/SiO2 nanoparticles for the determination of flavonoids in bio-matrix samples coupled with high performance liquid chromatography. J Chromatogr A 2014; 1324:78-85. [DOI: 10.1016/j.chroma.2013.11.021] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 11/06/2013] [Accepted: 11/09/2013] [Indexed: 11/28/2022]
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13
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Liu L, Chen Z. Analysis of four alkaloids of Coptis chinensis in rat plasma by high performance liquid chromatography with electrochemical detection. Anal Chim Acta 2012; 737:99-104. [PMID: 22769040 DOI: 10.1016/j.aca.2012.05.054] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 05/18/2012] [Accepted: 05/22/2012] [Indexed: 02/08/2023]
Abstract
A sensitive and precise high performance liquid chromatography (HPLC)-electrochemical detection (ECD) method has been developed for the simultaneous determination of four isoquinoline alkaloids including berberine, jatrorrhizine, coptisine and palmatine in Chinese medicine Coptis chinensis. The typical HPLC analysis was performed on WondaSil(®) C18-WR column (250×4.6 mm, 5 μm) with the mobile phase comprising 40 mM phosphate buffer (pH 7.0)-acetonitrile (40:60, v/v) at the flow rate of 0.8 mL min(-1). The electrochemical detection employed a three electrode system with a bare glassy carbon electrode at +1.3 V versus the Ag/AgCl reference electrode. The limits of detection (LODs) of four alkaloids ranged from 0.01 to 0.03 μmol L(-1) and the LOD of berberine was 80 times lower than LOD obtained by UV detection. The rat plasma samples were assayed after oral administration of the traditional Chinese medicine Coptis chinensis by the proposed HPLC-ECD method. The recoveries of this method were ranging from 88.0 to 116%, with the relative standard deviation lower than 3.1% for intra-day precision and 5.7% for inter-day precision. These results show that HPLC-ECD is a useful tool for the quality control of herbal medicine Coptis chinensis and also for pharmacokinetic studies.
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Affiliation(s)
- Lihong Liu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Wuhan University, Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan, China
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Liu L, Li S, Chen Z. Simultaneous determination of tetrandrine and fangchinoline in herbal medicine Stephania tetrandra S. Moore by liquid chromatography with electrochemical detection. J Pharm Biomed Anal 2012; 61:252-5. [DOI: 10.1016/j.jpba.2011.11.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Revised: 11/25/2011] [Accepted: 11/25/2011] [Indexed: 10/14/2022]
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15
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Genotoxicity and apoptosis in Drosophila melanogaster exposed to benzene, toluene and xylene: Attenuation by quercetin and curcumin. Toxicol Appl Pharmacol 2011; 253:14-30. [DOI: 10.1016/j.taap.2011.03.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Revised: 02/11/2011] [Accepted: 03/07/2011] [Indexed: 12/18/2022]
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Determination of quercetin and resveratrol in whole blood--implications for bioavailability studies. Molecules 2010; 15:6570-9. [PMID: 20877244 PMCID: PMC6257724 DOI: 10.3390/molecules15096570] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Revised: 08/27/2010] [Accepted: 09/14/2010] [Indexed: 11/26/2022] Open
Abstract
Resveratrol (trans-3,4',5-trihydroxystilbene) and quercetin (3,3’,4’,5,7-pentahydroxyflavone) are two naturally occurring polyphenols with the potential to exert beneficial health effects. Since their low bioavailability is a major obstacle to biomedical applications, efforts are being made to improve their absorption and slow down phase II metabolism. An accurate evaluation of the corresponding levels in the bloodstream is important to assess delivery strategies, as well as to verify claims of efficacy based on in vitro results. In the present work we have optimized a simple method ensuring complete stabilization and extraction of resveratrol and quercetin from whole blood. The suitability of different protocols was evaluated by measuring the recovery of polyphenol and internal standard from spiked blood samples via HPLC/UV analysis. The optimized procedure ensured a satisfactory recovery of both internal standards and compounds. Comparing plasma and whole blood, up to 76% of the analyte, being associated with the cellular fraction, was unaccounted for when examining only plasma. This indicates the importance of analysing whole blood rather than plasma to avoid underestimating polyphenol absorption in bioavailability studies.
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Simultaneous determination of four 5-hydroxy polymethoxyflavones by reversed-phase high performance liquid chromatography with electrochemical detection. J Chromatogr A 2009; 1217:642-7. [PMID: 20022018 DOI: 10.1016/j.chroma.2009.11.097] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Revised: 11/25/2009] [Accepted: 11/30/2009] [Indexed: 11/23/2022]
Abstract
Accumulating evidence has suggested the potential health-promoting effects of 5-hydroxy polymethoxyflavones (5-OH-PMFs) naturally existing in citrus genus. However, research efforts are hampered by the lack of reliable and sensitive methods for their determination in plant materials and biological samples. Using reversed-phase high performance liquid chromatography (HPLC) equipped with electrochemical (EC) detection, we have developed a fast and highly sensitive method for quantification of four 5-OH-PMFs, namely 5-hydroxy-6,7,8,3',4'-pentamethoxyflavone, 5-hydroxy-3,6,7,8,3',4'-hexamethoxyflavone, 5-hydroxy-6,7,4'-trimethoxyflavone, and 5-hydroxy-6,7,8,4'-tetramethoxyflavone. The method was fully validated in terms of linearity, accuracy and precision. The limit of detection (LOD) was determined as being between 0.65 and 1.8ng/mL (ppb), demonstrating an over 160 times higher sensitivity in comparison with the previously reported method using UV detection. The recovery rate of the method was between 96.17% and 110.82%, and the precision for the retention times and peak areas was all below 13%. The method was successfully used to quantify 5-OH-PMFs with a wide range of abundance in the citrus products and preparations, such as orange juice, citrus peel, and dried tangerine peel. The quantification method for 5-OH-PMFs developed herein could be useful for the nutritional and pharmacological studies of these compounds in future.
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Marsden DA, Jones DJL, Britton RG, Ognibene T, Ubick E, Johnson GE, Farmer PB, Brown K. Dose-response relationships for N7-(2-hydroxyethyl)guanine induced by low-dose [14C]ethylene oxide: evidence for a novel mechanism of endogenous adduct formation. Cancer Res 2009; 69:3052-9. [PMID: 19276345 DOI: 10.1158/0008-5472.can-08-4233] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Ethylene oxide (EO) is widely used in the chemical industry and is also formed in humans through the metabolic oxidation of ethylene, generated during physiologic processes. EO is classified as a human carcinogen and is a direct acting alkylating agent, primarily forming N7-(2-hydroxyethyl)guanine (N7-HEG). To conduct accurate human risk assessments, it is vital to ascertain the relative contribution of endogenously versus exogenously derived DNA damage and identify the sources of background lesions. We have therefore defined in vivo dose-response relationships over a concentration range relevant to human EO exposures using a dual-isotope approach. By combining liquid chromatography-tandem mass spectrometry and high-performance liquid chromatography-accelerator mass spectrometry analysis, both the endogenous and exogenous N7-HEG adducts were quantified in tissues of [(14)C]EO-treated rats. Levels of [(14)C]N7-HEG induced in spleen, liver, and stomach DNA increased in a linear manner from 0.002 to 4 adducts/10(8) nucleotides. More importantly, the extent of damage arising through this route was insignificant compared with the background abundance of N7-HEG naturally present. However, at the two highest doses, [(14)C]EO exposure caused a significant increase in endogenous N7-HEG formation in liver and spleen, suggesting that EO can induce physiologic pathways responsible for ethylene generation in vivo and thereby indirectly promote N7-HEG production. We present evidence for a novel mechanism of adduct formation to explain this phenomenon, involving oxidative stress and 1-aminocyclopropane-1-carboxylic acid as a potential biosynthetic precursor to ethylene in mammalian cells. Based on the proposed pathway, N7-HEG may have potential as a biomarker of cellular oxidative stress.
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Affiliation(s)
- Debbie A Marsden
- Department of Cancer Studies and Molecular Medicine, University of Leicester, Leicester, United Kingdom
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19
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Determination of quercetin and its glucosides in onion by electrochemical methods. Anal Chim Acta 2008; 617:22-31. [DOI: 10.1016/j.aca.2008.01.037] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2007] [Revised: 01/13/2008] [Accepted: 01/15/2008] [Indexed: 11/18/2022]
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20
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Özkan SA. LC with Electrochemical Detection. Recent Application to Pharmaceuticals and Biological Fluids. Chromatographia 2007. [DOI: 10.1365/s10337-007-0223-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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21
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General method for determining flavonoids in medicinal plants and raw cosmetics using HPLC with a photodiode array detector. Pharm Chem J 2007. [DOI: 10.1007/s11094-007-0051-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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22
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Bolarinwa A, Linseisen J. Validated application of a new high-performance liquid chromatographic method for the determination of selected flavonoids and phenolic acids in human plasma using electrochemical detection. J Chromatogr B Analyt Technol Biomed Life Sci 2005; 823:143-51. [PMID: 16019270 DOI: 10.1016/j.jchromb.2005.06.024] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2004] [Revised: 06/08/2005] [Accepted: 06/10/2005] [Indexed: 11/29/2022]
Abstract
We developed a sensitive method for determination of 23 flavonoids and phenolic acids, which represent phenolic acids and five subclasses of flavonoids. Plasma samples were extracted with selective solid-phase-extraction columns and separated by RP-high-performance liquid chromatography (HPLC). For detection an electrochemical detector was used. Identification and test of purity were carried out via retention times and spectra analyses. Limits of detection varied from 1.45 to 22.27 nmol/l. Recovery varied from 81% to 106%. Reproducibility for all analytes was below 10% (coefficient of variation, CV (%)) and ranged between 3.1% and 9.8%. This method can be applied to samples from interventional studies as well as observational studies.
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Affiliation(s)
- Adrian Bolarinwa
- Unit of Human Nutrition and Cancer Prevention, Centre of Life Science, Technical University Munich, Alte Akademie 16, 85350 Freising-Weihenstephan, Germany
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24
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Aguilar-Sánchez R, Ahuatl-García F, Dávila-Jiménez MM, Elizalde-González MP, Guevara-Villa MRG. Chromatographic and electrochemical determination of quercetin and kaempferol in phytopharmaceuticals. J Pharm Biomed Anal 2005; 38:239-49. [PMID: 15925214 DOI: 10.1016/j.jpba.2004.12.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2004] [Revised: 12/22/2004] [Accepted: 12/30/2004] [Indexed: 10/25/2022]
Abstract
An NP-HPLC method both with diode-array (DAD) and electrochemical detection (ED) was developed and validated for the determination of quercetin and kaempferol, the principal active constituents in phytopharmaceuticals of Ginkgo Biloba. Calculated retention of the two flavonoids was contrasted with experimental values in five different reversed phase columns for methanol-water, acetonitrile-water, THF-water and dioxane-hexane binary mixtures as mobile phases. The capacity factor k, selectivity alpha and asymmetry factor F were evaluated and compared in DAD-RP-HPLC, DAD-NP-HPLC, ED-RP-HPLC and ED-NP-HPLC. The methods were used for the quantitative analysis of acid hydrolyzed extracts of tablet phytopharmaceuticals. Calibration curves were linear within the range 10 and 40 microg ml(-1) for the DAD and 10-270 microg ml(-1) for the ED, whereby limits of detection ranged from 0.5 microg ml(-1) (quercetin) to 0.1 microg ml(-1) (kaempferol). The electrochemical method based on differential pulse voltammetry (DPV) with a C-PVC electrode resolved the quercetin and kaempferol peaks and exhibited a two orders higher sensitivity in comparison with a carbon fiber electrode. DPV calibration curves were linear within the range 96-300 microg ml(-1) for quercetin and 68-960 microg ml(-1) for kaempferol. The respective oxidation peaks appeared at 462 and 518+/-2 mV and were used in the direct determination of quercetin in extracts of commercial phytopharmaceuticals.
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Affiliation(s)
- R Aguilar-Sánchez
- Facultad de Ciencias Químicas, Universidad Autónoma de Puebla, Apartado Postal J-55, Puebla, Pue. 72571, Mexico
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25
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Jin D, Hakamata H, Takahashi K, Kotani A, Kusu F. Determination of quercetin in human plasma after ingestion of commercial canned green tea by semi-micro HPLC with electrochemical detection. Biomed Chromatogr 2005; 18:662-6. [PMID: 15386501 DOI: 10.1002/bmc.370] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Determination of quercetin in human plasma was carried out by semi-micro high-performance liquid chromatography with electrochemical detection. Peak heights for quercetin were found to be linearly related to the amount of each quercetin injected from 1.5 to 750 pg. The detection limit (signal-noise ratio, S/N = 3) of the present method for quercetin was 0.3 pg. Glucuronic and sulfate forms of quercetin in plasma were hydrolyzed enzymatically using beta-glucuronidase and sulfatase, respectively. Quercetin in plasma and the hydrolyzed solution were extracted with ethyl acetate and determined by the present method. The time courses of concentrations of quercetin in human plasma showed maxima at 1-1.5 h after ingestion of 340 mL of commercial canned green tea.
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Affiliation(s)
- Dongri Jin
- Chemistry Department of Science and Engineering College, Yanbian University, 105 Gongyuan Rd, Yanji 133002, People's Republic of China
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26
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Jones DJL, Lamb JH, Verschoyle RD, Howells LM, Butterworth M, Lim CK, Ferry D, Farmer PB, Gescher AJ. Characterisation of metabolites of the putative cancer chemopreventive agent quercetin and their effect on cyclo-oxygenase activity. Br J Cancer 2004; 91:1213-9. [PMID: 15292928 PMCID: PMC2747694 DOI: 10.1038/sj.bjc.6602091] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Quercetin (3,5,7,3′,4′-pentahydroxyflavone) is a flavone with putative ability to prevent cancer and cardiovascular diseases. Its metabolism was evaluated in rats and human. Rats received quercetin via the intravenous (i.v.) route and metabolites were isolated from the plasma, urine and bile. Analysis was by high-performance liquid chromatography and confirmation of species identity was achieved by mass spectrometry. Quercetin and isorhamnetin, the 3′-O-methyl analogue, were found in both the plasma and urine. In addition, several polar peaks were characterised as sulphated and glucuronidated conjugates of quercetin and isorhamnetin. Extension of the metabolism studies to a cancer patient who had received quercetin as an i.v. bolus showed that (Quercetin removed) isorhamnetin and quercetin 3′-O-sulphate were major plasma metabolites. As a catechol, quercetin can potentially be converted to a quinone and subsequently conjugated with glutathione (GSH). Oxidation of quercetin with mushroom tyrosinase in the presence of GSH furnished GSH conjugates of quercetin, two mono- and one bis-substituted conjugates. However, these species were not found in biomatrices in rats treated with quercetin. As cyclo-oxygenase-2 (COX-2) expression is mechanistically linked to carcinogenesis, we examined whether quercetin and its metabolites can inhibit COX-2 in a human colorectal cancer cell line (HCA-7). Isorhamnetin and its 4′-isomer tamarixetin were potent inhibitors, reflected in a 90% decrease in prostaglandin E-2 (PGE-2) levels, a marker of COX-2 activity. Quercetin was less effective, with a 50% decline. Quercetin 3- and 7-O-sulphate had no effect on PGE-2. The results indicate that quercetin may exert its pharmacological effects, at least in part, via its metabolites.
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Affiliation(s)
- D J L Jones
- Cancer Biomarkers and Prevention Group, Department of Biochemistry, Biocentre, University of Leicester, Leicester LE1 7RH, UK.
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27
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Lian H, Kang Y, Bi S, Arkin Y, Shao D, Li D, Chen Y, Dai L, Gan N, Tian L. Direct determination of trace aluminum with quercetin by reversed-phase high performance liquid chromatography. Talanta 2004; 62:43-50. [DOI: 10.1016/s0039-9140(03)00405-3] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2003] [Revised: 06/08/2003] [Accepted: 06/09/2003] [Indexed: 10/27/2022]
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28
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Wang FM, Yao TW, Zeng S. Determination of quercetin and kaempferol in human urine after orally administrated tablet of ginkgo biloba extract by HPLC. J Pharm Biomed Anal 2003; 33:317-21. [PMID: 12972097 DOI: 10.1016/s0731-7085(03)00255-3] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A sensitive, simple and accurate method was developed for determination of quercetin and kaempferol in human urine by reversed phase high performance liquid chromatography. The urine samples were analyzed on C18 column. Quercetin and kaempferol were analyzed simultaneously with good separation. UV detector was set at 380 nm. There was a linear relationship between chromatographic area of analytes and concentration of analytes over the concentration range 1.638-81.90 and 1.872-93.60 ng/ml for quercetin and kaempferol, respectively. The recovery of the assay was 99.7+/-6.2 and 97.4+/-7.2% for quercetin and kaempferol, respectively. The within-day and between-day coefficients of variation were less than 9.7 and 16.5% (RSD), respectively. The limit of detection was 1.0 ng/ml for quercetin and 1.1 ng/ml for kaempferol. The limit of quantitation was 1.61+/-0.11 ng/ml (n=5) for quercetin and 1.85+/-0.11 ng/ml (n=5) for kaempferol. The method developed has been applied to determine quercetin and kaempferol after orally administrated tablet of Ginkgo biloba extract in human urine.
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Affiliation(s)
- F M Wang
- Department of Pharmaceutical Analysis and Drug Metabolism, College of Pharmaceutical Sciences, 353 Yan An Road, Zhejiang University, 310031 Hangzhou, Zhejiang, PR China
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29
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Ishii K, Furuta T, Kasuya Y. High-performance liquid chromatographic determination of quercetin in human plasma and urine utilizing solid-phase extraction and ultraviolet detection. J Chromatogr B Analyt Technol Biomed Life Sci 2003; 794:49-56. [PMID: 12888197 DOI: 10.1016/s1570-0232(03)00398-2] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
An HPLC method for determining quercetin in human plasma and urine is presented for application to the pharmacokinetic study of rutin. Isocratic reversed-phase HPLC was employed for the quantitative analysis by using kaempferol as an internal standard. Solid-phase extraction was performed on an Oasis HLB cartridge (>95% recovery). The HPLC assay was carried out using a Luna ODS-2 column (150 x 2.1 mm I.D., 5 microm particle size). The mobile phase was acetonitrile-10 mM ammonium acetate solution containing 0.3 mM EDTA-glacial acetic acid, 29:70:1 (v/v, pH 3.9) and 26:73:1 (v/v, pH 3.9) for the determination of plasma and urinary quercetin, respectively. The flow-rate was 0.3 ml/min and the detection wavelength was set at 370 nm. Calibration of the overall analytical procedure gave a linear signal (r>0.999) over a concentration range of 4-700 ng/ml of quercetin in plasma and 20-1000 ng/ml of quercetin in urine. The lower limit of quantification was approximately 7 ng/ml of quercetin in plasma and approximately 35 ng/ml in urine. The detection limit (defined at a signal-to-noise ratio of about 3) was approximately 0.35 ng/ml in plasma and urine. A preliminary experiment to investigate the plasma concentration and urinary excretion of quercetin after oral administration of 200 mg of rutin to a healthy volunteer demonstrated that the present method was suitable for determining quercetin in human plasma and urine.
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Affiliation(s)
- Kazuo Ishii
- Kyorin University, School of Health Sciences, 476 Miyasita, Hachioji, 19486 Tokyo 19486, Japan.
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30
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Cai H, Verschoyle RD, Steward WP, Gescher AJ. Determination of the ?avone tricin in human plasma by high-performance liquid chromatography. Biomed Chromatogr 2003; 17:435-9. [PMID: 14598326 DOI: 10.1002/bmc.260] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Tricin is a flavone constituent of brown rice and rice bran, which interferes potently with the survival of human-derived breast and colon cancer cells in vitro. A specific and simple high-performance liquid chromatographic (HPLC) method was developed for the determination of tricin in human plasma with UV-visible detection. HPLC separation on Hypersil-BDS C(18) (4.6 x 250 mm) was carried out with an isocratic mobile phase of 52% methanol in 0.1 m ammonium acetate, pH 5.10, containing 0.27 mm disodium ethylenediamine tetraacetic acid and detection at 355 nm. The retention times of tricin and quercetin (internal standard) were 14.2 and 7.8 min, respectively. The assay was linear in the range 1-100 microg/mL (r(2 ) > or = 0.995). Tricin in plasma was efficiently extracted with 0.1 m acetic acid in acetone, and the recoveries were in the range 92.6-102.8% (n = 6) with relative standard deviation below 10% for three concentrations of tricin, 5, 10 and 100 microg/mL. The lower limit of quantitation (relative standard deviation <20%) was 1 microg/mL.
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Affiliation(s)
- Hong Cai
- Cancer Biomarkers and Prevention Research Group, Department of Oncology, University of Leicester, Leicester LE2 7LX, UK.
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31
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Wang CC, Prasain JK, Barnes S. Review of the methods used in the determination of phytoestrogens. J Chromatogr B Analyt Technol Biomed Life Sci 2002; 777:3-28. [PMID: 12270197 DOI: 10.1016/s1570-0232(02)00341-0] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Interest in analytical methods for plant estrogens (phytoestrogens) has risen sharply in the past 10 years. In this review, we examine the existing analytical methods based on separations by gas-liquid chromatography, high-performance liquid chromatography and capillary electrophoresis in addition to methods of detection by ultraviolet absorption, fluorescence, electrochemical oxidation/reduction and mass spectrometry. These methods are compared with other methods of phytoestrogen analysis utilizing immunoassay approaches. The advantages and disadvantages of each of these methods are highlighted and potential areas for further development identified.
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Affiliation(s)
- Chao-Cheng Wang
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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32
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Wittig J, Wittemer S, Veit M. Validated method for the determination of hydroquinone in human urine by high-performance liquid chromatography-coulometric-array detection. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 2001; 761:125-32. [PMID: 11585126 DOI: 10.1016/s0378-4347(01)00321-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The paper describes the computer aided method development and validation for the determination of hydroquinone in human urine from a clinical study on renal excretion of hydroquinone metabolites and the release of free hydroquinone in the urinary tract in order to evaluate the proposed urine disinfecting concept. The presented method uses high-performance liquid chromatography on reversed-phase material with a polar endcapping (Aqua-C18, 250x4.6 mm). Selective and sensitive determination (LOQ= 12.5 ng on-column) of the target compound was achieved by electrochemical array detection (CoulArray). Gradient and parameter optimization were supported by DryLab software in order to minimize efforts of the expensive and time-consuming method development. Specificity and selectivity were carried out by separation experiments involving the prodrug arbutin and the metabolites hydroquinone, hydroquinone glucuronide, and hydroquinone sulfate, respectively. Hydroquinone glucuronide reference standard was obtained from in vitro glucuronidation in a rat liver microsomes assay. The method was validated according to the criteria for validation of pharmaceutical bioanalytical methods as drafted by the US Department of Health and Human Services, 1998.
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Affiliation(s)
- J Wittig
- Zentralinstitut Arzneimettelforschung GmbH, Sinzig, Germany.
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33
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Ishii K, Furuta T, Kasuya Y. Determination of rutin in human plasma by high-performance liquid chromatography utilizing solid-phase extraction and ultraviolet detection. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 2001; 759:161-8. [PMID: 11499620 DOI: 10.1016/s0378-4347(01)00224-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
An HPLC method for determining a flavonol glycoside, rutin, in human plasma is presented for application to the pharmacokinetic study. Isocratic reversed-phase HPLC was employed for the quantitative analysis by using kaempferol-3-rutinoside as an internal standard. Solid-phase extraction was performed on an Oasis MAX cartridge possessing reversed-phase and anion-exchange functions (recovery, approximately 80%). The HPLC assay was carried out using a Luna ODS-2 column (150 x 2.1 mm I.D., 5 microm particle size). The mobile phase was acetonitrile-10 mM ammonium acetate solution containing 0.3 mM EDTA-glacial acetic acid (16.5:82.5:1, v/v, pH 3.8). The flow-rate was 0.3 ml/min. The detection wavelength was set at 370 nm. Calibration of the overall analytical procedure gave a linear signal (r>0.9999) over a concentration range of 3-1,000 ng/ml of rutin in plasma. The lower limit of quantification was ca. 5 ng/ml of rutin in plasma. The detection limit (defined as signal-to-noise ratio of about 3) was approximately 0.75 ng/ml. A preliminary experiment to investigate the plasma concentration of rutin after oral administration of 500 mg of rutin to a healthy volunteer demonstrated that the present method was suitable for determining rutin in human plasma.
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Affiliation(s)
- K Ishii
- Kyorin University, School of Health Sciences, Hachioji, Tokyo, Japan.
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34
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Erlund I, Alfthan G, Siren H, Ariniemi K, Aro A. Validated method for the quantitation of quercetin from human plasma using high-performance liquid chromatography with electrochemical detection. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 1999; 727:179-89. [PMID: 10360437 DOI: 10.1016/s0378-4347(99)00049-3] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A validated method for the quantitation of trace levels of quercetin from human plasma to be used in pharmacokinetic and biomarker studies is presented. Quercetin conjugates were hydrolysed enzymatically, plasma proteins were removed using a Bond Elut C18 extraction column and additional interferences were removed by extracting them into a toluene-dichloromethane mixture. The HPLC system consisted of an Inertsil ODS-3 column (250 x 4.0 mm) and a mobile phase with 59% methanol in phosphate buffer (pH 2.4). High selectivity and a low quantitation limit (0.63 microg/l) were achieved by using electrochemical detection at a low potential. The method has excellent reproducibility: R.S.D. values of peak-heights were 2% and 7.9%, respectively, for within-day and between-day precision. The method was applied to a small scale study of quercetin pharmacokinetics and quercetin was shown to be absorbed from a 20 mg dose. No free quercetin was detected in plasma and no evidence of significant amounts of quercetin glycosides in plasma was found.
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Affiliation(s)
- I Erlund
- Department of Nutrition, National Public Health Institute, Helsinki, Finland.
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