Quercetin In Plasma Research Articles

Magnetic molecularly imprinted polymer combined with high performance liquid chromatography for selective extraction and determination of the metabolic content of quercetin in rat plasma

In this study, a novel magnetic solid phase extraction adsorbent was prepared, namely Fe3O4@SiO2 as the carrier, quercetin as the template molecule, acrylamide (AM) as the functional monomer, ethylene glycol dimethacrylamide (EGDMA) as the crosslinker, 2,2′-azobisisobutyronitrile (AIBN) as the initiator to prepare magnetic molecularly imprinted polymer (MMIPs) with specific adsorption of quercetin by surface molecular imprinting technique. MMIPs were characterized by Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD) and transmission electron microscope (TEM). The binding properties of MMIPs were evaluated by isothermal adsorption, kinetic adsorption and selective adsorption experiments. The results showed that the saturated adsorption capacity and adsorption time were 17.9 μmol/g and 20 min, respectively, and showed high selectivity for quercetin. Under optimized conditions, the limit of detection (LOD) and limit of quantitation (LOQ) were 55.327 ng/mL and 184.413 ng/mL, respectively. The recovery and RSD were 85.34–95.67% and 3.36–6.59, respectively. We successfully combined magnetic solid phase extraction with high performance liquid chromatography (MSPE-HPLC-UV) for the enrichment, separation and detection of quercetin in rat plasma. The results showed that the peak and half-life of quercetin in plasma were 1.5 h (32.310 μg/mL) and 3 h, respectively. The method was simple, rapid and efficient, and could be applied to the separation and detection of quercetin in complex matrices, and also provides a basis for the separation and identification of other natural chemical components.

Pharmacokinetics and Novel Metabolite Identification of Tartary Buckwheat Extracts in Beagle Dogs Following Co-Administration with Ethanol.

Alcoholic liver disease (ALD) has become a critical global public health issue worldwide. Tartary buckwheat extracts exhibit potential therapeutic effects against ALD due to its antioxidant and anti-inflammatory activities. However, in vivo pharmacokinetics and metabolite identification of tartary buckwheat extracts have not been clearly elucidated. Accordingly, the current manuscript aimed to investigate pharmacokinetics and to identify novel metabolites in beagle dogs following oral co-administration of tartary buckwheat extracts and ethanol. To support pharmacokinetic study, a simple LC-MS/MS method was developed and validated for simultaneous determination of quercetin and kaempferol in beagle dog plasma. The conjugated forms of both analytes were hydrolyzed by β-glucuronidase and sulfatase followed by liquid-liquid extraction using methyl tert-butyl ether. In addition, another effective approach was established using advanced ultrafast liquid chromatography coupled with a Q-Exactive hybrid quadrupole orbitrap high resolution mass spectrometer to identify the metabolites in beagle dog biological samples including urine, feces, and plasma. The pharmacokinetic study demonstrated that the absolute oral bioavailability for quercetin and kaempferol was determined to be 4.6% and 1.6%, respectively. Oral bioavailability of quercetin and kaempferol was limited in dogs probably due to poor absorption, significant first pass effect, and biliary elimination, etc. Using high resolution mass spectrometric analysis, a total of nine novel metabolites were identified for the first time and metabolic pathways included methylation, glucuronidation, and sulfation. In vivo pharmacokinetics and metabolite identification results provided preclinical support of co-administration of tartary buckwheat extracts and ethanol in humans.

Simultaneous determination of four flavonoids in rat plasma after oral administration of Malus hupehensis (Pamp.) Rehd. extracts by UPLC‐MS/MS and its application to a pharmacokinetics study

A rapid, sensitive, selective, and accurate UPLC–MS/MS method was developed and fully validated for the simultaneous determination of quercitrin, phloridzin, quercetin, and phloretin in rat plasma after oral administration of Malus hupehensis (Pamp.) Rehd extracts. The pharmacokinetic parameters of oral phloridzin monomer and phloridzin in the extract were also compared. Plasma samples were processed with a simple protein precipitation technique using methanol, followed by chromatographic separation using a Sun Fire ™C18 column. Bergenin was used an internal standard (IS). A 15.0 min linear gradient elution was used at a flow rate of 0.8 mL/min with a mobile phase of 0.1% formic acid in water and acetonitrile. The analytes and IS were detected using negative ion electrospray ionization in multiple reaction monitoring mode. The developed method exhibited good linearity (r ≥ 0.9911), and the lower limits of quantification ranged from 0.2 to 0.8 ng/mL for the four analytes. Intra-day and inter-day precision were both less than 8.5% and were within the acceptable limits. Matrix effect and recovery efficiency of all analytes were found to be >76.2% and >71.4%, respectively. Stability results showed that the analytes were stable at all conditions. Additionally, the carry-over effect and dilution effect were within the acceptance range. The developed method was successfully applied to a pharmacokinetic study of four analytes in rats after oral administration of Malus hupehensis (Pamp.) Rehd. extracts.

Simultaneous UPLC\u2013TQ-MS/MS determination of six active components in rat plasma: application in the pharmacokinetic study of Cyclocarya paliurus leaves

BackgroundCyclocarya paliurus (Batal.) Ijinskaja (CP) is a monotypic genus plant, also called sweet tea tree that belongs to the Juglandaceae family, which is mainly distributed in the subtropical highlands in China. Our previous work has verified that CP leaves exhibit a potent hyperglycemic effect by inhibiting pancreatic β cell apoptosis through the regulation of MPAK and Akt signaling pathways. However, the components that contribute to this potential health benefit remain undiscovered.MethodA sensitive, reliable, and validated ultra-performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (UPLC–TQ-MS/MS) method was developed to simultaneously determine the presence of six active components (neochlorogenic acid, chlorogenic acid, quercetin-3-O-glucuronide, kaempferol-3-O-rhamnoside, quercetin, and kaempferol) in rat plasma after a single oral administration (in a dosage of 10.5 g/kg) of an extract of CP leaves to rats. The separation was performed on a Waters ACQUITY BEH C18 column (50 mm × 2.1 mm, 1.7 μm). The detection was conducted by multiple reaction monitoring (MRM) in negative ionization mode. The two highest abundant MRM transitions without interference were optimized for each analyte. Acetonitrile and formic acid aqueous solution (0.1%) was used as the mobile phase at a flow rate of 0.3 ml/min.ResultThe precision, accuracy, and recovery all satisfied the criteria of international guidance (Bioanalytical Method Validation Guidance for Industry, Food and Drug Administration), and the analytes were stable in plasma for all tested conditions. The main pharmacokinetic parameters were calculated by plasma concentration versus time profiles using the pharmacokinetics program.ConclusionThe pharmacokinetic parameters of each compound can facilitate future clinical studies.

UPLC-MS/MS quantification of quercetin in plasma and urine following parenteral administration

BackgroundStudy of pharmacokinetics of quercetin (Qu) and its derivatives after infusion is required in order to better understand mechanisms of therapeutic action of the formulation and development the strategic approaches to treat the underlying disease and pathologically similar syndromes. A pharmacokinetic study of Qu products is a complex analytical problem.ResultsWe developed and validated a new method for quantification of Qu and its metabolites in human plasma and urine following intravenous administration of Qu formulation. The method is based on the solid-phase extraction with the help of Oasis® HLB cartridges and ultra-performance liquid chromatography - tandem mass spectrometry (UPLC-MS/MS) quantification. The calibration curves plotted for concentration range of 25–3000 ng/ml for Qu and isorhamnetin in blood plasma and of 100–8000 ng/ml for the same substances in urine were best described by a quadratic function. Qu conjugates underwent preliminary hydrolysis by the mixture of enzymes of sulphatase and β-glucuronidase. The antioxidant L-cysteine mixed with ascorbic acid was used for stabilization of Qu and its metabolites during handling of samples and chromatographic runs with mass detection. The method validation as well as the stability study results confirmed that the developed method meets the established requirements (selectivity, lower limit of quantification, accuracy, precision, recovery).The main pharmacokinetic parameters of Qu and its metabolites were determined in blood plasma and urine after intravenous administration of Corvitin® (parenteral formulation combining Qu and polyvinylpyrrolidone at a ratio of 1:9) in 12 healthy volunteers.ConclusionsWe showed that the method development for Qu quantification in biological matrixes is valuable and reliable.

A simple sensitive UFLC-MS/MS method for the simultaneous quantification of artesunate, dihydroartemisinin and quercetin in rat plasma and its application to pharmacokinetic studies.

An ultrafast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method was developed for the simultaneous estimation of artesunate (ART), dihydroartemisinin (DHA, an active metabolite of ART) and quercetin (QRT) in rat plasma. The separation was achieved using a Zorbax C18 column (3 μm, 50 mm × 4.6 mm) as a stationary phase with a mobile phase of 0.1% formic acid (10% by volume) and methanol (90% by volume) at a flow rate of 0.4 mL min−1 and an injection volume of 10 μL. Artemisinin (ATM) was used as the internal standard (IS). Mass detection was performed by electrospray ionization (ESI)-tandem mass spectrometry via multiple reaction monitoring (MRM) in positive mode except for QRT, where negative ionization was used. The extraction recoveries of ART, DHA, and QRT from plasma were found to be 91.05–99.62%, 95.12–98.56% and 89.35–98.90%, respectively. The developed method was validated and successfully applied to the quantitative analysis of ART, DHA and QRT in plasma samples after the oral administration of ART and ART–QRT pure drugs to rats at the dose of 5 mg kg−1 each. The results reveal that the developed method can be further used for the quantification of the proposed combination drugs in nanoformulations.

Simultaneous determination of bioactive flavonoids of Hoveniae Semen in rat plasma by LC-MS/MS: Application to a comparative pharmacokinetic study

A selective, sensitive and fully validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was established for the determination of dihydromyricetin, dihydroquercetin, myricetin and quercetin in rat plasma after intragastric administration of Hoveniae Semen total flavonoids. Baicalin was selected as the internal standard. Analytes were extracted from the rat plasma by protein precipitation with acetonitrile and separated on a C18 chromatographic column (Agilent ZORBAX Eclipse Plus, 4.6 mm × 100 mm, 3.5 μm) using the mobile phase containing acetonitrile (A) and 0.1% formic acid-water (B) by gradient elution at 0.5 mL/min flow rate. A tandem mass spectrometer equipped with an electrospray ionization (ESI) source was used to detect analytes. The analytes were measured by multiple reaction monitoring (MRM) in the negative ionization mode. The lower limit of quantification of dihydromyricetin, dihydroquercetin, myricetin and quercetin were 0.70, 8.16, 1.62 and 0.56 ng/mL, respectively. The accuracy, intra-day and inter-day precision and recovery were all satisfactory and the compounds were stable in rat plasma under all tested conditions. The approach was successfully applied to study pharmacokinetic characteristics of the four bioactive flavonoids in plasma after administering Hoveniae Semen total flavonoids intragastrically to rat. Further investigation was carried out to assess pharmacokinetic comparability of the four bioactive flavonoids after intragastric administration of Hoveniae Semen total flavonoids to mixture of flavonoids.

Bioavailability of Quercetin in Humans with a Focus on Interindividual Variation.

After consumption of plant-derived foods or beverages, dietary polyphenols such as quercetin are absorbed in the small intestine and metabolized by the body, or they are subject to catabolism by the gut microbiota followed by absorption of the resulting products by the colon. The resulting compounds are bioavailable, circulate in the blood as conjugates with glucuronide, methyl, or sulfate groups attached, and they are eventually excreted in the urine. In this review, the various conjugates from different intervention studies are summarized and discussed. In addition, the substantial variation between different individuals in the measured quercetin bioavailability parameters is assessed in detail by examining published human intervention studies where sources of quercetin have been consumed in the form of food, beverages, or supplements. It is apparent that most reported studies have examined quercetin and/or metabolites in urine and plasma from a relatively small number of volunteers. Despite this limitation, it is evident that there is less interindividual variation in metabolites which are derived from absorption in the small intestine compared to catabolites derived from the action of microbiota in the colon. There is also some evidence that a high absorber of intact quercetin conjugates could be a low absorber of microbiota-catalyzed phenolics, and vice versa. From the studies reported so far, the reasons or causes of the interindividual differences are not clear, but, based on the known metabolic pathways, it is predicted that dietary history, genetic polymorphisms, and variations in gut microbiota metabolism would play significant roles. In conclusion, quercetin bioavailability is subject to substantial variation between individuals, and further work is required to establish if this contributes to interindividual differences in biological responses.

Simultaneous determination of kaempferol, quercetin, mangiferin, gallic acid, p‐hydroxybenzoic acid and chlorpheniramine maleate in rat plasma after oral administration of Mang‐Guo‐Zhi‐Ke tablets by UHPLC‐MS/MS and its application to pharmacokinetics

Mang-Guo-Zhi-Ke tablets (MGZKTs) is an effective Chinese patent medicine. It contains mango leaf extract as the main raw material and the antihistamine drug, chlorpheniramine maleate is included in the formulation. However, its pharmacokinetic effect is rarely reported. A highly sensitive, reliable and rapid high-throughput method using ultra-high-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) was used to simultaneously determine kaempferol, quercetin, mangiferin, p-hydroxybenzoic acid, gallic acid and chlorpheniramine maleate in rat plasma after oral administration of MGZKTs. The method was successfully developed and fully validated to investigate the pharmacokinetics of MGZKTs. Chloramphenicol and clarithromycin were used as internal standards (IS). A practicable protein precipitation procedure with methanol was adopted for sample preparation. The samples were separated on an Acquity UHPLC Syncronis C18 column (100 × 2.1 mm, 1.7 μm) using 0.1% formic acid-acetonitrile as the mobile phase. The flow rate was set at 0.4 mL/min. The obtained calibration curves were linear in the concentration range of ~1-1000 ng/mL for plasma (r > 0.99). Method validation results met the criteria reported in the US Food and Drug Administration guidelines. Quercetin, p-hydroxybenzoic acid and kaempferol were absorbed rapidly and reached the peak concentration between 0.16 and 0.25 h. This validated that the UHPLC-MS/MS method was successfully applied to study the pharmacokinetic parameters of the six compounds in rat plasma after oral administration of MGZKTs. This evidence will be useful for the clinical rational use of Mang-Guo-Zhi-Ke tablets.

Simultaneous determination of seven bioactive compounds and pharmacokinetics in rat plasma after oral administration of Yindan Xinnaotong Ruanjiaonang by UPLC-MS/MS

To estabish ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for simultaneous determination of quercetin(QCT), isorhamnetin(ISR), kaempferol(KMF), ginkgolide A(GA), ginkgolide B(GB), ginkgolide C(GC) and bilobalide(BB) in rat plasma and investigate the pharmacokinetic process of seven compounds after oral administration of Yindan Xinnaotong Ruanjiaonang, The results indicated that all calibrations curves showed good linearity (r≥0.997 1). RSD of intra-day and inter-day precisions were all within 11%. The matrix effects and extraction recovery were in the range of 93.28%-103.6% and 72.43%-95.77% respectively. The peak concentration (Cmax) of QCT, ISR, KMF, GA, GB, GC and BB were (45.02±11.28), (49.90±13.82), (27.85±8.38), (76.31±18.19), (76.54±15.43), (35.35±10.28), (48.70±12.34) μg•L⁻¹, respectively. The peak time (tmax) of seven constituents were (0.33±0.11), (0.50±0.23), (0.33±0.14), (0.75±0.29), (1.0±0.35), (1.5±0.23), (0.75±0.50) h, respectively. UPLC-MS/MS method established in this research was proved to be so rapid and sensitive that it can be applied to the pharmacokinetic study of seven bioactive constituents in Yindan Xinnaotong Ruanjiaonang.

Development of an ultra-fast liquid chromatography-tandem mass spectrometry method for simultaneous determination of seven flavonoids in rat plasma: Application to a comparative pharmacokinetic investigation of Ginkgo biloba extract and single pure ginkgo flavonoids after oral administration.

For deeper pharmacokinetic investigation and further curative application of ginkgo flavonoids, a delicate, efficient and precise UFLC-MS/MS technique for synchronous quantitation of seven flavonoids, apigenin, luteolin, naringenin, quercetin, diosmetin, kaempferol and isorhamnetin in rat plasma has been established. After mixing with the internal standard (IS) linarin, bio-samples were pretreated via ethyl acetate for liquid-liquid extraction, then isolated at 0.2ml/min flow rate on a Venusil MP C18 chromatographic column (100mm×2.1mm, 3μm) by means of gradient elution. 0.1% formic acid-water and methanol system was used as the mobile phase. Mass spectrometric inspection was conducted on a 4000Q UFLC-MS/MS system with turbo ion spray source in patterns of negative ion and multiple reaction-monitoring (MRM). All calibration curves proved favorable linearity (R2≥0.9918) in linear ranges. Intra-day and inter-day precisions didn't exceed 14.0% for all the analytes, and the accuracy was within 6.9%. Extraction recoveries of analytes and IS were less than ±15.0% of nominal concentrations. This method has been under thorough and firm verification for a comparative pharmacokinetic research after gavage between Ginkgo biloba extract and single pure ginkgo flavonoids. The results demonstrated that there're evident pharmacokinetic discrepancies, and possible structural influences were innovatively proposed. Generally, substitution with 3-hydroxylation, a double bond in ring C, ring B methoxylation often confer longer onset period. The existence of ring B catechol group gives rise to faster clearance.

Two-phase hollow fiber-liquid microextraction based on reverse micelle for the determination of quercetin in human plasma and vegetables samples

A new two-phase hollow fiber-liquid microextraction based on reverse micelle as sensitive and efficient method for the extraction of quercetin in human plasma, onion and tomato samples was developed for the first time. The extraction is based on the solubilization of analyte in the aqueous core of the reverse micelle of cationic cethyltrimethyl ammonium bromide surfactant, CTAB, which are present in the organic phase and are used as acceptor phase in hollow fiber-liquid phase microextraction. Experimental results show that the electrostatic interaction between the oppositely charged surfactant head group present in the reverse micelles and the analyte molecule has a key role in the extraction. Extraction parameters including the organic phase, pH, surfactant concentrations, stirring rate, extraction time, temperature and ionic strength were optimized. The optimum condition is obtained when the variables are set to: pH= 7.5, organic solvent= 1-octanol, CTAB concentration= 7mmolL−1, stirring rate= 900rpm at room temperature and extraction time= 30min. Under the mentioned condition, the calibration range was found to be linear over 0.5–1000ngmL−1 with the limit of detection of 0.1ngmL−1. The extraction recovery of 97.4%, with relative standard deviation of 3.5%, was obtained via tree replicated measurements on a 15ngL−1 quercetin standard solution. Finally, the newly developed method was successfully used for the preconcentration and determination of quercetin in plasma, onion and tomato samples.

Simultaneous Determination and Pharmacokinetic Study of Quercetin, Luteolin, and Apigenin in Rat Plasma after Oral Administration of Matricaria chamomilla L. Extract by HPLC-UV.

A simple and sensitive HPLC-UV method has been developed for the simultaneous determination of quercetin, luteolin, and apigenin in rat plasma after oral administration of Matricaria chamomilla L. extract. The flow rate was set at 1.0 ml/min and the detection wavelength was kept at 350 nm. The calibration curves were linear in the range of 0.11–11.36 μg/ml for quercetin, 0.11–11.20 μg/ml for luteolin, and 0.11–10.60 μg/ml for apigenin, respectively. The intraday and interday precisions (RSD) were less than 8.32 and 8.81%, respectively. The lower limits of quantification (LLOQ) of the three compounds were 0.11 μg/ml. The mean recoveries for quercetin, luteolin, and apigenin were 99.11, 95.62, and 95.21%, respectively. Stability studies demonstrated that the three compounds were stable in the preparation and analytical process. The maximum plasma concentration (Cmax) was 0.29 ± 0.06, 3.04 ± 0.60, and 0.42 ± 0.10 μg/ml, respectively. The time to reach the maximum plasma concentration (Tmax) was 0.79 ± 0.25, 0.42 ± 0.09, and 0.51 ± 0.13 h, respectively. The validated method was successfully applied to investigate the pharmacokinetics study of quercetin, luteolin, and apigenin in rat plasma after oral administration of M. chamomilla extract.

A new validated HPLC method for the determination of quercetin: Application to study pharmacokinetics in rats.

A simple, accurate, and reproducible high-performance liquid chromatography (HPLC) method has been developed and validated for the quantification of quercetin (QR) in rat plasma. The method involves a simple protein precipitation procedure to extract both QR and thymoquinone (TQ), the internal standard. The chromatographic analysis was achieved on a Shimadzu LC 20 A HPLC system equipped with a Supelcosil LC-18 T C18 column and an isocratic mobile phase consisting of 0.3% trichloroacetic acid in water and acetonitrile HPLC-grade (50:50, v/v) run at a flow rate of 0.9 mL/min for 13 min. The UV detection wavelength was set at 254 nm. The method exhibited good linearity (R2 >0.994) over the assayed concentration range (0.10-25 μg/mL) and demonstrated good intra-day and inter-day precision and accuracy (relative standard deviations and the deviation from predicted values were <20%). This method was also successfully applied for studying the pharmacokinetics of QR in rats following a single oral dose of QR to evaluate its pharmacokinetic parameters in rats.

Zein nanoparticles for oral delivery of quercetin: Pharmacokinetic studies and preventive anti-inflammatory effects in a mouse model of endotoxemia

Zein nanoparticles were evaluated as nanocarriers to promote the oral bioavailability of quercetin and, thus, improve its anti-inflammatory effect on a mouse model of induced endotoxemia. For this purpose, the flavonoid and 2-hydroxypropyl-β-cyclodextrin were encapsulated in zein nanoparticles. The resulting nanoparticles displayed a mean size of about 300nm and the payload was calculated to be close to 70μg/mg nanoparticle. The release of quercetin from zein nanoparticles followed a zero-order kinetic. After oral administration, nanoparticles provided high and sustained levels of quercetin in plasma and the relative oral bioavailability was calculated to be approx. 60%. Animals treated with quercetin-loaded nanoparticles (1 dose every two days; 1week) presented endotoxic symptoms less severe than those observed in animals treated with the oral solution of the flavonoid (1 dose every day; 1week). This was further corroborated by the significantly low circulating TNF-alpha in the quercetin-loaded nanoparticles treated mice.

Effects of phospholipid complexes of total flavonoids from Persimmon (Diospyros kaki L.) leaves on experimental atherosclerosis rats

The total flavonoids from Persimmon leaves (PLF), extracted from the leaves of Diospyros kaki L. Dispryosl and Ebenaceae, is reported to possess many beneficial health effects. However, the oral bioavailability of PLF is relatively low due to its poor solubility. In the present study, the phospholipid complexes of total flavonoids from Persimmon leaves (PLF-PC) was prepared to enhance the oral bioavailability of PLF and to evaluate its antiatherosclerotic properties in atherosclerosis rats in comparison to PLF. A HPLC-MS method was developed and validated for the determination of quercetin and kaempferol in rats plasma to assess the oral bioavailability of PLF-PC. The effect of PLF (50mg/kg/d) and PLF-PC (equivalent to PLF 50mg/kg/d) on atherosclerosis rats induced by excessive administration of vitamin D (600,000IU/kg) and cholesterol (0.5g/kg/d) was assessed after orally administered for 4 weeks. The relative bioavailabilities of quercetin and kaempferol in PLF-PC relative to PLF were 242% and 337%, respectively. The levels of total cholesterol (TC), triglyceride (TG), low-density lipoprotein-cholesterol (LDL-C), high-density lipoprotein-cholesterol (HDL-C), apolipoprotein A1 (ApoA1) and apolipoprotein B (ApoB) in serum were measured by an automatic biochemistry analyzer. The morphological changes of aorta were observed with optical microscopy. According to the levels of biochemical parameters in serum and the morphological changes of aorta, PLF-PC showed better therapeutic efficacy compared to PLF. Thus, PLF-PC holds a promising potential for increasing the oral bioavailability of PLF. Moreover, PLF-PC exerts better therapeutic potential in the treatment of atherosclerotic disease than PLF.

Simultaneous Analysis of Quercetin and Naringenin in Rat Plasma by Liquid Chromatography-Tandem Mass Spectrometry: Application to a Pharmacokinetic Study After Oral Administration.

A rapid and specific LC-MS-MS method has been developed for simultaneous analysis of quercetin and naringenin in rat plasma. The method was applied to the pharmacokinetics studies of quercetin and naringenin after oral administration of Pollen Typhae extract. The samples were prepared by the protein precipitation method. The analysis was carried out on an ACQUITY UPLC™ BEH C18 column with gradient elution using mobile phase, which included acetonitrile and water (containing 0.1% formic acid). The flow rate was 0.4 mL/min. All analytes including internal standard (IS) were monitored by selected reaction monitoring with an electrospray ionization source. Linear responses were obtained for quercetin ranging from 0.5 to 100 ng/mL and naringenin ranging from 5 to 1000 ng/mL. The intra- and interday precisions (RSD) were less than 10.78 and 11.20%. The extraction recovery of the analytes was acceptable. Stability studies showed that quercetin and naringenin were stable in the preparation and analytical process. The validated method was successfully used to determine the concentration-time profiles of quercetin and naringenin.

Stability indicating simplified HPLC method for simultaneous analysis of resveratrol and quercetin in nanoparticles and human plasma

Resveratrol and quercetin are well-known polyphenolic compounds present in common foods, which have demonstrated enormous potential in the treatment of a wide variety of diseases. Owing to their exciting synergistic potential and combination delivery applications, we developed a simple and rapid RP-HPLC method based on isosbestic point detection. The separation was carried out on phenomenex Synergi 4μ Hydro-RP 80A column using methanol: acetonitrile (ACN): 0.1% phosphoric acid (60:10:30) as mobile phase. The method was able to quantify nanograms of analytes simultaneously on a single wavelength (269nm), making it highly sensitive, rapid as well as economical. Additionally, forced degradation studies of resveratrol and quercetin were established and the method’s applicability was evaluated on PLGA nanoparticles and human plasma. The analytes peaks were found to be well resolved in the presence of degradation products and excipients. The simplicity of the developed method potentializes its suitability for routine in vitro and in vivo analysis of resveratrol and quercetin.

Simultaneous determination and pharmacokinetic study of eight components in rat plasma by UHPLC-MS/MS after oral administration of Hypericum japonicum Thunb extract

A rapid and sensitive assay based on ultra high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) was established and validated for the simultaneous determination of gallic acid, protocatechuic acid, vanillic acid, caffeic acid, epicatechin, isoquercitrin, vincetoxicoside B and quercetin in rat plasma using catechin and daidzein as the internal standards (IS). Plasma samples added internal standards were acidified with formic acid then pretreated by direct protein precipitation with acetonitrile. The separation of eight constituents was achieved on a C18 column with gradient elution using methanol and 0.2% acetic acid aqueous solution as the mobile phase and detected by multiple reaction monitoring using electrospray ionization source in the positive–negative ionization mode. The method was validated for sufficient specificity, precision, accuracy, and sensitivity over the concentration range of 10–6000ngmL−1 for gallic acid, 1.5–3000ngmL−1 for protocatechuic acid, 10–15000ngmL−1 for vanillic acid, 2–3600ngmL−1 for caffeic acid, 1.5–3600 ngmL−1 for epicatechin, 4–6000ngmL−1 for isoquercitrin, 2–9000ngmL−1 for vincetoxicoside B, and 20–18000ngmL−1 for quercetin. The overall intra‑run precision and the inter‑run precision were showed in the range of 1.0–14.2% and 2.8–12.9%, respectively, and the accuracy was no more than 12.8%. This analytical method was successfully applied to investigate the pharmacokinetics of eight ingredients in rats after oral administration of Hypericum japonicum Thunb extract.

Simultaneous Determination of Flavonols and Terpene Lactones in Beagle Dog Plasma by Ultra-Performance Liquid Chromatography-Tandem - Mass Spectrometry: 1. Method Development

Purpose: To develop an ultra-performance liquid chromatography-tandem mass spectrometry (UPLCMS/MS) method for the simultaneous determination of 7 major components of Ginkgo leaf (kaempferol, quercetin, isorhamnetin, ginkgolides A, ginkgolides B, ginkgolides C and bilobalide) in dog plasma. Methods: Beagle dog plasma samples were spiked with internal standard (domperidone), acidified with HCl and extracted twice by liquid-liquid extraction using ethyl acetate. Chromatographic separation was achieved on an Acquity UPLC BEH C18 column (100 x 2.1 mm, 1.7 μm) by gradient elution with a run time of 4.0 min. The specificity, linearity, precision, recovery, matrix effect and stability of the method were determined.Results: The method showed high selectivity of the flavonols and terpene lactones in plasma samples. The concentration of the 7 target compounds showed good linear relationship with the peak area ratios of each analyte to internal standard. Lower limit of quantification (LLOQ) was 1.232, 0.240, 0.200, 1.330, 0.960, 0.696, 0.470 ng•mL-1 for kaempferol, quercetin, isorhamnetin, bilobalide, ginkgolides A, ginkgolides B and ginkgolides C, respectively. Recovery of all QC samples ranged from 77.68 to 105.07 %. Matrix effect derived from QC samples was in the range of 85.09 – 113.14 %. The stability of the analytes, calculated as RSD at three concentrations, was &lt; 15 %.Conclusion: The developed method is simple, rapid and sensitive and can be applied to the determination of kaempferol, quercetin, isorhamnetin, ginkgolides A, ginkgolides B, ginkgolides C and bilobalide in dog plasma.Keywords: Ultra-performance liquid chromatography-tandem mass spectrometry, Ginkgo biloba, Beagle dog plasma, Kaempferol, Quercetin, Isorhamnetin, Ginkgolides A, Ginkgolides B, Ginkgolides C, Bilobalide