Rat Plasma Extracts Research Articles

Simultaneous determination of five constituents of areca nut extract in rat plasma using UPLC-MS/MS and its application in a pharmacokinetic study

Areca nuts have been used as a traditional Chinese medicine (TCM) for thousands of years. Recent studies have shown that it exhibits good pharmacological activity and toxicity. In this study, the pharmacokinetics of five major components of areca nut extract in rats were investigated using a highly sensitive ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UPLC-MS/MS) method. Arecoline, arecaidine, guvacoline, guvacine, and catechin were separated and quantified accurately using gradient elution with mobile phases of (A) water containing 0.1 % formic acid-10 mM ammonium formate, and (B) methanol. The constituents were detected under a timing switch between the positive and negative ion modes using multiple reaction monitoring (MRM). Each calibration curve had a high R2 value of >0.99. The method accuracies ranged −7.09–11.05 % and precision values were less than 14.36 %. The recovery, matrix effect, selectivity, stability, and carry-over of the method were in accordance with the relevant requirements. It was successfully applied for the investigation of the pharmacokinetics of these five constituents after oral administration of areca nut extract. Pharmacokinetic results indirectly indicated a metabolic relationship between the four areca nut alkaloids in rats. For further clarification of its pharmacodynamic basis, this study provided a theoretical reference.

Simultaneous Determination of 5 Active Components of Periploca forrestii Schltr Extract in Rat Plasma by UPLC-MS and Its Application to Pharmacokinetic Studies in Normal and Adjuvant-Induced Arthritis Model Rats

Periploca forrestii Schltr ( P. forrestii) is a herb used in traditional Chinese medicine for its anti-rheumatoid arthritis effect. The aim of this study was to compare the pharmacokinetic properties of the 5 active components of this plant: neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, isochlorogenic acid C, and periplocin between normal rats and adjuvant-induced arthritis model rats. After the intravenous administration (177.78 mg/kg) of P. forrestii extract, samples were analyzed by ultra-performance liquid chromatography-tandem mass spectrometry. Compared with normal rats, the area under the curve [(AUC)(0-t), AUC(0-∞)], mean residence time [(MRT)(0-t), MRT(0-∞)] of neochlorogenic acid-treated rats decreased significantly, and drug clearance (CL) and apparent volume of distribution (V) increased significantly; the V of chlorogenic acid-treated rats decreased significantly, and MRT(0-t) significantly increased; the AUC(0-t) and AUC(0-∞) of cryptochlorogenic acid-treated rats decreased significantly, and CL and V increased significantly; the AUC(0-t) and MRT(0-t) of isochlorogenic acid C-treated rats decreased significantly, and V increased significantly; the AUC(0-t) and AUC(0-∞) of periplocin-treated rats increased significantly, and MRT(0-t), MRT(0-∞), CL, and V decreased significantly in model rats. The disease condition of rheumatoid arthritis in rats had a significant effect on the in vivo pharmacokinetics of P. forrestii after the intravenous administration.

Simultaneous determination of eight bioactive components in Marsdenia tenacissima extract in rat plasma by LC-MS/MS and its application in a pharmacokinetic study.

As a traditional Chinese medicine, Marsdenia tenacissima (Roxb.) Wight et Arn. plays an indispensable role in clinical practice owing to its specific efficacy in treating malignant tumors, leukocythemia, cystitis and asthma. This study aimed to establish a novel and scientific LC-MS/MS approach to simultaneously determine tenacissoside B, H, G and I, caffeic acid, cryptochlorogenic acid, chlorogenic acid and neochlorogenic acid from M. tenacissima extract within the rat plasma samples. Digoxin was used as the internal reference. All determinations were carried out using the Eclipse Plus C18 column, and water (containing 0.1% formic acid) was used as the mobile phase A, while acetonitrile was the mobile phase B for gradient elution. The UPLC methods were validated, including calibration curves, accuracy, precision, stability and recovery of the total eight analytes, in accordance with the requirements for biopharmaceutical analysis. Moreover, the proposed approach was also used in comprehensive pharmacokinetic research on those eight analytes in rats following M. tenacissima extract gavage. According to the pharmacokinetic parameters, tenacissoside B, I, H and G are the long-acting and primary bioactive constituents in M. tenacissima extract, with long mean residence times and high concentrations. Our findings shed light on the absorption mechanism and provide significant information for the clinical application of M. tenacissima.

Simultaneous Determination of Four Iridoid Glycosides from Paederia Scandens in Rat Plasma by LC-MS/MS and its Application to a Pharmacokinetic Study

Background: Paederia scandens (Lour.) Merrill, belonging to the Rubiaceae family, was one of the Traditional Chinese Medicines that has been generally used to treat aches and pains, inflammation, bacillary dysentery, piles and rheumatic arthritis. The four iridoid glycosides that Paederosidic acid, Paederoside, Paederosidic acid methyl ester, and Asperuloside from Paederia scandens are considered to be the main bioactive constituents. However, their pharmacokinetics and action mechanisms of these iridoid glycosides still remain unknown. In this study, a method of simultaneous determination of four iridoid glycosides components in rat plasma with LC-MS/MS has been established and successfully applied to a pharmacokinetic study in rats, which would be favourable for further exploration. Methods: In this study, a sensitive, rapid, accurate bioanalytical method of simultaneous determination of four iridoid glycosides components from Paederia scandens extract in rat plasma with LCMS/ MS has been established. It is easy and rapid for LC-MS/MS to accurately separate and simultaneously quantify the analytes because of its high sensitivity, selectivity and accuracy. This validated method was successfully applied to a pharmacokinetic study in rats with intravenous and oral administrations of Paederia scandens extract. Results: The resulting data are fully satisfied for the selectivity and the sensitivity. Their lower limit of quantitation are in 0.25-0.5 ng/mL. Intra- and interday precisions were less than 15.0% with accuracy in the range of -15.0% to 15.0%. In the stability measurements including repeated Freeze-thaw, 4 hours at 4°C, 24 hours at 4°C, and 30 days at -80°C, the variations between the measurements and the nominated values of these compounds in plasma were detected to be less than 15.0%. The extraction recoveries of the compounds were from 85.4% to 105.6%. The bioavailability (F) of the four iridoid glycosides were 1.74% to 3.36%. Conclusion: In summary, a simple, rapid, precise, and sensitive LC-MS/MS method has been established and validated to determine the four iridoid glycosides from Paederia scandens extract in rat plasma, which was successfully applied to pharmacokinetic study in rats. The information obtained from the study will facilitate further exploration on Paederosidic acid, Paederoside, Paederosidic acid methyl ester as well as Asperuloside and these may provide valuable pharmacokinetic reference for human applications.

Simultaneous Determination of Five Components of Laportea bulbifera Extract in Rat Plasma by LC-MS/MS: Application to a Pharmacokinetic Study

Laportea bulbifera (Siebold & Zucc.) Wedd., Urticaceae, is a medicinal herb customarily used by the Miao people in China, for the treatment of rheumatism, traumatic injury, and other symptoms. The aim of this study was to develop and validate a sensitive and reliable high-performance liquid chromatography-tandem mass spectrometry method for the simultaneous quantitation of five constituents, including neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, rutin, and kaempferol-3-O-rutinoside, of L. bulbifera extract in biological samples, and to apply the method to a pharmacokinetic study. The validated method was successfully applied to a pharmacokinetic study in rats with oral administration of L. bulbifera extract at a single dose of 8.3 g kg−1. The five constituents were detected and their pharmacokinetic parameters were calculated. The established method was rapid and sensitive and could be used for the pharmacokinetic study of L. bulbifera extract.

Characterization and identification of the metabolites of Menthae Haplocalycis Herba water extracts in rat plasma, urine, and feces by ultra-high performance liquid chromatography with linear ion trap-Orbitrap mass spectrometry.

Menthae Haplocalycis Herba has been utilized for food and medicinal purposes in China for thousands of years. It has various efficacies, including dispelling wind and heat and relieving sore throat. M. Haplocalycis Herba has been also widely used in food, cosmetics, spices, and other fields. Exploring the constituents and detecting the metabolites of M. Haplocalycis are of great significance to clarify the effective substances. However, the in vivo metabolites of M. Haplocalycis Herba water extract are still unclear. Herein, a sensitive and specific method, ultra-high performance liquid chromatography with linear ion trap-Orbitrap mass spectrometry, established in this assay was used to study the metabolism of M. Haplocalycis Herba water extract in rat plasma, urine, and feces. We characterized and identified 9, 50, and 34 metabolites in plasma, urine, and feces, respectively. Seven metabolic pathways, including phase Ⅰ (isomerization, demethylation, hydroxylation, and dehydration) and phase Ⅱ (sulfation and glucuronidation) were mainly involved in the metabolism. It is the first systematic study on the metabolism of M. Haplocalycis Herba water extract in vivo, which enrich current understanding of the metabolic behavior of M. Haplocalycis Herba water extract and provide a metabolic rationale for further in-depth in vivo biotransformation and pharmacokinetic analysis.

Bioactive indanes: Development and validation of an LC-MS/MS bioanalytical method for the determination of PH46A, a new potential anti-inflammatory agent, in dog and rat plasma and its application to a pharmacokinetic study in dog

A new chemical entity, which is a chiral indane dimer, PH46A, has been developed by our research group. As a clinical candidate. PH46A has recently completed Phase I clinical studies in man. Previously, during its pre-clinical development, in in vivo pre-clinical studies PH46A showed potent anti-inflammatory properties, which can be targeted at a range of diseases, including inflammatory bowel disease (IBD). To support the pre-clinical development of this drug candidate, we developed a LCMS/MS method for determining PH46 (the acid form of PH46A salt) in both dog and rat plasma using Compound 1 as internal standard (IS). Those species were selected for safety pharmacology and toxicology, as well as pharmacokinetics studies.The method was validated over the range 10−10000 ng/mL for both matrices and the linearity, accuracy, precision and specificity over this range were demonstrated to be acceptable. No significant matrix effects or carryover were observed for both PH46 and IS and recovery was consistent. PH46 was found to be stable in both dog and rat plasma under the test conditions, such as at room temperature for >24 h, through 3 freeze/thaw cycles, and at -20 °C for >1 month. PH46 and IS in dog and rat plasma extracts were also found to be stable in the autosampler against fresh standard extracts on re-injection after 143.5 h and 243.5 h, respectively at 4 °C. 10- and 100-fold dilutions with control matrix were found not to affect the performance of the assay. This method was successfully applied to a pharmacokinetic study in the dog. With the exception of one dog, 003 M, oral administration of PH46A in gelatine capsules was well tolerated at a dose level of 100 mg/kg. The highest Cmax was observed in animal 003 M. The rapid absorption and high plasma concentration observed for animal 003 M compared to the data for animals 001 M and 002 M may account for the sickness observed in this animal; however, the reasons for this have not been investigated.

An ultra high performance liquid chromatography with tandem mass spectrometry method for simultaneous determination of thirteen components extracted from Radix Puerariae in rat plasma and tissues: Application to pharmacokinetic and tissue distribution study.

A rapid and sensitive ultra high performance liquid chromatography with tandem mass spectrometry method was established and validated for simultaneous determination of thirteen bioactive components (gallic acid, protocatechuic acid, puerarin, p-hydroxycinnamic acid, daidzin, ononin, daidzein, naringenin, genistein, apigenin, formononetin, biochanin A, and β-sitosterol) of Radix Puerariae extract in rat plasma and tissues. The plasma and tissues samples were pretreated by protein precipitation extraction, and umbelliferone and rutin were used as internal standards. Sample separation was performed on a ZORBAX RRHD Eclipse plus C18 column (2.1mm × 50mm, 1.8µm, Agilent) with a mobile phase consisting of methanol-water (containing 0.1% formic acid). The mass spectrometry analysis was conducted in positive and negative ionization modes with multiple reaction monitoring. The lower limit of quantitation range for the 13 analytes was 0.2-35ng/mL. The intra- and inter-day precision of all the analytes were less than 10.92%, with an accuracy ranging from -13.10 to 11.96%. Both the recovery and matrix effect were within acceptable limits. This method was successfully applied to pharmacokinetic and tissue distribution study of the 13 bioactive components in rats after oral administration of R. Puerariae extract.

Simultaneous Determination of Five Alkaloids by HPLC-MS/MS Combined With Micro-SPE in Rat Plasma and Its Application to Pharmacokinetics After Oral Administration of Lotus Leaf Extract.

An environment-friendly and efficient method for simultaneous determination of five alkaloids (nunciferine, O-nornuciferin, liriodenine, armepavine, and pronuciferine) in rat plasma was established by HPLC-MS/MS associated with micro-solid phase extraction (micro-SPE). The plasma sample was pretreated by using micro-SPE columns filled with polymer materials PEP-2 and eluted by little organic solvent (400 µl acetonitrile). The five alkaloids were separated with acetonitrile and 0.1% formic acid aqueous solution on Eclipse plus C18 column. The mode of positive electrospray ionization was used to measure the analytes in multiple-reaction monitoring (MRM). The determination coefficients (R2) of the five alkaloids were greater than 0.99. The lower limit of quantification (LLOQ) of O-nornuciferin, liriodenine, and armepavine was 0.5 ng·ml−1, and that of nunciferine and pronuciferine was 1 ng·ml−1. The validated method was effectively used for the pharmacokinetics of the five orally administrated alkaloids of lotus leaf extract in rat plasma.

Simultaneous Quantification and Pharmacokinetic Study of Nine Bioactive Components of Orthosiphon stamineus Benth. Extract in Rat Plasma by UHPLC-MS/MS.

Orthosiphon stamineus Benth. (OS) is a traditional folk medicine for the treatment of kidney stones and other urinary tract diseases. In this study, a rapid and sensitive Ultra high-performance liquid chromatography (UHPLC)-MS/MS approach was established and validated for the simultaneous quantification of nine bioactive components in rat plasma. The nine components from OS extract detected in rat plasma were danshensu, protocatechuic acid, caffeic acid, rosmarinic acid, salvianolic acid A, salvianolic acid B, cichoric acid, sinensetin and eupatorin. After liquid-liquid extraction with ethyl acetate, the plasma samples were subjected to a triple quadrupole mass spectrometer employing electrospray ionization (ESI) technique and operating in multiple reaction monitoring (MRM) with both positive and negative ion modes. The standard curves showed good linear regression (r > 0.9915) over the concentration range for the nine analytes. The inter-day and intra-day precision and accuracy were found to be within 15% of the nominal concentration. The recovery and stability of nine compounds were all demonstrated to be within acceptable limits. The approach was successfully applied to investigate the pharmacokinetic analysis of the nine bioactive components after oral administration of OS extract in rats.

Validated UHPLC–MS/MS method for simultaneous determination of four triterpene saponins from Akebia trifoliata extract in rat plasma and its application to a pharmacokinetic study

Saponin PH, akemisaponins E, saponin PJ1 and scheffoleoside A, the main bioactive triterpene saponins of Chinese traditional medicine Akebia trifoliata, contribute to its diuretic pharmacological activity. Because of interactions of the multiple ingredients in vivo, pharmacokinetic studies of multiple triterpenes after administration of A. trifoliata extract are essential to clarify their pharmacological effects. The purpose of this study was to develop an efficient and sensitive UHPLC-MS/MS method for simultaneous determination of these four triterpene saponins in rat plasma. The biosamples were prepared by liquid-liquid extraction with n-butanol. The chromatographic separation was performed on a Phenomenex Luna® C18 (150 × 2 mm, 3 μm) with a mobile phase consisting of acetonitrile and water at a flow rate of 0.5 mL/min. The MS/MS system was operated in a negative multiple reaction monitoring mode, and the precursor-product ion transitions were optimized as m/z 941.6 → 471.1 for saponin PH, 941.7 → 471.2 for akemisaponins E, 1089.7 → 601.1 for saponin PJ1 , 957.6 → 487.4 for scheffoleoside A and 799.5 → 637.3 for ginsenoside Rg1 (Rg1 , internal standard). Method validation parameters (calibration curve linearity, lower limit of detection, recovery, matrix effect, intra- and inter-day precision) were within the acceptable ranges. This is the first reported on the UHPLC-MS/MS detection of saponin PH, akemisaponins E, saponin PJ1 and scheffoleoside A, and applied to a preclinical pharmacokinetic study after oral administration of A. trifoliata extract in rats. This study provides a basis for clinical application and further development of A. trifoliata extract.

Simultaneous determination of major components of Huangqi-Honghua extract in rat plasma using LC-MS/MS and application to a pharmacokinetic study.

A sensitive and reliable LC-MS/MS method was developed and validated for simultaneous quantification of the major components of Huangqi-Honghua extact in rat plasma, including hydroxysafflor yellow A (HSYA), astragaloside IV (ASIV), calycosin-7-O-β-d-glucoside (CAG), calycosin, calycosin-3'-O-glucuronide (C-3'-G) and calycosin-3'-O-sulfate (C-3'-S). After extraction by protein precipitation with acetonitrile and methanol from plasma, the analytes were separated on a Hypersil BDS C18 column by gradient elution with acetonitrile and 5 mM ammonium acetate. The detection was carried out on a triple quadrupole tandem mass spectrometer equipped with electrospray ionization source switched between negative and positive modes. HSYA was monitored in negative ionization mode from 0 to 4.9 min, and ASIV, CAG, calycosin, C-3'-G and C-3'-S were determined in positive ionization mode from 4.9 to 10 min. The lower limits of quantification of the analytes were 6.25 ng/mL for HSYA, 0.781 ng/mL for CAG and 1.56 ng/mL for ASIV and calycosin. The intra- and inter-assay precision (RSD) values were within 13.43%, and accuracy (RE) ranged from -8.75 to 9.92%. The validated method was then applied to the pharmacokinetic study of HSYA, ASIV, CAG, calycosin, C-3'-G and C-3'-S in rat after an oral administration of Huangqi-Honghua extract.

Simultaneous Determination of Five Chromones of Radix Saposhnikoviae Extract in Rat Plasma by UPLC-MS/MS: Application to a Comparative Pharmacokinetic Study in Normal and Febrile Rats.

A rapid and sensitive quantitative analytical method was established for the simultaneous determination of five chromones (prim-O-glucosylcimifugin, cimifugin, 4′-O-β-D-glucosyl-5-O-methylvisamminol, 5-O-methylvisammiol, and sec-o-glucosylhamaudol) in the plasma of RS-treated rats for the first time using ultra performance liquid chromatography- (UPLC-) tandem mass spectrometry. The Waters Acquity UPLC BEH C18 (50 mm × 2.1 mm, 1.7 μm) was used as the chromatographic column, 0.1% formic acid water and 0.1% formic acid acetonitrile comprised the mobile phases, and all samples were determined under positive ion mode. The results showed that all analytes had good linearity (r > 0.9902), between-day and within-day precisions less than 15%, accuracy between −5.50% and 5.53%, and extraction recovery between 88.26% and 97.65%. Both the matrix effect and stability met the requirements. This method was successfully applied for the comparative pharmacokinetics of five active components of RS in normal and febrile rats. The results showed that the pharmacokinetic behavior of RS extract significantly differed between the two types of rats.

High resolution UPLC-MS/MS method for simultaneous separation and determination of six flavonoids from semen cuscutae extract in rat plasma: application to comparative pharmacokinetic studies in normal and kidney-deficient rats

Semen Cuscutae, which mainly consisted of flavonoids, is a traditional Chinese herbal medicine and used for nourishing the liver and kidneys. The aim of this study was to develop a sensitive and selective UPLC-MS/MS method for simultaneous separation and determination of six main active renoprotective components of Hyperoside, Astragalin, Isoquercitrin, Quercitrin, Quercetin, and Kaempferol from Semen Cuscutae in rat plasma, and to reveal the pharmacokinetic differences between normal and kidney deficient rats. The validated method has been successfully applied to comparing pharmacokinetic profiles of the six analytes in rat plasma. The results indicated that there was significant difference in pharmacokinetic parameters of the six analytes between two groups, while absorptions in kidney deficient group were significantly lower than those in normal group. This study would be helpful for evaluating the Semen Cuscutae as renoprotective drug candidates for pre-clinical and clinical research.

A UHPLC-QTOF-MS/MS method for the simultaneous determination of eight triterpene compounds from Poria cocos (Schw.) Wolf extract in rat plasma: Application to a comparative pharmacokinetic study

Poria cum Radix Pini (PRP), White Poria (WP), Rubra Poria (RP), and Poriae Cutis (PC), different parts of the dried sclerotium of Poria cocos (Schw.) Wolf (PCW), have possessed various pharmacological effects and clinical application. In the present study, a novel ultra-high performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS/MS) method was developed and validated for the simultaneous determination of eight triterpene compounds in rat plasma and then was applied in the comparison of pharmacokinetic characteristics of PRP, WP, RP, and PC extracts. Chromatographic separation was performed on an ACQUITY UPLC® BEH C18 (2.1 × 100 mm, 5 μm) with a mobile phase composed of aqueous solution (containing 0.5‰ formic acid and 0.5 mmol/L ammonium acetate) and acetonitrile in gradient elution. Mass spectrometric of the analytes and internal standard (IS) were conducted in negative electrospray ionization with high-resolution multiple reaction monitoring (MRMHR) mode. The lower limit of quantification (LLOQ) for the eight analytes were in the range of 2.00–20.16 ng/mL. All calibration curves showed good linearity (r > 0.993). The inter- and intra-batch precision and accuracy for the eight triterpene compounds were acceptable. The results indicated that the eight triterpene compounds displayed different pharmacokinetic characteristics in PRP, WP, RP, and PC, and that poricoic acid B, poricoic acid A, pachymic acid, dehydrotrametenolic acid, dehydrotumulosic acid, polyporenic acid C and dehydropachymic acid may be the major bioactive compounds of PCW contributing to the diuretic effect.

Stereoselective and Simultaneous Analysis of Ginsenosides from Ginseng Berry Extract in Rat Plasma by UPLC-MS/MS: Application to a Pharmacokinetic Study of Ginseng Berry Extract.

The role of ginseng berry extract (GBE) has been attributed to its anti-hyperglycemic effect in humans. However, the pharmacokinetic characteristics of GBE constitutes after oral GBE administration have not been established yet. In this study, stereoselective and simultaneous analytical methods for 10 ginsenosides (ginsenoside Rb1, Rb2, Rc, Rd, Re, Rg1, S-Rg2, R-Rg2, S-Rg3, and R-Rg3) were developed using ultra-performance liquid chromatography, coupled with electrospray ionization triple quadrupole tandem mass spectrometry (UPLC-MS/MS), for the pharmacokinetic study of GBE. Furthermore, the pharmacokinetic profiles of 10 ginsenosides after oral GBE were evaluated in rats. All analytes were detected with a linear concentration range of 0.01–10 µg/mL. Lower limits of detection (LLOD) and quantification (LLOQ) were 0.003 and 0.01 µg/mL, respectively, for all 10 ginsenosides. This established method was adequately validated in linearity, sensitivity, intra- and inter-day precision, accuracy, recovery, matrix effect, and stability. Relative standard deviations for all intra- and inter-precision of the 10 ginsenosides were below 11.5% and accuracies were 85.3–111%, which were sufficient to evaluate the pharmacokinetic study of oral GBE in rats. We propose that Rb1, Rb2, Rc, Rd, Re, Rg1, S-Rg2, R-Rg2 and/or S-Rg3 were appropriate pharmacokinetic markers of systemic exposure following oral GBE administration.

Comprehensive investigation of in-vivo ingredients and action mechanism of iridoid extract from Gardeniae Fructus by liquid chromatography combined with mass spectrometry, microdialysis sampling and network pharmacology

Gardeniae Fructus is a widely used Traditional Chinese Medicines in treating various diseases. However, the absorbed components and metabolites of its main bioactive iridoid ingredients from iridoid extract of the fruits of Gardeniae Fructus in rat plasma need further study. In this study, a systematic method based on ultra-performance liquid chromatography-quadrupole-time-of-flight/mass spectrometry (UPLC-Q-TOF/MS) technique was developed to speculate the absorbed components and metabolites of iridoid extract in rat plasma after oral administration. A total of 19 compounds, including 9 prototype components and 10 metabolites were identified in plasma. 5 metabolites containing 4 new metabolites (M1, M2, M7, M10) were tentatively determined in rat plasma. Besides, Microdialysis-intensity-fading mass spectrometry (MD-IF-MS) method was originally employed to reveal the binding affinities with α-glucosidase for in-vivo prototype components and their metabolites. Finally, the absorbed constituents and the corresponding target proteins were used to generate compound-target network to find the related diseases and action pathways by a network pharmacology method. The results provide useful information for further study of pharmacology and in vivo mechanism of action of iridoid extract from the fruits of Gardeniae Fructus.

Systematic study on metabolism and activity evaluation of Radix Scutellaria extract in rat plasma using UHPLC with quadrupole time-of-flight mass spectrometry and microdialysis intensity-fading mass spectrometry.

Radix Scutellaria is a widely used traditional Chinese medicine in the treatment of various diseases. However, the activities of the absorbed components and metabolites of its main flavones in rat plasma need further investigation. In this study, a systematic method based on ultra-high performance liquid chromatography with quadruple time-of-flight mass spectrometry was developed to speculate the absorbed components and metabolites of the main flavonoids in Radix Scutellaria extract in rat plasma sample after oral administration of the extract. Twelve compounds, including four prototype components and eight metabolites, were confirmed in drug-containing plasma. In these metabolites, five were originally detected in rat plasma. The possible metabolic pathways of these polyhydroxy flavones in vivo were described and clarified. Microdialysis with intensity-fading mass spectrometry was originally employed to investigate the binding affinities of the absorbed components and metabolites with α-glucosidase. The order of their binding affinities was P4>P3>P2>P1≥M5>M3>M1. The research result is helpful to deepen the understanding of the absorbed components and metabolic pathways of main flavones from Radix Scutellaria, and provide a new approach to screen potential inhibitors from in vivo components originated from Chinese herb.

A UHPLC–MS/MS method for simultaneous determination of twelve constituents from Erigeron breviscapus extract in rat plasma: Application to a pharmacokinetic study

A rapid, sensitive and specific ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated to simultaneously determine the twelve major bioactive ingredients (neochlorogenic acid, chlorogenic acid, caffeic acid, cynarin, scopoletin, scutellarin, isochlorogenic acid A, apigenin-7-o-glucuronide, isochlorogenic acid C, scutellarein, luteolin, and apigenin) in rat plasma. Gallic acid and wogonoside were used as internal standards (IS1 and IS2). The plasma samples were pretreated and extracted by liquid-liquid extraction and protein precipitation with ethyl acetate-acetonitrile (95:5, v/v). Chromatographic separation was accomplished on Agilent ZORBAX RRHD Eclipse Plus C18 column (2.1mm×50mm, 1.8μm) utilizing 0.1% formic acid aqueous solution and acetonitrile as mobile phase under gradient conditions at a flow rate of 0.3mL·min-1. Mass spectrometric detection was performed in multiple reaction monitoring (MRM) mode using electrospray ionization (ESI) in positive and negative mode. The whole intra- and inter-day precision (as relative standard deviation) of all analytes were less than 11.03%, and the accuracy (as relative error) were in the range from -10.43% to 9.76% and from -10.14% to 10.33%. The lower limits of quantification (LLOQ) were 20, 3.0, 100, 7.0, 0.30, 2.0, 70, 1.0, 20, 30, 10, and 2.0ngmL-1 for neochlorogenic acid, chlorogenic acid, caffeic acid, cynarin, scopoletin, scutellarin, isochlorogenic acid A, apigenin-7-o-glucuronide, isochlorogenic acid C, scutellarein, luteolin, and apigenin, respectively. Extraction recovery, matrix effect and stability were found to be the required limits. This method was selective and sensitive for the investigation of the pharmacokinetics of twelve constituents following oral administration to research study about in Erigeron breviscapus of clinical practices for separately analytes on rats.

Selective separation and identification of metabolite groups of Polygonum cuspidatum extract in rat plasma using dispersion solid-phase extraction by magnetic molecularly imprinted polymers coupled with LC/Q-TOF-MS

In this work, magnetic molecularly imprinted polymers (MMIPs) were successfully prepared for specific recognition and selective enrichment of metabolite groups of Polygonum cuspidatum extract in rat plasma.