Quantification of mangiferin in streptozotocin-induced diabetic rat plasma using UPLC-MS/MS: Pharmacokinetic assessment of Gentiana rhodantha extract after oral administration.

Mangiferin, a key bioactive constituent in Gentiana rhodantha, has a favorable impact on reducing blood sugar. A selective and sensitive UPLC MS/MS approach was developed for determining mangiferin in diabetic rats. Employing acetonitrile protein precipitation, chromatographic separation utilized a 2.1×50 mm, 3.5µm C18 column with a mobile phase of 0.1% formic acid aqueous and 5mM ammonium acetate (A, 45%) and acetonitrile (B, 55%) at a 0.5mL min-1 flow rate. Quantification, employing the multiple reaction monitoring (MRM) mode, focused on precursor-to-product ion transitions at m/z 447.1→271.1 for baicalin m/z and 421.0→301.0 for mangiferin. Calibration curves demonstrated linearity in the 1.00~100ng/mL range, with a lower quantification limit for rat plasma set at 1.00ng/mL. Inter- and intra-day accuracies spanned -9.1% to 8.5% and mangiferin mean recovery varied from 82.3% to 86.7%. The adeptly utilized UPLC-MS/MS approach facilitated the exploration of mangiferin pharmacokinetics in diabetic rats.

Determination of 21 photoinitiators in human plasma by using high-performance liquid chromatography coupled with tandem mass spectrometry: A systemically validation and application in healthy volunteers.

In the present study, a comprehensive and sensitive method for simultaneous determination of 21 PIs (nine benzophenones, eight amine co-initiators, and four thioxanthones) in human plasma using high-performance liquid chromatography coupled with tandem mass spectrometry was developed and validated. Two different pre-treatment approaches (liquid-liquid extraction (LLE) and LLE coupled with solid-phase extraction (SPE)) and eight extraction solvents were studied to optimize sample treatment to obtain good recoveries and reduce any matrix effects. The procedure of LLE+SPE was selected as final sample treatment procedure because it obtained higher recoveries as well as lower matrix effects than that performed by LLE alone. The recoveries of 21 target analytes at three spiked concentrations (0.05, 0.5, and 5 ng/mL) ranged from 81% to 109%. The intra- and inter-day relative standard deviations were between 2.5% and 13%. Accuracy and precision data indicated that the detection method was accurate and precise for most of the PIs. The linearities of the labeled dilution calibration curves at 10 concentration levels (iLOQ to 100 ng/mL or iLOQ to 200 ng/mL) were good with correlation coefficients ranged from 0.995 to 0.999. The method quantification limits were in the range of 1.7-16 pg/mL. The analytical method was applied to the analysis of PIs in 14 human plasma samples collected from pregnant women in Guangdong Province, China. Fifteen PIs were detected with total concentrations ranging from 318 to 2772 pg/mL. The ubiquitous contamination of human plasma with PIs suggests that there is widespread exposure to these compounds. Consequently, there should be increased awareness of these pollutants in the environment.

Pharmacokinetic and metabolomic analyses of Mangiferin calcium salt in rat models of type 2 diabetes and non-alcoholic fatty liver disease.

BACKGROUND: Non-alcoholic fatty liver is one of the most common comorbidities of diabetes. It can cause disturbance of glucose and lipid metabolism in the body, gradually develop into liver fibrosis, and even cause liver cirrhosis. Mangiferin has a variety of pharmacological activities, especially for the improvement of glycolipid metabolism and liver injury. However, its poor oral absorption and low bioavailability limit its further clinical development and application. The modification of mangiferin derivatives is the current research hotspot to solve this problem. METHODS: The plasma pharmacokinetic of mangiferin calcium salt (MCS) and mangiferin were monitored by HPLC. The urine metabolomics of MCS were conducted by UPLC-Q-TOF-MS. RESULTS: The pharmacokinetic parameters of MCS have been varied, and the oral absorption effect of MCS was better than mangiferin. Also MCS had a good therapeutic effect on type 2 diabetes and NAFLD rats by regulating glucose and lipid metabolism. Sixteen potential biomarkers had been identified based on metabolomics which were related to the corresponding pathways including Pantothenate and CoA biosynthesis, fatty acid biosynthesis, citric acid cycle, arginine biosynthesis, tryptophan metabolism, etc. CONCLUSIONS: The present study validated the favorable pharmacokinetic profiles of MCS and the biochemical mechanisms of MCS in treating type 2 diabetes and NAFLD.

Pharmacokinetic comparison of five xanthones in rat plasma after oral administration of crude and processed Garcinia hanburyi extracts.

Gamboge, a dried resin secreted by Garcinia hanburyi Hook. f. (Guttiferae), possesses remarkable anticancer activity. However, due to toxicity, it must be processed before use in clinics. Xanthones are the main bioactive ingredients in gamboge. In order to elucidate the influence of processing technology on pharmacological properties of gamboge, an efficient, sensitive, and selective ultra-performance liquid chromatography coupled with triple quadruple mass spectrometry (UPLC-MS/MS) method of five critical xanthones, including ß-morellic acid (ß-MA), isogambogenic acid (IGNA), gambogenic acid (GNA), R-gambogic acid (GA), and S-GA in rat plasma was established for a comparative pharmacokinetics study of these xanthones after oral administration of crude and processed G. hanburyi extracts. The chromatographic separation of these five xanthones along with an internal standard (I.S.) was carried out on a Waters Acquity UPLC BEH C8 column with a gradient elution method using acetonitrile/0.1% formic acid-water as mobile phases. The eluate was detected by multiple-reaction monitoring (MRM) scanning with an electrospray ionization source operating in the positive ionization mode. Sample preparation involved a liquid-liquid extraction of the five analytes with ethyl acetate. Deoxyschizandrin was employed as an internal standard. This assay method was validated for selectivity, linearity, intra-day and inter-day precision, accuracy, recovery, matrix effect, and stability. The results revealed that the calibration curves displayed good linear regression (r > 0.995), and the lower limit of quantification (LLOQ) was <5.52 ng/mL for each analyte. The intra-day and inter-day precision (RSD) of the five xanthones at low, medium, and high levels was <10.58%, and the bias of the accuracy ranged from -8.54 to 10.2%. All other parameters fulfilled the FDA criteria for bioanalytical validation. In addition, the assay was successfully applied to the determination and pharmacokinetic study of these five xanthones after oral administration of crude and processed gamboge. Furthermore, Cmax of GNA and AUC0-t of IGNA were increased significantly (P < 0.05) after processing, while AUC0-t of ß-MA, R-GA, and S-GA decreased remarkably (P < 0.05), which suggested that processing exerted different effects on the absorption of xanthones. The results might be valuable for the clinical reasonable application and understanding the processing mechanism of gamboge.

Comparative Pharmacokinetic Study of Mangiferin in Normal and Alloxan-Induced Diabetic Rats after Oral and Intravenous Administration by UPLC-MS/MS.

BACKGROUNDS: Diabetes mellitus (DM)-induced morphological and/or functional complications may alter the pharmacokinetic profiles of mangiferin. This study aims to compare pharmacokinetic profiles of mangiferin in normal and alloxan-induced diabetic rats after oral and intravenous administration. METHODS: Mangiferin was administered orally (10 mg/kg) and intravenously (2 mg/kg) to normal and alloxan-induced diabetic Sprague-Dawley (SD) rats (n = 8). Blood samples were collected at different time points post-dose. Mangiferin and esculentoside (internal standard)  were analyzed by Waters Acquity ultra-performance liquid chromatography system and TSQ Quantum Ultra triple quadrupole mass spectrometer (UPLC-MS/MS). RESULTS: Mangiferin in normal and alloxan-induced diabetic rats experienced serious first-pass effect, which resulted in 1.71 and 0.80% of oral bioavailability respectively. Meanwhile, mangiferin was predominantly restricted to blood but not extensively distributed to organ tissues after intravenous administration. Compared with normal rats, the diabetic condition induced 53.26 and 50.90% decreases in Cmax and AUC0-t, respectively, for mangiferin after oral administration, and 63.08% decreases in Cmax after intravenous administration. CONCLUSIONS: Compared to normal rats, pharmacokinetic parameters of mangiferin were altered in diabetic condition induced by alloxan. The findings might help to provide useful evidence for modeling of diabetic rats and the clinical applications of mangiferin.

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.

Quantification of 1-(propan-2-ylamino)-4-propoxy-9H-thioxanthen-9-one (TX5), a newly synthetized P-glycoprotein inducer/activator, in biological samples: method development and validation.

A simple, rapid and economical method was developed and validated for the analysis and quantification of 1-(propan-2-ylamino)-4-propoxy-9H-thioxanthen-9-one (TX5), a P-glycoprotein inducer/activator, in biological samples, using reverse-phase high-performance liquid chromatography (HPLC). A C18 column and a mobile phase composed of methanol-water (90/10, v/v) with 1% (v/v) triethylamine, at a flow rate of 1 mL/min, were used for chromatographic separation. TX5 standards (0.5-150 µm) were prepared in human serum. Methanol was used for TX5 extraction and serum protein precipitation. After filtration, samples were injected into the HPLC apparatus and TX5 was quantified by a conventional UV detector at 255 nm. The TX5 retention time was 13 min in this isocratic system. The method was validated according to ICH guidelines for specificity/selectivity, linearity, accuracy, precision, limits of detection and quantification (LOD and LOQ) and recovery. The method was proved to be selective, as there were no interferences of endogenous compounds with the same retention time of TX5. Also, the developed method was linear (r2 ≥ 0.99) for TX5 concentrations between 0.5 and 150 µm and the LOD and LOQ were 0.08 and 0.23 µm, respectively. The results indicated that the reported method could meet the requirements for TX5 analysis in the trace amounts expected to be present in biological samples.

Development and validation of a liquid chromatography with tandem mass spectrometry method for the determination of isomangiferin in rat plasma with application to a preclinical pharmacokinetic study.

A sensitive and specific liquid chromatography with tandem mass spectrometry method was firstly developed for the measurement of isomangiferin in rat plasma. Chloramphenicol was selected as the internal standard. Sample preparation was carried out through a simple one-step protein precipitation procedure with methanol. Negative electrospray ionization was performed using multiple reaction monitoring mode with transitions of m/z 421.1/301.1 for isomangiferin, and 321.1/151.9 for chloramphenicol. The calibration curve was linear over the range of 0.1-600 ng/mL, with a lower limit of quantification at 0.1 ng/mL. The intra- and interday precisions (relative standard deviation) were no more than 8.2% and accuracies (relative error) were within the range of -8.4 to 2.2%. The recovery, matrix effect and stability under different conditions were all proved acceptable. The validated method has been successfully applied to a preclinical pharmacokinetic study of isomangiferin in rats for the first time.

Simultaneous determination of mangiferin and neomangiferin in rat plasma by UPLC-MS/MS and its application for pharmacokinetic study.

In this study, a sensitive and rapid ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed to determine mangiferin and neomangiferin in rat plasma simultaneously. Chromatographic separation was carried out on an Acquity UPLC BEH C18 column and mass spectrometric analysis was performed using a Xevo TQD triple quadruple mass spectrometer coupled with an electrospray ionization (ESI) source. The MRM transitions of m/z 423.2 → 303.1 and m/z 585.0 → 273.1 were used to quantify for mangiferin and neomangiferin, respectively. The linearity of this method was found to be within the concentration range of 5-2000 ng/mL for mangiferin, and 2-1000 ng/mL for neomangiferin in rat plasma, respectively. Only 3.0 min was needed for an analytical run. This assay was used to support a preclinical study to investigate the pharmacokinetics of mangiferin and neomangiferin in rats.

Enantiospecific pharmacokinetics of isoxanthohumol and its metabolite 8-prenylnaringenin in the rat.

SCOPE: Isoxanthohumol (IX) is a bioactive dietary prenylflavanone found in hops (Humulus lupulus L.), beer and nutraceuticals. IX is formed in vivo by xanthohumol and is a prodrug of 8-prenylnaringenin (8PN). IX and 8PN chirality has largely been ignored in the literature due to lack of enantiospecific bioanalytical methods. No single dose pharmacokinetic study of IX exists in the literature for any species. This study elucidates the enantiospecific pharmacokinetics of IX in rats and monitors the appearance of 8PN following intravenous and oral administration of ±IX. METHODS AND RESULTS: After intravenous (10 mg/kg) or oral (100 mg/kg) administration of ±IX to rats, serum, and urine were collected for 120 h and analyzed for IX and 8PN. Both were found as aglycones and glucuronide conjugates and displayed multiple peaking in serum suggestive of enterohepatic recycling. IX is primarily excreted through nonrenal routes. S-8PN was found excreted in the urine in greater amounts than R-8PN. Bioavailability was determined to be ∼4-5% for IX. CONCLUSION: Further enantiospecific pharmacokinetics of IX, subsequent 8PN and other metabolites are warranted along with continued enantiospecific bioactivity studies, especially in relation to gut microbial metabolism of IX and subsequent formation of 8PN.

Validation of an HPLC-MS-MS assay for determination of morellic acid in rat plasma: application to pharmacokinetic studies.

A selective and rapid high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS) was developed for the quantification of morellic acid in rat plasma. HPLC was performed using a Capcell MG C18 (50 × 4.6 mm, i.d., 5 µm) column, and isocratic elution with water-acetonitrile (20:80, v/v) at a flow rate of 0.5 mL/min. Sample preparation of analyte and internal standard (gambogic acid) involved liquid-liquid extraction using ethyl acetate-isopropanol (1:1, v/v) from 50 µL plasma. The precursor → production transitions for analyte and IS were m/z 559.4 → 471.3, and m/z 627.3 → 583.3, respectively, and were monitored on a triple-quadrupole mass spectrometer, operating in negative ion scan mode. The method was validated across the dynamic concentration range of 20-7,500 ng/mL for morellic acid, with a fast run time of 6.0 min. The analytical method measured concentrations of morellic acid with accuracy (% bias) of ≤6.4% and precision (% RSD) of ≤14.0%. Morellic acid was stable during the battery of stability studies. Finally, the applicability of this assay has been successfully demonstrated in vivo pharmacokinetic studies in Sprague-Dawley rats. This method will therefore be useful for further preclinical and clinical pharmacokinetic studies of morellic acid.

Metabolite profiling of Zi-Shen pill in rat biological specimens by UPLC-Q-TOF/MS.

This study aimed to profile the chemical constituents of Zi-Shen pill (ZSP) and its metabolites in plasma, urine, and prostate tissue, after administration into rats. Based on the chromatographic retention behavior, fragmentation patterns of chemical components, published literatures, and literature databases, an UPLC-Q-TOF/MS (LC-TOF/MS) method was established to identify the components of ZSP and its metabolites in biological samples. A total of 101 compounds were identified and tentatively characterized from the ZSP, including alkaloids, xanthones, and timosaponins. Except for 33 prototype components, 22 metabolites were detected in the plasma, urine, and prostate, and mainly came from Phellodendri Amurensis Cortex and Anemarrhenae Rhizoma. It was found that glucuronidation and sulfation were the major metabolic processes of xanthones, while oxidation, demethylation, and glucuronidation were the major metabolic pathways of alkaloids. In summary, the present study provided important chemical information on the metabolism of ZSP, indicating that alkaloids might be able to be absorbed into the prostate. The results provided a basis for further studies of the mechanisms of action for ZSP.

Simultaneous determination and pharmacokinetic study of gambogic acid and gambogenic acid in rat plasma after oral administration of Garcinia hanburyi extracts by LC-MS/MS.

Gambogic acid and gambogenic acid are two major bioactive components of Garcinia hanburyi, and play a pivotal role in biologic activity. In this study, a specific and sensitive liquid chromatography-tandem mass spectrometry was developed and validated for simultaneous determination of gambogic acid and gambogenic acid in rat plasma. Chromatographic separation was achieved on a C18 column using an isocratic elution with methanol-10 m m ammonium acetate buffer-acetic acid (90:10:0.1, v/v/v) as the mobile phase. The detection was performed on a triple-quadrupole tandem mass spectrometer equipped with electrospray positive ionization using multiple reaction monitoring modes. The transitions monitored were m/z 629.3 [M + H](+) → 573.2 for gambogic acid, m/z 631.2 [M + H](+) → 507.2 for gambogenic acid and m/z 444.2 [M + NH4 ](+) → 83.1 for IS. Linear calibration curves were obtained in the concentration range of 2.00-1000 ng/mL for gambogic acid and 0.500-250 ng/mL for gambogenic acid. The lower limits of quantification of gambogic acid and gambogenic acid in rat plasma were 2.00 and 0.500 ng/mL, respectively. The intra- and inter-day precision (RSD) values were <11.7% and accuracy (RE) was -10.6-12.4% at three QC levels for both analytes. The assay was successfully applied to evaluate pharmacokinetics behavior in rats after oral administration of Garcinia hanburyi extracts.

An improved LC-MS/MS method for the determination of mangiferin in rat plasma and its application in nonlinear pharmacokinetics.

A rapid and sensitive LC-MS/MS method was developed and validated for the determination of mangiferin in rat plasma. After simple protein precipitation of the plasma sample (100 microL) with 120 microL acetonitrile containing the internal standard rutin (500 ng/mL), the analytes were separated on a Zorbax SB-C18 column (150 x 2.1 mm, 3.5 microm) using an eluent of acetonitrile-0.05% formic acid in water (18:82, v/v), and then detected by electrospray ionization mass spectrometry in the negative multiple reaction monitoring mode with a chromatographic run time of 3.0 min. The method was sensitive, with a lower limit of quantification of 1 ng/mL and good linearity (r > 0.998) over the range of 1-250 ng/mL. It was also specific, precise and accurate when it was used to measure mangiferin levels in plasma and to characterize the pharmacokinetic properties following oral administration of mangiferin at a single dose of 5, 15, 45 and 90 mg/kg in rats. In addition, the pharmacokinetics of mangiferin were found to be nonlinear over the above dose range, which provides insight into dose regimen design of this potent compound in new drug development.

Determination of swertianolin in rat plasma by LC-MS/MS and its application to a pharmacokinetic study.

A sensitive and rapid LC-MS/MS method has been developed and validated for quantifying swertianolin in rat plasma using rutin as an internal standard (IS). Following liquid-liquid extraction with ethyl acetate, chromatographic separation for swertianolin was achieved on a C18 column with a gradient elution using 0.1% formic acid as mobile phase A and acetonitrile as mobile phase B at a flow rate of 0.3 mL/min. The detection was performed on a tandem mass spectrometer using multiple reaction monitoring via an electrospray ionization source and operating in the negative ionization mode. The optimized mass transition ion pairs (m/z) for quantitation were 435.1/272.0 for swertianolin and 609.2/300.1 for IS. The lower limit of quantitation was 0.5 ng/mL within a linear range of 0.5-500 ng/mL. Intra-day and inter-day precision was less than 6.8%. The accuracy was in the range of -13.9 to 12.0%. The mean recovery of swertianolin was >66.7%. The proposed method was successfully applied in evaluating the pharmacokinetics of swertianolin after an oral dose of 50 mg/kg Swertia mussotii extract in rats.

Simultaneous quantitation of polygalaxanthone III and four ginsenosides by ultra-fast liquid chromatography with tandem mass spectrometry in rat and beagle dog plasma after oral administration of Kai-Xin-San: application to a comparative pharmacokinetic study.

A fast, selective, and quantitative ultra-fast liquid chromatography with tandem mass spectrometry method has been developed and validated for the simultaneous quantitation of polygalaxanthone III, ginsenoside Rb1, ginsenoside Rd, ginsenoside Re, and ginsenoside Rg1 in the plasma of rat and beagle dog after oral administration of Kai-Xin-San. After addition of the internal standard, salidroside, the plasma samples were extracted by liquid-liquid extraction and separated on a Venusil MP C18 column with methanol/0.01% acetic acid water as mobile phase. The tandem mass spectrometric detection was performed in the multiple reaction monitoring with turbo ion spray source in a switching ionization mode. The method was examined, and found to be precise and accurate with the linearity range of the compounds. The intra- and interday precision and accuracy of the analytes were well within acceptance criteria (±15%). The mean extraction recoveries of analytes and internal standard were all >75.0%. The validated method has been successfully applied to comparing pharmacokinetic profiles of analytes in rat and beagle dog plasma. The results indicated that no significant differences were observed in pharmacokinetic parameters of ginsenoside Rg1, while the others had significant differences, which may due to the different mechanisms of absorption and metabolism.

Efficacy against subcutaneous or intracranial murine GL261 gliomas in relation to the concentration of the vascular-disrupting agent, 5,6-dimethylxanthenone-4-acetic acid (DMXAA), in the brain and plasma.

PURPOSE: Glioblastomas are amongst the most highly vascularised tumours, and the pursuit of anti-angiogenic approaches such as bevacizumab has provided short-term benefits. The purpose of this study was to determine whether the vascular-disrupting agent, dimethylxanthenone-4-acetic acid (DMXAA), could provide longer-lasting therapeutic benefits in a murine model of glioblastoma. METHODS: Luciferase-expressing murine GL261 glioma cells were inoculated subcutaneously or intracranially into C57Bl/6 mice. Mice with tumours were administered DMXAA, and tumours measured using callipers or by optical imager. Concentrations of DMXAA in plasma and brain were measured by LC-MS/MS. RESULTS: DMXAA (25 mg/kg) caused widespread necrosis at 24 h, a 9-day growth delay and complete regressions in 50 % of the mice with subcutaneous GL261 tumours. Co-administered lenalidomide (100 mg/kg) increased the growth delay to 20 days and the percentage of cures to 83 %. The same dose of DMXAA with or without lenalidomide had minimal effects on intracranial GL261 tumours. Concentrations of DMXAA extracted from brain tissue were approximately 25-fold lower than those measured in plasma 15 min to 4 h after DMXAA administration. The presence of intracranial GL261 tumours did not alter the concentrations of DMXAA entering the brain. CONCLUSIONS: DMXAA does not appear to cross the blood-brain barrier efficiently. Thus, whilst excellent activity was obtained against subcutaneous GL261 gliomas, minimal effects were observed against intracranial GL261 tumours. These results emphasise the need to use appropriate orthotopic models for the evaluation of new approaches for the treatment of brain cancers.

Antiplatelet, anticoagulant, and profibrinolytic activities of cudratricusxanthone A.

Cudratricusxanthone A (CTXA), a natural bioactive compound extracted from the roots of Cudrania tricuspidata Bureau, is known to possess hepatoprotective, antiproliferative and anti-inflammatory activities. However, antiplatelet, anticoagulant, and profibrinolytic properties have not been studied. The anticoagulant activities of CTXA were measured by monitoring activated partial thromboplastin-time (aPTT), prothrombin time (PT), and the activities of cell-based thrombin and activated factor X (FXa). The effects of CTXA on the expressions of plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) were also tested in tumor necrosis factor-α (TNF-α) activated human umbilical vein endothelial cells. Our data showed that CTXA inhibited thrombin-catalyzed fibrin polymerization and platelet aggregation, prolonged aPTT and PT significantly and inhibited the activities and production of thrombin and FXa. CTXA prolonged in vivo bleeding time and inhibited TNF-α induced PAI-1 production. Furthermore, PAI-1/t-PA ratio was significantly decreased by CTXA. Collectively, these results indicate that CTXA possesses antithrombotic activities and suggest that the current study could provide bases for the development of new anticoagulant agents.

A UFLC-MS/MS method with a switching ionization mode for simultaneous quantitation of polygalaxanthone III, four ginsenosides and tumulosic acid in rat plasma: application to a comparative pharmacokinetic study in normal and Alzheimer's disease rats.

A fast, sensitive and reliable ultra fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method has been developed and validated for simultaneous quantitation of polygalaxanthone III (POL), ginsenoside Rb1 (GRb1), ginsenoside Rd (GRd), ginsenoside Re (GRe), ginsenoside Rg1 (GRg1) and tumulosic acid (TUM) in rat plasma after oral administration of Kai-Xin-San, which plays an important role for the treatment of Alzheimer's disease (AD). The plasma samples were extracted by liquid-liquid extraction using ethyl acetate-isopropanol (1:1, v/v) with salidrdoside as internal standard (IS). Good chromatographic separation was achieved using gradient elution with the mobile phase consisting of methanol and 0.01% acetic acid in water. The tandem mass spectrometric detection was performed in multiple reaction monitoring mode on 4000Q UFLC-MS/MS system with turbo ion spray source in a negative and positive switching ionization mode. The lower limits of quantification were 0.2-1.5 ng/ml for all the analytes. Both intra-day and inter-day precision and accuracy of analytes were well within acceptance criteria (±15%). The mean absolute extraction recoveries of analytes and IS from rat plasma were all more than 60.0%. The validated method has been successfully applied to comparing pharmacokinetic profiles of analytes in normal and AD rat plasma. The results indicated that no significant differences in pharmacokinetic parameters of GRe, GRg1 and TUM were observed between the two groups, while the absorption of POL and GRd in AD group were significantly higher than those in normal group; moreover, the GRb1 absorbed more rapidly in model group. The different characters of pharmacokinetics might be caused by pharmacological effects of the analytes.

Single dose oral pharmacokinetic profile of α-mangostin in mice.

The mangosteen fruit (Garcinia mangostana) is a rich source of dietary xanthones with the most prominent being α-mangostin. Dietary xanthones have been reported to have a variety of health promoting properties. Until now, in vivo studies on the pharmacokinetic profile of α-mangostin are limited. For this study we employed an LC/MS/MS assay to determine the pharmacokinetic properties of α-mangostin suspension in cottonseed oil in C57BL/6 Mice. Mice were administered 100 mg/kg of α-mangostin by oral gavage and the plasma levels were analyzed over a 24 hour period. We observed the degree of exposure (i.e. area under the curve) of α-mangostin to be 5,736 nmol/L/hr and the maximum plasma concentration was 1,382 nmol/L. Furthermore, we provide evidence that α-mangostin undergoes glucuronidation into monoglucuronide and diglucuronide metabolites. Our study demonstrated that α-mangostin when administered in cotton seed oil to mice at a dose equivalent to 615 mg in a 90kg human adult achieves an approximate maximum plasma concentration of 1,300 nmol/L and is detectable for up to 24 hours. Further research is needed to understand the relationship between the pharmacokinetic properties of α-mangostin following oral administration and reported health benefits.