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Hangzhou, China

Chen Z.-J.,Zhejiang University | Chen Z.-J.,Zhejiang Cancer Research Institute | Dai Y.-Q.,Zhejiang University | Kong S.-S.,Zhejiang University | And 7 more authors.
Molecular Nutrition and Food Research | Year: 2013

Scope: The study aimed to investigate the regioselectivity of methylation of luteolin (3′,4′,5,7-tetrahydroxyflavone) in human in vitro and in vivo. Methods and results: Recombinant human catechol-O-methyltransferase (COMT) and human liver S9 were utilized to study the kinetics of meta (3′)- and para (4′)- methylation of luteolin, and urine samples from volunteers after giving a luteolin-containing formulation were collected to determine the ratio of para-/meta-production. The results showed luteolin favored a para-methylation, with a ratio of of para-/meta-production in CLint (1.43 in recombinant human COMT and 1.47 in human liver S9), which was contrary to the known substrates of COMT. However, the result of urine sample assay showed a preference of meta-methylation with a ratio of of para-/meta-production (0.460 ± 0.126). To elucidate the mechanism for different preference of methylation of luteolin in vitro and in vivo, metabolism stability of the meta- and para-methylated luteolin was evaluated in human liver microsomes and recombinant human CYP450s, which revealed that para-methylated luteolin was more easily demethylated by human CYP1A2 and CYP3A4/5 than meta-methylated luteolin. Conclusion: Luteolin was a rare substrate of human COMT favoring a para-methylation, but further demethylation by human CYP1A2 and CYP3A4/5 caused a preference of accumulation in meta-methylated luteolin in vivo. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Zheng S.,Zhejiang Province Key Laboratory of Anti cancer Drug Research | Ma Z.,Zhejiang Province Key Laboratory of Anti cancer Drug Research | Song F.,Zhejiang Province Key Laboratory of Anti cancer Drug Research | Ye J.,Conba Pharmaceutical Co. | And 6 more authors.
Bioanalysis | Year: 2015

Background: Deficiency or imbalance of unsaturated fatty acids will promote the pathogenesis of many diseases. In order to monitor the exposure of unsaturated fatty acids, the method based on LC-MS/MS was developed. Results: Standard calibration curves for α-linolenic acid, linoleic acid, palmitoleic acid and oleic acid were linear (r ≥0.99). The intra-and interbatch accuracy (RE%) ranged from -4.5 to 8.6%, while the intra- and interbatch precisions (RSD%) were ≤8.7%. The extraction recovery varied from 85.4 to 99.6%, and no obvious matrix effect was observed. Conclusion: The method offers a simple approach for measuring 4 unsaturated fatty acids in 1 μl rat plasma within 3.95 min. © 2015 Future Science Ltd. Source


Zheng S.,Zhejiang University | Ma Z.,Zhejiang University | Han H.,Zhejiang University | Ye J.,Conba Pharmaceutical Co. | And 6 more authors.
Journal of Pharmaceutical and Biomedical Analysis | Year: 2014

Flavonoids are a group of important naturally occurring polyphenolic compounds with a wide range of biological effects. In this study, a sensitive liquid chromatography tandem mass spectrometry method was developed to simultaneously determine multiple active flavonoids, including quercetin (Que), kaempferol (Kae), apigenin (Api), isorhamnetin (Iso), luteolin (Lut), and naringenin (Nar), in rat plasma. To achieve a satisfied peak shape and LC separation, formic acid with the concentration between 0.05 and 0.2%, or in some case 5%, was generally used to acidify the LC mobile phase in reported studies. Here we found that even 0.05% formic acid could lead to strong mass signal suppression, and the absence of formic acid could reverse the signal suppression but cause serious peak tailing. There is an irreconcilable contradiction between liquid chromatography (LC) and mass spectrometry (MS). In order to simultaneously satisfy LC and MS, LC mobile phase with 0.00075% formic acid and post column mobile phase adjustment with 0.0677% ammonium solution in isopropanol were applied. Compared with the conventional method with mobile phase containing 0.05% formic acid, the mass signal response of Que, Kae, Api, Iso, Lut, Nar, and Oka increased 26.2, 18.6, 13.6, 23.5, 17.5, 15.6 and 15.4 fold, respectively. In addition, the post column mobile phase addition exhibited the better peak shape for the reduction of analytes longitudinal diffusion. The method has been fully validated according to FDA guidelines within the linear range between 0.328ngmL-1 and 168ngmL-1, and successfully applied to a pilot pharmacokinetic study of rats after administering 5.43gkg-1 Pollen of Brassica campestris. © 2014 Elsevier B.V. Source


Li L.,Zhejiang University | Gu L.,Zhejiang University | Chen Z.,Zhejiang University | Wang R.,Conba Pharmaceutical Co. | And 2 more authors.
Journal of Food Science | Year: 2010

Chrysanthemum morifolium extract (CME) has many pharmacological effects, and the effective components of CME are luteolin and apigenin which have been reported with cytotoxicity in vitro. The purpose of this study was to evaluate the safety of CME in Sprague-Dawley (S-D) rats. In the acute toxicity study, a single oral dose of 15 g/kg body weight (bw) CME was administered to rats, then the rats were observed for 14 d. No treatment-related death was observed, and the maximal tolerance dose estimated was greater than 15 g/kg bw in rats. In the long-term toxicity study, the rats were administered daily by gavage at dose levels of 320, 640, and 1280 mg/kg bw/d for consecutive 26 wk followed by 4 wk recovery period. The results showed that no toxicological changes in body weight, food, and water consumption, hematologic examination, blood biochemical examination, organ weight, and microscopic histopathologic examination were found in any treatment group. Therefore, CME is considered to be safe in general in rats at the limited dose level. © 2010 Institute of Food Technologists®. Source


Zheng S.,Zhejiang University | Ma Z.,Zhejiang University | Ye J.,Conba Pharmaceutical Co. | Wang G.,Zhejiang University | And 4 more authors.
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences | Year: 2014

24-Dehydropollinstanol (DEH), 24-methylene cholesterol (MET) and 31-norcycloartenol (NOR) are the functional triterpene alcohols of pollen of Brassica campestris. To study the pharmacokinetics of the above components of pollen of B. campestris in rats, a liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed. To avoid the interference of endogenous MET in rat plasma, fetal bovine serum (FBS) was selected as surrogate matrix and validated. Rat plasma was liquid-liquid extracted, then the chromatographic separation was conducted on a poroshell 120 SB C18 column (2.7μm, 2.1mm×50mm) at 38°C within 5.6min utilizing a gradient elution with a mobile phase consisting of (A) 0.1% formic acid in water and (B) 0.1% formic acid in methanol. The detection was performed on a triple quadrupole tandem mass spectrometer in multiple reaction monitoring (MRM) mode using positive atmospheric pressure chemical ionization (APCI). The method was validated over the concentration of 9.8-1560ng/ml; the inter-and-intra-day precisions (RSD %) were ≤7.8%, and the accuracies (RE %) were -5.3% to 12.2%, the extraction recovery ranged from 73.5% to 106.9% for all of these analytes, and no obvious matrix effect was observed. The developed method was applied successfully to study the pharmacokinetics of DEH, MET and NOR in rats after oral administration of pollen of B. campestris. © 2013 Elsevier B.V. Source

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