Chen Dai

China Pharmaceutical University, Nan-ching-hsü, Jiangxi Sheng, China

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Publications (14)48.66 Total impact

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    ABSTRACT: Neuroinflammatory disturbances have been closely associated with depression and many other neuropsychiatric diseases. Although targeting neuroinflammatory mediators with centrally-acting drugs has shown certain promise, its translation is faced with several challenges especially drug delivery and safety concerns. Here, we report that neuroinflammation-induced behavioral abnormality could be effectively attenuated with immunomodulatory agents that need not to gain brain penetration. In a rat model with intracerebral lipopolysaccharide (LPS) challenge, we validated that ginsenoside Rg1 (Rg1), a well-established anti-inflammatory agent, was unable to produce a direct action in the brain. Interestingly, peripherally-restricted Rg1 could effectively attenuate the weight loss, anorexic- and depressive-like behavior as well as neurochemical disturbances associated with central LPS challenge. Biochemical assay of neuroimmune mediators in the periphery revealed that Rg1 could mitigate the deregulation of the hypothalamic-pituitary-adrenal (HPA) axis and selectively blunt the increase in circulating interleukin (IL)-6 levels. Furthermore, these peripheral regulatory effects were accompanied by dampened microglial activation, mitigated expression of pro-inflammatory mediators and neurotoxic species in the central compartment. Taken together, our work suggested that targeting the peripheral immune system may serve as a novel therapeutic approach to neuroinflammation-induced neuropsychiatric disorders. Moreover, our findings provided the rationale for employing peripherally-active agents like Rg1 to combat mental disturbances.
    Neuroscience 10/2013; 256. DOI:10.1016/j.neuroscience.2013.10.023 · 3.33 Impact Factor
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    ABSTRACT: The main objective of the current study was to develop a universal method for a protein binding assay of complicated herbal components, and to investigate the possible relationship between compound polarity and protein binding using Schisadra lignans as an example. Firstly, the rat, dog and human plasma were spiked with three different concentrations of Schisandra chinensis extract (SLE), and ultramicrofiltration was used to obtain the unbound ingredients. Secondly, thirty-one Schisandra lignans in total plasma and ultrafiltered fluid were measured by LC-IT-TOFMS. Lastly, a relative exposure approach, which entailed calculating the relative concentrations of each Schisandra lignan from the corresponding calibration equation created from the calibration samples spiked with the stock solution of SLE, was applied in order to overcome the absence of authentic standards. The results showed that Schisandra lignans exhibited a high capability to bind with plasma protein, furthermore, the protein binding ratio of the lignan components increased proportionally with their individual chromatographic retention time, which indicated that the ratio of protein binding of lignans might increase accordingly with decreasing polarity. This study suggested that the compound polarity might be an important factor affecting the plasma protein binding of herbal components.
    07/2013; 11(4):442-448. DOI:10.1016/S1875-5364(13)60066-7
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    ABSTRACT: Yunnan Baiyao is a widely used herbal prescription in traditional medicine for the treatment of bleeding and hematological diseases, while its chemical profile remains elusive. In this work, a novel methodology combining polarity-directed extraction technique with a diagnostic ion filtering strategy based on LC hybrid ion trap TOF-MS analysis was developed for global, efficient, and rapid characterization of components in Yunnan Baiyao. Di-ethyl ether, n-butanol, and ethanol/water (70:30, v/v) covering low-to-high polarity ranges were chosen as the extraction solvent, respectively. The results clearly showed that, compared with conventional single extraction solvent, collaboratively using extraction solvents with different polarities can effectively increase the number of detected peaks and enrich the product ions information in multistage mass spectra analysis. By further matching diagnostic ions and fragmental pathways, a total of 34 components were successfully identified. Our work clearly demonstrates that integrating polarity-directed extraction and diagnostic ion filtering techniques is a powerful and reliable strategy for global detection and identification of complex chemicalome from herbal prescriptions, and may open new avenues for chemical analysis in other complex mixtures.
    Journal of Separation Science 06/2013; 36(12):1935-44. DOI:10.1002/jssc.201300244 · 2.59 Impact Factor
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    ABSTRACT: This study was to systematically investigate the effect of mobile phase additives, including ammonia water, formic acid, acetic acid, ammonium chloride and water (as a control), on qualitative and quantitative analysis of fifteen representative ginsenosides based on liquid chromatography hybrid quadrupole-time of flight mass spectrometry (LC-Q-TOF/MS). To evaluate the influence of mobile phase additives on qualitative performance, the quality of the negative mode MS/MS spectra of ginsenosides produced by online LC-Q-TOF/MS analyses, particularly the numbers and intensities of fragment ions, were compared under different adduct ion states, and found to be strongly affected by the mobile phase additives. When 0.02% acetic acid was added in the mobile phase, the deprotonated ginsenosides ions produced the most abundant product ions, while almost no product ion was observed for the chlorinated ginsenoside ions when 0.1mM ammonium chloride was used as the mobile phase additive. On the other hand, sensitivity, linear range and precision were adopted to investigate the quantitative performance affected by different mobile phase additives. Validation results of the LC-Q-TOF/MS-based quantitative performance for ginsenosides showed that ammonium chloride not only provided the highest sensitivity for all the target analytes, but also dramatically improved the linear ranges, the intra-day and inter-day precisions comparing to the results obtained using other mobile phase additives. Importantly, the validated method, using 0.1mM ammonium chloride as the mobile phase additive, was successfully applied to the quantitative analysis of ginsenosides in rat plasma after intragastric administration of Ginsenoside Extract at 200mg/kg. In conclusion, 0.02% acetic acid was deemed to be the most suitable mobile phase additive for qualitative analysis of ginsenosides, and 0.1mM ammonium chloride in mobile phase could lead to the best quantitative performance. Our results reveal that choosing the appropriate mobile phase additive is an important step in optimizing the analytical conditions, and the best quantitative method may not be suitable for the qualitative analysis.
    Journal of Chromatography A 04/2013; 1297. DOI:10.1016/j.chroma.2013.04.001 · 4.61 Impact Factor
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    ABSTRACT: The dopamine, serotonin, and kynurenine metabolic pathways play pivotal roles on brain function and their disturbances are closely related to various neurological diseases. Comprehensive measurement of these metabolites is thus essential for monitoring the global neurochemical responses to pathological challenges or drug intervention. However, simultaneous measurement of various neurochemcial metabolites represents a great challenge. We developed herein an original and feasible method using high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). A chemical derivatization approach using benzoyl chloride (benzoylation) was developed to achieve better chromatographic behavior and mass detecting sensitivity. The developed method enables a rapid quantification of 11 metabolites spanning dopamine, serotonin, and kynurenine metabolic pathways within 10.5 min. With this method, we were able to simultaneously monitor inflammation induced alternations of all these metabolites in rat brain and in particular their dynamics in plasma matrix. The balance between the serotonin and kynurenine branches of tryptophan metabolism was disrupted by lipopolysaccharide (LPS)-induced inflammation, characterized with the overproduction of neurotoxic metabolite 3-hydroxykynurenine and decreased levels of serotonine. The measured levels of this panel of neurotransimtters ranged from 4.3 ng to 10.6 μg per gram brain tissues. All these results support that the presently developed method is sufficiently sensitive and robust to simultaneously monitor a large panel of metabolites with diverse properties and large range of concentration differences. Therefore, this method will be expected highly useful for comprehensive studies of the pathophysiological roles and mechanisms of these critical neurotransmitters.
    Analytical Chemistry 10/2012; 84(22). DOI:10.1021/ac3025202 · 5.83 Impact Factor
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    ABSTRACT: This study describes the effectiveness of post-acquisition data processing techniques in detecting the lipid species rapidly from the massive data generated by high resolution mass spectrometry. The filtering approaches by product ions or neutral losses enabled glycerophospholipids and sterol conjugates to be identified based on the investigation of their fragmentation patterns, and the filtration by mass defect facilitated the detection of fatty acyl residues and bile acids by limiting the range of mass defect values. After application of these filtering techniques to mass spectra, the background noise was significantly filtered out and characteristic peaks of lipid species were efficiently sorted out. Totally 145 individual lipids were identified and structurally elucidated. Validation results of the LCMS-Q-TOF-based quantitative performance for all the peaks showed that the accuracy, expressed as relative errors (RE%), was lower than ±15%, and values (RSD%) of the inter-batch and intra-batch precision were lower than 15% in the assay. The developed method was integrated to the evaluation of plasma lipid profile from high fat diet versus energy restricted diet fed rats. A unique discrimination of the groups was successfully achieved through a principal component analysis (PCA).
    Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 08/2012; 905:43-53. DOI:10.1016/j.jchromb.2012.08.001 · 2.78 Impact Factor
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    ABSTRACT: This study was to develop and evaluate a practical approach of mass defect filtering (MDF), a post-acquisition data processing technique, for the rapid classification of complicated peaks into well-known chemical families based on the exact mass acquired by high resolution mass spectrometry. The full-scan LC-MS/MS data of the Ophiopogon japonicus extract was acquired using high performance liquid chromatography coupled with hybrid quadrupole-time of flight (LCMS-Q-TOF) system which features high resolution, mass accuracy, and sensitivity. To remove the interferences of the complex matrix, MDF approach was developed and employed to rapidly pick out the peaks of ophiopogonins and ophiopogonones from full-scan mass chromatograms. The accuracy of MDF was evaluated in reference to the result of structural identification. After the MDF based classification, both target and non-target components in Ophiopogon japonicus extract were characterized based on the detailed fragment ions analysis in the hybrid ion trap and time-of-flight mass spectrometry (LCMS-IT-TOF). By this approach, more than 50 ophiopogonins and 27 ophiopogonones were structurally characterized. The present results of rapid detection and identification of ophiopogonins and ophiopogonones suggest that the proposed MDF approach based on the high-resolution mass spectrometry data would be expected adaptable to the analysis of other herbal components.
    Journal of Chromatography A 03/2012; 1227:234-44. DOI:10.1016/j.chroma.2012.01.017 · 4.61 Impact Factor
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    ABSTRACT: The effectiveness of ginseng in preventing and treating various central nervous system (CNS) diseases has been widely confirmed. However, ginsenosides, the principal components of ginseng, are characterized by poor accessibility to the brain, and this pharmacokinetic-pharmacological paradox remains poorly explained. Anti-inflammatory approaches are becoming promising therapeutic strategies for depression and other CNS diseases; however, previous studies have focused largely on anti-inflammatory therapies directed at the central nervous system. It is thus of interest to determine whether ginsenosides, characterized by poor brain distribution, are also effective in treating lipopolysaccharide- (LPS) induced depression-like behavior and neuroinflammation. In an LPS-induced depression-like behavior model, the antidepressant effects of ginseng total saponins (GTS) were assessed using a forced swimming test, a tail suspension test, and a sucrose preference test. The anti-inflammatory efficacies of GTS in brain, plasma, and LPS-challenged RAW264.7 cells were validated using ELISA and quantitative real-time PCR. Moreover, indoleamine 2,3-dioxygenase (IDO) activity in the periphery and brain were also determined by measuring levels of kynurenine/tryptophan. GTS significantly attenuated LPS-induced depression-like behavior. Moreover, LPS-induced increases in 5-HT and tryptophane turnover in the brain were significantly reduced by GTS. IDO activities in brain and periphery were also suppressed after pretreatment with GTS. Furthermore, GTS-associated recovery from LPS-induced depression-like behavior was paralleled with reduced mRNA levels for IL-1β, IL-6, TNF-α, and IDO in hippocampus. Poor brain distribution of ginsenosides was confirmed in LPS-challenged mice. GTS treatment significantly decreased production of various proinflammatory cytokines in both LPS-challenged mice and RAW264.7 cells. This study suggests that the anti-depression efficacy of GTS may be largely attributable to its peripheral anti-inflammatory activity. Our study also strengthens an important notion that peripheral anti-inflammation strategies may be useful in the therapy of inflammation-related depression and possibly other CNS diseases.
    Journal of Neuroinflammation 08/2011; 8:100. DOI:10.1186/1742-2094-8-100 · 4.90 Impact Factor
    This article is viewable in ResearchGate's enriched format
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    ABSTRACT: We report herein, a facile metabolite identification workflow on the antimicrobial strictosamide, which is derived from accurate mass measurement by a hybrid ion trap-TOF mass spectrometer. In step 1, the parent drug and metabolites in rat bile were separated on an HPLC column followed by ion trap-TOF mass spectrometer analysis after a single oral dose of 50mg/kg strictosamide. In step 2, mass defect filter technique, which enables high-resolution mass spectrometers to be utilized for detecting drug metabolites based on well-defined mass defect ranges, was used to find metabolites in the mass spectrum. In step 3, the differences of accurate masses and their mass fragmentation pattern among the parent drug and metabolites used to assign structures for the metabolites successfully. As a result, five metabolites of strictosamide were found in rat bile, and all the metabolites were reported for the first time.
    Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 06/2011; 879(20):1819-22. DOI:10.1016/j.jchromb.2011.04.015 · 2.78 Impact Factor
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    ABSTRACT: A simple, sensitive and specific high-performance liquid chromatography mass spectrometry (LC-MS) method was developed and validated for the quantification of strictosamide in dog plasma. Strictosamide and internal standard (IS, ranolazine) extracted by liquid-liquid extraction with ethyl acetate were separated on a C(18) column using a gradient elution program. The detection was performed by selected ion monitoring mode via a positive electrospray ionization interface. The LLOQ was 1.0 ng/mL and the method exhibited acceptable precision, extraction efficiency and matrix effect. Finally, this proposed method was successfully applied to dog pharmacokinetic study and yielded the most comprehensive data on systemic exposure of strictosamide to date.
    Biomedical Chromatography 03/2011; 25(12):1338-42. DOI:10.1002/bmc.1606 · 1.95 Impact Factor
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    ABSTRACT: Metabolic research for herbal medicine (HM) is a formidable task, which is still in its infancy due to complicated components in HM, complex metabolic pathways, and lack of authentic standards. The present work contributes to the development of a powerful technical platform to rapidly identify and classify metabolites of herbal components based on a liquid chromatography hybrid ion trap time-of-flight mass spectrometry. Taking Schisandra lignans extract as an example, the metabolic studies were completed both in vitro and in vivo. In the in vitro study, metabolites for five representative Schisandra lignans were identified and structurally characterized. The major metabolic pathways were summed as demethylation, hydroxylation, and demethylation and hydroxylation. In the in vivo study, 44 metabolites were detected in rat urine. These metabolites were identified and classified rapidly according to the metabolic rules obtained in the in vitro studies, and hydroxylation was confirmed as the primacy metabolic pathway for lignans in rat urine. In addition, "relative cumulative excretion" (RCE) for the metabolites in female and male rats were calculated according to their relative intensities in the urine samples collected at 0 to 12, 12 to 24, and 24 to 36 h. As a result, great gender-related difference on RCE was observed. For most metabolites, RCE in female rats was significantly lower than that in male rats. In conclusion, the presently developed methodology and approach on metabolic research for Schisandra lignans will find its wide use in metabolic studies for herbal medicines.
    Drug metabolism and disposition: the biological fate of chemicals 10/2010; 38(10):1747-59. DOI:10.1124/dmd.110.033373 · 3.74 Impact Factor
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    ABSTRACT: Although pharmacokinetic alternations by hepatic injury have been extensively studied, little is known about the potential influence of hepatoprotective agent's treatment. This study was aimed to investigate the holistic pharmacokinetics of multiple lignans, CYP3A regulations, and their correlations with hepatic injury biomarkers, in hepatic injured rats pretreated with or without schisandra lignan extract (SLE) and dimethyl-diphenyl-bicarboxylate (DDB). Integral pharmacokinetics of multiple lignans based on an AUC-weighting approach was determined in normal, CCl4 induced hepatic injury rats pretreated with or without SLE and DDB. Protein expression and activities of CYP3A were determined. Pharmacokinetic parameters and CYP3A activities were correlated with serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels. CCl4 induced acute hepatic injury resulted in a nearly 8-fold enhancement of integral plasma exposures of multiple lignans, which was caused by the significant down-regulation of CYP3A. SLE and DDB pretreatment exhibited potent hepatoprotective effects, accompanied with the restored expression and activity of CYP3A, and the recovery of the respective and integral pharmacokinetics of lignans components. The integral AUC(0-tn) and CYP3A activities correlated well with ALT and AST. This study suggested that the pharmacokinetic regulating effects of hepatoprotective agent's on themselves and co-prescribed drugs should be of concern, and hepatic injury biomarkers may serve as good predictors.
    Journal of ethnopharmacology 09/2010; 131(2):290-9. DOI:10.1016/j.jep.2010.06.038 · 2.32 Impact Factor
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    ABSTRACT: To date, the pharmacokinetic research of herbal medicines (HMs) is still in its infancy and is facing critical technical challenges on the qualitative and quantitative analysis of complicated components from biological matrices. Additionally, the lack of authentic standards constitutes another bottleneck on assessing herbal pharmacokinetics. This present work contributes to the development of a powerful technical platform for both qualitative and quantitative pharmacokinetic analysis of herbal components, and a strategy of relative exposure that provides a practicable pharmacokinetic assessment independent of authentic standards, based on the use of liquid chromatography hybrid ion trap time-of-flight mass spectrometry (LC-IT-TOF/MS). Taking schisandra lignans extract (SLE) as an example, the LC-IT-TOF/MS assay was initially applied to the global qualitative analysis of components contained in SLE per se and in the rat plasma post SLE dosing. Afterwards, this study focused on validating the quantitative performance of LC-IT-TOF/MS assay by comparison with a well-established LC-Q/MS assay. For the absolute quantification of five lignans components with authentic standards, both assays showed very similar analytical figures of merit such as linearity, precision, accuracy, and pharmacokinetic parameters. Compared with LC-Q/MS, the prominent advantage of LC-IT-TOF/MS assay is its much higher sensitivity. Moreover, a 'relative exposure approach' (REA) that entails the use of sequentially diluted original herbal preparations to prepare the 'mixed calibration curves' was developed to assessing herbal pharmacokinetics independent of specific authentic compounds for each component. Such an approach was found capable of providing virtually identical pharmacokinetic parameters as that from the typical pharmacokinetic assay calibrated by authentic standards, except for the absolute plasma concentrations. The presently developed methodology and approach will find its wide use in, but not limited to, the qualitative and quantitative pharmacokinetic analysis of herbal medicines.
    Journal of Chromatography A 07/2010; 1217(30):4971-9. DOI:10.1016/j.chroma.2010.05.056 · 4.61 Impact Factor
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    ABSTRACT: Quadrupole (Q) mass spectrometers are the most popular analytical tools due to their reliability, effectiveness, and low cost. However, they are not suitable for quantitative analysis of multi-component since the sensitivity will get worse rapidly with the increasing number of m/z detected. The present work, for the first time, attempted to analyze of 16 saponins simultaneously using an approach of segmental and selected ion monitoring (SSIM) based on LC-Q/MS, and systematically investigated the influence of different SSIM modes on signal level/noise level (S/N), lower limits of quantification (LLOQ), upper limits of quantification (ULOQs), etc. Our results showed that a proper SSIM mode could not only provide much higher sensitivity for all the targeting analytes, but also dramatically broadened their dynamic ranges. The developed methodology could effectively break the application bottleneck on the quantitative analysis of multi-component with LC-Q/MS, and would be applied widely in related fields for multi-component analysis, such as environmental monitoring, metabonomics, Chinese herbal medicine research.
    Journal of Chromatography A 06/2010; 1217(26):4501-6. DOI:10.1016/j.chroma.2010.04.054 · 4.61 Impact Factor