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Glutathione (GSH) is an important antioxidant that is generated and degraded via the GSH cycle. Quantification of the main components in the GSH cycle is necessary to evaluate the process of GSH. In this study, a robust ultra-performance liquid chromatography-tandem mass spectrometry method for the simultaneous quantification of 10 components (GSH; γ-glutamylcysteine; cysteinyl-glycine; n-acetylcysteine; homocysteine; cysteine; cystine; methionine; glutamate; pyroglutamic acid) in GSH cycle was developed. The approach was optimized in terms of derivative, chromatographic, and spectrometric conditions as well as sample preparation. The unstable thiol groups of GSH, γ-glutamylcysteine, cysteinyl-glycine, n-acetylcysteine, cysteine, and homocysteine were derivatized by n-ethylmaleimide. The derivatized and underivatized analytes were separated on an amino column with gradient elution. The method was further validated in terms of selectivity (no interference), linearity (R2 > 0.99), precision (% relative standard deviation [RSD%] range from 0.57 to 10.33), accuracy (% relative error [RE%] range from -3.42 to 10.92), stability (RSD% < 5.68, RE% range from -2.54 to 4.40), recovery (RSD% range from 1.87 to 7.87) and matrix effect (RSD% < 5.42). The validated method was applied to compare the components in the GSH cycle between normal and oxidative stress cells, which would be helpful in clarifying the effect of oxidative stress on the GSH cycle.
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Glutatión , Espectrometría de Masas en Tándem , Espectrometría de Masas en Tándem/métodos , Glutatión/análisis , Cromatografía Líquida de Alta Presión/métodos , Humanos , Homocisteína/análisis , Cisteína/análisis , Ácido Pirrolidona Carboxílico/análisis , Ácido Pirrolidona Carboxílico/química , Ácido Pirrolidona Carboxílico/metabolismo , Dipéptidos/análisis , Acetilcisteína/análisis , Acetilcisteína/química , Cistina/análisisRESUMEN
INTRODUCTION: Sulfur-fumigation of Paeoniae Radix Alba (PRA) could induce the chemical transformation of its bioactive component paeoniflorin into a sulfur-containing derivative paeoniflorin sulfite, and thus alter the quality, bioactivities, pharmacokinetics, and toxicities of PRA. However, how sulfur-fumigated PRA (S-PRA) affects the quality of PRA-containing complex preparations has not been intensively evaluated. OBJECTIVES: We intend to evaluate the influence of S-PRA on the overall quality of three kinds of Si-Wu-Tang (SWT) formulations, i.e., decoction (SWT-D), granule (SWT-G), and mixture (SWT-M). MATERIAL AND METHODS: An UPLC-DAD multi-components quantification method was used to compare the transfer rates of paeoniflorin sulfite and other 10 bioactive components between S-PRA-containing and NS-PRA-containing SWT formulations. An UPLC-QTOF-MS/MS-based target metabolomics approach was applied to explore the differential sulfur-containing derivatives in S-PRA-containing SWT formulations. RESULTS: The transfer rates of paeoniflorin sulfite in three S-PRA-containing SWT formulations were all higher than 100%. Moreover, S-PRA also increased the transfer rate of 5-hydroxymethylfurfural, 1,2,3,4,6-O-pentagalloylglucose, whereas decreased that of paeoniflorin, albiflorin, and ferulic acid in three SWT formulations. Six pinane monoterpene glucoside sulfites originally identified in S-PRA, were also detectable in three S-PRA-containing SWT formulations. In addition, seven phenolic acid sulfites including (3Z)-6-sulfite-ligustilide, (3E)-6-sulfite-ligustilide, 6,8-disulfite-ligustilide, ferulic acid sulfite, neochlorogenic acid sulfite, chlorogenic acid sulfite, and angelicide sulfite (or isomer) were newly identified in these three S-PRA-containing formulations. CONCLUSION: S-PRA could differentially affect the transfer rate of paeoniflorin sulfite and other bioactive components during the preparation of three SWT formulations and subsequently the overall quality thereof.
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Medicamentos Herbarios Chinos , Fumigación , Paeonia , Azufre , Espectrometría de Masas en Tándem , Paeonia/química , Medicamentos Herbarios Chinos/química , Cromatografía Líquida de Alta Presión/métodos , Espectrometría de Masas en Tándem/métodos , Azufre/química , Fumigación/métodos , Glucósidos/química , Monoterpenos/química , Metabolómica/métodosRESUMEN
INTRODUCTION: Zishui-Qinggan decoction (ZQD) is a classical traditional Chinese medicine formula (TCMF) for alleviating menopausal symptoms (MPS) induced by endocrine therapy in breast cancer patients. In the production of TCMF modern preparations, ethanol precipitation (EP) is a commonly but not fully verified refining process. OBJECTIVES: Chemical profiling/serum pharmacochemistry and network pharmacology approaches were integrated for exploring the rationality of the EP process in the production of ZQD modern preparations. MATERIAL AND METHODS: Ultra-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UPLC-QTOF-MS/MS) was applied to identify the chemical profiles and absorbed components of ZQD. Network pharmacology was used to identify targets and pathways related to MPS-relieving efficacy. RESULTS: The chemicals of ZQDs without/with EP process (referred to as ZQD-W and ZQD-W-P, respectively) were qualitatively similar with 89 and 87 components identified, respectively, but their relative contents were different; 51 components were detectable in the serum of rats orally administered with ZQD-W, whereas only 19 were detected in that administered with ZQD-W-P. Key targets, such as AKT1, and pathways, such as the PI3K-Akt signalling pathway, affected by ZQD-W and ZQD-W-P were similar, while the neuroactive ligand-receptor interaction pathway among others and the MAPK signalling pathway among others were specific pathways affected by ZQD-W and ZQD-W-P, respectively. The specifically absorbed components of ZQD-W could combine its specific key targets. CONCLUSION: The EP process quantitatively altered the chemical profiles of ZQD, subsequently affected the absorbed components of ZQD, and then affected the key targets and pathways of ZQD for relieving MPS. The EP process might result in variation of the MPS-relieving efficacy of ZQD, which deserves further in vivo verification.
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Medicamentos Herbarios Chinos , Etanol , Farmacología en Red , Espectrometría de Masas en Tándem , Medicamentos Herbarios Chinos/química , Espectrometría de Masas en Tándem/métodos , Cromatografía Líquida de Alta Presión/métodos , Animales , Etanol/química , Ratas Sprague-Dawley , Ratas , Precipitación Química , Medicina Tradicional ChinaRESUMEN
INTRODUCTION: Prunellae Spica (PS) is a commonly used medicinal herb in China. Secondary metabolites and saccharides are major bioactive components of PS. However, holistic quality consistency of commercial PS is ambiguous due to lack of comprehensive evaluation methods and reliable quality control markers. OBJECTIVES: Integrating multiple chromatographic and chemometric methods to comprehensively evaluate the holistic quality of PS. MATERIAL AND METHODS: Ultrahigh-performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (UPLC-TQ-MS/MS) was applied to quantify 12 secondary metabolites of PS. High-performance liquid chromatography coupled with photodiode array/evaporative light scattering detection (HPLC-PDA/ELSD) and high-performance gel permeation chromatography (HPGPC) methods were used to characterise the saccharides. Multivariate statistical analysis was adopted to evaluate the quality consistency of commercial PS and explore the potential quality control markers. RESULTS: The contents of secondary metabolites and saccharides were significantly different among commercial PS. All samples could be classified into three groups with ferulic acid, protocatechualdehyde, gallic acid, ursolic acid/oleanolic acid, sucrose, p-coumaric acid, chlorogenic acid as the major contributing components responsible for the difference. The content of rosmarinic acid was correlated with that of betulinic acid, hyperposide, chlorogenic acid, rutin, caffeic acid, p-coumaric acid and glucose, whereas polysaccharides, ferulic acid, protocatechualdehyde and ursolic acid/oleanolic acid, quercetin, sucrose and majority monosaccharides were not. CONCLUSION: The holistic quality of commercial PS was inconsistent. Together with rosmarinic acid, ferulic acid, protocatechualdehyde, ursolic acid/oleanolic acid, polysaccharides and sucrose might be recommended as potential quality control markers for the holistic quality control of PS.
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Ácido Oleanólico , Triterpenos , Espectrometría de Masas en Tándem/métodos , Triterpenos/análisis , Polisacáridos , Sacarosa , Cromatografía Líquida de Alta Presión/métodos , Ácido Rosmarínico , Ácido UrsólicoRESUMEN
INTRODUCTION: Apocyni Veneti Folium (AVF) is a commonly used traditional Chinese medicinal herb for the treatment of hypertension. Chemical markers are crucial for the quality control of herbal medicines; however, the therapeutic components of AVF remain to be well elucidated. OBJECTIVES: This study was intended to integrate serum pharmacochemistry and network pharmacology to identify chemical markers of AVF and establish an efficacy-related quality control method of AVF. MATERIAL AND METHODS: Ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UPLC-QTOF-MS/MS) was applied to identify the absorbed AVF constituents in rat serum. Network pharmacology was further used to identify anti-hypertension-related chemical markers. Subsequently, a quantitative method was established using UPLC with diode array detection (DAD) and applied for quality evaluation of commercial AVF samples. RESULTS: Thirteen prototype constituents were unequivocally or tentatively characterized in serum samples, among which quercetin, kaempferol, hyperoside, isoquercitrin, chlorogenic acid, cryptochlorogenic acid, and neochlorogenic acid were identified as dominant chemicals related to anti-hypertensive efficacy. The quantitative data showed that the total contents of seven marker components even showed 2-fold variation among 14 batches of commercial AVF samples with RSD values ranging from 12.15% to 75.61%. Hierarchical cluster analysis and heatmap analysis showed that 14 batches of commercial AVF samples could be divided into three main groups. CONCLUSION: The chemical markers obtained from this study could be applicable for efficacy-related quality control of AVF.
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Medicamentos Herbarios Chinos , Flavonoides , Ratas , Animales , Flavonoides/análisis , Espectrometría de Masas en Tándem , Farmacología en Red , Control de Calidad , Extractos Vegetales/farmacología , Extractos Vegetales/química , Cromatografía Líquida de Alta Presión/métodos , Medicamentos Herbarios Chinos/farmacología , Medicamentos Herbarios Chinos/químicaRESUMEN
This study aims to evaluate the quality consistency of Saposhnikoviae Radix based on carbohydrates, and explore the potential of carbohydrates as the internal quality control indicators of Saposhnikoviae Radix. The total polysaccharides were quantified by UV-Vis spectrophotometry and the molecular weight range of the polysaccharides was determined by high performance gel-permeation chromatography-evaporative light scattering detection(HPGPC-ELSD). The monosaccharides in polysaccharides and the free monosaccharides were quantified by high performance liquid chromatography-UV detection(HPLC-UV), and the oligosaccharides and fructose were quantified by high performance liquid chromatography-evaporative light scattering detection(HPLC-ELSD). The carbohydrate-based quality of Saposhnikoviae Radix was compared among 45 batches of commercial samples and 13 batches of self-collected samples. The results showed that the molecular weight distribution, monosaccharide composition, oligosaccharide, and free monosaccharide composition were similar in the 58 batches of samples. The average content of total polysaccharides, oligosaccharides, and total free monosaccharides in commercial samples were 39.66, 148.79, and 68.62 mg·g~(-1), respectively. The content showed significant differences among batches, with the highest differences of 3.51, 1.75, and 2.58 times, respectively. The RSD of the relative ratios of monosaccharides in the polysaccharides in commercial samples reached 28%-45%. The average content of total polysaccharides, oligosaccharides, and total free monosaccharides in self-collected samples were 68.07, 145.76, and 42.04 mg·g~(-1), respectively, with the inter-region differences of 2.88, 1.88, and 1.07 times, respectively. The RSD of the relative ratios of monosaccharides in polysaccharides in self-collected samples ranged from 8.2% to 59%. The total polysaccharides and total free monosaccharides in self-collected samples were 1.72 times higher and 1.63 times lower, respectively, than those in commercial samples. The content of oligosaccharides was similar between self-collected samples and commercial samples. To sum up, carbohydrates are one of the material bases for the internal quality consistency of Saposhnikoviae Radix. The qualitative characteristics of polysaccharides and the quantitative characteristics of polysaccharides and oligosaccharides are related to the origin of medicinal materials. Moreover, the quantitative characteristics of polysaccharides and free monosaccharides may be related to the storage conditions. Carbohydrates are potential indicators for the quality control of Saposhnikoviae Radix and deserve attention.
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Carbohidratos , Monosacáridos , Polisacáridos , Cromatografía Líquida de Alta Presión/métodos , OligosacáridosRESUMEN
Cicadae Periostracum (CP) is a traditional Chinese medicinal herb derived from the slough that is molted from the nymph of the insect Cryptotympana pustulata Fabricius. Washing with water to remove residual silt is a primary processing method of CP that is recommended by the Chinese Pharmacopoeia, but how washing methods affect the quality and bioactivity of CP is unknown. In this study, the quality and bioactivity of non-washed CP (CP-NW), post-molting-washed CP (CP-WAT), and pre-molting-washed CP (CP-WBT) were comparatively investigated. The quality of these CP samples was evaluated in terms of the UPLC-QTOF-MS/MS-based chemical profiling and semi-quantification of 39 N-acetyldopamine oligomers (belonging to six chemical types), the HPLC-UV-based quantification of 17 amino acids, the ICP-MS-based quantification of four heavy metals, and the contents of ash; the bioactivities of the samples were compared regarding their anti-oxidant and anti-inflammatory activities. It was found that, compared with CP-NW, both CP-WBT and CP-WAT had significantly lower contents of ash and heavy metals. Moreover, compared with CP-WAT, CP-WBT contained lower levels of total ash, acid-insoluble ash, and heavy metals and higher contents of N-acetyldopamine oligomers and amino acids. It also had enhanced anti-oxidant and anti-inflammatory activities. A Spearman's correlation analysis found that the contents of N-acetyldopamine oligomers and free amino acids were positively correlated with the anti-oxidant/-inflammatory activities of CP. All these results suggest that pre-molting washing can not only remove the residual silt but can also avoid the loss of the bioactive components and assure higher bioactivities. It is concluded that pre-molting washing could enhance the quality and bioactivity of CP and should be a superior alternative method for the primary processing of qualified CP.
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Antioxidantes , Metales Pesados , Antioxidantes/farmacología , Oxidantes , Espectrometría de Masas en Tándem , Muda , Antiinflamatorios/farmacología , Metales Pesados/análisis , AminoácidosRESUMEN
INTRODUCTION: Triterpene acids from the dried sclerotia of Poria cocos (Schw.) Wolf (poria) were recently found to possess anti-cancer activities. Identification of more triterpene acid analogues in poria is worthwhile for high throughput screening in anti-cancer drug discovery. OBJECTIVE: To establish an efficient dereplication strategy for identifying triterpene acid analogues in poria based on ultra-performance liquid chromatography with electrospray ionisation quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-QTOF-MS/MS). METHODOLOGY: The structural characteristics and mass spectrometric data profiles of known triterpene acids previously reported in poria were used to establish a predicted-analogue database. Then, the quasi-molecular ions of components in a poria extract were automatically compared with those in the predicted-analogue database to highlight compounds of potential interest. Tentative structural identification of the compounds of potential interest and discrimination of isomers were achieved by assessing ion fragmentation patterns and chromatographic behaviour prediction based on structure-retention relationship. RESULTS: A total of 62 triterpene acids were unequivocally or tentatively characterised from poria, among which 17 triterpene acids were tentatively identified for the first time in poria. CONCLUSION: This study provided more structure information of triterpene acids in poria for future high throughput screening of anti-cancer candidates. It is suggested that this semi-automated approach in which MS data are automatically compared to a predictive database may also be applicable for efficient screening of other herbal medicines for structural analogues of proven bioactives.
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Ácidos/química , Cromatografía Líquida de Alta Presión/métodos , Espectrometría de Masa por Ionización de Electrospray/métodos , Espectrometría de Masas en Tándem/métodos , Triterpenos/análisis , Wolfiporia/química , Minería de Datos , Estándares de Referencia , Relación Estructura-Actividad , Triterpenos/química , Triterpenos/normasRESUMEN
INTRODUCTION: The Chinese medicine formulation, tumour-shrinking decoction (TSD, FM1523), which consists of 15 natural medicines, is used for uterine fibroids (UFs) therapy and possesses excellent clinical therapeutic effect. OBJECTIVE: To develop a sensitive and validated analytical method for the simultaneous quantification of four crucial bioactive compounds including isorhamnetin-3-O-neohesperidoside, curcumin, peimine and tetrahydropalmatine in the principal formulation of this decoction. METHODS: An ultra-performance liquid chromatography coupled tandem mass spectrometry (UPLC-MS/MS) with an electrospray ionisation (ESI) source in multiple reaction monitoring (MRM) mode was conducted to investigate these bioactive compounds in the TSD. The chromatographic separation was performed on a C18 column when the flow rate was adjusted at 0.2 mL/min with gradient elution of acetonitrile-water with 0.1% formic acid. Accelerated solvent extraction (ASE) method with higher extraction efficiency was employed for TSD sample pre-treatment. RESULTS: The linearity, limit of detection (LOD) and limit of quantification (LOQ) were determined for this analytical method. The mean recoveries of the compounds were determined between 100.23% and 104.02% with satisfactory relative standard deviation (RSD) in the ranges of 2.65% to 3.81%. The precision was evaluated by intra-day and inter-day tests, which revealed RSD within the ranges of 1.21% to 2.14% and 1.24% to 2.32%, respectively. CONCLUSION: The bioactive compounds of TSD samples were successfully quantified via UPLC-MS/MS with MRM mode. This study could help to evaluate the pharmacokinetic study of TSD during clinical applications and present a facile strategy for quantifying bioactive compounds in traditional Chinese Medicine decoction.
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Alcaloides de Berberina/química , Cevanas/química , Medicamentos Herbarios Chinos/química , Leiomioma/tratamiento farmacológico , Fitoquímicos/química , Alcaloides de Berberina/aislamiento & purificación , Cevanas/aislamiento & purificación , Cromatografía Líquida de Alta Presión , Humanos , Límite de Detección , Fitoquímicos/aislamiento & purificación , Espectrometría de Masas en TándemRESUMEN
Herbal medicines (HMs) are much appreciated for their significant contribution to human survival and reproduction by remedial and prophylactic management of diseases. Defining the scientific basis of HMs will substantiate their value and promote their modernization. Ever-increasing evidence suggests that gut microbiota plays a crucial role in HM therapy by complicated interplay with HM components. This interplay includes such activities as: gut microbiota biotransforming HM chemicals into metabolites that harbor different bioavailability and bioactivity/toxicity from their precursors; HM chemicals improving the composition of gut microbiota, consequently ameliorating its dysfunction as well as associated pathological conditions; and gut microbiota mediating the interactions (synergistic and antagonistic) between the multiple chemicals in HMs. More advanced experimental designs are recommended for future study, such as overall chemical characterization of gut microbiota-metabolized HMs, direct microbial analysis of HM-targeted gut microbiota, and precise gut microbiota research model development. The outcomes of such research can further elucidate the interactions between HMs and gut microbiota, thereby opening a new window for defining the scientific basis of HMs and for guiding HM-based drug discovery.
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Microbioma Gastrointestinal , Plantas Medicinales/química , Salud , Humanos , Modelos BiológicosRESUMEN
Two-dimensional (2D) van der Waals semiconductors represent the thinnest, air stable semiconducting materials known. Their unique optical, electronic and mechanical properties hold great potential for harnessing them as key components in novel applications for electronics and optoelectronics. However, the charge transport behavior in 2D semiconductors is more susceptible to external surroundings (e.g. gaseous adsorbates from air and trapped charges in substrates) and their electronic performance is generally lower than corresponding bulk materials due to the fact that the surface and bulk coincide. In this article, we review recent progress on the charge transport properties and carrier mobility engineering of 2D transition metal chalcogenides, with a particular focus on the markedly high dependence of carrier mobility on thickness. We unveil the origin of this unique thickness dependence and elaborate the devised strategies to master it for carrier mobility optimization. Specifically, physical and chemical methods towards the optimization of the major factors influencing the extrinsic transport such as electrode/semiconductor contacts, interfacial Coulomb impurities and atomic defects are discussed. In particular, the use of ad hoc molecules makes it possible to engineer the interface with the dielectric and heal the vacancies in such materials. By casting fresh light on the theoretical and experimental studies, we provide a guide for improving the electronic performance of 2D semiconductors, with the ultimate goal of achieving technologically viable atomically thin (opto)electronics.
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We present the case of a patient who had experienced a fever of unknown cause for >7 months after surgical treatment for hallux valgus. A patch test revealed a positive reaction to a titanium alloy. All symptoms subsequently disappeared after we removed the implanted titanium screws. Histopathologic examination of the tissue surrounding the screws showed macrophage infiltration in the tissue. For >1 year after removal of the titanium screws, the patient's body temperature remained <37°C. These results support a diagnosis of titanium allergy in our patient. To the best of our knowledge, a long-term fever caused by an allergic reaction to mini-titanium screws of such a small size has not been reported. A review of 16 cases of titanium allergy reported in the published data confirmed that titanium allergy is extremely rare and that the clinical symptoms can vary. Titanium allergy should be suspected when a patient presents with a fever of unknown cause, delayed wound healing, dermatitis, or impaired fracture healing after internal fixation with titanium materials. A patch test for titanium or the lymphocyte transformation test could offer guidance for the clinical diagnosis of titanium allergy. Finally, we recommend that all patients should be asked whether they have a history of an allergy to any metal before surgery.
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Tornillos Óseos/efectos adversos , Fiebre/etiología , Hallux Valgus/cirugía , Hipersensibilidad/diagnóstico , Hipersensibilidad/etiología , Titanio/efectos adversos , Adolescente , Humanos , MasculinoRESUMEN
The amount of sulfur dioxide residue is currently employed by Chinese Pharmacopoeia (CP) as an index to screen sulfur-fumigated herbs, but it is unclear if this index can objectively reflect the quality of sulfur-fumigated herbs. In the present study, sulfur-containing derivatives were confirmed in sulfur-fumigated Moutan Cortex (MC) by UPLC-QTOF-MS/MS analysis, and the contents of sulfur-containing derivatives and sulfur dioxide residues were statistically analyzed both in self-made and commercially available sulfur-fumigated and non-fumigated MC as well as the samples thereof before and after eight-month storage. The amount of sulfur dioxide was significantly decreased, but that of the newly-generated sulfur-containing markers was not, after eight-month storage of the sulfur-fumigated MC samples, indicating that the amount of sulfur dioxide residue may not be positively correlated with the quality of sulfur-fumigated MC. Therefore, sulfur dioxide residue index alone may not objectively reflect the sulfur-fumigation extent (quality change extent) of MC, more specific method using characteristic sulfur-containing derivatives as chemical markers should be developed to supplement the sulfur dioxide residue determination in the quality control of sulfur-fumigated MC.
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Medicamentos Herbarios Chinos/química , Fumigación , Paeonia/química , Control de Calidad , Azufre/química , Cromatografía Líquida de Alta Presión , Dióxido de Azufre , Espectrometría de Masas en TándemRESUMEN
Dioscin (DIS), one of the most abundant bioactive steroidal saponins in Dioscorea sp., is used as a complementary medicine to treat coronary disease and angina pectoris in China. Although the pharmacological activities and pharmacokinetics of DIS have been well demonstrated, information regarding the final metabolic fates is very limited. This study investigated the in vivo metabolic profiles of DIS after oral administration by ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry method. The structures of the metabolites were identified and tentatively characterized by means of comparing the molecular mass, retention time and fragmentation pattern of the analytes with those of the parent compound. A total of eight metabolites, including seven phase I and one phase II metabolites, were detected and tentatively identified for the first time. Oxidation, deglycosylation and glucuronidation were found to be the major metabolic processes of the compound in rats. In addition, a possible metabolic pathway on the biotransformation of DIS in vivo was proposed. This study provides valuable and new information on the metabolism of DIS, which will be helpful for further understanding its mechanism of action.
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Cromatografía Líquida de Alta Presión/métodos , Dioscorea/química , Diosgenina/análogos & derivados , Medicamentos Herbarios Chinos/química , Medicamentos Herbarios Chinos/metabolismo , Espectrometría de Masas/métodos , Animales , Diosgenina/química , Diosgenina/metabolismo , Masculino , Estructura Molecular , Ratas , Ratas Sprague-DawleyRESUMEN
Qualitative and quantitative characterization of natural saccharides, especially polysaccharides, in herb materials remains a challenge due to their complicated structures and high macromolecular masses. Currently available methods involve time-consuming and complicated operations, and present poor specificity. Here, a novel and rapid high-performance gel permeation chromatography (HPGPC)-based approach is described for quality assessment of saccharide-dominant herbal materials by simultaneous qualitative and quantitative analysis of saccharide components. Dendrobium officinale, one of the rarest tonic herbs worldwide, was employed as the model herb in this study. First, a HPGPC fingerprint based on the molecular weight distribution of its carbohydrate components was established for qualitative identification of D. officinale. Then, HPGPC-guided dominant holistic polysaccharide marker was separated using ultra-filtration followed by HPGPC determination for quantitative evaluation of D. officinale. The experimental results suggest that this method is more efficient, stable, and convenient compared with the currently available methods for authentication and quality evaluation of D. officinale, and we expect the method will have similar advantages when used for quality control of other saccharide-dominant herbal materials and products.
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Carbohidratos/química , Cromatografía en Gel/métodos , Dendrobium/química , Extractos Vegetales/química , Plantas Medicinales/química , Control de CalidadRESUMEN
Two-dimensional semiconductors are structurally ideal channel materials for the ultimate atomic electronics after silicon era. A long-standing puzzle is the low carrier mobility (µ) in them as compared with corresponding bulk structures, which constitutes the main hurdle for realizing high-performance devices. To address this issue, we perform a combined experimental and theoretical study on atomically thin MoS2 field effect transistors with varying the number of MoS2 layers (NLs). Experimentally, an intimate µ-NL relation is observed with a 10-fold degradation in µ for extremely thinned monolayer channels. To accurately describe the carrier scattering process and shed light on the origin of the thinning-induced mobility degradation, a generalized Coulomb scattering model is developed with strictly considering device configurative conditions, that is, asymmetric dielectric environments and lopsided carrier distribution. We reveal that the carrier scattering from interfacial Coulomb impurities (e.g., chemical residues, gaseous adsorbates, and surface dangling bonds) is greatly intensified in extremely thinned channels, resulting from shortened interaction distance between impurities and carriers. Such a pronounced factor may surpass lattice phonons and serve as dominant scatterers. This understanding offers new insight into the thickness induced scattering intensity, highlights the critical role of surface quality in electrical transport, and would lead to rational performance improvement strategies for future atomic electronics.
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In the present study, an ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) method for simultaneous determination of eleven original, fourteen degraded ginsenosides and five aglycones was developed and validated to quantitatively evaluate the transformation of ginsenosides during preparation of Du-Shen-Tang, the decoction of ginseng. Both positive and negative modes as well as the step wave ion transfer optics technology were used to increase the detection sensitivity of QTOF-MS. The extracting ion mode based on the quasi-molecular ions, molecular ions and fragment ions characteristic to each analyte was used to increase the selectivity for quantitative analysis. Under the optimized UHPLC and QTOF-MS conditions, the 30 analytes with different polarities were separated (except for Re and Rg1) within 26 min. The developed method was applied for the quantitative comparison of Du-Shen-Tang and its raw materials derived from Asian ginseng (ASG) and American ginseng (AMG), respectively. It was found that the contents of the original ginsenosides decreased from 26,053.09 to 19,393.29 µg/g or 45,027.72 to 41,865.39 µg/g, whereas the degraded ginsenosides and aglycones increased from 159.72 to 685.37 µg/g or 676.54 to 1,502.26 µg/g in Du-Shen-Tang samples of ASG or AMG when compared with their raw materials, indicating that decocting could dramatically increase the proportion of the less polar degraded ginsenosides in Du-Shen-Tang. Whether these changed proportions of different polar ginsenosides could affect the bioactivities of the decoctions and their raw materials derived from ASG and AMG deserves further investigation.
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Ginsenósidos/aislamiento & purificación , Panax/química , Cromatografía Líquida de Alta Presión/métodos , Hidrólisis , Metanol , Extractos Vegetales/química , Sensibilidad y Especificidad , Solventes , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodosRESUMEN
The content of SO2 in Paeoniae Radix Alba (RPA) was determined by the method documented in Chinese Pharmacopoeia (CP) 2010 edition to validate the repeatability of the method for evaluating RPA, and the contents of paeoniflorin sulfonate in both the residual material and distilled solution of RPA were determined by HPLC to study the transformation of paeoniflorin sulfonate to SO2 by HCl. It was found that the repeatability of the method in CP for evaluating RPA is unacceptable, and paeoniflorin sulfonate was detectable in both the residual material and distilled solution of RPA even at "the end point" of SO2 determination, merely about 50% of paeoniflorin sulfonate was transformed to SO2 by HCl, indicating that the current SO2 determination method in CP is not able to accurately quantify SO2 in RPA. It is recommended that more special method for determining SO2 content in RPA should be developed regarding the chemical characteristics of sulfur-fumigated RPA.
Asunto(s)
Técnicas de Química Analítica/métodos , Medicamentos Herbarios Chinos/análisis , Paeonia/química , Farmacopeas como Asunto/normas , Dióxido de Azufre/química , Química Farmacéutica , Fumigación , Glucósidos/análisis , Monoterpenos/análisisRESUMEN
This article dealed with the effects of processing method and duration on the major bioactive components (sinigrin and sinapine thiocyanate) in Brassica juncea. The contents of sinigrin and sinapine thiocyanate in decoctions of raw and processed B. juncea were determined and compared by high performance liquid chromatography on a Alltima C18 column (4.6 mm x 250 mm, 5 microm) at 35 degrees C with the acetonitrile-0.1% phosphoric acid as the mobile phrase in gradient elution. The detection wavelength of sinigrin and sinapine thiocyanate was set at 227 nm and 326 nm, and the flow rate was 1.0 mL x min(-1). It was found that with the extended processing duration, the contents of sinigrin and sinapine thiocyanate first increased and then decreased: i.e., 0-2 minutes they increased gradually (for sinigrin, by 9.65% in processed products and 356. 10% in powder; for sinapine thiocyanate, by 12.82% in processed products and 3.41% in powder), and achieved their highest content at 2 min; then, decreased during the next 5 minutes (for sinigrin, by 80.35% in processed products and 82.09% in powder; for sinapine thiocyanate, by 14.29% in processed products and 17.54% in powder), suggesting that processing duration could significantly affect the contents of bioactive components in B. juncea, enzymatic hydrolysis of sinigrin when the seed is crushed in the present of moisture may be responsible for the content change. It is recommended that the slow fire should be the best processing method and the raw seed could be used directly in the water extracts related industrial production.
Asunto(s)
Brassica/química , Polvos/química , Colina/análogos & derivados , Colina/química , Medicamentos Herbarios Chinos/química , Glucosinolatos/química , Tiocianatos/químicaRESUMEN
An ultra-performance liquid chromatography-quadrupole/time of flight mass spectrometry (UPLC-Q-TOF-MS/MS) combined with reference herb method was developed to rapidly screen commercial sulfur-fumigated ginseng. Sufur-fumigated ginseng reference herb was prepared using genuine ginseng by conventional procedure. Then the reference sulfur-fumigated ginseng sample was analyzed by UPLC-Q-TOF-MS/MS to identify characteristic marker components. 25-hydroxyl-Re sulfate with higher abundance was se- lected as marker compound from 8 characteristic components identified in sulfur-fumigated ginseng reference herb. The fragmentation of 25-hydroxyl-Re sulfate was extensively investigated, fragment ion m/z 879.44 with higher intensity was chosen as the characteristic ion of sulfur-fumigated ginseng. The response of ion m/z 879. 44 was improved by optimizing the MS conditions so that this ion could be used as the characteristic marker ion for screening purpose in ion extracting screening mode. The established approach was successfully applied to inspect 21 commercial ginseng samples collected from different cities in China It was found that the chemical profiles of 9 samples were similar to that of sulfur-fumigated ginseng reference herb, and the characteristic ion m/z 879. 44 of 25-hydroxyl-Re sulfate was also detected in these samples, suggesting that there were nearly 43% ginseng samples analyzed being sulfur-fumigated. This findng agreed well with the results of sulfur dioxide residues of these 21 commercial ginseng samples determined with the method documented in Chinese Pharmacopeia Compared with the method documented in Chinese Pharmacopeia, the proposed approach is more rapid and specific for screening sulfur-fumigated ginseng. SFDA of China should strengthen the enforcement to prohibit ginseng being sulfur-fumigated, so that ginseng and it preparations could be effectively and safely benefit to the health of human beings.