查看更多>>摘要：A number of analytical studies, started in the sixties of the last century, concerning the stem bark of Geissospermum vellosii, have documented the presence of a number of indole alkaloids whose molecular identity was defined by NMR technique. The potential bioactivity of these compounds has inspired more recent analogous studies either devoted to structural elucidation of new alkaloid molecules or to the investigation of the role of some of them in cancer therapy. Anyway, a complete fingerprinting of the bark content is still lacking. In this paper, after a suitable extraction step, we obtain a chromatographic separation showing a number of components higher than the number of alkaloids so far described. Considering the great number of substances present in the stem bark, their identification is practically impossible to reveal by NMR techniques. As we presume that there are other stem bark unidentified alkaloids with important bioactivity, we propose to characterize their molecular structures by UV-Vis Diode Array spectrophotometry and High-Resolution Multistage Mass Spectrometry. The two adopted detection techniques were first tested on the already known Geissospermum vellosii molecules, and, after an inspection of their efficacy, were applied to the substances that have not yet been described. Herewith we propose the molecular structures of 10 substances that were never previously described, and in addition we provide experimental evidence of the presence of 6 already known substances which were never reported in the Geissospermum genus. A far more detailed description of the bark constituents is therefore provided.
查看更多>>摘要：Graphene oxide (GO) was introduced into a monolithic column and a network porous poly (GO-co-TAIC-co-MMA) monolith was prepared by redox polymerization. The internal morphology and pore size distribution of the polymer were observed by scanning electron microscopy, and the nitrogen adsorption-desorption and mercury intrusion methods. After optimization, 8 kinds of aromatic compounds were effectively separated in 5 min, and the theoretical plates number of the monolithic column exceeded 33, 070 plates m(-1). Five kinds of main ingredients were separated from the traditional Chinese medicine (Schisandra) ingredients and 26 peaks were successfully separated from the fermentation broth containing natural lipopeptide antibiotics. The addition of GO material enhanced the interaction between the compound and the monolithic column, increased the binding sites, improved the uniformity of the internal pore structure of the monolithic column, and improved the separation performance of the monolith. Methodologic validation of five ingredients in Schisandra showed that the correlation coefficients of the linear regressions were in the range of 0.9987-0.9997. The intra-and inter-day values of the relative standard deviation for precision were in the range of 0.6-4.1% and 1.1-4.8%, respec-tively. The values of accuracy (expressed as recovery) were in the range of 97.7-103.2%, 100.5-105.0%, 98.2-101.8%, 101.3-104.1%, and 101.2-103.3% for the 5 ingredients in order. In terms of the relative standard deviation of the retention time, the reproducibility of the monolithic column M1 was < 3.7%. The monolithic column based on GO has great potential in chromatographic separation.
查看更多>>摘要：Zingiber officinale and Panax ginseng, as well-known traditional Chinese medicines, have been used together to clinically treat ulcerative colitis with synergistic effects for thousands of years. However, their compatibility mechanism remains unclear. In this study, the shift of gut microbiome and fecal metabolic profiles were monitored by 16S rRNA sequencing technology and ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry analysis, respectively, which aimed to reveal the synergistic mechanism of Zingiber officinale and Panax ginseng on the amelioration of ulcerative colitis. The results showed that the relative abundance of beneficial bacteria (such as Muribaculaceae_norank, Lachnospiraceae NK4A136 group and Akkermansia) was significantly increased and the abundance of pathogenic bacteria (such as Bacteroides, Parabacteroides and Desulfovibrio) was markedly decreased after the intervention of Zingiber officinale-Panax ginseng herb pair. And a total of 16 differential metabolites related to ulcerative colitis were identified by the metabolomics analysis, which were majorly associated with the metabolic pathways, including arachidonic acid metabolism, tryptophan metabolism, and steroid biosynthesis. Based on these findings, it was suggested that the regulation of the gut microbiota-metabolite axis might be a potential target for the synergistic mechanism of Zingiber officinale-Panax ginseng herb pair in the treatment of ulcerative colitis. Furthermore, the integrated analysis of microbiome and metabolomics used in this study could also serve as a useful template for exploring the mechanism of other drugs.
查看更多>>摘要：Carcinoid tumors referred to neuroendocrine neoplasms that often are indolent and may not became clinical apparent until there has been metastatic spread. Urinary 5-hydroxyindoleacetic acid (5-HIAA) was recommended as a first-line screening biomarker for the diagnosis and follow-up of carcinoid tumors. The measurement of this analyte is conventionally performed by spectrophotometer or high performance liquid chromatography, and has switched to liquid chromatography-tandem mass spectrometry (LC-MS/MS) recently. In this study, a fast, simple and reliable LC-MS/MS method has been developed and validated for 24 h urinary 5-HIAA determination and the quality assurance referring to post-implementation monitoring has been explored. 50 mu L of urine was mixed with 200 mu L of a 50% methanol/water solution containing the internal standard 5-HIAA-d5. The mixture was centrifuged and the supernatant was used for direct analysis by LC-MS/MS. The retention time of 5-HIAA is 2.37 min and a total run time is 4 min. This method was validated for excellent linearity from 0.675 to 43.3 mu M with CVs <= 6.64% and good recovery in the range of 87.1%-107%. No obvious matrix effect was observed. Intra- and inter-day imprecision were below 3.95% and 4.66% respectively. The reference interval of 24-hour urinary 5HIAA in Chinese adults was established. The quality assurance could ensure reliable and comparable results in routine clinical testing. Thus, this fast, simple and reliable LC-MS/MS method could be proposed as a tool for clinical testing of urinary 5-HIAA in quality-controlled environments.
查看更多>>摘要：The fractionation of positional isomers of a PEGylated protein is quite challenging as these have similar mo-lecular weight, and only very slightly different surface charge. In this study, cation exchange z2 laterally-fed membrane chromatography (z2LFMC), which has been shown to be suitable for high-speed, high-resolution protein purification, was used to fractionate positional isomers of mono-PEGylated lysozyme. The performance of the z2LFMC device was compared with a commercial preparative cation exchange column having the same volume and ligand. PEGylated lysozyme purification experiments showed that while the positional isomers of mono-PEGylated lysozyme could not be satisfactorily resolved using the preparative commercial cation exchange column, almost baseline resolution of these could be achieved using the z2LFMC device. Moreover, the z2LFMC device-based process was faster by an order of magnitude. The results discussed in this paper demonstrate that z2LFMC is a superior alternative to column-based chromatography for challenging protein separations, such as the one discussed here, both in terms of speed and resolution.
查看更多>>摘要：In the study, purification of ovalbumin was performed by modifying polyamide hollow fiber membranes using immobilized metal affinity chromatography technique. For this purpose, firstly polyethyleneimine (PEI) solutions of different concentrations were attached to hollow fiber membranes. Then, Cu(II), Ni(II) and Zn(II) metal ions were chelated separately to polyethyleneimine attached hollow fiber membranes. Characterization studies of modified hollow fiber membranes were performed with scanning electron microscopy (SEM). Also, the surface area was measured with the Brunner Emmet Teller (BET) method and the porosity was measured with mercury porosimeter. pH, ionic strength, initial ovalbumin concentration, temperature and reusability parameters affecting adsorption capacity were investigated. The maximum ovalbumin adsorption capacities of hollow fiber membranes were found to be 317 mg/g for Cu(II), 169 mg/g for Ni(II) and 101 mg/g for Zn(II), respectively. Desorption ratio of metal ions were calculated as 91.6% for Cu(II), 92.9% for Ni(II) and 91.8% for Zn(II), which are quite high and suitable. When examined in terms of adsorption isotherm models, it was concluded that the Langmuir model is suitable. Purification of ovalbumin from egg white was carried out by fast performance liquid chromatography (FPLC), and the purity of ovalbumin was evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) method.
查看更多>>摘要：This work proposes a new method for biomonitoring studies focused on the screening and quantification of xenobiotics in blood-derived samples. The performance of a polydimethylsiloxane/divinylbenzene/polydimethylsiloxane (PDMS/DVB/PDMS) biocompatible extraction phase was investigated for extraction of pesticides and pharmaceuticals from plasma samples via direct immersion solid-phase microextraction (SPME) prior to gas chromatography-mass spectrometry. Under the optimum extraction settings, which included an attentive optimization of the fiber rinsing conditions, the microextraction device was able to endure 100 consecutive extractions from undiluted and diluted plasma with an overall reproducibility up to 28% for all the analytes tested, except chlorpyrifos-methyl. Optimized conditions were used to validate a quantitative method using matrix-matched calibration with isotopically labeled internal standard correction. Accuracy and precision values obtained for analysis of bovine plasma were within 96-132% and 0.05-5.82% respectively. LLOQs for all the analytes were at 1 mu g L-1 and LDR ranged within 1-100 mu g L-1. The applicability of this method to plasma from different species (human, rat, rabbit) was also investigated. This work represents the first step toward broader use of the biocompatible PDMS/DVB/PDMS extraction phases for analysis of multiclass xenobiotics in plasma and other complex biofluids.
查看更多>>摘要：Organoid is a burgeoning model that have emerged in the past decade. Tumor organoids can simulate specific aspects of the 3D structure, cell type composition and function of real tumors to make up for the deficiencies of cell models and animal models. Curcumin has been found to be effective in suppressing various phases of colorectal cancer development. Nevertheless, there is no clear evidence that the results obtained on cultured cells or animal models can be translated in humans. Therefore, we constructed patient-derived organoids of colorectal cancer to show the curcumin responses of these organoids. Then, a MS-based non-targeted metabolomic strategy was to gain a system-level understanding of the mechanism of curcumin on colorectal cancer patient-derived organoids. Then non-targeted metabonomic analysis found that curcumin mainly regulated the phenylalanine, tyrosine and tryptophan biosynthesis, nicotinate and nicotinamide metabolism, purine metabolism in the organoids of colorectal cancer. Our research provided a reference for further revealing the role of curcumin in human-derived colorectal cancer-like solid tumors.
查看更多>>摘要：Roxadustat (FG-4592) can inhibit the hypoxia-inducible factor prolyl hydroxylase (HIF-PH) enzymes that are responsible for targeting and regulating HIF for ubiquitination and proteasomal degradation. It has been approved in China as an anti-anemia drug for treating the anemia in dialysis-dependent CKD (chronic kidney disease) patients, and is also under regulatory review in Japan. Some studies are also investigating the clinical pharmacokinetics and pharmacodynamics of roxadustat in CKD patients. To support clinical investigations, a rapid high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method, with a concentration range from 1 to 5000 ng/mL, was designed for the quantification of roxadustat in human plasma and urine. Liquid-liquid extraction (LLE) was applied to sample clean-up followed by a chromatographic separation conducted on a Waters XTerra Phenyl column with isocratic elution. The mixture consisting of acetonitrile/water/formic acid (60:40:0.1[%], v/v/v) was employed as the mobile phase (flow rate: 1.0 mL/min) with 60% post-column split. The quantitation was employed in multiple reactions monitoring (MRM) mode based on positive electrospray ionization (ESI). This proposed method was fully validated and applied to the pharmacokinetic (PK) and pharmacodynamic (PD) study of roxadustat among healthy subjects in China.
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Elsevier