Hongmei Wen

Silver nanoparticles-enhanced time-resolved fluorescence sensor for VEGF(165) based on Mn-doped ZnS quantum dots.

A silver nanoparticles (AgNPs)-enhanced time-resolved fluorescence (TR-FL) sensor based on long-lived fluorescent Mn-doped ZnS quantum dots (QDs) is developed for the sensitive detection of vascular endothelial growth factor-165 (VEGF165), a predominant cancer biomarker in cancer angiogenesis. The aptamers bond with the Mn-doped ZnS QDs and the BHQ-2 quencher-labelling strands hybridized in duplex are coupled with streptavidin (SA)-functionalized AgNPs to form the AgNPs-enhanced TR-FL sensor, showing lower fluorescence intensity in the duplex state due to the fluorescence resonance energy transfer (FRET) between the Mn-doped ZnS QDs and quenchers. Upon the addition of VEGF165, the BHQ-2 quencher-labelling strands of the duplex are displaced, leading to the disruption of the FRET. As a result, the fluorescence of the Mn-doped QDs within the proximity of the AgNPs is recovered. The FL signal can be measured free of the interference of short-lived background by setting appropriate delay time and gate time, which offers a signal with high signal-to-noise ratio in photoluminescent biodetection. Compared with the bare TR-FL sensor, the AgNPs-based TR-FL sensor showed a huge improvement in fluorescence based on metal-enhanced fluorescence (MEF) effect, and the sensitivity increased 11-fold with the detection limit of 0.08 nM. In addition, the sensor provided a wide range of linear detection from 0.1 nM to 16 nM.

Identification of liguzinediol metabolites in rats by ultra performance liquid chromatography/quadrupole-time-of-flight mass spectrometry

Ultra performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UPLC/QTOF MS) was employed to investigate the in vivo metabolism of liguzinediol. Urine, bile, feces and plasma samples were collected after intravenous administration of 10mg/kg liguzinediol to healthy rats. Altogether seven metabolites were detected and tentatively identified based on the characteristics of their protonated ions. The metabolites were mainly transformed by four main metabolic pathways including oxidation, sulfation, glycine conjugation and glucuronidation.

Screening of immunomodulatory components in Yu-ping-feng-san using splenocyte binding and HPLC.

Yu-ping-feng-san (YPFS) is a widely used immunomodulatory herbal medication used in traditional Chinese medicine, but the active molecules remain obscure. To screen for bioactive components we combined splenocyte binding with high performance liquid chromatography (SB-HPLC). After enrichment by splenocyte binding, two YPFS components (C1 and C2) were analyzed by HPLC. Compound C2 was identified as linoleic acid (LA) based on UV absorption and mass spectrometry. Silica gel chromatography was used to purify compound C1 from Radix Saposhnikoviae, a major constituent of YPFS. This allowed identification of the molecule as panaxynol (PAN) based on EI-MS and NMR spectrometry. Bioassay in vitro demonstrated that PAN significantly inhibited splenocyte proliferation induced by concanavalin A (ConA) in a concentration-dependent manner, whereas LA had no significant effect on splenocyte proliferation. In vivo, PAN was found to attenuate allergic contact dermatitis in a mouse model of delayed-type hypersensitivity (DTH), a pharmacological activity not previously reported for this molecule. It is suggested that PAN contributes to the anti-DTH effects of YPFS. SB-HPLC provides a rapid and efficient method for the identification of potential immunomodulatory components in traditional Chinese medicines.

Development of polyacrylic acid-functionalized porous zinc sulfide nanospheres for a non-aqueous solid phase extraction procedure toward alkaloids

A polymer-based cation exchanger and silica-based sorbents are generally used for the conventional solid phase extraction (SPE) toward alkaloids, because they provide both ion exchange interactions and strong hydrophobic interactions between the stationary phase and samples. However, strong hydrophobic interactions could cause the retention of some non-alkaloid compounds, to reduce the selectivity for alkaloids. In this paper, a non-aqueous solid phase extraction (SPE) procedure was developed and optimized utilizing novel polyacrylic acid-functionalized porous zinc sulfide nanospheres (PAA–PZNs) as the sorbents for the enrichment of alkaloids. The SPE sorbents were fabricated by the amidation reaction of the poly-(acrylic acid) homopolymer with amino group modified PZNs, which afforded an abundance of carboxyl groups, to effectively eliminate non-alkaloid compounds and concentrate alkaloids from the extracts. They exhibited not only high extraction efficiency, high selectivity and high recoveries for alkaloids, but also good chemical and mechanical stability. Therefore, the PAA functionalized porous zinc sulfide nanospheres and subsequently prepared non-aqueous solid phase extraction (SPE) procedure may prove to be a strong tool for selective enrichment of alkaloids from extracts.

Synthesis and Biological Evaluation of Liguzinediol Mono- and Dual Ester Prodrugs as Promising Inotropic Agents

The potent positive inotropic effect, together with the relatively low safety risk of liguzinediol (LZDO), relative to currently available inotropic drugs, has prompted us to intensively research and develop LZDO as a potent positive inotropic agent. In this study, to obtain LZDO alternatives for oral chronic administration, a series of long-chain fatty carboxylic mono- and dual-esters of LZDO were synthesized, and preliminarily evaluated for physicochemical properties and bioconversion. Enhanced lipophilic properties and decreased solubility of the prodrugs were observed as the side chain length increased. All esters showed conspicuous chemical stability in phosphate buffer (pH 7.4). Moreover, the enzymatic hydrolysis of esters in human plasma and human liver microsomes confirmed that the majority of esters were converted to LZDO, with release profiles that varied due to the size and structure of the side chain. In vivo pharmacokinetic studies following oral administration of monopivaloyl (M5), monodecyl (M10) and monododecyl (M12) esters demonstrated the evidently extended half-lives relative to LZDO dosed alone. In particular the monopivaloyl ester M5 exhibited an optimal pharmacokinetic profile with appropriate physiochemical characteristics.

Metabolite identification of liguzinediol in dogs by ultra-flow liquid chromatography/tandem mass spectrometry

Ultra-flow liquid chromatography/quadrupole-time-of-flight mass spectrometry (UFLC/Q-TOF MS) method combined with metabolitepilot(MT) software was used for analysis of the metabolites of liguzinediol in dogs. Urine, bile, feces and plasma samples were collected after intravenous administration of 8 mg/kg liguzinediol to healthy dogs. Besides liguzinediol, seven metabolites were detected and identified by UFLC/Q-TOF MS method. The results showed that liguzinediol had some main metabolic pathways in dogs including oxidation, sulfation, cysteine conjugation, N-acetylcysteine conjugation and glucuronidation.

DETERMINATION OF FLAVONES IN LOPHATHERUM GRACILE BY LIQUID CHROMATOGRAPHY TANDEM MASS SPECTROMETRY

Lophatherum gracile Brongn. (L. gracile) has been used for food and medicine in China for thousands of years. Flavonoids are one of the main bioactive components of this herb. A reliable method was established using liquid chromatography with tandem mass spectrometry to determine the concentrations of seven flavonoids. The separation was performed using a C18 column at 40°C and the mobile phase was a mixture of methanol and 0.3% formic acid (v/v) in water in gradient elution mode at a flow rate of 1 mL/min. Quantification was performed through tandem mass spectrometry with negative electrospray ionization and multiple reaction monitoring at m/z [M-H]−. The method was validated using calibration curves, limits of detection and quantification, precision, repeatability, stability, and accuracy. Seven compounds in eleven samples were determined, and there were significant differences in the concentrations of isoorientin, swertiajaponin, afzelin, luteolin-7-O-β-D-glucoside, vitexin, isovitexin, and swertisin. The established method is suitable for quality control for the analysis of L. gracile, as well as to provide necessary information for the rational utilization of L. gracile resources.

Synthesis, Biological Evaluation, and Pharmacokinetic Study of Novel Liguzinediol Prodrugs

Liguzinediol (LZDO) ester prodrugs 3–5 were synthesized and evaluated in vitro and in vivo for their potential use in prolonging the half-life of the parent drug LZDO (1a) in vivo. Prodrugs 3–5 were found to display a potent positive inotropic effect on the myocardium, without the risk of arrhythmia. Prodrugs 3–5 rapidly underwent enzymatic hydrolysis to release the parent compound LZDO in 1–3 h in rat liver microsomes and rat plasma. The half-life of the parent compound was prolonged after intragastric administration of prodrug 3, which was found to be a superior prodrug candidate for increasing myocardial contractility.

Influence of sulfur fumigation on the chemical profiles of Atractylodes macrocephala Koidz. evaluated by UFLC–QTOF–MS combined with multivariate statistical analysis

&NA; In the present study, the chemical compositions of Atractylodes macrocephala Koidz. (AMK) were analyzed systematically and influence of sulfur fumigation on the chemical profiles was evaluated by ultrafast flow liquid chromatography coupled with quadrupole‐time‐of‐flight mass spectrometry (UFLC–QTOF–MS) combined with multivariate statistical analysis. 52 components were detected from non‐fumigated AMK (NF‐AMK) and 28 components were newly produced after sulfur fumigation, out of which 59 major peaks were identified. The concentrations of 20 compounds significantly decreased and 37 compounds obviously increased. The potential structural transformation mechanism of terpenoids was explored to illustrate the correlation of the components contents before and after sulfur fumigation. Eight sulfur‐containing/dehydrated‐integrated atractylenolides that evolved from the NF‐AMK were screened out as potential characteristic chemical markers to examine the post‐harvest handling procedures of commercial AMK with excessive sulfur fumigation and maintain consistent quality. HighlightsThe chemical compositions of Atractylodes macrocephala Koidz. (AMK) were analyzed systematically and influence of sulfur fumigation on the chemical profiles was evaluated by UFLC–QTOF–MS combined with multivariate statistical analysis.52 components were examined from non‐fumigated AMK (NF‐AMK) and 28 compounds were newly produced after sulfur fumigation, out of which 59 major peaks were identified.Eight sulfur‐containing/dehydrated‐integrated atractylenolides that evolved from the NF‐AMK were screened out as potential characteristic chemical markers to examine the post‐harvest handling procedures of commercial AMK with excessive sulfur fumigation.

Contents variation analysis of free amino acids, nucleosides and nucleobases in semen sojae praeparatum fermentation using UFLC-QTRAP MS

UFLC-QTRAP MS was used to develop a sensitive and rapid method of evaluating content variation during Semen sojae praeparatum (SSP) fermentation. It did this through the simultaneous quantification of 22 free amino acids and 16 nucleosides and nucleobases in the raw materials and processed products of SSP. The method was shown to be reproducible and accurate. The limits of detection and quantity values were 0.09-168.75 and 0.31-562.50 ng/mL for the 38 analytes, respectively. The data were examined through principal components analysis to compare the content variations. The quantitative results showed that the ingredients were properly determined in most of the samples and were converted regularly throughout the SSP fermentation process. These results correspond to the morphologic changes and principal components analysis results.