Tea is a widely consumed beverage and has many important physiological properties and potential health benefits. In this study, a novel method based on supercritical fluid chromatography coupled with mass spectrometry...Tea is a widely consumed beverage and has many important physiological properties and potential health benefits. In this study, a novel method based on supercritical fluid chromatography coupled with mass spectrometry (SFC-MS) was developed to simultaneously determine 11 amino acids in different types of tea (green teas, Oolong tea, black tea and Pu-erh tea). The separation conditions for the analysis of the selected amino acids including the column type, temperature and backpressure as well as the type of additive, were carefully optimized. The best separation of the 11 amino acids was obtained by adding water (5%, v/v) and trifluoroacetic acid (0.4%, v/v) to the organic modifier (methanol). Finally, the developed SFC-MS method was fully validated and successfully applied to the determination of these amino acids in six different tea samples. Good linearity (r ≥ 0.993), precision (RSDs≤ 2.99%), accuracy (91.95%-107.09%) as well as good sample stability were observed. The limits of detection ranged from 1.42 to 14.69 ng/mL, while the limits of quantification were between 4.53 and 47.0 ng/mL. The results indicate that the contents of the 11 amino acids in the six different tea samples are greatly influenced by the degree of fermentation. The proposed SFC-MS method shows a great potential for further investigation of tea varieties.展开更多
An analytical methodology based on an O-[2-(methacryloyloxy)-ethylcarbamoyl]-10,11-dihydroquinidine(MQD)-silica hybrid monolithic column was developed for the enantioseparation of 9-fluorenylmethoxycarbonyl(FMOC)deriv...An analytical methodology based on an O-[2-(methacryloyloxy)-ethylcarbamoyl]-10,11-dihydroquinidine(MQD)-silica hybrid monolithic column was developed for the enantioseparation of 9-fluorenylmethoxycarbonyl(FMOC)derivatized amino acids by nano-liquid chromatography.The mobile phase was optimized including the apparent pH,content of ACN,and concentration of the buffer to obtain a satisfactory enantioresolution performance.27 FMOC derivatized amino acids including 19 protein and 8 non-protein amino acids were tested,and 19 out of them were enantiomerically discriminated obtaining baseline separation for 11 of them.Analytical characteristics of the method were evaluated for norvaline and tryptophan in terms of linearity,precision,accuracy,limits of detection(LOD)and quantitation(LOQ)showing good performance to be applied to the enantiomeric determination of these amino acids in dietary supplements.LOD and LOQ values were 9.3 and 31 mM for norvaline enantiomers and 7.5 and 25 mM for tryptophan enantiomers,respectively.The contents of D-norvaline and D-tryptophan were below their respective LODs in all the analyzed samples.Quantitation of L-tryptophan and L-norvaline showed good agreement with the labeled contents except for one sample which did not show presence of L-norvaline,contrary to the label indication.展开更多
In this research,a new phospholipid based monolith was fabricated by in situ co-polymerization of 1-dodecanoyl-2-(11-methacrylamidoundecanoyl)-sn-glycero-3-phosphoethanolamine and ethylene dimethacrylate to mimick bio...In this research,a new phospholipid based monolith was fabricated by in situ co-polymerization of 1-dodecanoyl-2-(11-methacrylamidoundecanoyl)-sn-glycero-3-phosphoethanolamine and ethylene dimethacrylate to mimick bio-membrane environment.Excellent physicochemical properties of this novel monolith that were achieved included column efficiency,stability,and permeability.Moreover,the biomimetic monolith showed outstanding separation capability for a series of intact proteins and small molecules.In particular,it exhibited good potential as an alternative to the commercial immobilized artificial membrane(IAM)column(IAM.PC.DD2)for studying drug-membrane interactions.This study not only enriched the types of IAM stationary phases,but also provided a simple model for the prediction of phosphatidylethanolamine related properties of drug candidates.展开更多
Zwitterionic sulfobetaine-based monolithic stationary phases have attracted increasing attention for their use in hydrophilic interaction chromatography.In this study,a novel hydrophilic polymeric monolith was fabrica...Zwitterionic sulfobetaine-based monolithic stationary phases have attracted increasing attention for their use in hydrophilic interaction chromatography.In this study,a novel hydrophilic polymeric monolith was fabricated through photo-initiated copolymerization of 3-(3-vinyl-1-imidazolio)-1-propanesulfonate(SBVI)with pentaerythritol triacrylate using methanol and tetrahydrofuran as the porogenic system.Notably,the duration for the preparation of this novel monolith was as little as 5 min,which was significantly shorter than that required for previously reported sulfobetaine-based monoliths prepared via conventional thermally initiated copolymerization.Moreover,these monoliths showed good morphology,permeability,porosity(62.4%),mechanical strength(over 15 MPa),column efficiency(51,230 plates/m),and reproducibility(relative standard deviations for all analytes were lower than 4.6%).Mechanistic studies indicated that strong hydrophilic and negative electrostatic interactions might be responsible for the retention of polar analytes on the zwitterionic SBVI-based monolith.In particular,the resulting monolith exhibited good anti-protein adhesion ability and low nonspecific protein adsorption.These excellent features seem to favor its application in bioanalysis.Therefore,the novel zwitterionic sulfobetaine-based monolith was successfully employed for the highly selective separation of small bioactive compounds and the efficient enrichment of N-glycopeptides from complex samples.In this study,we prepared a novel zwitterionic sulfobetaine-based monolith with good performance and developed a simpler and faster method for preparation of zwitterionic monoliths.展开更多
Due to low immobilized ligand density,limited binding capacity,and severe interference from serum proteins,developing ideal peptide-based biomaterials for precise recognition and in vivo analysis of biopharmaceuticals...Due to low immobilized ligand density,limited binding capacity,and severe interference from serum proteins,developing ideal peptide-based biomaterials for precise recognition and in vivo analysis of biopharmaceuticals remains a huge challenge.In this study,mimotope peptide modified pompon mum-like biomimetic magnetic microparticles(MMPs,3.8μm)that mimic the specific functionalities of CD20 on malignant B cells were developed for the first time.Benefit from the numerous ligand binding sites(Ni^(2+))on the pompon mum-like MMPs,these novel materials achieved≥10 times higher peptide ligand densities(>2300 mg/g)and antibody binding capacities(1380 mg/g)compared to previous reported biomaterials.Leveraging the high specificity of the mimotope peptide,rituximab can be precisely recognized and enriched from cell culture media or serum samples.We also established an LC-MS/MS method using the MMPs for tracking rituximab biotransformation in patient serum.Intriguingly,deamidation of Asn55 and Asn33,as well as oxidation of Met81 and Met34 were observed at the key complementarity determining regions of rituximab,which could potentially influence antibody function and require careful monitoring.Overall,these versatile biomimetic MMPs demonstrate superior recognition and enrichment capabilities for target antibodies,offering interesting possibilities for biotransformation analysis of biopharmaceuticals in patient serum.展开更多
Neuraminidase inhibitors(NAIs)are the mainstay antiviral drugs against influenza infection.In this study,a ligand fishing protocol was developed to screen NAIs using neuraminidase immobilized magnetic beads(NA-MB).Aft...Neuraminidase inhibitors(NAIs)are the mainstay antiviral drugs against influenza infection.In this study,a ligand fishing protocol was developed to screen NAIs using neuraminidase immobilized magnetic beads(NA-MB).After verifying the feasibility of NA-MB with an artificial mixture including NA inhibitors and non-inhibitors,the developed ligand fishing protocol was applied to screen NAIs from the crude extracts of Duchesnea indica Andr.Twenty-four NA binding compounds were identified from the normal butanol(n-BuOH)extract of D.indica as potential NAIs by high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(HPLC-Q-TOF-MS)assisted with Compound Structure Identification(CSI):FingerID,including 12 ellagitannins,4 brevifolin derivatives,3 ellagic acid derivatives,and 4 flavonoids.Among them,9 compounds were isolated and tested for in vitro NA inhibitory activities against NA from Clostridium perfringens,and from oseltamivir sensitive and resistant influenza A virus strains.The results indicate that compound B23 has the NA inhibitory activities in both the oseltamivir sensitive and resistant viral NA,with half maximal inhibitory concentration(IC50)values of 197.9 and 125.4μmol/L,respectively.Moreover,B23 can obviously reduce the replication of oseltamivir sensitive and resistant viruses in Madin-Darby canine kidney(MDCK)cells at the concentrations of 40 and 200μmol/L.展开更多
Nature has produced a rich diversity of structurally complex compounds or secondary metabolites with a wide variety of biological activities.Natural products have long been exploited for therapeutic purposes in tradit...Nature has produced a rich diversity of structurally complex compounds or secondary metabolites with a wide variety of biological activities.Natural products have long been exploited for therapeutic purposes in traditional medicines around the world.Recently,it was reported almost half of the 1562 new approved drugs introduced between 1981 and 2014 are natural products or derived from natural products or biological^1.展开更多
Human monoamine oxidase B (hMAO-B) has emerged as a pivotal therapeutic target for Parkinson's disease. Due to adverse effects and shortage of commercial drugs, there is a need for novel, highly selective, and rev...Human monoamine oxidase B (hMAO-B) has emerged as a pivotal therapeutic target for Parkinson's disease. Due to adverse effects and shortage of commercial drugs, there is a need for novel, highly selective, and reversible hMAO-B inhibitors with good blood-brain barrier permeability. In this study, a high-throughput at-line nanofractionation screening platform was established with extracts from Chuanxiong Rhizoma, which resulted in the discovery of 75 active compounds, including phenolic acids, volatile oils, and phthalides, two of which were highly selective novel natural phthalide hMAO-B inhibitors that were potent, selective, reversible and had good blood‒brain permeability. Molecular docking and molecular dynamics simulations elucidated the inhibition mechanism. Sedanolide (IC50 = 103 nmol/L;SI = 645) and neocnidilide (IC50 = 131 nmol/L;SI = 207) demonstrated their excellent potential as hMAO-B inhibitors. They offset the limitations of deactivating enzymes associated with irreversible hMAO-B inhibitors such as rasagiline. In SH-SY5Y cell assays, sedanolide (EC50 = 0.962 μmol/L) and neocnidilide (EC50 = 1.161 μmol/L) exhibited significant neuroprotective effects, comparable to the positive drugs rasagiline (EC50 = 0.896 μmol/L) and safinamide (EC50 = 1.079 μmol/L). These findings underscore the potential of sedanolide as a novel natural hMAO-B inhibitor that warrants further development as a promising drug candidate.展开更多
基金the financial support from China Postdoctoral Science Foundation(2018M643205)
文摘Tea is a widely consumed beverage and has many important physiological properties and potential health benefits. In this study, a novel method based on supercritical fluid chromatography coupled with mass spectrometry (SFC-MS) was developed to simultaneously determine 11 amino acids in different types of tea (green teas, Oolong tea, black tea and Pu-erh tea). The separation conditions for the analysis of the selected amino acids including the column type, temperature and backpressure as well as the type of additive, were carefully optimized. The best separation of the 11 amino acids was obtained by adding water (5%, v/v) and trifluoroacetic acid (0.4%, v/v) to the organic modifier (methanol). Finally, the developed SFC-MS method was fully validated and successfully applied to the determination of these amino acids in six different tea samples. Good linearity (r ≥ 0.993), precision (RSDs≤ 2.99%), accuracy (91.95%-107.09%) as well as good sample stability were observed. The limits of detection ranged from 1.42 to 14.69 ng/mL, while the limits of quantification were between 4.53 and 47.0 ng/mL. The results indicate that the contents of the 11 amino acids in the six different tea samples are greatly influenced by the degree of fermentation. The proposed SFC-MS method shows a great potential for further investigation of tea varieties.
文摘An analytical methodology based on an O-[2-(methacryloyloxy)-ethylcarbamoyl]-10,11-dihydroquinidine(MQD)-silica hybrid monolithic column was developed for the enantioseparation of 9-fluorenylmethoxycarbonyl(FMOC)derivatized amino acids by nano-liquid chromatography.The mobile phase was optimized including the apparent pH,content of ACN,and concentration of the buffer to obtain a satisfactory enantioresolution performance.27 FMOC derivatized amino acids including 19 protein and 8 non-protein amino acids were tested,and 19 out of them were enantiomerically discriminated obtaining baseline separation for 11 of them.Analytical characteristics of the method were evaluated for norvaline and tryptophan in terms of linearity,precision,accuracy,limits of detection(LOD)and quantitation(LOQ)showing good performance to be applied to the enantiomeric determination of these amino acids in dietary supplements.LOD and LOQ values were 9.3 and 31 mM for norvaline enantiomers and 7.5 and 25 mM for tryptophan enantiomers,respectively.The contents of D-norvaline and D-tryptophan were below their respective LODs in all the analyzed samples.Quantitation of L-tryptophan and L-norvaline showed good agreement with the labeled contents except for one sample which did not show presence of L-norvaline,contrary to the label indication.
基金funded by the National Natural Science Foundation of China(Grant Nos.:81872830 and 82073806)the Natural Science Foundation of Guangdong Province(Grant No.:2020A1515010569)+1 种基金the Science and Technology Innovation Guidance Project of Zhaoqing City(Grant No.:201804030103)the Scientific Research Fund of Zhaoqing University(Grant No.:201817).
文摘In this research,a new phospholipid based monolith was fabricated by in situ co-polymerization of 1-dodecanoyl-2-(11-methacrylamidoundecanoyl)-sn-glycero-3-phosphoethanolamine and ethylene dimethacrylate to mimick bio-membrane environment.Excellent physicochemical properties of this novel monolith that were achieved included column efficiency,stability,and permeability.Moreover,the biomimetic monolith showed outstanding separation capability for a series of intact proteins and small molecules.In particular,it exhibited good potential as an alternative to the commercial immobilized artificial membrane(IAM)column(IAM.PC.DD2)for studying drug-membrane interactions.This study not only enriched the types of IAM stationary phases,but also provided a simple model for the prediction of phosphatidylethanolamine related properties of drug candidates.
基金supported by the National Natural Science Foundation of China(Grant Nos.:82173773 and 82073806)the Natural Science Foundation of Guangdong Province,China(Grant Nos.:2020A1515010569 and 2021A0505030039)Science and Technology Program of Guangzhou,China(Grant No.:202102020729).
文摘Zwitterionic sulfobetaine-based monolithic stationary phases have attracted increasing attention for their use in hydrophilic interaction chromatography.In this study,a novel hydrophilic polymeric monolith was fabricated through photo-initiated copolymerization of 3-(3-vinyl-1-imidazolio)-1-propanesulfonate(SBVI)with pentaerythritol triacrylate using methanol and tetrahydrofuran as the porogenic system.Notably,the duration for the preparation of this novel monolith was as little as 5 min,which was significantly shorter than that required for previously reported sulfobetaine-based monoliths prepared via conventional thermally initiated copolymerization.Moreover,these monoliths showed good morphology,permeability,porosity(62.4%),mechanical strength(over 15 MPa),column efficiency(51,230 plates/m),and reproducibility(relative standard deviations for all analytes were lower than 4.6%).Mechanistic studies indicated that strong hydrophilic and negative electrostatic interactions might be responsible for the retention of polar analytes on the zwitterionic SBVI-based monolith.In particular,the resulting monolith exhibited good anti-protein adhesion ability and low nonspecific protein adsorption.These excellent features seem to favor its application in bioanalysis.Therefore,the novel zwitterionic sulfobetaine-based monolith was successfully employed for the highly selective separation of small bioactive compounds and the efficient enrichment of N-glycopeptides from complex samples.In this study,we prepared a novel zwitterionic sulfobetaine-based monolith with good performance and developed a simpler and faster method for preparation of zwitterionic monoliths.
基金supported by the National Natural Science Foundation of China(82173773,82273893,82373829)the Natural Science Foundation of Guangdong Province,China(2021A0505030039,2021A0505020014)+1 种基金the High-End Foreign Experts Project,China(G2021199005L)the Science and Technology Program of Guangdong Provincial Medical Products Administration,China(2023TDZ11)。
文摘Due to low immobilized ligand density,limited binding capacity,and severe interference from serum proteins,developing ideal peptide-based biomaterials for precise recognition and in vivo analysis of biopharmaceuticals remains a huge challenge.In this study,mimotope peptide modified pompon mum-like biomimetic magnetic microparticles(MMPs,3.8μm)that mimic the specific functionalities of CD20 on malignant B cells were developed for the first time.Benefit from the numerous ligand binding sites(Ni^(2+))on the pompon mum-like MMPs,these novel materials achieved≥10 times higher peptide ligand densities(>2300 mg/g)and antibody binding capacities(1380 mg/g)compared to previous reported biomaterials.Leveraging the high specificity of the mimotope peptide,rituximab can be precisely recognized and enriched from cell culture media or serum samples.We also established an LC-MS/MS method using the MMPs for tracking rituximab biotransformation in patient serum.Intriguingly,deamidation of Asn55 and Asn33,as well as oxidation of Met81 and Met34 were observed at the key complementarity determining regions of rituximab,which could potentially influence antibody function and require careful monitoring.Overall,these versatile biomimetic MMPs demonstrate superior recognition and enrichment capabilities for target antibodies,offering interesting possibilities for biotransformation analysis of biopharmaceuticals in patient serum.
基金financially supported by National Natural Science Foundation,China(81872830,31970884,and U1801287)the International Science&Technology Cooperation Program of Guangzhou,China(201807010022)National Natural Science Foundation of Guangdong Province,China(No.2019A1515011489)
文摘Neuraminidase inhibitors(NAIs)are the mainstay antiviral drugs against influenza infection.In this study,a ligand fishing protocol was developed to screen NAIs using neuraminidase immobilized magnetic beads(NA-MB).After verifying the feasibility of NA-MB with an artificial mixture including NA inhibitors and non-inhibitors,the developed ligand fishing protocol was applied to screen NAIs from the crude extracts of Duchesnea indica Andr.Twenty-four NA binding compounds were identified from the normal butanol(n-BuOH)extract of D.indica as potential NAIs by high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(HPLC-Q-TOF-MS)assisted with Compound Structure Identification(CSI):FingerID,including 12 ellagitannins,4 brevifolin derivatives,3 ellagic acid derivatives,and 4 flavonoids.Among them,9 compounds were isolated and tested for in vitro NA inhibitory activities against NA from Clostridium perfringens,and from oseltamivir sensitive and resistant influenza A virus strains.The results indicate that compound B23 has the NA inhibitory activities in both the oseltamivir sensitive and resistant viral NA,with half maximal inhibitory concentration(IC50)values of 197.9 and 125.4μmol/L,respectively.Moreover,B23 can obviously reduce the replication of oseltamivir sensitive and resistant viruses in Madin-Darby canine kidney(MDCK)cells at the concentrations of 40 and 200μmol/L.
文摘Nature has produced a rich diversity of structurally complex compounds or secondary metabolites with a wide variety of biological activities.Natural products have long been exploited for therapeutic purposes in traditional medicines around the world.Recently,it was reported almost half of the 1562 new approved drugs introduced between 1981 and 2014 are natural products or derived from natural products or biological^1.
基金This work was supported by grants from the National Natural Science Foundation of China(82073806,82304437,82204342,82373835,82173781)The China Postdoctoral Science Foundation(2022M721355,China)the Fundamental Research Funds for the Central Universities(21623343,China).
文摘Human monoamine oxidase B (hMAO-B) has emerged as a pivotal therapeutic target for Parkinson's disease. Due to adverse effects and shortage of commercial drugs, there is a need for novel, highly selective, and reversible hMAO-B inhibitors with good blood-brain barrier permeability. In this study, a high-throughput at-line nanofractionation screening platform was established with extracts from Chuanxiong Rhizoma, which resulted in the discovery of 75 active compounds, including phenolic acids, volatile oils, and phthalides, two of which were highly selective novel natural phthalide hMAO-B inhibitors that were potent, selective, reversible and had good blood‒brain permeability. Molecular docking and molecular dynamics simulations elucidated the inhibition mechanism. Sedanolide (IC50 = 103 nmol/L;SI = 645) and neocnidilide (IC50 = 131 nmol/L;SI = 207) demonstrated their excellent potential as hMAO-B inhibitors. They offset the limitations of deactivating enzymes associated with irreversible hMAO-B inhibitors such as rasagiline. In SH-SY5Y cell assays, sedanolide (EC50 = 0.962 μmol/L) and neocnidilide (EC50 = 1.161 μmol/L) exhibited significant neuroprotective effects, comparable to the positive drugs rasagiline (EC50 = 0.896 μmol/L) and safinamide (EC50 = 1.079 μmol/L). These findings underscore the potential of sedanolide as a novel natural hMAO-B inhibitor that warrants further development as a promising drug candidate.
