Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 33
Filtrar
1.
Sens Diagn ; 3(8): 1344-1352, 2024 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-39129862

RESUMO

In large-scale radiation exposure events, the ability to triage potential victims by the received radiation dosage is crucial. This can be evaluated by radiation-induced biological changes. Radiation-responsive mRNA is a class of biomarkers that has been explored for dose-dependency with methods such as RT-qPCR. However, these methods are challenging to implement for point-of-care devices. We have designed and used molecular beacons as probes for the measurement of radiation-induced changes of intracellular mRNA in a microfluidic device towards determining radiation dosage. Our experiments, in which fixed TK6 cells labeled with a molecular beacon specific to BAX mRNA exhibited dose-dependent fluorescence in a manner consistent with RT-qPCR analysis, demonstrate that such intracellular molecular probes can potentially be used in point-of-care radiation biodosimetry. This proof of concept could readily be extended to any RNA-based test to provide direct measurements at the bedside.

2.
World J Surg Oncol ; 22(1): 182, 2024 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-39010022

RESUMO

BACKGROUND: The efficacy and toxicity of KRASG12C inhibitors were evaluated for advanced solid tumors in several studies; however, the results were not fully consistent. METHODS: Clinical trials evaluating KRASG12C inhibitors for advanced solid tumors were searched from PubMed, Embase, and Cochrane Library online databases up to 31st December 2023. The characteristics of the studies and the results of objective response rate (ORR), disease control rate (DCR), duration of response (DoR), progression-free survival (PFS) rate, overall survival (OS) rate, and treatment-related adverse events (trAEs) were extracted. RESULTS: Ten studies with 925 heavily pretreated advanced patients harboring KRASG12C mutation were included. For total population, the pooled analysis of ORR was 28.6% (95%CI, 21.2-36.6%), DCR was 85.5% (95%CI, 82.2-88.6%), PFS rate at 6 months (PFS6) was 49.6% (95%CI, 41.4-57.9%), PFS rate at 12 months (PFS12) was 26.7% (95%CI, 19.8-34.1%), OS rates at 6 months (OS6) was 76.2% (95%CI, 68.8-82.9%), OS rates at 12 months (OS12) was 47.8% (95%CI, 38.6-57.0%). The pooled analysis of any grade trAEs was 79.3% (95%CI, 66.2-90.0%) and grade three or more trAEs was 24.4% (95%CI, 16.7-32.9%). The median time to response and DoR results from individual data were 1.39 months (95%CI, 1.37-1.41 months) and 10.54 months (95%CI, 7.72-13.36 months). Sotorasib had significantly lower pooled incidences of any trAEs (OR, 0.07, 95%CI, 0.03-0.14) and grade three or more trAES (OR, 0.34, 95%CI, 0.24-0.49) compared with adagrasib. CONCLUSIONS: KRASG12C inhibitors have good ORR, DCR, PFS rate, OS rate, tolerable trAEs, and early response with long duration in advanced solid tumors; however, most of the pooled results were heterogeneous. Sotorasib has shown better safety results.


Assuntos
Mutação , Neoplasias , Proteínas Proto-Oncogênicas p21(ras) , Humanos , Antineoplásicos/uso terapêutico , Antineoplásicos/efeitos adversos , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Prognóstico , Proteínas Proto-Oncogênicas p21(ras)/antagonistas & inibidores , Proteínas Proto-Oncogênicas p21(ras)/genética , Taxa de Sobrevida
3.
Sens Actuators B Chem ; 4012024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38558786

RESUMO

Kinetic measurement plays a crucial role in understanding aptamer binding mechanisms and identifying appropriate aptamers for clinical and research applications. Current techniques, while well established, generally require large sample volumes, bulky and expensive instruments operated by trained personnel, and are hence not readily accessible to resource-limited research laboratories. This paper presents a fluorescence microscopy-based microfluidic assay for measuring aptamer-analyte binding kinetics in a simple and cost-effective manner. Kinetic measurements are achieved by monitoring time-course fluorescence of fluorescently labeled aptamers as they bind to the targets trapped in a microfluidic chip. Fluorescence measurements are performed on a standard fluorescence microscope and are accessible to laboratories with only modest resources. Moreover, microfluidic technology allows efficient and cost-effective immobilization of small amounts of target molecules or live cells as well as flow-based manipulation of aptamers for the measurements. Kinetic measurements of aptamer binding to immunoglobulin E protein and CCRF-CEM cells have yielded results consistent with those obtained from established methods, demonstrating the potential utility of our method for exploring aptamer-target interactions and identifying aptamers that best suit specific given biomedical applications.

4.
J Photochem Photobiol B ; 253: 112877, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38484648

RESUMO

The use of multifunctional nanomedicines in the treatment of tumors is gaining popularity. Here, we constructed a nanodrug delivery system (HA/Au-PDA@CZT) that targets tumors and responds to pH and near-infrared (NIR) dual stimuli. By precisely interacting with an overexpressed CD44 receptor in specific cancer cells, hyaluronic acid (HA) is coated on the Au-PDA NP surface for tumor-targeting abilities. When exposed to NIR radiation, polydopamine (PDA) and gold nanoshells exhibit exceptional photothermal performance that has the potential to both accelerate and kill HLAC 78 head and neck squamous cell carcinoma cells. Antitumor investigations conducted in vivo and in vitro demonstrated that nanomedicine had remarkable synergistic benefits with chemotherapy and photothermal treatment. Only 25.2% of the cells in the HA/Au-PDA@CZT with a NIR irradiation group were viable. Any group's lowest tumor volume was shown in the tumor mice subjected to HA/Au-PDA@CZT with NIR at 0.3 ± 0.1. Consequently, for synergistic chemo-photothermal therapy, our logically designed nanoplatform would be the potential for a head and neck squamous tumor-targeting drug delivery system.


Assuntos
Neoplasias de Cabeça e Pescoço , Nanopartículas , Animais , Camundongos , Linhagem Celular Tumoral , Ouro , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Ácido Hialurônico , Nanopartículas/uso terapêutico , Fototerapia , Carcinoma de Células Escamosas de Cabeça e Pescoço/tratamento farmacológico
5.
Eur Arch Otorhinolaryngol ; 281(3): 1443-1448, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38163817

RESUMO

PURPOSE: To investigate the clinical characteristics of the syndrome of inappropriate antidiuretic hormone (SIADH) associated with nasal and paranasal malignant tumors. METHODS: Patients with locally advanced or recurrence/metastatic malignant tumors of the nasal and paranasal sinuses were included. The SIADH was diagnosed according to the diagnostic criteria. The clinical characteristics of SIADH patients were retrospectively analyzed. RESULTS: Six patients (6/188, 3.2%) met the diagnostic criteria of SIADH, including four olfactory neuroblastoma (4/26, 15.4%), one neuroendocrine carcinoma (1/9, 11.1%), and one squamous cell carcinoma (1/63, 1.6%). Five patients (83.3%) had severe hyponatremia; however, the hyponatremia could be improved by fluid restriction or tolvaptan. Three patients' SIADH were recovered during the chemotherapy and the other three were recovered after the surgery. CONCLUSION: The incidence of SIADH associated with nasal and paranasal malignant tumors is relatively more common in olfactory neuroblastoma and neuroendocrine carcinoma. The hyponatremia caused by SIADH may be corrected by fluid restriction or tolvaptan, and the SIADH may be recovered through anti-tumor therapy.


Assuntos
Carcinoma Neuroendócrino , Estesioneuroblastoma Olfatório , Hiponatremia , Síndrome de Secreção Inadequada de HAD , Neoplasias Nasais , Humanos , Síndrome de Secreção Inadequada de HAD/complicações , Síndrome de Secreção Inadequada de HAD/diagnóstico , Hiponatremia/etiologia , Hiponatremia/complicações , Tolvaptan/uso terapêutico , Estesioneuroblastoma Olfatório/complicações , Estudos Retrospectivos , Carcinoma Neuroendócrino/complicações , Neoplasias Nasais/complicações , Cavidade Nasal
6.
Cancer Med ; 12(20): 20277-20286, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37814950

RESUMO

BACKGROUND: Immune checkpoint inhibitors (ICIs) showed antitumor activity for recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC). However, the results from different studies were controversial. METHODS: Online databases were searched for randomized clinical trials (RCTs) evaluating ICIs for R/M HNSCC. The characteristics of the studies and the results of overall survival (OS), progression-free survival (PFS), objective response rate (ORR), treatment-related adverse events (TRAEs) were extracted. RESULTS: A total of 4936 patients from eight studies were included. Anti-PD1/PDL1 monotherapy significantly improved OS in total population (hazard ratio, HR, 0.87, 95% CI, 0.79-0.95, p = 0.003) and PD-L1 high expression patients (HR, 0.71, 95% CI, 0.55-0.90, p = 0.006) with significant lower incidence of any grade TRAEs (odds ratio, OR, 0.16, 95% CI, 0.07-0.37, p < 0.00001) and Grades 3-5 TRAEs (OR, 0.18, 95% CI, 0.10-0.33, p < 0.0001) compared with standard of care (SOC); however, the pooled results of PFS and ORR were not significant different. PD1/PDL1 inhibitors plus CTLA4 inhibitors did not improve OS, PFS, ORR compared with SOC or ICIs monotherapy; however, the incidence of Grades 3-5 TRAEs was significant higher compared with ICIs monotherapy (OR, 1.80, 95% CI, 1.34-2.41, p = 0.0001). CONCLUSIONS: Anti-PD1/PDL1 monotherapy could improve OS for R/M HNSCC with significant lower incidence of TRAEs compared with SOC. PD1/PDL1 inhibitors plus CTLA4 inhibitors showed no more benefit compared with both SOC and ICIs monotherapy, but the incidence of Grades 3-5 TRAEs was significant higher compared with ICIs monotherapy.


Assuntos
Carcinoma , Neoplasias de Cabeça e Pescoço , Humanos , Carcinoma de Células Escamosas de Cabeça e Pescoço/tratamento farmacológico , Inibidores de Checkpoint Imunológico/efeitos adversos , Antígeno CTLA-4 , Ensaios Clínicos Controlados Aleatórios como Assunto , Neoplasias de Cabeça e Pescoço/tratamento farmacológico
7.
Int J Biol Macromol ; 248: 125713, 2023 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-37437676

RESUMO

Considerable research has been devoted to finding a cost-effective chromatographic matrix with efficient adsorption and high throughput. Wood exhibits complex micro-network structures that make it a powerful contender for a novel environment-friendly chromatographic matrix material. We demonstrate a novel strategy to manufacture a wood monolithic column, which chemically modified the wood and imported diethyl aminoethyl, diethylamine, and amino groups. This wood monolithic column can maintain fully monolithic column performances and highly selective to spike glycoprotein of SARS-CoV-2 by ion exchange force. The wood monolithic column was evaluated by static adsorption, dynamic adsorption, and frontal analysis. The results showed that the static adsorption capacity of the wood monolithic column with 2-diethylaminoethylchloride hydrochloride for bovine serum albumin was 14.72 mg/g, and the adsorption process was chemisorption. In addition, it retained 80 % adsorption capacity after 110 repeated adsorption-elution cycles.


Assuntos
COVID-19 , SARS-CoV-2 , Porosidade , Madeira , Glicoproteína da Espícula de Coronavírus , Glicoproteínas
8.
Int Immunopharmacol ; 112: 109249, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36152537

RESUMO

Endothelial cell protein C receptor (EPCR) is a 46 kDa transmembrane protein receptor, expressed in most immune cells (T cells, monocytes, dendritic cells, polymorphonuclear neutrophils [PMN]). EPCR reportedly plays a vital role in rheumatoid arthritis (RA). Our results confirmed that EPCR expression exists in the PMN of RA patients, and animal experiments demonstrated that down-regulation of EPCR expression affects disease progression in collagen-induced arthritis (CIA) mice. PMN is the immune cell type that first enters the site of inflammation in the early stages of inflammation. In the early stage of RA, PMN cells migrate into the joint cavity and function in the process of RA synovial inflammation, aggravating the bone destruction found in RA and mediating the progression of RA disease progression. We verified the differences in EPCR expression in PMN cells between RA and osteoarthritis (OA) patients by Western blot and then confirmed this difference in animals. We found that CIA mice treated with PMN-neutralizing antibody intervention had reduced disease performance. On this basis, EPCR was knocked down at the same time. The therapeutic effect of PMN-neutralizing antibody treatment was subsequently diminished. To explore the relationship between EPCR and PMN in RA, we used immunofluorescence to detect the expression of PMN-neutrophil extracellular traps (NETs) in RA patients and used EPCR neutralizing antibodies as an intervention. The results showed that the formation of PMN-NETs in RA patients increased. Finally, through in vitro intervention experiments involving EPCR and PMN transcriptome analysis of the peripheral blood of RA patients, we concluded that EPCR may regulate the formation of PMN-NETs in RA patients through the activated protein C (APC)-EPCR signaling pathway, thereby affecting the progression of disease in RA patients.


Assuntos
Artrite Experimental , Artrite Reumatoide , Armadilhas Extracelulares , Camundongos , Animais , Armadilhas Extracelulares/metabolismo , Proteína C , Receptor de Proteína C Endotelial , Neutrófilos , Inflamação , Anticorpos Neutralizantes , Progressão da Doença
9.
Chem Commun (Camb) ; 58(17): 2906-2909, 2022 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-35137770

RESUMO

A novel 3D core-shell material composed of polyacrylate carboxyl microspheres (PCMs) and ZIF-8 nanoparticles was used to promote proton conduction in the Nafion matrix. The Nafion/ZIF-8@PCM membranes displayed excellent proton conductivity (0.24 S cm-1) and physicochemical properties due to special structural characteristics. More importantly, this new concept has a strong practical guiding significance for the fabrication of novel PEMs.


Assuntos
Fontes de Energia Bioelétrica , Polímeros de Fluorcarboneto/química , Estruturas Metalorgânicas/química , Microesferas , Prótons , Nanopartículas/química , Tamanho da Partícula , Zeolitas/química
10.
Chem Commun (Camb) ; 57(73): 9288-9291, 2021 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-34519323

RESUMO

A green biopolymer, lignosulfonate acid (LSA), was first used as an additive in the Nafion membrane for fuel cell applications. The Nafion/LSA composite membrane displayed enhanced thermal stability and other satisfactory properties due to the stable aromatic groups and multiple active sites of LSA. More importantly, the cost-effectiveness and simple fabrication of such novel composite PEMs make their use in PEMFCs very attractive and economical.

11.
ACS Biomater Sci Eng ; 7(8): 3764-3773, 2021 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-34213326

RESUMO

In tumor therapy, polymer nanoparticles are ideal drug delivery materials because they can mask the disadvantages of anti-tumor drugs such as poor solubility in water, high toxicity, and side effects. However, most polymer-based nanoparticles do not themselves have anti-tumor properties. Herein, a novel pH-sensitive nanoparticle drug delivery system based on Ganoderma lucidum polysaccharides (GLPs), which have demonstrated anti-tumor activities, was designed to enable the delivery of methotrexate (MTX) and 10-hydroxycamptothecin (HCPT) to tumor cells, where they could exert synergistic anti-tumor effects. The prepared nanoparticles were irregularly spherical in shape with a uniform particle size of ∼190 nm, and they exhibited a high drug-loading capacity (MTX 21.5% and HCPT 22.6%) and excellent biocompatibility. Moreover, the loaded MTX and HCPT units were rapidly released under acidic conditions within the tumor cells while remaining stable under normal physiological conditions. Meanwhile, compared to free MTX and HCPT, the GLP-APBA-MTX/HCPT nanoparticles presented exhibited better tumor suppressive effects and fewer side effects in vivo, which indicates that they may be an effective anti-tumor treatment strategy.


Assuntos
Antineoplásicos , Nanopartículas , Reishi , Concentração de Íons de Hidrogênio , Metotrexato , Polissacarídeos
12.
ACS Omega ; 6(15): 9998-10004, 2021 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-34056155

RESUMO

Pharmaceutical science based on biological nanotechnology is developing rapidly in parallel with the development of nanomaterials and nanotechnology in general. Pectin is a natural polysaccharide obtainable from a wide range of sources. Here, we show that doxorubicin (DOX)-conjugated hydrophilic pectin (PET) comprising an amphiphilic polymer loaded with hydrophobic dihydroartemisinin (DHA) self-assemble into nanoparticles. Importantly, conjugated DOX and DHA could be released quickly in a weakly acidic environment by cleavage of the acid-sensitive acyl hydrazone bond. Confocal microscopy and flow cytometry confirmed that these PET-DOX/DHA nanoparticles efficiently delivered DOX into the nuclei of MCF-7 cells. Significant tumor growth reduction was monitored in a female C57BL/6 mouse model, showing that the PET-DOX/DHA nanoparticle-mediated drug delivery system inhibited tumor growth and may improve therapy. Thus, we have demonstrated that pectin may be useful in the design of materials for biomedical applications.

13.
Biosens Bioelectron ; 180: 113088, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33647790

RESUMO

Serial measurement of a large panel of protein biomarkers near the bedside could provide a promising pathway to transform the critical care of acutely ill patients. However, attaining the combination of high sensitivity and multiplexity with a short assay turnaround poses a formidable technological challenge. Here, the authors develop a rapid, accurate, and highly multiplexed microfluidic digital immunoassay by incorporating machine learning-based autonomous image analysis. The assay has achieved 12-plexed biomarker detection in sample volume <15 µL at concentrations < 5 pg/mL while only requiring a 5-min assay incubation, allowing for all processes from sampling to result to be completed within 40 min. The assay procedure applies both a spatial-spectral microfluidic encoding scheme and an image data analysis algorithm based on machine learning with a convolutional neural network (CNN) for pre-equilibrated single-molecule protein digital counting. This unique approach remarkably reduces errors facing the high-capacity multiplexing of digital immunoassay at low protein concentrations. Longitudinal data obtained for a panel of 12 serum cytokines in human patients receiving chimeric antigen receptor-T (CAR-T) cell therapy reveals the powerful biomarker profiling capability. The assay could also be deployed for near-real-time immune status monitoring of critically ill COVID-19 patients developing cytokine storm syndrome.


Assuntos
COVID-19/imunologia , Citocinas/análise , Processamento de Imagem Assistida por Computador/métodos , Imunoensaio/métodos , Aprendizado de Máquina , Análise em Microsséries/métodos , Técnicas Analíticas Microfluídicas/métodos , SARS-CoV-2 , Síndrome da Liberação de Citocina , Humanos , Imunoterapia Adotiva , Redes Neurais de Computação
14.
ACS Appl Bio Mater ; 4(2): 1499-1507, 2021 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-35014499

RESUMO

A tumor-penetrating peptide, iRGD (a tumor-homing peptide, CRGDKGPDC), could enhance the penetration of drugs via the specific receptor-binding affinity to αvß3 and NRP-1 that overexpressed on tumor vasculature and tumor cells. Considering the side effects of traditional chemotherapy, here, poly(ethylene glycol) (PEG, Mw = 7500)-based and iRGD-modified poly(ethylene glycol)-based nanoparticles were successfully prepared. iRGD, as a tumor-targeting and tumor-penetrating agent, was combined with PEG after the esterification reaction between PEG and diosgenin (DGN). After the efficient loading of 10-hydroxycamptothecin (HCPT), the iRGD-PEG-DGN/HCPT NPs of chemotherapy were established. The characteristics of iRGD-PEG-DGN/HCPT NPs were evaluated. This nano-delivery system possessed high drug loading efficiency (∼17.34 wt % HCPT), controlled release rate, good pH response, and iRGD active targeting and passive targeting with an appropriate size (∼140 nm). All these features forcefully indicated that the iRGD-modified drug delivery system could markedly ameliorate the tumor therapy efficacy compared to the nontargeted nanoparticles through enhancing the tumor accumulation and penetration.


Assuntos
Antineoplásicos/uso terapêutico , Sistemas de Liberação de Medicamentos/métodos , Nanopartículas/metabolismo , Polímeros/metabolismo , Antineoplásicos/farmacologia , Humanos
15.
J Chromatogr Sci ; 59(2): 175-181, 2021 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-33264388

RESUMO

Separation of natural compounds directly from the crude extract is a challenging work for traditional column chromatography. In the present study, an efficient method for separation of three main compounds from the crude extract of Dracocephalum tanguticum has been successfully established by high-speed counter-current chromatography (HSCCC). The crude extract was directly introduced into HSCCC by using dimethyl sulfoxide as cosolvent. Ethyl acetate/n-butyl alcohol/0.3% glacial acetic acid (4: 1: 5, v/v) system was used and three target compounds with purity higher than 80% were obtained. Preparative HPLC was used for further purification and three target compounds with purity higher than 98% were obtained. The compounds were identified as chlorogenic acid, pedaliin and pedaliin-6″-acetate.


Assuntos
Distribuição Contracorrente/métodos , Lamiaceae/química , Extratos Vegetais/química , Benzopiranos/análise , Ácido Clorogênico/análise , Cromatografia Líquida de Alta Pressão/métodos , Dimetil Sulfóxido/química , Solventes/química
16.
Redox Biol ; 37: 101728, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32961442

RESUMO

Hyperglycemia-induced endothelial endoplasmic reticulum (ER) stress is implicated in the pathophysiology of diabetes and its vascular complications. Procyanidins are enriched in many plant foods and have been demonstrated to exert several beneficial effects on diabetes, cardiovascular and other metabolic diseases. In the present study, we investigated the effect of procyanidin B2 (PCB2), the most widely distributed natural procyanidin, on ER stress evoked by high glucose in endothelial cells (ECs) and the underlying mechanisms. We showed that PCB2 mitigated the high glucose-activated ER stress pathways (PERK, IRE1α and ATF6) in human vascular ECs. In addition, we found that PCB2 attenuated endothelial ER stress via the activation of peroxisome proliferator-activated receptor δ (PPARδ). We demonstrated that PCB2 directly bound to and activated PPARδ. Conversely, GSK0660, a selective PPARδ antagonist, attenuated the suppressive effect of PCB2 on the ER stress signal pathway. Functionally, PCB2 ameliorated the high glucose-impaired endothelium-dependent relaxation in mouse aortas. The protective effect of PCB2 on vasodilation was abolished in the aortas pretreated with GSK0660 or those from the EC-specific PPARδ knockout mice. Moreover, the protective effects of PCB2 on ER stress and endothelial dysfunction required the inter-dependent actions of PPARδ and AMPK. Collectively, we demonstrated that PCB2 mitigated ER stress and ameliorated vasodilation via a PPARδ-mediated mechanism beyond its classic action as a scavenger of free radicals. These findings further highlighted the novel roles of procyanidins in intervening the ER stress and metabolic disorders related to endothelial dysfunction.


Assuntos
PPAR delta , Proantocianidinas , Animais , Biflavonoides , Catequina , Estresse do Retículo Endoplasmático , Endorribonucleases , Células Endoteliais , Endotélio Vascular , Camundongos , PPAR delta/genética , Proantocianidinas/farmacologia , Proteínas Serina-Treonina Quinases
17.
J Sep Sci ; 43(19): 3748-3755, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32729215

RESUMO

Five flavonoids with similar polarity were obtained from Caragana korshinskii Kom. by preparative high speed counter-current chromatography. Due to their similar polarity, it is difficult to select a suitable solvent system for one-step separation. Three fractions including one pure compound were only obtained with a relatively suitable solvent system of ethyl acetate: n-butanol:water (0.5% glacial acetic acid) (4:6:10, v:v:v). In order to improve the separation efficiency, recycling and heart cut modes were introduced. As a result, two flavonoids with separation factor value at 1.13 and the other two with separation factor value at 1.20 were successfully separated. Finally, five flavonoids with purity higher than 98% were obtained. Fortunately, a new compound named myricetin 3'-methyl ether 3-O-glucoside-7-O-rhamnoside was obtained. The results indicated that the recycling combined with heart-cut mode could be effective for the preparation of natural compounds with similar polarity.


Assuntos
Caragana/química , Distribuição Contracorrente/métodos , Flavonoides/análise , Extratos Vegetais/análise
18.
Zhongguo Zhong Yao Za Zhi ; 45(4): 955-960, 2020 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-32237499

RESUMO

The standard sample of natural products is an essential standard reference to determine the quality of the product in the quality control of natural products. To develop a certified reference material(CRM) of swertioside according to the Work Guideline for Reference Materials(3): Reference Material-General Principles and Statistical Method for Certification(GB/T 15000.3-2008), swertioside was purified from whole plant of Swertia mussotii by extraction, isolation and Prep-HPLC to obtain certified reference material of swertioside. The structure of swertioside was identified by IR, UV, high-resolution MS, NMR. Thin layer chromatography, optical rotation, elemental analysis and melting point was carried out for the identification. The purity of the prepared sample was tested from different chromatographic elution conditions, thin layer chromatography and HPLC-MS. Swertioside was divided into 140 bottles, with 10 mg per bottle after homogeneity test, stability test and quantitative analysis. This CRM is 7-O-[α-L-rhamnopyranosyl-(1→2)-ß-D-xylopyranosyl]; the homogeneity of the 95% confidence interval was good; the certified purity value was 98.66%, with a relative expanded uncertainty of 0.38%; the storage period was 36 months at 0-8 ℃. Therefore, the CRM of sakuranetin reached the technical requirements of CRM, and was accepted by SAC. Swertioside is successfully developed and can be used for determining content, evaluating test methods, detecting relevant products and controlling quality.


Assuntos
Compostos Fitoquímicos/normas , Swertia/química , Certificação , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas , Padrões de Referência
19.
J Chromatogr Sci ; 58(3): 211-216, 2020 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-32099992

RESUMO

Oxytropis falcata Bunge, known as "the King of Herbs" in Tibetan medicine, is used for treatment of hyperpyrexia, pain, wounds, inflammation and anthrax. However, it is difficult to isolate compound with high-purity from O. falcata because of its complexity. In this work, an efficient method was successfully established for the separation of 3-hydroxy-3-methylglutaryl (HMG) flavonoid glycosides from O. falcata by 2D preparative chromatography (2D-HPLC). An ODS C18 preparative column was used for the first-dimension preparation, and the XCharge C18 preparative column with different separation selectivity to the ODS C18 stationary phase was used for the second-dimension preparation. Four HMG flavonoid glycosides (oxytroflavosides A-D) and two flavonoid glycosides (oxytroflavosides F and G) were separated with purities over 98%. Their structures were elucidated by nuclear magnetic resonance spectroscopy. The 2D-HPLC method used in this study is effective for preparative separation of HMG flavonoid glycosides from O. falcata. Additionally, this method shows great potential for the separation of flavonoid glycosides from other plant extracts.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Flavonoides/isolamento & purificação , Glicosídeos/isolamento & purificação , Oxytropis/química , Flavonoides/química , Glicosídeos/química , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Extratos Vegetais/química
20.
J Sep Sci ; 42(20): 3191-3199, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31444948

RESUMO

In the present study, combined chromatographic strategy based on macroporous resin, high-speed counter-current chromatography and preparative high-performance liquid chromatography for systematic separation of antioxidants from crude samples guided by high-performance liquid chromatography with 1,1-diphenyl-2-picrylhydrazyl has been successfully established. Based on this strategy, seven antioxidants including isorugosin A, ß -1,2,3,6-tetragalloyl-D-glucose, chebulinic acid, 1,2,3,4,6-penta-O-galloyl-ß -D-glucose, chebulagic acid, ethyl gallate, and gallic acid were obtained from the fruit of Terminalia billerica. First, high-performance liquid chromatography with 1,1-diphenyl-2-picrylhydrazyl experiment showed the presence of seven main antioxidants in the crude extract of the fruit of Terminalia billerica. Then, a macroporous resin column chromatography method was developed for the enrichment of these seven antioxidants. Finally, an efficient method based on high-speed counter-current chromatography and preparative high-performance liquid chromatography was developed for the separation of these antioxidants. In the selection of solvent systems, it was found that acetic acid could be a good regulator for modifying the partition coefficient values of tannins. The present study provides a reference for systematic separation of antioxidants from crude samples. Considering the general existence of antioxidants in crude samples, this combined chromatographic strategy might lead to broader application prospects.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA