Search results for "Xanthene"
showing 10 items of 152 documents
Cytotoxicity of seven naturally occurring phenolic compounds towards multi-factorial drug-resistant cancer cells
2016
Abstract Introduction In medical oncology, multi-drug resistance (MDR) of cancer cells continues to be a major impediment. We are in quest of novel anti-proliferative agents to overcome drug-resistant tumor cells. Methods In the present study, we investigated the cytotoxicity of 7 naturally occurring phenolic compounds including two isoflavonoids alpinumisoflavone ( 1 ) and laburnetin ( 2 ), one biflavonoid amentoflavone ( 3) , three lignans pycnanthulignene A ( 4 ), pycnanthulignene B ( 5 ), and syringaresinol ( 7 ) and one xanthone, euxanthone ( 6 ) against 9 drug-sensitive and MDR cancer cell lines. The resazurin reduction assay was used to evaluate the cytotoxicity of these compounds, w…
CCDC 1557894: Experimental Crystal Structure Determination
2020
Related Article: Luka Ðorđević, Cataldo Valentini, Nicola Demitri, Cécile Mézière, Magali Allain, Marc Sallé, Andrea Folli, Damien Murphy, Samuel Mañas-Valero, Eugenio Coronado, Davide Bonifazi|2020|Angew.Chem.,Int.Ed.|59|4106|doi:10.1002/anie.201914025
CCDC 1557895: Experimental Crystal Structure Determination
2020
Related Article: Luka Ðorđević, Cataldo Valentini, Nicola Demitri, Cécile Mézière, Magali Allain, Marc Sallé, Andrea Folli, Damien Murphy, Samuel Mañas-Valero, Eugenio Coronado, Davide Bonifazi|2020|Angew.Chem.,Int.Ed.|59|4106|doi:10.1002/anie.201914025
Cytotoxicity of 35 medicinal plants from Sudan towards sensitive and multidrug-resistant cancer cells
2015
Abstract Background Cancer is a complex disease with multiple genetic and epigenetic alterations. Since decades, the hallmark of cancer therapy is chemotherapy. Cytotoxic drugs erase rapidly dividing cells without sufficient differentiation between normal and cancerous cells resulting in severe side effects in normal tissues. Recently, strategies for cancer treatment focused on targeting specific proteins involved in tumor growth and progression. The present study was designed to investigate the cytotoxicity of 65 crude extracts from 35 Sudanese medicinal plants towards various cancer cell lines expressing molecular mechanisms of resistance towards classical chemotherapeutics (two ATP-bindi…
Synthesis of novel organic-based fluorophores – Implementation to the design of fluorogenic enzyme substrates based on the principle of in situ synth…
2020
Detection and fluorescence imaging of biologic systems requires the implementation of efficient, robust and easy-to-use tools. Conventional fluorogenic probes currently used in microbiology lack efficiency since they are based on the single chemical modification of a fluorophore bearing an optically tunable reactive group, which often leads to incomplete fluorescence quenching. The main goal of my Ph.D thesis was to develop novel fluorogenic enzymatic substrates based on the "covalent assembly" principle. This approach also named "in situ synthesis" is based on the use of domino reactions to form a fluorescent moiety starting from a "caged" non-fluorescent molecule. In our case, the bioanal…
Flow Cytometric Analysis of Calcium Mobilization in Whole‐Blood Platelets
2003
Flow cytometry provides a convenient method to evaluate platelet activation by following the kinetics of intracellular free Ca2+, using sensitive fluorescent indicators that can be loaded into intact cells. Moreover, in the clinical setting, whole-blood techniques have obvious advantages to avoid artifactual platelet activation and allow the maintenance of near-physiological conditions. This unit describes a fast and sensitive flow cytometric procedure using the Ca2+-sensitive dye fluo-3 AM and the platelet-specific antibody CD41-PE to determine the kinetics of intracellular Ca2+ mobilization in whole-blood platelets with minimal manipulation of the samples. The technique may be applied to …
Stimulation of endothelial nitric oxide synthase by proinsulin C-peptide.
2003
There is increasing evidence for biological functions of human C-peptide. Recently, we have described that proinsulin C-peptide increases nutritive capillary blood flow and restores erythrocyte deformability in type 1 diabetic patients, whereas it has no such effect in non-diabetic subjects. The aim of the current study was to elucidate cellular mechanisms of this vasodilator effect in vitro by measuring the nitric oxide (NO)-mediated increase of cGMP production in a RFL-6 reporter cell assay and by demonstrating endothelial calcium influx with the Fluo-3 technique. C-peptide increased the release of NO from endothelial NO synthase (eNOS) in bovine aortic endothelial cells in a concentratio…
Cytotoxicity of 4-hydroxy-N-(naphthalen-1-yl)-2-oxo-2H-chromene-3-carboxamide in multidrug-resistant cancer cells through activation of PERK/eIF2α/AT…
2021
After decades of research, multidrug resistance (MDR) remains a huge challenge in cancer treatment. In this study, the cytotoxic of 4-hydroxy-N-(naphthalen-1-yl)-2-oxo-2H-chromene-3-carboxamide (MCC1734) has been investigated towards multidrug-resistant cancer cell lines. MCC1734 exerted cytotoxicity on cell lines expressing different mechanisms of drug resistance (P-glycoprotein, BCRP, ABCB5, EGFR, p53 knockout) to a different extent. Interestingly, sensitive CCRF-CEM cells and multidrug-resistant P-gp-overexpressing CEM/ADR5000 cells represented similar sensitivity towards MCC1734, indicating MCC1734 can bypass P-gp-mediated resistance. Microarray-based mRNA expression revealed that MCC17…
Synthesis and Spectroscopic Properties of Silica−Dye−Semiconductor Nanocrystal Hybrid Particles
2010
We prepared silica-dye-nanocrystal hybrid particles and studied the energy transfer from semiconductor nanocrystals (= donor) to organic dye molecules (= acceptor). Multishell CdSe/CdS/ZnS semiconductor nanocrystals were adsorbed onto monodisperse Stöber silica particles with an outer silica shell of thickness 2-23 nm containing organic dye molecules (Texas Red). The thickness of this dye layer has a strong effect on the energy transfer efficiency, which is explained by the increase in the number of dye molecules homogeneously distributed within the silica shell, in combination with an enhanced surface adsorption of nanocrystals with increasing dye amount. Our conclusions were underlined by…
Triplet-triplet energy transfer controlled by the donor-acceptor distance in rigidly held palladium-containing cofacial bisporphyrins.
2005
Eleven new complexes, including mono-, heterobi-, and homobimetallic cofacial bisporphyrins, (Pd)H 2 DPS, (M)H 2 DPX, (M)H 2 DPB, (PdZn)DPS, (PdZn)DPX, (Pt) 2 DPX, (M) 2 DPB (M=Pd, Pt), and (Pt)P (DPS 4 - = 4,6-bis[5-(2,8,13,17-tetraethyl-3,7,12,18-tetramethylporphyrinyl)]dibenzothiophene tetraanion, DPX 4 - = 4,5-bis[5-(2,8,13,17-tetraethyl-3,7,12,18-tetramethylporphyrinyl)]-9,9-dimethylxanthene tetraanion, DPB 4 - =1,8-bis[5-(2,8,13,17-tetraethyl-3,7,12,18-tetramethylporphyrinyl)]biphenylene tetraanion, P 2 - = 5-phenyl-2,8,13,17-tetraethyl-3,7,12,18-tetramethylporphyrin dianion) have been synthesized and characterized. The photophysical properties of the donor (M)P (M=Pd or Pt, P= porphy…