RESUMO
The influence of sample matrix on sample sweeping in MEKC was examined in the presented manuscript. Significant focusing effect was observed for relatively hydrophobic cationic compounds (emetine, strychnine and quinine) using high ionic strength sample matrix (900 mM H3 PO4 /720 mM Tris) which conductivity was about ninefold higher than utilized BGE. Moreover, the results were obtained using BGE composed of comparatively low surfactant concentration (10 mM SDS) and 40 mM H3 PO4 /32 mM Tris buffer solution. About 200 to 300-fold preconcentration of analytes was reached with the presented method. Basing on experimental results and computer simulation using Simul5 software, hypothetical mechanism of observed phenomenon was proposed.
Assuntos
Cromatografia Capilar Eletrocinética Micelar/métodos , Tensoativos/química , Simulação por Computador , Emetina/análise , Emetina/química , Emetina/isolamento & purificação , Interações Hidrofóbicas e Hidrofílicas , Modelos Químicos , Quinina/análise , Quinina/química , Quinina/isolamento & purificação , Estricnina/análise , Estricnina/química , Estricnina/isolamento & purificaçãoRESUMO
A crude organic solvent extract of Alangium cf. longiflorum exhibited potent inhibition of hypoxia-induced HIF-1 transcriptional activity in human U251 glioma cells. Dereplication and bioactivity-guided fractionation, including Sephadex LH-20 and chiral HPLC chromatographies, led to the isolation of tubulosine ( 1), 9-desmethyltubulosine ( 2), and isotubulosine ( 3). Structures were verified by complete (1)H and (13)C assignments using 1D- and 2D-NMR techniques. Tubulosine strongly inhibited HIF-1 transcriptional activity, isotubulosine was devoid of activity, and 9-desmethyltubulosine possessed 6-fold less potency than tubulosine.
Assuntos
Alangiaceae/química , Emetina/análogos & derivados , Subunidade alfa do Fator 1 Induzível por Hipóxia/antagonistas & inibidores , Linhagem Celular Tumoral , Emetina/isolamento & purificação , Emetina/farmacologia , Humanos , Raízes de Plantas/química , Relação Estrutura-AtividadeRESUMO
Tubulin-binding agents play a pivotal role in current cancer therapy and there are many efforts in pre-clinical and clinical development of known and novel cytotoxic agents ongoing. In this article a known class, epothilones, as well as a novel class, tubulysins, are presented.
Assuntos
Antineoplásicos/isolamento & purificação , Antineoplásicos/farmacologia , Emetina/análogos & derivados , Emetina/isolamento & purificação , Emetina/farmacologia , Myxococcales/química , Tubulina (Proteína)/análogos & derivados , Tubulina (Proteína)/isolamento & purificação , Antineoplásicos/síntese química , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Emetina/síntese química , Emetina/química , Indicadores e Reagentes , Modelos Moleculares , Conformação Molecular , Tubulina (Proteína)/síntese química , Tubulina (Proteína)/química , Tubulina (Proteína)/farmacologiaRESUMO
Emetine dithiocarbamate metal complexes, which were prepared from emetine, carbon disulfide, and metal(II), indicated large chemiluminescence intensities on tris(2,2'-bipyridine)-ruthenium(II) chemiluminescence. Capillary electrophoresis with chemiluminescence detection was developed for analyzing emetine and the metal complexes. After the optimization of various analytical conditions, the mixture of the Cu(II), Ni(II), and Co(II) complexes as a model sample was injected into the capillary electrophoresis system with chemiluminescence detection. They were successfully separated and detected with a detection limit of 50 nM.
Assuntos
2,2'-Dipiridil/análogos & derivados , 2,2'-Dipiridil/análise , Eletroforese Capilar/métodos , Emetina/isolamento & purificação , Complexos de Coordenação , Emetina/análise , Medições LuminescentesRESUMO
From the antitumor-bioactive sap of Pogonopus speciosus, tubulosine [1] was isolated, by activity-directed fractionation using the brine shrimp lethality test, as the major antitumor constituent. 1H-nmr assignments, obtained from HETCOR and COSY, and X-ray crystallographic results are reported for the first time. Psychotrine [2] was also isolated, and its spectral data are also reported.
