RESUMO
The plant, Cynomorium songaricum Rupr., is used as a traditional medicine in China and Mongolia. In the present study, two new water-soluble polysaccharides isolated from C. songaricum Rupr. were purified by successive Sephadex G-75 and G-50 column chromatographies and then characterized by high resolution NMR and IR spectroscopies. The molecular weights of two polysaccharides were determined by an aqueous GPC to be [Formula: see text] = 3.7 × 10(4) and 1.0 × 10(4), respectively. In addition, it was found that the polysaccharide with the larger molecular weight was an acidic polysaccharide. It was found that the iodine-starch reaction of both isolated polysaccharides was negative and the methylation analysis gave 2, 4, 6-tri-O-methyl alditol acetate as a main product. NMR and IR measurements and sugar analysis revealed that both polysaccharides had a (1 â 3)-α-d-glucopyranosidic main chain with a small number of branches. After sulfation, the sulfated C. songaricum Rupr. polysaccharides were found to have a potent inhibitory effect on HIV infection of MT-4 cells at a 50% effective concentration of 0.3-0.4 µg/ml, a concentration that has almost the same high activity as standard dextran and curdlan sulfates, EC50 = 0.35 and 0.14 µg/ml, respectively. The 50% cytotoxic concentration was low, CC50>1000 µg/ml. In addition, the interaction between the sulfated polysaccharides and poly-l-lysine as a model protein compound was investigated by a surface plasmon resonance to reveal the anti-HIV mechanism.
Assuntos
Fármacos Anti-HIV/isolamento & purificação , Fármacos Anti-HIV/farmacologia , Cynomorium/química , Polissacarídeos/isolamento & purificação , Polissacarídeos/farmacologia , Fármacos Anti-HIV/química , China , Dextranos , Infecções por HIV/tratamento farmacológico , Humanos , Medicina Tradicional Chinesa , Medicina Tradicional da Mongólia , Modelos Biológicos , Estrutura Molecular , Peso Molecular , Ressonância Magnética Nuclear Biomolecular , Caules de Planta/química , Polilisina/química , Polissacarídeos/química , Solubilidade , Espectrofotometria Infravermelho , ÁguaRESUMO
A novel indirect substitution spectrophotometric methodology using porphyrin is developed for the determination of some metals that do not react with porphyrin directly. The methodology is concerned with a multistep reaction system, which consists of 3 complexation reactions that occur in a sequence of EDTA with metal, EDTA with Cu(II) and porphyrin with Cu(II). The complexation reaction of Cu(II) with a cationic porphyrin, meso-tetrakis (4-N-trimethylaminophenyl)-porphine (ttmapp), which has a high molar absorptivity about 5 x 10(5)l mol(-1)cm(-1), serves for spectrophotometric detection. This methodology was verified through individual determinations of 14 species of lanthanides following a batchwise procedure, which was further developed to an automatic procedure on a HPLC post-column flow injection system for simultaneous analysis of the lanthanides. Compared with the conventional post-column derivatization method using 4-(2-pyridylazo) resorcinol (PAR), the analytical sensitivity was greatly improved in this method and the results also showed good linearity.