RESUMEN
An activity-guided isolation and purification process was used to identify the DPPH (l,l-diphenyl-2-picrylhydrazyl) radical-scavenging components of Swertia chirayita. A dry, whole plant of S. chirayita was extracted with different solvents and tested for its DPPH radical-scavenging activity. The acetone : water (8 : 2) extract showed the highest total phenolic content (TPC) and DPPH radical-scavenging activity, which was column chromatographed to obtain decussatin, swertianin, bellidifolin, isobellidifolin, amarogentin, swertianolin and mangiferin as active components. Good correlation was observed between TPC and DPPH scavenging activity among the extracts. The unique structure of xanthones, including the catecholic moiety and the completely conjugated system, enables them to be promising antioxidants.
Asunto(s)
Antioxidantes/química , Extractos Vegetales/química , Swertia/química , Xantonas/química , Depuradores de Radicales Libres/químicaRESUMEN
The binding studies of calix[4]pyrroles (1-6) with fluoro, chloro, bromo, iodo and sulphato anions generated from normal-tetrabutylammoniumfluoride, normal-tetrabutylammoniumchloride, normal-tetrabutylammoniumbromide, normal-tetrabutylammoniumiodide, and normal-tetrabutylammoniumsulphate respectively were investigated by electrospray ionization mass spectrometry (ESI-MS) in dichloromethane-acetonitrile in negative ion mode. The efficacy of a particular calix[4]pyrrole to bind with anions was found maximum at low cone voltage of the instrument, at high cone voltage the binding was suppressed due to removal of anion from the cavity of the macrocycles. The binding strength was found inversely proportional to the size of anion for a particular calix[4]pyrrole. The fragmentation pattern of calix[4]pyrrole was observed at higher cone voltage of ESI-MS and was interpreted. The association constants of calix[4]pyrroles and anions obtained from electronic transition studies were in good agreement with that observed from (1)H NMR titration studies.
Asunto(s)
Aniones/metabolismo , Calixarenos/química , Porfirinas/química , Aniones/química , Catálisis , Colorantes Fluorescentes/química , Modelos Biológicos , Espectrometría de Masa por Ionización de Electrospray , Análisis Espectral/métodosRESUMEN
A facile and efficient protocol is reported for the synthesis of calix[4]pyrroles and N-confused calix[4]pyrroles in moderate to excellent yields by reaction of dialkyl or cycloalkyl ketones with pyrrole catalyzed by reusable Amberlyst(TM)-15 under eco-friendly conditions.
Asunto(s)
Ácidos/química , Calixarenos/síntesis química , Cetonas/química , Porfirinas/síntesis química , Pirroles/química , Estirenos/química , Calixarenos/química , Estructura Molecular , Porfirinas/químicaRESUMEN
The biomimetic oxidation of curcumin, a main turmeric pigment with hydrogen peroxide catalyzed by different 5,10,15,20-tetraarylporphyrinatoiron(III) chlorides [TAPFe(III)Cl] in dichloromethane has been studied to give a C-C coupled curcumin dimer in 40-70% yield. The structure of the dimer has been elucidated by (1)H-, (13)C-NMR, IR and FAB-Mass spectroscopic data.
Asunto(s)
Curcumina/química , Peróxido de Hidrógeno/química , Hierro/química , Metaloporfirinas/química , Oxidantes/química , Indicadores y Reactivos , Espectroscopía de Resonancia Magnética , Cloruro de Metileno , Oxidación-Reducción , Solventes , Espectrometría de Masa Bombardeada por Átomos VelocesRESUMEN
The biomimetic reduction of anti-inflammatory drug, nimesulide (1) with sodium borohydride catalyzed by 5,10,15,20-tetraarylporphyrinatoiron(III) chlorides [TAPFe(III)Cl] has been studied in organic solvents under anaerobic and aerobic conditions.