RESUMO
Quercetin and its derivatives are important flavonols that show diverse biological activity, such as antioxidant, anticarcinogenic, anti-inflammatory, and antiviral activities. Adding different substituents to quercetin may change the biochemical activity and bioavailability of molecules, when compared to the aglycone. Here, we have synthesised two novel derivatives of quercetin, quercetin-3-O-ß-d-glucopyranosyl, 4''-O-d-galactopyranosyl 3'''-O-α-N-acetyl neuraminic acid i.e. 3'-sialyllactosyl quercetin (3'SL-Q) and quercetin-3-O-ß-d-glucopyranosyl, 4''-O-ß-d-galactopyranosyl 6'''-O-α-N-acetyl neuraminic acid i.e. 6'-sialyllactosyl quercetin (6'SL-Q) with the use of glycosyltransferases and sialyltransferases enzymes. These derivatives of quercetin were characterised by high-resolution quadrupole-time-of-flight electrospray ionisation mass spectrometry (HR-QTOF-ESI/MS) and 1H and 13C nuclear magnetic resonance (NMR) analyses.
Assuntos
Antineoplásicos Fitogênicos/química , Lactose/análogos & derivados , Quercetina/análogos & derivados , Quercetina/química , Ácidos Siálicos/química , Antineoplásicos Fitogênicos/síntese química , Antineoplásicos Fitogênicos/farmacologia , Técnicas de Química Sintética , Ensaios de Seleção de Medicamentos Antitumorais , Glicosiltransferases/química , Glicosiltransferases/metabolismo , Células Hep G2 , Humanos , Lactose/síntese química , Lactose/química , Lactose/farmacologia , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Quercetina/síntese química , Quercetina/farmacologia , Ácidos Siálicos/síntese química , Ácidos Siálicos/farmacologia , Sialiltransferases/química , Sialiltransferases/metabolismo , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
Two types of tin dioxide (SnO2) films were grown by mist chemical vapor deposition (Mist-CVD), and their electrical properties were studied. A tetragonal phase is obtained when methanol is used as the solvent, while an orthorhombic structure is formed with acetone. The two phases of SnO2 exhibit different electrical properties. Tetragonal SnO2 behaves as a semiconductor, and thin-film transistors (TFTs) incorporating this material as the active layer exhibit n-type characteristics with typical field-effect mobility (µ(FE)) values of approximately 3-4 cm(2)/(V s). On the other hand, orthorhombic SnO2 is found to behave as a metal-like transparent conductive oxide. Density functional theory calculations reveal that orthorhombic SnO2 is more stable under oxygen-rich conditions, which correlates well with the experimentally observed solvent effects. The present study paves the way for the controlled synthesis of functional materials by atmospheric pressure growth techniques.
