RESUMO
As part of our program to develop potential imaging agents for ascorbate bioactivity in the brain, 5-O-(4'-iodobenzyl)-L-ascorbic acid was prepared through a seven-step sequence which involved C5-O-alkylation with p-iodobenzyl bromide in the presence of Ag2O and CaSO4 as the key step, starting from L-ascorbic acid. The scavenging activity of the p-iodobenzylated analog against 2,2-diphenyl-1-picrylhyrazyl (DPPH) radical was almost the same as that of L-ascorbic acid itself.
Assuntos
Ácido Ascórbico/análogos & derivados , Sequestradores de Radicais Livres/síntese química , Sequestradores de Radicais Livres/farmacologia , Alquilação , Ácido Ascórbico/síntese química , Ácido Ascórbico/farmacologia , Compostos de Bifenilo , Diagnóstico por Imagem , Indicadores e Reagentes , Espectroscopia de Ressonância Magnética , Picratos/química , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas de Bombardeamento Rápido de Átomos , Espectrofotometria InfravermelhoRESUMO
The relationship between in vivo biodistribution of 6-deoxy-6-[18F]fluoro-L-ascorbic acid (18F-DFA) and the content of tissue glutathione (GSH) was investigated in Wistar male rats. Following intravenous administration of 18F-DFA, the accumulation of radioactivity in most tissues, including the adrenal glands, liver and brain, was significantly reduced together with a decrease in the content of GSH by preloading of diethyl maleate (DEM) which depletes cellular GSH. Similar decreased uptake was also observed in the distribution of L-[1-14C]ascorbic acid (14C-AA) after DEM treatment. The possible biological mechanisms, including competition with endogenous AA and ascorbate recycling, that modulate the uptake and accumulation into tissues of 18F-DFA and 14C-AA in GSH-deficient rats are discussed.