RESUMO
An aqueous ethanol extract of Pyrola rotundifolia L. induced AMP-activated protein kinase (AMPK) phosphorylation in C2C12 myotubes. The bioassay-guided fractionation of the extract led to the isolation a 2-methyl-7-hydroxymethyl-1,4-naphthoquinone, or a 7'-hydroxy-chimaphilin, which showed concentration-dependent AMPK phosphorylation activity at 2.5-20 µg/ml. At a concentration of 10 µg/ml (50 µM), an approximately four-fold increase in the AMPKα(Thr¹7²) phosphorylation level was observed. The stimulatory effect of naphthoquinone on AMPK activity was comparable to that of known compounds found in natural sources that activate the AMPK signaling pathway.
Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Ativadores de Enzimas/farmacologia , Fibras Musculares Esqueléticas/efeitos dos fármacos , Naftoquinonas/farmacologia , Extratos Vegetais/farmacologia , Pyrola/química , Animais , Linhagem Celular , Relação Dose-Resposta a Droga , Ativadores de Enzimas/isolamento & purificação , Camundongos , Estrutura Molecular , Fibras Musculares Esqueléticas/metabolismo , Naftoquinonas/isolamento & purificação , Fosforilação , Extratos Vegetais/químicaRESUMO
An aqueous ethanol extract of Bergenia crassifolia rhizomes strongly inhibited human pancreatic lipase activity and increased scavenging of DPPH free radicals in vitro. Chromatographic separation of this extract led to isolation of the hydrolysable tannins (+)-catechin 3,5-di-O-gallate (1) and (+)-catechin 3-O-gallate (2). This is the first report of the isolation of compound 1 from plant material. This compound strongly inhibited human pancreatic lipase (with an IC(50) value of 0.42 µg/ml) and exhibited a remarkable free radical-scavenging ability (with an SC(50) value of 1.04 µg/ml). The chemical structures of 1 and 2 were elucidated using MS, NMR and chemical approaches.
