RESUMO
In this study, we present the isolation and characterization of the structure of six gallotannins (1-6), three ellagitannins (7-9), a neolignan glucoside (10), and three related polyphenolic compounds (gallic acid, 11 and 12) from Trapa bispinosa Roxb. pericarp extract (TBE). Among the isolates, the structure of compound 10 possessing a previously unclear absolute configuration was unambiguously determined through nuclear magnetic resonance and circular dichroism analyses. The α-glucosidase activity and glycation inhibitory effects of the isolates were evaluated. Decarboxylated rugosin A (8) showed an α-glucosidase inhibitory activity, while hydrolyzable tannins revealed stronger antiglycation activity than that of the positive control. Furthermore, the identification and quantification of the TBE polyphenols were investigated by high-performance liquid chromatography coupled to ultraviolet detection and electrospray ionization mass spectrometry analysis, indicating the predominance of gallic acid, ellagic acid, and galloyl glucoses showing marked antiglycation properties. These findings suggest that there is a potential food industry application of polyphenols in TBE as a functional food with antidiabetic and antiglycation activities.
Assuntos
Inibidores de Glicosídeo Hidrolases/isolamento & purificação , Lythraceae/química , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Dicroísmo Circular , Ácido Elágico/isolamento & purificação , Indústria Alimentícia , Alimento Funcional/análise , Ácido Gálico/análogos & derivados , Ácido Gálico/isolamento & purificação , Glucosídeos/isolamento & purificação , Taninos Hidrolisáveis/isolamento & purificação , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Extratos Vegetais/química , Polifenóis/química , Polifenóis/isolamento & purificação , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
We investigated the inhibitory effects of several plant extracts on advanced glycation end-products (AGEs) formation. Among tested samples, the flower extract of Magnolia coco showed significant inhibition of AGE formation. We isolated and characterized procyanidin oligomer and four other compounds from the flowers, and evaluated their inhibitory effects on AGE formation and the AGE-derived crosslink-cleaving activity of the isolated compounds.
Assuntos
Biflavonoides/química , Catequina/química , Flores/química , Produtos Finais de Glicação Avançada/antagonistas & inibidores , Magnolia/química , Polifenóis/química , Proantocianidinas/química , Biflavonoides/isolamento & purificação , Catequina/isolamento & purificação , Frutose/química , Glucose/química , Glicosilação , Humanos , Extratos Vegetais/química , Polifenóis/isolamento & purificação , Proantocianidinas/isolamento & purificação , Albumina Sérica/químicaRESUMO
Polygonum cuspidatum has been broadly utilized as a herbal medicine in Asia, but the outline of the polyphenol compounds in the plant has not been characterized well. In the present study, the major polyphenolic components were isolated from the roots of P. cuspidatum, and identified as resveratrol and its glucosides, resveratroloside and polydatin. On the other hand, chlorogenic acid was found to be one of the polyphenolic components in the leaves and stems of the plant. Next, we elucidated that resveratrol derivatives and chlorogenic acid exhibit α-glucosidase inhibitory activities, and resveratroloside exhibits the same inhibitory activity as quercetin does. Furthermore, DPPH radical scavenging activities of antioxidants including resveratrol derivatives and chlorogenic acid derivatives were examined by initial rate analyses of their reactions. Subsequently, it was revealed that resveratrol derivatives have slow-acting effects on the radical scavenging activity and that chlorogenic acid derivatives exhibit very fast-acting effects.