RESUMEN
We conducted liquid chromatography-mass spectrometry measurements on hot-water extracts of peel from different varieties of Allium cepa. Some quercetin glycosides were identified as potential α-glucosidase inhibitors by principal component analysis of the liquid chromatography-mass spectrometry data. α-Glucosidase inhibitory activity assays identified quercetin-4'-O-glucoside as an α-glucosidase inhibitor.
Asunto(s)
Inhibidores de Glicósido Hidrolasas/aislamiento & purificación , Extracción Líquido-Líquido/métodos , Cebollas/química , Quercetina/análogos & derivados , alfa-Glucosidasas/química , Cromatografía Liquida , Inhibidores de Glicósido Hidrolasas/química , Calor , Humanos , Espectrometría de Masas , Extractos Vegetales/química , Análisis de Componente Principal , Quercetina/química , Quercetina/aislamiento & purificación , Residuos/análisis , Agua/químicaRESUMEN
Exposure to light may adversely affect the quality of foods. This investigation of how light exposure affects citrus (orange and mandarin blend) juice in polyethylene terephthalate (PET) bottles demonstrated that the isomeric form of a compound in the juice changed during storage. This compound was identified as feruloylputrescine (FP; CAS: 501-13-3; C14H20N2O3) using LC/MS (Q-TOF). LC/MS and NMR measurements showed that the content of the original form, trans-FP, decreased as it isomerized to cis-FP during storage. This phenomenon could be observed in citrus fruit juices containing FP, such orange and grapefruit juices. Therefore, determining the content of these two isomers of FP could be used to indicate the level of light exposure experienced by citrus fruit products.
Asunto(s)
Citrus/química , Ácidos Cumáricos/química , Jugos de Frutas y Vegetales , Luz , Putrescina/análogos & derivados , Isomerismo , Putrescina/químicaRESUMEN
We have previously found that fatty acids can mask the bitterness of certain nitrogenous substances through direct molecular interactions. Using isothermal titration calorimetry, we investigated the interactions between sodium oleate and 22 bitter substances. The hydrochloride salts of quinine, promethazine, and propranolol interacted strongly with fatty acids containing 12 or more carbon atoms. The (1)H NMR spectra of these substances, obtained in the presence of the sodium salts of the fatty acids in dimethyl sulfoxide, revealed the formation of hydrogen bonds between the nitrogen atoms of the bitter substances and the carboxyl groups of the fatty acids. When sodium laurate and the hydrochloride salt of quinine were mixed in water, an equimolar complex formed as insoluble heterogeneous needlelike crystals. These results suggested that fatty acids interact directly with bitter substances through hydrogen bonds and hydrophobic interactions to form insoluble binary complexes that mask bitterness.