RESUMO
Feeding a high-cholesterol diet with a water-soluble peanut skin polyphenol fraction to rats reduced their plasma cholesterol level, with an increase in fecal cholesterol excretion. The hypocholesterolemic effect was greater with the lower-molecular-weight rather than higher-molecular-weight polyphenol fraction. This effect was possibly due to some oligomeric polyphenols which reduced the solubility of dietary cholesterol in intestinal bile acid-emulsified micelles.
Assuntos
Anticolesterolemiantes/uso terapêutico , Arachis/química , Dieta Hiperlipídica , Frutas/química , Polifenóis/uso terapêutico , Animais , Anticolesterolemiantes/administração & dosagem , Anticolesterolemiantes/isolamento & purificação , Ácidos e Sais Biliares/metabolismo , Colesterol na Dieta/administração & dosagem , Colesterol na Dieta/sangue , Fezes/química , Mucosa Intestinal/metabolismo , Fígado/metabolismo , Masculino , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Polifenóis/administração & dosagem , Polifenóis/isolamento & purificação , Ratos , SolubilidadeRESUMO
Peanut skin contains large amounts of polyphenols having antiallergic effects. We found that a peanut-skin extract (PSE) inhibits the degranulation induced by antigen stimulation of rat basophilic leukemia (RBL-2H3) cells. A low-molecular-weight fraction from PSE, PSEL, also had inhibitory activity against allergic degranulation. A main polyphenol in PSEL was purified by gel chromatography and fractionated by YMC-gel ODS-AQ 120S50 column. Electrospray ionization mass spectrometry (ESI-MS) analysis of the purified polyphenol gave m/z 599 [M+Na]âº. Based on the results of ¹H-NMR, ¹³C-NMR spectra, and optical rotation analysis, the polyphenol was identified as procyanidin A1. It inhibited the degranulation caused by antigen stimulation at the IC50 of 20.3 µM. Phorbol-12-myristate-13-acetate (PMA) and 2,5,-di(tert-butyl)-1,4-hydroquinone (DTBHQ)-induced processes of degranulation were also inhibited by procyanidin A1. These results indicate that peanut-skin procyanidin A1 inhibits degranulation downstream of protein kinase C activation or Ca²âº influx from an internal store in RBL-2H3 cells.