Estudios científicos
Hopeaphenol: the first resveratrol tetramer in wines from North Africa
Abstract:
Grapes and wines are now known to constitute a rich source of phenolics such as stilbenes and flavonoids. These compounds have been shown to have cancer chemopreventive activity and potential beneficial effects on cardiovascular diseases thanks to their antioxidant and antiplatelet properties. However, because little is known about African wines and their phenolic compositions, we investigated wine samples from North Africa. A three-step method was used for the fractionation of the Merlot variety wine: column chromatography followed by centrifugal partition chromatography and reversed-phase semipreparative high-performance liquid chromatography (HPLC). Six polyphenolic compounds of the Merlot variety (from Algeria) were isolated and identified by NMR spectroscopy, five of which are known (trans-resveratrol, trans-piceid, trans-epsilon-viniferin, pallidol, and astilbin) and one that is reported for the first time in wine, (+)-hopeaphenol, a stilbene tetramer. Furthermore, these molecules were quantified in 10 commercial wines from North Africa by means of an analytical HPLC system coupled with diode array detection. Differences in concentrations were found ranging in mg/L from 4.6 to 45 (trans-piceid), 0.66 to 3.45 (trans-resveratrol), 0.2 to 1.2 (trans-epsilon-viniferin), 0.2 to 9.2 (pallidol), 0.3 to 3.8 (hopeaphenol), and 10.8 to 24.22 (astilbin). Such a high level of pallidol and astilbin has never been recorded in wine. North African wines may contribute to a significant proportion of dietary intake of stilbene and astilbin, which may have health benefits.
Comentarios divulgativos:
Las Uvas y vinos ahora se sabe que constituyen una rica fuente de compuestos fenólicos como estilbenos y flavonoides. Estos compuestos han demostrado tener actividad frente al cáncer y potenciales efectos beneficiosos en enfermedades cardiovasculares gracias a sus propiedades antioxidantes y antiagregantes plaquetarios. Sin embargo, como se sabe poco sobre los vinos de África y su composición fenólica, se han investigado muestras de vino del norte de África. Un método de tres pasos se utiliza para el fraccionamiento del vino variedad Merlot: se usa la cromatografía de columna seguido de cromatografía de partición en fase reversa y cromatografía líquida (HPLC). Seis compuestos polifenólicos de la variedad Merlot (de Argelia) se aislaron e identificaron por espectroscopía de RMN, cinco de los cuales son conocidos (trans-resveratrol, trans-piceid, trans-epsilon-viniferin, pallidol y astilbin) y uno que se reporta por primera vez en el vino, ()-hopeaphenol, un tetrámero. Además, estas moléculas fueron cuantificadas en 10 vinos comerciales del norte de África por medio de un sistema de análisis HPLC. Los vinos del Norte de África pueden contribuir a una proporción significativa de la ingesta alimentaria de los estilbenos y astilbin, que puede tener beneficios para la salud.
