Determination of phenolic compounds of biological interest in some Italian Red Wines by HPLC-DAD

As there is a continuous interest to characterise wines of different origin with regard to their antioxidant activity, we have examinated the phenolic content of some Aglianico red wines by gradient elution reversed-phase HPLC and UV diode array detection (DAD). The potential health benefits of red wine might partly be due to the presence of natural flavonoids, such as catechin, epicatechin, cis-resveratrol, quercetin and myricetin. Catechin and epicatechin were quantified by direct sample injection, while the determination of free cis-resveratrol, trans-resveratrol, myricetin and quercetin was preceded by a concentration step on SPE C18 cartridges. The quantitative analysis was accomplished by standard addition using beta-naphthol as internal standard. The phenolic content detected in this study in Aglianico red wines ranges from 49.7 to 68.6 mg/L. As expected the level of cis-resveratrol was lower than that of trans-resveratrol, with average values of 0.27 and 0.86 mg/L, respectively. The presence of hydroxytyrosol and myricetin in some Aglianico wines was ascertained by on-line spectral comparison.