Phenolic profiles, antioxidant activity and minerals in leaves of different grapevine varieties grown in Serbia

This research was designed to determine phenolics content, radical scavenging activity and mineral composition of 22 grapevine leaves of diverse varietal origin. Samples were collected from two vineyards located in Central Serbia (Belgrade vineyard area) and Eastern Serbia (Mlava vineyard area). Leaf extracts were characterized mostly with phenolics acids, flavonols and flavan-3-ols. Ellagic acid and rutin were the most abundant components, found in the concentration up to 770 mg/kg and 450 mg/kg of dry weight, respectively. Total phenolic content was in the range from 27.5 to 76.0 g GAE/kg of dry weight while the radical scavenging activity ranged from 0.429 to 0.867 mmol TE/kg of dry weight. The most common element in all samples was IC (content ranging from 2.30 g/kg to 6.77 g/kg of dry weight), followed by Ca, Na, and B. A variation in the chemical composition was shown to be convenient way to differentiate among the grape leaves of diverse varietal origin. Clear separation was demonstrated between objects of different geographical origin by Principal Component Analysis. Serbian variety 'Petra', an interspecies hybrid with atypical composition, was detected as an outlier in comparison to other samples