Studies on the phenolic content of red senescent grapevine leaves - a sustainable source of bioactive compounds

Abstract

n order to identify new sustainable sources of bioactive compounds for food, pharmaceutical and cosmetic industries, anthocyanin,proanthocyanidin and total phenolic contents of red senescent leaves of 47 grapevine cultivars and chromatic parameters of their alcoholic extracts were evaluated. Leaves were picked between two to eight weeks after grape harvest, the remaining chlorophyll and carotenoid amounts being also quantified. Red grapevine leaves showed high antioxidant activity (% scavenged DPPH), proportionally correlated with the concentration of anthocyanins and total phenolic compounds. Chlorophyll and carotenoid content of red leaves was low, without exceeding 1.56mg/g and 0.92mg/g dry weight, respectively. High amounts of antioxidant anthocyanins, proanthocyanidins and total phenolic compounds, as well as the chromatic diversity of the obtained extracts, justify the use ofsenescent red grapevine leaves as raw material in the production of valuable dietary supplements.