M. G. L. Hertog, “Flavonols and Flavones in Foods and Their Relation with Cancer and Coronary Heart Disease Risk,” PhD Thesis, Agricultural University Wageningen, the Netherlands, 1994.

has been cited by the following article:

• TITLE: Study on the Antioxidant Activity of Grape Stems (Vitis vinifera). A Preliminary Assessment of Crude Extracts

  AUTHORS: Antonia Llobera

  KEYWORDS: Grape Stem; Antioxidant Activity; Stem Extracts; Polyphenols; Radical Scavenging Activity; DPPH

  JOURNAL NAME: Food and Nutrition Sciences, Vol.3 No.4, April 18, 2012

  ABSTRACT: The antioxidant activity of 80% ethanol and 70% acetone extracts of stems from red and white grapes (Vitis vinifera) used in wine industry were evaluated to determine their feasibility as natural antioxidants. The results showed that all grape stem extracts were rich in total polyphenolic compounds and flavanols and had clear antioxidant activities. The free radical-scavenging capacity of the extracts was determined using the DPPH (2,2-diphenyl-1-picrylhydrazyl) method. The extracts obtained from red grape stem present EC50 values of 0.14 g dm/g DPPH (acetone extract) and 0.20 g dm/g DPPH (ethanol extract) while the extracts obtained from white grape stem present EC50 values of 0.26 g dm/g DPPH (acetone extract) and 0.37 g dm/g DPPH (ethanol extract). There are significant correlations between the total content of polyphenols and the antioxidant activity (R2 = 0.9352) and between the flavanols content and the antioxidant activity (R2 = 0.9404) of the grape stem extracts obtained.