Total Phenolic Content and Antioxidant Activity in Leaves and Drupes of Ten Olive Varieties

Abstract

Leaves and drupes of the olive varieties "Koroneiki", "Lianolia Kerkyras", "Mastoidis", "Arbequina", "Adramytini", "Megaritiki", "Gaidourelia", "Kalamata", "Konservolia" and "Chalkidiki", were collected at different seasons during the years 2008 & 2009 and investigated for their total phenolic content and antioxidant activity. Total phenolic content and antioxidant activity were determined according to Folin-Ciocalteau and DPPH assays, respectively. Different varieties presented differences in the total phenolic content and total antioxidant activity per tissue. For both years, most varieties showed higher total phenolic content in new season leaves than in green and black drupes. New season leaves on April showed the highest total phenolic content than the leaves of September and December of the same year, with a few exceptions. There was a positive correlation between the antioxidant activity and the total phenolic content. Highest phenolic content was accompanied by a lower IC₅₀ value and as a result higher antioxidant activity.