Comparison of phenolic compounds and antioxidant potential between selected edible fruits and their leaves

The aim of this study was to determine and compare a polyphenolic profile and antioxidant activity in leaves and fruits of 7 selected species: Malus domestica (2 cultivars), Cydonia oblonga (4 cv.), Chaenomeles japonica (3 cv.), Ribes nigrum (3 cv.), Aronia melanocarpa (1 cv.), Vaccinium macrocarpon (11 cv.) and Vaccinium myrtillus. Polyphenolic profile was determined by LC-MS and UPLC-PDA-FL and antioxidant activity were analysed by ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)) and FRAP (ferric reducing ability of plasma) test. The results showed that the leaves contained significantly higher polyphenol compounds than the fruits. The highest concentration of total polyphenols were characterized by quince leaves (major group: polymeric proanthocyanidins) followed by cranberry > apple > chokeberry > Japanese quince > bilberry > and blackcurrant leaves (major group: flavonols). Also the strongest antioxidant potential was represented for quince leaves: 116.49 and 65.25 mmol trolox equivalents (TE)/100 g of dry matter (dm) in ABTS and FRAP tests, which correlated with the content of polymerized proanthocyanidins and flavonols.