Optimization of polyphenols extraction process with antioxidant properties from wild Vaccinium myrtillus L. (bilberry) and Vaccinium vitis-idaea L. (lingonberry) leaves

The aim of the current study was to optimize the extraction condition of polyphenol compounds with antioxidant properties from leaves of natural grown Vaccinium myrtillus L and Vaccinium vitis-idaea L. The extractions were carried out in ultrasonic bath at 40 oC for 20 minutes with different solvents (water, 20 % ethanol, 40 % ethanol, 60 % ethanol, 80 % ethanol and 96 % ethanol) and different hydro module of samples and solvents used (1:50, 1:100 and 1:200). The highest total phenol content in the leaves of V. myrtillus L. and V. vitis-idaea L. was found when 40% ethanol extract was used (90.50 ± 0.05 mg GAE/g DW and 96.68 ± 0.05 mg GAE/g DW, respectively). The highest total flavonoid content of the leaves of both species was obtained with 80 % ethanol as extraction solvent. The highest level of total proanthocyanidins were in the 60 % ethanol extract of V. myrtillus L. and in the 80 % ethanol extract of V. vitis-idaea L (13.12 ± 0.11 mg LE/g DW and 24.22 ± 0.21 mg LE/g DW, respectively). The highest ability to scavenge DPPH radicals possessed the 40 % ethanol extracts from the leaves of both species (693.99 ± 4.05 mM TE/g DW for V. myrtillus L. and 1083.18 ± 8.48 mM TE/g DW for V. vitis-idaea L). Data analysis showed that the maximal amount of polyphenols was extracted at a hydro-module of 1: 100. HPLC analysis revealed that the dominant phenolic acid in the leaves of V. myrtillus L was chlorogenic acid (13.45 mg/g DW), while ferulic acid (49.48 mg/g DW) was present at the highest concentration in the leaves of V. vitis-idaea L.