Title
Green solvents based on choline chloride for the extraction of spruce bark (Picea abies)
Authors
A. SKULCOVA Z. HASCICOVA L. HRDLICKA J. SIMA and M. JABLONSKY

Received February 22, 2017
Published Volume 52 Issue 3-4 March-April
Keywords extraction, spruce bark, deep eutectic solvent, choline chloride, antioxidant activity, total phenolic content

Abstract
Spruce bark is a rich source of extractives, such as condensed tannins, suberin, resin acids and terpenes. Deep eutectic solvents (DESs), a new type of green solvents, were used in this study for obtaining a spruce bark extract with valuable properties. Choline chloride-based eutectic solvents with carboxylic acids and glycerol were used as extractants. The extractions were performed for 1 h at 60 °C under continuous stirring. The antioxidant activities were evaluated using an antioxidant system with 2,2-diphenyl-1-picrylhydrazyl (DPPH). The content of the total phenolics in the extracts was determined spectrometrically according to the Folin-Ciocalteu procedure and expressed as gallic acid equivalent (GAE). The results indicated promising possibilities for the development and usage of eutectic solvents for bark pretreatment. All the tested extracts showed phenolic contents that ranged from 41 to 463 mg GAE/100 g extract. No correlation between the total phenolic content and antioxidant activity was observed. This study demonstrated that DESs are environmentally suitable solvents for extracting phenolic compounds from spruce bark.