Extraction of bilberry (Vaccinium myrtillus) antioxidants using supercritical/subcritical CO2 and ethanol as co-solvent

Abstract Anthocyanins and other phenolic compounds of bilberry ( Vaccinium myrtillus ) are known for their antioxidant properties. Supercritical (SC) and subcritical (SubC) CO 2 extractions have been used to improve extraction and selectivity of plant bioactive compounds. Bilberry was extracted by SC CO 2 followed by SubC CO 2 with 10% v/v ethanol as co-solvent. Total phenolic compounds, anthocyanins and proanthocyanidins were quantified and chemically characterized by HPLC-DAD-ESI-MS/MS. Antioxidant activity was tested by reducing power assay, free radical scavenging activity (DPPH) and ABTS radical cation assay. SubC CO 2 selectively extracted cyanidin-3- O -glucoside and cyanidin-3- O -arabinoside. Delphinidin-3- O -glucoside, ellagic acid pentoside, feruloyl hexoside and several quercetin glycosides were also extracted. SubC CO 2 extracts showed a high antioxidant activity [DPPH IC 50  = 102.66 (±2.64); ABTS IC 50  = 8.49 (±0.41) and reducing power activity IC 50  = 10.30 (±0.10)]. SubC-CO 2 extraction of bilberry is an efficient method to recover selectively compounds with a high antioxidant activity and a high potential for pharmacological applications.