Processing cherries (Prunus avium) using supercritical fluid technology. Part 1: Recovery of extract fractions rich in bioactive compounds

In the recent years many studies on cherries revealed that they are rich sources of bioactive compounds with beneficial biological activity.In this work, fractioned high pressure extractions were performed on a traditional sweet cherry variety from Portugal (“Saco”) in order to recover natural ingredients with bioactivity. The methodology employed comprised a first step with supercritical CO₂ followed by a second step where different mixtures of CO₂ and ethanol (10-100%, v/v) were tested. All extractions were performed at 50 °C and 25 MPa during 1 plus 1.5 h and the resulting extracts were then characterized in terms of global yield, phenolic content, antioxidant activity and screened for the presence of perillyl alcohol, a powerful anticancer compound. Moreover, cell-based assays were also performed as preliminary evaluation of potential antiproliferative activity of the cherry extracts.In the first step, lower yields were obtained and the extracts presented lower phenolic and antioxidant activity than those recovered in the second step. The extract obtained with CO₂:EtOH (90:10, v/v) exhibited the highest antioxidant activity (181.4 ± 23.7 μmol TEAC/g) and was the most effective in inhibiting the growth of human colon cancer cells (ED50_96h = 0.20 ± 0.02 mg/mL). Perillyl alcohol was pointed to be one of the major responsible for antiproliferative properties of cherry extracts as it was detected in the most promising products, and polyphenols, in particular sakuranetin and sakuranin, seemed to be the major contributors of the antioxidant capacity.