Supercritical Fluid Extraction of the Lichen Thallus Hypogymnia physodes

Abstract

The process of supercritical fluid extraction (SCFE) of the thallus of the lichen species Hypogymnia physodes with carbon dioxide in the presence of acetone as a cosolvent is studied. The extraction conditions (temperature, pressure, and duration) on the yields of the extract (EX), phenolic compounds, including low molecular weight phenols (LPs), atranorin (AT), and flavonoids (FVs) are assessed. It is shown that the main amount of extractives (up to 90%) is extracted within 40 min of extraction. The EX yield reaches 156.5 mg/g with a phenolic compound (PC) content of up to 87.3%. The obtained EXs have high antiradical activity (ARA) (up to 225 μmol Trolox-equiv/g). A positive correlation is established between the ARA of the EXs and the content of PCs in them, including AT. The antibacterial activity of the EXs against the gram-positive (Bacillus subtilis) and gram-negative (Escherichia coli, Proteus mirabilis) strains of microorganisms is revealed.