Supercritical extraction with carbon dioxide and co-solvent from Leptocarpha rivularis

Abstract The aim of this work was to investigate the effect of temperature (40―60 °C), pressure (10―20 MPa) and co-solvent concentration (0―2 wt.%) on extraction yield from L. rivularis leaves using ethanol-modified supercritical carbon dioxide. Extraction assays were carried out in a Process Development Unit using a Box-Behnken design. Extraction yield ranged from 14.7 to 53.1 g/kg dry substrate, with the highest value being achieved at 60 °C, 20 MPa and 2 wt.%. The pressure and the co-solvent concentration had a significant effect on extract recovery. To complement the analysis, recognized bioactive compounds, such as the flavonoids quercetin, kaempferol and resveratrol and the terpenes α-thujone, β-caryophyllene and caryophyllene oxide were quantified in the selected extract. Antioxidant activity and the inhibition of key enzymes linked to diabetes mellitus (α-amylase and α-glucosidase) were exhibited by the extract. These results demonstrate the potential benefit of L. rivularis extract for human health.