Abstract

This work studied sequential supercritical extraction to obtain extracts from L. rivularis leaves. Extraction assays were carried out in three stages at 40 or 70?, with stage 1: 20 MPa with CO2, stage 2: 40 MPa with CO2, and stage 3: 40 MPa with ethanol-modified CO2 (5% wt.). The total extraction yield was higher at 70 ? (41.77 g/kg d.s.) than at 40?(32.57 g/kg d.s.). The total content of terpenes and flavonoids and the ability of the extracts to inhibit the a-amylase and a-glucosidase enzymes were measured. At 40 C the stage 1 extract had a greater inhibition effect on a-glucosidase and the stage 2 extract a greater inhibition effect on a-amylase. Sequential supercritical extraction was properly modeled using a diffusion model based on Fick's second law, and an effective diffusion coefficient was determined for each stage. Sequential supercritical extraction can be a method to increase the extraction of bioactive compounds.