Polygala cyparissias oleoresin: Comparing CO2 and classical organic solvent extractions

Composition of plant extracts and process efficiency are mainly defined by the extraction method used. Plant materials are rich source of valuable substances and the Polygala cyparissias, a bush that grows at dune regions in South America, presents important active compounds. Therefore, the present study deals with the assessment of the composition profile of P. cyparissias extracts, from root and from stems and leaves, obtained by CO2 at various conditions of temperature and pressure and by classical organic solvent extractions. Supercritical CO2 was used at temperatures of 20 and 40 °C, pressures varying from 15 to 20 MPa and solvent flow rate from 1.49 to 4.07 ± 0.02 g CO2 min−1. The extracts were analyzed by GC and GC–MS techniques, in order to quantify and identify the components presents at the plant material. Target components found at the P. cyparissias extracts from different plant sources were triterpenes, phytosterols and methyl salicylate, with notorious biological actions. The CO2 extraction yields were up to 0.35% (w/w), comparable to low-pressure extraction yields obtained by n-hexane and dichloromethane. For optimization purpose, experimental data were correlated by mass transfer models, with low deviation between experimental and modeled data.