Solubility of boldo leaf antioxidant components (Boldine) in high-pressure carbon dioxide

Abstract

This work contributes to the development of an enrichment process for antioxidant compounds in aqueous alcoholic extracts of boldo (Peumus boldus M.) leaves by using high-pressure CO2 as the solvent. Specifically we measured the high-pressure solubility (y(2), molar fraction) of a selected bioactive compound in boldo leaves (boldine) in CO, as a function of system temperature (298 K <= T <= 333 K) and pressure (8 MPa <= P <= 40 MPa). Experimental data was correlated by using a density-based model which is valid for solvent densities > 607 kg/m(3). Predicted solubility values are low (4 x 10(-7) <= y(2) <= 6 x 10(-5)) but comparable with those of nitrogen-containing organic compounds with similar molecular weight (327.4 Da) and solubility parameter (28.3 MPa (0.5) at 313 K) as boldine. (c) 2005 Elsevier B.V. All rights reserved.