Recovery of antioxidants from boldo (Peumus boldus M.) by conventional and supercritical CO2 extraction

Abstract Boldo ( Peumus boldus M.) is a native plant from Chile that has been used is traditional medicine to treat digestive and/or hepatobiliary disorders. An attempt was made in this work to extract antioxidant compounds from boldo using conventional solvents and supercritical carbon dioxide (SCCO 2 ). Yield of soluble solids (SS), boldine, and compounds with antioxidant activity varied depending on part plant, solvent and extraction conditions. Following 24 h extraction, the highest yield was 33.4% (w/w, dry basis) of SS with 70:30 ethanol/water (v/v) mixture at 70 °C. Yield of alcoholic extractions increased as the temperature was raised from 20 to 70 °C, but the total antioxidant activity (free radical DPPH method) was maximal in boldo leaf extracts with aqueous ethanol at 50 °C (1648 TEAC/g dry leaf). Boldine concentration was maximal (12%) in boldo bark extracted with acidulated water, and decreased with extraction time when methanol or ethanol/water mixtures were used. No boldine was detected in boldo leaf extracts. The contribution of boldine to the antioxidant activity of boldo extracts was low, specially when using aqueous ethanol as solvent, and/or boldo leaf instead of boldo bark as substrate. Yield of SCCO 2 extraction was ≈3% SS. Only non-polar compounds with limited antioxidant activity (0.08 TEAC/g extract) were extracted by SCCO 2 .