Recovery and antioxidant activity of extracts from leptocarpha rivularis by supercritical carbon dioxide extraction

We studied the effects of temperature (40, 50, and 60 degrees C) and pressure (9,12, and 15 MPa) on the recovery and antioxidant activity of the essential oil from Leptocarpha rivularis leaves by supercritical CO2 using a 32 factorial design. Experimental data were analyzed with the response surface methodology. Extraction yield varied from 23.5 to 42.6 g/kg d.s., and the resultant antioxidant activity (DPPH assay) varied from 0.60 to 1.84 mmol TE/kg. The highest extraction yield and antioxidant activity in the supercritical extract at 40 degrees C and 15 MPa, respectively 2.5 and 5 times higher than in hydrodistilled extract. However, the extraction yield and antioxidant activity of a hydroethanolic extract were higher than those of supercritical extracts. Three target terpenoids of L, rivularis (alpha-thujone, beta-caryophyllene and caryophyllene oxide) were quantified in the supercritical extract using GC/FID; they were not detected in the hydroethanolic extract. (C) 2015 Elsevier B.V. All rights reserved.