Supercritical carbon dioxide extraction of antioxidants from rosemary (Rosmarinus officinalis L.) and sage (Salvia officinalis L.)

Abstract

The aim of the present study was to isolate and characterize antioxidant extracts obtained from dried leaves of rosemary (Rosmarinus officinalis L.) and sage (Salvia officinalis L.), originating from the southern Balkan Region. The antioxidant fraction was isolated from the plant material by supercritical carbon dioxide (SC-CO2) fractional extraction under a pressure of 30 MPa and at temperatures of 40 and 100?C. In the present study, kinetic data and yields of antioxidant extracts obtained from dried leaves of rosemary and sage under different conditions were determined. Electron spin resonance (ESR) spectroscopy assay on the ability of the extracts to scavenge stable 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals and reactive hydroxyl radicals during the Fenton reaction trapped by 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) showed that the investigated extracts had antioxidant activity comparable to that of butylated hydroxyanisole (BHA) and commercial rosemary extract. The antioxidant fractions isolated at the higher temperature had higher antioxidant activities. A tentative analysis of the chemical composition of the antioxidant fractions obtained at the higher temperature was accomplished by LC-DAD and LC-MS analytical methods. Abietane-type diterpenoids, flavonoids and fatty acids were identified in the SC-CO2 extract of rosemary and sage.