Supercritical CO2 extraction as a selective method for the obtainment of coumarins from Pterocaulon balansae (Asteraceae)

Aiming to recover fractions enriched with coumarins, the aerial parts of Pterocaulon balansae Chodat (Asteraceae) were subjected to supercritical fluid extraction (SFE) using CO2 as solvent under constant temperature (40 degrees C) and gradual pressure increments (90, 120, 150 and 200 bar). The yields of the coumarins in the extracts were calculated using high-performance liquid chromatography analyses, which allowed the identification of seven coumarins previously reported by our research group. Coumarin 7-((3,3-dimethyloxiran-2-yl) methoxy)-5,6-dimethoxy-2H-chromen-2-one was identified as the major component of all extracts but we also identified considerable amounts of other epoxysubstituted coumarins. The mild conditions provided by the supercritical CO2 extraction (SC-CO2 extraction) may considerably reduce the ring-opening of the epoxy groups in the coumarins from the aerial parts of P. balansae, when compared to the conventional extraction procedures. (C) 2017 Elsevier Ltd. All rights reserved.