Effect of supercritical CO2 modified with ethanol on the extraction yield and antimicrobial activity of bioactive compounds from aerial parts of Berberis microphylla G. Fort

Calafate ( Berberis microphylla G. Forts) is an endemic plant from the Patagonian area of Chile and Argentina, with a high content of bioactive compounds. In this study the effect of ethanol-modified supercritical extraction at temperatures of 40 and 60 °C, pressures of 30 and 35 MPa, and azeotropic ethanol contents in CO 2 of 5 and 10% on the yield of total solids (gravimetric method), alkaloids (spectrophotometric analysis), berberine (HPLC-DAD analysis), phenolics (spectrophotometric analysis), and antimicrobial activity (disc diffusion method) of calafate aerial parts, was evaluated. The yield of total solids increased with extraction temperature, pressure, and the percentage of ethanol in CO 2 . Berberine yield reached a maximum of 0.0211 ± 0.46 g/kg substrate at 60 °C, 35 MPa, and using 10% ethanol. Extraction at 40 °C resulted in a higher phenolic content (1.69 ± 0.02 g GAE/kg substrate) than at 60 °C. Limited antibacterial activity was observed in all obtained extracts with ethanol-modified supercritical CO 2 against Staphylococcus aureus , with no significant difference between treatments. Ethanol-modified CO 2 demonstrated moderate efficiency for extracting bioactive compounds from calafate aerial parts compared with Soxhlet extraction with azeotropic ethanol. • Extraction process shows different effects on phenolic and alkaloid yields of Calafate aerial parts. • Ethanol content in CO 2 increases the total solids yield. • Addition of ethanol does not improve the selectivity of alkaloid extraction. • Antimicrobial activity correlates with alkaloid content in extracts.