Improved extraction of bioactive compounds from Monteverdia aquifolia leaves by pressurized-liquid and ultrasound-assisted extraction: Yield and chemical composition

Monteverdia aquifolia leaves extracts was obtained using pressurized-liquid extraction (PLE) and ultrasound-assisted extraction (UAE), evaluating, when pertinent, temperature, solvent, solvent/biomass ratio, and sonication amplitude (%), comparing to the conventional Soxhlet extraction (SOX) concerning yield (wt%), total phenolic content (TPC), antioxidant activity (AA), and chemical composition. The highest yield was 8.3% obtained in SOX with ethanol (360 min and +/- 78 degrees C). With the same solvent, UAE reached 6.6% (30 min, 50 degrees C, amplitude 80%, and solvent/biomass ratio 20 mL g(-1)), and the PLE reached 5.3% (25 min and 60 degrees C), corresponding to 79.2% and 63.7% of the SOX yield, respectively. However, UAE and PLE consumed a smaller volume of solvent, operated for a shorter time, and provided improved extracts, with higher TPC and AA, compared to conventional extraction. The extracts proved to be a good source of bioactive compounds, such as Vitamin E, Friedelin, Friedelanol, and Squalene.