Extraction of Morus alba leaves using supercritical CO2 and ultrasound-assisted solvent: Evaluation of β-sitosterol content

In this study, extracts of Morus alba leaves were obtained by supercritical CO2 and ultrasound-assisted methods, and the results were compared to those of the conventional Soxhlet extraction. The supercritical extraction resulted in the highest yields of 1.08 and 1.11 wt%, when under the highest pressure conditions investigated (200 bar; 40 and 60 °C, respectively). The ultrasound-assisted n-hexane extraction yielded 0.83 wt% at a temperature of 60 °C, solvent-to-solid ratio of 20 mL g−1, and ultrasound intensity of 43.0 W cm-2. The major compounds identified in the extracts were the triterpenoids lanosterol acetate and lupeol acetate and the phytosterol β-sitosterol. The supercritical CO2 extraction yielded up to 155.74 mg β-sitosterol 100 g−1 leaves at 60 °C and 200 bar. The highest antioxidant activity and total phenolic content was observed for the extract obtained by Soxhlet method, 62.87 μmol g-1 extract and 6.05 mg g-1 extract, respectively159sem informaçãosem informaçãoWe thank Fundação Araucária for the financial support (Proc. Num. 146/2014