Optimization for ultrasound-assisted extraction of polysaccharides with antioxidant activity in vitro from the aerial root of Ficus microcarpa

• Polysaccharides from aerial roots of Ficus microcarpa (FMPS) were prepared.
• Conditions of ultrasound-assisted extraction for FMPS were investigated by central composite design.
• FMPS showed strong Fe2+ chelating and moderate H2O2 scavenging activities.

In this study, optimization of ultrasound-assisted extraction and antioxidant activity of polysaccharides from the aerial root of Ficus microcarpa (FMPS) were investigated. The optimal conditions for extraction of FMPS were determined as followings: ultrasound power 200 W, ultrasound temperature 70 °C, extraction temperature 74 °C, liquid–solid ratio 35, extraction time 238 min, ultrasound time 49 min. The experimental yield of FMPS (3.44%) obtained under these conditions was well agreement with the value predicted by the model. In addition, Fourier transform-infrared spectroscopy and antioxidant activity assays revealed that FMPS were acidic polysaccharides and had strong Fe2+ chelating activity and moderate hydrogen peroxide scavenging effect. Further work on the purification, structure characterization and antioxidant activity in vivo of FMPS is in progress.