Optimization of ultrasonic assisted extraction and biological activity of total polyphenols from Toona sinensis using response surface methodology

Abstract To optimize the extraction process and activity detection of total polyphenols from Toona sinensis. A Box–Behnken design of response surface methodology was employed to further optimize ultrasonic-assisted extraction (UAE) conditions for T. sinensis stems total polyphenols (TSTP). The results showed that optimized extraction conditions were ultrasonic power of 200 W, liquid-solid ratio of 50 mL/g, ultrasonic temperature of 60°C and ultrasonic time of 22 min. Under these conditions, the mean experimental value of extraction yield (8.13%) was achieved, which was about 49.44% higher than that of distilled water leaching extraction. As compared to TSTP, TSTP after purification (TSPTP) had higher purity of 57.70%, which was nearly 45.33% higher than that of TSTP (12.37%). TSPTP had higher α-glucosidase and α-amylase inhibitory activities as well as DPPH· and ABTS·+ scavenging activities with an IC50 value of 0.201, 0.041, 0.27 and 0.07 mg/mL. TSPTP from T. sinensis could be considered as multifunctional bioactive ingredients to be used in anti-hyperglycemic pharmaceutical formulation and antioxidant.