Influence of enzyme-aided extraction and ultrasonication on the phenolics content and antioxidant activity of Paeonia officinalis L. petals

Abstract

Peony is a less utilized herbaceous plant of ornamental and medicinal relevance. The petals are rich in bioactive phenolics and hence, the develop­ment of efficient extraction is required for maximum recovery and bioactivity. In this study, the optimal conditions for the ultrasound-assisted extraction of peony phenolics were first investigated by comparing to conventional extract­ion and testing the data fit by mathematical models (linear, two factor inter­actions, quadratic) followed by investigation of cellulase pre-treatment com­bined with ultrasonication. High amounts of flavonoids, phenolics and tannins were extracted in 30 min under ultrasound conditions of 150 W, 40 kHz, 50 % amplitude, in 70 % ethanol with 50/1 solvent/solid ratio. A further cellulase pre-treatment at 40 °C for different incubation times combined with ultrasonic­ation facilitated the extraction of anthocyanins (720.48 mg/100 g DW), phen­olics (3985.50 mg/100 g DW), flavonoids (2369.28 mg/100 g DW) and tannins (8917.81 mg/100 g DW). Good antioxidant activities by FRAP (350.03 mg ascorbic acid/100 g DW) and DPPH (inhibition values >80 %) were registered showing great potential for developing high-value bioingredients. The FTIR analysis revealed the presence of characteristic functional groups. The hereby-combined extraction methods could be extended to other peony species.