Valorization of pawpaw (Carica papaya L.) leaves as a source of polyphenols by ionic liquid-based microwave-assisted extraction: Comparison with other extraction methods and bioactivity evaluation
Duo Cao, Xiaoting Qiao, Yaqian Guo, Pengyu Liu
Abstract
This study aimed to valorize pawpaw (Carica papaya L.) leaves as a rich source of polyphenols through the application of ionic liquid-based microwave-assisted extraction (ILMAE). Initially, the ILMAE process was optimized using response surface methodology (RSM), resulting in a total polyphenols yield of 27.84 ± 0.33 mg GAE/g DW under the optimal conditions: [BMIM]Br concentration of 0.57 mol/L, extraction time of 14 min, microwave power of 460 W, extraction temperature of 77 °C, solvent-to-material ratio of 30 mL/g, and three extraction cycles. Compared to conventional methods such as maceration extraction (ME), heat reflux extraction (HRE), and microwave-assisted extraction (MAE), the ILMAE method exhibited a significantly higher PLTP yield. Furthermore, the PLTP extracts demonstrated strong antioxidant activity against DPPH• and ABTS+• radicals, as well as a significant inhibitory effect on α-glucosidase activity. This work demonstrates that ILMAE is a green and efficient strategy for the valorization of pawpaw leaves.