Green ultrasound‑assisted extraction of bioactive polyphenols from Inonotus hispidus: Sustainable process with enhanced yield and antioxidant activity.

Ultrasound-assisted extraction (UAE) has emerged as a green and efficient alternative to conventional extraction methods, primarily due to the acoustic cavitation phenomena that minimize solvent consumption and processing time. This study systematically optimized a UAE process for maximized recovery of total polyphenols from Inonotus hispidus. UAE was conducted using a KS-700XDS power-adjustable ultrasonic bath at 50 kHz. In preliminary comparisons, UAE demonstrated more efficacy, affording a total polyphenol content (TPC) of 18.74 mg/g, which exceeded the yields of heat reflux extraction and stirring-assisted extraction by 8.70 % and 14.62 %, respectively. Response surface methodology was subsequently employed to determine the optimal extraction parameters, which were established as an extraction time of 95 min, an ethanol concentration of 60 %, an ultrasonic power of 150 W, and a temperature of 65 ℃. Under these optimized conditions, the experimental TPC reached 25.46 mg/g, representing a 35.86 % increase over the pre-optimized value. A greenness evaluation using the AGREE metric yielded a score of 0.76 for UAE, confirming its environmental sustainability. Antioxidant assays demonstrated that the optimized extract exhibited significantly enhanced radical-scavenging activities and ferric reducing power compared to the unoptimized extract. These findings highlight the critical role of ultrasonic-controlled parameters in maximizing polyphenol yields and validate the proposed method as a highly efficient and sustainable approach for fungal material valorization.