Optimization of ultrasonic-microwave synergistic extraction of cordycepin and antioxidant activity from Cordyceps militaris mycelial symbiont

Abstract

In this study, ultrasonic-microwave synergistic extraction (UMSE) was employed to extract cordycepin from Cordyceps militaris mycelial symbiont. The effects of extraction temperature, extraction time, solid–liquid ratio, ultrasonic power, and microwave power on the extraction of cordycepin were investigated. Using Plackett–Burman design, the significant factors affecting cordycepin content were identified as extraction temperature, solid–liquid ratio, and extraction time. Box–Behnken design was then used to evaluate the interactive effects of these significant factors, and the optimal extraction conditions were determined as follows: solid–liquid ratio of 1:30 g/mL, extraction temperature of 60 °C, extraction time of 29 min, ultrasonic power of 350 W, and microwave power of 350 W. Under the optimal conditions, the cordycepin content reached 6.95 ± 0.05 mg/g. The extract of cordycepin from Cordyceps militaris mycelial symbiont demonstrated greater antioxidant scavenging efficacy against ABTS· radicals than against DPPH· radicals. Compared to traditional extraction methods, UMSE exhibited better antioxidant capacity. Although the scavenging abilities of the cordycepin extract against DPPH· and ABTS· increased with the concentration, compared with VC, the scavenging capacities were not significant.