Optimization protocol and bioactivity assessment for the microwave-assisted extraction of flavonoids from Eucommia ulmoides Oliver seed meal using response surface methodology

Response surface methodology was utilized to optimize the microwave-assisted extraction of flavonoids from Eucommia ulmoides Oliver seed meal. In addition, the optimal processing conditions for the extraction of E. ulmoides seed meal flavonoids were as follows: a processing time of 30 min, a liquid to solid ratio of 54 to 1 (mL/g), an ethanol concentration of 77%, and a temperature of 69 °C. The total flavonoids extraction percentage was 0.6611%. Moreover, the total flavonoids extracted from E. ulmoides seed meal were good for scavenging diphenyl picryl hydrazinyl. The E. ulmoides seed meal total flavonoids exhibited an obvious dose-dependent inhibitory effect on α-glucosidase in the concentration range of 0.05 to 1.0 mg·mL−1. The IC50 value of the E. ulmoides seed meal flavonoids was slightly lower than the IC50 value of acarbose. According to the results of the xanthine oxidase inhibitory activity test, the IC50 value of the E. ulmoides seed meal flavonoids was higher than the IC50 value of allopurinol.