Abstract:To enhance the utilization of the peel of Citrus sinensis Osbeck ‘Hongjiang’, an optimal extraction process for flavonoids was developed. To this end, an orthogonal experimental design was adopted, and ultrasonic-assisted extraction was performed; the flavonoid yield served as the evaluation index. Subsequently, the inhibitory effects of the extract on α-glucosidase and pancreatic lipase were investigated. The results demonstrated that the optimal conditions included an ultrasonic temperature of 70 ℃, solid-liquid ratio of 1:5, and extraction time of 50 min. The resulting total flavonoid yield was 82.57 mg/g, considerably higher than that achieved by traditional ethanol extraction (23.56 mg/g). The IC50 values of the flavonoid extract from the peel of C. sinensis ‘Hongjiang’ (CSFE) for α-glucosidase and pancreatic lipase were 2.95 mg/mL and 28.54 mg/mL, respectively. The inhibitory effects of CSFE on pancreatic lipase were concentration-dependent between 10 and 50 mg/mL. Moreover, mixed-type inhibition was observed for α-glucosidase and pancreatic lipase. These findings indicate that CSFE exhibited good inhibitory effects against α-glucosidase and pancreatic lipase, providing a theoretical foundation for future research on its hypoglycemic and weight reducing functions.
