Extraction and antioxidant activities of total flavonoids from Myrica rubra leaves

【Objective】To develop and utilize the abundant resource of flavonoids in Myrica rubra leaves.【Methods】The optimum extraction conditions of total flavonoids from Myrica rubra leaves were discussedby response surface analysis in this paper,and the antioxidant activities of total flavonoids were also in-vestigated through the measurement of total antioxidant capacity,DPPH scavenging activity and reducingpower for total flavonoids.【Results】The results under the experimental conditions showed that the opti-mal parameters for total flavonoids extraction process were determined as follows: extraction temperature60 ℃,ethanol concentration 60%,liquid-solid 60∶1 and ultrasonic power120 W. The total flavonoidsyield obtained under such conditions was 11.56%. IC50 for total flavonoids on scavenging DPPH was 5.62g·L- 1. and the scavenging rate against DPPH free radicals could reached to 94.8%. Total flavonoids in Myrica rubra leaves maintained higher antioxidant capacity and reducing power in comparison with L-ascorbic acid under the same conditions.【Conclusion】In this regard,we have optimized the extractionconditions of total flavonoids in Myrica rubra leaves through response surface analysis and measured theirantioxidant activities as well,which would provide reliable scientific instruction on the exploitation of fla-vonoids resource in Myrica rubra leaves.