Optimization of ultrasonic-assisted extraction of flavonoids with ethanol from ginkgo leaves by response surface methodology

Response surface methodology (RSM) was applied to predict optimum conditions for ultrasonic-assisted extraction of flavonoids from ginkgo leaves. A central composite design involving ultrasonic time, extracting temperature and extracting time was used, and second-order model for flavonoid purity was employed to generate the response surface. The optimized condition was as follows: ultrasonic time 21.66 min, extracting temperature 39.34 °C and extracting time 2.01 h. The predicted flavonoid purity at condition was 40.75 mg/g. Experimental verification gave the value of 40.62 mg/g.