Abstract:

Ultrasonic extraction (UE) of flavonoids from the whole plant of Eupatorium lindleyanum DC was optimized using Box-Behnken design and response surface methodology on the basis of single factor experimental results. The scavenging effect of the extract against DPPH free radicals was also studied. Results indicated that the optimal extraction conditions of flavonoids from the whole plant of Eupatorium lindleyanum DC were liquid-to-ratio of 11.3:1, ultrasonic extraction temperature of 58 ℃ and ultrasonic treatment time of 29 min. The extraction rate of flavonoids under these optimal extraction conditions was 1.142%. It was calculated that the content of flavonoids in Eupatorium lindleyanum DC ranged from 6.556 to 32.78 μg/mL. The scavenging rate of flavonoids from Eupatorium lindleyanum DC against DPPH free radicals was between 46.90% and 61.06% in a dosedependent manner. Compared with other extraction techniques, UE exhibited higher yield and shorter extraction time.

Key words: Eupatorium lindleyanum DC, flavonoid, ultrasonic extraction, Box-Behnken design, antioxidant activity