Abstract:

This study aimed to optimize the ultrasonic-assisted extraction of flavonoids from Oenanthe javanica using
single-factor experiments and response surface methodology. The antioxidant activity of the extracted flavonoids was
evaluated. The optimal extraction conditions were determined as follows: the time of ultrasonic-assisted extraction, 62 min;
temperature, 69 ℃; solid-to-liquid ratio, 1:38 (g/mL); and ethanol concentration, 80%. Under these conditions, the
predicted and experimental extraction yield of flavonoids from leaves was 8.238 and 8.201 mg/g mf, respectively. The good
consistency indicated the mathematical model we built could fit experimental data well. The content of flavonoids in leaves
of O. javanica was much higher than in stems. The flavonoids extracted from both parts possessed high total antioxidant
capacity and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging ability and the flavonoids from stems had stronger
antioxidant ability than those in leave. This difference may be caused by the difference in the composition of flavonoids
extracted from stems and leaves.

Key words: Oenanthe javanica, flavonoid, ultrasonic-assisted extraction, response surface methodology, antioxidant activity