Optimization of Flash Extraction Technology of Total Flavonoids from Verbena officinalis L. by Response Surface Methodology and Its Antioxidant Activity in Vivo

Response surface method was used to optimize the extraction technology of total flavonoids from Verbena officinalis L.. On the basis of single-factor test, the extraction conditions (ethanol concentration, ratio of water to materials, extracting time and extraction time) were analyzed and optimized by the Box-Behnken design using the comtent of total flavonoids as index. Meanwhile, the antioxidant capacity was measured by scavenging of DPPH·, hydroxyl free radical and superoxide free radical. The results showed that the optimum extraction conditions were as follows:ethanol concentration was 50%, ratio of raw material to liquid was 1:35 (g/mL), extracting 2 times, and each for 1.5 min. Under the conditions, the content of total flavonoids was (8.282±0.003) mg/g, which close to predicted content of 8.280 mg/g. This method was suitable for the extraction of total flavonoids from Verbena officinalis L with high extraction rate. When the concentration of total flavonoids was 60 μg/mL, the clearance rate on DPPH·, hydroxyl free radical and superoxide free radical was 74.8%, 43.2%, 89.5%, which showed that the total flavonoids of Verbena officinalis L. had a certain antioxidant activity.