Optimization of extraction process and antioxidant activity of total flavonoids from cup plant by response surface method

The extraction of total flavonoids from cup plant was optimized through response surface methodology. According to the Box-Behnken response surface method and on the basis of ethanol extraction and single-factor test,four single factor having significantly effects were selected:liquid-to-solid ratio,extraction time,extraction temperature and alcohol concentration to finish response surface design experiment with four factors and three levels. The extraction yield of total flavonoids as responses was optimized by response surface analysis to obtain the extraction parameters. The antioxidant activity of total flavonoids from cup plant was determined. The optimal extraction conditions of total falvonoids were liquid-to-solidratio of 31:1 (mL/g),extraction time of 129 min,extraction temperature at 38 ℃ for 42% with alcohol concentration. The extraction yield of total flavonoids obtained under these conditions was as high as(38.93±0.012) mg/g which differed with the theoretical value of 0.04%.The extracting of 1 mg/mL total flavonoids(0.51 mg)had strong scavenging capacity on DPPH radicals rate that was 73.06%. Scavenging activity of total flavonoids from cup plant by 0.6 mg/mL against ABTS⁺ free radicals was 100%. Ferric reducing power from total flavonoids of cup plant of by 6 mg/mL was 0.188. Response surface methodology was applicable for the extraction optimization of total flavonoids from cup plant. The total flavonoids from cup plant had strong radical scavenging capacity and a certain ferric reducing power.