Optimization of extracting total flavonoids from leaves of Rhodomyrtus tomentosa (Ait.) Hassk by response surface methodology

Based on single factor experiments, extraction conditions concluding extraction temperature, ethanol concentration, liquid-solid ratio and extraction time were optimized using response surface methodology. The results showed that the optimal extraction conditions were as follows:extraction temperature 73℃, ethanol concentration 50%, liquid-solid ratio 19∶1 (mL/g) and extraction time 124min, resulting in an extraction efficiency of 5.426% for total flavonoids which was consistent with the predicted value. In addition, total flavonoids from leaves of R. tomentosa had scavenging effect on DPPH with a dose-effect relationship, and the IC50 was 9.797μg/mL.