In this study, response surface methodology (RSM) was used to optimize the conditions for the extraction of total
flavonoid content (TFC) and determine the free radical scavenging activity (IC50 value) from Ferulago angulata extract by
ultrasound bath at constant temperature. The investigated factors in this method were the solvent ratio (ethanol/water at 0 to
100%) and extraction time (4–8 min). Experiments were carried out based on a central composite design. The results showed that
the extraction conditions had a significant effect on the IC50 value and TFC extraction. The optimal conditions for TFC (0.56
mgRE/g) included ethanol content and extraction time and were determined to be 49.49% (v/v) and 7 min and 39 sec,
respectively. Furthermore, the IC50 value (1.13 mg/g) was 98.27% (v/v) and 8 min. It was also found that RSM in optimizing
extraction conditions, especially in predicting TFC and IC50 values, is an efficient method. These optimized conditions allow the
rapid and maximum extraction of bioactive compounds from F. angulata.