Optimization of Ultrasound-Assisted Extraction for Antioxidant Activity in Relation to Rhoifolin Content of Fortunella polyandra using Response Surface Methodology (RSM)

Fortunella polyandra (Ridl) Tanaka or Malayan kumquat, is a family of Rutaceae from Malaysia known for its various active compounds, especially flavonoids. This study aims to verify the optimum condition and correlation leaves extract in by ultrasound-assisted extraction (UAE) antioxidant activities apigenin 7-O-neohesperidoside (rhoifolin) contents using response surface methodology (RSM). Central composite rotatable design (CCD) was performed investigate influence parameters on maximum activity, namely temperatures (X1), times (X2), solvent ratios ethanol:water (X3). The optimal conditions 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity were obtained at time 5 min, temperature 30 °C ratio 70:30, with IC50 value 0.126±0.004 mg/mL. Rhoifolin content ferric reducing potential (FRAP) assay share same °C, 30:70, ethanol:water. Under these conditions, rhoifolin measured 67.83±0.37 ppm, whereas FRAP equivalent recorded 0.22±0.01 All three responses model achieved 95% confidence level. Correlation showed that there no relationship between extract.