2.9. Free radical scavenging assay

100 μL DPPH-ethanol solution (0.1 mmol/L) was added to 100 μL of various concentrations of FCPS solutions. After incubating in darkness for 10 min, the measurement was taken at 517 nm using a microplate reader. The scavenging capacity of FCPS on hydroxyl free radicals was measured following the instructions. Positive, blank, and background controls were established using Vc (0.25 mg/mL), distilled water, and anhydrous ethanol, respectively.