Abstract: The antioxidant activity of water, ethanol and methanol Hieracium pilosella L.
extracts is reported. The antioxidative activity was tested by spectrophotometrically
measuring their ability to scavenge a stable DPPH• free radical and a reactive hydroxyl
radical trapped by DMPO during the Fenton reaction, using the ESR spectroscopy. Total
phenolic content and total flavonoid content were evaluated according to the Folin-
Ciocalteu procedure, and a colorimetric method, respectively. A HPLC method was used for
identification of some phenolic compounds (chlorogenic acid, apigenin-7-O-glucoside and
umbelliferone). The antioxidant activity of the investigated extracts slightly differs
depending on the solvent used. The concentration of 0.30 mg/mL of water, ethanol and
methanol extract is less effective in scavenging hydroxyl radicals (56.35, 58.73 and 54.35%,
respectively) in comparison with the DPPH• radical scavenging activity (around 95% for all
extracts). The high contents of total phenolic compounds (239.59–244.16 mg GAE/g of dry
extract) and total flavonoids (79.13–82.18 mg RE/g of dry extract) indicated that these
compounds contribute to the antioxidative activity.