title: Antioxidant Activity and Total Phenolic and Flavonoid Contents of Hieracium pilosella L. Extracts.
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.
authors.affiliation: University of Nis, Faculty of Technology, Bulevar Oslobodjenja 124, 16000 Leskovac, Serbia; E-Mails:  mstankovic_99@yahoo.com  (M.S.);  nvesna@yahoo.com  (V.N.);  nljubisa@yahoo.com  (L.N.);  dusica.aleksandar@gmail.com  (D.R.).
authors.forename: Ljiljana
authors.initials: L
authors.lastname: Stanojević
authors.forename: Mihajlo
authors.initials: M
authors.lastname: Stanković
authors.forename: Vesna
authors.initials: V
authors.lastname: Nikolić
authors.forename: Ljubiša
authors.initials: L
authors.lastname: Nikolić
authors.forename: Dušica
authors.initials: D
authors.lastname: Ristić
authors.forename: Jasna
authors.initials: J
authors.lastname: Canadanovic-Brunet
authors.forename: Vesna
authors.initials: V
authors.lastname: Tumbas