The antioxidant activity of Scorzonera parviflora Jacq. roots were assessed by measuring their ability to scavenge ABTS and DPPH radicals. Bioactivity-guided fractionation was utilized to identify the compound(s) responsible for this activity. The most active phase, ethyl acetate, was isolated using column chromatography. The resulting fractions were then purified using preparative TLC on reverse phase and semi-preparative HPLC. The structures of the pure compounds were elucidated by spectral analysis (MS and 1H, 13C, 2D-NMR). Three undescribed phenolic acid derivatives, namely parvifloric acid A (1), B (2), and C (3), and one new sesquiterpene lactone, parviflorin (4) together with seven known compounds were isolated and identified as scopolin (5), scopoletin (6), caffeic acid (7), protocatechuic acid (8), 4,5-O-dicaffeoylquinic acid (9) 3,5-O-dicaffeoylquinic acid (10), and 3,5-O-dicaffeoylquinic acid methyl ester (11). Finally, the pure compounds obtained were tested to evaluate their antioxidant capacities, using ABTS and DPPH radical scavenging potencies. The highest activity was observed with 3,5-O-dicaffeoylquinic acid (10), followed by its methyl ester.

Ankara University Faculty of Pharmacy Department of Pharmaceutical Toxicology Tandogan 06100 Ankara Turkey

Ankara University Faculty of Pharmacy Department of Pharmacognosy Tandogan 06100 Ankara Turkey

Bulent Ecevit University Faculty of Pharmacy Department of Pharmacognosy Zonguldak Turkey

Institute of Organic Chemistry and Biochemistry v v i Academy of Sciences of the Czech Republic Flemingovo nám 2 166 10 Prague Czech Republic

Pharmazeutisches Institut Abteilung Pharmazeutische Biologie Christian Albrechts Universität zu Kiel Gutenbergstraße 76 24118 Kiel Germany

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