Phytochemical investigation of and evaluation of the antioxidant activity.

(L.) Cass. ex Maire, syn. (L.), (Asteraceae) is a plant from the central region of Algeria, considerably distributed in all Mediterranean areas. Herein, the antioxidant activity of the three derived fractions [chloroform (CHCl), ethyl acetate (EtOAc) and -butanol (-BuOH)] of the 70% methanol extract of the aerial parts (leaves and flowers), was assessed by using CUPRAC, ABTS, DPPH free radical scavenging, and β-carotene bleaching methods. The results obtained allowed to guide the fractionation of EtOAc and BuOH fractions by CC followed by purification by TLC and reverse phase HPLC. A guaianolide glucoside, 3β-hydroxy-11β,13-dihydrodehydrocostuslactone 8α--(6'-acetyl-β-glucopyranoside) (), never reported in the literature, was isolated together with other known compounds (-). Their structures were elucidated by the extensive use of 1 D- and 2 D-NMR experiments along with ESI-MS analyses and with comparison with literature data.