Phenolic Profile and Antioxidant Activity of Methanolic Extract of Carduus acicularis Bertol. (Asteraceae)

Phenolic acid and flavonoid profiles of Carduus acicularis were investigated for the first time. Eleven phenolic acids and eight flavonoids were identified and quantified in the inflorescences, by high performance liquid chromatography. The main phenolic compounds were found to be: sinapic acid (930.41 ± 21.72 μg/g dw), chlorogenic acid (582.66 ± 13.60 μg/g dw), rutin (545.65 ± 12.82 μg/g dw), apigenin (478.75 ± 11.38 μg/g dw), luteolin (288.46 ± 6.86 μg/g dw) and myricetin (276.32 ± 5.21 μg/g dw). The antioxidant activity of methanolic extract of inflorescences has been investigated, employing four different established testing systems: scavenging activity on 2,2-diphenil-1-picrylhydrazyl (DPPH), 2,2'-azinobis-(3-ethyl-benzothiazoline-6-sulfonate (ABTS) radical cation decolorization assay, ferric reducing antioxidant power (FRAP) and copper reduction antioxidant assays (FRAP). The highest antioxidant activity values were measured by the ABTS assay, among all performed methods.