Polyphenols and antioxidant capacity of selected Compositae species

Species belonging to the Compositae family are known for their rich content of phenolic compounds and flavonoids with notable antioxidant properties. Given the increasing demand for natural antioxidants in various industries, this study aims to evaluate the total phenolic and flavonoid content alongside antioxidant activities of ethanolic extracts of six Compositae species; to identify interspecific differences and highlight their potential for use in pharmaceutical, cosmetic, and food sectors. The investigated species include Centaurea salonitana, C. atropurpurea, Achillea atrata, A. clavennae, Filago arvensis, and Xeranthemum annuum. Phenolic content was quantified utilizing the Folin–Ciocalteu method (GAE), while flavonoid content was measured as rutin equivalent (RuE). The antioxidant activity was determined via the DPPH assay (IC50 values). Significant interspecific variation was observed; notably, Achillea atrata exhibited the highest phenolic content, whereas Centaurea salonitana was distinguished by its elevated flavonoid content.