Phenolic profile, chemical relationship and antioxidant activity of Iranian Verbascum species

Hydro-ethanolic extracts of flowers from four Verbascum species were evaluated for the phenolic content, composition, and antioxidant activity using Folin-Ciocalteu assay, HPLC-DAD analysis, and DPPH assay, respectively. The highest flavonoid content was detected in V. sinuatum extract from Khoramabad (19.91 mg RE/g DW). The extract of V. pseudo-digitalis from Maymand yielded the highest amount of total phenols, together with the highest apigenin and luteolin levels (55.62 mg GAE/g DW, 12.18 and 88.13 μg/mg DW, respectively), while that of V. songaricum from Ardekan showed the highest naringin content (12.44 μg/mg DW). The extract of V. songaricum from Shirmard exhibited the highest quercetin and rutin levels (1.0 and 24.24 μg/mg DW, respectively), whereas that of V. sinuatum from Ardekan had the highest caffeic acid content (7.78 μg/mg DW). The antioxidant activity of Verbascum samples showed IC50 values from 45.12 to 226.62 μg/mL.