An investigation on antioxidant and antimicrobial activities of four Inula helenium L. taxa

The antioxidant activities of methanol (ME), ethanol (EE), water (WE) and ethyl acetate (EAE) extracts of four Inula helenium L. taxa (I. helenium ssp. orygalis (Boiss.) Grierson, I. helenium ssp. pseudohelenium Grierson, I. helenium ssp. turcarasemosa Grierson and I. helenium ssp. vanensis Grierson) were investigated. The phosphomolybdenum assay, β-carotene–linoleate bleaching and DPPH radical scavenging activity were used to evaluate the antioxidant capacity. The total phenolic contents determined by Folin-Ciocalteu assay of the extracts ranged from 4.18 to 102.91 mg gallic acid equivalents (GAE)/g dry extract. The extracts showed considerable effect on reducing the oxidation of β-carotene. The highest radical scavenging activity was obtained for ME of I. helenium ssp. orygalis in DPPH assay. ME, EE and EAE of four Inula helenium taxa showed significant antibacterial activity against 13 bacteria tested. WEs had no inhibitory effect against bacteria tested except for I. helenium ssp. orygalis. EE of I. helenium ssp. orygalis was only effective against C. albicans.