Evaluation of phenolic content and antioxidant activity of Iranian caraway in comparison with clove and BHT using model systems and vegetable oil

Abstract

SummaryAntioxidant activity (AA) of phenolic compounds in methanolic extract of Iranian caraway was compared with clove. Total phenolic content of caraway and clove extracts determined by the Folin‐Ciocalteu method, were 13.76 and 243.91 mg g−1 dry matter respectively, expressed as tannic acid equivalents, and total flavonoid content of extracts were 2.6 and 5.0 mg g−1 dry matter, respectively, expressed as epicatechin equivalents. The extracts were screened for their potency as antioxidant using various in vitro models, such as β‐carotene–linoleate, ferric thiocyanate, 1,1‐diphenyl‐2‐picryl hydroxyl (DPPH) radical, hydroxyl radical (•OH) and reducing power model systems. AA of BHT was also determined in model systems. AA of methanolic extracts at different concentrations of total phenolic content according to β‐carotene bleaching and ferric thiocyanate methods expressed as AA (per cent inhibition relative to control) ranged from 82% to 96%.The scavenging effect of both extracts on DPPH and •OH radicals were 23–40% and 3.5–12.7%, respectively, which were comparable with BHT as a synthetic antioxidant. Extracts with high content of total phenolic compounds exhibited also good reducing power.