Antioxidant activity of Echinophora platyloba DC essential oil: a comparative study on four different methods

The present study is conducted in order to investigate the antioxidant capacity of Echinophora platyloba DC (Duncan) essential oil (EO), growing wild in west Azerbaijan, Iran, with four different assays. The aerial parts of Echinophora platyloba DC were provided from Maraghe city district, northwest of Iran and its phytochemicals were determined using GC-MS analysis. In order to evaluate and compare the antioxidant activity of the EO, various concentrations (1, 2.5, 5 and 10 mg.ml-1) of the oil and reference antioxidants (ascorbic acid and BHT) were analyzed by four different assays such as 2,2’-azinobis 3-ethylbenzothiazoline-6-sulphonic acid (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), Ferric reducing antioxidant power (FRAP) and β-carotene bleaching test (BCBT). The oil exhibited moderate antioxidant activity with a dose-response in DPPH and ABTS assays and it exhibited strong antioxidant activity in FRAP and BCBT assays. It is concluded that FRAP and BCBT assays are more suitable spectrometric assays for antioxidant capacity evaluation of Echinophora platyloba.