Determination of the chemical composition and in vitro antioxidant activities of essential oil and methanol extracts of Echinophora platyloba DC

This study was designed to examine the chemical composition and in vitro antioxidant activity of essential oil and methanol extracts of Echinophora platyloba from Iran. Gas chromatography (GC) and GC/MS (mass spectrometry; MS) analysis of the essential oil resulted in the identification of 29 compounds, which comprised 97.4% of the oil. The main constituents were found to be: (Z)-beta-ocimene (26.7%), Delta-3-carene (16.2%) and limonene (6.6%). Antioxidant activities of the essential oil and the methanolic extracts from E. platyloba were evaluated using three different test systems, namely 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, beta-carotene-linoleic acid bleaching and reducing power assays. In the DPPH system, the highest radical-scavenging activity was shown by the polar sub-fraction of methanol extract (71.2 +/- 1.11 mu g mL(-1)). Also in the second case, the relative inhibition capacity (%) of the essential oil (68.0 +/- 1.14%) was found to be the stronger one. In addition, the amounts of total phenol components in the polar sub-fractions of methanolic extract (67.5 +/- 0.48 mu g mg(-1)), nonpolar sub-fractions of methanol extract (35.3 +/- 0.12) and the oil (83.3 +/- 0.24 mu g mg(-1)) were determined.