Antioxidant capacity, phenol and flavonoid contents in Eryngium amethystinum L. (Apiaceae)

Abstract

The role of reactive oxygen species in many pathological conditions such as cardiovascular diseases or diabetes has been in the focus of research interests in the past decade. Eryngium amethystinum L. (= E. glomeratum Lam.) is a Mediterranean herb, light blue to purple in color. Its young shoots and roots are used as vegetables. Quantity of phenolic substances (total phenol and flavonoid) was determined in methanolic extracts of leaves, stems and flowers of E. amethystinum. In order to estimate reactivity of the extracts with free radicals, their reducing effects, as well as their ability to chelate Fe2+ ions and inhibit lipid peroxidation, antioxidant activity was established using following methods: radical scavenging activity of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free-radical, reducing power, chelating activity and -carotene-linoleic acid assay. Antiradical activity of the extracts in reaction with DPPH free radical was rather modest in comparison with butylated hidroxianisol (BHA). On the other hand, reducing power and chelating activity of the extracts were comparable to the activities of positive controls, BHA and quercetin, respectively. The activity of the extracts was most prominent in reaction with -carotene and linoleic acid. In that assay, there was no difference in activity of stem, flower and BHA, while the activity of leaf was significantly higher (p<0.01). The antioxidant activity of the extracts in most of the performed assays correlated well with the quantity of phenols (0.74<r2< 0.99, p<0.05) and flavonoids (0.57<r2<0.90, p<0.05). The results of this study indicate that E. amethystinum might be a beneficial source of dietary antioxidants.