Abstract

OBJECTIVES, Eryngium (E.) caucasicum was found as a new cultivated vegetable plant in northern Iran and used in several local foods. Little information is available on biological properties of E. caucasicum. In this work antioxidant activity of flavonoid-rich fraction of this plant was investigated by eight in vitro assay systems. MATERIALS AND METHODS, 1,1-diphenyl-2-picryl hydrazyl radical (DPPH), nitric oxide and hydrogen peroxide scavenging activities, Fe2+ chelating ability, reducing power and hemoglobin-induced linoleic acid peroxidation were used to evaluate antioxidant activities. Antihemolytic activities were evaluated against CuOOH and H2O2 induced hemolysis in rat erythrocyte. RESULTS, IC50 for DPPH scavenging activity was 391.2 +/- 14.9, 706.6 +/- 22.3 and 779.7 +/- 16.7 mu g ml-1 for aqueous (AQ), ethyl acetate (EA) and n-hexane (HE) fractions, respectively. There was no difference between reducing power of AQ fraction activity and vitamin C (p > 0.05). IC50 for NO radical-scavenging activity was in order of AQ (133.5 +/- 6.2 mu g ml(-1)) > EA (350.1 +/- 14.8 mu g ml(-1)) > and HE (639.9 +/- 21.7 mu g ml(-1)) fractions, respectively. Extracts showed weak Fe2+ chelating ability. HE fraction showed better activity (173.5 +/- 9.6 mu g ml(-1)). Extracts exhibited weak hydrogen peroxide scavenging activity but exhibited very good antioxidant activity against the hemoglobin-induced linoleic acid peroxidation. There was no significant difference between AQ fraction and vitamin C (p > 0.01). Fractions delayed the onset of the CuOOH induced hemolysis. AQ fraction showed very high total phenol and flavonoid contents which was higher than other fractions. High phenol and flavonoid content of AQ fraction may lead to its better antioxidant activity. CONCLUSIONS, E. caucasicum fractions exhibited different levels of antioxidant and antihemolytic activities in all tested models. These results can be useful as a starting point of view for further applications of E. caucasicum aerial parts or its constituents in pharmaceutical preparations.