Antioxidant Activity of the Bulb and Aerial Parts of Ornithogalum sintenisii L (Liliaceae) at Flowering Stage

Purpose: Ornithogalum sintenisii is an Iranian species with little known about its pharmacological effects. The purpose of the present study was to investigate some antioxidant properties of the plant. Methods: The antioxidant potency of the freeze-dried methanol extract of O. sintenisii bulbs and aerial parts were investigated by evaluating the following parameters: linoleic acid peroxidation, 1,1-diphenyl-2-picryl hydrazyl radical (DPPH), scavenging of nitric oxide and hydrogen peroxide as well as reducing power and Fe^2+ chelating activity, using standard methods. Phenol and flavonoid contents were determined as gallic acid and quercetin equivalents, respectively. Results: The aerial parts contained higher phenol and flavonoid contents than the bulbs. IC50 for DPPH radical-scavenging activity was 368 ± 15 and 669 ± 25 μg ml^-1 for aerial parts and bulbs, respectively. The reducing power of the extracts was less than that of vitamin C (p 0.01) with the aerial parts showing stronger activity than the bulbs (p 0.01). The extracts did not show any activity in the peroxidation test but displayed good H2O2 radical scavenging activity compared with quercetin (IC50=52.0± 3.1 μg ml^-1) which was used as positive control. Conclusion: The bulb and aerial parts of O. sintenisii aerial parts (at flowering stage) exhibited good but varying levels of antioxidant activities in nearly all the models studied.