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-diphenyl2-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.