antioxidant properties of helichrysum pseudoplicatum nab

the genus helichrysum (asteraceae),is comprised of approximately 500-600 species and used for the treatment of a variety of pathological conditions in folk medicine in many countries. in this study, antioxidant activities of aerial parts ofh. pseudoplicatum were investigated employing various in vitro assay systems, i.e. 2,2-diphenyl-1-picrylhydrazyl (dpph) and nitric oxide radical scavenging, reducing power and hydrogen peroxide scavenging. ic50 for dpph radical-scavenging activity was 438.9 ± 15.6 µg ml-1. the extract exhibited good reducing power at 25 - 400 µg ml-1 but was not comparable with that of vitamin c. the extract showed good nitric oxide-scavenging activity. ic50 was 474.3 ± 11.8 µg ml-1.it was capable of scavenging hydrogen peroxide in a concentration dependent manner. it showed good activity. its ic50 was 159.8 ± 8.2 µg ml-1.the ic50 values for ascorbic acid and bha were 21.4 and 52.0 µg ml-1, respectively. the total amount of phenolic compounds in the extract was determined as gallic acid equivalents (22.7 ± 3.1 mg /g of extract) and total flavonoid contents were calculated as quercetin equivalents (9.6 ± 1.3 mg /g of extract) from a calibration curve. this plant contained low amount of total flavonoids and phenolic compounds. its moderate antioxidant activities may be attributed to its low levels of phenols and flavonoids.