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.