Mohammad Ali Ebrahimzadeh - Pharmaceutical Sciences Research Center, School of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran.
Afsaneh Tavassoli - Research Center of Natural Resources of Mazandaran, Sari, Iran.

The genus Helichrysum (Asteraceae) is comprised of approximately ۵۰۰-۶۰۰ 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 of H. pseudoplicatum were investigated employing various in vitro assay systems, i.e. ۲,۲-diphenyl-۱-picrylhydrazyl (DPPH)  and nitric oxide radical scavenging, reducing power and hydrogen peroxide scavenging. IC۵۰ for DPPH radical-scavenging activity was ۴۳۸.۹ ± ۱۵.۶ µg/ml. The extract exhibited good reducing power at ۲۵ - ۴۰۰ µg/ml but was not comparable with that of vitamin C. The extract showed good nitric oxide-scavenging activity. IC۵۰ was ۴۷۴.۳ ± ۱۱.۸ µg/ml. It was capable of scavenging hydrogen peroxide in a concentration dependent manner. It showed good activity. Its IC۵۰ was ۱۵۹.۸ ± ۸.۲ µg/ml. The IC۵۰ values for ascorbic acid and BHA were ۲۱.۴ and ۵۲.۰ µg/ml, respectively. The total amount of phenolic compounds in the extract was determined as gallic acid equivalents (۲۲.۷ ± ۳.۱ mg/g of extract) and total flavonoid contents were calculated as quercetin equivalents (۹.۶ ± ۱.۳ 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.

Antioxidant activity, Helichrysum pseudoplicatum, Radical scavenging, Reducing power