<i>In vitro</I> antioxidant and free radical scavenging activity of <i>Leonurus cardiaca</I> subsp. <i>Persicus</i>, <i>Grammosciadium platycarpum</i> and <i>Onosma demawendicum</i>

Abstract

Antioxidant activity of the aerial parts of Leonurus cardiaca subsp. Persicus, Grammosciadium platycarpum and Onosma demawendicum were investigated employing six in vitro assay systems. IC₅₀ for 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical-scavenging activity was in the order: O.
demawendicum (221 ± 11.7) > L. cardiaca (144 ± 12.1) > G. platycarpum (45 ± 2.1) μgml^-1, respectively. The extracts showed very good nitric oxide-scavenging and Fe²⁺ chelating ability activity. The L. cardiaca subsp. Persicus showed Fe²⁺ chelating ability activity as ethylenediaminetetraacetic acid (EDTA) (IC₅₀ were 20 versus 18 μgml^-1). None of the extracts exhibited good antioxidant activity in linoleic acid model. The extracts showed good reducing power that was better than vitamin C (p < 0.05). G. platycarpum and L. cardiaca subsp. Persicus had higher total phenolic and flavonoid contents than O. demawendicum. The total phenolic compounds in the extracts were determined as gallic acid
equivalents, and total flavonoid contents were calculated as quercetin equivalents from a calibration curve.

Keywords: Antioxidant activity, Fe²⁺ chelating, 1,1-diphenyl-2-picryl hydrazyl (DPPH), phenol, Leonurus cardiaca, Grammosciadium platycarpum, Onosma demawendicum