Determination of Antioxidant Capacity of Astragalus halicacabus Lam.

Abstract

In this study, the total phenolic and flavonoid contents, total antioxidant capacity, free radical scavenging activities, ascorbic acid levels of the endemic Astragalus halicacabus Lam. species growing in Turkey were thoroughly evaluated. The total antioxidant capacity of the leaves was determined as 10.32±0.30 mM ascorbic acid/g, while total phenolic and total flavonoid contents were 4.29±0.12 mg gallic acid/g and 3.54±0.22 mg quercetin/g, respectively. The ascorbic acid content was measured as 48.46±0.79 mg/100 g. DPPH(2,2-difenil-1-pikrilhidrazil) and ABTS ABTS (2,2-azino-bis-3-etilbenzotiyazolin-6-sülfonik asit) radical inhibition values were 56.15% and 54.60%, indicating similar activity yet remaining lower than those of the positive controls. In contrast, the plant exhibited markedly higher superoxide radical scavenging activity at 95.12 µg/ml (70.46%), clearly exceeding the positive control (49.28%). Metal chelation inhibition was found to be 51.66% with an IC₅₀ of 43.17±0.68 µg/ml, while hydroxyl radical inhibition reached 67.09%. Hydrogen peroxide scavenging produced a maximum inhibition of 58.54%, with an IC₅₀ value of 66.29±1.23 µg/ml. Overall, the strong superoxide radical scavenging capacity highlights the selective yet potent antioxidant behavior of the plant. Although its hydroxyl radical, hydrogen peroxide scavenging, and metal chelating activities were comparatively lower than those of the reference antioxidants, the plant still demonstrates meaningful antioxidant potential. These findings suggest that Astragalus halicacabus Lam., with its rich phenolic profile and notable vitamin content, represents a valuable natural antioxidant source with promising potential in pharmacology, functional food development, and natural antioxidant formulations, while also contributing important insights into the species’ biochemical characteristics and supporting its possible therapeutic relevance in future research. © 2026, Iğdır University. All rights reserved.