Abstract

The antioxidant capacity of the flowering aerial parts of Astragalus squarrosus was determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and ferric thiocyanate methods. The phenolic and flavonoid content was also measured. A. squarrosus showed weak free radical scavenging activity with the DPPH method which might be due to its low phenolic constituents (23.3 mg/g) and flavonoid content (26.0 mg/g). Results obtained from ferric thiocyanate (FTC) assay revealed that the extract has antioxidative potential for chain-breaking inhibition of lipid peroxidation as it showed 69.0% inhibition when compared with butylated hydroxytoluene  (BHT)(78.0% inhibition).

Key words: Astragalus squarrosus, antioxidant, phenolics, flavonoids.