Screening of in vitro antioxidant activity of methanolic leaf and root extracts of Hypochaeris radicata L. (Asteraceae)

The aim of present study was to estimate the total phenolic and flavonoid contents and to investigate in vitro antioxidant potential of methanolic leaf and root extracts of the herb, Hypochaeris radicata L. (Asteraceae). Antioxidant activity was assessed by using 2,2-diphenyl-1-picryl-hydrazyl (DPPH•) assay, reducing power activity, [2,2’-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid)] ABTS•+ assay and ferrous ion chelating activity. Here, butylated hydroxytoluene (BHT), ascorbic acid (ASA), trolox and EDTA were used as standard antioxidants. The total phenolic and flavonoid contents were also determined and expressed in gallic acid and quercetin equivalent respectively. The results of the study indicate that the methanolic extracts of the leaf and root of H. radicata posses significant scavenging activity against DPPH• (97.99% for leaf and 96.44% for root at 250μg/ml each) and ferrous ions chelating activity (38.69% for leaf and 40.52% for root at 5000μg/ml each), reducing power activity (1.38 absorbance at 600µg/ml for leaf, 0.45 absorbance at 700 µg/ml for root) and free radical scavenging activity (ABTS•+) (2706.73 for leaf and 2028.37μmol for root TE/g). The free radical scavenging and antioxidant activities may be attributed to the presence of adequate phenolic (gallic acid content is 125.5µg/10mg in leaf and 133.06µg/10mg in root) and flavonoid compounds (105.76µg/2mg in leaf and 55.16µg/2mg in root). This study revealed that the methanolic extracts of both leaf and root of H. radicata has demonstrated significant antioxidant activity.