Gynura segetum, family Compositae (Asteraceae) is a cultivated species and known to possess various medicinal properties for
treatment of cancer, inflammation, diabetes, hypertension and other skin afflictions. The antioxidant activities were studied
using 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging and β-carotene-linoleate model system. The amounts of total phenolic
and flavonoid in the extract were also determined. The ethyl acetate fraction consistently exhibited the highest antioxidant
activity based on the tests performed. The ethyl acetate fraction was potent at DPPH scavenging activity with the lowest EC50
(91.65ug/ml). Antioxidant activity based on the bleaching rate of β-carotene showed percentage inhibition of 81% comparable
to Quercetin (94%) at 250ug/ml. The total phenolic and flavonoid content of ethyl acetate fraction were 214.9ug/ml gallic acid
equivalent of extract and 67.5ug/ml quercetin equivalent of extract, respectively. The results of this study suggested the
correlation between the antioxidant activity potential and total phenolic and flavonoid contents of the ethyl acetate fraction.
Phenolic compounds present in the plants may be a major contributor of antioxidant activities. In conclusion, the ethyl acetate
fraction of Gynura segetum’s leaf is a potential source of natural antioxidants with potent antioxidant activities.