Antioxidant activity and phenolic compounds of fractions from Portulaca oleracea L.

Portulaca oleracea fractions obtained from the crude extract of the plant by reversed-phase separation were investigated for their antioxidant activities and phenolic compounds content. Five fractions were classified based on optical absorption between the wavelength range of 200–400 nm. Fraction 3 displayed higher absorption than the other fractions. The total amount of quantified phenolics in this fraction was found to be quite high compared to that of crude extract. Chlorogenic, caffeic, p-coumaric, ferulic and rosmarinic acids were the free phenolic acids, and quercetin and kaempferol were the free flavonoids detected in Fraction 3. IC₅₀ value of crude extract was found to be 511.8 μg/ml whereas Fraction 3 exhibited an IC₅₀ value of 154.1 μg/ml. TEAC of Fraction 3 was found to be almost four times higher than that of the crude extract. Fraction 3 was also found to show the highest lipid peroxidation inhibiting capacity, determined by TBARS assay.