In vitro antioxidant activity‐guided fractionation of Daucus carota L. seed extract

Daucus carota Linn (carrot) seeds are medicinally useful in the management of diseases including diabetes mellitus. The present study investigates the in vitro antioxidant activities and phytochemical constituents of several fractions from aqueous seed extract of Daucus carota. D. carota seeds (78.8g) were pulverized and dissolved in 400 mL of distilled water for 24 hours. The crude extract obtained (16.4g, 20.8% yield) was partitioned in water/ethyl acetate (3:1) to yield ethyl acetate fraction (6.2g, 37.8% yield) and aqueous ethyl acetate fraction (7.6g, 46.3% yield) which was subjected to column chromatography. Thirteen (13) fractions obtained were evaluated for their in vitro antioxidant activities and screened for phytochemical constituents. The fractions exhibited in vitro antioxidant activities at 2 – 20 μg/mL with 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activities (IC50 = 1.38 - 22.96 μg/mL), total antioxidant capacity (IC50 = 1.17 - 3.13 μg/mL) and nitric oxide scavenging activities (IC50 = 3.20 - 20.72 μg/mL). Fractions 4 – 8 expressed promising in vitro hydrogen peroxide (H2O2) antioxidant activities with IC50 comparable with that of ascorbic acid and butylated hydroxytoluene. The phytochemical screening of fractions 4 – 8 revealed the presence of alkaloids, flavonoids, and phenolics, which could be responsible for the antioxidant activities. The results suggest that fractions obtained from Daucus carota L. seed extracts possess significant antioxidant potential.