Abstract

The brown alga, Colpomenia sinuosa was subjected to DPPH (1,1-diphenyl-2-picryl hydrazyl), nitric oxide radical, hydrogen peroxide, scavenging of ABTS radical and Total antioxidant capacity (TAC) inhibitory assays to assess its antioxidant property. The dimethyl sulphoxide (DMSO) and methanol extracts showed highest antioxidant activity in DPPH (96.56 and 88.57%), nitric oxide radical (81.2 ± 4.1% and 76.69 ± 3.1 %), hydrogen peroxide (70.7 ± 3.5 and 56.6 ± 2.0%) and ABTS (76.8 ± 3.8% and 74.0 ± 2.8%). The moderate activity was observed in total antioxidant capacity (60.3 ± 4.3 and 57.0 ± 2.0) assay. The activity was higher and comparable to that of commercial antioxidants butylated hydroxy anisole (BHA) (87.38 ± 1.32%) and butylated hydroxy tolune (BHT) (56.05 ± 0.19%) at 2 mg/ml concentration. The significant free radical scavenging activity of C. sinuosaindicated that it could be a potential source for natural antioxidant lead molecules.

Key words: ABTS, Colpomenia sinuosa, DPPH, hydrogen peroxide, nitric oxide radical.