International Research Journal of Pure and Applied Chemistry

We systematically evaluated in vitro the antioxidant activity of magnolol, a natural phenolic phenylpropanoid, using DPPH (1, 1-Diphenyl-2-picrylhydrazyl radical), ABTS [2, 2′-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)], Ferric ions (Fe³⁺) reducing power, superoxide anion and hydroxyl radical-scavenging. In all assays, magnolol and positive controls exhibited effective antioxidant ability. The IC₅₀ values of magnolol were calculated as 25.92, 0.85, 737.56, 29.97, 153.46 μg/mL, respectively, for DPPH, ABTS, Fe³⁺ reducing power, superoxide anion and hydroxyl radical-scavenging. In these five assays, the IC₅₀ values of Trolox were respectively calculated as 5.08, 2.02, 58.92, 160.26, 62.69 μg/mL, while the IC₅₀ values of BHT were respectively 4.17, 1.76, 75.83, 43.31, 202.64 μg/mL. Furthermore, as DPPH and ABTS assays were conducted in organic solutions, while the other assays were finished in aqueous solutions, magnolol is therefore regarded as an effective antioxidant in vitro in both lipid and aqueous media. Its various protective effects may be attributed to the antioxidant. The fact that magnolol could effectively scavenge both DPPH• and ABTS⁺• suggested it may exert antioxidant action in vitro by donating hydrogen atom (H•) or electron (e).