Comparison of antioxidant abilities of magnolol and honokiol to scavenge radicals and to protect DNA

► The antioxidant properties of magnolol and honokiol were compared in many experimental systems. ► Magnolol and honokiol were active in reducing ONOO− and 1O2 and in trapping ABTS+ and DPPH. ► Honokiol was more active to protect DNA against Cu2+/GSH-induced oxidation of DNA than magnolol. ► Honokiol trapped 2.5 radicals and magnolol trapped 1.8 radicals in inhibiting AAPH-induced oxidation of DNA. ► The intramolecular hydrogen bond hindered the antioxidant effectiveness of magnolol.