DNA damage protection, antioxidant and free-radical scavenging activities of Myriophyllum alterniflorum DC (Haloragaceae) vegetative parts

Abstract DNA damage induced by free radicals is associated with mutation-based health impairment and cancers. The protective effect of five different extracts from an aquatic macrophyte, the alternate water-milfoil Myriophyllum alterniflorum DC (Haloragaceae), is investigated on the DNA disruption mediated by hydroxyl (HO•) and hydroperoxyl (HOO•) radicals, and their antioxidant activity on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and O2 •−. Indeed, M. alterniflorum is supposed to be a good candidate for DNA protection as this species was recently used in ecological surveys as a bioindicator of water quality because of its ability to cope with and to reflect the heavy-metal pollution through variations of antioxidant contents. Moreover, preliminary results indicated higher levels of scavengers specialized in reactive oxygen species reduction, than common medicinal plants. Acetone and ethanol extracts from vegetative parts limit significantly the oxidative damage of plasmid DNA induced by Fenton-reaction reactive oxygen species. The radical antioxidant activities of acetone and aqueous extracts are higher than those of other solvents: [DPPH] IC50 = 2.4 ± 0.2 mg.ml–1 and [O2 •−] AI50 = 220.0 ± 14.1 μg.ml–1, respectively. Protection towards free radicals is correlated with high contents of antioxidant compounds in acetone extracts [phenol compounds: 21.00 ± 0.69 mg gallic acid.g–1 DW (dry weight)] and aqueous extracts (flavonoids: 125.48 ± 1.26 mg rutin.g–1 DW). Myriophyllum alterniflorum can be regarded as a promising natural-product source of antigenotoxics and antioxidants and could be envisaged for therapeutic purposes.