Synthesis and antioxidant properties of novel benzimidazoles containing substituted indole or 1,1,4,4-tetramethyl-1,2,3,4-tetrahydro-naphthalene fragments

Some 6 -fluoro-5-substituted-benzimidazole derivatives in which indole and 1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene groups were attached to the 2-position of the benzimidazole ring were synthesized and tested for antioxidant properties in vitro. Almost all the synthesized compounds at the 10(-3)M concentrations showed superoxide anion scavenging activity. Compounds 5, 3, 9, 4, 17 and 13 have strong inhibitory effects on superoxide anion formation (98%, 93%, 91%, 88%, 85% and 81%, respectively) at 10(-3) M concentration and these results are better than 30 IU of superoxide dismutase (SOD) (76%). Compound 11 is the most effective scavenger of 2,2-diphenyl-1-picrylhydrazyl (DPPH) stable free radical at 10(-3) M (61%) concentration.