Isoeugenol-based novel potent antioxidants: synthesis and reactivity.

We are attempting to develop the novel phenolic synthetic antioxidants aimed at retarding the effects of free radicals and oxidants. The phenolic compounds (7-12) were synthesized by Friedel-Crafts alkylation of isoeugenol (1) and phenol derivatives (2-6) and their structures were determined by spectroscopic methods. All the synthesized phenolic compounds (7-12) except 12 are new. Antioxidant and radical scavenging activities of synthesized compounds (7-12) were determined by using various in vitro assays such as 1,1-diphenyl-2-picrylhydrazyl free radicals (DPPH), 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radicals (ABTS(+)), and superoxide anion radicals (O(2)(-)) scavenging, ferric reducing antioxidant power (FRAP) and total antioxidant activity by ferric thiocyanate. The antioxidant activities of compounds were compared with standard antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and trolox as positive controls. The results showed that the synthesized compounds, especially 10 and 11, had better properties than standard antioxidants (BHT, BHA and trolox).