Feruloylacetone as the model compound of half-curcumin: Synthesis and antioxidant properties

In order to clarify the contribution of phenolic and enolic hydroxyl group to the antioxidant capacity of feruloylacetone, a model compound of half-curcumin, 6-(p-hydroxy-m-methoxyphenyl)-5-hexene-2,4-dione (FT), 6-(p-benzyloxy-m-methoxyphenyl)-5-hexene-2,4-dione (BMFT), 6-(m,p-dihydroxyphenyl)-5-hexene-2,4-dione (DDFT), 6-(p-hydroxy-m-methoxyphenyl)hexane-2,4-dione (DHFT), 6-(p-hydroxy-m-methoxyphenyl)-5-hexene-2,4-diol (THFT), and ethyl 2-(p-hydroxy-m-methoxybenzylidene)-3-oxobutanoate (EOFT) were synthesized. The radical-scavenging abilities of these compounds were tested by trapping 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonate) cationic radical (ABTS+), 2,2′-diphenyl-1-picrylhydrazyl (DPPH), and galvinoxyl radicals. The reductive capacities were screened by quenching singlet oxygen and by inhibiting the oxidation of linoleic acid. They were also employed to inhibit the oxidation of DNA mediated by hydroxyl radical and 2,2′-azobis(2-amidinopropane hydrochloride) (AAPH). In addition, they were applied to protect erythrocytes against AAPH- and hemin-induced hemolysis. The obtained results revealed that the antioxidant capacity of half-curcumin was derived from the phenolic-OH and the conjugated linkage between phenolic and enolic-OH. The enolic-OH itself cannot trap radicals.

Half-curcumin and its derivatives scavenge radicals, reduce oxidants, and protect DNA and erythrocytes.Figure optionsDownload as PowerPoint slideResearch highlights
► Half-curcumin derivatives scavenge radicals, reduce oxidants, and protect DNA and erythrocytes.
► Phenolic hydroxyl scavenges radicals effectively, but enolic hydroxyl cannot.
► Half-curcumin derivatives act as prooxidant in Cu2+/GSH-induce oxidation of DNA.
► More phenolic hydroxyls enhance the antioxidant ability to protect DNA and erythrocytes.