Synthesis and antioxidant properties of dendritic polyphenols.
Three dendritic polyphenols (generation 1) were synthesized: a syringaldehyde-based dendrimer (1), a vanillin-based dendrimer (2), and an iodinated vanillin-based dendrimer (3). They all showed strong antioxidant activity according to the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical assay. The syringaldehyde dendrimer was twice and 10 times stronger than quercetin and Trolox, respectively. The vanillin-based dendrimer and its more hydrophobic iodinated derivative were also more potent antioxidants than quercetin and Trolox. The DPPH order of potency was 1>2, 3>quercetin>Trolox. All three dendrimers also protected human LDL from free radical attack in a dose-dependent manner. Their order of free radical scavenging was 1>3>2>quercetin>Trolox. The increased hydrophobic nature of the iodinated derivative may have contributed to its better LDL protection than 2. Protection of linoleic acid oxidation was studied by the beta-carotene-linoleate assay. Dendrimer 1 was clearly superior to the other antioxidants in protecting the fatty acid. In case of DNA protection against free radical damage, the order of activity was 1>quercetin>2>3, Trolox. Pro-oxidant effect on copper-induced DNA oxidation showed the following order: quercetin, Trolox>1>2>3. Results of the study show that dendritic antioxidants, even at the generation 1 level, provide promising antioxidant properties for their potential use as drug candidates for diseases associated with oxidative stress.
Lee
Choon Young
CY
Department of Chemistry, Central Michigan University, Dow 343, Mount Pleasant, MI 48859, USA. lee1cy@cmich.edu
Sharma
Ajit
A
Cheong
Jae Eun
JE
Nelson
Julie L
JL
D005419:Flavonoids; D016166:Free Radical Scavengers; D010636:Phenols; D059808:Polyphenols; D011794:Quercetin; D019207:beta Carotene
D005419:Flavonoids; D016166:Free Radical Scavengers; D010636:Phenols; D059808:Polyphenols; D019207:beta Carotene; D011794:Quercetin