title: Synthesis and antioxidant properties of dendritic polyphenols.
abstract: 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.
authors.affiliation: Department of Chemistry, Central Michigan University, Dow 343, Mount Pleasant, MI 48859, USA. lee1cy@cmich.edu
authors.forename: Choon Young
authors.initials: CY
authors.lastname: Lee
authors.forename: Ajit
authors.initials: A
authors.lastname: Sharma
authors.forename: Jae Eun
authors.initials: JE
authors.lastname: Cheong
authors.forename: Julie L
authors.initials: JL
authors.lastname: Nelson
mesh_terms: D005419:Flavonoids; D016166:Free Radical Scavengers; D010636:Phenols; D059808:Polyphenols; D011794:Quercetin; D019207:beta Carotene
chemical_list: D005419:Flavonoids; D016166:Free Radical Scavengers; D010636:Phenols; D059808:Polyphenols; D019207:beta Carotene; D011794:Quercetin