title: Tyrosinase inhibitory effects and antioxidative activities of novel cinnamoyl amides with amino acid ester moiety.
abstract: Nine cinnamoyl amides with amino acid ester (CAAE) moiety were synthesized by the conjugation of the corresponding cinnamic acids (cinnamic acid, 4-hydroxy cinnamic acid, ferulic acid and caffeic acid) with amino acid esters, and their inhibitory effects on the activities of mushroom tyrosinase were investigated, using l-3,4-dihydroxyl-phenylalanine (l-DOPA) as the substrate. Among these CAAE amides, ethyl N-[3-(4-hydroxy-3-methoxyphenyl)-1-oxo-2-propen-1-yl]-l-phenylalaninate (b(4)) showed the strongest inhibitory activity; the IC(50) was 0.18 μM. The IC(50) values, inhibition types, inhibition mechanisms and kinetics of all these CAAE amides were evaluated. A structure-activity relationship (SAR) study found that the inhibitory effects were potentiated with the increasing length of hydrocarbon chains at the amino acid esters and also influenced by the substituents at the styrene groups. Furthermore, the hydroxyl radical scavenging and anti-lipid peroxidation activities of four CAAE derivatives were also investigated. Among these compounds, b(3) (ethyl N-[3-(3,4-dihydroxyphenyl)-1-oxo-2-propen-1-yl]-l-phenylalaninate) and b(4) exhibited potential antioxidant activities.
authors.affiliation: College of Light Industry and Food Science, South China University of Technology, Guangzhou 510640, Guangdong, PR China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Fan
authors.forename: Hong
authors.initials: H
authors.lastname: Jiang
authors.forename: Er-Dong
authors.initials: ED
authors.lastname: Yuan
authors.forename: Jian-Xun
authors.initials: JX
authors.lastname: Zhang
authors.forename: Zheng-Xiang
authors.initials: ZX
authors.lastname: Ning
authors.forename: Sui-Jian
authors.initials: SJ
authors.lastname: Qi
authors.forename: Qing-Yi
authors.initials: QY
authors.lastname: Wei
mesh_terms: D000363:Agaricales / Q000201:enzymology*; D000577:Amides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D000596:Amino Acids / Q000032:analysis; D000975:Antioxidants / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D002934:Cinnamates / Q000737:chemistry*; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000494:pharmacology*; D004952:Esters / Q000032:analysis; D005656:Fungal Proteins / Q000037:antagonists & inhibitors*; D015394:Molecular Structure; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors*; D013329:Structure-Activity Relationship
chemical_list: D000577:Amides; D000596:Amino Acids; D000975:Antioxidants; D002934:Cinnamates; D004791:Enzyme Inhibitors; D004952:Esters; D005656:Fungal Proteins; C029010:cinnamic acid; D014442:Monophenol Monooxygenase