Ley Jakob P, Bertram Heinz-Jürgen
Symrise, Research & Development, P.O. Box 1253, 37601 Holzminden, Germany.
J Agric Food Chem. 2003 Jul 30;51(16):4596-602. doi: 10.1021/jf034286d.
Some N-(hydroxycinnamoyl)-L-tyrosine and L-DOPA alkyl esters were synthesized and evaluated as a variation of the clovamide (N-caffeoyl-L-3,4-dihydroxyphenylalanine) structure, a known antioxidant found in red clover. The amides were prepared in good yields starting from methyl and dodecylesters of L-tyrosine and L-DOPA by reacting with the N-hydroxysuccinimidyl esters of ferulic, sinapic, and acetyl-protected caffeic acid, respectively. In the DPPH* (2,2-diphenyl-1-picrylhydrazyl) and superoxide radical quencher assays they showed radical scavenging activity equal to or higher than those of the standard antioxidants ascorbic acid and tocopherol. The antioxidative potentials of the clovamide derivatives against bulk lipid oxidation, as determined by the accelerated autoxidation of oils, were equal to or higher than those of the standard antioxidants; some of the compounds were able to protect an emulsion of linoleic acid/beta-carotene against oxidation. N-Caffeoyl L-tyrosine methyl ester and the N-cinnamoyl L-DOPA alkyl esters especially were potent antioxidants in bulk lipids and moderate protectants in emulsions.
合成了一些N-(羟基肉桂酰基)-L-酪氨酸和L-多巴烷基酯,并将其作为红车轴草中已知的抗氧化剂丁香酰胺(N-咖啡酰-L-3,4-二羟基苯丙氨酸)结构的变体进行评估。通过分别与阿魏酸、芥子酸和乙酰保护的咖啡酸的N-羟基琥珀酰亚胺酯反应,从L-酪氨酸和L-多巴的甲酯和十二烷基酯出发,以良好的产率制备了这些酰胺。在DPPH*(2,2-二苯基-1-苦基肼)和超氧阴离子自由基淬灭试验中,它们表现出与标准抗氧化剂抗坏血酸和生育酚相当或更高的自由基清除活性。通过油脂的加速自动氧化测定,丁香酰胺衍生物对大量脂质氧化的抗氧化潜力与标准抗氧化剂相当或更高;一些化合物能够保护亚油酸/β-胡萝卜素乳液不被氧化。N-咖啡酰-L-酪氨酸甲酯和N-肉桂酰-L-多巴烷基酯在大量脂质中是有效的抗氧化剂,在乳液中是中等程度的保护剂。