title: Phenolic acid amides of phenolic benzylamines against UVA-induced oxidative stress in skin.
abstract: UVA-radiation is suspected to be a main cause for extrinsic skin ageing in humans. Recent studies showed that topically administered molecular antioxidants are able to protect skin against UVA-generated oxidative stress. Therefore, new phenolic acid amides of phenolic benzylamines were synthesized as potential antioxidants by reaction of (if necessary protected) N-succinimidylesters of ferulic acid, sinapic acid, caffeic acid, 3-(4-hydroxy-3-methoxyphenyl)propanoic acid, 3-(3,4-dihydroxyphenyl)propanoic acid, 2-(4-hydroxy-3-methoxyphenyl)acetic acid and 2-(3,4-dihydroxyphenyl) acetic acid with different phenolic benzylamines in moderate to good yields. The radical scavenging activities of the compounds were determined by the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay and by a superoxide radical anion trapping assay. Antioxidant activities in bulk lipids were tested by accelerated peroxidation with or without test compounds performed in the Rancimat apparatus. Stripped soybean oil and the skin sebum component squalene were used as lipids. The synthesized compounds were found to be efficient radical scavengers and antioxidants, especially the hydroxyphenylacetic amides and the hydroxydihydrocinnamic acid amides of polyhydroxybenzylamines, which are superior to the standards alpha-tocopherol and l-ascorbic acid. A topically applied 0.1% 1,3-butyleneglycol solution of N-(3,4-dihydroxybenzyl)-2-(4-hydroxy-3-methoxyphenyl)acetic acid amide 19 inhibits the UVA-induced sebum peroxidation in human skin significantly, by 39%.
authors.affiliation: Haarmann & Reimer GmbH, Research and Development Fragrances/Aroma Chemicals and Cosmetic Ingredients, PO Box 1253, D-37601 Holzminden, Germany.
authors.forename: J P
authors.initials: JP
authors.lastname: Ley