RESUMO
BACKGROUND: Protein glycation refers to the spontaneous reaction of reducing sugars with proteins and the subsequent formation of stable advanced glycation end products (AGEs). Glycation is linked with oxidative stress, and this association is called "glycoxidation". Glycoxidation alters the protein structure and function and causes tissue aging, as seen in human skin. Therefore, research on substances inhibiting glycoxidation appears to be crucial in the prevention of skin aging. With this aim, several plant extracts have been screened for antiglycation activity, and the results of the best candidates are presented in this article. METHODS: Glycation was studied on human skin proteins (collagen, elastin, and albumin) and on a model of reconstructed skin. Oxidative stress has been addressed by testing the copper-induced low-density lipoprotein oxidation, ultraviolet irradiation of glycated dermis, and carbonyl activation of human dermal fibroblasts. A clinical test evaluated the extent of oxidative stress induced by ultraviolet A irradiation. RESULTS: Among the tested products, several plant extracts have decreased the glycation effects on skin proteins collagen, elastin, and albumin. In addition, a plant extract has significantly inhibited the different forms of oxidative stress associated with protein glycation. CONCLUSIONS: We have demonstrated that plant extracts can relieve the deleterious effects of glycation on human skin. Moreover, a plant extract rich in antioxidant molecules has also significantly preserved the human skin from glycoxidation attacks.
Assuntos
Estresse Oxidativo , Pele/metabolismo , Albuminas/química , Albuminas/metabolismo , Colágeno/química , Colágeno/metabolismo , Cobre/química , Cobre/farmacologia , Elastina/química , Elastina/metabolismo , Fibroblastos/citologia , Glicosilação/efeitos dos fármacos , Glicosilação/efeitos da radiação , Glioxal/farmacologia , Humanos , Lipoproteínas LDL/metabolismo , Manilkara/química , Manilkara/metabolismo , Modelos Biológicos , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/efeitos da radiação , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Raios UltravioletaRESUMO
2, 3-Di-ω-halo- as well as 2, 3-di-ω-toluenesulfonamide-alkylated glucopyranoside derivatives were prepared. Their condensation with α,ω-bis-toluenesulfonamide components under varying Richman-Atkins conditions with alkali carbonate in DMF led to carbohydrate-linked aza-macrocycles displaying 14-, 17-, 18-, 21-, 24-, and 25-membered ring structures. Isomeric aza-macrocylic coronands of 20- as well as 30-membered ring size containing two saccharides could be obtained employing Richman-Atkins condensations of two functionalized sugar building units.