Biological Evaluation Of Hydroxyl-substituted Schiff-bases Containing Ferrocenyl Moieties And Preparation Of Thiol-responsive Fluorescent Nanomicelles

We synthesized three new hydroxyl-substituted Schiff-bases containing ferrocenyl moieties (compounds1-3). Their structures were characterized by1H-NMR,13C-NMR, ESI-MS and IR. Their antioxidant activity were evaluated by free radical scavenging and hemolysis inhibition assays. Compound4without ferrocenyl group and victamine E were used as control. We also determined the interaction between compounds1-4and human serum albumin (HSA), as well as the cytotoxicity of compounds with WST-1method. The results show that compound1can efficiently scavenge ABTS and DPPH free radicals and inhibit erythrocyte hemolysis, which reveal their high antioxidant activity. Each of compounds1-4can bind to HSA with a high binding site and insert into its hydrophobic domain. And this interaction between compound1and HSA slows down the hydrolysis of compound1. Compared with compounds2-4, compound1exhibit the highest cytotoxicity. The cyclic voltammetric data and lipophilicity studies show that the excellent biological activities of compound1contribute to the presence of both ferrocenyl and o-dihydroxyl groups. Ferrocenyl moiety plays dual functions in compound1, i.e., increasing the lipophilicity and lowering the redox potentials of hydroxyl groups in the compound. Thus, compound1containing both ferrocenyl and o-dihydroxyl groups is a potential antioxidant along with anticancer activity.A new amphiphilic compound14were synthesized and characterized by1H-NMR,13C-NMR, ESI-MS and IR. Compound14can self-assemble into micelles in water. Their structures and dimensions were determined by TEM and dynamic light scattering. The response of micelles to thiol was also evaluated with fluorescence spectrophotometer and dynamic light scattering. The results show that most of the micelles are nanoparticles with diameter about14.4nm. A few micelles exhibit nanorods structure, with cross sectional diameter7.4nm and length100-400nm. The micelles solution is clear with fluorescent emission peak at473nm. After DL-Dithiothreitol (DTT) addition the dimensions of micelles gradually enlarge and finally the micelles decompose with kelly sediment precipitated. The fluorescent emission peak shifts to530nm. The micelles response to DTT within the physiologic pH range (6.0-8.5). Observation and determination can be carried out after addition of DTT30min. Micelles response to DTT more obviously than to cysteine (Cys), and with no significant response to glutathione (GSH) and victamine C. Thus, this kind of micelles can realize the aim of responsive decomposition and visible monitor, which will make them new kind of nanomaterial.