Chemistry, Alpha-glucosidase and Radical Scavenging Properties of Uranyl(VI) Hydrazide Complexes.

Background: Antioxidant, anti-inflammatory, antiviral and antitumoral activities among others are essential characteristics in the development of novel therapeutic compounds. Acid hydrazides can form complexation with certain metal ions that positively enhance these biological characteristics. Objective: Five new complexes of uranium with hydrazide ligands were synthesized at room temperature. Methods: The characterization was done by spectroscopic methods (ESI-Mass, IR, H-1-NMR, C-13-NMR), CHN analysis and conductivity measurements. Metal complexes along with their respective ligands were further screened for their antioxidant (DPPH, superoxide and nitric oxide free radicals) properties and enzyme inhibition (alpha-glucosidase) activities. Results: Elemental and spectral data indicate octahedral geometry around uranyl (UO22+) species. Magnetic moments indicate the diamagnetic nature of uranyl(VI) ion in the complex in solid state. IC50 values showed potential antioxidant behavior of uranyl complexes demonstrating interesting structure-activity relationships. In general, hydrazide ligands were not active against superoxide and nitric oxide radicals while varying degree of results were observed against DPPH radical whereas all uranyl-complexes showed promising radical scavenging activities against all of them. Promising inhibitory potential was displayed by UO2+2 hydrazide complexes against aglucosidases whereas free hydrazide ligands were inactive. Conclusion: Structure function relationship demonstrates that the nature of ligand, position of substituent, electronic and steric effects are significant factors affecting the radical scavenging and enzyme inhibition activities of the compounds.