Insulin-enhancing activity of a dinuclear vanadium complex: 5-chloro-salicylaldhyde ethylenediamine oxovanadium(V) and its permeability and cytotoxicity

A new insulin-enhancing oxovanadium complex 5-chloro-salicylaldhyde ethylenediamine oxovanadium (V) ([V2O2(μ-O)2L2]) has been synthesized. The complex was characterized by a variety of physical methods, including X-ray crystallography. The X-ray diffraction analysis show a dinuclear complex of two six-coordinate vanadium centers doubly bridged by the oxygen atoms of the Schiff base ligand with a V2O2 diamond core. The complex was administered intragastrically to STZ-diabetic rats for 2 weeks. The biological activity results show that the complex at the dose of 10.0 and 20.0 mg V kg− 1, could significantly decrease the blood glucose level and ameliorate impaired glucose tolerance in STZ-diabetic rats. That results suggested that the complex exerts an antidiabetic effect in STZ-diabetic rats. Furthermore, the complex ([V2O2(μ-O)2L2]) had permeability above 10− 5 cm/s. The experimental results suggested that the vanadium complex permeates via a passive diffusion mechanism. It was also suggested the complex with salen-type ligands has good lipophilic properties and better oral administration. The cytotoxicity of the complex ([V2O2(μ-O)2L2]) on Caco-2 cells was measured by a decrease of cell viability using the MTT assay suggesting that the chlorine atom at C4 of complex [V2O2(μ-O)2L2] increased cytotoxicity for vanadium complexes.

Graphical abstractA new insulin-enhancing oxovanadium complex 5-chloro-salicylaldhyde ethylenediamine oxovanadium (V) ([(V2O2(μ-O)2L)2]) was administered intragastrically to STZ-diabetic rats for 2 weeks. The biological activity results show that the complex at the dose of 10.0 and 20.0 mg V kg− 1, could significantly decrease the blood glucose level and ameliorate impaired glucose tolerance in STZ-diabetic rats. That results suggested that the complex exerts an antidiabetic effect in STZ-diabetic rats. Significantly, our results presented here show that the complex [(V2O2(μ-O)2L)2] with chloro substituent did lower diabetic hyperglycemia under dosing conditions.Figure optionsDownload full-size imageDownload as PowerPoint slide