Speciation study and biological activity of copper (II) complexes with picolinic and 6-methylpicolinic acid with different components of blood serum of low molecular mass in KNO3 1.0 mol.L-1 at 25 °C

In the present work, the chemical speciation of ternary complexes of copper (II) with picolinic acid and 6-methylpicolinic acid and different ligands, such as, components of the blood plasma of low molecular mass (lactic acid, oxalic acid, citric acid, and phosphoric acid) were studied by measurements of emf(H) in KNO3 1.00 molL- 1. Potentiometric studies showed a predilection towards the formation of ternary species in solution, except for the copper (II)-picolinate-phosphate systems. The biological activity of the binary and ternary complexes isolated in situ, against reactive oxygen species was studied showing a concentration-dependent effect due to a possible mechanism of electron transfer. Finally, for the complexes Cu(Pic)2 and for the ligands were studied the ligand-receptor interaction on a PI3k of human origin by molecular docking, showing that, by themselves, the ligands are not capable of interacting with the active site of the enzyme. The metallic center is fundamental to generate reversible electrostatic interactions, that can be key to the indirect hypoglycemic effect exhibited by the Cu(Pic)2 complex reported in the literature.

Automated summary

The study found that in solution, copper (II) tends to form ternary complexes with picolinic acid, 6-methylpicolinic acid, and low molecular mass blood plasma components. The biological activity of the isolated binary and ternary complexes exhibited a concentration-dependent effect. Molecular docking studies revealed that the metallic center is essential for generating reversible electrostatic interactions, which may be key to the indirect hypoglycemic effect exhibited by the Cu(Pic)2 complex.