Quantum-chemical, NMR, FT IR, and ESI MS studies of complexes of colchicine with Zn(II)

Wojciech Jankowski,Piotr Barczyński,Marcin Hoffmann,Joanna Kurek

doi:10.1007/s00894-017-3306-z

Wojciech Jankowski, Piotr Barczyński + Show 2 more

Open Access

https://doi.org/10.1007/s00894-017-3306-z

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Abstract

Colchicine is a tropolone alkaloid from Colchicinum autumnale. It shows antifibrotic, antimitotic, and anti-inflammatory activities, and is used to treat gout and Mediterranean fever. In this work, complexes of colchicine with zinc(II) nitrate were synthesized and investigated using DFT, 1H and 13C NMR, FT IR, and ESI MS. The counterpoise-corrected and uncorrected interaction energies of these complexes were calculated. We also calculated their 1H, 13C NMR, and IR spectra and compared them with the corresponding experimentally obtained data. According to the ESI MS mass spectra, colchicine forms stable complexes with zinc(II) nitrate that have various stoichiometries: 2:1, 1:1:1, and 2:1:1 with respect to colchichine, Zn(II), and nitrate ion. All of the complexes were investigated using the quantum theory of atoms in molecules (QTAIM). The calculated and the measured spectra showed differences before and after the complexation process. Calculated electron densities and bond critical points indicated the presence of bonds between the ligands and the central cation in the investigated complexes that satisfied the quantum theory of atoms in molecules.Graphical DFT, NMR, FT IR, ESI MS, QTAIM and puckering studies of complexes of colchicine with Zn(II).

Highlights

Colchicine (Fig. 1) is a tropolone alkaloid from Colchicum autumnale
We reported the coordination of colchicine to iodides and perchlorates with monovalent metal ions
Three signals were observed in the ESI mass spectra obtained after complexation, which were assigned to colchicine–Zn(II) and colchicine–Zn(II)– NO3 complexes

Summary

Introduction

Colchicine (Fig. 1) is a tropolone alkaloid from Colchicum autumnale It naturally occurs as a neutral molecule; it does not form salts because of its very low basicity. Zinc is responsible for a number of different functions in the human body because it is associated with various biomolecules (for example carbonic anhydrase, thermolysin, 5-aminolevulinate dehydratase) [12, 13] It is the second most abundant metal (after iron) in the human body; it is essential for growth and development and plays important roles in various biological systems [14]. Colchicine can form stable complexes with zinc cations in human body fluids following the administration of colchicine as a drug during antigout therapy (i.e., patients take pills in which the active substance is colchicine). This fact prompted us to synthesize and examine complexes of colchicine with zinc(II) nitrate experimentally and computationally to find out if colchicine is likely to interact with the Zn(II) cation in the human body

Experimental methods

Results and discussion

Conclusions

Compliance with ethical standards