Zinc(II) Complexes with Amino Acids for Potential Use in Dermatology: Synthesis, Crystal Structures, and Antibacterial Activity

Michał Abendrot; Lilianna Chęcińska; Joachim Kusz; Katarzyna Lisowska; Katarzyna Zawadzka; Aleksandra Felczak; Urszula Kalinowska-Lis

doi:10.3390/molecules25040951

Zinc(II) Complexes with Amino Acids for Potential Use in Dermatology: Synthesis, Crystal Structures, and Antibacterial Activity

Molecules. 2020 Feb 20;25(4):951. doi: 10.3390/molecules25040951.

Authors

Michał Abendrot¹, Lilianna Chęcińska², Joachim Kusz³, Katarzyna Lisowska⁴, Katarzyna Zawadzka⁴, Aleksandra Felczak⁴, Urszula Kalinowska-Lis¹

Affiliations

¹ Department of Cosmetic Raw Materials Chemistry, Faculty of Pharmacy, Medical University of Lodz, Muszyńskiego 1, 90-151 Łódź, Poland.
² Faculty of Chemistry, University of Lodz, Pomorska 163/165, 90-236 Łódź, Poland.
³ Institute of Physics, University of Silesia, 75 Pułku Piechoty 1, 41-500 Chorzów, Poland.
⁴ Department of Industrial Microbiology and Biotechnology, Faculty of Biology and Environmental Protection, University of Lodz, 12/16 Banacha Street, 90-237 Łódź, Poland.

Abstract

The multifunctional profile of Zn²⁺ has influenced its great popularity in various pharmaceutical, food, and cosmetic products. Despite the use of different inorganic and organic zinc derivatives, the search for new zinc-containing compounds with a safer skin profile still remains an open issue. The present paper describes the synthesis, structural characterization, and antibacterial activity of zinc(II) complexes with proteinogenic amino acids as potential candidates for dermatological treatments. The obtained complexes are of the general formula [Zn(AA)₂], where AA represents an amino acid (L-Glu, Gly, L-His, L-Pro, L-Met, and L-Trp). Their synthesis was designed in such a way that the final bis(aminoacidate) zinc(II) complexes did not contain any counter-ions such as Cl^-, NO₃^-, or SO₄^2- that can cause some skin irritations. The chemical structure and composition of the compounds were identified by ¹H NMR spectroscopy and elemental analysis, and four were also characterized by single-crystal X-ray diffraction. The Hirshfeld surface analysis for the Zn²⁺ metallic center helped to determine its coordination number and geometry for each complex. Finally, the antibacterial properties of the complexes were determined with respect to three Gram-positive strains, viz. Staphylococcus aureus ATCC 6538, Staphylococcus epidermidis ATCC 12228, and Streptococcus pyogenes ATCC 19615, and two Gram-negative bacteria, viz. Escherichia coli ATCC 25992 and Pseudomonas aeruginosa ATCC 27853, and were compared with the activity of zinc 2-pirrolidone 5-carboxylate (ZnPCA), commonly applied in dermatology. It was found that the Zn(II) complexes with methionine and glycine exhibited a higher antibacterial activity than the tested standard, and the antimicrobial properties of complex with Trp were satisfactory. The results of the antimicrobial activity examination allow us to postulate that the obtained zinc complexes might become new active substances for use in dermatological products.

Keywords: Hirshfeld surface analysis; antibacterial activity; crystal structures; proteinogenic amino acids; zinc(II) complexes.

MeSH terms

Amino Acids / chemistry*
Anti-Bacterial Agents* / chemical synthesis
Anti-Bacterial Agents* / chemistry
Anti-Bacterial Agents* / pharmacology
Bacteria / growth & development*
Coordination Complexes* / chemical synthesis
Coordination Complexes* / chemistry
Coordination Complexes* / pharmacology
Microbial Sensitivity Tests
Molecular Structure
Zinc / chemistry*

Substances

Amino Acids
Anti-Bacterial Agents
Coordination Complexes
Zinc