Antimicrobial Activity of Water-Soluble Silver Complexes Bearing C-Scorpionate Ligands

• Main Authors: Abdallah G. Mahmoud (Author), Sílvia A. Sousa (Author), M. Fátima C. Guedes da Silva (Author), Luísa M. D. R. S. Martins (Author), Jorge H. Leitão (Author)
• Format: Book
• Published: MDPI AG, 2024-07-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.

Summary

The novel hydrosoluble silver coordination polymer [Ag(NO₃)(μ-1κ<i>N</i>;2<i>κN</i>',<i>N</i>"-TPM^OH)]_n (<b>1</b>) (TPM^OH = tris(1<i>H</i>-pyrazol-1-yl)ethanol) was obtained and characterized. While single crystal X-ray diffraction analysis of compound <b>1</b> disclosed an infinite 1D helical chain structure in the solid state, NMR analysis in polar solvents confirmed the mononuclear nature of compound <b>1</b> in solution. Compound <b>1</b> and the analogue [Ag(μ-1κ<i>N</i>;2<i>κN</i>',<i>N</i>"-TPMS)]_n (<b>2</b>) (TPMS = tris(1<i>H</i>-pyrazol-1-yl)methane sulfonate) were evaluated with regard to their antimicrobial activities towards the Gram-negative <i>Escherichia coli</i>, <i>Pseudomonas aeruginosa</i>, and <i>Burkholderia contaminans</i>, the Gram-positive <i>Staphylococcus aureus</i>, and the fungal species <i>Candida albicans</i> and <i>Candida glabrata</i>. Compound <b>1</b> exhibited minimal inhibitory concentration (MIC) values ranging from 2 to 7.7 µg/mL towards the tested Gram-negative bacteria, 18 µg/mL towards the Gram-positive <i>S. aureus</i>, and 15 and 31 µg/mL towards <i>C. albicans</i> and <i>C. glabrata</i>, respectively. Compound <b>2</b> was less effective towards the tested bacteria, with MIC values ranging from 15 to 19.6 µg/mL towards the Gram-negative bacteria and 51 µg/mL towards <i>S. aureus</i>; however, it was more effective against <i>C. albicans</i> and <i>C. glabrata</i>, with MIC values of about 6 µg/mL towards these fungal species. The toxicity of compounds <b>1</b> and <b>2</b> was assessed by evaluating the survival of the <i>Caenorhabditis elegans</i> model organism to concentrations of up to 100 µg/mL. The value of 50% lethality (LD₅₀) could only be estimated as 73.2 µg/mL for compound <b>1</b> at 72 h, otherwise LD₅₀ was >100 µg/mL for both compounds <b>1</b> and <b>2</b>. These results indicate compounds <b>1</b> and <b>2</b> as novel silver complexes with interesting antimicrobial properties towards bacterial and fungal pathogens.

Item Description

10.3390/antibiotics13070647
2079-6382