A silver complex with tryptophan: Synthesis, structural characterization, DFT studies and antibacterial and antitumor assays in vitro

The synthesis, spectroscopic characterization and biological assays of a new silver(I) complex with l-tryptophan (TRP) are presented. Elemental and thermal analyses and ESI-QTOF mass spectrometric measurements of the solid compound suggest the composition AgC11H11N2O2. Infrared and solid-state NMR analyses indicate coordination of TRP to Ag(I) ion through the nitrogen of the NH2 group and also through the oxygen of carboxylate group. Theoretical (DFT) calculations permit proposing an optimized geometry for the complex. Antibacterial assays indicated that the Ag-TRP complex is effective against Staphylococcus aureus and Enterococcus faecalis (Gram-positive), and Pseudomonas aeruginosa and Escherichia coli (Gram-negative) bacterial strains. The complex was also cytotoxic against Panc-1 (human pancreatic carcinoma) and SK-Mel 103 (human melanoma) cells.

► A silver(I) complex with tryptophan.
► IR, ESI-QTOF-MS and NMR studies permitted proposing nitrogen and oxygen coordination.
► DFT studies supported the proposed structure for the complex.
► The compound shows antibacterial activities against Gram-negative and -positive bacteria.
► The complex was cytotoxic in vitro against human pancreatic carcinoma and melanoma cells.