Synthesis, characterisation and cytotoxic properties of N-heterocyclic carbene silver(I) complexes

A benzimidazolium salt bearing hydroxyethyl group, 1a and a new series of zwitterionic sulphonated benzimidazolium salts, 1b-e were reacted with Ag2O to produce Ag(I)-N-heterocyclic carbene (NHC) complexes, 2a-e respectively. Synthesised silver(I)-N-heterocyclic carbene complexes were fully characterised by H-1 and C-13 NMR, elemental analysis and HRMS spectroscopic methods. Anti-cancer potential of both NHC salts and complexes were tested and the IC50 values of these NHC salts and complexes were determined by a proliferation BrdU enzyme-linked immunosorbent assay (ELISA) against HeLa (Human cervix carcinoma), HT29 (human adenocarcinoma) and L929 (mouse fibroblast) cell lines. The IC50 values are in the range of 11 +/- 1-126 +/- 3 mu M show that all new Ag(I)-NHC complexes especially complex 2b demonstrated remarkable cytotoxic activity against HeLa, HT29 and L929 while 1a-e NHC salts are found to be inactive against HeLa, HT29 and L929. Also, the high IC50 value of complex 2b against L929 cells can be interpreted high selectivity against healthy cells. This complex has been highlighted as new types of metalodrug. (C) 2018 Elsevier B.V. All rights reserved.