Coordination to copper(II) strongly enhances the in vitro antimicrobial activity of pyridine-derived N(4)-tolyl thiosemicarbazones
摘要:
Five copper(II) complexes with N(4)-ortho, N(4)-meta and N(4)-para-tolyl thiosemicarbazones derived from 2-formyl and 2-acetylpyridine were obtained and thoroughly characterized. The crystal structure of N(4)-meta-tolyl-2-acetylpyridine thiosemicarbazone (H2Ac4mT) was determined, as well as that of its copper(II) complex [Cu(2Ac4mT)Cl], which contains an anionic ligand and a chloride in the coordination sphere of the metal. The in vitro antimicrobial activities of all thiosemicarbazones and their copper(II) complexes were tested against Salmonella typhinturium and Candida albicans. Upon coordination a substantial decrease in the minimum inhibitory concentration, from 225 to 1478 mu mol L-1 for the thiosernicarbazones to 5-30 mu mol L-1 for the complexes was observe against the growth of Salmonella typhimurium and from 0.7-26 to 0.3-7 mu mol L-1 against the growth of C albicans, suggesting that complexation to copper(II) could be an interesting strategy of dose reduction. (c) 2007 Elsevier Ltd. All rights reserved.