Biological Activity of NHC-Gold-Alkynyl Complexes Derived from 3-Hydroxyflavones.

In this paper we describe the synthesis of new -heterocyclic carbene (NHC) gold(I) derivatives with flavone-derived ligands with a propargyl ether group. The compounds were screened for their antimicrobial and anticancer activities, showing greater activity against bacteria than against colon cancer cells (Caco-2). Complexes [Au(L2b)(IMe)] () and [Au(L2b)(IPr)] () were found to be active against both Gram-positive and Gram-negative strains. The mechanism of action of was evaluated by measurement of thioredoxin reductase (TrxR) and dihydrofolate reductase (DHFR) activity, besides scanning electron microscopy (SEM). Inhibition of the enzyme thioredoxin reductase is not observed in either or Caco-2 cells; however, DHFR activity is compromised after incubation of cells with complex . Moreover, loss of structural integrity and change in bacterial shape is observed in the images obtained from scanning electron microscopy (SEM) after treatment cells with complex .