Gold(I) Analogues of a Platinum-Acridine Antitumor Agent Are Only Moderately Cytotoxic but Show Potent Activity against Mycobacterium tuberculosis

Cationic gold(I) complexes containing 1-[2-(acridin-9-ylamino)ethyl]-1,3-dimethylthiourea (1), [AuL(1)](n+) (where L is Cl-, Br-, SCN-, PEt3, PPh3, or 1), derived from a class of analogous platinum(II) antitumor agents, have been synthesized. Unlike platinum, gold does not form permanent adducts with DNA, and its complexes are 2 orders of magnitude less cytotoxic in non-small-cell lung cancer cells than the most active platinum-based agent. Instead, several gold analogues show submicromolar and selective anti microbial activity against Mycobacterium tuberculosis.