Antimicrobial and anticancer activity of tetrahedral, chelated, diphosphine silver(I) complexes: comparison with copper and gold.

Tetrahedral, bischelated Ag(I) diphosphine complexes [Ag(P-P)2]NO3, where P-P is Ph2P(CH2)2PPh2 (dppe), Et2P(CH2)2PPh2 (depe), and cis-Ph2P(CH = CH)PPh2 (dppey), are potently cytotoxic to B16 melanoma cells in vitro (IC50 4 microM) and exhibit good activity against ip P388 leukemia in mice. The complex [Ag(dppe)2]NO3 is active against M5076 reticulum cell sarcoma. The antibacterial and antifungal activities of Ag(I) diphosphine and related Cu(I) and Au(I) complexes were assessed. The complexes [Au(dppey)2]Cl, [Au(dppp)2]Cl and (CuCl)2(dppe)3 show modest activity against three of the 12 bacterial strains tested, but all complexes exhibit antifungal activity against three strains of C. albicans in a "defined" medium, [Ag(depe)2]NO3 and [Au(dppp)2]Cl having comparable activity to fungizone. Antifungal activity of the complexes is reduced in Sabouraud's broth medium, and lost altogether for the Ag(I) complexes. Reactions of some of the Ag(I) complexes with glutathione and blood plasma were studied by 31P NMR.