Effect of platinum (II) complexes of 4-methoxy- and 4-chlorobenzoic acid hydrazides on Saccharomyces cerevisiae.

This study reports the anti-yeast effect of the 4-methoxybenzoic acid hydrazide (pmbah), 4-chlorobenzoic acid hydrazide (pcbah) and their Pt(II) complexes: cis- [PtL2X2] and cis- [PtL(NH3)Cl2] where L is either pcbah or pmbah and X is Cl, Br or I. MICs of the 4- substituted analogues (20,000-625 microM) are much lower than those of the previously reported benzoic acid hydrazide and 3-methoxybenzoic acid hydrazide. Complex formation results in significant increase of potency which may be due to a change in the mechanism of action, but the MIC (> 400-50 microM) and the IC50 (> 400-1 microM) values show that higher activity of the ligands in the free state does not result in enhanced complex activity. Differences in the potency of iodo-, chloro- and bromo complexes suggest MIC and IC50 values may be in correlation with the stability of the complex, rather than with the activity of the free ligands. Osmotically unstable mutants were more susceptible to the compounds than their parent strains, but differences among the parent strains, but differences among the parent strains were greater.