TABLE 1.

Efficacies of dinuclear thiolate-bridged arene ruthenium complexes against T. gondii beta-galactosidase-expressing tachyzoites, host cell (HFF) cytotoxicity, and physicochemical data^a

Complex	IC50 (nM) for T. gondii beta-gal	IC50 (μM) for HFFs	LogP for RSH group
1	34 ± 4	800	2.98 ± 0.28
2	62 ± 10	>1,000	4.21 ± 0.29
3	540 ± 60	ND	2.38 ± 0.32
4	130 ± 20	ND	2.83 ± 0.42
5	120 ± 20	ND	1.68 ± 0.29
9	1.2 ± 0.5	5,129	ND

^aChloride salts of the corresponding thiols of complexes 1 to 5 and 9 were used for all experiments. For the determination of efficacies, confluent HFF monolayers grown in a 96-well plate were treated with the complexes at various concentrations and were infected with T. gondii beta-gal tachyzoites (10³ per well). After 3 days, beta-galactosidase activity or host cell viability was determined, and IC₅₀s were calculated as described in the text. The logP values correspond to the values that were calculated for the thiol RSH groups (17). ND, not done.