In vitro and in vivo antiproliferative and trypanocidal activities of ruthenium NO donors.
OBJECTIVE
Many compounds liberating NO (NO donors) have been used as therapeutic agents. Here we test two ruthenium nitrosyls, which release NO when activated by biological reducing agents, for their effects in vitro and in vivo against Trypanosoma cruzi, the agent responsible for the American trypanosomiasis (Chagas' disease).


METHODS
Ruthenium NO donors were incubated with a partially drug-resistant strain of T. cruzi and the anti-proliferative and trypanocidal activities evaluated. In a mouse model of acute Chagas' disease, trypanocidal activity was evaluated by measuring parasitemia, survival rate of infected mice and elimination of amastigotes in myocardial tissue.


RESULTS
In vitro, the observed anti-proliferative and trypanocidal activities of trans-[Ru(NO)(NH(3))(4)isn](BF(4))(3) and trans-[Ru(NO)(NH(3))(4)imN](BF(4))(3) were due to NO liberated upon reduction of these nitrosyls. Ru(NO)isn had a lower IC(50 epi) (67 microM) than the NO donor, sodium nitroprusside (IC(50 epi)=244 microM) and Ru(NO)imN (IC(50 try)=52 microM) was more potent than gentian violet (IC(50 try)=536 microM), currently used in the treatment of blood. Both ruthenium nitrosyls eliminated, in vivo, extracellular as well as intracellular forms of T. cruzi in the bloodstream and myocardial tissue and allowed survival of up to 80% of infected mice at a dose (100 nmol kg(-1) day(-1)) much lower than the optimal dose for benznidazole (385 micromol kg(-1) day(-1)).


CONCLUSIONS
Our data strongly suggest that NO liberated is responsible for the anti-proliferative and trypanocidal activities of the ruthenium NO donors and that these compounds are promising leads for novel and effective anti-parasitic drugs.
Silva
J J N
JJ
Departamento de Química e Física Molecular, Instituto de Química de São Carlos-Universidade de São Paulo (USP), São Carlos, SP, Brazil.
Osakabe
A L
AL
Pavanelli
W R
WR
Silva
J S
JS
Franco
D W
DW
D000818:Animals; D014355:Chagas Disease / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005840:Gentian Violet / Q000494:pharmacology; D006321:Heart / Q000187:drug effects* / Q000469:parasitology; D020128:Inhibitory Concentration 50; D051379:Mice; D009206:Myocardium / Q000473:pathology; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D009599:Nitroprusside / Q000494:pharmacology; D018512:Parasitemia / Q000188:drug therapy* / Q000378:metabolism / Q000469:parasitology / Q000473:pathology; D021261:Parasitic Sensitivity Tests; D017975:Ruthenium Compounds / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D014344:Trypanocidal Agents / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D014349:Trypanosoma cruzi / Q000187:drug effects* / Q000254:growth & development
D020030:Nitric Oxide Donors; D017975:Ruthenium Compounds; D014344:Trypanocidal Agents; D009599:Nitroprusside; D009569:Nitric Oxide; D005840:Gentian Violet