In vitro and In vivo Biological Activity of Two Aryloxy-naphthoquinones in Mice Infected with Trypanosoma cruzi Strains.

Background: Chagas disease, a condition caused by Trypanosoma cruzi, is an endemic disease in Latin American countries that affects approximately eight million people worldwide. It is a continuing public health problem. As nifurtimox and benznidazole are the two pharmacological treatments currently used to treat it, the present research proposes new therapeutic alternatives. Previous studies conducted on naphthoquinone derivatives have found interesting trypanocidal effects on epimastigotes, with the molecules 2-phenoxy-1,4-naphthoquinone (IC₅₀= 50 nM and SI < 250) and 2-(3-nitrophenoxy)-naphthalene-1,4-dione (IC₅₀= 20 nM and SI=625) presenting the best biological activity..

Methods: The present study evaluated the efficacy of in vitro, ex vivo and in vivo models of two aryloxyquinones, 2-phenoxy-1,4-naphthoquinone (1) and 2-(3-nitrophenoxy)-naphthalene-1,4- dione (2), against two Mexican T. cruzi strains in both their epimastigote and blood Trypomastigote stage. Both compounds were evaluated against T. cruzi using a mouse model (CD1) infected with Mexican isolates of T. cruzi, nifurtimox and benznidazole used as control drugs. Finally, the cytotoxicity of the two compounds against the J774.2 mouse macrophage cell line was also determined.

Results: The in vitro and in vivo results obtained indicated that both quinones were more active than the reference drugs. Compound 1 presents in vivo activity, showing up to 40% parasite reduction after 8 h of administration, a finding which is 1.25 times more effective than the results obtained using nifurtimox.

Conclusion: These are encouraging results for proposing new naphthoquinone derivatives with potential anti-T. cruzi activity.