In vitro tripanocidal effect of 1,8-dioxooctahydroxanthenes (xanthenodiones) and tetraketones and improvement of cardiac parameters in vivo.

OBJECTIVE: Trypanosoma cruzi infection affects millions of people worldwide, and the drugs available for its treatment have limited efficacy. 1,8-Dioxooctahydroxanthenes and tetraketones are compounds with important biological applications. The aim of this study was to assess the trypanocidal and inflammatory activities of nine 1,8-dioxooctahydroxanthenes (1-9) and three tetraketones (10-12). METHODS AND RESULTS: By in vitro killing assay, three compounds were able to eliminate CL TdTomato expressing strain of T. cruzi, 9 (IC50=30.65µM), 10 (IC50=14.11µM), and 11 (IC50=26.43µM). However, only 9 was not toxic to Vero cells. Next, to evaluate the in vivo antitrypanosomal and immunological efficacy of 9, Swiss mice were infected with the Y and CL strains of T. cruzi and treated for 10 days with 50mg/kg of 9. This compound reduced the cardiac inflammatory infiltration in animals infected with both strains. Rank's ligand (RankL), CCL2, and interferon (IFN)-γ were measured in the cardiac tissue homogenate of the Y-strain-infected animals, and no interference of 9 was observed. However, compound 9 increased the RankL and interleukin (IL)-10 levels in CL-infected mice. No hepatic and renal toxicity was observed. CONCLUSION: Our findings showed that 1,8-dioxooctahydroxanthene has antiparasitic effect and ameliorates the cardiac inflammatory parameters related to T. cruzi infection.

Combination therapy with benznidazole and doxycycline shows no additive effect to monotherapy with benznidazole in mice infected with the VL-10 strain of the Trypanosoma cruzi.

BACKGROUND: Chagas heart disease is the most important clinical manifestation of Trypanosoma cruzi infection. Pharmacological therapies have been proposed aiming to reduce inflammatory response and cardiac damage in infected hosts. In this study, we investigated the use of doxycycline (Dox), in a sub-antimicrobial dose, in monotherapy and in combination with benznidazole (Bz) during the acute phase of infection with the VL-10 strain of T. cruzi, evaluating the therapeutic effect during the acute and chronic phases of the infection. METHODS AND RESULTS: C57BL/6 mice were treated for 20 days with Dox (30 mg/kg), Bz (100 mg/kg), or both drugs in combination starting 9 days after infection. Parasitemia was measured during the acute phase and the animals were monitored for 12 months, after which echocardiography analysis was performed. Blood samples were obtained from euthanized mice for CCL2, CCL5, IL-10 analysis, and cardiac fragments were collected for histopathological evaluation. Dox treatment did not ameliorate parasitological/inflammatory parameters but reduced the cardiac collagen neoformation (CN) in 35%. In contrast, Bz administration reduced parasitemia, plasma levels of CCL2 and CCL5, and cardiac infiltration during acute infection, and reduced the level of IL-10 and CN (95%) at 12 months. Dox was unable to improve ejection fraction, while Bz treatment ameliorated the ejection fraction. No additive effect was observed in combination therapy. CONCLUSION: Dox monotherapy is not effective in the acute or chronic phases of experimental cardiomyopathy induced by the VL-10 strain of T. cruzi. Furthermore, combination therapy with Dox does not potentiate the effects of Bz monotherapy.

Baccharis trimera protects against ethanol induced hepatotoxicity in vitro and in vivo.

ETHNOPHARMACOLOGICAL RELEVANCE: Baccharis trimera has been traditionally used in Brazil to treat liver diseases. AIM OF THE STUDY: To evaluate the protective effect of Baccharis trimera in an ethanol induced hepatotoxicity model. MATERIALS AND METHODS: The antioxidant capacity was evaluated in vitro by the ability to scavenged the DPPH radical, by the quantification of ROS, NO and the transcription factor Nrf2. Hepatotoxicity was induced in animals by administration of absolute ethanol for 2 days (acute) or with ethanol diluted for 28 days (chronic). The biochemical parameters of hepatic function (ALT and AST), renal function (urea and creatinine) and lipid profile (total cholesterol, triglycerides and HDL) were evaluated. In addition to antioxidant defense (SOD, catalase, glutathione), oxidative damage markers (TBARS and carbonylated protein), MMP-2 activity and liver histology. RESULTS: Baccharis trimera promoted a decrease in ROS and NO, and at low concentrations promoted increased transcription of Nrf2. In the acute experiment it promoted increase of HDL, in the activity of SOD and GPx, besides diminishing TBARS and microesteatosis. Already in the chronic experiment B. trimera improved the hepatic and renal profile, decreased triglycerides and MMP-2 activity, in addition to diminishing microesteatosis. CONCLUSION: We believe that B. trimera action is possibly more associated with direct neutralizing effects or inhibition of reactive species production pathways rather than the modulation of the antioxidant enzymes activity. Thus it is possible to infer that the biological effects triggered by adaptive responses are complex and multifactorial depending on the dose, the time and the compounds used.