Image-Based In Vitro Screening Reveals the Trypanostatic Activity of Hydroxymethylnitrofurazone against Trypanosoma cruzi.

Hydroxymethylnitrofurazone (NFOH) is a therapeutic candidate for Chagas disease (CD). It has negligible hepatotoxicity in a murine model compared to the front-line drug benznidazole (BZN). Here, using Trypanosoma cruzi strains that express bioluminescent and/or fluorescent reporter proteins, we further investigated the in vitro and in vivo activity of NFOH to define whether the compound is trypanocidal or trypanostatic. The in vitro activity was assessed by exploiting the fluorescent reporter strain using wash-out assays and real-time microscopy. For animal experimentation, BALB/c mice were inoculated with the bioluminescent reporter strain and assessed by highly sensitive in vivo and ex vivo imaging. Cyclophosphamide treatment was used to promote parasite relapse in the chronic stage of infection. Our data show that NFOH acts by a trypanostatic mechanism, and that it is more active than BZN in vitro against the infectious trypomastigote form of Trypanosoma cruzi. We also found that it is more effective at curing experimental infections in the chronic stage, compared with the acute stage, a feature that it shares with BZN. Therefore, given its reduced toxicity, enhanced anti-trypomastigote activity, and curative properties, NFOH can be considered as a potential therapeutic option for Chagas disease, perhaps in combination with other trypanocidal agents.

Hydroxymethylnitrofurazone treatment in indeterminate form of chronic Chagas disease: Reduced intensity of tissue parasitism and inflammation-A histopathological study.

Hydroxymethylnitrofurazone (NFOH) is a nitrofurazone prodrug effective in vivo during acute infections, and it has less hepatotoxicity effect than the standard drug benznidazole (BZN) which has been used during short- and long-term treatment. In the present study, we induced the indeterminate form of Chagas disease in mice with a Y strain of Trypanosoma cruzi and analysed the histopathological data about the effects of NFOH and BZN on different tissues, including the heart, skeletal muscle, liver, kidney, colon, spleen and brain. After infection, BALB/c mice were treated with NFOH (150 mg/kg) and BZN (60 mg/kg) for 60 days and then submitted to immunosuppression using dexamethasone (5 mg/kg) for 14 days. Two trained analysts, as part of a blind evaluation, examined the results using serial sections of 3 mm diameter in two different moments. The results showed reactivation of the disease only in the infected nontreated group (POS). After treatment, amastigote nests were found in the heart, colon, liver and skeletal muscle in the POS group and in the heart and liver of the BZN group. Interestingly, amastigote nests were not found in the NFOH and NEG groups. The histopathological analysis showed fewer tissue lesions and parasite infiltrates in the NFOH group when compared with the BZN and POS groups. We have not observed any increase in the levels of hepatocellular injury biomarkers (AST/ALT) in the NFOH group. These in vivo studies show the potential for NFOH as an effective and safe compound useful as an anti-T. cruzi agent.

Hydroxymethylnitrofurazone lymphatic uptake with nanostructured lipid carrier after oral administration in rats.

Background: Leishmaniasis, caused by the protozoan Leishmania sp., infects phagocyte cells present in lymphatic organs. This study demonstrates the influence of nanostructured lipid carrier-loaded hydroxymethylnitrofurazone (NLC-NFOH) on lymphatic uptake using a chylomicron-blocking flow model in rats. Method: Lymphatic uptake of NFOH was assessed 1 h after oral administration of dimethyl sulfoxide with NFOH or NLC-NFOH with and without cycloheximide pretreatment. Result: Dimethyl sulfoxide with NFOH and NLC-NFOH showed NFOH serum concentrations of 0.0316 and 0.0291 µg/ml, respectively. After chylomicron blocking, NFOH was not detected. Conclusion: Despite log P below 5, NFOH was successfully taken up by the lymphatic system. Long-chain fatty acids and particle size might be main factors in these findings. NLC-NFOH is a promising and convenient platform for treating leishmaniasis via oral administration.

Pharmacokinetics of hydroxymethylnitrofurazone, a promising new prodrug for Chagas' disease treatment.

Hydroxymethylnitrofurazone (NFOH) is a trypanocidal prodrug of nitrofurazone (NF), devoid of mutagenic toxicity. The purpose of this work was to study the chemical conversion of NFOH into NF in sodium acetate buffer (pH 1.2 and 7.4) and in human plasma and to determine preclinical pharmacokinetic parameters in rats. At pH 1.2, the NFOH was totally transformed into NF, the parent drug, after 48 h, while at pH 7.4, after the same period, the hydrolysis rate was 20%. In human plasma, 50% of NFOH was hydrolyzed after 24 h. In the investigation of kinetic disposition, the concentration of drug in serum versus time curve was used to calculate the pharmacokinetic parameters after a single-dose regimen. NFOH showed a time to maximum concentration of drug in serum (Tmax) as 1 h, suggesting faster absorption than NF (4 h). The most important results observed were the volume of distribution (V) of NFOH through the tissues, which showed a rate that is 20-fold higher (337.5 liters/kg of body weight) than that of NF (17.64 liters/kg), and the concentration of NF obtained by in vivo metabolism of NFOH, which was about four times lower (maximum concentration of drug in serum [Cmax] = 0.83 µg/ml; area under the concentration-time curve from 0 to 12 h [AUC0-12] = 5.683 µg/ml · h) than observed for administered NF (Cmax = 2.78 µg/ml; AUC0-12 = 54.49 µg/ml · h). These findings can explain the superior activity and lower toxicity of the prodrug NFOH in relation to its parent drug and confirm NFOH as a promising anti-Chagas' disease drug candidate.

[3, 4- dinitro-furazan-based oxidation furazan acute and subchronic toxicity studies].

OBJECTIVE: To study the 3, 4- dinitro-furazan-based oxidation furazan (DNTF) of sub-acute toxicity and chronic toxicity, to determine the acute toxicity classification DNTF, the nature of toxic effects and major target organ for the development provide the basis for occupational exposure limits. METHODS: ( 1) Acute toxicity: The oral gavage method once infected, symptoms of poisoning of animals observed to calculate the LD50DNTF and 95% confidence limits. ( 2) sub-chronic experiment: selection of 96 healthy SD rats were randomly divided into four groups, doses of 25, 56.2, 125 mg/kg and the negative control group, Exposure for ninety days,five days a week, once a day, The rats were killed at end of Exposure, heart, liver, spleen, lung, kidney, brain,testis, uterus were taken to observe the pathological changes. RESULTS: ( 1) Acute oral toxicity test results indicate that DNTF rat oral LD50 greater than 5000 mg/kg, DNTF mice treated by oral LD50 4589 mg/kg, 95%confidence limit for the 4026-5230 mg/kg, Acute toxicity grade level is low toxicity compounds. (2) Sub-chronic toxicity experiment, the high-dose male rats, high, medium and low-dose group female rats weight gain than the negative control group, compared with the control group, the difference was statistically significant (P<0.05).125 mg/kg of serum alanine aminotransferase, aspartate aminotransferase was significantly higher. 125 mg/kg dose groups, liver, kidney, lung, testicular factor was significantly higher. Liver, kidney, lung histological examination showed obvious morphological changes. CONCLUSION: Acute toxicity grade DNTF low toxicity level compounds, target organ toxicity of liver, kidney and lung.

Quinofuracins F - I, new quinofuracin derivatives produced by Staphylotrichum boninense PF1444.

Four new quinofuracins F - I were isolated from the culture broth of Staphylotrichum boninense PF1444. The structures of quinofuracins F - I were elucidated by extensive spectroscopic analysis. These quinofuracins induced tumor suppressor protein p53-dependent cell death in human glioblastoma LNZTA3 cells.

Hydroxymethylnitrofurazone is active in a murine model of Chagas' disease.

The addition of a hydroxymethyl group to the antimicrobial drug nitrofurazone generated hydroxymethylnitrofurazone (NFOH), which had reduced toxicity when its activity against Trypanosoma cruzi was tested in a murine model of Chagas' disease. Four groups of 12 Swiss female mice each received 150 mg of body weight/kg/day of NFOH, 150 mg/kg/day of nitrofurazone (parental compound), 60 mg/kg/day of benznidazole (BZL), or the solvent as a placebo. Treatments were administered orally once a day 6 days a week until the completion of 60 doses. NFOH was as effective as BZL in keeping direct parasitemia at undetectable levels, and PCR results were negative. No histopathological lesions were seen 180 days after completion of the treatments, a time when the levels of anti-T. cruzi antibodies were very low in mice treated with either NFOH or BZL. Nitrofurazone was highly toxic, which led to an overall rate of mortality of 75% and necessitated interruption of the treatment. In contrast, the group treated with its hydroxymethyl derivative, NFOH, displayed the lowest mortality (16%), followed by the BZL (33%) and placebo (66%) groups. The findings of histopathological studies were consistent with these results, with the placebo group showing the most severe parasite infiltrates in skeletal muscle and heart tissue and the NFOH group showing the lowest. The present evidence suggests that NFOH is a promising anti-T. cruzi agent.

Cruzain inhibition by hydroxymethylnitrofurazone and nitrofurazone: investigation of a new target in Trypanosoma cruzi.

Nitrofurazone (NF) and its derivative, hydroxymethylnitrofurazone (NFOH), have presented antichagasic activity. NFOH has higher activity and lower mutagenicity. The aim of this work was to assess whether NF and its derivative NFOH would also be inhibitors of cruzain, besides their trypanothione reductase inhibitory activity. In vitro cruzain inhibition tests were performed for both compounds, and the 50% inhibitory concentration (IC50) for NF and NFOH presented values of 22.83 +/- 1.2 microM and 10.55 +/- 0.81 microM, respectively. AM1 semi-empirical molecular modeling studies were performed to understand the activity of the compounds, corroborating the observed cruzain inhibitory activity.

A new medium-throughput screening design approach for the development of hydroxymethylnitrofurazone (NFOH) nanostructured lipid carrier for treating leishmaniasis.

Hydroxymethilnitrofurazone (NFOH) is a nitrofurazone derivative and has potential use in treating leishmaniasis. However, due to low water solubility and bioavailability, NFOH has failed in in vivo tests. Nanostructured lipid carrier (NLC) is an alternative to overcome these limitations by improving pharmacokinetics and modifying drug delivery. This work is focused on developing a novel NFOH-loaded NLC (NLC-NFOH) using a D-optimal mixture statistical design and high-pressure homogenization, for oral administration to treat leishmaniasis. The optimized NLC-NFOH consisted of Mygliol® 840, Gelucire® 50/13, and Precirol® ATO 5 as lipids. These lipids were selected using a rapid methodology Technobis Crystal 16 T M, microscopy, and DSC. Different tools for selecting lipids provided relevant scientific knowledge for the development of the NLC. NLC-NFOH presented a z-average of 198.6 ±â€¯5.4 nm, PDI of 0.11 ±â€¯0.01, and zeta potential of -13.7 ±â€¯0.7 mV. A preliminary in vivo assay was performed by oral administration of NLC-NFOH (2.8 mg/kg) in one healthy male Wistar rat (341 g) by gavage. Blood from the carotid vein was collected, and the sample was analyzed by HPLC. The plasma concentration of NFOH after 5 h of oral administration was 0.22 µg/mL. This same concentration was previously found using free NFOH in the DMSO solution (200 mg/kg), which is an almost 100-fold higher dose. This study allowed a design space development approach of the first NLC-NFOH with the potential to treat leishmaniasis orally.

Uncovering the action of ethanol controlled crystallization of 3,4-bis(3-nitrofurazan-4-yl)furoxan crystal: A molecular dynamics study.

A computational strategy in consideration of attachment energy, temperature, solubility and supersaturation unravels details of the solvent effect on the crystal morphology. The crystal morphologies were predicted by the advanced screw dislocation growth model. This research sheds much light on the crystal growth mechanisms with the example of 3,4-bis(3-nitrofurazan-4-yl)furoxan (DNTF) in ethanol. The solvation model based on the experiment situation was established into periodic supercell. Molecular dynamics simulation was performed for obtaining the adsorption energy at the equilibrium state of the interface layer. The growth characteristics of relevant growth faces are introduced. At the same time, a periodic bond chains analysis can be applied to the existence and evolution of crystal growth units. The prediction results are in remarkable agreement with the experimental results. We found that crystal morphology of DNTF is composed of (002), (111), (111¯) and (101) faces in ethanol. As the saturation temperature rises, the (101) face becomes smaller and eventually disappears.

Study of the interaction between hydroxymethylnitrofurazone and 2-hydroxypropyl-beta-cyclodextrin.

Chagas disease is a serious health problem in Latin America. Hidroxymethylnitrofurazone (NFOH) is a nitrofurazone prodrug more active than nitrofurazone against Trypanosoma cruzi. However, NFOH presents low aqueous solubility, high photodecomposition and high toxicity. The present work is focused on the characterization of an inclusion complex of NFOH in 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD). The complexation with HP-beta-CD was investigated using reversed-phase liquid chromatography, solubility isotherms and nuclear magnetic resonance. The retention behavior was analyzed on a reversed-phase C(18) column, using acetonitrile-water (20/80, v/v) as the mobile phase, in which HP-beta-CD was incorporated as a mobile phase additive. The decrease in the retention times with increasing concentrations of HP-beta-CD enables the determination of the apparent stability constant of the complex (K=6.2+/-0.3M(-1)) by HPLC. The solubility isotherm was studied and the value for the apparent stability constant (K=7.9+/-0.2M(-1)) was calculated. The application of continuous variation method indicated the presence of a complex with 1:1 NFOH:HP-beta-CD stoichiometry. The photostability study showed that the formation of an inclusion complex had a destabilizing effect on the photodecomposition of NFOH when compared to that of the "free" molecule in solution. The mobility investigation (by NMR longitudinal relaxation time) gives information about the complexation of NFOH with HP-beta-CD. In preliminary toxicity studies, cell viability tests revealed that inclusion complexes were able to decrease the toxic effect (p<0.01) caused by NFOH.

Rapid test for the evaluation of the activity of the prodrug hydroxymethylnitrofurazone in the processing of Trypanosoma cruzi messenger RNAs.

No fully effective treatment has been developed since the discovery of Chagas' disease by Carlos Chagas in 1909. Since drug-resistant Trypanosoma cruzi strains are occurring and the current therapy is effectiveness in the acute phase but with various adverse side effects, more studies are needed to characterize the susceptibility of T. cruzi to new drugs. Many natural and/or synthetic substances showing trypanocidal activity have been used, even though they are not likely to be turned into clinically approved drugs. Originally, drug screening was performed using natural products, with only limited knowledge of the molecular mechanism involved in the development of diseases. Trans-splicing, which is unusual RNA processing reaction and occurs in nematodes and trypanosomes, implies the processing of polycistronic transcription units into individual mRNAs; a short transcript spliced leader (SL RNA) is trans-spliced to the acceptor pre-mRNA, giving origin to the mature mRNA. In the present study, permeable cells of T. cruzi epimastigote forms (Y, BOL and NCS strains) were treated to evaluate the interference of two drugs (hydroxymethylnitrofurazone - NFOH-121 and nitrofurazone) in the trans-splicing reaction using silver-stained PAGE analysis. Both drugs induced a significant reduction in RNA processing at concentrations from 5 to 12.5 microM. These data agreed with the biological findings, since the number of parasites decreased, especially with NFOH-121. This proposed methodology allows a rapid and cost-effective screening strategy for detecting drug interference in the trans-splicing mechanism of T. cruzi.

Targeting Leishmania amazonensis amastigotes through macrophage internalisation of a hydroxymethylnitrofurazone nanostructured polymeric system.

Dextran-coated poly (n-butyl cyanoacrylate) nanoparticles (PBCA-NPs) were prepared and were evaluated for enhanced delivery of a promising anti-Leishmania drug candidate, hydroxymethylnitrofurazone (NFOH), to phagocytic cells. Currently available chemotherapy for leishmaniasis, such as pentavalent antimonials, presents low safety and efficacy. Furthermore, widespread drug resistance in leishmaniasis is rapidly emerging. To overcome these drawbacks, the use of nanosized delivery systems can reduce systemic drug toxicity and increase the drug concentration in infected macrophages, therefore improving treatment of leishmaniasis. PBCA-NPs containing NFOH (PBCA-NFOH-NPs) were prepared by an anionic emulsion polymerisation method. The z-average and polydispersity index (PDI) were determined by photon correlation spectroscopy, the zeta potential by microelectrophoresis and the entrapment efficiency by HPLC. Cytotoxicity was determined using macrophages from BALB/c mice. Efficacy tests were performed using Leishmania amazonensis promastigotes and amastigotes. The z-average of PBCA-NFOH-NPs was 151.5 ± 61.97 nm, with a PDI of 0.104 ± 0.01, a zeta potential of -10.1 ± 6.49 mV and an entrapment efficiency of 64.47 ± 0.43%. Efficacy in amastigotes revealed IC50 values of 0.33 µM and 31.2 µM for the nanostructured and free NFOH, respectively (95-fold increase). The cytotoxicity study indicated low toxicity of the PBCA-NFOH-NPs to macrophages. The selectivity index was 370.6, which is 49-fold higher than free NFOH (7.6). Such findings indicated that improved efficacy could be due to NP internalisation following site-specific drug delivery and reactivation of immune protective reactions by the NP components. Thus, PBCA-NFOH-NPs have the potential to significantly improve the treatment of leishmaniasis, with reduced systemic side effects.

Thermochemical properties and non-isothermal decomposition reaction kinetics of 3,4-dinitrofurazanfuroxan (DNTF).

The constant-volume combustion energy, DeltacU (DNTF, s, 298.15K) and kinetic behavior of the exothermic decomposition reaction of the title compound (DNTF) are determined by a precise rotating bomb calorimeter and DSC, respectively. Its standard enthalpy of combustion, DeltacHmtheta (DNTF, s, 298.15K), standard enthalpy of formation, DeltacHmtheta (DNTF, s, 298.15K) and kinetic parameters of the major exothermic decomposition reaction in a temperature-programmed mode [the apparent activation energy (Ea) and pre-exponential factor (A)] are calculated. The values of DeltacU (DNTF, s, 298.15K), DeltacHmtheta (DNTF, s, 298.15K), and DeltacHmtheta (DNTF, s, 298.15K) of DNTF are -9733.96 +/- 8.59 Jg(-1), -3018.29 +/- 2.68 kJ mol(-1), and 657.23 +/- 2.70 kJ mol(-1), respectively. The kinetic model function in integral form and the value of E(a) and A of the major exothermic decomposition reaction of DNTF are 1-(1-alpha)1/3, 177.03 kJ mol(-1) and 10(13.68)s(-1), respectively. The critical temperature of thermal explosion of DNTF is 240.6 degrees C.

Hepatotoxicity in mice of a novel anti-parasite drug candidate hydroxymethylnitrofurazone: a comparison with Benznidazole.

BACKGROUND: Treatment of Chagas disease, caused by Trypanosoma cruzi, relies on nifurtimox and benznidazole (BZL), which present side effects in adult patients, and natural resistance in some parasite strains. Hydroxymethylnitrofurazone (NFOH) is a new drug candidate with demonstrated trypanocidal activity; however, its safety is not known. METHODS: HepG2 cells dose response to NFOH and BZL (5-100 µM) was assessed by measurement of ROS, DNA damage and survival. Swiss mice were treated with NFOH or BZL for short-term (ST, 21 d) or long-term (LT, 60 d) periods. Sera levels of cellular injury markers, liver inflammatory and oxidative stress, and fibrotic remodeling were monitored. RESULTS: HepG2 cells exhibited mild stress, evidenced by increased ROS and DNA damage, in response to NFOH, while BZL at 100 µM concentration induced >33% cell death in 24 h. In mice, NFOH ST treatment resulted in mild-to-no increase in the liver injury biomarkers (GOT, GPT), and liver levels of inflammatory (myeloperoxidase, TNF-α), oxidative (lipid peroxides) and nitrosative (3-nitrotyrosine) stress. These stress responses in NFOH LT treated mice were normalized to control levels. BZL-treated mice exhibited a >5-fold increase in GOT, GPT and TNF-α (LT) and a 20-40% increase in liver levels of MPO activity (ST and LT) in comparison with NFOH-treated mice. The liver inflammatory infiltrate was noted in the order of BZL>vehicle≥NFOH and BZL>NFOH≥vehicle, respectively, after ST and LT treatments. Liver fibrotic remodeling, identified after ST treatment, was in the order of BZL>vehicle>NFOH; lipid deposits, indicative of mitochondrial dysfunction and in the order of NFOH>vehicle>BZL were evidenced after LT treatment. CONCLUSIONS: NFOH induces mild ST hepatotoxicity that is normalized during LT treatment in mice. Our results suggest that additional studies to determine the efficacy and toxicity of NFOH are warranted.

Pharmacokinetics of hydroxymethylnitrofurazone and its parent drug nitrofurazone in rabbits.

The prodrug hydroximethylnitrofurazone (NFOH) presents antichagasic activity with greatly reduced toxicity compared to its drug matrix nitrofurazone (NF). Besides these new characteristics, the prodrug was more active against the parasite T. cruzi amastigotes. These advantages make the prodrug a possible therapeutic alternative for the treatment of both acute and the chronic phase of Chagas disease. However, the knowledge of pharmacokinetic profile is crucial to evaluate the feasibility of a new drug. In this study, our objective was to evaluate the in vivo formation of NF from the NFOH single administration and to evaluate its pharmacokinetic profile and compared it to NF administration. A bioanalytical method to determine the NF and NFOH by LCMS/MS was developed and validated to perform these investigations. Male albino rabbits (n=15) received NF intravenously and orally in doses of 6.35 and 63.5 mg / kg respectively, and NFOH, 80.5 mg / kg orally. The serial blood samples were processed and analyzed by mass spectrometry. The system operated in positive and negative modes for the analites determination, under elution of the mobile phase 50:50 water: methanol. The administration of NFOH allowed the calculation of pharmacokinetic parameters for the prodrug, and the NF obtained from NFOH administration. Using the pharmacokinetic profile obtained from the NF i.v. administration, the oral bioavailability of NF from the administered prodrug was obtained (60.1%) and, as a key parameter in a prodrug administration, should be considered in future studies. The i.v. and oral administrations of NF differ in the constant of elimination (0.04 vs 0.002) and elimination half-life (17.32 min vs 276.09 min) due to the low solubility of the drug that hinders the formation of molecular dispersions in the digestory tract. Still, there was observed no statistical differences were observed between the pharmacokinetic parameters of orally administered NF and NF obtained from NFOH. The calculated area under the curve (AUC 0-∞) showed that the exposure to the parental drug was fairly the same (844.79 vs 566.44) for NF and NF obtained from the prodrug administration. The tendency to higher NF's mean residence time (MRT) as observed in the prodrug administration (956.1 min vs 496.3 min) guarantees longer time for the action of the drug and it allows the expansion of the administration intervals. These findings, added with the beneficial characteristics of the prodrug encourage new efficacy tests towards the clinical use of NFOH.

Molecular modeling study on the disassembly of dendrimers designed as potential antichagasic and antileishmanial prodrugs.

A molecular modeling study was carried out to investigate the most likely enzymatic disassembly mechanism of dendrimers that were designed as potential antichagasic and antileishmanial prodrugs. The models contained myo-inositol (core), L-malic acid (spacer), and active agents such as 3-hydroxyflavone, quercetin, and hydroxymethylnitrofurazone (NFOH). A theoretical approach that considered one, two, or three branches has already been performed and reported by our research group; the work described herein focused on four (models A and B), five, or six branches, and considered their physicochemical properties, such as spatial hindrance, electrostatic potential mapping, and the lowest unoccupied molecular orbital energy (E(LUMO)). The findings suggest that the carbonyl group next to the myo-inositol is the most promising ester breaking point.

Oxidative metabolites of 5-nitrofurans.

We synthesized the 4-hydroxy derivatives of nitrofurazone, furazolidone and nitrofurantoin. Then we dosed rats orally with these antibiotics and isolated the intensely yellow, polar metabolites from their urine. A comparison of the ultraviolet and nuclear magnetic resonance spectra of these metabolites with the corresponding synthetic derivatives confirmed that the metabolites are 4-hydroxynitrofurazone, 4-hydroxyfurazolidone and 4-hydroxynitrofurantoin.

Synthesis and in vitro evaluation of potential antichagasic hydroxymethylnitrofurazone (NFOH-121): a new nitrofurazone prodrug.

The synthesis of mutual prodrugs of nitrofurazone with primaquine, using specific and nonspecific spacer groups, has been previously attempted seeking selective antichagasic agents. The intermediate reaction product, hydroxymethylnitrofurazone (NFOH-121), was isolated and tested in LLC-MK(2) culture cells infected with trypomastigotes forms of Trypanosoma cruzi showing higher trypanocidal activity than nitrofurazone and benznidazol in all stages. The mutagenicity tests showed that the prodrug was less toxic than the parent drug. Degradation assays were carried out in pH 1.2 and 7.4.

Trypanosoma cruzi: establishment of permeable cells for RNA processing analysis with drugs.

Pre-mRNA maturation in trypanosomatids occurs through a process called trans-splicing which involves excision of introns and union of exons in two independent transcripts. For the first time, we present the standardization of Trypanosoma cruzi permeable cells (Y strain) as a model for trans-splicing study of mRNAs in trypanosomes, following by RNase protection reaction, which localizes the SL exon and intron. This trans-splicing reaction in vitro was also used to analyze the influence of NFOH-121, a nitrofurazone-derivative, on this mechanism. The results suggested that the prodrug affects the RNA processing in these parasites, but the trans-splicing reaction still occurred.