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1.
Parasitology ; 151(5): 506-513, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38533610

ABSTRACT

Leishmania is a trypanosomatid parasite that causes skin lesions in its cutaneous form. Current therapies rely on old and expensive drugs, against which the parasites have acquired considerable resistance. Trypanosomatids are unable to synthesize purines relying on salvaging from the host, and nucleoside analogues have emerged as attractive antiparasitic drug candidates. 4-Methyl-7-ß-D-ribofuranosyl-7H-pyrrolo[2,3-d]pyrimidine (CL5564), an analogue of tubercidin in which the amine has been replaced by a methyl group, demonstrates activity against Trypanosoma cruzi and Leishmania infantum. Herein, we investigated its in vitro and in vivo activity against L. amazonensis. CL5564 was 6.5-fold (P = 0.0002) more potent than milteforan™ (ML) against intracellular forms in peritoneal mouse macrophages, and highly selective, while combination with ML gave an additive effect. These results stimulated us to study the activity of CL5564 in mouse model of cutaneous Leishmania infection. BALB/c female and male mice infected by L. amazonensis treated with CL5564 (10 mg kg−1, intralesional route for five days) presented a >93% reduction of paw lesion size likely ML given orally at 40 mg kg−1, while the combination (10 + 40 mg kg−1 of CL5564 and ML, respectively) caused >96% reduction. The qPCR confirmed the suppression of parasite load, but only the combination approach reached 66% of parasitological cure. These results support additional studies with nucleoside derivatives.


Subject(s)
Disease Models, Animal , Leishmania mexicana , Leishmaniasis, Cutaneous , Mice, Inbred BALB C , Animals , Leishmaniasis, Cutaneous/drug therapy , Leishmaniasis, Cutaneous/parasitology , Mice , Female , Male , Leishmania mexicana/drug effects , Tubercidin/pharmacology , Tubercidin/analogs & derivatives , Antiprotozoal Agents/pharmacology , Antiprotozoal Agents/therapeutic use , Antiprotozoal Agents/administration & dosage , Macrophages, Peritoneal/parasitology , Macrophages, Peritoneal/drug effects , Leishmania/drug effects
2.
Exp Parasitol ; 262: 108787, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38759776

ABSTRACT

New affordable drugs are needed for the treatment of infection with the protozoan parasite Trypanosoma cruzi responsible for the Chagas disease (CD). Only two old drugs are currently available, nifurtimox and benznidazole (Bz) but they exhibit unwanted side effects and display a weak activity in the late chronic phase of the disease. In this context, we evaluated the activity of a series of aryl-pyrazolone derivatives against T cruzi, using both bloodstream trypomastigote and intracellular amastigote forms of the parasite. The test compounds originate from a series of anticancer agents targeting the immune checkpoint ligand PD-L1 and bear an analogy with known anti-trypanosomal pyrazolones. A first group of 6 phenyl-pyrazolones was tested, revealing the activity of a single pyridyl-pyrazolone derivative. Then a second group of 8 compounds with a common pyridyl-pyrazolone core was evaluated. The in vitro testing process led to the identification of two non-cytotoxic and highly potent molecules against the intracellular form of T. cruzi, with an activity comparable to Bz. Moreover, one compound revealed an activity largely superior to that of Bz against bloodstream trypomastigotes, while being non-cytotoxic (selectivity index >1000). Unfortunately, the compound showed little activity in vivo, most likely due to its very limited plasma stability. However, the study opens novel perspectives for the design of new anti-trypanosomal products and the mechanism of action of the compounds is discussed.


Subject(s)
Chagas Disease , Pyrazolones , Trypanocidal Agents , Trypanosoma cruzi , Trypanosoma cruzi/drug effects , Pyrazolones/pharmacology , Pyrazolones/chemistry , Trypanocidal Agents/pharmacology , Trypanocidal Agents/chemistry , Animals , Mice , Chagas Disease/drug therapy , Chagas Disease/parasitology , Pyridines/pharmacology , Pyridines/chemistry , Inhibitory Concentration 50 , Nitroimidazoles/pharmacology , Nitroimidazoles/chemistry
3.
Mem Inst Oswaldo Cruz ; 119: e240057, 2024.
Article in English | MEDLINE | ID: mdl-38958341

ABSTRACT

Chagas disease is a tropical neglected disease that affects millions of people worldwide, still demanding a more effective and safer therapy, especially in its chronic phase which lacks a treatment that promotes substantial parasitological cure. The technical note of Romanha and collaborators published in 2010 aimed establish a guideline with the set of minimum criteria and decision gates for the development of new agents against Trypanosoma cruzi with the focus on developing new antichagasic drugs. In this sense, the present review aims to update this technical note, bringing the state of the art and new advances on this topic in recent years.


Subject(s)
Chagas Disease , Disease Models, Animal , Drug Evaluation, Preclinical , Trypanocidal Agents , Trypanosoma cruzi , Chagas Disease/drug therapy , Trypanocidal Agents/pharmacology , Trypanocidal Agents/therapeutic use , Animals , Trypanosoma cruzi/drug effects , Humans , Drug Development
4.
Parasitology ; 149(4): 490-495, 2022 04.
Article in English | MEDLINE | ID: mdl-35109958

ABSTRACT

Cutaneous leishmaniasis (CL) is a spectrum of clinical manifestations characterized by severe skin ulcerations that leads to social stigma. There are limited treatment options for CL, and the available drugs are becoming less efficacious due to drug resistance. More efficacious and safer antileishmanial drugs are needed. In this study, the biological effect of seven synthetically accessible nitroaromatic compounds was evaluated in vitro against amastigotes of Leishmania amazonensis, followed by in vivo evaluation using mouse models of CL. Two compounds (6 and 7) were active against amastigotes in vitro [half-maximal effective concentration (EC50): 4.57 ± 0.08 and 9.19 ± 0.68 µm, respectively], with selectivity indexes >50, and the other compounds were not selective. In vivo, compounds 6 and 7 (10 mg kg−1, twice a day for 14 days) failed to reduce skin lesion sizes and parasite loads determined by light microscopy of lesion imprints and quantitative polymerase chain reaction. Nevertheless, the in vitro leishmanicidal efficacy sustained their use as templates for nitroimidazole-based antileishmanial drug discovery programmes focusing on analogues with more suitable properties.


Subject(s)
Antiprotozoal Agents , Leishmania mexicana , Leishmaniasis, Cutaneous , Animals , Antiprotozoal Agents/pharmacology , Antiprotozoal Agents/therapeutic use , Leishmaniasis, Cutaneous/drug therapy , Mice , Mice, Inbred BALB C , Nitro Compounds/therapeutic use
5.
Mem Inst Oswaldo Cruz ; 117: e220004, 2022.
Article in English | MEDLINE | ID: mdl-35293439

ABSTRACT

Chagas disease (CD), a neglected tropical illness caused by the protozoan Trypanosoma cruzi, affects more than 6 million people mostly in poor areas of Latin America. CD has two phases: an acute, short phase mainly oligosymptomatic followed to the chronic phase, a long-lasting stage that may trigger cardiac and/or digestive disorders and death. Only two old drugs are available and both present low efficacy in the chronic stage, display side effects and are inactive against parasite strains naturally resistant to these nitroderivatives. These shortcomings justify the search for novel therapeutic options considering the target product profile for CD that will be presently reviewed besides briefly revisiting the data on phosphodiesterase inhibitors upon T. cruzi.


Subject(s)
Chagas Disease , Trypanocidal Agents , Trypanosoma cruzi , Chagas Disease/drug therapy , Humans , Latin America , Trypanocidal Agents/pharmacology , Trypanocidal Agents/therapeutic use
6.
Int J Mol Sci ; 23(23)2022 Nov 24.
Article in English | MEDLINE | ID: mdl-36498985

ABSTRACT

Ecto-nucleoside triphosphate diphosphohydrolases (NTPDases) are enzymes located on the surface of the T. cruzi plasma membrane, which hydrolyze a wide range of tri-/-diphosphate nucleosides. In this work, we used previously developed genetically modified strains of Trypanosoma cruzi (T. cruzi), hemi-knockout (KO +/−) and overexpressing (OE) the TcNTPDase-1 gene to evaluate the parasite infectivity profile in a mouse model of acute infection (n = 6 mice per group). Our results showed significantly higher parasitemia and mortality, and lower weight in animals infected with parasites OE TcNTPDase-1, as compared to the infection with the wild type (WT) parasites. On the other hand, animals infected with (KO +/−) parasites showed no mortality during the 30-day trial and mouse weight was more similar to the non-infected (NI) animals. In addition, they had low parasitemia (45.7 times lower) when compared with parasites overexpressing TcNTPDase-1 from the hemi-knockout (OE KO +/−) group. The hearts of animals infected with the OE KO +/− and OE parasites showed significantly larger regions of cardiac inflammation than those infected with the WT parasites (p < 0.001). Only animals infected with KO +/− did not show individual electrocardiographic changes during the period of experimentation. Together, our results expand the knowledge on the role of NTPDases in T. cruzi infectivity, reenforcing the potential of this enzyme as a chemotherapy target to treat Chagas disease (CD).


Subject(s)
Chagas Disease , Trypanosoma cruzi , Mice , Animals , Chagas Disease/genetics , Chagas Disease/parasitology , Heart , Disease Models, Animal
7.
Article in English | MEDLINE | ID: mdl-33361300

ABSTRACT

The phosphodiesterase inhibitor tetrahydrophthalazinone NPD-008 was explored by phenotypic in vitro screening, target validation, and ultrastructural approaches against Trypanosoma cruzi NPD-008 displayed activity against different forms and strains of T. cruzi (50% effective concentration [EC50], 6.6 to 39.5 µM). NPD-008 increased cAMP levels of T. cruzi and its combination with benznidazole gave synergistic interaction. It was also moderately active against intracellular amastigotes of Leishmania amazonensis and Leishmania infantum, confirming a potential activity profile as an antitrypanosomatid drug candidate.


Subject(s)
Antiprotozoal Agents , Chagas Disease , Leishmania mexicana , Trypanosoma cruzi , Antiprotozoal Agents/therapeutic use , Chagas Disease/drug therapy , Humans , Phosphoric Diester Hydrolases
8.
Parasitology ; 148(1): 98-104, 2021 01.
Article in English | MEDLINE | ID: mdl-33023678

ABSTRACT

Cutaneous leishmaniasis (CL) is one of the most disregarded tropical neglected disease with the occurrence of self-limiting ulcers and triggering mucosal damage and stigmatizing scars, leading to huge public health problems and social negative impacts. Pentavalent antimonials are the first-line drug for CL treatment for over 70 years and present several drawbacks in terms of safety and efficacy. Thus, there is an urgent need to search for non-invasive, non-toxic and potent drug candidates for CL. In this sense, we have implemented a shape-based virtual screening approach and identified a set of 32 hit compounds. In vitro phenotypic screenings were conducted using these hit compounds to check their potential leishmanicidal effect towards Leishmania amazonensis (L. amazonensis). Two (Cp1 and Cp2) out of the 32 compounds revealed promising antiparasitic activities, exhibiting considerable potency against intracellular amastigotes present in peritoneal macrophages (IC50 values of 9.35 and 7.25 µm, respectively). Also, a sterile cidality profile was reached at 20 µm after 48 h of incubation, besides a reasonable selectivity (≈8), quite similarly to pentamidine, a diamidine still in use clinically for leishmaniasis. Cp1 with an oxazolo[4,5-b]pyridine scaffold and Cp2 with benzimidazole scaffold could be developed by lead optimization studies to enhance their leishmanicidal potency.


Subject(s)
Antiprotozoal Agents/pharmacology , Drug Evaluation, Preclinical , Leishmaniasis, Cutaneous/drug therapy , Macrophages, Peritoneal/parasitology , Animals , Benzimidazoles/pharmacology , Cells, Cultured , Disease Models, Animal , In Vitro Techniques , Inhibitory Concentration 50 , Leishmania/drug effects , Mice , Mice, Inbred BALB C , Oxazoles/pharmacology , Pentamidine/pharmacology , Pyridones/pharmacology
9.
Exp Parasitol ; 221: 108061, 2021 Feb.
Article in English | MEDLINE | ID: mdl-33383023

ABSTRACT

Chagas disease (CD) caused by Trypanosoma cruzi remains a serious public health problem in Latin America. The available treatment is limited to two old drugs, benznidazole (Bz) and nifurtimox, which exhibit limited efficacy and trigger side effects, justifying the search for new therapies. Also, more accurate and sensitive experimental protocols for drug discovery programs are necessary to shrink the translational gaps found among pre-clinical and clinical trials. Presently, cardiac spheroids were used to evaluate host cell cytotoxicity and anti-T.cruzi activity of benznidazole, exploring its effect on the release of inflammatory mediators. Bz presented low toxic profile on 3D matrices (LC50 > 200 µM) and high potency in vitro (EC50 = 0.99 µM) evidenced by qPCR analysis of T.cruzi-infected cardiac spheroids. Flow cytometry appraisal of inflammatory mediators released at the cellular supernatant showed increases in IL - 6 and TNF contents (≈190 and ≈ 25-fold) in parasitized spheroids as compared to uninfected cultures. Bz at 10 µM suppressed parasite load (92%) concomitantly decreasing in IL-6 (36%) and TNF (68%). Our findings corroborate the successful use of 3D cardiac matrices for in vitro identification of novel anti-parasitic agents and potential impact in host cell physiology.


Subject(s)
Nitroimidazoles/pharmacology , Trypanocidal Agents/pharmacology , Trypanosoma cruzi/drug effects , Animals , Imaging, Three-Dimensional , Mice , Microscopy, Fluorescence , Molecular Conformation , Spheroids, Cellular , Trypanosoma cruzi/growth & development
10.
Mem Inst Oswaldo Cruz ; 116: e210084, 2021.
Article in English | MEDLINE | ID: mdl-34431854

ABSTRACT

Extracts of the plant Glycyrrhiza glabra (licorice) are used in traditional medicine to treat malaria. The main active components are the saponin glycyrrhizin (GLR) and its active metabolite glycyrrhetinic acid (GA) which both display activities against Plasmodium falciparum. We have identified three main mechanisms at the origin of their anti-plasmodial activity: (i) drug-induced disorganisation of membrane lipid rafts, (ii) blockade of the alarmin protein HMGB1 and (iii) potential inhibition of the detoxifying enzyme glyoxalase 1 (GLO-1) considered as an important drug target for malaria. Our analysis shed light on the mechanism of action of GLR against P. falciparum.


Subject(s)
Glycyrrhiza , Triterpenes , Glycyrrhizic Acid/pharmacology , Plant Extracts/pharmacology , Plasmodium falciparum
11.
Article in English | MEDLINE | ID: mdl-32601163

ABSTRACT

Pyrazolones are heterocyclic compounds with interesting biological properties. Some derivatives inhibit phosphodiesterases (PDEs) and thereby increase the cellular concentration of cyclic AMP (cAMP), which plays a vital role in the control of metabolism in eukaryotic cells, including the protozoan Trypanosoma cruzi, the etiological agent of Chagas disease (CD), a major neglected tropical disease. In vitro phenotypic screening identified a 4-bromophenyl-dihydropyrazole dimer as an anti-T. cruzi hit and 17 novel pyrazolone analogues with variations on the phenyl ring were investigated in a panel of phenotypic laboratory models. Potent activity against the intracellular forms (Tulahuen and Y strains) was obtained with 50% effective concentration (EC50) values within the 0.17 to 3.3 µM range. Although most were not active against bloodstream trypomastigotes, an altered morphology and loss of infectivity were observed. Pretreatment of the mammalian host cells with pyrazolones did not interfere with infection and proliferation, showing that the drug activity was not the result of changes to host cell metabolism. The pyrazolone NPD-227 increased the intracellular cAMP levels and was able to sterilize T. cruzi-infected cell cultures. Thus, due to its high potency and selectivity in vitro, and its additive interaction with benznidazole (Bz), NPD-227 was next assessed in the acute mouse model. Oral dosing for 5 days of NPD-227 at 10 mg/kg + Bz at 10 mg/kg not only reduced parasitemia (>87%) but also protected against mortality (>83% survival), hence demonstrating superiority to the monotherapy schemes. These data support these pyrazolone molecules as potential novel therapeutic alternatives for Chagas disease.


Subject(s)
Chagas Disease , Nitroimidazoles , Pyrazolones , Trypanocidal Agents , Trypanosoma cruzi , Animals , Chagas Disease/drug therapy , Mice , Nitroimidazoles/therapeutic use , Phosphodiesterase Inhibitors/therapeutic use , Pyrazolones/pharmacology , Pyrazolones/therapeutic use , Trypanocidal Agents/pharmacology , Trypanocidal Agents/therapeutic use
12.
J Antimicrob Chemother ; 75(4): 958-967, 2020 04 01.
Article in English | MEDLINE | ID: mdl-31860098

ABSTRACT

BACKGROUND: Chagas' disease, caused by the protozoan parasite Trypanosoma cruzi, needs urgent alternative therapeutic options as the treatments currently available display severe limitations, mainly related to efficacy and toxicity. OBJECTIVES: As phosphodiesterases (PDEs) have been claimed as novel targets against T. cruzi, our aim was to evaluate the biological aspects of 12 new phthalazinone PDE inhibitors against different T. cruzi strains and parasite forms relevant for human infection. METHODS: In vitro trypanocidal activity of the inhibitors was assessed alone and in combination with benznidazole. Their effects on parasite ultrastructural and cAMP levels were determined. PDE mRNA levels from the different T. cruzi forms were measured by quantitative reverse transcription PCR. RESULTS: Five TcrPDEs were found to be expressed in all parasite stages. Four compounds displayed strong effects against intracellular amastigotes. Against bloodstream trypomastigotes (BTs), three were at least as potent as benznidazole. In vitro combination therapy with one of the most active inhibitors on both parasite forms (NPD-040) plus benznidazole demonstrated a quite synergistic profile (xΣ FICI = 0.58) against intracellular amastigotes but no interaction (xΣ FICI = 1.27) when BTs were assayed. BTs treated with NPD-040 presented disrupted Golgi apparatus, a swollen flagellar pocket and signs of autophagy. cAMP measurements of untreated parasites showed that amastigotes have higher ability to efflux this second messenger than BTs. NPD-001 and NPD-040 increase the intracellular cAMP content in both BTs and amastigotes, which is also released into the extracellular milieu. CONCLUSIONS: The findings demonstrate the potential of PDE inhibitors as anti-T. cruzi drug candidates.


Subject(s)
Chagas Disease , Trypanocidal Agents , Trypanosoma cruzi , Chagas Disease/drug therapy , Humans , Phosphodiesterase Inhibitors/pharmacology , Phosphodiesterase Inhibitors/therapeutic use , Trypanocidal Agents/pharmacology , Trypanocidal Agents/therapeutic use
13.
Parasitology ; 147(11): 1216-1228, 2020 09.
Article in English | MEDLINE | ID: mdl-32530391

ABSTRACT

In previous studies, we have identified several families of 5-nitroindazole derivatives as promising antichagasic prototypes. Among them, 1-(2-aminoethyl)-2-benzyl-5-nitro-1,2-dihydro-3H-indazol-3-one, (hydrochloride) and 1-(2-acetoxyethyl)-2-benzyl-5-nitro-1,2-dihydro-3H-indazol-3-one (compounds 16 and 24, respectively) have recently shown outstanding activity in vitro over the drug-sensitive Trypanosoma cruzi CL strain (DTU TcVI). Here, we explored the activity of these derivatives against the moderately drug-resistant Y strain (DTU TcII), in vitro and in vivo. The outcomes confirmed their activity over replicative forms, showing IC50 values of 0.49 (16) and 5.75 µm (24) towards epimastigotes, 0.41 (16) and 1.17 µm (24) against intracellular amastigotes. These results, supported by the lack of toxicity on cardiac cells, led to better selectivities than benznidazole (BZ). Otherwise, they were not as active as BZ in vitro against the non-replicative form of the parasite, i.e. bloodstream trypomastigotes. In vivo, acute toxicity assays revealed the absence of toxic events when administered to mice. Moreover, different therapeutic schemes pointed to their capability for decreasing the parasitaemia of T. cruzi Y acute infected mice, reaching up to 60% of reduction at the peak day as monotherapy (16), 79.24 and 91.11% when 16 and 24 were co-administered with BZ. These combined therapies had also a positive impact over the mortality, yielding survivals of 83.33 and 66.67%, respectively, while untreated animals reached a cumulative mortality of 100%. These findings confirm the 5-nitroindazole scaffold as a putative prototype for developing novel drugs potentially applicable to the treatment of Chagas disease and introduce their suitability to act in combination with the reference drug.


Subject(s)
Indazoles , Trypanosoma cruzi/drug effects , Animals , Cell Line , Chagas Disease/drug therapy , Chagas Disease/parasitology , Drug Resistance , Drug Therapy, Combination , Humans , Indazoles/pharmacology , Indazoles/toxicity , Mice , Nitroimidazoles/pharmacology , Parasitemia/drug therapy , Trypanocidal Agents/pharmacology , Trypanocidal Agents/toxicity
14.
Article in English | MEDLINE | ID: mdl-30670432

ABSTRACT

More than 100 years after being first described, Chagas disease remains endemic in 21 Latin American countries and has spread to other continents. Indeed, this disease, which is caused by the protozoan parasite Trypanosoma cruzi, is no longer just a problem for the American continents but has become a global health threat. Current therapies, i.e., nifurtimox and benznidazole (Bz), are far from being adequate, due to their undesirable effects and their lack of efficacy in the chronic phases of the disease. In this work, we present an in-depth phenotypic evaluation in T. cruzi of a new class of imidazole compounds, which were discovered in a previous phenotypic screen against different trypanosomatids and were designed as potential inhibitors of cAMP phosphodiesterases (PDEs). The confirmation of several activities similar or superior to that of Bz prompted a synthesis program of hit optimization and extended structure-activity relationship aimed at improving drug-like properties such as aqueous solubility, which resulted in additional hits with 50% inhibitory concentration (IC50) values similar to that of Bz. The cellular effects of one representative hit, compound 9, on bloodstream trypomastigotes were further investigated. Transmission electron microscopy revealed cellular changes, after just 2 h of incubation with the IC50 concentration, that were consistent with induced autophagy and osmotic stress, mechanisms previously linked to cAMP signaling. Compound 9 induced highly significant increases in both cellular and medium cAMP levels, confirming that inhibition of T. cruzi PDE(s) is part of its mechanism of action. The potent and selective activity of this imidazole-based PDE inhibitor class against T. cruzi constitutes a successful repurposing of research into inhibitors of mammalian PDEs.


Subject(s)
3',5'-Cyclic-AMP Phosphodiesterases/antagonists & inhibitors , Antiparasitic Agents/pharmacology , Chagas Disease/drug therapy , Imidazoles/pharmacology , Trypanosoma cruzi/drug effects , Animals , Autophagy/drug effects , Cells, Cultured , Drug Discovery , Imidazoles/chemical synthesis , Mice , Parasitic Sensitivity Tests , Structure-Activity Relationship
16.
Parasitology ; 141(3): 367-73, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24553079

ABSTRACT

Chagas disease (CD) is caused by the intracellular protozoan parasite Trypanosoma cruzi and affects more than 10 million people in poor areas of Latin America. There is an urgent need for alternative drugs with better safety, broader efficacy, lower costs and shorter time of administration. Thus the biological activity of viniconazole, a chloroaryl-substituted imidazole was investigated using in vitro and in vivo screening models of T. cruzi infection. Ultrastructural findings demonstrated that the most frequent cellular damage was associated with plasma membrane (blebs and shedding events), Golgi (swelling aspects) and the appearance of large numbers of vacuoles suggesting an autophagic process. Our data demonstrated that although this compound is effective against bloodstream and intracellular forms (16 and 24 µ m, respectively) in vitro, it does not present in vivo efficacy. Due to the urgent need for novel agents against T. cruzi, the screening of natural and synthetic products must be further supported with the aim of finding more selective and affordable drugs for CD.


Subject(s)
Chagas Disease/drug therapy , Imidazoles/pharmacology , Trypanocidal Agents/pharmacology , Trypanosoma cruzi/drug effects , Animals , Chagas Disease/parasitology , Disease Models, Animal , Dose-Response Relationship, Drug , Humans , Imidazoles/chemistry , Imidazoles/therapeutic use , Male , Mice , Parasitemia/drug therapy , Parasitemia/parasitology , Parasitic Sensitivity Tests , Primary Cell Culture , Trypanocidal Agents/chemistry , Trypanocidal Agents/therapeutic use , Trypanosoma cruzi/ultrastructure
17.
Antimicrob Agents Chemother ; 57(11): 5307-14, 2013 Nov.
Article in English | MEDLINE | ID: mdl-23939901

ABSTRACT

In vitro and in vivo activities against Trypanosoma cruzi were evaluated for two sesquiterpene lactones: psilostachyin A and cynaropicrin. Cynaropicrin had previously been shown to potently inhibit African trypanosomes in vivo, and psilostachyin A had been reported to show in vivo effects against T. cruzi, albeit in another test design. In vitro data showed that cynaropicrin was more effective than psilostachyin A. Ultrastructural alterations induced by cynaropicrin included shedding events, detachment of large portions of the plasma membrane, and vesicular bodies and large vacuoles containing membranous structures, suggestive of parasite autophagy. Acute toxicity studies showed that one of two mice died at a cynaropicrin dose of 400 mg/kg of body weight given intraperitoneally (i.p.). Although no major plasma biochemical alterations could be detected, histopathology demonstrated that the liver was the most affected organ in cynaropicrin-treated animals. Although cynaropicrin was as effective as benznidazole against trypomastigotes in vitro, the treatment (once or twice a day) of T. cruzi-infected mice (up to 50 mg/kg/day cynaropicrin) did not suppress parasitemia or protect against mortality induced by the Y and Colombiana strains. Psilostachyin A (0.5 to 50 mg/kg/day given once a day) was not effective in the acute model of T. cruzi infection (Y strain), reaching 100% animal mortality. Our data demonstrate that although it is very promising against African trypanosomes, cynaropicrin does not show efficacy compared to benznidazole in acute mouse models of T. cruzi infection.


Subject(s)
Chagas Disease/drug therapy , Liver/drug effects , Nitroimidazoles/pharmacology , Trypanocidal Agents/pharmacology , Trypanosoma cruzi/drug effects , Animals , Autophagy/drug effects , Cell Membrane/drug effects , Cell Membrane/ultrastructure , Chagas Disease/mortality , Chagas Disease/parasitology , Lactones/pharmacology , Liver/parasitology , Liver/pathology , Male , Mice , Microscopy, Electron, Transmission , Parasitic Sensitivity Tests , Sesquiterpenes/pharmacology , Survival Analysis , Treatment Failure , Trypanosoma cruzi/growth & development , Trypanosoma cruzi/ultrastructure , Vacuoles/drug effects , Vacuoles/ultrastructure
18.
Antimicrob Agents Chemother ; 57(9): 4151-63, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23774435

ABSTRACT

Chagas disease affects more than 10 million people worldwide, and yet, as it has historically been known as a disease of the poor, it remains highly neglected. Two currently available drugs exhibit severe toxicity and low effectiveness, especially in the chronic phase, while new drug discovery has been halted for years as a result of a lack of interest from pharmaceutical companies. Although attempts to repurpose the antifungal drugs posaconazole and ravuconazole (inhibitors of fungal sterol 14α-demethylase [CYP51]) are finally in progress, development of cheaper and more efficient, preferably Trypanosoma cruzi-specific, chemotherapies would be highly advantageous. We have recently reported that the experimental T. cruzi CYP51 inhibitor VNI cures with 100% survival and 100% parasitological clearance both acute and chronic murine infections with the Tulahuen strain of T. cruzi. In this work, we further explored the potential of VNI by assaying nitro-derivative-resistant T. cruzi strains, Y and Colombiana, in highly stringent protocols of acute infection. The data show high antiparasitic efficacy of VNI and its derivative (VNI/VNF) against both forms of T. cruzi that are relevant for mammalian host infection (bloodstream and amastigotes), with the in vivo potency, at 25 mg/kg twice a day (b.i.d.), similar to that of benznidazole (100 mg/kg/day). Transmission electron microscopy and reverse mutation tests were performed to explore cellular ultrastructural and mutagenic aspects of VNI, respectively. No mutagenic potential could be seen by the Ames test at up to 3.5 µM, and the main ultrastructural damage induced by VNI in T. cruzi was related to Golgi apparatus and endoplasmic reticulum organization, with membrane blebs presenting an autophagic phenotype. Thus, these preliminary studies confirm VNI as a very promising trypanocidal drug candidate for Chagas disease therapy.


Subject(s)
14-alpha Demethylase Inhibitors/pharmacology , Chagas Disease/drug therapy , Imidazoles/pharmacology , Oxadiazoles/pharmacology , Protozoan Proteins/antagonists & inhibitors , Sterol 14-Demethylase/metabolism , Trypanocidal Agents/pharmacology , Trypanosoma cruzi/drug effects , 14-alpha Demethylase Inhibitors/chemistry , Animals , Chagas Disease/mortality , Chagas Disease/parasitology , Drug Resistance/drug effects , Endoplasmic Reticulum/drug effects , Endoplasmic Reticulum/ultrastructure , Golgi Apparatus/drug effects , Golgi Apparatus/ultrastructure , Imidazoles/chemistry , Male , Mice , Microscopy, Electron, Transmission , Nitroimidazoles/pharmacology , Oxadiazoles/chemistry , Protozoan Proteins/metabolism , Thiazoles/pharmacology , Triazoles/pharmacology , Trypanocidal Agents/chemistry , Trypanosoma cruzi/enzymology , Trypanosoma cruzi/growth & development , Trypanosoma cruzi/ultrastructure
19.
Pharmaceutics ; 15(5)2023 May 19.
Article in English | MEDLINE | ID: mdl-37242777

ABSTRACT

Chagas disease (CD) caused by the protozoan Trypanosoma cruzi affects more than six million people worldwide. Treatment is restricted to benznidazole (Bz) and nifurtimox (Nf) that display low activity in the later chronic stage besides triggering toxic events that result in treatment abandonment. Therefore, new therapeutic options are necessary. In this scenario, natural products emerge as promising alternatives to treat CD. In the family Plumbaginaceae, Plumbago sp. exhibits a broad spectrum of biological and pharmacological activities. Thus, our main objective was to evaluate, in vitro and in silico, the biological effect of crude extracts of root and of aerial parts of P. auriculata, as well as its naphthoquinone Plumbagin (Pb) against T. cruzi. The phenotypic assays revealed potent activity of the root extract against different forms (trypomastigote and intracellular forms) and strains (Y and Tulahuen), with a compound concentration that reduced 50% of the number of the parasite (EC50) values ranging from 1.9 to 3.9 µg/mL. In silico analysis showed that Pb is predicted to have good oral absorption and permeability in Caco2 cells, besides excellent probability of absorption by human intestinal cells, without toxic or mutagenic potential effects, not being predicted as a substrate or inhibitor of P-glycoprotein. Pb was as potent as Bz against intracellular forms and displayed a superior trypanosomicidal effect (about 10-fold) in bloodstream forms (EC50 = 0.8 µM) as compared to the reference drug (8.5 µM). The cellular targets of Pb on T. cruzi were evaluated using electron microscopy assays and the findings on bloodstream trypomastigotes showed several cellular insults related to the autophagic process. Regarding toxicity in mammalian cells, the root extracts and the naphthoquinone present a moderate toxic profile on fibroblasts and cardiac cell lines. Then, aiming to reduce host toxicity, the root extract and Pb were tested in combination with Bz, and the data showed additive profiles with the sum of the fractional inhibitory concentration indexes (ΣFICIs) being 1.45 and 0.87, respectively. Thus, our work reveals the promising antiparasitic activity of Plumbago auriculata crude extracts and its purified naphthoquinone Plumbagin against different forms and strains of Trypanosoma cruzi in vitro.

20.
Acta Trop ; 242: 106924, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37037291

ABSTRACT

Atorvastatin (AVA) is a third-generation statin with several pleiotropic effects, considered the last synthetic pharmaceutical blockbuster. Recently, our group described the effects of AVA on DNA damage prevention and against Trypanosoma cruzi infection. In this study, our aim was to evaluate the efficacy, safety, and in silico pharmacokinetic profile of four hybrids of aminoquinolines with AVA 4a-d against T. cruzi using in vitro and in silico models. These synthetic compounds were designed by hybridization of the pentapyrrolic moiety of AVA with the aminoquinolinic unit of chloroquine or primaquine. Pharmacokinetics (ADME) and toxicity parameters were predicted by SwissADME, admetSAR and LAZAR in silico algorithms. The trypanocidal activity of AVA-quinoline hybrids were evaluated in vitro against amastigotes and trypomastigotes of T. cruzi, from Y (Tc II) and Tulahuen (Tc VI) strains. In vitro cardiocytotoxicity was assessed using primary cultures of mouse embryonic cardiac cells and in vitro hepatocytotoxicity on bidimensional and 3D-cultured HepG2 cells. Genotoxicity was evaluated by Ames test and micronucleus assay. Despite the overall good in silico ADMET profile, all tested compounds were predicted to be hepatotoxic. All hybrid derivatives presented high trypanocidal activity, against both trypomastigote and intracellular forms of T. cruzi, presenting EC50's lower than 1 µM besides superior selectivity than the reference drug, without evidences of cardiotoxicity in vitro. The compounds 4a and 4b presented a time-dependent toxicity in monolayer culture of HepG2 but no detectable toxic effects in their spheroids, opposing to the in silico prediction. We can conclude that the AVA-aminoquinoline hybrids presented a hit profile as antiparasitic agents in synthetic pharmaceutical innovation platforms.


Subject(s)
Antimalarials , Chagas Disease , Trypanocidal Agents , Trypanosoma cruzi , Animals , Mice , Atorvastatin/pharmacology , Atorvastatin/therapeutic use , Pyrroles/pharmacology , Pyrroles/therapeutic use , Chagas Disease/parasitology , Aminoquinolines/pharmacology , Antimalarials/pharmacology , DNA Damage , Pharmaceutical Preparations , Trypanocidal Agents/pharmacology , Trypanocidal Agents/therapeutic use
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