RESUMEN
Leishmaniasis is a neglected tropical infectious disease with thousands of cases annually; it is of great concern to global health, particularly the most severe form, visceral leishmaniasis. Visceral leishmaniasis treatments are minimal and have severe adverse effects. As guanidine-bearing compounds have shown antimicrobial activity, we analyzed the cytotoxic effects of several guanidine-bearing compounds on Leishmania infantum in their promastigote and amastigote forms in vitro, their cytotoxicity in human cells, and their impact on reactive nitrogen species production. LQOFG-2, LQOFG-6, and LQOFG-7 had IC50 values of 12.7, 24.4, and 23.6 µM, respectively, in promastigotes. These compounds exhibited cytotoxicity in axenic amastigotes at 26.1, 21.1, and 18.6 µM, respectively. The compounds showed no apparent cytotoxicity in cells from healthy donors. To identify mechanisms of action, we evaluated cell death processes by annexin V and propidium iodide staining and nitrite production. Guanidine-containing compounds caused a significant percentage of death by apoptosis in amastigotes. Independent of L. infantum infection, LQOFG-7 increased nitrite production in peripheral blood mononuclear cells, which suggests a potential mechanism of action for this compound. Therefore, these data suggest that guanidine derivatives are potential anti-microbial molecules, and further research is needed to fully understand their mechanism of action, especially in anti-leishmanial studies.
RESUMEN
The leishmaniasis is a neglected disease caused by a group of protozoan parasites from the genus Leishmania whose treatment is limited, obsolete, toxic, and ineffective in certain cases. These characteristics motivate researchers worldwide to plan new therapeutic alternatives for the treatment of leishmaniasis, where the use of cheminformatics tools applied to computer-assisted drug design has allowed research to make great advances in the search for new drugs candidates. In this study, a series of 2-amino-thiophene (2-AT) derivatives was screened virtually using QSAR tools, ADMET filters and prediction models, allowing direct the synthesis of compounds, which were evaluated in vitro against promastigotes and axenic amastigotes of Leishmania amazonensis. The combination of different descriptors and machine learning methods led to obtaining robust and predictive QSAR models, which was obtained from a dataset composed of 1862 compounds extracted from the ChEMBL database, with correct classification rates ranging from 0.53 (for amastigotes) to 0.91 (for promastigotes), allowing to select eleven 2-AT derivatives, which do not violate Lipinski's rules, exhibit good druglikeness, and with probability ≤70% of potential activity against the two evolutionary forms of the parasite. All compounds were properly synthesized and 8 of them were shown to be active at least against one of the evolutionary forms of the parasite with IC50 values lower than 10 µM, being more active than the reference drug meglumine antimoniate, and showing low or no citotoxicity against macrophage J774.A1 for the most part. Compounds 8CN and DCN-83, respectively, are the most active against promastigote and amastigote forms, with IC50 values of 1.20 and 0.71 µM, and selectivity indexes (SI) of 36.58 and 119.33. Structure Activity Relationship (SAR) study was carried out and allowed to identify some favorable and/or essential substitution patterns for the leishmanial activity of 2-AT derivatives. Taken together, these findings demonstrate that the use of ligand-based virtual screening proved to be quite effective and saved time, effort, and money in the selection of potential anti-leishmanial agents, and confirm, once again that 2-AT derivatives are promising hit compounds for the development of new anti-leishmanial agents.
Asunto(s)
Antiprotozoarios , Leishmania , Leishmaniasis , Humanos , Antiprotozoarios/química , Tiofenos/farmacología , Tiofenos/uso terapéutico , Leishmaniasis/tratamiento farmacológico , Leishmaniasis/parasitología , Diseño de FármacosRESUMEN
Leishmaniasis is a poverty-related disease endemic in 98 countries worldwide, with morbidity and mortality increasing daily. All currently used first-line and second-line drugs for the treatment of leishmaniasis exhibit several drawbacks including toxicity, high costs and route of administration. Consequently, the development of new treatments for leishmaniasis is a priority in the field of neglected tropical diseases. The aim of this work is to develop computational models those allow the identification of new chemical compounds with potential anti-leishmanial activity. A data set of 116 organic chemicals, assayed against promastigotes of Leishmania amazonensis, is used to develop the theoretical models. The cutoff value to consider a compound as active one was IC50≤1.5µM. For this study, we employed Dragon software to calculate the molecular descriptors and WEKA to obtain machine learning (ML) models. All ML models showed accuracy values between 82% and 91%, for the training set. The models developed with k-nearest neighbors and classification trees showed sensitivity values of 97% and 100%, respectively; while the models developed with artificial neural networks and support vector machine showed specificity values of 94% and 92%, respectively. In order to validate our models, an external test-set was evaluated with good behavior for all models. A virtual screening was performed and 156 compounds were identified as potential anti-leishmanial by all the ML models. This investigation highlights the merits of ML-based techniques as an alternative to other more traditional methods to find new chemical compounds with anti-leishmanial activity.
Asunto(s)
Antiprotozoarios/farmacología , Leishmania/efectos de los fármacos , Aprendizaje Automático , Antiprotozoarios/química , Evaluación Preclínica de Medicamentos , Modelos Moleculares , Pruebas de Sensibilidad Parasitaria , Programas InformáticosRESUMEN
The primary choice of drugs to treat Leishmaniasis are the pentavalent antimony-based compounds, nevertheless these drugs presented undesirable side effects. However, safe natural compounds could be used in combination with these drugs to enhance their activity. The aim of this study was to evaluate the sinergism of capsaicin and piperine, isolated from Capsicum frutescens and Piper nigrum, respectively, in combination with meglumine antimoniate against Leishmania infantum promastigote and amastigote forms. Each compound was mixed with the standard drug in several percentage mixtures and tested at various concentrations. Capsaicin and piperine in combination with meglumine antimoniate (25% + 75%) showed better anti-leishmanial activity with EC50â¯=â¯4.31⯱â¯0.44 e 7.25⯱â¯4.84⯵g/mL against promastigote and amastigote forms, respectively. The results point that these spice alkaloids are suitable compounds to be administered in combinations with antileishmanial drugs to improve their action.
Asunto(s)
Alcaloides/farmacología , Antiprotozoarios/farmacología , Benzodioxoles/farmacología , Capsaicina/farmacología , Leishmania infantum/efectos de los fármacos , Meglumina/farmacología , Compuestos Organometálicos/farmacología , Piperidinas/farmacología , Alcamidas Poliinsaturadas/farmacología , Alcaloides/uso terapéutico , Antiprotozoarios/uso terapéutico , Benzodioxoles/uso terapéutico , Capsaicina/uso terapéutico , Cromatografía Líquida de Alta Presión , Sinergismo Farmacológico , Concentración 50 Inhibidora , Leishmaniasis Visceral/tratamiento farmacológico , Espectroscopía de Resonancia Magnética , Meglumina/uso terapéutico , Antimoniato de Meglumina , Compuestos Organometálicos/uso terapéutico , Piperidinas/uso terapéutico , Alcamidas Poliinsaturadas/uso terapéutico , Espectrofotometría UltravioletaRESUMEN
Conventional chemotherapy for leishmaniasis includes considerably toxic drugs and reports of drug-resistance are not uncommon. Liposomal encapsulated drugs appear as an option for the treatment of leishmaniasis, providing greater efficacy for the active and reducing its side effects by promoting superior tissue absorption, favouring drug penetration into the macrophages, and retarding its clearance from the site of action. In this paper, a review on the advances achieved with liposome-based anti-leishmaniasis drug delivery systems is presented. Formulations prepared with either conventional or modified (sugar-coated, cationic, niosomes, peptides- and antibodies-bounded) liposomes for the delivery of pentavalent antimonials, amphotericin B, pentamidine, paromomycyn, and miltefosine were covered. This literature review depicts a scenario of no effective therapeutic agents for the treatment of this neglected disease, where liposomal formulations appear to improve the effectiveness of the available antileishmania agents.
Asunto(s)
Antiprotozoarios/química , Antiprotozoarios/uso terapéutico , Leishmaniasis/tratamiento farmacológico , Liposomas/química , Anfotericina B/química , Anfotericina B/farmacología , Anfotericina B/uso terapéutico , Animales , Antiprotozoarios/farmacología , Composición de Medicamentos , Sistemas de Liberación de Medicamentos , Liberación de Fármacos , Humanos , Nanopartículas , Paromomicina/química , Paromomicina/farmacología , Paromomicina/uso terapéutico , Tamaño de la Partícula , Pentamidina/química , Pentamidina/farmacología , Pentamidina/uso terapéutico , Fosforilcolina/análogos & derivados , Fosforilcolina/química , Fosforilcolina/farmacología , Fosforilcolina/uso terapéutico , Propiedades de SuperficieRESUMEN
ABSTRACT INTRODUCTION: Cutaneous leishmaniasis (CL) is a tropical disease that affects millions of individuals worldwide. The current drugs for CL may be effective but have serious side effects; hence, alternatives are urgently needed. Although plant-derived materials are used for the treatment of various diseases in 80% of the global population, the validation of these products is essential. Gelatin capsules containing dried Artemisia annua leaf powder were recently developed as a new herbal formulation (totum) for the oral treatment of malaria and other parasitic diseases. Here, we aimed to determine the usefulness of A. annua gel capsules in CL. METHODS: The antileishmanial activity and cytotoxicity of A. annua L. capsules was determined via in vitro and in vivo studies. Moreover, a preliminary evaluation of its therapeutic potential as antileishmanial treatment in humans was conducted in 2 patients with uncomplicated CL. RESULTS: Artemisia annua capsules showed moderate in vitro activity in amastigotes of Leishmania (Viannia) panamensis; no cytotoxicity in U-937 macrophages or genotoxicity in human lymphocytes was observed. Five of 6 (83.3%) hamsters treated with A. annua capsules (500mg/kg/day) for 30 days were cured, and the 2 examined patients were cured 45 days after initiation of treatment with 30g of A. annua capsules, without any adverse reactions. Both patients remained disease-free 26 and 24 months after treatment completion. CONCLUSION: Capsules of A. annua L. represent an effective treatment for uncomplicated CL, although further randomized controlled trials are needed to validate its efficacy and safety.
Asunto(s)
Humanos , Animales , Masculino , Femenino , Adulto , Extractos Vegetales/uso terapéutico , Extractos Vegetales/farmacología , Leishmaniasis Cutánea/tratamiento farmacológico , Artemisia annua/química , Antiprotozoarios/uso terapéutico , Antiprotozoarios/farmacología , Cricetinae , Resultado del Tratamiento , Hojas de la Planta/química , Pruebas de Sensibilidad Parasitaria , Leishmania/efectos de los fármacosRESUMEN
Leishmaniasis is a neglected tropical disease (NTDs), endemic in 88 countries that affect more than 12 million people. Current drugs are limited due to their toxicity, development of biological resistance, length of treatment and high cost. Thus, the search for new effective and less toxic treatments is an urgent need. In this study, we report the synthesis of 3 new amide derivatives of hederagenin (22-24) with yields between 70% and 90%, along with 57 other derivatives of hederagenin (1-21, 25-60) carrying different groups at C-28 previously reported by our group, and the results of their in vitro ability to inhibit the growth of Leishmania infantum. Some derivatives (3, 4, 44, 49 and 52), showed activity at micromolar level and low toxicity against BGM and HepG2 cells. Moreover, the ability of hederagenin derivatives 3 (IC50 = 9.7 µM), 4 (12 µM), 44 (11 µM) and 49 (2 µM), to prevent proliferation of intracellular amastigote forms of L. infantum and their higher selectivity index and low toxicity compared to commercial positive drug control of choice (potassium antimonyl tartrate trihydrate) (IC50 = 80 µM, SI = 0.1), make these compounds promising candidates for the treatment of leishmaniasis.
Asunto(s)
Antiprotozoarios/química , Antiprotozoarios/farmacología , Leishmania infantum/efectos de los fármacos , Ácido Oleanólico/análogos & derivados , Saponaria/química , Antiprotozoarios/toxicidad , Células Hep G2 , Humanos , Espacio Intracelular/efectos de los fármacos , Espacio Intracelular/parasitología , Ácido Oleanólico/química , Ácido Oleanólico/farmacología , Ácido Oleanólico/toxicidad , Relación Estructura-ActividadRESUMEN
The control and treatment of Leishmaniasis, a neglected and infectious disease affecting approximately 12 million people worldwide, are challenging. Leishmania parasites multiply intracellularly within macrophages located in deep skin and in visceral tissues, and the currently employed treatments for this disease are subject to significant drawbacks, such as resistance and toxicity. Thus, the search for new Leishmaniasis treatments is compulsory, and Ocotea duckei Vattimo, a plant-derived product from the biodiverse Brazilian flora, may be a promising new treatment for this disease. In this regard, the aim of this work was to develop and characterize a delivery system based on solid lipid nanoparticles (SLN) that contain the liposoluble lignan fraction (LF) of Ocotea duckei Vattimo, which targets the Leishmania phagolysosome of infected macrophages. LF-loaded SLNs were obtained via the hot microemulsion method, and their physical and chemical properties were comprehensively assessed using PCS, AFM, SEM, FT-IR, DSC, HPLC, kinetic drug release studies, and biological assays. The size of the developed delivery system was 218.85±14.2 nm, its zeta potential was -30 mV and its entrapment efficiency (EE%) was high (the EEs% of YAN [yangambin] and EPI-YAN [epi-yangambin] markers were 94.21±0.40% and 94.20±0.00%, respectively). Microscopy, FT-IR and DSC assays confirmed that the delivery system was nanosized and indicated a core-shell encapsulation model, which corroborated the measured kinetics of drug release. The total in vitro release rates of YAN and EPI-YAN in buffer (with sink conditions attained) were 29.6±8.3% and 34.3±8.9%, respectively, via diffusion through the cellulose acetate membrane of the SLN over a period of 4 h. After 24 h, the release rates of both markers reached approximately 45%, suggesting a sustained pattern of release. Mathematical modeling indicated that both markers, YAN and EPI-YAN, followed matrix diffusion-based release kinetics (Higuchi's model) with an estimated diffusion coefficient (D) of 1.3.10(-6) cm(2)/s. The LF-loaded SLNs were non-toxic to murine macrophages (20-80 µg mL(-1) range) and exerted a prominent anti-leishmanial effect (20 µg mL(-1)). These data suggest this new and well-characterized lipid nanoparticle delivery system safely and effectively kills Leishmania and warrants further clinical investigation.
Asunto(s)
Antiparasitarios/administración & dosificación , Antiparasitarios/química , Productos Biológicos/administración & dosificación , Productos Biológicos/química , Leishmania/efectos de los fármacos , Leishmaniasis/tratamiento farmacológico , Animales , Bioensayo/métodos , Brasil , Química Farmacéutica/métodos , Difusión , Portadores de Fármacos/química , Sistemas de Liberación de Medicamentos/métodos , Cinética , Leishmaniasis/parasitología , Lignanos/administración & dosificación , Lignanos/química , Lípidos/administración & dosificación , Lípidos/química , Macrófagos/parasitología , Ratones , Ratones Endogámicos C57BL , Microscopía de Fuerza Atómica/métodos , Nanopartículas/administración & dosificación , Nanopartículas/química , Ocotea/química , Tamaño de la Partícula , Extractos Vegetales/administración & dosificación , Extractos Vegetales/química , Piel/parasitología , Espectroscopía Infrarroja por Transformada de Fourier/métodosRESUMEN
Abstract In the present context of emergence of resistance aligned with the conventional anti-leishmanial drugs and occasional treatment failure compelled us to continue the search for replaceable therapeutic leads against Leishmaniainfection. Various ginger spices of the Zingiberaceae family are widely used as spices, flavouring agents, and medicines in Southeast Asia because of their unique flavour as well as due to their medicinal properties. Zerumbone, a natural component of Zingiber zerumbet (L.) Smith, has been studied for its pharmacological potential as antiulcer, antioxidant, anticancer, and antimicrobial. In this study, we have shown that zerumbone could induce ROS mediated apoptosis in Leishmania donovani promastigotes and also found effective in reducing intracellular amastigotes in infected-macrophages. We emphasized the potential of zerumbone to be employed in the development of new therapeutic drugs against L. donovaniinfection and provided the basis for future research on the application of transitional medicinal plants.
Asunto(s)
Animales , Apoptosis/efectos de los fármacos , Leishmania donovani/efectos de los fármacos , Macrófagos/microbiología , Estrés Oxidativo/efectos de los fármacos , Sesquiterpenos/farmacología , Zingiberaceae/química , Leishmania donovani/ultraestructura , Ratones Endogámicos BALB C , Microscopía Electrónica de Rastreo , Pruebas de Sensibilidad Parasitaria , Sesquiterpenos/aislamiento & purificaciónRESUMEN
ETHNOPHARMACOLOGICAL RELEVANCE: Plant-based preparations are extensively used in Surinamese folk medicine for treating leishmaniasis, but often without a scientific rationale. AIM OF THE STUDY: To evaluate 25 Surinamese medicinal plants for their potential efficacy against leishmaniasis. MATERIALS AND METHODS: Concentrated plant extracts were evaluated for their effect on the viability of L. (V.) guyanensis AMC, L. (L.) major NADIM5, and L. (L.) donovani GEDII promastigotes, as well as intracellular amastigotes of L. (L.) donovani BHU814 in infected THP-1 cells. Selectivity was assessed by cytotoxicity against THP-1 cells. RESULTS: The only plant extract that showed potentially meaningful anti-leishmanial activity was that from Solanum lycocarpum that displayed mean IC50 values of about 51, 61, and <16 µg/mL against L. (V) guyanensis, L. (L) major, and L. (L) donovani promastigotes, respectively; about 374 µg/mL against L. (L) donovani amastigotes; and >500 µg/mL against THP-1 cells. The Bryophyllum pinnatum, Inga alba, and Quassia amara extracts displayed moderate to high IC50 values against promastigotes (about 51 to >500 µg/mL) and/or amastigotes (about 224 to >500 µg/mL) but were relatively toxic to THP-1 cells (IC50 values <16 to about 42 µg/mL). The remaining plant extracts exhibited in many cases IC50 values close to, around, or above 500µg/mL against promastigotes, amastigotes, and THP-1 cells. CONCLUSIONS: The S. lycocarpum preparation may be useful against leishmaniasis and may have a good safety index, warranting further investigations into its active constituents and mechanism(s) of action.
Asunto(s)
Antiprotozoarios/farmacología , Leishmania donovani/efectos de los fármacos , Extractos Vegetales/farmacología , Plantas Medicinales , Solanum , Antiprotozoarios/toxicidad , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Humanos , Leishmania donovani/fisiología , Leishmaniasis/tratamiento farmacológico , Extractos Vegetales/toxicidad , Suriname , Encuestas y CuestionariosRESUMEN
In the present context of emergence of resistance aligned with the conventional anti-leishmanial drugs and occasional treatment failure compelled us to continue the search for replaceable therapeutic leads against Leishmania infection. Various ginger spices of the Zingiberaceae family are widely used as spices, flavouring agents, and medicines in Southeast Asia because of their unique flavour as well as due to their medicinal properties. Zerumbone, a natural component of Zingiber zerumbet (L.) Smith, has been studied for its pharmacological potential as antiulcer, antioxidant, anticancer, and antimicrobial. In this study, we have shown that zerumbone could induce ROS mediated apoptosis in Leishmania donovani promastigotes and also found effective in reducing intracellular amastigotes in infected-macrophages. We emphasized the potential of zerumbone to be employed in the development of new therapeutic drugs against L. donovani infection and provided the basis for future research on the application of transitional medicinal plants.
Asunto(s)
Apoptosis/efectos de los fármacos , Leishmania donovani/efectos de los fármacos , Macrófagos/microbiología , Estrés Oxidativo/efectos de los fármacos , Sesquiterpenos/farmacología , Zingiberaceae/química , Animales , Leishmania donovani/ultraestructura , Ratones Endogámicos BALB C , Microscopía Electrónica de Rastreo , Pruebas de Sensibilidad Parasitaria , Sesquiterpenos/aislamiento & purificaciónRESUMEN
The leishmaniases are severe parasitic diseases that occur worldwide, caused by protozoa of the genus Leishmania. Studies with medicinal plants can lead to a range of possibilities for treating and improving the patients' quality of life. Research on Azadirachta indica fractions and extracts has shown that they have excellent anti-leishmanial activity based on bioactivity-guided fractionation of ethanolic extracts of leaves and seeds and in vitro activity against promastigotes. In this research the most efficient extracts and fractions were selected for tests on intracellular amastigotes of Leishmania amazonensis. The ethanolic extract of the leaves and dichloromethane and chloroform fractions had IC50 values of 38, 3.9 and 1.2 μg/mL for promastigotes and 9.8, 1.1 and 0.6 μg/mL for amastigotes, respectively, at 72 hours. For the ethanolic extract and dichloromethane fraction from nut tegument, the IC50 was 2.7 and 2.1 μg/mL for promastigotes and 0.4 and 0.6 μg/mL for amastigotes. The cytotoxicity of the fractions presented selectivity that was between 8 to 32 times more toxic to promastigotes and 15 to 72 times to amastigotes than to macrophages. The extracts and fractions from leaves and fruits were more effective against amastigotes, and the fractionation increased activity against both promastigotes and amastigotes, enabling us to obtain potentially active fractions with low toxicity.
Asunto(s)
Animales , Femenino , Ratones , Antiprotozoarios/farmacología , Azadirachta/química , Leishmania mexicana/efectos de los fármacos , Extractos Vegetales/farmacología , Frutas/química , Ratones Endogámicos BALB C , Macrófagos/efectos de los fármacos , Pruebas de Sensibilidad Parasitaria , Hojas de la Planta/químicaRESUMEN
The dichloromethane extract of Almeidea coerulea stems yielded the (11-hydroxyrutaecarpine alkaloid reported for the first time from this species) and the triterpene (28-hydroxy-28, 29-dihydrolupeol). The dictamine, skimianine, sitosterol and stigmasterol were also isolated from methanol extract. Extracellular forms of Leishmania amazonensis (promastigotes) was tested with dichloromethane extract and 28-hydroxy-28, 29-dihydrolupeol with showed anti-leishmanial activity above 0.1 mg/mL and 75µg/mL (inhibited 50 percent promastigote growth), respectively.
RESUMEN
A series of ring substituted 3-phenyl-1-(1,4-di-N-oxide quinoxalin-2-yl)-2-propen-1-one derivatives were synthesized and tested for in vitro leishmanicidal activity against amastigotes of Leishmania amazonensis in axenical cultures and murine infected macrophages. Structure-activity relationships demonstrated the importance of a radical methoxy at position R3', R4' and R5'. (2E)-3-(3,4,5-trimethoxy-phenyl)-1-(3,6,7-trimethyl-1,4-dioxy-quinoxalin-2-yl)-propenone was the most active. Cytotoxicity on macrophages revealed that this product was almost six times more active than toxic.