RESUMO
This study aimed to develop microemulsions (MEs) containing α-bisabolol for the topical treatment of cutaneous leishmaniasis (CL). Initially, pseudoternary phase diagrams were developed using α-bisabolol as the oil phase, Eumulgin® CO 40 as the surfactant, Polymol® HE as the co-surfactant, and distilled water as the aqueous phase. Two transparent liquid systems (TLS) containing 5% of α-bisabolol were selected and characterized (F5E25 and F5EP25). Next, skin permeation and retention assays were performed using Franz cells. The interaction of the formulation with the stratum corneum (SC) was evaluated using the FTIR technique. The cytotoxicity was evaluated in murine peritoneal macrophages. Finally, the antileishmanial activity of microemulsions was determined in promastigotes and amastigotes of L. amazonensis (strain MHOM/BR/77/LTB 0016). As a result, the selected formulations showed isotropy, nanometric size (below 25 nm), Newtonian behavior and pH ranging from 6.5 to 6.9. The MEs achieved a 2.5-fold increase in the flux and skin-permeated amount of α-bisabolol. ATR-FTIR results showed that microemulsions promoted fluidization and extraction of lipids and proteins of the stratum corneum, increasing the diffusion coefficient and partition coefficient of the drug in the skin. Additionally, F5E25 and F5EP25 showed higher activity against promastigotes (IC50 13.27 and 18.29, respectively) compared to unencapsulated α-bisabolol (IC50 53.8). Furthermore, F5E25 and F5EP25 also showed antileishmanial activity against intracellular amastigotes of L. amazonensis, with IC50 50 times lower than free α-bisabolol and high selectivity index (up to 15). Therefore, the systems obtained are favorable to topical administration, with significant antileishmanial activity against L. amazonensis promastigotes and amastigotes, being a promising system for future in vivo trials.
Assuntos
Emulsões , Macrófagos Peritoneais , Sesquiterpenos Monocíclicos , Sesquiterpenos , Pele , Animais , Sesquiterpenos Monocíclicos/farmacologia , Sesquiterpenos Monocíclicos/química , Emulsões/química , Camundongos , Sesquiterpenos/farmacologia , Sesquiterpenos/química , Pele/parasitologia , Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/parasitologia , Leishmaniose Cutânea/tratamento farmacológico , Leishmaniose Cutânea/parasitologia , Espectroscopia de Infravermelho com Transformada de Fourier , Absorção Cutânea/efeitos dos fármacos , Camundongos Endogâmicos BALB C , Feminino , Leishmania/efeitos dos fármacos , Tensoativos/farmacologia , Tensoativos/química , Antiprotozoários/farmacologia , Antiprotozoários/químicaRESUMO
Millions of people worldwide are affected by leishmaniasis, caused by the Leishmania parasite. Effective treatment is challenging due to the biological complexity of the parasite, drug toxicity, and increasing resistance to conventional drugs. To combat this disease, the development of specific strategies to target and selectively eliminate the parasite is crucial. This Review highlights the importance of amino acids in the developmental stages of Leishmania as a factor determining whether the infection progresses or is suppressed. It also explores the use of peptides as alternatives in parasite control and the development of novel targeted treatments. While these strategies show promise for more effective and targeted treatment, further studies to address the remaining challenges are imperative.
Assuntos
Aminoácidos , Antiprotozoários , Leishmania , Leishmaniose , Peptídeos , Leishmania/efeitos dos fármacos , Aminoácidos/química , Leishmaniose/tratamento farmacológico , Leishmaniose/parasitologia , Humanos , Peptídeos/farmacologia , Peptídeos/química , Antiprotozoários/farmacologia , Antiprotozoários/química , AnimaisRESUMO
A leishmaniose é uma zoonose de ampla distribuição mundial, causada pelos parasitas tripanossomatídeos do gênero Leishmania. Infelizmente, o arsenal terapêutico disponível é precário, mas vê-se crescente o interesse científico pela busca do potencial de derivados nitroheterocíclicos como alternativas terapêuticas. Nesse contexto, este trabalho analisou o potencial de derivados 5-nitro-2-furfurilidênicos contra diferentes cepas de Leishmania, assim como investigou um possível modo de ação para esta classe de nitrocompostos. Para tal, a quimioteca foi sintetizada de acordo com publicações prévias do grupo. O potencial de inibição de crescimento das culturas de promastigotas de L. (L.) infantum (Linf) e L. (L.) major (Lmaj) foi determinado, utilizando miltefosina (MILT) (Linf - IC50: 8,28±0,33 µM), anfotericina B (AMB) (Linf - IC50: 0,02±0,002 µM) e nifurtimox (NFX) (Lmaj - IC50: 3,5±0,09 µM) como referência. A maioria dos compostos apresentaram maior potencial que as referênias, destacando o composto 40 (Linf - IC50: 0,2±0,019 µM/ Lmaj - IC50: 0,087 ± 0,001 µM) como mais eficaz. Contra as formas amastigotas intracelulares, para Linf os compostos 40, 13 e 15 foram mais eficazes em reduzir a carga parasitária dos macrófagos infectados que fármacos de referência. Para Lmajor, o composto 40 (IC50: 0,006 ± 0,0003 µM) foi mais ativo que o NFX (IC50: 2,15 ± 0,01 µM). Também foi determinada a atividade da quimioteca frente a enzima nitrorredutase (NTR1), utilizando cepas de T. brucei superexpressantes de NTR1, e os compostos analisados foram até 18 vezes mais eficazes que à cepa wild-type. Ademais, a partir da análise exploratória de dados por análise de componentes principais (PCA) e de grupamentos hierárquicos (HCA), foi reconhecida a influência das propriedades relacionadas com o equilíbrio hidrófilo-lipófilo e da natureza estérica/geométrica das moléculas para atividade anti-Leishmania
Leishmaniasis is a worldwide zoonosis caused by trypanosomatid parasites of the genus Leishmania. Unfortunately, the available therapeutic arsenal is precarious, but there is growing scientific interest in searching the potential of nitroheterocyclic derivatives as therapeutic alternatives. In this context, this work analyzed the potential of 5-nitro-2-furfurylidene derivatives against different Leishmania strains, as well as investigated the potential mode of action for this nitro compounds class. To this end, the chemolibrary was synthesized according to our group's previous publications. The growth inhibitory potential potential for promastigote cultures of L. (L.) infantum (Linf) and L. (L.) major (Lmaj) was determined using miltefosine (MILT) (Linf - IC50: 8.28±0.33 µM), amphotericin B (AMB) (Linf - IC50: 0.02±0.002 µM) and nifurtimox (NFX) (Lmaj - IC50: 3.5±0.09 µM) as reference. Most of the compounds were more potent than the references, highlighting compound 40 (Linf - IC50: 0.2±0.019 µM/ Lmaj - IC50: 0.087 ± 0.001 µM) as the most effective. Against intracellular amastigote, for Linf, compounds 40, 13 and 15 were more effective in reducing the parasite load of infected macrophages than reference drugs. For Lmajor, compound 40 (IC50: 0.006 ± 0.0003 µM) was more active than NFX (IC50: 2.15 ± 0.01 µM). The activity against nitroreductase (NTR1) enzyme was determined using overexpressing NTR1 mutant T. brucei strains, and the analyzed compounds were up to 18 times more effective than wild-type. Furthermore, exploratory data analysis using principal component analysis (PCA) and hierarchical clustering (HCA) methods were used. The influence of properties related to the hydrophiliclipophilic balance and the steric/geometric nature of the molecules was associated with the anti-Leishmanial activity
Assuntos
Terapias Complementares/instrumentação , Leishmaniose/patologia , Análise de Componente Principal/classificação , Leishmania/metabolismo , Nitrorredutases/análise , Preparações Farmacêuticas/análise , Análise de Dados , Nitrocompostos/agonistasRESUMO
Abstract The aim was to scrutinize the in vivo and in vitro activities against Leishmania tropica with compounds of Oxyresveratrol, Quercetin O-Hexoside, and Quercetin 3-Glucoside. The in vitro outcomes against Leishmania were analyzed for 24-48 hours on L. tropica KWH23 promastigotes with compounds materials having 50 - 200 µg/mL concentration with negative control and standard drug Amphotericin B. The compounds were analyzed in L. tropica infected BALB/c mice against Leishmania tropica. The Quercetin 3-Glucoside shows mean inhibition of extracellular promastigotes after 48 hours at 50, 100, 150, 200 µg/mL were 91.02 ± 0.12, 94.50 ± 0.07, 96.15 ± 0.17 and 97.01 ± 0.08 % respectively. In BALB/c mice, the intracellular amastigotes were 91% cured at 200 µg/mL and mean lesion size decreased to 0.41 ± 0.21 mm (p < 0.01). The result shows that Quercetin 3-Glucoside possesses significant anti-leishmanial activity.
RESUMO
A series of mononuclear coordination or organometallic AuI /AuIII complexes (1-9) have been comparatively studied inâ vitro for their antileishmanial activity against promastigotes and amastigotes, the clinically relevant parasite form, of Leishmania amazonensis and Leishmania braziliensis. One of the cationic AuI bis-N-heterocyclic carbenes (3) has low EC50 values (ca. 4â µM) in promastigotes cells and no toxicity in host macrophages. Together with two other AuIII complexes (6 and 7), the compound is also extremely effective in intracellular amastigotes from L.â amazonensis. Initial mechanistic studies include an evaluation of the gold complexes' effect on L.â amazonensis' plasma membrane integrity.
Assuntos
Antiprotozoários/farmacologia , Leishmania/efeitos dos fármacos , Compostos Organoáuricos/farmacologia , Animais , Antiprotozoários/química , Células Cultivadas , Camundongos , Camundongos Endogâmicos BALB C , Estrutura Molecular , Compostos Organoáuricos/química , Testes de Sensibilidade ParasitáriaRESUMO
BACKGROUND: Leishmaniasis is a neglected tropical disease caused by protozoa of the genus Leishmania. Current treatments are restricted to a small number of drugs that display both severe side effects and a potential for parasites to develop resistance. A new N-(3,4-methylenedioxyphenyl)-N'- (2-phenethyl) thiourea compound (thiourea 1) has shown promising in vitro activity against Leishmania amazonensis with an IC50 of 54.14 µM for promastigotes and an IC50 of 70 µM for amastigotes. OBJECTIVE: To develop a formulation of thiourea 1 as an oral treatment for leishmaniasis, it was incorporated into Nanoparticles (NPs), a proven approach to provide long-acting drug delivery systems. METHODS: Poly (D,L-Lactic-co-Glycolic Acid) (PLGA) polymeric NPs containing thiourea 1 were obtained through a nanoprecipitation methodology associated with solvent evaporation. The NPs containing thiourea 1 were characterized for Encapsulation Efficiency (EE%), reaction yield (% w/w), surface charge, particle size and morphology by Transmission Electron Microscopy (TEM). RESULTS: NPs with thiourea 1 showed an improved in vitro leishmanicidal activity with a reduction in its cytotoxicity against macrophages (CC50>100 µg/mL) while preserving its IC50 against intracellular amastigotes (1.46 ± 0.09 µg/mL). This represents a parasite Selectivity Index (SI) of 68.49, which is a marked advancement from the reference drug pentamidine (SI = 30.14). CONCLUSION: The results suggest that the incorporation into NPs potentiated the therapeutic effect of thiourea 1, most likely by improving the selective delivery of the drug to the phagocytic cells that are targeted for infection by L. amazonensis. This work reinforces the importance of nanotechnology in the acquisition of new therapeutic alternatives for oral treatments.
Assuntos
Antiprotozoários/administração & dosagem , Portadores de Fármacos/química , Leishmania mexicana/efeitos dos fármacos , Leishmaniose Cutânea/tratamento farmacológico , Tioureia/administração & dosagem , Animais , Antiprotozoários/farmacocinética , Antiprotozoários/toxicidade , Modelos Animais de Doenças , Liberação Controlada de Fármacos , Humanos , Leishmaniose Cutânea/parasitologia , Macrófagos/parasitologia , Camundongos , Nanopartículas/química , Testes de Sensibilidade Parasitária , Tamanho da Partícula , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Cultura Primária de Células , Tioureia/análogos & derivados , Tioureia/farmacocinética , Tioureia/toxicidade , Testes de Toxicidade AgudaRESUMO
A series of seven chalcone-thiosemicarbazones (5a-5g) were synthesized and evaluated as potential new drugs (anti-leishmanial effect). Although four of the chalcone-thiosemicarbazones are already known, none of them or any compound in this class has been previously investigated for their effects on parasites of the Leishmania genus. The compounds were prepared in satisfactory yields (40-75%) and these compounds were evaluated against promastigotes, axenic amastigotes and intracellular amastigotes of L. amazonensis after 48 h of culture. The half maximal inhibitory concentration (IC50) values of the intracellular amastigotes were determined to be in the range of 3.40 to 5.95 µM for all compounds assayed. The selectivity index showed value of 15.05 for 5a, whereas pentamidine (reference drug) was more toxic in our model (SI = 2.32). Furthermore, to understand the preliminary relationship between the anti-leishmanial activity of the chalcone-thiosemicarbazones, their electronic (σ), steric (MR) and lipophilicity (π) properties were correlated, and the results indicated that moieties with electronic withdrawing effects increase the anti-leishmanial activity. The preliminary pharmacokinetic evaluation of one of the most active compound (5e) was studied via interaction to human serum albumin (HSA) using multiple spectroscopic techniques combined with molecular docking. The results of antiparasitic effects against L. amazonensis revealed the chalcone-thiosemicarbazone class to be novel prototypes for drug development against leishmaniasis.
Assuntos
Antiprotozoários/farmacologia , Chalconas/farmacologia , Leishmania/efeitos dos fármacos , Tiossemicarbazonas/farmacologia , Animais , Antiprotozoários/química , Chalconas/química , Leishmania/crescimento & desenvolvimento , Macrófagos/efeitos dos fármacos , Macrófagos/parasitologia , Camundongos Endogâmicos BALB C , Ligação Proteica , Albumina Sérica Humana/química , Tiossemicarbazonas/químicaRESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Leishmaniasis is a parasitic disease that affects people all over the world. The number of cases of leishmaniasis is increasing and the drugs used for its treatment are toxic and not always effective. The recognition of the global nature of this disease and its direct or indirect effects on health economics and actions focuses attention on the development of new therapeutic options. In Brazil, this parasitic disease is endemic in many regions. The plants used by the population against leishmaniasis can be good starting points in the search of new lead compounds for antileishmanial drugs. AIM OF THE STUDY: The aim of the present study was to investigate the antileishmanial activity of extracts from leaves and stems of seven Brazilian plant species used by the population to treat leishmaniasis, and symptoms that might be related to Leishmania infections. MATERIALS AND METHODS: Twenty two extracts from seven plants belonging to five different botanical families were prepared by different methods and evaluated for their effect on the viability of promastigote forms of Leishmania infantum (MHOM/BR/1967/BH46) using the resazurin-based colorimetric assay. The extracts were considered active when they inhibited the growth of promastigotes in a percentage greater than or equal to 50% at 100 and 200⯵g/mL. The active samples were further investigated to determine IC50, CC50 and SI values against promastigote forms of L. infantum. The active and non-cytotoxic extracts (SI> 10) were evaluated against amastigote forms of L. infantum. In addition, the active extracts against the amastigote forms were analyzed by TLC and HPLC, while the EtOAc extract of stems from Aspidosperma tomentosum was also evaluated by GC/MS. RESULTS: Among the twenty two extracts evaluated, two were considered active against L. infantum. The EtOH extract of leaves from Dyospiros hispida (IC50 55.48⯱â¯2.77⯵g/mL and IC50 80.63⯱â¯13.17⯵g/mL, respectively) and the EtOAc extract of stems from Aspidosperma tomentosum (IC50 9.70⯱â¯2.82⯵g/mL and IC50 15.88⯱â¯1.53⯵g/mL, respectively) inhibited significantly the growth of promastigote and amastigote forms of L. infantum. Some extracts, although active in the initial screening, were considered toxic since the SI was lower than 10. In TLC and HPLC analysis the leaf extract of Dyospiros hispida showed the presence of anthraquinones, terpenes and saponins, and in the EtOAc extract of stems from Aspidosperma tomentosum alkaloids and flavonoids were detected. In addition, in the latter extract the indole alkaloids uleine and dasycarpidone could be identified by GC/MS. CONCLUSIONS: The ethnopharmacological data of Aspidosperma tomentosum and Dyospiros hispida in part support the results found in the biological models used. Extracts of Aspidosperma tomentosum and Dyospiros hispida presented promising results against L. infantum.
Assuntos
Antiprotozoários/farmacologia , Leishmania infantum/efeitos dos fármacos , Magnoliopsida , Extratos Vegetais/farmacologia , Animais , Antiprotozoários/química , Brasil , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Leishmania infantum/crescimento & desenvolvimento , Magnoliopsida/química , Camundongos , Compostos Fitoquímicos/análise , Compostos Fitoquímicos/farmacologia , Extratos Vegetais/químicaRESUMO
Cutaneous leishmaniasis is a neglected tropical disease, causing a spectrum of clinical manifestations varying from self-healing to unhealing lesions that may be very difficult to treat. Emerging evidence points to a detrimental role for neutrophils during the first hours following infection with many distinct Leishmania species (spp.) at a time when the parasite is in its nonreplicative promastigote form. Neutrophils have also been detected at later stages of infection in unhealing chronic cutaneous lesions. However, the interactions between these cells and the replicative intracellular amastigote form of the parasite have been poorly studied. Here, we show that Leishmaniamexicana amastigotes are efficiently internalized by neutrophils and that this process has only a low impact on neutrophil activation and apoptosis. In neutrophils, the amastigotes were found in acidified vesicles. Furthermore, within cutaneous unhealing lesions, heavily infected neutrophils were found with up to 6 parasites per cell. To investigate if the amastigotes could replicate within neutrophils, we generated photoconvertible fluorescent parasites. With the use of flow cytometry imaging and time-lapse microscopy, we could demonstrate that a subset of parasites replicated within neutrophils. Overall, our data reveal a novel role for neutrophils that can act as a niche for parasite replication during the chronic phase of infection, thereby contributing to disease pathology.
Assuntos
Divisão Celular , Leishmania mexicana/crescimento & desenvolvimento , Leishmaniose Cutânea/parasitologia , Estágios do Ciclo de Vida/genética , Neutrófilos/parasitologia , Organismos Geneticamente Modificados/crescimento & desenvolvimento , Animais , Feminino , Citometria de Fluxo , Corantes Fluorescentes/metabolismo , Genes Reporter , Interações Hospedeiro-Parasita/imunologia , Leishmania mexicana/patogenicidade , Leishmania mexicana/ultraestrutura , Leishmaniose Cutânea/patologia , Camundongos , Camundongos Endogâmicos C57BL , Neutrófilos/ultraestrutura , Fagocitose , Processos Fotoquímicos , Imagem com Lapso de TempoRESUMO
With the aim to identify a potential drug candidate to treat cutaneous leishmaniasis, a series of 1-phthalazinyl hydrazones were synthesized and tested against Leishmania braziliensis parasite, one of the main responsible of this disease in the world. A structure-activity relationship permitted to identify two phthalazines containing nitroheterocyclic moiety 3l and 3m as promising new lead compounds. These compounds showed a significant antileishmanial activity against promastigote form of L. braziliensis, with EC50 values in sub-micromolar and nanomolar ranges. The phthalazine 3l also displayed a selective and excellent activity against the clinically relevant intracellular amastigotes form, with a EC50 value in sub-micromolar range (0.59 µM), without affecting the viability of the host cells. Oxidative stress was identified as the possible mode of action of the most active phthalazine. Considering their significant antileishmanial activity and ease synthesis, the phthalazine containing nitroheterocyclic represents a promising agent against Leishmania braziliensis for the rational design of new leads.
Assuntos
Antiprotozoários/síntese química , Antiprotozoários/farmacologia , Desenho de Fármacos , Hidrazonas/síntese química , Hidrazonas/farmacologia , Leishmania braziliensis/efeitos dos fármacos , Ftalazinas/química , Animais , Antiprotozoários/química , Antiprotozoários/toxicidade , Linhagem Celular , Hidrazonas/química , Hidrazonas/toxicidade , Leishmania braziliensis/enzimologia , Leishmania braziliensis/crescimento & desenvolvimento , Macrófagos/efeitos dos fármacos , Camundongos , Modelos Moleculares , Conformação Proteica , Relação Estrutura-Atividade , Superóxido Dismutase/química , Superóxido Dismutase/metabolismoRESUMO
Extracts of Serjania lethalis A. St.-Hil leaves and stems were tested in order to identify potential agents against Leishmania amazonensis. The hexane fraction (HF) and dichloromethane subfractions (DDF and MDF) showed leishmanicidal effect. The anti-promastigote IC50 values were 10.29 (HF), 11.41 (DDF) and 28.33µg/mL (MDF); whereas those against amastigote were 7.2 (HF), 8.1 (DDF) and 6.5µg/mL (MDF). Among the fractions and subfractions assayed, only HF altered the cell cycle of the parasite, increasing 3-fold the number of cells in the sub-G0/G1 phase. HF also changed the parasite mitochondrial membrane potential (ΔΨm) and the percentage of annexin-V-propidium iodide positive promastigotes. Our evaluations of the IC50 values showed that HF, DDF and MDF decreased NO production in infected macrophages stimulated with IFN-γ and LPS. Moreover, HF increased the production of TNF-α in Leishmania infected macrophages. This paper reports for the first time the leishmanicidal activity of extracts and fractions of Serjania lethalis leaves and also characterizes its leishmanicidal and immunomodulatory properties.
Assuntos
Antiprotozoários/farmacologia , Leishmania mexicana/efeitos dos fármacos , Macrófagos Peritoneais/efeitos dos fármacos , Magnoliopsida/química , Extratos Vegetais/farmacologia , Animais , Anexina A5/análise , Fase G1/efeitos dos fármacos , Hexanos/química , Imunomodulação , Concentração Inibidora 50 , Interferon gama/imunologia , Leishmania mexicana/crescimento & desenvolvimento , Leishmania mexicana/fisiologia , Lipopolissacarídeos/imunologia , Macrófagos Peritoneais/imunologia , Macrófagos Peritoneais/parasitologia , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Cloreto de Metileno/química , Camundongos , Óxido Nítrico/biossíntese , Extratos Vegetais/química , Folhas de Planta/química , Fase de Repouso do Ciclo Celular/efeitos dos fármacos , Fator de Necrose Tumoral alfa/biossínteseRESUMO
Dendritic cells (DC) are one of the principal host cells of the obligate intracellular parasite Leishmania. Inhibition of host cell apoptosis is a strategy employed by multiple pathogens to ensure their survival in the infected cell. We have previously shown that the infection of monocyte-derived dendritic cells (moDC) with Leishmania mexicana inhibits campthotecin-induced apoptosis. Nevertheless, the mechanisms involved in the inhibition of apoptosis of dendritic cells by Leishmania have not been established. Mitogen-activated protein kinases (MAPK) are key participants in the process of apoptosis and different species of Leishmania have been shown to regulate these kinases. In the present study, we analyzed the effect of L. mexicana promastigotes in the activation of JNK and p38 MAP kinase and their participation in the inhibition of apoptosis. The infection of moDC with L. mexicana promastigotes diminished significantly the phosphorylation of the MAP kinases JNK and p38. The inhibition of both kinases diminished DNA fragmentation, but in a major extent was the reduction of DNA fragmentation when JNK was inhibited. The capacity of L. mexicana promastigotes to diminish MAP kinases activation is probably one of the strategies employed to delay apoptosis induction in the infected moDC and may have implications for Leishmania pathogenesis by favoring the invasion of its host and the persistence of the parasite in the infected cells.
Assuntos
Apoptose/fisiologia , Células Dendríticas/parasitologia , Regulação para Baixo , Leishmania mexicana/fisiologia , MAP Quinase Quinase 4/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Animais , Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Camptotecina/farmacologia , Células Cultivadas , Células Dendríticas/citologia , Células Dendríticas/efeitos dos fármacos , Feminino , Humanos , Marcação In Situ das Extremidades Cortadas , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Macrófagos/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , FosforilaçãoRESUMO
Cutaneous leishmaniasis has an estimated incidence of 1.5 million new cases per year and the treatment options available are old, expensive, toxic, and difficult to administer. Chalcones have shown good activity against several species of Leishmania. However few studies have discussed the mechanisms of action and drug target of this group of compounds in Leishmania. The synthetic chalcones that were evaluated in the present study were previously shown to exhibit activity against Leishmania (Viannia) braziliensis. The objective of the present study was to identify ultrastructural and morphological changes in L. (V.) braziliensis after treatment with three synthetic chalcones (1-3). Promastigotes were treated with chalcones 1-3 and evaluated by transmission and scanning electron microscopy. Cellular and nuclear morphology of the parasites, changes in membrane permeability, and DNA fragmentation in agarose electrophoresis gel were also investigated after exposure to synthetic chalcones. All three synthetic chalcones (1-3) induced ultrastructural alterations in mitochondria, intense vacuolization, two nuclei with rounding of parasites, and cellular and nuclear shrinkage. Chalcones 1-3 also induced no changes in membrane permeability, and presence of nucleosome-sized DNA fragments. Synthetic chalcones 1-3 induced ultrastructural and morphological changes, suggesting that chalcones 1-3 induce apoptosis-like cell death. Further studies should be conducted to elucidate other aspects of the action of these chalcones against Leishmania spp. and their use for the treatment of cutaneous leishmaniasis.
Assuntos
Chalconas/farmacologia , Leishmania braziliensis/efeitos dos fármacos , Animais , Apoptose , Permeabilidade da Membrana Celular/efeitos dos fármacos , Núcleo Celular/efeitos dos fármacos , Chalconas/síntese química , Cricetinae , Fragmentação do DNA/efeitos dos fármacos , Marcação In Situ das Extremidades Cortadas , Leishmania braziliensis/ultraestrutura , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Mitocôndrias/efeitos dos fármacos , Vacúolos/efeitos dos fármacosRESUMO
A series of eleven 3,4-methylenedioxyde-6-X-benzaldehyde-thiosemicarbazones (16-27) was synthesised as part of a study to search for potential new drugs with a leishmanicidal effect. The thiosemicarbazones, ten of which are new compounds, were prepared in good yields (85-98%) by the reaction of 3,4-methylenedioxyde-6-benzaldehydes (6-X-piperonal), previously synthesised for this work by several methodologies, and thiosemicarbazide in ethanol with a few drops of H2SO4. These compounds were evaluated against Leishmania amazonensis promastigotes, and derivatives where X = I (22) and X = CN (23) moieties showed impressive results, having IC50 = 20.74 µM and 16.40 µM, respectively. The intracellular amastigotes assays showed IC50 = 22.00 µM (22) and 17.00 µM (23), and selectivity index >5.7 and >7.4, respectively, with a lower toxicity compared to pentamidine (positive control, SI = 4.5). The results obtained from the preliminary QSAR study indicated the hydrophobicity (log P) as a fundamental parameter for the 2D-QSAR linear model. A molecular docking study demonstrated that both compounds interact with flavin mononucleotide (FMN), important binding site of NO synthase.
Assuntos
Antiprotozoários/síntese química , Antiprotozoários/farmacologia , Benzodioxóis/farmacologia , Leishmania/efeitos dos fármacos , Tiossemicarbazonas/farmacologia , Antiprotozoários/química , Benzodioxóis/síntese química , Benzodioxóis/química , Relação Dose-Resposta a Droga , Estrutura Molecular , Testes de Sensibilidade Parasitária , Relação Estrutura-Atividade , Tiossemicarbazonas/síntese química , Tiossemicarbazonas/químicaRESUMO
Current treatments for leishmaniasis present some difficulties due to their toxicity, the use of the intravenous route for administration and therapy duration, which may lead to treatment discontinuation. The aim of this study is to investigate new treatment alternatives to improve patients well being. Therefore, we evaluated the inhibitory effect of (-)α-bisabolol, a sesquiterpene alcohol found in various essential oils of different plant species, against the promastigotes and intracellular amastigotes forms of Leishmania amazonensis, as well as the cytotoxic, morphological and ultrastructural alterations of treated cells. Promastigotes forms of L. amazonensis were incubated with (-)α-bisabolol to determine the antileishmanial activity of this compound. The cytotoxicity effect was evaluated by testing against J774.G8 cells. After these tests, the infected and uninfected cells with L. amazonensis were used to determine if the (-)α-bisabolol was able to kill intracellular parasites and to cause some morphological changes in the cells. The (-)α-bisabolol compound showed significant antileishmanial activity against promastigotes with a 50% effective concentration of 8.07 µg/ml (24 h) and 4.26 µg/ml (48 h). Against intracellular amastigotes the IC50 (inhibitory concentration) of (-)α-bisabolol (24 h) was 4.15 µg/ml. The (-)α-bisabolol also showed a cytotoxic effect against the macrophage strain J774.G8. The value of 50% cytotoxic concentration was 14.82 µg/ml showing that (-)α-bisabolol is less toxic to macrophages than to the parasite. Ultrastructural studies of treated promastigotes and amastigotes showed several alterations, such as loss of cytoplasmic organelles, including the nucleus, and the presence of lipid inclusions. This study showed that (-)α-bisabolol has promising antileishmanial properties, as it can act against the promastigote forms and is able to penetrate the cell, and is also active against the amastigote forms. About 69% of the promastigotes forms suffered mitochondrial membrane damage after treatment with IC50 of (-)α-bisabolol, suggesting inhibition of the metabolic activity of parasites. These results open new prospects for research that can contribute to the development of products based on essential oils or isolated compounds from plants for the treatment of cutaneous leishmaniasis.
Assuntos
Antiprotozoários/farmacologia , Leishmania mexicana/efeitos dos fármacos , Sesquiterpenos/farmacologia , Animais , Antiprotozoários/toxicidade , Linhagem Celular , Citometria de Fluxo , Humanos , Concentração Inibidora 50 , Leishmania mexicana/crescimento & desenvolvimento , Leishmania mexicana/ultraestrutura , Macrófagos/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Eletrônica de Transmissão , Sesquiterpenos Monocíclicos , Sesquiterpenos/toxicidadeRESUMO
Leishmaniasis is a major public health problem, and the alarming spread of parasite resistance has increased the importance of discovering new therapeutic products. The present study aimed to investigate the in vitro leishmanicidal activity from 16 different Brazilian medicinal plants. Stationary-phase promastigotes of Leishmania amazonensis and murine macrophages were exposed to 44 plant extracts or fractions for 48 h at 37°C, in order to evaluate their antileishmanial activity and cytotoxicity, respectively. The most potent extracts against L. amazonensis were the hexanic extract of Dipteryx alata (IC50 of 0.08 µg/mL), the hexanic extract of Syzygium cumini (IC50 of 31.64 µg/mL), the ethanolic and hexanic extracts of leaves of Hymenaea courbaril (IC50 of 44.10 µg/mL and 35.84 µg/mL, respectively), the ethanolic extract of H. stignocarpa (IC50 of 4.69 µg/mL), the ethanolic extract of Jacaranda caroba (IC50 of 13.22 µg/mL), and the ethanolic extract of J. cuspidifolia leaves (IC50 of 10.96 µg/mL). Extracts of D. alata and J. cuspidifolia presented higher selectivity index, with high leishmanicidal activity and low cytotoxicity in the mammalian cells. The capacity in treated infected macrophages using the extracts and/or fractions of D. alata and J. cuspidifolia was also analyzed, and reductions of 95.80%, 98.31%, and 97.16%, respectively, in the parasite burden, were observed. No nitric oxide (NO) production could be observed in the treated macrophages, after stimulation with the extracts and/or fractions of D. alata and J. cuspidifolia, suggesting that the biological activity could be due to mechanisms other than macrophage activation mediated by NO production. Based on phytochemistry studies, the classes of compounds that could contribute to the observed activities are also discussed. In conclusion, the data presented in this study indicated that traditional medicinal plant extracts present effective antileishmanial activity. Future studies could focus on the identification and purification of the antileishmanial compounds within these plants for analysis of their in vivo antileishmanial activity.
Assuntos
Antiprotozoários/farmacologia , Leishmania mexicana/efeitos dos fármacos , Macrófagos Peritoneais/efeitos dos fármacos , Extratos Vegetais/farmacologia , Plantas Medicinais/química , Animais , Antiprotozoários/toxicidade , Brasil , Feminino , Flavonoides/análise , Flavonoides/isolamento & purificação , Concentração Inibidora 50 , Leishmaniose Cutânea/tratamento farmacológico , Camundongos , Óxido Nítrico/metabolismo , Fenóis/análise , Fenóis/isolamento & purificação , Fitoterapia , Extratos Vegetais/química , Extratos Vegetais/toxicidadeRESUMO
A Leishmaniose Tegumentar Americana no Brasil é causada por uma variedade de espécies de Leishmania e uma grande diversidade destes parasitas pode ser encontrada na Região Amazônica. Revisões recentes na quimioterapia de leishmaniose enfatizam as deficiências dos agentes terapêuticos atualmente disponíveis e mostram a necessidade urgente de novos candidatos. Uma alternativa para substituir esses medicamentos são extratos naturais de Eugenia uniflora e Momordica charantia. Foram preparados extratos etanólicos das folhas de E. uniflora e M. charantia. Para os testes in vitro de Leishmania brasiliensis foram utilizadas formas promastigotas. O ensaio de citotoxicidade foi realizado com linhagens de fibroblastos. Nossos resultados indicam que E. uniflora foi eficaz contra a cepa de parasita testada, representando uma fonte alternativa de produtos naturais com atividade contra L. brasiliensis.
Cutaneous leishmaniasis is caused in Brazil by several species of the genus Leishmania and a wide variety of these protozoan parasites can be found in Brazil, mainly in the Amazon region. Recent reviews on the chemotherapy of leishmaniasis show the low effectiveness of the usual therapeutic agents, demonstrating the need for new drugs. An interesting possible alternative to the conventional drugs is offered by natural products extracted from Eugenia uniflora and Momordica charantia. Ethanol extracts were prepared from the leaves of Eugenia uniflora and Momordica charantia and assayed in vitro against Leishmania brasiliensis promastigotes and fibroblasts to assess their antileishmanial and cytotoxic activities, respectively. Our results indicate that E. uniflora was active against the parasitic forms of L. brasiliensis
Assuntos
Eugenia/toxicidade , Extratos Vegetais/administração & dosagem , Extratos Vegetais/uso terapêutico , Leishmaniose Cutânea/tratamento farmacológico , Fitoterapia , Plantas MedicinaisRESUMO
The increased incidence of visceral leishmaniasis (VL) in Brazil is due to a lack of effective disease control measures. In addition to that, no effective treatment exists for canine VL in response to synthetic drugs. Thus, the objective of this study was to evaluate the effect of the essential oils of Coriandrum sativum and Lippia sidoides, and oleoresin from Copaifera reticulata, on Leishmania chagasi promastigotes and amastigotes. We also examined the toxicity of these treatments on the murine monocyte cell line RAW 264.7. To determine the IC50 a MTT test (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) was performed on promastigotes, and an in situ ELISA assay was conducted on amastigotes. Here, we demonstrate that oleoresin from C. reticulata was effective against both promastigotes (IC50 of 7.88 µg.mL-1) and amastigotes (IC50 of 0.52 µg.mL-1), and neither of the two treatments differed significantly (p > 0.05) from pentamidine (IC50 of 2.149 µg.mL-1) and amphotericin B (IC50 of 9.754 µg.mL-1). Of the three plant oils tested, only oleoresin showed no toxicity toward monocyte, with 78.45% viability after treatment. Inhibition of promastigote and amastigote growth and the lack of cytotoxicity by C. reticulata demonstrate that oleoresin may be a viable option for analyzing the in vivo therapeutic effects of leishmanicidal plants.(AU)
O aumento na incidência da Leishmaníase Visceral (LV) no Brasil deve-se à ineficácia das medidas de controle da doença. Além disso, não há tratamento efetivo para LV canina com drogas sintéticas. Assim, o objetivo deste trabalho foi avaliar o efeito dos óleos essenciais de Coriandrum sativum e de Lippia sidoides e do óleo-resina de Copaiferareticulata sobre promastigotas e amastigotas de Leishmania chagasi e analisar o grau de toxicidade sobre células monocíticas murinas RAW 264.7. Para determinar a CI50 sobre promastigotas foi usado teste MTT (brometo de 3-[4,5-dimetil-tiazol-2-il]-2,5-difeniltetrazólio) e sobre amastigotas foi realizado imunoensaio in situ pela técnica de ELISA. Os resultados obtidos comprovaram que o óleo-resina de C. reticulata foi o mais eficaz contra as formas promastigotas (CI50 de 7,88 µg.mL-1) e amastigotas (CI50 de 0,52 µg.mL-1) e em nenhum dos dois testes diferiu do controle pentamidina que obteve CI50 de 2,149 µg.mL-1, no teste sobre promastigotas, e anfotericina B que obteve CI50 de 9,754 µg.mL-1, nos testes com amastigotas (p > 0.05). Quanto à citotoxicidade apenas o óleo-resina não apresentou toxicidade com 78,45% de monócitos viáveis. Os resultados obtidos sobre promastigotas e amastigotas e a ausência de citotoxicidade do óleo-resina de C. reticulata evidenciam que este óleo-resina pode ser viável para a análise de seus efeitos terapêuticos em testes in vivo.(AU)
Assuntos
Animais , Camundongos , Coriandrum , Fabaceae , Leishmania , Lippia , Óleos Voláteis/farmacologia , Extratos Vegetais/farmacologia , Células Cultivadas , Concentração Inibidora 50 , Monócitos/parasitologiaRESUMO
The increased incidence of visceral leishmaniasis (VL) in Brazil is due to a lack of effective disease control measures. In addition to that, no effective treatment exists for canine VL in response to synthetic drugs. Thus, the objective of this study was to evaluate the effect of the essential oils of Coriandrum sativum and Lippia sidoides, and oleoresin from Copaifera reticulata, on Leishmania chagasi promastigotes and amastigotes. We also examined the toxicity of these treatments on the murine monocyte cell line RAW 264.7. To determine the IC50 a MTT test (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) was performed on promastigotes, and an in situ ELISA assay was conducted on amastigotes. Here, we demonstrate that oleoresin from C. reticulata was effective against both promastigotes (IC50 of 7.88 µg.mL-1) and amastigotes (IC50 of 0.52 µg.mL-1), and neither of the two treatments differed significantly (p > 0.05) from pentamidine (IC50 of 2.149 µg.mL-1) and amphotericin B (IC50 of 9.754 µg.mL-1). Of the three plant oils tested, only oleoresin showed no toxicity toward monocyte, with 78.45% viability after treatment. Inhibition of promastigote and amastigote growth and the lack of cytotoxicity by C. reticulata demonstrate that oleoresin may be a viable option for analyzing the in vivo therapeutic effects of leishmanicidal plants.
O aumento na incidência da Leishmaníase Visceral (LV) no Brasil deve-se à ineficácia das medidas de controle da doença. Além disso, não há tratamento efetivo para LV canina com drogas sintéticas. Assim, o objetivo deste trabalho foi avaliar o efeito dos óleos essenciais de Coriandrum sativum e de Lippia sidoides e do óleo-resina de Copaiferareticulata sobre promastigotas e amastigotas de Leishmania chagasi e analisar o grau de toxicidade sobre células monocíticas murinas RAW 264.7. Para determinar a CI50 sobre promastigotas foi usado teste MTT (brometo de 3-[4,5-dimetil-tiazol-2-il]-2,5-difeniltetrazólio) e sobre amastigotas foi realizado imunoensaio in situ pela técnica de ELISA. Os resultados obtidos comprovaram que o óleo-resina de C. reticulata foi o mais eficaz contra as formas promastigotas (CI50 de 7,88 µg.mL-1) e amastigotas (CI50 de 0,52 µg.mL-1) e em nenhum dos dois testes diferiu do controle pentamidina que obteve CI50 de 2,149 µg.mL-1, no teste sobre promastigotas, e anfotericina B que obteve CI50 de 9,754 µg.mL-1, nos testes com amastigotas (p > 0.05). Quanto à citotoxicidade apenas o óleo-resina não apresentou toxicidade com 78,45% de monócitos viáveis. Os resultados obtidos sobre promastigotas e amastigotas e a ausência de citotoxicidade do óleo-resina de C. reticulata evidenciam que este óleo-resina pode ser viável para a análise de seus efeitos terapêuticos em testes in vivo.
Assuntos
Animais , Camundongos , Coriandrum , Fabaceae , Lippia , Leishmania/efeitos dos fármacos , Óleos Voláteis/farmacologia , Extratos Vegetais/farmacologia , Células Cultivadas , Monócitos/parasitologiaRESUMO
Physalis angulata L., Solanaceae, is an annual herb commonly used in popular medicine in many tropical and subtropical countries. P. angulata extracts contain a variety of substances, but little is known about their pharmacological activities. In this work we investigated the in vitro antileishmanial activity of seco-steroids (physalins) purified from P. angulata. Addition of physalins B, F, and G caused a concentration-dependent inhibition in the growth of L. amazonensis promastigotes, being the IC50 values were 6.8, 1.4, and 9.2 μM, respectively. Physalin D was less active and had an IC50 value of 30.5 μM. Physalins were also active in cultures of other Leishmania species (L. major, L. braziliensis, and L. chagasi). Our results demonstrate the potent antileishmanial activity of physalins in cultures of Leishmania species of the New and Old Worlds and suggest the therapeutic potential of these seco-steroids in leishmaniasis.
Physalis angulata L., Solanaceae, é uma erva anual utilizada na medicina popular em muitos países tropicais e subtropicais. Apesar dos extratos da P. angulata apresentarem uma grande variedade de substâncias, pouco é conhecido sobre a sua atividade farmacológica. Neste trabalho foi investigado a atividade antileishmania in vitro de seco-esteroides (fisalinas) purificados da P. angulata. O tratamento com as fisalinas B, F e G causou uma inibição concentração-dependente do crescimento de promastigotas de Leishmania amazonensis em cultura axênica, com valores de IC50 de 6,8, 1,4, e 9,2 μM respectivamente. A fisalina D foi menos ativa, com valores de IC50 de 30,5 μM. Foi também observada uma atividade leishmanicida em culturas de outras espécies de Leishmania (L. major, L. braziliensis e L. chagasi). Nossos resultados demonstram que as fisalinas inibem o crescimento dos promastigotas com o tratamento de espécies de Leishmania do Velho e do Novo Mundos e sugerem o potencial terapêutico destas moléculas na leishmaniose.