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Six novel tri-aryl antimony(V) hydroximato complexes (3-8) with composition [SbAr 3 (O 2 NCR)] (3: Ar = Ph, R = o-(OH)Ph, 4: Ar = Ph, R = Me, 5: Ar = Ph, R = Ph; 6: Ar = Mes, R = Me, 7: Ar = Mes, R = Ph, 8: Ar = Mes, R = o-(OH)Ph (where Ph = phenyl, Me = methyl, Mes = mesityl)), were synthesised and evaluated for anti-parasitic activity towards Leishmania major (L. major) promastigotes and amastigotes. Complexes of the form [SbAr 3 (O 2 NCR)], with the dianionic hydroximato ligand binding O,O'-bidentate to the Sb(V) centre, exist in the solid-state for the mesityl-derived complexes. In contrast, the phenyl-ligated Sb(V) complexes crystallise as the hexacoordinate, hydroxamato species [SbPh 3 (O 2 NHC(OH))], with the OH ligand derived from entrained H 2 O in the crystallisation solvent. It is found that both the aryl and hydroximato ligands are found to influence the bioactivity of the Sb(V) complexes. Complexes 3-8 exhibited varied anti-promastigote activity with IC 50 values ranging from 1.53 μM for 6 to 36.0 μM for 3, also reflected in varied anti-amastigote activity with a percentage infection range of 5.50% for 6 to 29.00% for 3 at a concentration of 10 μM. The complexes were relatively non-toxic to human fibroblasts with an IC 50 value range of 59.3 μM (7) to ≥100 μM (3-6, 8), and exhibited varied toxicity towards J774.1 A macrophages (IC 50 : 3.97 (6) to ≥100 (8) μM). All complexes showed enhanced activity compared to the parent hydroxamic acids., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Leishmaniasis is a parasitic disease spread by the bite of an infected sandfly and caused by protozoan parasites of the genus Leishmania. Currently, there is no vaccine available for leishmaniasis in humans, and the existing chemotherapy methods face various clinical challenges. The majority of drugs are limited to a few toxic compounds, with some parasite strains developing resistance. Therefore, the discovery and development of a new anti-leishmanial compound is crucial. One promising strategy involves the use of nanoparticle delivery systems to accelerate the effectiveness of existing treatments. In this study, Amphotericin B (AmB) was incorporated into functionalized carbon nanotube (f-CNT) and evaluated for its efficacy against Leishmania major in vitro and in a BALB/c mice model. The increase in footpad thickness was measured, and real-time PCR was used to quantify the parasite load post-infection. Levels of nitric oxide and cytokines IL-4 and IFN-γ were also determined. We found that f-CNT-AmB significantly reduced the levels of promastigotes and amastigotes of the Leishmania parasite. The nanoparticle showed strong anti-leishmanial activity with an IC 50 of 0.00494 ± 0.00095 mg/mL for promastigotes and EC 50 of 0.00294 ± 0.00065 mg/mL for amastigotes at 72 h post-infection, without causing harm to mice macrophages. Treatment of infected BALB/c mice with f-CNT-AmB resulted in a significant decrease in cutaneous leishmania (CL) lesion size in the foot pad, as well as reduced Leishmania burden in both lymph nodes and spleen. The levels of nitric oxide and IFN-γ significantly increased in the f-CNT-AmB treated groups. Also, our results showed that the level of IL-4 significantly decreased after f-CNT-AmB treatment in comparison to other groups. In conclusion, our results demonstrate that AmB loaded into f-CNT is significantly more effective than AmB alone in inhibiting parasite propagation and promoting a shift towards a Th1 response., (© 2024 John Wiley & Sons Ltd.)

Drug repurposing is a promising approach towards the discovery of novel treatments against Neglected Tropical Diseases, such as Leishmaniases, presenting the advantage of reducing both costs and duration of the drug discovery process. In previous work, our group developed a Machine Learning pipeline for the repurposing of FDA-approved drugs against Leishmania parasites. The present study is focused on an in vitro validation of this approach by assessing the antileishmanial effects of 10 predicted drug candidates. First, we evaluated the drugs' activity against promastigotes from two strains of L. infantum and one of L. major , which caused distinct clinical manifestations, using an MTT assay. The standard anti- Leishmania drug Amphotericin B was used as a positive control. Five molecules demonstrated anti- Leishmania effects, out of which Acebutolol, Prilocaine and Phenylephrine are described herein for the first time. When tested on promastigote growth, Acebutolol displayed IC 50 values ranging from 69.28 to 145.53 µg/mL. Prilocaine exhibited IC 50 values between 33.10 and 45.81 µg/mL. Phenylephrine, on the other hand, presented IC 50 values >200 µg/mL. The two remaining drugs, Dibucaine and Domperidone, exhibited significantly low IC 50 values varying between 0.58 and 1.05 µg/mL, and 6.30 and 8.17 µg/mL, respectively. Both compounds were previously described as anti- Leishmania agents in vivo . All five compounds demonstrated no notable cytotoxic effects on THP-1-derived macrophages at the IC 50 concentrations, allowing for their testing on the intracellular form of L. major and L. infantum parasites. Interestingly, all compounds exhibited antileishmanial activity on amastigotes with enhanced IC 50 values compared to the corresponding promastigotes. Noticeably, Dibucaine and Domperidone displayed IC 50 values of at most 1.99 µg/mL. Acebutolol, Prilocaine and Phenylephrine showed IC 50 values ranging from 13.84 to 66.81 µg/mL. Our previously published Computer-Aided repositioning pipelines of FDA-approved drugs as antileishmanial agents identified Dibucaine and Domperidone as candidates in support of previous in vivo studies. This study consolidates such findings through the in vitro validation against 2 Leishmania species, highly prevalent in Africa and Middle East, and reveals Acebutolol, Prilocaine, and Phenylephrine as novel anti- Leishmania effectors, confirming the relevance of our approach and calling for further investigations., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Oualha, Abdelkrim, Guizani and Harigua-Souiai.)

Pistacia chinensis subsp. integerrima is a valuable medicinal plant as its parts and extracts found application for treating diarrhea, fever, liver disorders, asthma, and inflammation. In this study, we report the leishmanicidal activity of sakuranetin, spinacetin, and patuletin extracted from P. chinensis . The tested compounds revealed a strong anti-leishmanial activity in vitro against Leishmania major showing IC 50 values of 7.98 ± 0.16 µM, 9.23 ± 0.23 µM 11.09 ± 0.87 µM for sakuranetin, spinacetin, and patuletin, respectively. Moreover, to explore the potential mechanism(s) by which the compounds may act, computational docking studies were performed against dihydrofolate reductase and pteridine reductase, showing that the flavonoids could target these two key enzymes to exploit their leishmanicidal activity. In accordance with in vitro results, patuletin was highlighted as the most promising compound of the set, and binding energy values of -6.72 and -6.74 kcal/mol were computed for the two proteins, respectively.

During last decades, 3,5-disubstituted-tetrahydro- 2H -thiadiazine-2-thione scaffold remains the center of interest due to their ease of preparation, diverse range substituents at N-3 and N-5 positions, and profound biological activities. In the current study, a series of 3,5-disubstituted-tetrahydro- 2H -thiadiazine-2-thiones were synthesized in good to excellent yield, and the structure of the compounds were confirmed by various spectroscopic techniques such as FTIR, 1 H-NMR, 13 C-NMR and Mass spectrometry, and finally evaluated against Leishmania major . Whereas, all the evaluated compounds (1-33), demonstrate potential leishmanicidal activities with IC 50 values in the range of (1.30- 149.98 uM). Among the evaluated compounds such as 3, 4, 6, and 10 exhibited excellent leishmanicidal activities with IC 50 values of (2.17 μM), (2.39 μM), (2.00 μM), and (1.39 μM), respectively even better than the standard amphotericin B (IC 50 = 0.50) and pentamidine (IC 50 = 7.52). In order to investigate binding interaction of the most active compounds, molecular docking study was conducted with Leishmania major . Further molecular dynamic simulation study was also carried out to assess the stability and correct binding of the most active compound 10, within active site of the Leishamania major . Likewise, the physiochemical properties, drug likeness, and ADMET of the most active compounds were investigated, it was found that none of the compounds violate Lipiniski's rule of five, which show that this class of compounds had enough potential to be used as drug candidate in near future.Communicated by Ramaswamy H. Sarma.

Background: Cutaneous Leishmaniasis (CL) remains a significant public health concern, particularly in the tropical and subtropical regions. Present treatment options for CL such as Fluconazole (FLZ) face limitations, including low solubility and bioavailability. This study aimed to address these challenges by investigating the use of nano-emulsions (NEs) to enhance the efficacy of FLZ against Leishmania major(L.major)., Materials and Methods: FLZ-NEs were formulated with oleic acid, Tween-20, and ethanol using low-energy emulsification at various surfactant/co-surfactant ratios. Subsequently, a comprehensive analysis was conducted to assess the physicochemical characteristics of the samples. This analysis encompassed stability, zeta potential, pH, viscosity, refractive index, and droplet size. We then studied the anti-parasitic properties of these optimized FLZ-NEs both in vitro and in vivo., Results: The selected nano-emulsion (NE) formulation (2 % oleic acid, 20 % Tween 20, 10 % ethyl alcohol) showcased desirable properties like small droplet size (10.51 ± 0.24 nm), low dispersity (0.19 ± 0.03), and zeta potential value (- 0.41 ± 0.17 mV), key for stability and targeted drug delivery. This optimal formulation translated into remarkable efficacy. In vitro, FLZ-NEs demonstrated a threefold increase in their ability to combat promastigotes and a remarkable thirtyfold increase in their ability to combat amastigotes. Additionally, they demonstrated a ninefold advantage in their ability to specifically target parasites within infected macrophages, thereby attacking the infection site. These promising in vitro results translated into improved outcomes in vivo. Compared to other chemicals studied, FLZ-NE-treated mice showed decreased disease severity, weight growth, and quicker ulcer healing. It was further supported by histopathological research, which showed reduced tissue damage linked to Leishmania infection., Conclusion: These findings show the potential of nanotechnology-based drug delivery in improving anti-leishmanial treatment., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Currently, no safe vaccine against leishmaniasis is available. So far, different control strategies against numerous reservoir hosts and biological vectors have not been environment-friendly and feasible. Hence, employing medicinal components and conventional drugs could be a promising approach to developing novel therapeutic alternatives. This study aimed to explore diallyl sulfide (DAS), a dynamic constituent of garlic, alone and in a mixture with meglumine antimoniate (MAT as standard drug) using in vitro and animal model experiments against Leishmania major stages. The binding affinity of DAS and four major defense elements of the immune system (iNOS, IFN-ɣ, IL-12, and TNF-α) was used to predict the predominant binding mode for molecular docking configurations. Herein, we conducted a broad range of experiments to monitor and assess DAS and MAT potential treatment outcomes. DAS, combined with MAT, displayed no cytotoxicity and employed a powerful anti-leishmanial activity, notably against the clinical stage. The function mechanism involved immunomodulation through the induction of Th1 cytokine phenotypes, triggering a high apoptotic profile, reactive oxygen species (ROS) production, and antioxidant enzymes. This combination significantly decreased cutaneous lesion diameter and parasite load in BALB/c mice. The histopathological findings performed the infiltration of inflammatory cells associated with T-lymphocytes, particularly CD4+ phenotypes, as determined by biochemical markers in alleviating the amastigote stage and improving the pathological changes in L. major infected BALB/c mice. Therefore, DAS and MAT deserve further advanced therapeutic development and should be considered as possible candidates for treating volunteer cases with cutaneous leishmaniasis in designing an upcoming clinical trial., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Zarrinkar et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Aim: We aim to develop new anti-leishmanial agents against Leishmania major and Leishmania tropica . Materials & methods: A total of 23 thiourea derivatives of (±)-aminoglutethimide were synthesized and evaluated for in vitro activity against promastigotes of L. major and L. tropica . Results & conclusion: The N -benzoyl analogue 7p was found potent (IC 50  = 12.7 μM) against L. major and non toxic to normal cells. The docking studies, indicates that these inhibitors may target folate and glycolytic pathways of the parasite. The N -hexyl compound 7v was found strongly active against both species, and lacked cytotoxicity against normal cells, whereas compound 7r , with a 3,5-bis-(tri-fluoro-methyl)phenyl unit, was active against Leishmania , but was cytotoxic in nature. Compound 7v was thus identified as a hit for further studies.

Leishmania major is responsible for zoonotic cutaneous leishmaniasis. Therapy is mainly based on the use of antimony-based drugs; however, treatment failures and illness relapses were reported. Although studies were developed to understand mechanisms of drug resistance, the interactions of resistant parasites with their reservoir hosts and vectors remain poorly understood. Here we compared the development of two L. major MON-25 trivalent antimony-resistant lines, selected by a stepwise in vitro Sb(III)-drug pressure, to their wild-type parent line in the natural vector Phlebotomus papatasi. The intensity of infection, parasite location and morphological forms were compared by microscopy. Parasite growth curves and IC 50 values have been determined before and after the passage in Ph. papatasi. qPCR was used to assess the amplification rates of some antimony-resistance gene markers. In the digestive tract of sand flies, Sb(III)-resistant lines developed similar infection rates as the wild-type lines during the early-stage infections, but significant differences were observed during the late-stage of the infections. Thus, on day 7 p. i., resistant lines showed lower representation of heavy infections with colonization of the stomodeal valve and lower percentage of metacyclic promastigote forms in comparison to wild-type strains. Observed differences between both resistant lines suggest that the level of Sb(III)-resistance negatively correlates with the quality of the development in the vector. Nevertheless, both resistant lines developed mature infections with the presence of infective metacyclic forms in almost half of infected sandflies. The passage of parasites through the sand fly guts does not significantly influence their capacity to multiply in vitro. The IC 50 values and molecular analysis of antimony-resistance genes showed that the resistant phenotype of Sb(III)-resistant parasites is maintained after passage through the sand fly. Sb(III)-resistant lines of L. major MON-25 were able to produce mature infections in Ph. papatasi suggesting a possible circulation in the field using this vector., Competing Interests: Declaration of competing interest The authors declare that there is no conflict of interest regarding the publication of this article., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Encephalitozoon intestinalis is an opportunistic microsporidian parasite that primarily infects immunocompromised individuals, such as those with HIV/AIDS or undergoing organ transplantation. Leishmaniasis is responsible for parasitic infections, particularly in developing countries. The disease has not been effectively controlled due to the lack of an effective vaccine and affordable treatment options. Current treatment options for E. intestinalis infection and leishmaniasis are limited and often associated with adverse side effects. There is no previous study in the literature on the antimicrosporidial activities of Ag(I)-N-heterocyclic carbene compounds. In this study, the in vitro antimicrosporidial activities of previously synthesized Ag(I)-N-heterocyclic carbene complexes were evaluated using E. intestinalis spores cultured in human renal epithelial cell lines (HEK-293). Inhibition of microsporidian replication was determined by spore counting. In addition, the effects of the compounds on Leishmania major promastigotes were assessed by measuring metabolic activity or cell viability using a tetrazolium reaction. Statistical analysis was performed to determine significant differences between treated and control groups. Our results showed that the growth of E. intestinalis and L. major promastigotes was inhibited by the tested compounds in a concentration-dependent manner. A significant decrease in parasite viability was observed at the highest concentrations. These results suggest that the compounds have potential anti-microsporidial and anti-leishmanial activity. Further research is required to elucidate the underlying mechanisms of action and to evaluate the efficacy of the compounds in animal models or clinical trials., (© 2024. The Author(s).)

Several G-quadruplex nucleic acid (G4s) ligands have been developed seeking target selectivity in the past decade. Naphthalene diimide (NDI)-based compounds are particularly promising due to their biological activity and red-fluorescence emission. Previously, we demonstrated the existence of G4s in the promoter region of parasite genomes, assessing the effectiveness of NDI-derivatives against them. Here, we explored the biological activity of a small library of G4-DNA ligands, exploiting the NDI pharmacophore, against both Trypanosoma brucei and Leishmania major parasites. Biophysical and biological assays were conducted. Among the various families analyzed, core-extended NDIs exhibited the most promising results concerning the selectivity and antiparasitic effects. NDI 16 emerged as the most potent, with an IC 50 of 0.011 nM against T. brucei and remarkable selectivity vs MRC-5 cells (3454-fold). Fascinating, 16 is 480-fold more potent than the standard drug pentamidine (IC 50 = 5.3 nM). Cellular uptake and parasite localization were verified by exploiting core-extended NDI red-fluorescent emission.

The present study aimed to assess the anti-leishmanial effects of curcumin nanoemulsion (CUR-NE) against Leishmania major (MRHO/IR/75/ER) in both in vitro and in vivo experiments. CUR-NE was successfully prepared via the spontaneous emulsification method. The in vitro effect of various concentrations of CUR-NE against L. major promastigotes was assessed using the flow cytometry method. In vivo experiments were carried out in BALB/c mice inoculated subcutaneously with 2 × 10 6  L. major promastigotes. Mice were treated with topical CUR-NE (2.5 mg/ml), intra-lesion injection of CUR-NE (2.5 mg/ml), topical CUR suspension (CUR-S, 2.5 mg/ml), topical NE without CUR (NE-no CUR), amphotericin B as the positive control group, and infected untreated mice as the negative control group. In vitro exposure of promastigotes to CUR-NE showed a dose-dependent anti-leishmanial effect, with a 67.52 ± 0.35% mortality rate at a concentration of 1250 µg/ml and an IC50 of 643.56 µg/ml. In vivo experiments showed that topical CUR-NE and CUR-S significantly decreased the mean lesion size in mice after four weeks from 4.73 ± 1.28 to 2.78 ± 1.28 mm and 4.45 ± 0.88 to 3.23 ± 0.59 mm, respectively (p = 0.001). Furthermore, CUR-NE significantly decreased the parasite load in treated mice compared with the negative control group (p = 0.001). Results from the current study demonstrated the promising activity of CUR-NE against L. major in both in vitro and in vivo experiments. Moreover, CUR-NE was more efficient than CUR-S in healing and reducing parasite burden in mouse models. Future studies should aim to identify molecular mechanisms as well as the pharmacologic and pharmacokinetic aspects of CUR-NE., (© 2024. The Author(s).)

Leishmaniasis is a neglected tropical disease; there is currently no vaccine and treatment is reliant upon a handful of drugs suffering from multiple issues including toxicity and resistance. There is a critical need for development of new fit-for-purpose therapeutics, with reduced toxicity and targeting new mechanisms to overcome resistance. One enzyme meriting investigation as a potential drug target in Leishmania is M17 leucyl-aminopeptidase (LAP). Here, we aimed to chemically validate LAP as a drug target in L. major through identification of potent and selective inhibitors. Using RapidFire mass spectrometry, the compounds DDD00057570 and DDD00097924 were identified as selective inhibitors of recombinant Leishmania major LAP activity. Both compounds inhibited in vitro growth of L. major and L. donovani intracellular amastigotes, and overexpression of Lm LAP in L. major led to reduced susceptibility to DDD00057570 and DDD00097924, suggesting that these compounds specifically target Lm LAP. Thermal proteome profiling revealed that these inhibitors thermally stabilized two M17 LAPs, indicating that these compounds selectively bind to enzymes of this class. Additionally, the selectivity of the inhibitors to act on Lm LAP and not against the human ortholog was demonstrated, despite the high sequence similarities LAPs of this family share. Collectively, these data confirm Lm LAP as a promising therapeutic target for Leishmania spp. that can be selectively inhibited by drug-like small molecules.

Cutaneous leishmaniasis is the most prevalent form of leishmaniasis worldwide. Although various anti-leishmanial regimens have been considered, due to the lack of efficacy or occurrence of adverse reactions, design and development of novel topical delivery systems would be essential. This study aimed to prepare artemether (ART)-loaded niosomes and evaluate their anti-leishmanial effects against Leishmania major. ART-loaded niosomes were prepared through the thin-film hydration technique and characterized in terms of particle size, zeta potential, morphology, differential scanning calorimetry, drug loading, and drug release. Furthermore, anti-leishmanial effect of the preparation was assessed in vitro and in vivo. The prepared ART-loaded niosomes were spherical with an average diameter of about 100 and 300 nm with high encapsulation efficiencies of > 99%. The results of in vitro cytotoxicity revealed that ART-loaded niosomes had significantly higher anti-leishmanial activity, lower general toxicity, and higher selectivity index (SI). Half-maximal inhibitory concentration (IC50) values of ART, ART-loaded niosomes, and liposomal amphotericin B were 39.09, 15.12, and 20 µg/mL, respectively. Also, according to the in vivo study results, ART-loaded niosomes with an average size of 300 nm showed the highest anti-leishmanial effects in animal studies. ART-loaded niosomes would be promising topical drug delivery system for the management of cutaneous leishmaniasis., (© 2024. The Author(s).)

Currently, zinc oxide (ZnO) particles are used in nanotechnology to destroy a wide range of microorganisms. Although pentavalent antimony compounds are used as antileishmanial drugs, they are associated with several limitations and side effects. Therefore, it is always desirable to try to find new and effective treatments. The aim of this research is to determine the antileishmanial effect of ZnO particles in comparison to the Antimoan Meglumine compound on promastigotes and amastigotes of Leishmania major (MRHO/IR/75/ER). After the extraction and purification of macrophages from the peritoneal cavity of C57BL/6 mice, L. major parasites were cultured in Roswell Park Memorial Institute-1640 culture medium containing fetal bovine serum (FBS) 10% and antibiotic. In this experimental study, the effect of different concentrations of nanoparticles was investigated using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) colorimetric method, in comparison to the glucantime on promastigotes, amastigotes and healthy macrophages in the culture medium. The amount of light absorption of the obtained color from the regeneration of tetrazolium salt to the product color of formazan by the parasite was measured by an enzyme-linked immunosorbent assay (ELISA) reader, and the IC 50 value was calculated. IC 50 after 24 h of incubation was calculated as IC 50  = 358.6 µg/mL. The results showed, that the efficacy of ZnO nanoparticles was favorable and dose-dependent. The concentration of 500 µg/mL of ZnO nanoparticles induced 84.67% apoptosis after 72. Also, the toxicity of nanoparticles was less than the drug. Nanoparticles exert their cytotoxic effects by inducing apoptosis. They can be suitable candidates in the pharmaceutical industry in the future., (© 2024 Wiley‐VCH GmbH.)

Leishmaniasis and Human African trypanosomiasis pose significant public health threats in resource-limited regions, accentuated by the drawbacks of the current antiprotozoal treatments and the lack of approved vaccines. Considering the demand for novel therapeutic drugs, a series of BODIPY derivatives with several functionalizations at the meso , 2 and/or 6 positions of the core were synthesized and characterized. The in vitro activity against Trypanosoma brucei and Leishmania major parasites was carried out alongside a human healthy cell line (MRC-5) to establish selectivity indices (SIs). Notably, the meso -substituted BODIPY, with 1-dimethylaminonaphthalene ( 1b ) and anthracene moiety ( 1c ), were the most active against L. major , displaying IC 50 = 4.84 and 5.41 μM, with a 16 and 18-fold selectivity over MRC-5 cells, respectively. In contrast, the mono-formylated analogues 2b and 2c exhibited the highest toxicity (IC 50 = 2.84 and 6.17 μM, respectively) and selectivity (SI = 24 and 11, respectively) against T. brucei . Further insights on the activity of these compounds were gathered from molecular docking studies. The results suggest that these BODIPYs act as competitive inhibitors targeting the NADPH/NADP + linkage site of the pteridine reductase (PR) enzyme. Additionally, these findings unveil a range of quasi-degenerate binding complexes formed between the PRs and the investigated BODIPY derivatives. These results suggest a potential correlation between the anti-parasitic activity and the presence of multiple configurations that block the same site of the enzyme.

Israel is endemic for Old-World cutaneous leishmaniasis. The most common species is Leishmania major. However, the available treatment options are limited. This study's objective was to compare the authors' experience with different antimony intralesional treatments of Leishmania major cutaneous leishmaniasis. A retrospective evaluation was undertaken for cases of Leishmania major cutaneous leishmaniasis treated by pentavalent antimony in a university-affiliated medical centre in Israel. The previous treatment of intralesional sodium stibogluconate (Pentostam®) was compared with the current treatment of meglumine antimoniate (Glucantime®). One hundred cases of cutaneous leishmaniasis were treated during the study period, of whom 33 were treated with intralesional sodium stibogluconate and 67 were treated with intralesional meglumine antimoniate. The patients were 78 males and 22 females, mean age 24 (range 10-67) and there was a total of 354 skin lesions. Within 3 months from treatment, 91% (30/33) of the intralesional sodium stibogluconate group and 88% (59/67) of the intralesional meglumine antimoniate group had complete healing of the cutaneous lesions after an average of 3 treatment cycles (non-statistically significant). In conclusion, the 2 different medications have the same efficacy and safety for treating cutaneous leishmaniasis. Pentavalent antimoniate intralesional infiltration treatment is safe, effective, and well tolerated with minimal side effects for Old-World cutaneous leishmaniasis.

Cutaneous leishmaniasis is a neglected disease prevalent in tropical countries, and conventional treatment can cause several serious side effects. Photodynamic therapy (PDT) can be considered a promising treatment alternative, as it is non-invasive therapy that has no side effects and uses accessible and low-cost substances, such as curcumin. This study evaluated the PDT response with cationic and anionic BSA nanoparticles encapsulated with curcumin in macrophages infected with L. braziliensis, L. major, and L. amazonensis. The nanoparticle system was characterized using a steady-state technique, scanning electron microscopy (SEM) study, and its biological activity was evaluated using macrophage cell lines infected with different Leishmania species. All spectroscopy measurements demonstrated that BSA curcumin (BSACur) has good photophysical properties, and confocal microscopy shows that macrophages and protozoa internalized the nanoparticles. The viability test demonstrated that at low concentrations, such as 0.1, 0.7, and 1.0 µmol. L -1 , there was a decrease in cell viability after PDT application. Furthermore, a decrease in the number of parasites recovered was observed in the PDT groups. The results allowed us to conclude that curcumin loaded into BSA nanoparticles may have potential application in drug delivery systems for PDT protocols, demonstrating reduced cell viability at lower concentrations than free curcumin., Competing Interests: Declaration of competing interest The author declares no conflict of interest., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Introduction: Leishmaniasis is a neglected disease with high prevalence and incidence in tropical and subtropical areas. Existing drugs are limited due to cost, toxicity, declining efficacy and unavailability in endemic places. Drug repurposing has established as an efficient way for the discovery of drugs for a variety of diseases., Purpose: The objective of the present work was testing the antileishmanial activity of thioridazine, an antipsychotic agent with demonstrated effect against other intracellular pathogens., Methods: The cytotoxicity for mouse peritoneal macrophages as well as the activity against Leishmania amazonensis, Leishmania mexicana and Leishmania major promastigotes and intracellular amastigotes, as well as in a mouse model of cutaneous leishmaniasis, were assessed., Results: Thioridazine inhibited the in vitro proliferation of promastigotes (50% inhibitory concentration-IC 50 -values in the range of 0.73 µM to 3.8 µM against L. amazonensis, L. mexicana and L. major) and intracellular amastigotes (IC 50 values of 1.27 µM to 4.4 µM for the same species). In contrast, in mouse peritoneal macrophages, the 50% cytotoxic concentration was 24.0 ± 1.89 µM. Thioridazine inhibited the growth of cutaneous lesions and reduced the number of parasites in the infected tissue of mice. The dose of thioridazine that inhibited lesion development by 50% compared to controls was 23.3 ± 3.1 mg/kg and in terms of parasite load, it was 11.1 ± 0.97 mg/kg., Conclusions: Thioridazine was effective against the promastigote and intracellular amastigote stages of three Leishmania species and in a mouse model of cutaneous leishmaniasis, supporting the potential repurposing of this drug as an antileishmanial agent., (© 2023. The Author(s).)

Leishmaniasis causes significant morbidity and mortality worldwide. In our country, there has been a significant increase in the number of cases of leishmaniasis in the last decade. In our study, the effects of Hypericum thymbrifolium, Hypericum scabrum and Eryngium creticum plant extracts were tested on Leishmania major, Leishmania tropica and Leishmania infantum/donovani, which were clinically resistant by not responding to Glucantime® therapy. Cytotoxicity of these extracts were evaluated by XTT method in the human fibroblast cell line. Possible active ingredients were detected by GC-MS analysis from plant extracts. Glucantime® resistance was detected at concentrations of 50 µg/mL and lower in 4 of the 7 strains tested. No living leishmania parasites were found in leishmania strains treated with plant extracts at concentrations of 100 µg/mL or higher. The concentrations of plant extracts included in the study on the WI-38 human fibroblast cell line were not cytotoxic. According to the GC-MS analysis, several active substances with biological activities and anti-parasitic effects, such as Thiophene, Germacrene-D, trans-Geranylgeraniol, Pyridine, and Maleimides, were identified. Based on the findings of the study, it is believed that these identified active substances when supported by in-vivo studies, will pave the way for future research and have the potential to be developed as anti-leishmania drugs.

Introduction: Fumaria has been traditionally used to treat skin damages due to anti-inflammatory properties. In the present study, we evaluated the effect of the ethanolic extract of Fumaria parviflora Lam. (F. parviflora) against Leishmania major (L. major) using chitosan biopolymer drug delivery system both In vitro and In vivo models., Materials and Methods: The ethanolic extract of F. parviflora was analyzed by HPLC to determine its active ingredients content. The extract was then loaded on chitosan nanoparticles (CNPs). The parasite was treated with various concentrations of the ethanolic extract, CNPs and CNPs loaded with F. parviflora extract (CNPs@ F. parviflora). The size of lesions of treated mice were measured on a weekly basis. The parasite burden was evaluated 8 weeks after treatment., Results: The HPLC analysis showed the presence of Fumaric acid at a high concentration. The percentage of the drug released from CNPs@ F. parviflora within 24 and 72 h were 65% and 90% respectively. The results showed that F. parviflora extract and CNPs@ F. parviflora caused 84% and 96% growth inhibition of L. major promastigotes as revealed by Neubauer chamber counting and MTT test respectively. The IC50 values of F. parviflora extract and CNPs@ F. parviflora were 450 and 68.4 µg/ml respectively. In amastigote assay, the best results showed in CNPs@ F. parviflora that only 2% of macrophages were infected with amastigotes. In vivo experiments for mice treated with F. parviflora and CNPs @ F. parviflora in comparison to control group showed a significant reduction (P < 0.05) in the mean diameter of the lesions (2.3 and 1.72 mm and 9.91 mm respectively)., Conclusion: The ethanolic extract of F. parviflora both as standalone and loaded in CNPs showed promising inhibitory effects against L. major both upon In vitro and In vivo experimentation as well as therapeutic effects for wound healing in infected mice., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Background: Cutaneous leishmaniasis is among the neglected diseases in the world. Pentavalent antimonial compounds are considered the first-line treatment for this disease. However, using alternative natural products has received great attention due to the side effects of chemical drugs and drug resistance of the Leishmania parasite. The present study aims to investigate the effect of Satureja khuzestanica essential oil (SKEO) on MDR1 gene expression., Methods: In this study, standard strains of Leishmania major promastigotes were exposed to 5, 10, 15, and 20 µg/ml of SKEO. MDR1 gene expression of parasites exposed to essential oil was evaluated using real-time PCR. GAPDH was employed as the housekeeping gene for internal control., Results: Despite the increase, no statistically significant difference was observed in the relative expression of the MDR1 gene between the control group and the groups containing 5, 10, and 20 µg/ml of SKEO (P > 0.05). The relative expression of the MDR1 gene significantly increased in the group containing 15 μg/ml of essential oil compared to the control one (P < 0.05)., Conclusion: This study showed that the use of essential oil of Satureja khuzestanica plant can have an increasing effect on the expression of MDR1 gene of Leishmania promastigotes, which is the best case if Satureja khuzestanica essential oil reduces the expression of MDR1 gene. So it seems that the use of essential oil of Satoria plant is effective in controlling Leishmania parasite, but its concentrations induce drug resistance. As a result, concentrations of essential oil should be used that have a controlling effect on the growth and proliferation of Leishmania parasite and also have the least effect on the induction of MDR1 gene expression., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Hydrazones 1-6, azo-pyrazoles 7-9 and azo-pyrimidines 10-15 are compounds that exhibit antibacterial activity. The mode of action and structures of these derivatives have been previously confirmed as antibacterial. In this investigation, biological screening and molecular docking studies were performed for derivatives 1-15, with compounds 2, 7, 8, 14 and 15 yielding the best energy scores (from -20.7986 to -10.5302 kcal/mol). Drug-likeness and in silico ADME prediction for the most potent derivatives, 2, 7, 8, 14 and 15, were predicted (from 84.46 to 96.85%). The latter compounds showed good recorded physicochemical properties and pharmacokinetics. Compound 8 demonstrated the strongest inhibition, which was similar to the positive control (eflornithine) against Trypanosoma brucei brucei (WT), with an EC 50 of 25.12 and 22.52µM, respectively. Moreover, compound 14 exhibited the best activity against Leishmania mexicana promastigotes and Leishmania major promastigotes (EC 50 =46.85; 40.78µM, respectively).

Derivatives with tetrahydrobenzo[h]quinoline chemotype were synthesized via one-pot reactions and evaluated for their antileishmanial, antimalarial and antitubercular activities. Based on a structure-guided approach, they were designed to possess antileishmanial activity through antifolate mechanism, via targeting Leishmania major pteridine reductase 1 (Lm-PTR1). The in vitro antipromastigote and antiamastigote activity are promising for all candidates and superior to the reference miltefosine, in a low or sub micromolar range of activity. Their antifolate mechanism was confirmed via the ability of folic and folinic acids to reverse the antileishmanial activity of these compounds, comparably to Lm-PTR1 inhibitor trimethoprim. Molecular dynamics simulations confirmed a stable and high potential binding of the most active candidates against leishmanial PTR1. For the antimalarial activity, most of the compounds exhibited promising antiplasmodial effect against P. berghei with suppression percentage of up to 97.78%. The most active compounds were further screened in vitro against the chloroquine resistant strain P. falciparum, (RKL9) and showed IC 50 value range of 0.0198-0.096 μM, compared to IC 50 value of 0.19420 μM for chloroquine sulphate. Molecular docking of the most active compounds against the wild-type and quadruple mutant pf DHFR-TS structures rationalized the in vitro antimalarial activity. Some candidates showed good antitubercular activity against sensitive Mycobacterium tuberculosis in a low micromolar range of MIC, compared to 0.875 μM of isoniazid. The top active ones were further tested against a multidrug-resistant strain (MDR) and extensively drug-resistant strain (XDR) of Mycobacterium tuberculosis. Interestingly, the in vitro cytotoxicity test of the best candidates displayed high selectivity indices emphasizing their safety on mammalian cells. Generally, this work introduces a fruitful matrix for new dual acting antileishmanial-antimalarial chemotype graced with antitubercular activity. This would help in tackling drug-resistance issues in treating some Neglected Tropical Diseases., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

Leishmaniasis caused by the protozoan Leishmania presents a severe illness, principally in tropical and subtropical areas. Antileishmanial metal complexes, like Glucantime® ️ with proven activity, are routinely studied to probe their potency. We investigated the effects of a Cu (II) homoleptic complex coordinated by two dimethyl-bipyridine ligands against Leishmania major stages in silico and in vitro. The affinity of this heterocyclic Cu (II) complex (CuDMBP) towards a parasitic metacaspase was studied by molecular docking. Key pharmacokinetic and pharmacodynamic properties of the complex were predicted using three web-based tools. CuDMBP was tested for in vitro antileishmanial activities using MTT assay, model murine macrophages, flow cytometry, and quantitative real-time polymerase chain reaction (qPCR). Molecular docking confirmed the tendency between the target macromolecule and the complex. ADMET evaluations highlighted CuDMBP's key pharmacological features, including P-glycoprotein-associated GI absorption and lack of trans-BBB permeability. MTT showed significant inhibitory effects against promastigotes. CuDMBP significantly increased the level of cellular IL-12 expression (p < 0.05), while the upregulation observed in the expression of iNOS was considered not significant (p > 0.05). It decreased the expression of IL-10 significantly (p < 0.05). Findings demonstrated that CuDMBP deserves to be introduced as a leishmanicidal candidate provided further studies are carried out., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Bagher Amirheidari reports financial support was provided by Kerman University of Medical Sciences., (Copyright © 2023. Published by Elsevier Inc.)

Leishmaniasis is an infectious disease caused by obligate intracellular protozoa of the genus Leishmania with high infection and death rates in developing countries. New drugs with better pharmacological performance with regards to safety, efficacy, toxicity, and drug resistance than those/the ones currently used are urgently needed. Trypanothione synthetase (TryS) is an attractive target for the development of drugs against leishmaniasis because it is specific and essential to kinetoplastid parasites. In this study, Leishmaniamajor TryS was expressed and purified, and the kinetic parameters of purified TryS were determined. To identify novel inhibitors of LmTryS, a high-throughput screening (HTS) assay was developed and used to screen a library of 35,040 compounds. In the confirmatory assay, 42 compounds displayed half maximal inhibitory concentration (IC 50 ) values < 50 μM and six of them corresponded to novel structures with IC 50 ranging from 9 to 19 μM against LmTryS enzyme activity. Of the six inhibitors, TS001 showed the highest activity against growth of L. major promastigotes, L. donovani promastigotes, and Trypanosoma brucei brucei Lister 427 with IC 50 values of 17, 26, and 31 μM, respectively. An in silico docking study using a homology model of LmTryS predicted the molecular interactions between LmTryS and the inhibitors., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2022. Published by Elsevier Inc.)

An efficient pathway was disclosed for the synthesis of 3-chloro-6-nitro-1 H -indazole derivatives by 1,3-dipolar cycloaddition on dipolarophile compounds 2 and 3 . Faced the problem of separation of two regioisomers, a click chemistry method has allowed us to obtain regioisomers of triazole-1,4 with good yields from 82 to 90% were employed. Also, the antileishmanial biological potency of the compounds was achieved using an MTT assay that reported compound 13 as a promising growth inhibitor of Leishmania major . Molecular docking demonstrated highly stable binding with the Leishmania trypanothione reductase enzyme and produced a network of hydrophobic and hydrophilic interactions. Molecular dynamics simulations were performed for TryR- 13 complex to understand its structural and intermolecular affinity stability in a biological environment. The studied complex remained in good equilibrium with a structure deviation of ∼1-3 Å. MM/GBSA binding free energies illustrated the high stability of TryR- 13 complex. The studied compounds are promising leads for structural optimisation to enhance the antileishmanial activity.

Cutaneous leishmaniasis (CL) is a major health problem in over 98 countries of the world, including Pakistan. The current treatments are associated with a number of adverse effects and availability problem of drugs. Therefore, there is an urgent need of easily available and cost effective treatments of CL- in Pakistan. The bioassay-guided fractionation and purification of crude extract of Physalis minima has led to the isolation of a new aminophysalin B (1), and eight known physalins, physalin B (2), 5ß,6ß-epoxyphysalin B (3), 5α-ethoxy-6ß-hydroxy-5,6-dihydrophysalin B (4), physalin H (5), 5ß,6ß-epoxyphysalin C (6), and physalin G (7), K (8), and D (9). It is worth noting that compound 1 is the second member of aminophysalin series, whereas compound 6 was fully characterized for the first time. The structures of compounds 1-9 were elucidated by spectroscopic techniques Whereas, the structural assignments of compounds 1 and 8 were also supported by single-crystal X-ray diffraction studies. The anti-leishmanial activity of isolated physlains 1-9 was evaluated against Leishmania major and Leishmania tropica promastigotes. Compounds 2, 3, and 5-7 (IC50 = 9.59 ± 0.27-23.76 ± 1.10 μM) showed several-fold more potent activity against L. tropca than tested drug miltefosine (IC50 = 42.75 ± 1.03 μm) and pentamidine (IC50 = 27.20 ± 0.01 μM). Whereas compounds 2, 3 and 5 (IC50 = 3.04 ± 1.12-3.76 ± 0.85 μM) were found to be potent anti-leishmanial agents against L. major, several fold more active than tested standard miltefosine (IC50 = 25.55 ± 1.03 μM) and pentamidine (IC50 = 27.20 ± 0.015 μM). Compounds 4 (IC50 = 74.65 ± 0.81 μM) and 7 (IC50 = 39.44 ± 0.65 μM) also showed potent anti-leishmanial ativity against the miltefosine-unresponsive L. tropica strain (MIL resistant) (miltefosine IC50 = 169.55 ± 0.78 μM). Molecular docking and predictive binding studies indicated that these inhibitors may act via targeting important enzymes of various metabolic pathways of the parasites., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2022 Bano et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

The optimization of compounds with multiple targets is a difficult multidimensional problem in the drug discovery cycle. Here, we present a systematic, multidisciplinary approach to the development of selective antiparasitic compounds. Computational fragment-based design of novel pteridine derivatives along with iterations of crystallographic structure determination allowed for the derivation of a structure-activity relationship for multitarget inhibition. The approach yielded compounds showing apparent picomolar inhibition of T. brucei pteridine reductase 1 (PTR1), nanomolar inhibition of L. major PTR1, and selective submicromolar inhibition of parasite dihydrofolate reductase (DHFR) versus human DHFR. Moreover, by combining design for polypharmacology with a property-based on-parasite optimization, we found three compounds that exhibited micromolar EC 50 values against T. brucei brucei while retaining their target inhibition. Our results provide a basis for the further development of pteridine-based compounds, and we expect our multitarget approach to be generally applicable to the design and optimization of anti-infective agents.

Background: The macrophage infectivity potentiator (Mip) protein, which belongs to the immunophilin superfamily, is a peptidyl-prolyl cis/trans isomerase (PPIase) enzyme. Mip has been shown to be important for virulence in a wide range of pathogenic microorganisms. It has previously been demonstrated that small-molecule compounds designed to target Mip from the Gram-negative bacterium Burkholderia pseudomallei bind at the site of enzymatic activity of the protein, inhibiting the in vitro activity of Mip., Objectives: In this study, co-crystallography experiments with recombinant B. pseudomallei Mip (BpMip) protein and Mip inhibitors, biochemical analysis and computational modelling were used to predict the efficacy of lead compounds for broad-spectrum activity against other pathogens., Methods: Binding activity of three lead compounds targeting BpMip was verified using surface plasmon resonance spectroscopy. The determination of crystal structures of BpMip in complex with these compounds, together with molecular modelling and in vitro assays, was used to determine whether the compounds have broad-spectrum antimicrobial activity against pathogens., Results: Of the three lead small-molecule compounds, two were effective in inhibiting the PPIase activity of Mip proteins from Neisseria meningitidis, Klebsiella pneumoniae and Leishmania major. The compounds also reduced the intracellular burden of these pathogens using in vitro cell infection assays., Conclusions: These results indicate that Mip is a novel antivirulence target that can be inhibited using small-molecule compounds that prove to be promising broad-spectrum drug candidates in vitro. Further optimization of compounds is required for in vivo evaluation and future clinical applications., (© The Author(s) 2022. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy.)

There is an urgent need for the development of new treatments against trypanosomatid parasites; the causative agents of some of the most debilitating diseases in the developing world. This work targets an interesting 6-5-6-6 fused carboline scaffold, accessing a range of substituted derivatives through stereospecific intramolecular Pictet-Spengler condensation. Modification of the cyclisation conditions allowed retention of the carbamate protecting group and gave insight into the reaction mechanism. Compounds' bioactivities were measured against T. brucei, T. cruzi, L. major and HeLa cells. We have identified promising pan-trypanocidal lead compounds based on the core scaffold, and highlight key SAR trends which will be useful for the future development of these compounds as potent trypanocidal agents., (© 2021 Wiley-VCH GmbH.)

Background: Leishmaniasis is a vector-borne disease that is endemic in the tropical and sub-tropical areas of the world. Low efficacy and high cytotoxicity of the current treatment regimens for leishmaniasis is one of the most important health problems. In this experimental study, anti-leishmanial effects of different concentrations of resveratrol and resveratrol nano-emulsion (RNE) were assessed., Methods: RNE was prepared using the probe ultra-sonication method. The cytotoxicity was evaluated using the MTT technique on the L929 cell line. The anti-leishmanial activities on promastigotes of leishmania were assessed using vital staining and infected BALB/c mice were used to assess the in vivo anti-leishmanial effects., Results: In vitro and in vivo assays revealed that all concentrations of resveratrol and RNE had valuable inhibitory effects against Leishmania major in comparison to the control group (P < 0.05). The half maximal inhibitory concentration (IC 50 ) values were calculated as 16.23 and 35.71 µg/mL for resveratrol and RNE, respectively. Resveratrol and RNE showed no cytotoxicity against the L929 cell line., Conclusions: According to the potent in vitro and in vivo anti-leishmanial activity of RNE at low concentration against L. major, we suggest that it could be a promising anti-leishmanial therapeutic against L. major in the future., (© 2022. The Author(s).)

Leishmania parasites are the causative agents of a group of neglected tropical diseases known as leishmaniasis. The molecular mechanisms employed by these parasites to adapt to the adverse conditions found in their hosts are not yet completely understood. DNA repair pathways can be used by Leishmania to enable survival in the interior of macrophages, where the parasite is constantly exposed to oxygen reactive species. In higher eukaryotes, DNA repair pathways are coordinated by the central protein kinases ataxia telangiectasia mutated (ATM) and ataxia telangiectasia and Rad3 related (ATR). The enzyme Exonuclease-1 (EXO1) plays important roles in DNA replication, repair, and recombination, and it can be regulated by ATM- and ATR-mediated signaling pathways. In this study, the DNA damage response pathways in promastigote forms of L. major were investigated using bioinformatics tools, exposure of lineages to oxidizing agents and radiation damage, treatment of cells with ATM and ATR inhibitors, and flow cytometry analysis. We demonstrated high structural and important residue conservation for the catalytic activity of the putative Lmj EXO1. The overexpression of putative Lmj EXO1 made L. major cells more susceptible to genotoxic damage, most likely due to the nuclease activity of this enzyme and the occurrence of hyper-resection of DNA strands. These cells could be rescued by the addition of caffeine or a selective ATM inhibitor. In contrast, ATR-specific inhibition made the control cells more susceptible to oxidative damage in an Lmj EXO1 overexpression-like manner. We demonstrated that ATR-specific inhibition results in the formation of extended single-stranded DNA, most likely due to EXO1 nucleasic activity. Antagonistically, ATM inhibition prevented single-strand DNA formation, which could explain the survival phenotype of lineages overexpressing Lmj EXO1. These results suggest that an ATM homolog in Leishmania could act to promote end resection by putative Lmj EXO1, and an ATR homologue could prevent hyper-resection, ensuring adequate repair of the parasite DNA., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 da Silva, Bertoldo, Naves, de Vito, Damasceno, Tosi, Machado and Pedrosa.)

Three new [nilotinins M8‒M10 ( 1 ‒ 3 )] and two known [tamarixinin A ( 4 ) and gemin D ( 5 )] ellagitannins and seven simple phenolics [gallic acid ( 6 ), methyl gallate ( 7 ), 3,4-di- O -methylgallic acid ( 8 ), ellagic acid ( 9 ), 3- O -methylellagic acid ( 10 ), methyl ferulate 3- O -sulphate ( 11 ), and 7,4'-di- O -methylkaempferol ( 12 )] were isolated from the halophytic plant Tamarix nilotica (Ehrenb.) Bunge (Tamaricaceae). Their structures were determined based on intensive spectroscopic studies and comparisons with reported data. Compounds 4 , and 6 - 8 were evaluated for their cytotoxicity against lung adenocarcinoma cell line (A549) and anti-leishmanial activity against Leishmania major . Compounds 4 , 6 and 7 showed promising cytotoxic properties against A549 (IC 50 29 ± 2.3, 10.5 ± 0.7, and 20.7 ± 1.9 μg/mL), while compounds 4 and 7 showed higher growth-inhibitory effects against L. major promastigotes (IC 50 40.5 ± 2.7 and 38.4 ± 2.5 μg/mL), as compared with the standards doxorubicin (IC 50 0.42 µg/mL) and miltefosine (IC 50 9.43 μg/mL), respectively.

Leishmania parasites are the causal agent of leishmaniasis, an endemic disease in more than 90 countries worldwide. Over the years, traditional approaches focused on the parasite when developing treatments against leishmaniasis. Despite numerous attempts, there is not yet a universal treatment, and those available have allowed for the appearance of resistance. Here, we propose and follow a host-directed approach that aims to overcome the current lack of treatment. Our approach identifies potential therapeutic targets in the host cell and proposes known drug interactions aiming to improve the immune response and to block the host machinery necessary for the survival of the parasite. We started analyzing transcription factor regulatory networks of macrophages infected with Leishmania major. Next, based on the regulatory dynamics of the infection and available gene expression profiles, we selected potential therapeutic target proteins. The function of these proteins was then analyzed following a multilayered network scheme in which we combined information on metabolic pathways with known drugs that have a direct connection with the activity carried out by these proteins. Using our approach, we were able to identify five host protein-coding gene products that are potential therapeutic targets for treating leishmaniasis. Moreover, from the 11 drugs known to interact with the function performed by these proteins, 3 have already been tested against this parasite, verifying in this way our novel methodology. More importantly, the remaining eight drugs previously employed to treat other diseases, remain as promising yet-untested antileishmanial therapies. IMPORTANCE This work opens a new path to fight parasites by targeting host molecular functions by repurposing available and approved drugs. We created a novel approach to identify key proteins involved in any biological process by combining gene regulatory networks and expression profiles. Once proteins have been selected, our approach employs a multilayered network methodology that relates proteins to functions to drugs that alter these functions. By applying our novel approach to macrophages during the Leishmania infection process, we both validated our work and found eight drugs already approved for use in humans that to the best of our knowledge were never employed to treat leishmaniasis, rendering our work as a new tool in the box available to the scientific community fighting parasites.

Curcumin (diferuloylmethane) is the main phytochemical of Curcuma longa Linn, an extract of the rhizome turmeric. For thousands of years, turmeric among other natural products has been used as a dietary spice and as a medicinal plant in Asian countries. The present study reports the leishmanicidal activity of curcumin in different concentrations (10 μM, 20 μM, 40 μM). It is also showing the effect of CM11 peptide (8 μM) alone and in combination with curcumin (10 and 20 μM) as a leishmanicidal drug. The experiments were performed with the amastigote form of Leishmania major (MRHO/IR/75/ER) in vitro and the leishmanicidal activity was analyzed after 12 and 24 h of incubation by Giemsa and DAPI staining. Further investigation was done by using semi-quantitative PCR with new designed common primer pair derived from an 18S rRNA gene belonging to the L. major and mouse, which amplified the above-mentioned gene segments simultaneously with different PCR product size. Our findings showed that curcumin had leishmanicidal activity in a dose and time-dependent manner and its lowest effective dose was at concentrations of 40 μM afetr12 h and 10 μM after 24 h. The IC 50 value of curcumin against amastigote forms of L. major was 21.12 μM and 11.77 μM after 12 and 24 h, respectively. Treatment of amastigote form with CM11 (8 μM) alone and in combination with curcumin (10 μM and 20 μM) showed less leishmanicidal activity. Interestingly, CM11 in combination with curcumin (10 μM and 20 μM) had even less leishmanicidal effect compared to curcumin alone in the same concentrations (10 μM and 20 μM). The semi-quantitative PCR analysis confirmed the data achieved by Giemsa and DAPI staining and showed that curcumin reduced the PCR product derived from amastigote form in concentration and time-dependent manner compared to the genome of the host cells., (Copyright © 2021 Elsevier Inc. All rights reserved.)

A series of the title curcuminoids with structural variance in the heteroatom of the cycloalkanone and the p-substituents of the phenyl rings were tested for their activities against Leishmania major and Toxoplasma gondii parasites. The majority of them showed high activities against both parasite forms with EC 50 values in the sub-micromolar concentration range. Bis(p-pentafluorothio)-substituted 3,5-di[(E)-benzylidene]piperidin-4-one 1b was not just noticeable antiparasitic, but also exhibited a considerable selectivity for L. major promastigotes over normal Vero cells. While derivatives differing only in the p-phenyl substituents being CF 3 or SF 5 showed similar antiparasitic activities, the cyclic ketone hub was more decisive both for the anti-parasitic activities and the selectivities for the parasites vs. normal cells. QSAR calculations confirmed the observed structure-activity relations and suggested structural variations for a further improvement of the antiparasitic activity. Docking studies based on DFT calculations revealed L. major pteridine reductase 1 as a likely molecular target protein of the title compounds., (Copyright © 2021. Published by Elsevier Inc.)

A new 3,4-difluorobenzylidene analog of curcumin, CDF, was recently reported, which demonstrated significantly enhanced bioavailability and in vivo anticancer activity compared with curcumin. For highlighting the antiparasitic behavior of CDF, we tested this compound together with its new O-methylated analog MeCDF against Leishmania major and Toxoplasma gondii parasites. Both CDF and MeCDF were tested in vitro against L. major and T. gondii. In addition, the in vitro cytotoxicity against Vero cells and macrophages was determined and selectivity indices were calculated. The DPPH radical scavenging activity assay was carried out in order to determine the antioxidant activity of the test compounds. Both compounds showed high activities against both parasite forms with EC 50 values in the (sub-)micromolar range (0.35 to 0.8 μM for CDF, 0.31 to 1.2 μM for MeCDF). The higher activity of CDF against L. major amastigotes when compared with MeCDF can in parts be attributed to the antioxidant activity of CDF while MeCDF lacking any antioxidant activity was more active than CDF against T. gondii parasites. In conclusion, CDF and MeCDF are promising antiparasitic drug candidates due to their high activities against L. major and T. gondii parasites., (© 2021 The Authors. Chemistry & Biodiversity published by Wiley-VHCA AG, Zurich, Switzerland.)

Introduction: Leishmaniasis is a major public health problem that causes by parasite of the genus Leishmania. The pentavalent antimonial compounds that used for treatment are not safe or effective enough. The aim of the present study was preparation and evaluation of the efficacy of green synthesized silver nanoparticles against Leishmania major (L. major) in vitro., Methods: To synthesis silver (Ag) nanoparticles (NPs), ginger extract was added to the 0.2mM AgNO3 aqueous solution (1:20). Effects of different concentrations of Ag-NPs on the number of L. major promastigotes were investigated using counting assay. The MTT test was applied to determine the toxicity of Ag-NPs on promastigotes of L. major, as well as, macrophage cells. Then, to evaluate the anti-amastigotes effects of Ag-NPs, parasites within the macrophages were counted by light microscope. Furthermore, to determine the induced apoptosis and necrotic effects of Ag-NPs on promastigotes, flow cytometry method was employed using annexin staining., Results: The effect of Ag-NPs on promastigotes and amastigotes of L. major was effective and has a reverse relationship with its concentration. According to the results of anti-amastigote assay, the IC50 value of this nanoparticle was estimated 2.35 ppm after 72h. Also, Ag-NPs caused Programmed Cell Death (PCD) in promastigotes of L. major and showed 60.18% of apoptosis., Discussion: Based on the mentioned results, it can be concluded that Ag NPs has a beneficial effect on promastigote and amastigote forms of L. major in vitro. Hence, these nanoparticles could be applied as promising antileishmanial agents for treatment of Leishmania infections., Competing Interests: The authors have declared that no competing interests exist.

Background: Leishmaniasis is a parasitosis with a wide incidence in developing countries. The drugs which are indicated for the treatment of this infection usually are able to promote high toxicity., Purpose: A combination of limonene and carvacrol, monoterpenes present in plants with antiparasitic activity may constitute an alternative for the treatment of these diseases., Methods: In this study, the antileishmania activity against Leishmania major, cytotoxicity tests, assessment of synergism, parasite membrane damage tests as well as molecular docking and immunomodulatory activity of limonene-carvacrol (Lim-Car) combination were evaluated., Results: The Lim-Car combination (5:0; 1:1; 1:4; 2:3; 3:2; 4:1 and 0:5) showed potential antileishmania activity, with mean inhibitory concentration (IC 50 ) ranging from 5.8 to 19.0 μg.mL -1 . They demonstrated mean cytotoxic concentration (CC 50 ) ranging from 94.1 to 176.0 μg.mL -1 , and did not show significant hemolytic effect. In the investigation of synergistic interaction, the 4:1 Lim-Car combination showed better fractional inhibitory concentration (FIC) index as well as better activity on amastigotes and IS. The samples caused considerable damage to the parasite membrane this monoterpene activity seems to be more related to Trypanothione Reductase (TryR) enzyme interaction, demonstrated in the molecular docking assay. In addition, the 4:1 Lim-Car combination stimulated macrophage activation, and showed at was the best association, with reduction of infection and infectivity of parasitized macrophages., Conclusion: The 4:1 Lim-Car combination appears to be a promising candidate as a monotherapeutic antileishmania agent., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: In recent years, magnetic nanoparticles (NMP) as novel materials have been widely used for biomedical, diagnostic and therapeutic purposes like microbial infection therapy. The purpose of this study is to synthesize PO coated iron oxide magnetic nanoparticles (Fe3O4@PO NPs) and their anti-leishmanial effects in vitro and in vivo against cutaneous leishmaniasis., Methods: Fe3O4 magnetic nanoparticles were synthesized by the coprecipitation of Fe2 + and Fe3 + ions and used as a nanocarrier for the production of Fe3O4@PO NPs. The in vitro antileishmanial effects of PO-coated Fe3O4 NPs and Fe3O4 NPs (10-200 µg/mL) was determined against the intracellular amastigotes of Leishmania major (MRHO/IR/75/ER) and, then, examined on cutaneous leishmaniasis induced in male BALB/c mice by L. major. The rate of infectivity, production of nitric oxide (NO), and cytotoxic activates of Fe3O4 NPs and Fe3O4@PO NPs on J774-A1 macrophage cells were determined., Results: The size scattering of the Fe3O4 NPs and Fe3O4@PO NPs were in the range among 1-40 and 5-55 nm, respectively. The obtained IC 50 values were 62.3 ± 2.15 μg/mL, 31.3 ± 2.26 μg/mL, and 52.6 ± 2.15 μg/mL for the Fe3O4 NPs and Fe3O4@PO NPs, and MA, respectively. The results revealed that the mean number of parasites and the mean diameter of the lesions was considerably (p < 0.05) decreased in the infected mice treated with Fe3O4 NPs and Fe3O4@PO NPs. The Fe3O4 NPs and Fe3O4@PO NPs significantly (p < 0.05) prompted the production of NO as a dose-dependent manner. The promastigotes pre-incubated in Fe3O4 NPs and Fe3O4@PO NPs at the concentration of 5 µg/mL had the ability to infect only 41.7% and 28.3% of the macrophages cells. The selectivity index of greater than 10 for Fe3O4 NPs and Fe3O4@PO NPs showed its safety to the J774-A1 macrophage cells and specificity to the parasite., Conclusion: The results of this survey indicated the high potency of Fe3O4@PO NPs to inhibit the growth of amastigote forms of L. major as well as recovery and improvement CL induced by L. major in BALB/c mice without significant cytotoxicity. The results also indicated that, although the possible anti-leishmanial mechanisms of Fe3O4@PO NPs have not been clearly understood, however, the triggering of NO may be considered as one of the possible anti-leishmanial mechanisms of these nanoparticles. However, additional studies, in particular in clinical contexts, are mandatory., (Copyright © 2021 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

From the leaves of Ardisia quinquegona, two alkylated tetronic acid derivatives, named ardisiatetrons A and B (1, 2), and four triterpenoids (3-6) were isolated together with one known compound (7) by a combination of various kinds of chromatography. The structure of new methyl migrated triterpene (3) was confirmed by X-ray crystallographic analysis. Compounds 2, 3, and 7 showed moderate anti-Leishmania activity and cytotoxicity towards A549 cells.

Introduction. Leishmaniasis is a neglected tropical and subtropical disease caused by over 20 protozoan species. Hypothesis. Treatment of this complex disease with traditional synthetic drugs is a major challenge worldwide. Natural constituents are unique candidates for future therapeutic development. Aim. This study aimed to assess the in vivo anti-leishmanial effect of the Gossypium hirsutum extract, and its fractions compared to the standard drug (Glucantime, MA) in a murine model and explore the mechanism of action. Methodology. Footpads of BALB/c mice were infected with stationary phase promastigotes and treated topically and intraperitoneally with G. hirsutum extract, its fractions, or Glucantime, 4 weeks post-infection. The extract and fractions were prepared using the Soxhlet apparatus with chloroform followed by the column procedure. Results. The crude extract significantly decreased the footpad parasite load and lesion size compared to the untreated control group ( P <0.05), as revealed by dilution assay, quantitative real-time PCR, and histopathological analyses. The primary mode of action involved an immunomodulatory role towards the Th1 response in the up-regulation of IFN-γ and IL-12 and the suppression of IL-10 gene expression profiling against cutaneous leishmaniasis caused by Leishmania major . Conclusion. This finding suggests that the extract possesses multiple combinatory effects of diverse bioactive phytochemical compositions that exert its mechanisms of action through agonistic-synergistic interactions. The topical extract formulation could be a suitable and unique candidate for future investigation and pharmacological development. Further studies are crucial to evaluate the therapeutic potentials of the extract alone and in combination with conventional drugs using clinical settings.

The drugs used to treat cutaneous leishmaniasis (CL) cannot effectively penetrate lesions. Nanogold and nanosilver have been used for treating or enhancing drug delivery in CL. The present study used Commiphora molmol (myrrh) to synthesize silver nanoparticles (MSNPs). The MSNPs were characterized using transmission electron microscopy and energy-dispersive spectroscopy. In addition, antiparasitic effect of myrrh silver nanoparticles (MSNPs) was assessed on Leishmania major both in vitro and in vivo. Five concentrations of MSNPs (10, 50, 80, 100, and 150 μl/100 μL) were used to study their effect on L. major cultures in vitro, and MSNPs were also applied topically to subcutaneous lesions in mice in vivo. The results showed that the MSNPs were 49.09 nm in size. MSNPs, showed a marked and significant (p ≤ 0.05) growth inhibition of L. major promastigotes which was concentration dependent. Overall, the higher concentrations (100, 150 μl/100 μL had a significantly greater inhibitory effect for the MSNPs in comparison to the chemical nanoparticles (CNPs) and pentostam at the same concentrations. Lesions healed completely in 21 d after MSNP treatment in vivo, while pentostam, a commercial drug, and CNPs showed a moderate healing effect on the lesions. Thus, MSNPs were more effective than pentostam and CNPs both in the in vivo and in vitro studies. MSNPs can therefore be promising candidates for various nanomedicine applications., (Copyright © 2021 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Appropriate activation of macrophages is critical for the elimination of Leishmania parasites, which resides in this cell. Some species of Leishmania (L.) fails to stimulate macrophages and establish a chronic infection. To overcome this suppression and induce an innate immune response, the effect of PLGA-encapsulated soluble antigens of Leishmania (SLA) along with agonists of TLR1/2 (Pam3CSK4) and TLR7/8 (R848) nanoparticles (NPs) on activation of L. major-infected-macrophages were investigated and were compared with those of soluble formulations. SLA and R848 were encapsulated into the PLGA, while Pam3CSK4 adsorbed onto the surface of nanoparticles. The kinetics of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) and iNOS genes expression were investigated by qPCR over 72 h. The parasite load was also quantified by qPCR. The results indicated that engulfment of L. major promastigotes does not induce any pro-inflammatory cytokines expression by macrophages; however, the infected-cells are capable of responding to the TLRs agonists, and a lesser extent, to the SLA stimulation. Encapsulation resulted in increased strength of the IL-1β, IL-6, TNF-α, and increased and prolonged time of iNOS expression. Also, encapsulation showed the leishmanicidal activity by decreasing parasite load in treated NPs formulations. Among the different combinations of the components, the triple (SLA-R848-Pam3CSK4) forms promoted the highest activation of macrophages, followed by dual SLA-Pam3CSK4 and SLA-R848 NPs. In conclusion, the findings of this study indicate that the addition of SLA in combination with TLR1/2 and TLR7/8 agonists either in NPs or in soluble forms overcome the suppression of L. major-infected macrophages. Moreover, encapsulation increases the strength and duration of the cytokines and iNOS expression, in parallel with decreasing parasite load, suggesting a longer availability or delivery of the NPs into the macrophages. These findings highlight the advantages of particulate therapeutic vaccine formulations., (Copyright © 2021 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Leishmaniasis is a tropical parasitic disease that affects up to 12 million people worldwide. Current chemotherapies have limitations such as toxicity, high cost, and parasite resistance. This work aims to select an essential oil (EssOil) isolated from the Tunisian flora as a new antileishmanial candidate. Two plants were chosen for their antileishmanial potential: Citrus limon (Citrus) and Pistacia lentiscus (Pistacia). Each of these plants was harvested from two different sites (area 1 and area 2). Extracted EssOils were characterized using GC-MS. Their antiparasitic activity against axenic and intracellular Leishmania major amastigotes and their cytotoxicity were assessed. Citrus EssOil from area 1 displayed an interesting activity against L. major intramacrophage amastigotes with IC 50 value at 4.2 ± 1.3 μg/mL. Interestingly, this activity was close to that of miltefosine. Moderate activities against intracellular amastigote were observed for Pistacia EssOil from area 1 and Citrus EssOil from area 2. However, low cytotoxicity with high selectivity index was proved only for Citrus EssOil from area 1, revealing its safety for macrophages. This study also demonstrated for the first time the antileishmanial activity of EssOil extracted from Citrus limon leaves. The EssOil interesting activity could be related to the lipophilic properties of terpenes that were shown in literature to contribute to the disruption of parasite intracellular metabolic pathways.

Objective: Cutaneous leishmaniasis caused by Leishmania major ( L. major ) is an endemic disease in Iran. The current reference drugs, including Glucantime, possess high toxicity in addition to some side-effects. Therefore, there is a growing interest in exploring biomedical plants. The goal of the present study was to evaluate the anti-leishmanial activity and cytotoxicity of hydroalcoholic extracts from Prosopis farcta ( P. farcta ) over promastigote and amastigote forms., Methods: This study was performed at the Iran Birjand University of Medical Sciences, during the year 2019. In this study, the hydroalcoholic extracts of the stems, leaves (LE) and fruits (FE) of P. farcta were obtained. The anti-leishmanial activity was assessed against leptomonad promastigotes and intracellular amastigotes of L. major . The cytotoxicity of these extracts was determined in murine macrophages., Results: The FE and LE of P. farcta demonstrated a significant leishmanicidal effect against L. major promastigotes with an IC50 of 0.9 mg/mL and 1.1 mg/mL, respectively. The FE showed the most anti-leishmanial activity and presented with the highest index of selectivity (SI=14.6) as an anti-leishmanial product. Infected macrophages treated using the FE showed a reduction in parasite burden by 97.3%., Conclusion: The results of the present study demonstrated the leishmanicidal activity of P. farcta on both promastigotes and intracellular amastigotes. There is a need for performing comprehensive studies on relevant animal models and to access the effects of active components of P. farcta extract on the growth of L. major.

Leishmaniasis and toxoplasmosis are parasitic protozoal diseases that pose serious health concerns, especially for immunocompromised people. Leishmania major and Toxoplasma gondii are endemic in Saudi Arabia and are particularly common in the Qassim Region. The present work was conducted to evaluate the in vitro antileishmanial and antitoxoplasmal activity of methanolic extracts and phytochemical fractions from two plants, Euphorpia retusa and Pulicaria undulata, which are ethnobotanical agents used to treat parasitic infection. Whole E. retusa and P. undulata plants were extracted with methanol and fractionated using petroleum ether, chloroform, ethyl acetate, n-butanol, and water and then were tested in vitro against L. major promastigote and the amastigote stages of T. gondii; the cytotoxicity of the extracts was tested against Vero cell line. The methanolic extracts of E. retusa and P. undulata exhibited promising antitoxoplasmal activity against T. gondii with EC 50 values 5.6 and 12.7 μg mL -1 , respectively. The chloroform fraction of P. undulata was the most potent, exhibiting an EC 50 of 1.4 μg mL -1 and SI value of 12.1. It was also the most active fraction against both L. major promastigotes and amastigotes, exhibiting an EC 50 of 3.9 and 3.8 μg mL -1 and SI values 4.4 and 4.5, respectively. The chloroform fraction from P. undulata is a very good candidate for the isolation of active antitoxoplasmal and antileishmanial ingredients; therefore, further phytochemical analysis for active compound isolation is highly recommended.

Leishmaniasis constitutes a severe public health problem, with an estimated prevalence of 12 million cases. This potentially fatal disease has a worldwide distribution and in 2012, the fatal Visceral Leishmaniasis (VL) was declared as new emerging disease in Europe, mainly due to global warming, with expected important public health impact. The available treatments are toxic, costly or lead to parasite resistance, thus there is an urgent need for new drugs with new mechanism of action. Previously, we reported the discovery of CTN1122, a potent imidazo[1,2-a]pyrazine-based antileishmanial hit compound targeting L-CK1.2 at low micromolar ranges. Here, we described structurally related, safe and selective compounds endowed with antiparasitic properties, better than miltefosine, the reference therapy by oral route. L-CK1.2 homology model gave the first structural explanations of the role of 4-pyridyl (CTN1122) and 2-aminopyrimidin-4-yl (compound 21) moieties, at the position 3 of the central core, in the low micromolar to nanomolar L-CK1.2 inhibition, whereas N-methylpyrazole derivative 11 remained inactive against the parasite kinase., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

Background: Cutaneous leishmaniasis caused by Leishmania species ( L. spp ) is one of the most important parasitic diseases in humans. To gain information on the metabolite variations and biochemical pathways between L. spp , we used the comparative metabolome of metacyclic promastigotes in the Iranian isolates of L. major and L. tropica by proton nuclear magnetic resonance ( 1 H-NMR)., Methods: L. tropica and L. major were collected from three areas of Iran, namely Gonbad, Mashhad, and Bam, between 2017 and 2018, and were cultured. The metacyclic promastigote of each species was separated, and cell metabolites were extracted. 1 H-NMR spectroscopy was applied, and the data were processed using ProMatab in MATLAB (version 7.8.0.347). Multivariate statistical analyses, including the principal component analysis and the orthogonal projections to latent structures discriminant analysis, were performed to identify the discriminative metabolites between the two L. spp . Metabolites with variable influences in projection values of more than one and a P value of less than 0.05 were marked as significant differences., Results: A set of metabolites were detected, and 24 significantly differentially expressed metabolites were found between the metacyclic forms of L. major and L. tropica isolates. The top differential metabolites were methionine, aspartate, betaine, and acetylcarnitine, which were increased more in L. tropica than L. major (P<0.005), whereas asparagine, 3-hydroxybutyrate, L-proline, and kynurenine were increased significantly in L. major (P<0.01). The significantly altered metabolites were involved in eight metabolic pathways., Conclusion: Metabolomics, as an invaluable technique, yielded significant metabolites, and their biochemical pathways related to the metacyclic promastigotes of L. major and L. tropica . The findings offer greater insights into parasite biology and how pathogens adapt to their hosts., (Copyright: © Iranian Journal of Medical Sciences.)