Leishmanicidal Potential Research Articles

An Overview of Leishmania In Vitro Cultivation and Implications for Antileishmanial Screenings against Promastigotes

The quest for new drug candidates targeting neglected parasitic diseases has become increasingly urgent over the past decades. Advancements in formulating and optimizing drug delivery systems begin with basic research, including direct assays to evaluate the activity of molecules against parasitic stages maintained in laboratories; i.e., promastigotes. In the context of leishmaniasis, an endemic disease worldwide, the cultivation of Leishmania parasites can vary significantly across different laboratories. Factors such as culture media composition, pH, supplementation, and temperature can lead to varied drug responses in in vitro activity assays. This study aims to compile the parameters used in Leishmania spp. promastigotes cultivation protocols described in scientific articles published in indexed journals over the past ten years. The data reveal a lack of uniformity among Leishmania culture protocols, suggesting a potential bottleneck in comparing the leishmanicidal potential of in vitro drug candidates reported by different research groups. This condition is crucial to consider, because viability/inhibition assays should begin with fully-grown, healthy promastigote cultures capable of homogeneous division, thereby producing more reproducible results.

Antiparasitary potential of Sarcomphalus joazeiro (Mart.) Hauenschild (Rhamnaceae)

Leishmaniasis and American trypanosomiasis are part of a set of diseases characterized by the World Health Organization as neglected diseases caused by infectious and parasitic agents in populations in situations of poverty and poor sanitation. Pharmaceutical industries neglect such diseases, which have limited treatments, mainly due to few drug options and significant toxicity. Therefore, it is essential to search for new substances that have the potential to replace these medications. In this context, this study aimed to evaluate the leishmanicidal and trypanocidal activity of the ethanolic extract of the leaves and bark of Sarcomphalus joazeiro (Mart.) Hauenschild. These extracts were prepared by maceration with cold extraction. When carrying out the susceptibility tests, the extracts were tested in four different concentrations against the epimastigote forms of the CL-B5 parasite strains of Trypanosoma cruzi and promastigote forms of Leishmania braziliensis and Leishmania infantum, both tests were carried out "in vitro" in plates 96-well microdilution system, with nifurtimox and metronidazole as reference medicine. The cytotoxicity assay was performed with mammalian fibroblast lines from the NCTC 929 clone. The results indicate that the ethanolic extract of the bark of the stem of S. joazeiro (EBSJ) presented a more significant antiparasitic effect when compared to the ethanolic extract of the leaves of Sarcomphalus joazeiro (ELSJ) particularly against L. braziliensis and L. infantum. Regarding cytotoxicity, EBSJ and ELSJ presented moderate and low degrees, respectively. Based on the data obtained, further investigations into the properties of the bark extract are necessary, mainly due to its leishmanicidal potential.

Dioclea violacea lectin has potent in vitro leishmanicidal activity against Leishmania infantum via carbohydrate recognition domain

Despite promising advancements in leishmaniasis treatment, existing therapies often face limitations and significant side effects, stimulating the search for novel therapeutic alternatives. In this context, lectins, such as DVL extracted from Dioclea violacea seeds, have emerged as potential candidates due to their diverse biological activities. This study represents the first investigation of the leishmanicidal potential of DVL in vitro against Leishmania infantum. Our results demonstrate that DVL exhibits a leishmanicidal effect (IC50/24 h = 49.37 μg/mL or 2 μM), binding to glycans on L. infantum. Fluorescence assays revealed that DVL can induce the production of reactive oxygen species (ROS) and cause damage to the parasite's membrane. DVL demonstrated a modulating effect when combined with amphotericin B and glucantime, enhancing the activity of these drugs by 40 % and 80 %, respectively. It also showed no cytotoxicity in Raw 264.7 cells and was able to override the toxic effect of amphotericin B on cells and reduce the survival rate of macrophages infected with amastigote forms, as well as their percentage of infection by 31 %. Therefore, DVL shows promise as a treatment for visceral leishmaniasis caused by L. infantum. Our findings provide valuable insights for future therapeutic development targeting leishmania glycans.

Computational and experimental approaches manifest the leishmanicidal potential of α-mangostin resourced from Garcinia cowa

Owing to the persistent number of parasitic deaths, Visceral leishmaniasis continues to haunt several economically weaker sections of India. The disease causes over 30,000 deaths and threatens millions annually on a global scale. The standard pentavalent antimonials, on the other hand, are associated with health adversities and disease relapse. The current study is focused on the search for the most potential natural bioactive phytocompound from the bark extract of the Northeastern Indian plant, Garcinia cowa, that shows potent anti-leishmanial properties. The High Resonance Liquid Chromatography followed by Mass Spectrometry (HR-LCMS) study followed by an in silico molecular docking using computational tools revealed that α-mangostin might potentially possess antiparasitic activity. To validate the anti-leishmanial efficacy of the compound, a cell viability assay was performed, which demonstrated the parasite-specific inhibitory activity of α-mangostin; with IC50 values ranging from 4.95 - 7.37 µM against the different forms of Leishmania donovani parasite. The flow cytometric analysis of the phytocompound treated parasites indicated an oxidative and nitrosative stress-mediated apoptotic cell death in the parasites, by the suggestive surge in nuclear fragmentation and mitochondrial dysfunction. Simultaneously, a cytokine profiling study suggested approximate two-to-three-fold upregulated levels of pro-inflammatory cytokines post-compound treatment, which is predicted to actively contribute to parasite-killing. α-mangostin was also found to reduce the chances of parasite survival by inhibiting arginase enzyme activity, which in favorable conditions facilitates its sustenance. This study thereby substantiates that α-mangostin significantly possesses anti-leishmanial potentiality that can be developed into a cure for this infectious disease.

Promising Antileishmanial Activity of Micromeria nervosa Essential Oil: In Vitro and In Silico Studies.

The present study aimed to evaluate the leishmanicidal potential of the essential oil (EO) of Micromeria (M.) nervosa and to investigate its molecular mechanism of action by qPCR. Furthermore, in silicointeraction study of the major M. nervosa EO compounds with the enzyme cytochrome P450 sterol 14α-demethylase (CYP51) was also performed. M. nervosa EO was analyzed by gas chromatography-mass spectrometry (GC-MS). Results showed that α-pinene (26.44%), t-cadinol (26.27%), caryophyllene Oxide (7.73 ± 1.04%), and α-Cadinene (3.79 ± 0.12%) are the major compounds of M. nervosa EO. However, limited antioxidant activity was observed, as this EO was ineffective in neutralizing DPPH free radicals and in inhibiting β-carotene bleaching. Interestingly, it displayed effective leishmanicidal potential against promastigote (IC50 of 6.79 and 5.25 μg/mL) and amastigote (IC50 of 8.04 and 7.32 μg/mL) forms of leishmania (L.) infantum and L. major, respectively. Molecular mechanism investigation showed that M. nervosa EO displayed potent inhibition on the thiol regulatory pathway. Furthermore, a docking study of the main components of the EO with cytochrome P450 sterol 14α-demethylase (CYP51) enzyme revealed that t-cadinol exhibited the best binding energy values (-7.5 kcal/mol), followed by α-cadinene (-7.3 kcal/mol) and caryophyllene oxide (-7 kcal/mol). These values were notably higher than that of the conventional drug fluconazole showing weaker binding energy (-6.9 kcal/mol). These results suggest that M. nervosa EO could serve as a potent and promising candidate for the development of alternative antileishmanial agent in the treatment of leishmaniasis.

An Evaluation of the Antibacterial, Antileishmanial, and Cytotoxic Potential of the Secondary Metabolites of Streptomyces sp. ARH (A3).

This study aimed to evaluate the antibacterial, leishmanicidal, and cytotoxic potential of metabolites produced by bacteria isolated from rhizosphere soil samples. The bacterium was identified by genome sequencing as Streptomyces kronopolitis. A preliminary screening was carried out for the antimicrobial activity of S. kronopolitis, demonstrating activity against Staphylococcus aureus ATCC 6538, Corynebacterium diphtheriae ATCC 27010, C. diphtheriae ATCC 27012, and Mycobacterium abscessus, with inhibition halos of sizes 25, 36, 29, and 33 mm, respectively. To obtain secondary metabolites, the bacteria were subjected to submerged fermentation, and the metabolites were extracted using the liquid-liquid method with ethyl acetate. There was a similar MIC for M. abscessus and the two strains of C. diphtherium, reaching a concentration of 12.5 µg/mL, while that of S. aureus was 0.048 µg/mL. Assays for leishmanicidal activity and cytotoxicity against HEp-2 cells and red blood cells were performed. The metabolite showed an IC50 of 9.0 ± 0.9 µg/mL and CC50 of 221.2 ± 7.0 µg/mL. This metabolite does not have hemolytic activity and is more selective for parasites than for mammalian cells, with a selectivity index of 24.6. Thus, the studied metabolite may be a strong candidate for the development of less toxic drugs to treat diseases caused by pathogens.

Curcumin-loaded nanostructured systems for treatment of leishmaniasis: a review.

Leishmaniasis is a neglected tropical disease that has affected more than 350 million people worldwide and can manifest itself in three different forms: cutaneous, mucocutaneous, or visceral. Furthermore, the current treatment options have drawbacks which compromise efficacy and patient compliance. To face this global health concern, new alternatives for the treatment of leishmaniasis have been explored. Curcumin, a polyphenol obtained from the rhizome of turmeric, exhibits leishmanicidal activity against different species of Leishmania spp. Although its mechanism of action has not yet been fully elucidated, its leishmanicidal potential may be associated with its antioxidant and anti-inflammatory properties. However, it has limitations that compromise its clinical use. Conversely, nanotechnology has been used as a tool for solving biopharmaceutical challenges associated with drugs, such as curcumin. From a drug delivery standpoint, nanocarriers (1-1000 nm) can improve stability, increase solubility, promote intracellular delivery, and increase biological activity. Thus, this review offers a deep look into curcumin-loaded nanocarriers intended for the treatment of leishmaniasis.

Insight into the inhibitory potential of metal complexes supported by (E)-2-morpholino-N-(thiophen-2-ylmethylene)ethanamine: synthesis, structural properties, biological evaluation and docking studies.

A thiophene-derived Schiff base ligand (E)-2-morpholino-N-(thiophen-2-ylmethylene)ethanamine was used for the synthesis of M(II) complexes, [TEM(M)X2] (M = Co, Cu, Zn; X = Cl; M = Cd, X = Br). Structural characterization of the synthesized complexes revealed distorted tetrahedral geometry around the M(II) center. In vitro investigation of the synthesized ligand and its M(II) complexes showed considerable anti-urease and leishmanicidal potential. The synthesized complexes also exhibited a significant inhibitory effect on urease, with IC50 values in the range of 3.50-8.05 μM. In addition, the docking results were consistent with the experimental results. A preliminary study of human colorectal cancer (HCT), hepatic cancer (HepG2), and breast cancer (MCF-7) cell lines showed marked anticancer activities of these complexes.

Medicinal plants with antileishmanial activity on parasites responsible for new-world cutaneous leishmaniasis. A systematic review 2018-2022

Context: Cutaneous leishmaniasis is a disease of public health importance; treatment is based on the use of pentavalent antimonials with high toxicity and low efficacy; therefore, it´s necessary to search for therapeutic alternatives derived from natural products, based on the study of medicinal plants as a source of molecules with highly effective leishmanicidal potential. Aims: To carry out a systematic review between 2018 and 2022 on medicinal plants with potential leishmanicidal activity on parasite strains from the New World causing cutaneous leishmaniasis. Methods: The review study was conducted in four phases following the PRISMA methodology. First, research questions and objectives were formulated to establish the topic areas and construct the search algorithm. Second, a search was performed across different databases, including ScienceDirect, Scopus, PubMed, Web of Science, EBSCO, Taylor and Francis, and Scielo. Third, articles were chosen based on specific inclusion and exclusion criteria. Finally, the relevant information for the review was systematically organized. Results: The search yielded 163 articles, and 12 of them were selected as the basis for the construction of the review. Ethanolic and aqueous extracts stand out, as well as biocompounds such as terpenes and flavonoids. Antioxidant activity on reactive oxygen species was the most frequently cited. Conclusions: Promising terpene and flavonoid molecules with high antileishmanial activity (IC50 <2 μM or <10 μg/mL and SI >1) were identified in this study; these findings provide a scientific basis for the traditional use that communities have given to plants as a therapeutic source to treat cutaneous leishmaniasis in the New World.

Biostimulated-sesame sprout extracts as potential agents against Leishmania mexicana.

Leishmania mexicana is one of the causal agents of cutaneous leishmaniasis. Current antileishmanial chemotherapeutics have demonstrated adverse side effects; thus, alternative treatments are needed. In this study, we performed in silico and in vitro analyses of the leishmanicidal potential of the most abundant phenolic compounds identified in black sesame sprouts biostimulated with Bacillus clausii. The molecular docking analysis showed strong interactions (binding free energies between -6.5 and -9.5 kcal/mol) of sesaminol 2-O-triglucoside, pinoresinol dihexoside, isoverbascoside, and apigenin with the arginase, leishmanolysin, cysteine peptidase B, and pyruvate kinase leishmanial enzymes. Furthermore, almost all phenolic compounds interacted with the active site residues of L. mexicana enzymes. In vitro, the B. clausii-biostimulated sprout phenolic extracts and apigenin inhibited the growth of promastigotes with IC50 values of 0.08 mg gallic acid equivalent/mL and 6.42 μM (0.0017 mg/mL), respectively. Additionally, in the macrophage infection model, cells treated with B. clausii-biostimulated sprout phenolic extracts and infected with L. mexicana exhibited significantly (P<0.05) reduced nitric oxide production and decreased parasite burden. Altogether, our study provides important data related to high efficacy and less toxic natural antileishmanial candidates against promastigotes of L. mexicana.

Exploring the leishmanicidal potential of terpenoids: a comprehensive review on mechanisms of cell death.

Leishmaniasis is a neglected tropical disease with a wide spectrum of clinical manifestations, ranging from visceral to cutaneous, with millions of new cases and thousands of deaths reported each year. The species of Leishmania and the immune response of the host determine the severity of the disease. Leishmaniasis remains challenging to diagnose and treat, and there is no vaccine available. Several studies have been conducted on the use of herbal medicines for the treatment of leishmaniasis. Natural products can provide an inexhaustible source of chemical diversity with therapeutic potential. Terpenes are a class of natural products derived from a single isoprene unit, a five-carbon compound that forms the basic structure of isoprenoids. This review focuses on the most important and recent advances in the treatment of parasites of the genus Leishmania with different subclasses of terpenes. Several mechanisms have been proposed in the literature, including increased oxidative stress, immunomodulatory role, and induction of different types of parasite cell death. However, this information needs to be brought together to provide an overview of how these compounds can be used as therapeutic tools for drug development and as a successful adjuvant strategy against Leishmania sp.

Anti-Candida and Anti-Leishmanial Activities of Encapsulated Cinnamomum verum Essential Oil in Chitosan Nanoparticles.

Nanoencapsulation is widely considered as a highly effective strategy to enhance essential oils' (EO) stability by protecting them from oxidative deterioration and evaporation. The present study aims to optimize and characterize an efficient technique for encapsulating Cinnamomum (C.) verum essential oil into chitosan nanoparticles using response surface methodology (RSM). Moreover, the optimized C. verum EO nanoparticle was investigated for its antibacterial (against Gram-positive and Gram-negative bacteria), antifungal (against Candida albicans), and antiparasitic activity (against Leishmania parasites). Five parameters were investigated using a Plackett-Burman and Box-Behnken statistical design: the chitosan molecular weight, TPP concentration, C. verum EO/chitosan ratio, mixing method, and the duration of the reaction. Encapsulation efficiency and anti-candida activity were considered as responses. The antibacterial, anticandidal, and anti-leishmanial activities were also assessed using a standard micro-broth dilution assay and the cytotoxicity assay was assessed against the macrophage cell line RAW 264.7. The optimized nanoparticles were characterized using Fourier transform infrared spectroscopy, Zeta potential, and scanning electron microscopy. The study results indicated that under optimal conditions, the nanoencapsulation of C. verum EO into chitosan nanoparticles resulted in an encapsulation efficiency of 92.58%, with a regular distribution, a nanoparticle size of 480 ± 14.55 nm, and a favorable Zeta potential of 35.64 ± 1.37 mV. The optimized C. verum EO/chitosan nanoparticles showed strong antifungal activity against C. albicans pathogens (CMI = 125 µg mL-1), notable antibacterial activity against both Gram-positive and Gram-negative bacteria (ranging from 125 to 250 µg mL-1), high leishmanicidal potential against the promastigotes form of L. tropica and L. major (IC50 = 10.47 and 15.09 µg mL-1, respectively), and a four-fold cytotoxicity reduction compared to non-encapsulated essential oil. These results suggest that C. verum EO-loaded chitosan nanoparticles could be a promising delivery system for the treatment of cutaneous Candida albicans infections.

Pyridine‐derived Schiff base copper (II), zinc (II), and cadmium (II) complexes: Synthesis, structural properties, biological evaluation, and docking studies

Herein, Cu (II), Zn (II), and Cd (II) complexes, [DEP(M)X2], encompassing the pyridine‐derived Schiff‐base ligand DEP, where DEP is (E)‐N,N‐diethyl‐2‐([pyridine‐2‐ylmethylene]amino)ethane‐1‐amine, are synthesized. X‐ray diffraction studies reveal distorted square pyramidal geometries for the Cd (II) and Cu (II) complexes, whereas the geometry of [DEP (Zn)Cl2] can best be described as trigonal bipyramidal. The antibacterial potential of DEP and its [DEP(M)X2] complexes were evaluated against four bacterial strains: Salmonella typhi, Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa; five fungal strains: Candida glabrata, Candida albicans, Microsporum canis, Fusarium solani, and Aspergillus flavus; and Leishmania major protozoan. Complexes exhibited superior bactericidal, fungicidal, and leishmanicidal inhibition potential against all tested microbes compared with the free ligand. The preliminary cytotoxic activity of [DEP(M)X2] complexes on breast and colon carcinoma cells, that is, MCF‐7cell line and HCT‐116 cell line, respectively, revealed that studied complexes showed high cytotoxicity compared with ligand (DEP). Among the studied complexes, [DEP (Cd)Br2] exhibited an excellent inhibitory profile, as confirmed by the docking study. The molecular docking studies showed a good correlation between the biological activities of synthesized metal complexes and docking studies. We have confidence in the contribution of these complexes toward the design of new metal‐derived candidates that can treat infectious diseases.

Biochemical characterization and assessment of leishmanicidal effects of a new L-amino acid oxidase from Crotalus durissus collilineatus snake venom (CollinLA AO-I)

This study reports the isolation of CollinLAAO-I, a new L-amino acid oxidase from Crotalus durissus collilineatus snake venom, its biochemical characterization and leishmanicidal potential in Leishmania spp. CollinLAAO-I (63.1 kDa) was successfully isolated with high purity using two chromatographic steps and represents 2.5% of total venom proteins. CollinLAAO-I displayed high enzymatic activity (4262.83 U/mg/min), significantly reducing after 28 days. The enzymatic activity of CollinLAAO-I revealed higher affinity for hydrophobic amino acids such as L-leucine, high enzymatic activity in a wide pH range (6.0–10.0), at temperatures from 0 to 25 °C, and showed complete inhibition in the presence of Na+ and K+. Cytotoxicity assays revealed IC50 of 18.49 and 11.66 μg/mL for Leishmania (L.) amazonensis and Leishmania (L.) infantum, respectively, and the cytotoxicity was completely suppressed by catalase. CollinLAAO-I significantly increased the intracellular concentration of reactive oxygen species (ROS) and reduced the mitochondrial potential of both Leishmania species. Furthermore, CollinLAAO-I decreased the parasite capacity to infect macrophages by around 70%, indicating that even subtoxic concentrations of CollinLAAO-I can interfere with Leishmania vital processes. Thus, the results obtained for CollinLAAO-I provide important support for developing therapeutic strategies against leishmaniasis.

Understanding the characteristics of phytofabricated silver nanoparticles and their leishmanicidal potential against Indian strain of Leishmania donovani

Understanding the characteristics of phytofabricated silver nanoparticles and their leishmanicidal potential against Indian strain of Leishmania donovani

Essential Oils of Rosmarinus officinalis and Eucalyptus globulus Cultivated in the Mountainous Region of the State of Rio de Janeiro (Brazil): Chemical Profile and Antileishmanial Activity

Pharmacognosy Research,2023,15,2,297-306.DOI:10.5530/pres.15.2.032Published:February 2023Type:Original Article Authors:Rogéria Cristina Zauli, Tarcísio Martins Santos, Alberto Wisniewski Jr, Patrícia Xander, and Aislan Cristina Rheder Fagundes Pascoal Author(s) affiliations:Rogéria Cristina Zauli1, 2, 3, Tarcísio Martins Santos4, Alberto Wisniewski Jr4, Patrícia Xander1, 3, Aislan Cristina Rheder Fagundes Pascoal5,* 1Department of Pharmaceutical Sciences, Institute of Environmental, Chemical and Pharmaceutical Sciences, Laboratory of Cellular Immunology and Biochemistry of Fungi and Protozoa, Federal University of São Paulo, Diadema, São Paulo, BRAZIL. 2Technical Support Center for Teaching, Research and Extension (NATEPE), Federal University of São Paulo, Campus Diadema, Diadema, São Paulo, BRAZIL. 3Biology-Chemistry Graduate Program, Federal University of São Paulo, Campus Diadema, Diadema, São Paulo, BRAZIL. 4Department of Chemistry, Federal University of Sergipe, Av. Marechal Rondon, São Cristóvão, SE, BRAZIL 5Department of Basic Sciences, Multi-user Biomedical Research Laboratory, Fluminense Federal University (ISNF-UFF), Nova Friburgo, Rio de Janeiro, BRAZIL. Abstract:The present study aimed to characterize the chemical profile of essential oils of Rosmarinus officinalis (EORo) and Eucalyptus globulus (EOEg) cultivated in the mountainous region of the state of Rio de Janeiro, Brazil, and to verify the leishmanicidal potential, as well as to determine the cytotoxicity in vitro in mammalian cells. EORo had α-Pinene (37.99%), Cineol (21.48%), D-Verbenone (5.78%) and Limonene (3.28%) as major constituents. The EOEg had as major components Cineol (75.52%), Limonene (8.82%) and o-Cymeno (7.81%). The EOEg had a lower IC50 value of 14.03 ± 2.08 μg/mL, while EORo had an IC50 value of 31.12 ± 4.6 μg/mL, both during the 24-hr exposure period. In the 48-hr period, the IC50 value was almost twice as high with rosemary oil, while in eucalyptus oil there was no significant difference when exposed in this period. The selectivity of EOs was demonstrated in murine cells, showing almost 30 times less toxic to the cell than to the parasite. It can be concluded that this is a pioneering study on the potential of these essential oils against the leishmania parasite. Furthermore, the low toxicity effect on the host cell encourages future studies and in vivo applications. Keywords:cytotoxicity, E. globulus, Essential oil, Leishmanicidal, R. officinalisView:PDF (359.76 KB)

Evaluation of the In Vitro Antiparasitic Effect of the Essential Oil of Cymbopogon winterianus and Its Chemical Composition Analysis.

Cymbopogon winterianus, known as “citronella grass”, is an important aromatic and medicinal tropical herbaceous plant. The essential oil of C. winterianus (EOCw) is popularly used to play an important role in improving human health due to its potential as a bioactive component. The present study aimed to identify the components of the essential oil of C. winterianus and verify its leishmanicidal and trypanocidal potential, as well as the cytotoxicity in mammalian cells, in vitro. The EOCw had geraniol (42.13%), citronellal (17.31%), and citronellol (16.91%) as major constituents. The essential oil only exhibited significant cytotoxicity in mammalian fibroblasts at concentrations greater than 250 μg/mL, while regarding antipromastigote and antiepimastigote activities, they presented values considered clinically relevant, since both had LC50 < 62.5 μg/mL. It can be concluded that this is a pioneer study on the potential of the essential oil of C. winterianus and its use against the parasites T. cruzi and L. brasiliensis, and its importance is also based on this fact. Additionally, according to the results, C. winterianus was effective in presenting values of clinical relevance and low toxicity and, therefore, an indicator of popular use.

In Vitro Cytotoxic and Leishmanicidal Activity of Isolated and Semisynthetic ent-Pimaranes from Aldama arenaria.

Two pimaranes ent-pimara-8(14),15-dien-19-oic acid (1: ) and ent-8(14),15-pimaradien-3β-ol (2: ), isolated from Aldama arenaria, and six semi-synthetic derivatives methyl ester of the ent-pimara-8(14),15-dien-19-oic acid (3: ), ent-pimara-8(14),15-dien-19-ol (4: ), acetate of ent-pimara-8(14),15-dien-19-ol (5: ), ent-pimara-8(14),15-dien-19-ol succinic acid (6: ), acetate of ent-8(14),15-pimaradien-3β-ol (7: ), ent-8(14),15-pimaradien-3β-ol succinic acid (8: ) were evaluated in vitro for their cytotoxic activities to childhood leukemia cell lines and leishmanicidal activity against the parasite Leishmania amazonensis. Among these compounds, 1: to 6: presented moderate cytotoxic activity, with compound 4: being the most active (GI50 of 2.6 µM for the HL60 line) and the derivatives 7: and 8: being inactive. Against the parasite Leishmania amazonensis, the most promising derivative was the acetate of ent-pimara-8(14),15-dien-19-ol (5: ), with EC50 of 20.1 µM, selectivity index of 14.5, and significant reduction in the parasite load. Pimarane analogues 1: , ent-pimara-8(14),15-dien-19-oic acid, and 2: , ent-8(14),15-pimaradien-3β-ol, presented different activities, corroborating the application of such molecules as prototypes for the design of other derivatives that have greater cytotoxic or leishmanicidal potential.

Synergistic Anti-Leishmanial Activities of Morphine and Imiquimod on Leishmania infantum (MCAN/ES/98/LIM-877).

Background:This study was performed to evaluate in vitro and in vivo Leishmanicidal potential of morphine (Mph), imiquimod (IQ), and their combination.Methods:Leishmania infantum promastigote and amastigote assays were performed at the presence of 0.015–150μM Mph, 0.04–416μM IQ, and their combination. The inhibition effects of these drugs on promastigotes were evaluated after 24, 48, and 72h. The cytotoxic effects of the drugs were evaluated by MTT as well as flow cytometry after 72h. We explored the therapeutic effects of Mph and IQ in BALB/c mice at the end of the treatment using parasite load determination and cytokine assay. One group of mice received Mph for three weeks before infection.Results:The results of promastigote and amastigote assays showed the cytotoxic effects of the drugs at low concentrations. The cytotoxic effects were higher on promastigotes than amastigotes (p< 0.05). There was a negative correlation between drug concentration and amastigote/promastigote viability. Imiquimod alone or combined with Mph showed remarkable cytotoxic effects at all concentrations (p< 0.05). Flow cytometry results revealed apoptosis in the parasite following exposure to the drug combinations. Accordingly, the reduction of parasite loads in the spleen and liver was observed (p< 0.05) with simultaneous increases in IFN-γ and IL-4. We believe that the in vivo leishmanicidal effect was mediated by Mph through IL-4 and by IQ through both IL-4 and IFN-γ.Conclusion:Results pointed out the promising effects of Mph and IQ at low concentrations, especially when combined.

Structural characterization of a galectin isolated from the marine sponge Chondrilla caribensis with leishmanicidal potential

BackgroundSolving primary structure of lectins leads to an understanding of the physiological roles within an organism and its biotechnological potential. Only eight sponge lectins have had their primary structure fully determined. MethodsThe primary structure of CCL, Chondrilla caribensis lectin, was determined by tandem mass spectrometry. The three-dimensional structure was predicted and the protein-carbohydrate interaction analysed by molecular docking. Furthermore, the anti-leishmanial activity was observed by assays with Leishmania infantum. ResultsThe amino acid sequence consists of 142 amino acids with a calculated molecular mass of 15,443 Da. The lectin has a galectin-like domain architecture. As observed in other sponge galectins, the signature sequence of a highly conserved domain was also identified in CCL with some modifications. CCL exhibits a typical galectin structure consisting of a β-sandwich. Molecular docking showed that the amino acids interacting with CCL ligands at the monosaccharide binding site are mostly the same as those conserved in this family of lectins. Through its interaction with L. infantum glycans, CCL was able to inhibit the development of this parasite. CCL also induced apoptosis after eliciting ROS production and altering the membrane integrity of Leishmania infantum promastigote. ConclusionsCCL joins the restricted group of sponge lectins with determined primary structure and very high biotechnological potential owing to its promising results against pathogens that cause Leishmaniasis. General significanceAs the determination of primary structure is important for biological studies, now CCL can become a sponge galectin with an exciting future in the field of human health.