Unsaturated lipids modulating the interaction of the antileishmanial isolinderanolide E with models of cellular membranes.

The present work evaluated the antiprotozoal activity of isolinderanolide E, isolated from the Brazilian plant Nectandra oppositifolia, against promastigote forms of Leishmania (Leishmania) amazonensis. The compound exhibited an EC50 value of 20.3 µM, similar to the positive control miltefosine (IC50 of 19.4 µM), and reduced toxicity to macrophages (CC50 > 200 µM). Based on these results, Langmuir monolayers of two unsaturated lipids: 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), were employed as a model of mammalian and parasite membranes, respectively, to study the interaction of isolinderanolide E at a molecular level. The films were characterized with tensiometry (surface pressure-area isotherms and surface pressure-time curves), infrared spectroscopy, and Brewster angle microscopy (BAM). This compound changed the profile of the isotherms leading to fluid DOPC and DOPE monolayers, which were not able to attain rigid states even with compression. Infrared spectroscopy showed that the bioactive compound decreases the trans/gauche ratio conformers related to the molecular conformational disorder. BAM showed the formation of specific aggregates upon drug incorporation. In conclusion, isolinderanolide E changes the thermodynamic, mechanical, structural, and morphological characteristics of the monolayer of these unsaturated lipids, which may be essential to understand the action at the molecular level bioactives in biointerfaces.

Histological and neuronal changes in the duodenum of hamsters infected with Leishmania (Leishmania) infantum.

Visceral leishmaniasis is a neglected tropical disease caused by parasites belonging to the Leishmania genus that infect macrophages in different tissues such as the spleen, liver, lymph nodes, bone marrow, and intestine. Therefore, this study aimed to investigate the integrity of the intestinal tract and the nitrergic (NADPH-dp) and metabolically active (NADH-dp) myenteric neurons of the duodenum of golden hamsters infected with L. (L.) infantum. Therefore, thirty golden hamsters were divided into six groups (n = 5); three of them were infected with 2 × 107 promastigote forms of L. (L.) infantum by intraperitoneal route (Infected Group - IG) and three were inoculated with saline solution (control group - CG). After 30, 60 and 90 days post-infection (DPI) infected animals were euthanized and the liver, spleen and duodenum were collected to analyze tissue parasitism. The duodenum was processed using usual histological techniques to analyze the main changes that occurred during infection and histochemical techniques to phenotype myenteric neurons. Amastigote forms were observed in the spleen, liver, and duodenum during all experimental periods, and tissue parasitism in these organs increased significantly over time. At 30 DPI, reduction in muscle tunic, increase in the total intestinal wall and the number of goblet cells PAS+ was observed. At 60 DPI, an increase in intestinal crypts and intraepithelial lymphocytes was observed, and a reduction in intestinal villi was observed at 90 DPI, along with an increase in crypt size. Regarding neurons, an increase in the density of the NADPH-dp population was observed at 30 DPI, but at 60 and 90 DPI a significant reduction of this population was observed. In general, infection progression was observed to cause significant morphofunctional changes in the duodenum of infected hamsters.

Canine neutrophils cooperate with macrophages in the early stages of Leishmania infantum in vitro infection.

Leishmania infantum is the aetiological agent of human visceral leishmaniasis and canine leishmaniasis, both systemic and potentially fatal diseases. Polymorphonuclear neutrophils (PMN) are the first cells to phagocyte this parasite at the inoculation site, but macrophages (MØ) are the definitive host cells, ensuring parasite replication. The interaction between dog MØ, PMN and L infantum promastigotes was in vitro investigated. It was observed that promastigotes establish contact with blood monocyte-derived MØ mainly by the tip of the flagellum. These cells, that efficiently bind and internalize parasites, underwent major morphological changes, produced nitric oxide (NO) and released histone H1 in order to inactivate the parasite. Transfer of intracellular parasites from PMN to MØ was confirmed by flow cytometry, using L infantum expressing a green fluorescent protein. The interaction of MØ with L infantum-infected PMN lead to NO production and release of extracellular traps, which may contribute to parasite containment and inactivation. This study highlights for the first time the diversity of cellular and molecular events triggered by the interaction between canine PMN and MØ, which can promote a reduction of parasite burden in the early phase of L infantum infection.

Antileishmanial activity and ultrastructural changes of sesquiterpene lactones isolated from Calea pinnatifida (Asteraceae).

Bioactivity-guided fractionation of antileishmanial active CH2Cl2 phase of MeOH extract from leaves of Calea pinnatifida led to isolation of two sesquiterpene lactones calein C (1) and calealactone C (2), which structures were stablished on the basis of spectroscopic analysis. Compounds 1 and 2 displayed potent activity against Leishmania amazonensis promastigotes with EC50 of 1.7 and 4.6 µg mL-1, respectively. Compound 2 presented low cytotoxicity for J774 macrophages and displayed activity against amastigote forms of L. amazonensis similar to miltefosine with CC50 values of 31.73 and 27.18 µg mL-1, respectively. Additionally, compounds 1 and 2 caused ultrastructural changes in promastigotes leading to a loss of their classical structural morphology, as evidenced by electron microscopy. Also compound 2 decreased the mitochondria membrane potential. To the best of our knowledge, this is the first occurrence of 1 and 2 in C. pinnatifida. The results obtained highlighted the importance of studying sesquiterpene lactones isolated from Calea pinnatifida in terms of antileishmanial activity, in order to understand the mechanism of action of the isolated compounds in promastigotes forms of L. amazonensis.

Antileishmanial activity of meroditerpenoids from the macroalgae Cystoseira baccata.

The development of novel drugs for the treatment of leishmaniases continues to be crucial to overcome the severe impacts of these diseases on human and animal health. Several bioactivities have been described in extracts from macroalgae belonging to the Cystoseira genus. However, none of the studies has reported the chemical compounds responsible for the antileishmanial activity observed upon incubation of the parasite with the aforementioned extracts. Thus, this work aimed to isolate and characterize the molecules present in a hexane extract of Cystoseira baccata that was found to be bioactive against Leishmania infantum in a previous screening effort. A bioactivity-guided fractionation of the C. baccata extract was carried out and the inhibitory potential of the isolated compounds was evaluated via the MTT assay against promastigotes and murine macrophages as well as direct counting against intracellular amastigotes. Moreover, the promastigote ultrastructure, DNA fragmentation and changes in the mitochondrial potential were assessed to unravel their mechanism of action. In this process, two antileishmanial meroditerpenoids, (3R)- and (3S)-tetraprenyltoluquinol (1a/1b) and (3R)- and (3S)-tetraprenyltoluquinone (2a/2b), were isolated. Compounds 1 and 2 inhibited the growth of the L. infantum promastigotes (IC50 = 44.9 ± 4.3 and 94.4 ± 10.1 µM, respectively), inducing cytoplasmic vacuolization and the presence of coiled multilamellar structures in mitochondria as well as an intense disruption of the mitochondrial membrane potential. Compound 1 decreased the intracellular infection index (IC50 = 25.0 ± 4.1 µM), while compound 2 eliminated 50% of the intracellular amastigotes at a concentration > 88.0 µM. This work identified compound 2 as a novel metabolite and compound 1 as a biochemical isolated from Cystoseira algae displaying antileishmanial activity. Compound 1 can thus be an interesting scaffold for the development of novel chemotherapeutic molecules for canine and human visceral leishmaniases studies. This work reinforces the evidence of the marine environment as source of novel molecules.

Antileishmanial Activity and Immunomodulatory Effects of Tricin Isolated from Leaves of Casearia arborea (Salicaceae).

Bioactivity-guided fractionation of antileishmanial active extract from leaves of Casearia arborea led to isolation of three metabolites: tricin (1), 1',6'-di-O-ß-d-vanilloyl glucopyranoside (2) and vanillic acid (3). Compound 1 demonstrated the highest activity against the intracellular amastigotes of Leishmania infantum, with an IC50 value of 56 µm. Tricin (1) demonstrated selectivity in mammalian cells (SI > 7) and elicited immunomodulatory effect on host cells. The present work suggests that tricin modulated the respiratory burst of macrophages to a leishmanicidal state, contributing to the parasite elimination. Therefore, the natural compound tricin could be further explored in drug design studies for leishmaniasis treatment.

Salivary gland homogenates from wild-caught sand flies Lutzomyia flaviscutellata and Lutzomyia (Psychodopygus) complexus showed inhibitory effects on Leishmania (Leishmania) amazonensis and Leishmania (Viannia) braziliensis infection in BALB/c mice.

During the natural transmission of Leishmania parasites, the infected sand fly female regurgitates promastigotes into the host's skin together with its saliva. It has been reported that vector saliva contains immunomodulatory molecules that facilitate the establishment of infection. Thus, the main objective of this study was to evaluate the specificity of Lutzomyia (Lu.) flaviscutellata and Lu. (Psychodopygus) complexus salivas on the infectivity of Leishmania (L.) (Leishmania) amazonensis and L. (Viannia) braziliensis, respectively. BALB/c mice were inoculated into the skin of hind footpad with L. (L.) amazonensis and L. (V.) braziliensis promastigotes in the absence or presence of Lu. flaviscutellata and Lu. (P.) complexus salivary gland homogenates (SGHs). The evolution of the infection was evaluated by lesion size, histopathological analysis and determination of the parasite load in the skin biopsies collected from the site of infection at 4 and 8 weeks PI. The lesion size and the parasite load of both groups of mice infected in the presence of SGHs were smaller than the control groups. The histopathological features showed that the inflammatory reaction was less prominent in the groups of mice infected in the presence of both SGHs when compared to the control group. The results showed that the presence of SGHs of Lu. flaviscutellata and Lu. (P.) complexus led to induction of processes that were disadvantageous to parasite establishment during infection by L. (L.) amazonensis and L. (V.) braziliensis. An inhibitory effect on Leishmania infection could be observed in both groups inoculated with SGHs, especially when the SGH from Lu. (P.) complexus was used.

Treatment with triterpenic fraction purified from Baccharis uncinella leaves inhibits Leishmania (Leishmania) amazonensis spreading and improves Th1 immune response in infected mice.

The current medications used to treat leishmaniasis have many side effects for patients; in addition, some cases of the disease are refractory to treatment. Therefore, the search for new leishmanicidal compounds is indispensable. Recently, it was demonstrated that oleanolic- and ursolic-containing fraction from Baccharis uncinella leaves eliminated the promastigote and amastigote forms of Leishmania (Leishmania) amazonensis and L. (Viannia) braziliensis without causing toxic effects for J774 macrophages. Thus, the aim of the present work was to characterize the therapeutic effect of the triterpenic fraction in L. (L.) amazonensis-infected BALB/c mice. Oleanolic- and ursolic acid-containing fraction was extracted from B. uncinella leaves using organic solvents and chromatographic procedures. L. (L.) amazonensis-infected BALB/c mice were treated intraperitoneally with triterpenic fraction during five consecutive days with 1.0 and 5.0 mg/kg of triterpenic fraction, or with 10.0 mg/kg of amphotericin B drug. Groups of mice treated with the triterpenic fraction, presented with decreased lesion size and low parasitism of the skin-both of which were associated with high amounts of interleukin-12 and interferon gamma. The curative effect of this fraction was similar to amphotericin B-treated mice; however, the final dose, required to eliminate amastigotes, was lesser than amphotericin B. Moreover, triterpenic fraction did not cause microscopic alterations in liver, spleen, heart, lung, and kidney of experimental groups. This work suggests that this fraction possesses compounds that are characterized by leishmanicidal and immunomodulatory activities. From this perspective, the triterpenic fraction can be explored as a new therapeutic agent for use against American Tegumentar Leishmaniasis.

New Immunological Markers in Chromoblastomycosis-The Importance of PD-1 and PD-L1 Molecules in Human Infection.

The pathogenesis of chromoblastomycosis (CBM) is associated with Th2 and/or T regulatory immune responses, while resistance is associated with a Th1 response. However, even in the presence of IFN-γ, fungi persist in the lesions, and the reason for this persistence is unknown. To clarify the factors associated with pathogenesis, this study aimed to determine the polarization of the cellular immune response and the densities of cells that express markers of exhaustion in the skin of CBM patients. In the skin of patients with CBM, a moderate inflammatory infiltrate was observed, characterized primarily by the occurrence of histiocytes. Analysis of fungal density allowed us to divide patients into groups that exhibited low and high fungal densities; however, the intensity of the inflammatory response was not related to mycotic loads. Furthermore, patients with CBM exhibited a significant increase in the number of CD4+ and CD8+ cells associated with a high density of IL-10-, IL-17-, and IFN-γ-producing cells, indicating the presence of a chronic and mixed cellular immune response, which was also independent of fungal load. A significant increase in the number of PD-1+ and PD-L1+ cells was observed, which may be associated with the maintenance of the fungus in the skin and the progression of the disease.

Primary Cutaneous Cryptococcosis Caused by Cryptococcus gatti in an Elderly Patient.

According to the spread of Cryptococcus sp., fungal infections can be classified as primary or secondary. In primary cutaneous cryptococcosis, the fungi are restricted to the skin of the patients, without systemic involvement. The incidence of primary cutaneous cryptococcosis is high in patients with immunosuppression, and this type of infection is rarely observed in patients who are immunocompetent. In the present case report, a patient who is immunocompetent and has systemic comorbidity reported that, after skin trauma, ulcerovegetative lesions appeared in the right upper arm; the etiologic agent was identified as Cryptococcus gatti, serotype B. The cutaneous lesions healed completely after 5 months of fluconazole treatment.

Absolute Configuration and Antileishmanial Activity of (-)-Cyclocolorenone Isolated from Duguetia lanceolata (Annonaceae).

BACKGROUND: The fractionation of the n-hexane phase of the EtOH extract from the leaves of Duguetia lanceolata (Annonaceae) led to the identification of the sesquiterpene (-)-cyclocolorenone. OBJECTIVES: Chemical characterization, including determination of the absolute stereochemistry, and in vitro evaluation of antileishmanial activity of the sesquiterpene (-)-cyclocolorenone, isolated from D. lanceolata, were carried out. METHODS: (-)-Cyclocolorenone was isolated from D. lanceolata leaves using different chromatographic steps and its structure was defined by analysis of NMR and ESI-HRMS data. Additionally, the absolute configuration of (-)-cyclocolorenone was ambiguously assigned by means of vibrational circular dichroism (VCD). Antileishmanial activity of (-)-cyclocolorenone was evaluated on promastigote and amastigote forms of Leishmania (Leishmania) amazonensis. The integrity of the cell membrane of L. (L.) amazonensis was analyzed using the SYTOX green probe. RESULTS: (-)-(1R,6S,7R,10R)-Cyclocolorenone displayed activity against promastigotes and amastigotes forms of L. (L.) amazonensis with IC50 of 4.54 and 28.44 µM, respectively. Furthermore, this compound was non-toxic in J774 macrophage cells (CC50 > 458.71 µM) with a selectivity index > 100 (promastigotes) and > 32.2 (amastigotes). Additionally, (-)-cyclocolorenone was observed to target the parasite cell membrane. CONCLUSION: Obtained data suggested that (-)-cyclocolorenone, in which absolute configuration was determined, can be considered as a scaffold for the development of new drugs for the treatment of leishmaniasis.

Anti-leishmanial effects of purified compounds from aerial parts of Baccharis uncinella C. DC. (Asteraceae).

Species of Baccharis exhibit antibiotic, antiseptic, wound-healing, and anti-protozoal properties, and have been used in the traditional medicine of South America for the treatment of several diseases. In the present work, the fractionation of EtOH extract from aerial parts of Baccharis uncinella indicated that the isolated compounds caffeic acid and pectolinaringenin showed inhibitory activity against Leishmania (L.) amazonensis and Leishmania (V.) braziliensis promastigotes, respectively. Moreover, amastigote forms of both species were highly sensible to the fraction composed by oleanolic + ursolic acids and pectolinaringenin. Caffeic acid also inhibited amastigote forms of L. (L.) amazonensis, but this effect was weak in L. (V.) braziliensis amastigotes. The treatment of infected macrophages with these compounds did not alter the levels of nitrates, indicating a direct effect of the compounds on amastigote stages. The results presented herein suggest that the active components from B. uncinella can be important to the design of new drugs against American tegumentar leishmaniases.

Evaluation of anti-inflammatory activity of derivatives from aerial parts of Baccharis uncinella.

CONTEXT: Species of Baccharis exhibit antibiotic, antiseptic, and wound-healing properties, and have been used in the traditional medicine of South America for the treatment of inflammation, headaches, diabetes, and hepatobiliary disorders. OBJECTIVE: To investigate the anti-inflammatory activity of organic phases from EtOH extract of the aerial parts of Baccharis uncinella DC (Asteraceae). MATERIALS AND METHODS: The crude EtOH extract from the aerial parts of B. uncinella was subjected to partition procedures and the corresponding CH(2)Cl(2) and EtOAc phases were subjected to several chromatographic separation procedures. Thus, these phases and their purified compounds were assayed for evaluation of anti-inflammatory activity. RESULTS: The CH(2)Cl(2) phase from EtOH extract from B. uncinella contained two triterpenoids (oleanolic and ursolic acids) and one flavonoid (pectolinaringenin), whereas the respective EtOAc phase showed to be composed mainly by two phenylpropanoid derivatives (caffeic and ferulic acids). The CH(2)Cl(2) and EtOAc phases as well as their isolated compounds exhibited anti-inflammatory effects against inflammatory reactions induced by phospholipase A2 (from Crotalus durissus terrificus venom) and by carrageenan. DISCUSSION AND CONCLUSION: The results suggested that the components obtained from partition phases of EtOH extract of B. uncinella could represent lead molecules for the development of anti-inflammatory agents. Additionally, the results confirmed the use of Baccharis genus in the traditional medicine of South America for the treatment of inflammation and other heath disorders. To date, the present work describes for the first time the anti-inflammatory effects of compounds isolated from B. uncinella.

The Potential of Traditional Knowledge to Develop Effective Medicines for the Treatment of Leishmaniasis.

Leishmaniasis is a neglected tropical disease that affects people living in tropical and subtropical areas of the world. There are few therapeutic options for treating this infectious disease, and available drugs induce severe side effects in patients. Different communities have limited access to hospital facilities, as well as classical treatment of leishmaniasis; therefore, they use local natural products as alternative medicines to treat this infectious disease. The present work performed a bibliographic survey worldwide to record plants used by traditional communities to treat leishmaniasis, as well as the uses and peculiarities associated with each plant, which can guide future studies regarding the characterization of new drugs to treat leishmaniasis. A bibliographic survey performed in the PubMed and Scopus databases retrieved 294 articles related to traditional knowledge, medicinal plants and leishmaniasis; however, only 20 were selected based on the traditional use of plants to treat leishmaniasis. Considering such studies, 378 quotes referring to 292 plants (216 species and 76 genera) that have been used to treat leishmaniasis were recorded, which could be grouped into 89 different families. A broad discussion has been presented regarding the most frequent families, including Fabaceae (27 quotes), Araceae (23), Solanaceae and Asteraceae (22 each). Among the available data in the 378 quotes, it was observed that the parts of the plants most frequently used in local medicine were leaves (42.3% of recipes), applied topically (74.6%) and fresh poultices (17.2%). The contribution of Latin America to studies enrolling ethnopharmacological indications to treat leishmaniasis was evident. Of the 292 plants registered, 79 were tested against Leishmania sp. Future studies on leishmanicidal activity could be guided by the 292 plants presented in this study, mainly the five species Carica papaya L. (Caricaceae), Cedrela odorata L. (Meliaceae), Copaifera paupera (Herzog) Dwyer (Fabaceae), Musa × paradisiaca L. (Musaceae), and Nicotiana tabacum L. (Solanaceae), since they are the most frequently cited in articles and by traditional communities.

Nanoemulsified Butenafine for Enhanced Performance against Experimental Cutaneous Leishmaniasis.

The production of ergosterol lipid involves the activity of different enzymes and is a crucial event for the Leishmania membrane homeostasis. Such enzymes can be blocked by azoles and allylamines drugs, such as the antifungal butenafine chloride. This drug was active on parasites that cause cutaneous and visceral leishmaniasis. Based on the leishmanicidal activity of butenafine chloride and considering the absence of reports about the therapeutic potential of this drug in cutaneous leishmaniasis, the present work is aimed at analyzing the efficacy of butenafine formulated in two different topical delivery systems, the self-nanoemulsifying drug delivery systems (BUT-SNEDDS) and in a SNEDDS-based nanogel (BUT-SNEDDS gel) as well as in the free form in experimental cutaneous leishmaniasis. Physical studies showed that both formulations were below 300 nm with low polydispersity (<0.5) and good colloidal stability (around -25 mV). Increased steady-state flux was reported for nanoenabled butenafine formulations with reduced lag time in Franz cell diffusion assays across Strat-M membranes. No toxic or inflammatory reactions were detected in animals treated with BUT-SNEDDS, BUT-SNEDDS gel, or butenafine. Animals topically treated with butenafine (free or nanoformulated) showed small dermal lesions and low tissue parasitism. Furthermore, BUT-SNEDD gel and butenafine presented similar efficacy than the standard drug Glucantime given by the intralesional route. Increased levels of IFN-γ were observed in animals treated with BUT-SNEDDS gel or butenafine. Based on these data, the antifungal drug butenafine chloride can be considered an interesting repurposed drug for the treatment of cutaneous leishmaniasis.

Antileishmanial activity and ultrastructural changes of related tetrahydrofuran dineolignans isolated from Saururus cernuus L. (Saururaceae).

OBJECTIVE: This work describes the isolation of anti-Leishmania amazonensis metabolites from Saururus cernuus (Saururaceae). Additionally, ultrastructural changes in promastigotes were evidenced by electron microscopy. METHODS: The MeOH extract from the leaves of S. cernuus was subjected to bioactivity-guided fractionation. Anti-L. amazonensis activity of purified compounds was performed in vitro against promastigote and amastigote forms. KEY FINDINGS: Bioactivity-guided fractionation of the MeOH extract from the leaves of S. cernuus afforded two related tetrahydrofuran dineolignans: threo,threo-manassantin A (1) and threo,erythro-manassantin A (2). Compounds 1 and 2 displayed activity against promastigotes (EC50 of 35.4 ± 7.7 and 17.6 ± 4.2 µm, respectively) and amastigotes (EC50 of 20.4 ± 1.9 and 16.0 ± 1.1 µm, respectively), superior to that determined for the positive control miltefosine (EC50 of 28.7 ± 3.5 µm). Reduced cytotoxicity for host cells was observed for both compounds. Additionally, ultrastructural changes in promastigotes leading to an alteration of structural morphology were observed, as evidenced by electron microscopy. Furthermore, these compounds altered the morphology and physiology of the plasmatic membrane of L. amazonensis. CONCLUSIONS: The obtained results indicated that dineolignans 1 and 2 could be considered as a scaffold for the design of novel and selective drug candidates for the treatment of leishmaniasis.

Effect of phospholipase A2 inhibitors during infection caused by Leishmania (Leishmania) amazonensis.

BACKGROUND: Lipid metabolites play an important role in parasite differentiation and virulence. Studies have revealed that Leishmania sp. uses prostaglandins to evade innate barriers, thus enabling the parasites to survive inside immune cells. Despite the role of the enzyme Phospholipase A2 (PLA2) in prostaglandins production, few studies have investigated the role of parasite PLA2 during the interaction between L. (L.) amazonensis and the host (in vitro and in vivo) immune cells. METHODS: In the present work, the leishmanicidal effect of PLA2 inhibitors, methyl arachidonyl fluorophosphonate (MAFP), bromoenol lactone (BEL) and aristolochic acid (AA) were investigated in vitro (promastigote and intracellular amastigote forms of L. (L.) amazonensis) and during in vivo infection using BALB/c mice. RESULTS: The aforementioned inhibitors were deleterious to promastigote and amastigote forms of the L. (L.) amazonensis and were non-toxic to peritoneal macrophages from BALB/c mice. L. (L.) amazonensis-infected BALB/c mice treated with the inhibitor BEL presented decreased lesion size and skin parasitism; however, BEL treatment induced hepatotoxicity in BALB/c mice. CONCLUSIONS: Results presented herein suggested that PLA2 inhibitors altered L. (L.) amazonensis viability. In spite of liver toxicity, treatment with BEL was the most selective compound in vitro, as well in vivo, resulting in lower skin parasitism in the infected mice. These findings corroborate the role of PLA2 in parasite virulence and maintenance in vertebrate hosts, and suggest that molecules structurally related to BEL should be considered when planning compounds against Leishmania sp.

Correction: p16INK4a Expression and Immunologic Aging in Chronic HIV Infection.

[This corrects the article DOI: 10.1371/journal.pone.0166759.].

Therapeutic effect of ursolic acid in experimental visceral leishmaniasis.

Leishmaniasis is an important neglected tropical disease, affecting more than 12 million people worldwide. The available treatments are not well tolerated and present diverse side effects in patients, justifying the search for new therapeutic compounds. In the present study, the therapeutic potential and toxicity of ursolic acid (UA), isolated from the leaves of Baccharis uncinella C. DC. (Asteraceae), were evaluated in experimental visceral leishmaniasis. To evaluate the therapeutic potential of UA, hamsters infected with L. (L.) infantum were treated daily during 15 days with 1.0 or 2.0 mg UA/kg body weight, or with 5.0 mg amphotericin B/kg body weight by intraperitoneal route. Fifteen days after the last dose, the parasitism of the spleen and liver was stimated and the main histopathological alterations were recorded. The proliferation of splenic mononuclear cells was evaluated and IFN-γ, IL-4, and IL-10 gene expressions were analyzed in spleen fragments. The toxicity of UA and amphotericin B were evaluated in healthy golden hamsters by histological analysis and biochemical parameters. Animals treated with UA had less parasites in the spleen and liver when compared with the infected control group, and they also showed preservation of white and red pulps, which correlate with a high rate of proliferation of splenic mononuclear cells, IFN-γ mRNA and iNOS production. Moreover, animals treated with UA did not present alterations in the levels of AST, ALT, creatinine and urea. Taken together, these findings indicate that UA is an interesting natural compound that should be considered for the development of prototype drugs against visceral leishmaniasis.

The antifungal compound butenafine eliminates promastigote and amastigote forms of Leishmania (Leishmania) amazonensis and Leishmania (Viannia) braziliensis.

The production of ergosterol lipid, important for the Leishmania membrane homeostasis, involves different enzymes. This pathway can be blocked to azoles and allylamines drugs, such as Butenafine. The aim of the present work was to evaluate the anti-leishmanicidal activity of this drug in 2 major species of Leishmania responsible for causing the American tegumentar leishmaniasis (L. (L.) amazonensis and L. (V.) braziliensis). Butenafine eliminated promastigote forms of L. amazonensis and L. braziliensis with efficacy similar to miltefosine, a standard anti-leishmania drug. In addition, butenafine induced alterations in promastigote forms of L. amazonensis that resemble programmed cell death. Butenafine as well as miltefosine presented mild toxicity in peritoneal macrophages, however, butenafine was more effective to eliminate intracellular amastigotes of both L. amazonensis and L. braziliensis, and this effect was not associated with elevated levels of nitric oxide or hydrogen peroxide. Taken together, data presented herein suggests that butenafine can be considered as a prototype drug able to eliminate L. amazonensis and L. braziliensis, etiological agents of anergic diffuse and mucocutaneous leishmaniasis, respectively.