Antileismanial activity,mechanism of action study and molecular docking of 1,4‐bis(substituted benzalhydrazino)phthalazines

To identify new agents for the treatment of American cutaneous leishmaniasis, a series of eight 1,4‐bis(substituted benzalhydrazino)phthalazines was evaluated against Leishmania braziliensis and Leishmania mexicana parasites. These compounds represent a disubstituted version of the 1‐chloro‐4‐(monoaryl/heteroarylhydranizyl)phthalazine that exhibited a significant response against L. braziliensis according to our previous findings. Two disubstituted phthalazines 3b and 3f were identified as potential antileishmanial agents against L. braziliensis parasites, exhibiting a submicromolar IC₅₀ response of 2.37 and 7.90 µM on the promastigote form, and of 1.82 and 4.56 µM against intracellular amastigotes, respectively. In particular, compound 3b showed interesting responses against amastigote isolates from reference, glucantime‐resistant and clinical human strains, which were by far superior to the biological response found for the glucantime drug. With regard to the toxicity results, both 3b and 3f exhibited moderate LD₅₀ values against murine macrophages (BMDM), with good selectivity indexes on promastigotes and intracellular amastigotes of L. braziliensis. A comparison of biological response was established between the monosubstituted and disubstituted versions of these benzalhydrazino‐phthalazines. Easy synthetic procedure and significant response against amastigote strains including against resistant lines made compound 3b a potential candidate for further pharmacokinetic and in vivo experiments as antileishmanial agent, and as a platform for further structural optimization. Mechanism‐of‐action studies and molecular docking simulations discarded to inhibition of superoxide dismutase as possible mode of action.     

Design,synthesis and antitrypanosomatid activities of 3,5‐diaryl‐isoxazole analogues based on neolignans veraguensin,grandisin and machilin G

Using bioisosterism as a medicinal chemistry tool, 16 3,5‐diaryl‐isoxazole analogues of the tetrahydrofuran neolignans veraguensin, grandisin and machilin G were synthesized via 1,3‐dipolar cycloaddition reactions, with yields from 43% to 90%. Antitrypanosomatid activities were evaluated against Trypanosoma cruzi, Leishmania (L.) amazonensis and Leishmania (V.) braziliensis. All compounds were selective for the Leishmania genus and inactive against T. cruzi. Isoxazole analogues showed a standard activity on both promastigotes of L. amazonensis and L. braziliensis. The most active compounds were 15 , 16 and 19 with IC₅₀ values of 2.0, 3.3 and 9.5 μM against L. amazonensis and IC₅₀ values of 1.2, 2.1 and 6.4 μM on L. braziliensis, respectively. All compounds were noncytotoxic, showing lower cytotoxicity (>250 μM) than pentamidine (78.9 μM). Regarding the structure–activity relationship (SAR), the methylenedioxy group was essential to antileishmanial activity against promastigotes. Replacement of the tetrahydrofuran nucleus by an isoxazole core improved the antileishmanial activity.     

Synthesis and leishmanicidal evaluation of sulfanyl- and sulfonyl-tethered functionalized benzoate derivatives featuring a nitroimidazole moiety

A series of new nitroimidazole-containing derivatives was synthesized by coupling of 2-[2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethylthio]ethanol with diversely substituted benzoic acids. Upon treatment with m-CPBA, 12 of these sulfanyl compounds were further oxidized to their sulfonyl analogs. All the 26 synthetic compounds were examined for in vitro activity against Leishmania (V.) braziliensis and Leishmania (L.) mexicana, and some of them displayed an efficient antileishmanial activity. Among the compounds tested, the catecholic derivative 2-{[2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethyl]sulfanyl}ethyl 3,4-dihydroxybenzoate ( 9a , LC₅₀ = 13 and 11 µM) and the pyrogallolic derivative 2-{[2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethyl]sulfanyl}ethyl 3,4,5-trihydroxybenzoate ( 9b , LC₅₀ = 4 and 1 µM) were the most active ones against the two Leishmania strains.     

7‐Chloro‐4‐quinolinyl Hydrazones: A Promising and Potent Class of Antileishmanial Compounds

In this work, we report the antileishmanial evaluation of twenty 7‐chloro‐4‐quinolinyl hydrazone derivatives ( 1 – 20 ). Firstly, the compounds were tested against promastigotes of four different Leishmania species. After that, all derivatives were assayed against L. braziliensis amastigotes and murine macrophages. Furthermore, it was investigated whether the antiamastigote L. braziliensis effect of the compounds could be associated with nitric oxide production. Compounds 6 and 7 showed a strong leishmanicidal activity against intracellular parasite with IC₅₀ in nanogram levels (30 and 20 ng/mL, respectively). Appreciable activity of three compounds tested can be considered an important finding for the rational design of new leads for antileishmanial compounds.     

Assessment of Leishmanicidal and Trypanocidal Activities of Aliphatic Diamine Derivatives

Leishmanicidal and trypanocidal activity of seventeen lipophilic diamines was evaluated in vitro against Leishmania braziliensis, L. chagasi, and Trypanosoma cruzi. Twelve compounds presented anti‐Leishmania and six showed anti‐T. cruzi amastigote activity. Compound 14 (N‐tetradecyl‐1,4‐butanediamine) was the most active against both L. braziliensis (IC₅₀ = 2.6 μm ) and L. chagasi (IC₅₀ = 3.0 μm ) which showed a selectivity index (SI) >100. N‐decyl‐1,6‐hexanediamine (compound 9 ) presented an IC₅₀ = 1.6 μm and SI >187 and was over six times more potent than the reference drug benznidazole against T. cruzi. Treatment of infected or uninfected macrophages with compounds 9 and 14 did not induce significant TNFα and NO production. Four compounds ( 15 , 16 , 22 , and 23 ) inhibited 78.9%, 77.7%, 83.7%, and 70.1% of rTRLb activity, respectively, and compound 23 inhibited 73.3% of rTRTc activity at 100 μm . A concentration‐dependent effect on mitochondrial membrane depolarization was observed in T. cruzi epimastigotes treated with compound 9 , suggesting this mechanism may be involved in the trypanocidal effect. On the contrary, in L. braziliensis promastigotes treated with compound 14 , no mitochondrial depolarization was observed. Our results demonstrate that N‐decyl‐1,6‐hexanediamine and N‐tetradecyl‐1,4‐butanediamine are promising molecules for the development of novel leading compounds against T. cruzi and Leishmania spp., particularly given a possible alternative mechanism of action.     

Design,synthesis, and in vitro biological evaluation of novel thiazolopyrimidine derivatives as antileishmanial compounds

A series of thiazolopyrimidine derivatives was designed and synthesized as a Leishmania major pteridine reductase 1 (LmPTR1) enzyme inhibitor. Their LmPTR1 inhibitor activities were evaluated using the enzyme produced by Escherichia coli in a recombinant way. The antileishmanial activity of the selected compounds was tested in vitro against Leishmania sp. Additionally, the compounds were evaluated for cytotoxic activity against the murine macrophage cell line RAW 264.7. According to the results, four compounds displayed not only a potent in vitro antileishmanial activity against promastigote forms but also low cytotoxicity. Among them, compound L16 exhibited an antileishmanial activity for both the promastigote and amastigote forms of L. tropica, with IC₅₀ values of 7.5 and 2.69 µM, respectively. In addition, molecular docking studies and molecular dynamics simulations were also carried out in this study. In light of these findings, the compounds provide a new potential scaffold for antileishmanial drug discovery.     

Synthesis,Cytotoxicity and In Vitro Antileishmanial Activity of Naphthothiazoles

The leishmaniasis is a spectral disease caused by the protozoan Leishmania spp., which threatens millions of people worldwide. Current treatments exhibit high toxicity, and there is no vaccine available. The need for new lead compounds with leishmanicidal activity is urgent. Considering that many lead leishmanicidal compounds contain a quinoidal scaffold and the thiazole heterocyclic ring is found in a number of antimicrobial drugs, we proposed a hybridization approach to generate a diverse set of semi‐synthetic heterocycles with antileishmanial activity. We found that almost all synthesized compounds demonstrated potent activity against promastigotes of Leishmania (Viannia) braziliensis and reduced the survival index of Leishmania amastigotes in mammalian macrophages. Furthermore, the compounds were not cytotoxic to macrophages at fivefold higher concentrations than the EC₅₀ for promastigotes. All molecules fulfilled Lipinski's Rule of Five, which predicts efficient orally absorption and permeation through biological membranes, the in silico pharmacokinetic profile confirmed these characteristics. The potent and selective activity of semi‐synthetic naphthothiazoles against promastigotes and amastigotes reveals that the 2‐amino‐naphthothiazole ring may represent a scaffold for the design of compounds with leishmanicidal properties and encourage the development of drug formulation and new compounds for further studies in vivo.     

Dillapiole as Antileishmanial Agent: Discovery,Cytotoxic Activity and Preliminary SAR Studies of Dillapiole Analogues

In this paper, the isolation of dillapiole ( 1 ) from Piper aduncum was reported as well as the semi‐synthesis of two phenylpropanoid derivatives [di‐hydrodillapiole ( 2 ), isodillapiole ( 3 )], via reduction and isomerization reactions. Also, the compounds' molecular properties (structural, electronic, hydrophobic, and steric) were calculated and investigated to establish some preliminary structure–activity relationships (SAR). Compounds were evaluated for in vitro antileishmanial activity and cytotoxic effects on fibroblast cells. Compound 1 presented inhibitory activity against Leishmania amazonensis (IC₅₀ = 69.3 µM) and Leishmania brasiliensis (IC₅₀ = 59.4 µM) and induced cytotoxic effects on fibroblast cells mainly in high concentrations. Compounds 2 (IC₅₀ = 99.9 µM for L. amazonensis and IC₅₀ = 90.5 µM for L. braziliensis) and 3 (IC₅₀ = 122.9 µM for L. amazonensis and IC₅₀ = 109.8 µM for L. brasiliensis) were less active than dillapiole ( 1 ). Regarding the molecular properties, the conformational arrangement of the side chain, electronic features, and the hydrophilic/hydrophobic balance seem to be relevant for explaining the antileishmanial activity of dillapiole and its analogues.     

Discovery of Synthetic Leishmania Inhibitors by Screening of a 2‐Arylbenzothiophene Library

Tamoxifen has been shown to be active in vitro against Leishmania and effective in the treatment for leishmaniasis in murine models. Through the screening of a compound library of estrogen receptor modulator analogs, we identified the major characteristics required for antileishmanial activity. To overcome the difficulties presented by tamoxifen's propensity for E/Z isomerization, we used the 2‐arylbenzothiophene compound BTP as a more stable alternative. Directed screening of a small compound library based on BTP led to active compounds against Leishmania. Subsequent structure–activity data for the synthetic 2‐arylbenzothiophenes evaluated in this study indicate that optimal antileishmanial potency is dependent on the presence of two basic side chains. In addition, the primary structural features required for estrogen receptor binding, the phenols, are not required for inhibiting parasitic growth. Significantly, the most active antileishmanial benzothiophenes lack the pharmacophore for estrogen receptor activity and therefore address potential concerns about the undesirable effects of using selective estrogen receptor modulators in women and children with leishmaniasis. Three compounds selected from the screening have shown consistent activity against all species and stages of Leishmania in vitro although improvements in selectivity are needed. These compounds represent viable starting points for further optimization as antileishmanial agents.     

1,3‐Bis(aryloxy)propan‐2‐ols as potential antileishmanial agents

We describe herein the synthesis and antileishmanial activity of 1,3‐bis(aryloxy)propan‐2‐ols. Five compounds ( 2 , 3 , 13 , 17 , and 18 ) exhibited an effective antileishmanial activity against stationary promastigote forms of Leishmania amazonensis (IC₅₀ < 15.0 μm ), and an influence of compound lipophilicity on activity was suggested. Most of the compounds were poorly selective, as they showed toxicity toward murine macrophages, except 17 and 18 , which presented good selective indexes (SI ≥ 10.0). The five more active compounds ( 2 , 3 , 13 , 17 , and 18 ) were selected for the treatment of infected macrophages, and all of them were able to reduce the number of internalized parasites by more than 80%, as well as the number of infected macrophages by more than 70% in at least one of the tested concentrations. Altogether, these results demonstrate the potential of these compounds as new hits of antileishmanial agents and open future possibilities for them to be tested in in vivo studies.     

Discovery of benzimidazole‐based Leishmania mexicana cysteine protease CPB2.8ΔCTE inhibitors as potential therapeutics for leishmaniasis

Chemotherapy is currently the only effective approach to treat all forms of leishmaniasis. However, its effectiveness is severely limited due to high toxicity, long treatment length, drug resistance, or inadequate mode of administration. As a consequence, there is a need to identify new molecular scaffolds and targets as potential therapeutics for the treatment of this disease. We report a small series of 1,2‐substituted‐1H‐benzo[d]imidazole derivatives ( 9a–d ) showing affinity in the submicromolar range (K_i = 0.15–0.69 μM) toward Leishmania mexicanaCPB2.8ΔCTE, one of the more promising targets for antileishmanial drug design. The compounds confirmed activity in vitro against intracellular amastigotes of Leishmania infantum with the best result being obtained with derivative 9d (IC₅₀ = 6.8 μM), although with some degree of cytotoxicity (CC₅₀ = 8.0 μM on PMM and CC₅₀ = 32.0 μM on MCR‐5). In silico molecular docking studies and ADME‐Tox properties prediction were performed to validate the hypothesis of the interaction with the intended target and to assess the drug‐likeness of these derivatives.     

Screening of medicinal plants against Leishmania amazonensis

Context: Leishmaniasis is a widespread tropical infection caused by different species of Leishmania protozoa. There is no immunoprophylaxis (vaccination) available for Leishmania infections and conventional treatments are unsatisfactory; therefore antileishmanial drugs are urgently needed. Natural products are attractive due to their structural diversity.

Objective: The present work investigated the antileishmanial action of 21 species of plants.

Materials and methods: Plants were collected and their hydroalcoholic extracts were screened against promastigotes and amastigotes of L. amazonensis. Their toxicity was also assayed against peritoneal macrophages from BALB/c mice.

Results: Five extracts showed significant growth inhibitory activity against promastigote form. Only the extracts from Bidens pilosa L. (Asteraceae) and Punica granatum L. (Punicaceae) inhibited the growth of intracellular amastigotes, with IC₅₀ values of 42.6 and 69.6 µg/mL, respectively. In addition, a low toxicity on macrophage from BALB/c mice was observed.

Discussion: The antiparasitic activities of B. pilosa and P. granatum have been reported against other parasitic agents and their actions can be the results of flavonoids present in the extracts.

Conclusion: This study supports the importance of natural products as potential sources in the search for new antileishmanial drugs.     

Effect of 3‐Alkylpyridine Marine Alkaloid Analogues in Leishmania Species Related to American Cutaneous Leishmaniasis

A series of oxygenated analogues of marine 3‐alkylpyridine alkaloids were synthesized, and their leishmanicidal activity was assayed. All compounds were prepared from 3‐pyridinepropanol in few steps and in good yields. The key step for the synthesis of these compounds was a classic Williamson etherification under phase‐transfer conditions. Besides toxicity in peritoneal macrophages, the compounds exhibited a significant leishmanicidal activity. Of twelve compounds tested, five showed a strong leishmanicidal activity against promastigote forms of Leishmania amazonensis and L. braziliensis with IC₅₀ below 10 μm . Compounds 11 , 14 , 15, and 16 showed a strong leishmanicidal activity on intracellular amastigotes (IC₅₀ values of 2.78; 0.27; 1.03, and 1.33 μm , respectively), which is unlikely to be owing to the activation of nitric oxide production by macrophages.     

Antileishmanial Activity,Cytotoxicity and Mechanism of Action of Clioquinol Against Leishmania infantum and Leishmania amazonensis Species

In this study, a quinoline derivate, clioquinol (5‐chloro‐7‐iodoquinolin‐8‐ol), was evaluated against Leishmania amazonensis and Leishmania infantum promastigotes and amastigotes. The cytotoxicity in murine macrophages and human red blood cells, as well as the efficacy in treating infected macrophages and the inhibition of infection using pre‐treated parasites were also evaluated. Results showed that clioquinol inhibited L. amazonensis and L. infantum promastigotes with effective concentration 50% (EC₅₀) values of 2.55 ± 0.25 and 1.44 ± 0.35 μg/mL, respectively, and of 1.88 ± 0.13 and 0.98 ± 0.17 μg/mL against axenic amastigotes, respectively. The cytotoxic EC₅₀ concentrations of clioquinol in murine macrophages and human red blood cells were, respectively, 255 ± 23 and 489 ± 20 μg/mL. With these results, the selectivity index was calculated, showing values of 99.9 and 177.1 against promastigotes, respectively, and of 135.6 and 260.1 against axenic amastigotes, respectively. Significant reductions in the percentage of infected macrophages after treatment using clioquinol were also observed, as well as when parasites were pre‐treated with clioquinol and used to infect murine macrophages. The mechanism of action of clioquinol was investigated in L. amazonensis, and results revealed morphological and biochemical alterations in the clioquinol‐treated parasites, including reduction in cell volume, loss of mitochondrial membrane potential, increase in the ROS production and rupture of the plasma membrane. The externalization of phosphatidylserine (PS) at the cell surface was evaluated in treated parasites that had been doubly labelled with annexin and propidium iodide (PI). The results showed no significant difference for PS exposure when compared to the untreated control, although a significant increase in the PI/annexin V‐labelled cell population was found in the treated parasites. Results suggest that clioquinol induces a discontinuity of the parasite membrane, possibly related to a characteristic event of cell death caused by necrosis. This study demonstrates, for the first time, the antileishmanial activity of clioquinol against two relevant Leishmania species and suggests that the mitochondria of the parasites may be a possible biological target leading to parasite necrosis. Our findings suggest that clioquinol may have a potential application in treatment of leishmaniasis and further studies should be performed in infected mammalian hosts.     

Effect of a Bis(Benzyl)Polyamine Analogue, and DL-α-difluoromethylornithine on Parasite Suppression and Cellular Polyamine Levels in Golden Hamster During Leishmania Donovani Infection

We examined the antileishmanial activity of DL-α-difluoromethylornithine (DFMO) and a bis(benzyl)polyamine analogue (MDL 27695; N,N′-bis{3[(phenyl-methyl)amino] propyl} 1,7-diaminoheptane) in L. donovani infected golden hamsters. DFMO, an enzyme activated irreversible inhibitor of ornithine decarboxylase, the rate limiting enzyme in polyamine biosynthesis, has potent antileishmanial activity. When given as a 2% solution in drinking water 2 days after infection and continued for 4 days, it suppressed liver parasites by 90% and spleen parasites by 99%. Liver parasites were suppressed by 50% and spleen parasites by 77% in L. donovani infected hamsters when treated three times per day for 4 days with a total dose of 60 mg kg^-1 body weight of MDL 27695. The polyamine content of the liver and spleen of hamsters was determined after 8 days of L. donovani infection and also after treatment with these drugs. Putrescine and spermidine levels increased significantly in both liver and spleen after Leishmania infection of golden hamsters. Treatment with drugs that inhibit the growth of Leishmania amstigotes in the liver and spleen of golden hamsters also reduced polyamine levels of previously infected golden hamsters. There is a close correlation between the therapeutic activity of the drugs and the polyamine content.     

Trypanocidal and leishmanicidal activities of flavonoids isolated from Stevia satureiifolia var. satureiifolia

Context Chagas’ disease and leishmaniasis produce significant disability and mortality with great social and economic impact. The genus Stevia (Asteraceae) is a potential source of antiprotozoal compounds.

Objective Aerial parts of four Stevia species were screened on Trypanosoma cruzi. Stevia satureiifolia (Lam.) Sch. Bip. var. satureiifolia (Asteraceae) dichloromethane extract was selected for a bioassay-guided fractionation in order to isolate its active compounds. Additionally, the antileishmanial activity and the cytotoxicity of these compounds on mammalian cells were assessed.

Materials and methods The dichloromethane extract was fractionated by column chromatography. The isolated compounds were evaluated using concentrations of 0–100?μg/mL on T. cruzi epimastigotes and on Leishmania braziliensis promastigotes for 72?h, on trypomastigotes and amastigotes of T. cruzi for 24?h and 120?h, respectively. The compounds’ cytotoxicity (12.5–500?μg/mL) was assessed on Vero cells by the MTT assay. The structure elucidation of each compound was performed by spectroscopic methods and HPLC analysis.

Results The dichloromethane extracts of Stevia species showed significant activity on T. cruzi epimastigotes. The flavonoids eupatorin (1.3%), cirsimaritin (1.9%) and 5-desmethylsinensetin (1.5%) were isolated from S. satureiifolia var. satureiifolia extract. Eupatorin and 5-desmethylsinensetin showed IC₅₀ values of 0.2 and 0.4?μg/mL on T. cruzi epimastigotes and 61.8 and 75.1?μg/mL on trypomastigotes, respectively. The flavonoid 5-desmethylsinensetin showed moderate activity against T. cruzi amastigotes (IC_50? value?=_?78.7?μg/mL) and was the most active compound on L. braziliensis promastigotes (IC_50? value?=_?37.0?μg/mL). Neither of the flavonoids showed cytotoxicity on Vero cells, up to a concentration of 500?μg/mL.     

Identification of dehydroxy isoquine and isotebuquine as promising anticancer agents targeting K+ channel

Traditional antimalarial drugs based on 4‐aminoquinolines have exhibited good antiproliferative activities against human tumor cells; however, their low relative efficacy has limited their corresponding clinical uses. In order to identify new potent anticancer agents based on 4‐aminoquinoline, we evaluated the antiproliferative activity of a series of dehydroxy isoquines and isotebuquines against five human cancer lines. HeLa and SKBr3 were significantly more sensitive to the action of tested quinolines than the A549, MCF‐7, and PC‐3 cancer lines. Compound 2h was by far the most potent derivative against four of the tested lines (except to PC3 line), exhibiting low micromolar or nanomolar IC₅₀ values superior to adriamycin reference, low toxicities on dermis human fibroblasts (LD₅₀ > 250 μM), and excellent selectivity indexes against the mentioned cancer cells. A structure–activity relationship analysis put in evidence that a pyrrolidine or morpholine moiety as N‐alkyl terminal substitution and the incorporation of the extra phenyl attached to aniline ring are pharmacophore essentials for improvement the anticancer activity of the studied dehydroxy isoquines and isotebuquines. From the results, compound 2h emerged as a promising anticancer candidate for further in vitro assays against resistant‐strain and in vivo studies as well as pharmacokinetic and genotoxicity studies. Mechanistic assays suggested that the most active quinoline 2h act as calcium‐activated potassium channel activator.     

In Vitro Effects of the Neolignan 2,3‐Dihydrobenzofuran Against Leishmania Amazonensis

Leishmaniasis is an infectious disease complex caused by protozoa from the Leishmania genus, which presents a broad spectrum of clinical manifestations: cutaneous, mucocutaneous and visceral forms. The current treatments are unsatisfactory considering that few drugs are available and present some level of toxicity. Many lignans and neolignans have been used for the development of new antileishmania drugs. The capability in vitro of the neolignan 2,3‐dihydrobenzofuran (2,3‐DBF), a commonly found constituent of propolis and other plants, to inhibit the growth of promastigote and macrophage‐internalized amastigote forms of Leishmania amazonensis was investigated. The cytotoxicity of this compound was assessed by MTT (3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5‐diphenyltetrazolium bromide) test in BALB/c murine macrophages and human erythrocyte lysis assay. The 2,3‐DBF was active against promastigote (IC₅₀=1.042 μM) and amastigote (IC₅₀=1.43 μM) forms, indicating a potent antileishmanial effect. There was no evidence of cytotoxicity to macrophages or erythrocytes at concentrations ranging from 13 to 0.5 μM, after 48 hr of exposure. The antileishmanial activity is probably mediated by the activation of macrophages, because treatment with 2,3‐DBF increases both phagocytic and lysosomal activities, as well as the nitrite (NO₂^?) levels. These results suggest that 2,3‐DBF may be a potential candidate for the development of a new promising antileishmanial drug. Further studies are needed to determine its potential in vivo effect as well as additional mechanisms underlying the antileishmanial and immunomodulatory activities.     

Activity of Extracts and Coumarins from the Leaves of Calophyllum brasiliense. on Leishmania braziliensis.

Abstract

In the current study, we evaluated the activity of extracts and (-)mammea A/BB from the leaves of Calophyllum brasiliense. Camb. (Clusiaceae), against Leishmania braziliensis.. The dichloromethane extract and the coumarin (-)mammea A/BB showed significant activity against the promastigote forms of L. braziliensis., with a 50% lethal dose (LD₅₀) at concentrations of 60 and 23.2 μ g/mL, respectively. However, the aqueous extract from the leaves and amentoflavone showed no activity against promastigote forms. For the intracellular amastigote form, the dichloromethane extract and the coumarin (-)mammea A/BB reduced by 50% the infection index of parasites in macrophages at concentrations of 22 and 29 μ g/mL, respectively. In addition, the dichloromethane extract did not show cytotoxic effects against mouse peritoneal macrophages at concentration up to 1000 μ g/mL. On the other hand, the coumarin (-)mammea A/BB showed more cytotoxicity than the dichloromethane extract. The compounds were characterized by one and two-dimensional ¹H and ¹³C NMR analyses, and LC/UV/MS was used to identify (-)mammea A/BB and amentoflavone in the dichloromethane extract. These results provide new perspectives on the development of novel drugs with leishmanicidal activities obtained from natural products.