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Bioprospecting and synthesis of strategically designed molecules have been used in the search for drugs that can be in leishmaniasis. Hydrazones (HDZ) are promising compounds with extensive biological activities. The objective of this work was to perform in silico studies of hydrazones 1-5 and to evaluate their antileishmanial, cytotoxic and macrophage immunomodulatory potential in vitro. Hydrazones were subjected to prediction and molecular docking studies. Antileishmanial protocols on promastigotes and amastigotes of Leishmania amazonensis, cytotoxicity and macrophage immunomodulatory activity were performed. Hydrazones showed a good pharmacokinetic profile and hydrazone 3 and hydrazone 5 were classified as non-carcinogenic. Hydrazone 5 obtained the best conformation with trypanothione reductase. Hydrazone 1 and hydrazone 3 obtained the best mean inhibitory concentration (IC 50 ) values for promastigotes, 4.4-61.96 μM and 8.0-58.75 μM, respectively. It also showed good activity on intramacrophagic amastigotes, with hydrazone 1 being the most active (IC 50  = 6.79 μM) with selectivity index of 56. In cytotoxicity to macrophages hydrazone 3 was the most cytotoxic (CC 50  = 256.3 ± 0,04 μM), while hydrazone 4 the least (CC 50  = 1055.9 ± 0.03 μM). It can be concluded that the hydrazones revealed important pharmacokinetic and toxicological properties, in addition to antileishmania potential in reducing infection and infectivity in parasitized macrophages., Competing Interests: Declaration of Competing Interest The authors declare that they have no conflict of interest., (Copyright © 2023. Published by Elsevier Ltd.)

Background: Chemoinformatics has several applications in the field of drug design, helping to identify new compounds against a range of ailments. Among these are Leishmaniasis, effective treatments for which are currently limited., Objective: To construct new indole 2-aminothiophene molecules using computational tools and to test their effectiveness against Leishmania amazonensis (sp.)., Methods: Based on the chemical structure of thiophene-indol hybrids, we built regression models and performed molecular docking, and used these data as bases for design of 92 new molecules with predicted pIC50 and molecular docking. Among these, six compounds were selected for the synthesis and to perform biological assays (leishmanicidal activity and cytotoxicity)., Results: The prediction models and docking allowed inference of characteristics that could have positive influences on the leishmanicidal activity of the planned compounds. Six compounds were synthesized, one-third of which showed promising antileishmanial activities, with IC50 ranging from 2.16 and 2.97 μM (against promastigote forms) and 0.9 and 1.71 μM (against amastigote forms), with selectivity indexes (SI) of 52 and 75., Conclusion: These results demonstrate the ability of Quantitative Structure-Activity Relationship (QSAR)-based rational drug design to predict molecules with promising leishmanicidal potential, and confirming the potential of thiophene-indole hybrids as potential new leishmanial agents., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

This study is a report on the anti-Leishmania activity of Morita-Baylis-Hillman (MBH) homodimers adducts against the promastigote and axenic amastigote forms of Leishmania (Leishmania) infantum and Leishmania (Leishmania) amazonensis and on the cytotoxicity of these adducts to human blood cells. Both studied homodimers, MBH 1 and MBH 2, showed activity against the promastigote forms of L. infantum and L. amazonensis, which are responsible for visceral and cutaneous leishmaniasis, respectively. Additionally, the homodimers presented biological activity against the axenic amastigote forms of these two Leishmania species. The adducts exhibited no hemolytic activity to human peripheral blood mononuclear cells or erythrocytes at the tested concentrations and achieved higher selectivity indices than amphotericin B. Evaluation of cell death by apoptosis revealed that the homodimers had better apoptosis/necrosis profiles than amphotericin B in the promastigote forms of both L. infantum and L. amazonensis. In conclusion, these Morita-Baylis-Hillman adducts had anti-Leishmania activity in an in vitro model and may thus be promising molecules in the search for new drugs to treat leishmaniasis.

Myracrodruon urundeuva (Engl.) Fr. All., commonly known as "aroeira-do-sertão", is a medicinal plant from Anacardiaceae family. In this study, the chemical composition of M. urundeuva essential oil (MuEO) was evaluated by gas chromatography-mass spectrometry (GC-MS), as well as its anti-Leishmania potential, cytotoxicity, and macrophage activation capability as possible antiprotozoal mechanism of action were assessed. Fourteen compounds were identified, which constituted 94.87% of total oil composition. The most abundant components were monoterpenes (80.35%), with β-myrcene (42.46%), α-myrcene (37.23%), and caryophyllene (4.28%) as the major constituents. The MuEO inhibited the growth of promastigotes (IC 50 205 ± 13.4 μg mL -1 ), axenic amastigotes (IC 50 104.5 ± 11.82 μg mL -1 ) and decreased percentage of macrophage infection and number of amastigotes per macrophage (IC 50 of 44.5 ± 4.37 μg⋅mL -1 ), suggesting significant anti-Leishmania activity. The cytotoxicity of MuEO was assessed by MTT test in Balb/c murine macrophages and by human erythrocytes lysis assay and low cytotoxicity for these cells was observed. The CC 50 value against macrophages were 550 ± 29.21 μg mL -1 , while cytotoxicity for erythrocytes was around 20% at the highest concentration assessed, with HC 50  > 800 μg mL -1 . While MuEO-induced anti-Leishmania activity is not mediated by increases in both lysosomal activity and nitric oxide production in macrophages, the results suggest the antiamastigote activity is associated with an immunomodulatory activity of macrophages due to an increase of phagocytic capability induced by MuEO. Thus, MuEO presented significant activity against Leishmania amazonensis, probably modulating the activation of macrophages, with low cytotoxicity to murine macrophages and human erythrocytes., (Copyright © 2017 Elsevier Inc. All rights reserved.)

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 (IC 50 =1.042 μM) and amastigote (IC 50 =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 (NO 2 - ) 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., (© 2016 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).)

Leishmaniasis represents a series of severe neglected tropical diseases caused by protozoa of the genus Leishmania and is widely distributed around the world. Here, we present the syntheses of Morita-Baylis-Hillman adducts (MBHAs) prepared from eugenol, thymol and carvacrol, and their bioevaluation against promastigotes of Leishmania amazonensis . The new MBHAs are prepared in two steps from essential oils in moderate to good yields and present IC 50 values in the range of 22.30-4.71 μM. Moreover, the selectivity index to the most potent compound is very high (SIrb > 84.92), far better than that of Glucantime ® (SIrb 1.39) and amphotericin B (SIrb = 22.34). Conformational analysis were carried out at the M062X//6-31+G(d,p) level of theory to corroborate a hypothesis about the nitroaromatic bioreduction mechanism.

Zanthoxylum rhoifolium Lam. (Rutaceae) has been traditionally used in the treatment of microbial infections and parasitic diseases. In the present study, the antileishmanial effect induced by the ethanol extract of stem barks from Z. rhoifolium (ZR-EEtOH) and its n-hexane fraction (ZR-FHEX) on infection and infectivity of murine macrophages by promastigote forms of Leishmania amazonensis were investigated. In different set of experiments, macrophages or promastigotes were pretreated with ZR-EEtOH or ZR-FHEX at non-lethal concentrations for 24 hours, and then macrophages were submitted to infection by promastigotes. Moreover, their effects on activation of macrophages, as well as on the DNA content, size and number of promastigotes by flow cytometry were also evaluated. The infection rate and the number of internalized amastigote forms were markedly decreased after pretreatment of macrophages or promastigotes when compared with non-treated cells. The increase in phagocytic capability and nitrite content was also observed. Furthermore, the decrease of DNA content, size and number of promastigotes was also observed. In conclusion, ZR-EEtOH and ZR-FHEX promoted a markedly significant antileishmanial effect and reduction of infection of macrophages, probably underlying defense mechanisms activation in macrophages. These findings reinforce the potential application of Z. rhoifolium in the treatment of leishmaniasis.

This study evaluated the effects of 2-amino-thiophene derivatives on the promastigote and amastigote forms of Leishmania (Leishmania) amazonensis and their possible mechanisms of action. Initially, we evaluated the antileishmanial activity of ten 2-amino-thiophene derivatives on promastigote and axenic amastigote forms of Leishmania amazonensis and their cytotoxicity against murine macrophages and human red blood cells. Three promising compounds were selected for studies of the cell death process using flow cytometry analysis and a DNA fragmentation assay. The effects of the compounds were assessed on intramacrophagic amastigotes, and the modulation of cytokine and NO production was investigated. All thiophene derivatives showed antileishmanial activity against promastigotes and axenic amastigotes with less toxicity for murine macrophages and human red blood cells. The best values were obtained for compounds containing a lateral indole ring. Docking studies suggested that these compounds played an important role in inhibiting trypanothione reductase (TryR) activity. The selected compounds SB-200, SB-44, and SB-83 induced apoptosis in promastigotes involving phosphatidylserine externalization and DNA fragmentation in a pattern similar to that observed for the positive control. Additionally, SB-200, SB-44, and SB-83 significantly reduced the infection index of macrophages by the parasites; for compounds SB-200 and SB-83 this reduction was associated with increased TNF-α, IL-12, and NO levels. This study demonstrated the effective and selective action of 2-amino-thiophene derivatives against L. amazonensis, resulting in apoptosis-like cell death and immunomodulation in vitro. The results suggest that they are promising compounds for the development of new leishmanicidal drugs., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

The chemical composition and biological potential of the essential oil extracted from Syzygium cumini leaves collected in Brazil were examined. GC/MS Analyses revealed a high abundance of monoterpenes (87.12%) in the oil. Eleven compounds were identified, with the major components being α-pinene (31.85%), (Z)-β-ocimene (28.98%), and (E)-β-ocimene (11.71%). To evaluate the molluscicidal effect of the oil, it was tested against Biomphalaria glabrata and the LC₅₀ obtained was 90 mg/l. The essential oil also showed significant activity against Leishmania amazonensis, with an IC50 value equal to 60 mg/l. In addition, to evaluate its toxicity towards a non-target organism, the essential oil was tested against Artemia salina and showed a LC₅₀ of 175 mg/l. Thus, the essential oil of S. cumini showed promising activity as a molluscicidal and leishmanicidal agent and might be valuable in combating neglected tropical diseases such as schistosomiasis and leishmaniasis. Further research is being conducted with regard to the purification and isolation of the most active essential-oil compounds., (Copyright © 2013 Verlag Helvetica Chimica Acta AG, Zürich.)