Synthesis and Evaluation of (Bis)benzyltetrahydroisoquinoline Alkaloids as Antiparasitic Agents.

Visceral leishmaniasis and Chagas disease are neglected tropical diseases (NTDs) that severely impact the developing world. With current therapies suffering from poor efficacy and safety profiles as well as emerging resistance, new drug leads are direly needed. In this work, 26 alkaloids (9 natural and 17 synthetic) belonging to the benzyltetrahydroisoquinoline (BI) family were evaluated against both the pro/trypomastigote and amastigote forms of the parasites Leishmania infantum and Trypanosoma cruzi, the causative agents of these diseases. These alkaloids were synthesized via an efficient and modular enantioselective approach based on Bischler-Napieralski cyclization/Noyori asymmetric transfer hydrogenation to build the tetrahydroisoquinoline core. The bis-benzyltetrahydroisoquinoline (BBI) alkaloids were prepared using an Ullmann coupling of two BI units to form the biaryl ether linkage, which enabled a comprehensive survey of the influence of BI stereochemistry on bioactivity. Preliminary studies into the mechanism of action against Leishmania mexicana demonstrate that these compounds interfere with the cell cycle, potentially through inhibition of kinetoplast division, which may offer opportunities to identify a new target/mechanism of action. Three of the synthesized alkaloids showed promising druglike potential, meeting the Drugs for Neglected Disease initiative (DNDi) criteria for a hit against Chagas disease.

Synthesis and evaluation of (Bis)benzyltetrahydroisoquinoline alkaloids as antiparasitic agents

Visceral leishmaniasis and Chagas disease are neglected tropical diseases (NTDs) that severely impact the developing world. With current therapies suffering from poor efficacy and safety profiles as well as emerging resistance, new drug leads are direly needed. In this work, 26 alkaloids (9 natural and 17 synthetic) belonging to the benzyltetrahydroisoquinoline (BI) family were evaluated against both the pro/trypomastigote and amastigote forms of the parasites Leishmania infantum and Trypanosoma cruzi, the causative agents of these diseases. These alkaloids were synthesized via an efficient and modular enantioselective approach based on Bischler-Napieralski cyclization/Noyori asymmetric transfer hydrogenation to build the tetrahydroisoquinoline core. The bis-benzyltetrahydroisoquinoline (BBI) alkaloids were prepared using an Ullmann coupling of two BI units to form the biaryl ether linkage, which enabled a comprehensive survey of the influence of BI stereochemistry on bioactivity. Preliminary studies into the mechanism of action against Leishmania mexicana demonstrate that these compounds interfere with the cell cycle, potentially through inhibition of kinetoplast division, which may offer opportunities to identify a new target/mechanism of action. Three of the synthesized alkaloids showed promising druglike potential, meeting the Drugs for Neglected Disease initiative (DNDi) criteria for a hit against Chagas disease.

Andrographolide: A Diterpenoid from Cymbopogon schoenanthus Identified as a New Hit Compound against Trypanosoma cruzi Using Machine Learning and Experimental Approaches.

American Trypanosomiasis, also known as Chagas disease, is caused by the protozoan Trypanosoma cruzi and exhibits limited options for treatment. Natural products offer various structurally complex metabolites with biological activities, including those with anti-T. cruzi potential. The discovery and development of prototypes based on natural products frequently display multiple phases that could be facilitated by machine learning techniques to provide a fast and efficient method for selecting new hit candidates. Using Random Forest and k-Nearest Neighbors, two models were constructed to predict the biological activity of natural products from plants against intracellular amastigotes of T. cruzi. The diterpenoid andrographolide was identified from a virtual screening as a promising hit compound. Hereafter, it was isolated from Cymbopogon schoenanthus and chemically characterized by spectral data analysis. Andrographolide was evaluated against trypomastigote and amastigote forms of T. cruzi, showing IC50 values of 29.4 and 2.9 µM, respectively, while the standard drug benznidazole displayed IC50 values of 17.7 and 5.0 µM, respectively. Additionally, the isolated compound exhibited a reduced cytotoxicity (CC50 = 92.8 µM) against mammalian cells and afforded a selectivity index (SI) of 32, similar to that of benznidazole (SI = 39). From the in silico analyses, we can conclude that andrographolide fulfills many requirements implemented by DNDi to be a hit compound. Therefore, this work successfully obtained machine learning models capable of predicting the activity of compounds against intracellular forms of T. cruzi.

Biological activity and structure-activity relationship of dehydrodieugenol B analogues against visceral leishmaniasis.

Visceral leishmaniasis is a neglected protozoan disease with high mortality. Existing treatments exhibit a number of limitations, resulting in a significant challenge for public health, especially in developing countries in which the disease is endemic. With a limited pipeline of potential drugs in clinical trials, natural products could offer an attractive source of new pharmaceutical prototypes, not least due to their high chemodiversity. In the present work, a study of anti-L. (L.) infantum potential was carried out for a series of 39 synthetic compounds based on the core scaffold of the neolignan dehydrodieugenol B. Of these, 14 compounds exhibited activity against intracellular amastigotes, with 50% inhibitory concentration (IC50) values between 3.0 and 32.7 µM. A structure-activity relationship (SAR) analysis demonstrated a requirement for polar functionalities to improve activity. Lacking mammalian cytotoxicity and presenting the highest potency against the clinically relevant form of the parasite, compound 24 emerged as the most promising, fulfilling the hit criteria for visceral leishmaniasis defined by the Drugs for Neglected Diseases initiative (DNDi). This study emphasizes the potential of dehydrodieugenol B analogues as new candidates for the treatment of visceral leishmaniasis and suggests 24 to be a suitable compound for future optimization, including mechanism of action and pharmacokinetic studies.

Piperazine amides with desirable solubility, physicochemical and drug-like properties: Synthesis and evaluation of the anti-Trypanosoma cruzi activity.

The absence of effective chronic treatment, expansion to non-endemic countries and the significant burden in public health have stimulated the search for novel therapeutic options to treat Chagas disease, a protozoan disease caused by Trypanosoma cruzi. Despite current efforts, no new drug candidates were approved in clinical trials in the past five decades. Considering this, our group has focused on the expansion of a series (LINS03) with low micromolar activity against amastigotes, considering the optimization of pharmacokinetic properties through increasing drug-likeness and solubility. In this work, we report a new set of 13 compounds with modifications in both the arylpiperazine and the aromatic region linked by an amide group. Five analogues showed activity against intracellular amastigotes (IC50 17.8 to 35.9 µM) and no relevant cytotoxicity to mammalian cells (CC50 > 200 µM). Principal component analysis (PCA) was performed to identify structural features associated to improved activity. The data revealed that polarity, hydrogen bonding ability and flexibility were key properties that influenced the antiparasitic activity. In silico drug-likeness assessments indicated that compounds with the 4-methoxycinammyl (especially compound 2b) had the most prominent balance between properties and activity in the series, as confirmed by SAR analysis.

Synthetic Analogues of Gibbilimbol B Induce Bioenergetic Damage and Calcium Imbalance in Trypanosoma cruzi.

Chagas disease is an endemic tropical disease caused by the protozoan Trypanosoma cruzi, which affects around 7 million people worldwide, mostly in development countries. The treatment relies on only two available drugs, with severe adverse effects and a limited efficacy. Therefore, the search for new therapies is a legitimate need. Within this context, our group reported the anti-Trypanosoma cruzi activity of gibbilimbol B, a natural alkylphenol isolated from the plant Piper malacophyllum. Two synthetic derivatives, LINS03018 (1) and LINS03024 (2), demonstrated a higher antiparasitic potency and were selected for mechanism of action investigations. Our studies revealed no alterations in the plasma membrane potential, but a rapid alkalinization of the acidocalcisomes. Nevertheless, compound 1 exhibit a pronounced effect in the bioenergetics metabolism, with a mitochondrial impairment and consequent decrease in ATP and reactive oxygen species (ROS) levels. Compound 2 only depolarized the mitochondrial membrane potential, with no interferences in the respiratory chain. Additionally, no macrophages response of nitric oxide (NO) was observed in both compounds. Noteworthy, simple structure modifications in these derivatives induced significant differences in their lethal effects. Thus, this work reinforces the importance of the mechanism of action investigations at the early phases of drug discovery and support further developments of the series.

Andrographolide: a diterpenoid from Cymbopogon schoenanthus identified as a new hit compound against Trypanosoma cruzi using machine learning and experimental approaches

American Trypanosomiasis, also known as Chagas disease, is caused by the protozoan Trypanosoma cruzi and exhibits limited options for treatment. Natural products offer various structurally complex metabolites with biological activities, including those with anti-T. cruzi potential. The discovery and development of prototypes based on natural products frequently display multiple phases that could be facilitated by machine learning techniques to provide a fast and efficient method for selecting new hit candidates. Using Random Forest and k-Nearest Neighbors, two models were constructed to predict the biological activity of natural products from plants against intracellular amastigotes of T. cruzi. The diterpenoid andrographolide was identified from a virtual screening as a promising hit compound. Hereafter, it was isolated from Cymbopogon schoenanthus and chemically characterized by spectral data analysis. Andrographolide was evaluated against trypomastigote and amastigote forms of T. cruzi, showing IC50 values of 29.4 and 2.9 μM, respectively, while the standard drug benznidazole displayed IC50 values of 17.7 and 5.0 μM, respectively. Additionally, the isolated compound exhibited a reduced cytotoxicity (CC50 = 92.8 μM) against mammalian cells and afforded a selectivity index (SI) of 32, similar to that of benznidazole (SI = 39). From the in silico analyses, we can conclude that andrographolide fulfills many requirements implemented by DNDi to be a hit compound. Therefore, this work successfully obtained machine learning models capable of predicting the activity of compounds against intracellular forms of T. cruzi.

A new reduced chalcone-derivative affects the membrane permeability and electric potential of multidrug-resistant Enterococcusfaecalis.

The emergence and spread of multidrug-resistant (MDR) enterococci and other Gram-positive bacteria represents a severe problem due to the lack of effective therapeutic alternatives. Natural products have long been an important source of new antibacterial scaffolds and can play a key role in the current antibiotic crisis. Enterococci are predominantly non-pathogenic gastrointestinal commensal bacteria, but among them, Enterococcus faecalis and Enterococcus faecium represent the species that account for most clinically relevant infections. The emergence of MDR enterococci has reduced the available antibiotic treatment options and highlights the need to develop new antimicrobial compounds. In the search for new hit compounds against MDR Enterococcus spp., natural-derived compounds represent inspiring scaffolds for drug design studies. In this work, the antimicrobial activity of a fully synthetic chalcone derivative (r4MB) was determined on a clinical panel of 34 MDR Gram-positive bacteria, mostly constituted by E. faecalis and E. faecium, along with Staphylococcus spp., amongst others. Compound r4MB showed activity against 100% of the tested strains, with the minimum inhibitory concentration (MIC) in the range of 5-20 µM. The lethal action of the compound was evaluated using different fluorescent-based assays. The compound showed a time-dependent permeabilisation of the membrane of a vancomycin-resistant E. faecalis, detected by the fluorescent probe SYTOX Green, and digital fluorescent microscopy corroborated the spectrofluorimetric analysis within 6 min of incubation. Flow cytometry analysis of the membrane electric potential demonstrated a significant depolarization, confirming the target of the compound towards the bacterial membrane. No cytotoxic haemolysis was observed with mammalian erythrocytes, and a 99% cytotoxic concentration of 118 µM on NCTC cells demonstrated a promising antimicrobial selectivity. In silico studies using SwissADME and ADMETLabs servers suggest that compound r4MB displayed adequate ADME properties, with no alerts for pan-assay interference compounds (PAINS). Future hit-to-lead optimization of this chalcone derivative can contribute to developing a more potent derivative against infections caused by MDR enterococci.

Mitochondrial Imbalance of Trypanosoma cruzi Induced by the Marine Alkaloid 6-Bromo-2'-de-N-Methylaplysinopsin.

Chagas disease, caused by Trypanosoma cruzi, affects seven million people worldwide and lacks effective treatments. Using bioactivity-guided fractionation, NMR, and electrospray ionization-high resolution mass spectrometry (ESI-HRMS) spectral analysis, the indole alkaloid 6-bromo-2'-de-N-methylaplysinopsin (BMA) was isolated and chemically characterized from the marine coral Tubastraea tagusensis. BMA was tested against trypomastigotes and intracellular amastigotes of T. cruzi, resulting in IC50 values of 62 and 5.7 µM, respectively, with no mammalian cytotoxicity. The mechanism of action studies showed that BMA induced no alterations in the plasma membrane permeability but caused depolarization of the mitochondrial membrane potential, reducing ATP levels. Intracellular calcium levels were also reduced after the treatment, which was associated with pH alteration of acidocalcisomes. Using matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF)/MS analysis, alterations of mass spectral signals were observed after treatment with BMA, suggesting a different mechanism from benznidazole. In silico pharmacokinetic-pharmacodynamic (PKPD) parameters suggested a drug-likeness property, supporting the promising usefulness of this compound as a new hit for optimizations.

Corrigendum: (-)-T-Cadinol, a Sesquiterpene Isolated From Casearia sylvestris (Salicaceae)-Displayed In Vitro Activity and Causes Hyperpolarization of the Membrane Potential of Trypanosoma cruzi.

[This corrects the article DOI: 10.3389/fphar.2021.734127.].

Optimization of physicochemical properties is a strategy to improve drug-likeness associated with activity: Novel active and selective compounds against Trypanosoma cruzi.

Trypanosoma cruzi is the causing agent of Chagas disease, a parasitic infection without efficient treatment for chronic patients. Despite the efforts, no new drugs have been approved for this disease in the last 60 years. Molecular modifications based on a natural product led to the development of a series of compounds (LINS03 series) with promising antitrypanosomal activity, however previous chemometric analysis revealed a significant impact of excessive lipophilicity and low aqueous solubility on potency of amine and amide derivatives. Therefore, this work reports different modifications in the core structure to achieve adequate balance of the physicochemical properties along with biological activity. A set of 34 analogues were designed considering predicted properties related to lipophilicity/hydrosolubility and synthesized to assess their activity and selective toxicity towards the parasite. Results showed that this strategy contributed to improve the drug-likeness of the series while considerable impacts on potency were observed. The rational analysis of the obtained data led to the identification of seven active piperazine amides (28-34, IC50 8.7 to 35.3 µM against intracellular amastigotes), devoid of significant cytotoxicity to mammalian cells. The addition of water-solubilizing groups and privileged substructures such as piperazines improved the physicochemical properties and overall drug-likeness of these compounds, increased potency and maintained selectivity towards the parasite. The obtained results brought important structure-activity relationship (SAR) data and new lead structures for further modifications were identified to achieve improved antitrypanosoma compounds.

Evaluation of antileishmanial potential of the antidepressant escitalopram in Leishmania infantum.

Neglected tropical diseases (NTDs) such as visceral leishmaniasis (VL) present a limited and toxic therapeutic arsenal, and drug repositioning represents a safe and cost-effective approach. In this work, we investigated the antileishmanial potential and the mechanism of lethal action of the antidepressant escitalopram. The efficacy of escitalopram was determined ex-vivo using the intracellular Leishmania (L.) infantum amastigote model and the mammalian cytotoxicity was determined by the colorimetric MTT assay. The cellular and molecular alterations induced by the drug were investigated using spectrofluorimetry, a luminescence assay and flow cytometry. Our data revealed that escitalopram was active and selective against L. infantum parasites, with an IC50 value of 25 µM and a 50% cytotoxic concentration (CC50) of 184 µM. By using the fluorescent probes SYTOX® Green and DiSBAC2(3), the drug showed no alterations in the plasma membrane permeability nor in the electric potential of the membrane (∆ψp); however, after a short-time incubation, the drug caused a dose-dependent up-regulation of the calcium levels, leading to the depolarization of the mitochondrial membrane potential (∆ψm) and a reduction of the ATP levels. No up-regulation of reactive oxygen (ROS) was observed. In the cell cycle analysis, escitalopram induced a dose-dependent increase of the parasites at the sub G0/G1 stage, representing fragmented DNA. Escitalopram presented a selective antileishmanial activity, with disruption of single mitochondrion and interference in the cell cycle. Approved drugs such as escitalopram may represent a promising approach for NTDs and can be considered in future animal efficacy studies.

(-)-T-Cadinol-a Sesquiterpene Isolated From Casearia sylvestris (Salicaceae)-Displayed In Vitro Activity and Causes Hyperpolarization of the Membrane Potential of Trypanosoma cruzi.

Chagas disease is caused by the protozoan parasite Trypanosoma cruzi and affects 6-8 million people worldwide, mainly from developing countries. The treatment is limited to two approved nitro-derivatives, nifurtimox and benznidazole, with several side effects and reduced efficacy. Casearia sylvestris has been used in folk medicine as an antiseptic and cicatrizing in skin diseases. In the present work, the hexane phase from the MeOH extract from the leaves of Casearia sylvestris afforded a fraction composed by the sesquiterpene T-cadinol, which was chemically characterized by NMR and HRMS. The activity of T-cadinol was evaluated against T. cruzi, and IC50 values of 18 (trypomastigotes) and 15 (amastigotes) µM were established. The relation between the mammalian toxicity and the antiparasitic activity resulted in a selectivity index >12. Based on this promising activity, the mechanism of action was investigated by different approaches using fluorescent-based techniques such as plasma membrane permeability, plasma membrane electric potential, mitochondrial membrane electric potential, reactive oxygen species, and the intracellular calcium (Ca2+) levels. The obtained results demonstrated that T-cadinol affected neither the parasite plasma membrane nor the electric potential of the membrane. Nevertheless, this compound induced a mitochondrial impairment, resulting in a hyperpolarization of the membrane potential, with decreased levels of reactive oxygen species. No alterations in Ca2+ levels were observed, suggesting that T-cadinol may affect the single mitochondria of the parasite. This is the first report about the occurrence of T-cadinol in C. sylvestris, and our data suggest this sesquiterpene as an interesting hit compound for future optimizations in drug discovery studies for Chagas disease.

γ-Lactones from Persea americana and Persea fulva - in Vitro and in Silico Evaluation of Trypanosoma cruzi Activity.

In the present study, five known γ-lactones (majoranolide B - 1, majorenolide - 2, majorynolide - 3, lincomolide D - 4, and isolinderanolide E - 5), as well as a new one (perseanolide - 6), were isolated from Persea fulva and P. americana. All isolated compounds exhibited potential activity against trypomastigote forms of Trypanosoma cruzi, whereas compounds 2 (EC50 of 4.8 µM) and 6 (EC50 of 3.6 µM) displayed superior activity than the positive control benznidazole (EC50 of 16.4 µM), with selectivity index (SI) values of 17.8 and >55.6, respectively (benznidazole, SI>12.2). Molecular docking studies were performed for 1-6 against six T. cruzi molecular targets. Using this approach, we observed that, even though perseanolide (6) showed favorable docking to several studied targets, the results were especially promising for hypoxanthine phosphoribosyl transferase (PDB 1TC1). As PDB 1TC1 is associated to the transference of a monophosphorylated ribose from phosphoribosylpyrophosphate (PRPP) in the ribonucleotide synthesis pathway, this interaction may affect the survival of T. cruzi in mammalian cells. The data herein also indicate that possible intermolecular interactions between 6 and PDB 1TC1 derive from (i) hydrogen bonds in the α,ß-unsaturated-γ-lactone unity and (ii) hydrophobic interactions in the long-chain alkyl group. Based on our results, perseanolide (6), reported for the first time in this work, can auspiciously contribute to future works regarding new trypanocidal agents.

Aporphine Alkaloids from Ocotea puberula with Anti-Trypanosoma Cruzi Potential - Activity of Dicentrine-ß-N-Oxide in the Plasma Membrane Electric Potentials.

One new aporphine, dicentrine-ß-N-oxide (1), together with five related known alkaloids dehydrodicentrine (2), predicentrine (3), N-methyllaurotetanine (4), cassythicine (5), and dicentrine (6) were isolated from the leaves of Ocotea puberula (Lauraceae). Antiprotozoal activity of the isolated compounds was evaluated in vitro against trypomastigote forms of Trypanosoma cruzi. Among the tested compounds, alkaloid 1 exhibited higher potential with EC50 value of 18.2 µM and reduced toxicity against NCTC cells (CC50 >200 µM - SI>11.0), similar to positive control benznidazole (EC50 of 17.7 µM and SI=10.7). Considering the promising results of dicentrine-ß-N-oxide (1) against trypomastigotes, the mechanism of parasite death caused by this alkaloid was investigated. As observed, this compound reached the plasma membrane electric potential directly after 2 h of incubation and triggered mitochondrial depolarization, which probably leads to trypomastigote death. Therefore, dicentrine-ß-N-oxide (1), reported for the first time in this work, can contribute to future works for the development of new trypanocidal agents.

Synthesis and Structure-Activity Relationship of Dehydrodieugenol B Neolignans against Trypanosoma cruzi.

Trypanosoma cruzi is the etiologic agent of Chagas disease, which affects over seven million people, especially in developing countries. Undesirable side effects are frequently associated with current therapies, which are typically ineffective in the treatment of all stages of the disease. Here, we report the first synthesis of the neolignan dehydrodieugenol B, a natural product recently shown to exhibit activity against T. cruzi. Using this strategy, a series of synthetic analogues were prepared to explore structure-activity relationships. The in vitro antiparasitic activities of these analogues revealed a wide tolerance of modifications and substituent deletions, with maintained or improved bioactivities against the amastigote forms of the parasite (50% inhibitory concentration (IC50) of 4-63 µM) and no mammalian toxicity (50% cytotoxic concentration (CC50) of >200 µM). Five of these analogues meet the Drugs for Neglected Disease Initiative (DNDi) "hit criteria" for Chagas disease. This work has enabled the identification of key structural features of the natural product and sites where scaffold modification is tolerated.

A semi-synthetic neolignan derivative from dihydrodieugenol B selectively affects the bioenergetic system of Leishmania infantum and inhibits cell division.

Leishmaniasis is a neglected disease that affects more than 12 million people, with a limited therapy. Plant-derived natural products represent a useful source of anti-protozoan prototypes. In this work, four derivatives were prepared from neolignans isolated from the Brazilian plant Nectandra leucantha, and their effects against intracellular amastigotes of Leishmania (L.) infantum evaluated in vitro. IC50 values between 6 and 35 µM were observed and in silico predictions suggested good oral bioavailability, no PAINS similarities, and ADMET risks typical of lipophilic compounds. The most selective (SI > 32) compound was chosen for lethal action and immunomodulatory studies. This compound caused a transient depolarization of the plasma membrane potential and induced an imbalance of intracellular Ca2+, possibly resulting in a mitochondrial impairment and leading to a strong depolarization of the membrane potential and decrease of ATP levels. The derivative also interfered with the cell cycle of Leishmania, inducing a programmed cell death-like mechanism and affecting DNA replication. Further immunomodulatory studies demonstrated that the compound eliminates amastigotes via an independent activation of the host cell, with decrease levels of IL-10, TNF and MCP-1. Additionally, this derivative caused no hemolytic effects in murine erythrocytes and could be considered promising for future lead studies.

Butenolides from Nectandra oppositifolia (Lauraceae) displayed anti-Trypanosoma cruzi activity via deregulation of mitochondria.

BACKGROUND: From a previous screening of Brazilian biodiversity for antitrypanosomal activity, the n-hexane extract from twigs of Nectandra oppositifolia (Lauraceae) demonstrated in vitro activity against Trypanosoma cruzi. PURPOSE: To perform the isolation and chemical characterization of bioactive compounds from n-hexane extract from twigs of N. oppositifolia and evaluate their therapeutical potential as well as to elucidate their mechanism of action against T. cruzi. METHODS/STUDY DESIGN: Bioactivity-guided fractionation of the n-hexane extract from twigs of N. oppositifolia afforded three related butenolides: isolinderanolide D (1), isolinderanolide E (2) and secosubamolide A (3). These compounds were evaluated in vitro against T. cruzi (trypomastigote and amastigote forms) and against NCTC (L929) cells for mammalian cytotoxicity. Additionally, phenotypic analyzes of compounds-treated parasites were performed: alterations in the plasma membrane permeability, plasma membrane electric potential (ΔΨp), mitochondrial membrane potential (ΔΨm) and induction of ROS. RESULTS: Compounds 1-3 were effective against T. cruzi, with IC50 values of 12.9, 29.9 and 12.5 µM for trypomastigotes and 25.3, 10.1 and 12.3 µM for intracellular amastigotes. Furthermore, it was observed alteration in the mitochondrial membrane potential (ΔΨm) of parasites treated with butenolides 1-3. These compounds caused no alteration to the parasite plasma membrane, and the deregulation of the mitochondria might be an early event to cell death. In addition, in silico studies showed that all butenolides were predicted to be non-mutagenic, non-carcinogenic, non hERG blockers, with acceptable human intestinal absorption, low inhibitory promiscuity with the main five CYP isoforms, and with high metabolic stability. Otherwise, tested butenolides showed unfavorable blood-brain barrier penetration (BBB+). CONCLUSION: Our results demonstrated the anti-T. cruzi effects of compounds 1-3 isolated from N. oppositifolia and indicated that the lethal effect of these compounds in trypomastigotes of T. cruzi could be associated to the alteration in the mitochondrial membrane potential (ΔΨm).

A semi-synthetic neolignan derivative from dihydrodieugenol B selectively affects the bioenergetic system of Leishmania infantum and inhibits cell division / A semi-synthetic neolignan derivative from dihydrodieugenol B selectively affects the bioenergetic system of Leishmania infantum and inhibits cell division

Leishmaniasis is a neglected disease that affects more than 12 million people, with a limited therapy. plant-derived natural products represent a useful source of anti-protozoan prototypes. In this work, four derivatives were prepared from neolignans isolated from the Brazilian plant Nectandra leucantha, and their effects against intracellular amastigotes of Leishmania (L.) infantum evaluated in vitro. IC50 values between 6 and 35 µM were observed and in silico predictions suggested good oral bioavailability, no pAINs similarities, and ADMet risks typical of lipophilic compounds. the most selective (sI > 32) compound was chosen for lethal action and immunomodulatory studies. this compound caused a transient depolarization of the plasma membrane potential and induced an imbalance of intracellular Ca2+, possibly resulting in a mitochondrial impairment and leading to a strong depolarization of the membrane potential and decrease of ATP levels. The derivative also interfered with the cell cycle of Leishmania, inducing a programmed cell death-like mechanism and affecting DNA replication. Further immunomodulatory studies demonstrated that the compound eliminates amastigotes via an independent activation of the host cell, with decrease levels of IL-10, TNF and MCP-1. Additionally, this derivative caused no hemolytic effects in murine erythrocytes and could be considered promising for future lead studies.