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BACKGROUND: Chagas disease (CD) is a neglected tropical disease caused by Trypanosoma cruzi. The current drugs used to treat these diseases have limited efficacy and produce severe side effects. 4-aminoquinoline derivatives were shown to be a promising class of inhibitors of cysteine proteases cruzain and TbrCATL. OBJECTIVES: To evaluate the trypanocidal activity of a new series of aminoquinolines as potential inhibitors of cruzain and TbrCATL. METHODS: Three aminoquinolines were synthesised and their in vitro activity was evaluated against cruzain and TbrCATL as well as against amastigotes and trypomastigotes forms of T. cruzi. In silico studies were also carried out to try to understand the experimental results. FINDINGS: Compound 5 showed promising activity against cruzain and TbrCATL, with better performance than E60, the reference drug. Compound 5 inhibited cruzain and TbrCATL at IC50 of 23 µM ±3 and 29 µM ±1, respectively, but this inhibition showed characteristics of promiscuous inhibition by colloidal aggregation. On the other hand, the compound 4 showed to be more promising activity against T. cruzi with IC50 2.57 µM ± 0.03 lower than the reference drug benznidazole 3.8 µM. MAIN CONCLUSIONS: The results of this study can guide new drug development for the treatment of trypanosomiasis.

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BACKGROUND: Despite the strides made in recent decades, the resistance observed in existing antimalarial drugs, and the intricate life cycle of the Plasmodium parasite underscore the pressing need to develop novel and effective therapeutic interventions. This article provides a comprehensive evaluation of the outcomes stemming from screening a library comprising 48 compounds (TCAMS) against Plasmodium falciparum. METHODS: This study focused on characterizing the IC50 values of compounds from the Tres Cantos Antimalarial Set (TCAMS) library via a double-labelling method of P. falciparum parasites with SYBR Green-I and MitoTracker Deep Red, which were evaluated via flow cytometry. Evaluation of the cytotoxicity of the best candidates in human embryonic kidney (HEK293) cells, chemoinformatic analysis, and exploration of the effects of the compounds on the action of serotonin and melatonin in the erythrocytic life cycle of the parasite. RESULTS: IC50 characterization confirmed that 93.75% of the compounds tested exhibited antimalarial activity at concentrations below 2 micromolar (µM), with 5 compounds showing IC50 values below 50 nM (nM) (15.21 ± 5.97 nM to 45.82 ± 5.11 nM). Furthermore, 12 compounds presented IC50 values between 50 and 100 nM (57.43 ± 12.25 nM to 100.6 ± 22.89 nM), highlighting their potent in vitro efficacy against P. falciparum. Cytotoxicity evaluation in HEK293 cells revealed that 12 from 17 compounds did not significantly reduce cell viability. Cheminformatics analysis clustered the compounds based on structural and physicochemical similarities, revealing distinct structural patterns. Exploration of hypothetical targets from the TCAMS library identified 27 compounds with potential targets, 15 specifically targeted serotonergic receptors. Subsequent serotonin and melatonin treatment experiments indicated that certain compounds could inhibit both effects on parasitaemia, suggesting a complex interaction with signaling in P. falciparum. CONCLUSIONS: This study identifies promising antimalarial candidates with low IC50 values and highlights the significance of targeting serotonin receptors in the development of potential antimalarial drugs.

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The current treatment of leishmaniasis is confronted with significant challenges, including limited efficacy, adverse effects, and parasite resistance to drugs. The search for alternative therapeutic options, including the utilisation of natural products, has demonstrated considerable promise. In this study, the antileishmanial activity of the flavonoid hesperetin against Leishmania donovani, the causative agent of visceral leishmaniasis, was reported for the first time. Hesperetin was obtained through the hydrolysis of hesperidin and subsequently subjected to chemical characterisation via Infrared and NMR spectroscopy. The antileishmanial activity and cytotoxicity against RAW 264.7 macrophages were evaluated using the MTT colorimetric assay. In order to investigate the potential mechanisms of action, in vitro acetylcholinesterase inhibition assays and molecular docking analyses were conducted. Hesperetin showed an antipromastigote effect (IC50: 62.89 µM) with no evidence of cytotoxicity (CC50: 612.8 µM), with a selectivity index (SI) of 9.74, being 5.4 times more effective than trivalent antimony. In comparison, antimony showed an IC50 of 80.16 µM, a CC50 of 145.04 µM and a SI of 1.8, indicating a limited safety margin. The compound was observed to inhibit acetylcholinesterase (IC50 of 18.44 µg/mL), present in mitochondrial and plasma membrane of the parasite. Molecular docking and dynamic simulations indicated that hesperetin inhibit sterol C-24 reductase, essential for ergosterol biosynthesis and membrane integrity of L. donovani and shows activity against N-myristoyl transferase, responsible for parasite proliferation cycle. These findings open promising avenues for the development of effective antileishmanial therapies.

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Cutaneous Leishmaniasis and Chagas disease are neglected tropical diseases that affect millions worldwide. Despite the high morbidity associated with these infections, current treatments are often highly toxic and are showing diminishing efficacy. Thus, new therapeutic options are urgently needed. In this study, bio-guided assays were conducted on the sawdust of Tabebuia chrysantha ("guayacán") to identify promising bioactive compounds. The ethanolic crude extract, five chromatography fractions, pure isoflavans sativan and vestitol, and a mixture were evaluated in vitro against Leishmania braziliensis and Trypanosoma cruzi. High leishmanicidal and trypanocidal activities were observed in the crude extract, fraction F2 (rich in sativan and vestitol), and the two pure isoflavans. Given the abundance and ease of obtaining the isoflavan mixture, its therapeutic potential was further evaluated in vivo in hamsters infected with L. braziliensis and mice infected with T. cruzi. Remarkably, topical and intraperitoneal administration of the chromatography fraction achieved a 67% clinical cure in hamsters with L. braziliensis infection and a 75% reduction in parasitemia in T. cruzi-infected mice. While the antiparasitic effects of certain flavonoids have been documented, this study is the first to demonstrate the efficacy of isoflavans in animal models for both diseases. The potential efficacy observed against T. cruzi and L. braziliensis, two pathogens with limited treatment options and a significant drawback of the available treatments, highlights the therapeutic potential of this combination of sativan and vestitol, which can be derived from timber industry waste, presenting an abundant and accessible source for further development.

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In the present study, 5-Hydroxy-2-(Oleoyloxymethyl) -4H-pyran-4-one (KMO 3), and their chelated with Cu(II) and Fe(III) ions were synthesized to explore their inhibitory activity against tyrosinase and cytotoxicity. To this end, the structures of the obtained compounds were confirmed by ATR/FT-IR, 13C and 1H-NMR, and UV-vis techniques. The results show that chelating fatty ester presents the bands at 1567m, 1511w cm-1 attributed to the coordinated carbonyl (Cu(II)←[O=C]2), and the bands at 1540m, 1519m cm-1 which were attributed to the coordinated carbonyl (Fe(III)←[O=C]3). The inhibitory effect of chelating Oleic acid 2 (inhibition 68.3% ± 4.5) showed a factor of 19 times higher than free fatty acid (3.6% ± 3.2). IC50 Anti-tyrosinase activity of the Kojic acid 1 and KMO 3 compounds were 62.8 ± 6.6 µM and 77.6 ± 4.3 µM. The IC50 and IC90 values for tyrosinase inhibitory activity for chelating fatty ester and their complexes are values > 400 µM. Finally, the assay with the series showed no hemolytic activity (EC50> 250 µg mL-1), and not cytotoxic to B16F10, ACP-02, and human dermal fibroblast cells at 100 µM and showed no hemolytic potential at the concentration of IC50 250 µM.

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Leishmaniasis, a protozoan disease affecting humans, exposes significant shortcomings in current treatments. In continuation to our previous findings on amidoxime-based antileishmanial compounds bearing a 4,5-dihydrofuran scaffold, twelve new amidoxime derivatives substituted at position 3 with an amide bearing a nitrogen heterocycle were synthesized. This series was designed to replace the sulfone and aryl group on a previously reported HIT. The synthesis of these compounds involved the following three-step pathway: manganese (III) acetate-based cyclization of a ß-ketoester, followed by amidation with LiHMDS and a final reaction with hydroxylamine. Three of them, containing either bromine, chlorine, or methyl substitutions and featuring a pyridine moiety, showed an interesting toxicity-activity relationship in vitro. They exhibited IC50 values of 15.0 µM, 16.0 µM, and 17.0 µM against the promastigote form of the parasite and IC50 values of 0.5 µM, 0.6 µM, and 0.3 µM against the intracellular amastigote form, respectively. A selectivity index (SI) greater than 300 was established between the cytotoxic concentrations (in murine macrophages) and the effective concentrations (against the intracellular form of Leishmania amazonensis). This SI is at least seventy times higher than that observed for Pentamidine and twenty-five times higher than that observed for the reference HIT, as previously reported.

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The present study aimed to evaluate the anti-staphylococcal, antibiofilm, cytotoxicity and trypanocidal activity, mechanisms of parasite death and immunomodulatory effect of CrataBL encapsulated into liposomes (CrataBL-Lipo). CrataBL-Lipo were prepared by the freeze-thaw technique and characterized. Anti-staphylococcal and antibiofilm activities of CrataBL and CrataBL-Lipo were evaluated against standard and clinical strains of Staphylococcus aureus susceptible and resistant. Thus, broth microdilution method was performed to determine the Minimum Inhibitory Concentration (MIC). Antibiofilm activity at subinhibitory concentrations was evaluated using the crystal violet staining method. Cytotoxicity of CrataBL-Lipo was verified in L929 fibroblasts and J774A.1 macrophages by determining the inhibitory concentration necessary to kill 50 % of cells (IC50). Trypanocidal activities of CrataBL-Lipo was evaluated in Trypanosoma cruzi and the efficacy was expressed as the concentration necessary to kill 50 % of parasites (EC50). The mechanisms of parasite death and immunomodulatory effect of CrataBL-Lipo were evaluated using flow cytometry analysis. CrataBL-Lipo presented Ø of 101.9 ± 1.3 nm (PDI = 0.245), ζ of +33.8 ± 1.3 mV and %EE = 80 ± 0.84 %. CrataBL-Lipo presented anti-staphylococcal activity (MIC = 0.56 mg/mL to 0.72 mg/mL). CrataBL-Lipo inhibited 45.4 %-75.6 % of biofilm formation. No cytotoxicity of CrataBL-Lipo was found (IC50 > 100 mg/L). CrataBL-Lipo presented EC50 of 1.1 mg/L, presenting autophagy, apoptosis and necrosis as death profile. In addition, CrataBL-Lipo reduced the production of IL-10 and TNF-α levels, causing an immunomodulatory effect. CrataBL-Lipo has a therapeutic potential for the treatment of staphylococcal infections and Chagas disease exhibiting a high degree of selectivity for the microorganism, and immunomodulatory properties.

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The present work reports the inhibitory effect of amides derived from gallic acid (gallamides) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) main protease (Mpro), along with cytotoxicity evaluation and molecular docking studies. In addition to gallamides, other relevant compounds were also synthesized and evaluated against Mpro, making a total of 25 compounds. Eight compounds presented solubility issues during the inhibitory assay and one showed no inhibitory activity. Compounds 3a, 3b, and 3f showed the highest enzymatic inhibition with IC50 = 0.26 ± 0.19 µM, 0.80 ± 0.38 µM, and 2.87 ± 1.17 µM, respectively. Selenogallamide 6a exhibited IC50 values of 5.42 ± 2.89 µM and a comparison with its nonselenylated congener 3c shows that the insertion of the chalcogen moiety improved the inhibitory capacity of the compound by approximately 10 times. Regarding the cellular toxicity in THP-1 and Vero cells, compounds 3e and 3g, showed moderate cytotoxicity in Vero cells, while for THP-1 both were nontoxic, with CC50 > 150 µM. Derivative 3d showed moderate cytotoxicity against both cell lines, whereas 6d was moderatly toxic to THP-1. Other compounds analyzed do not induce substantial cellular toxicity at the concentrations tested. The molecular docking results for compounds 3a, 3b, and 3f show that hydrogen bonding interactions involving the hydroxyl groups (OH) of the gallate moiety are relevant, as well as the carbonyl group.

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Fasciolosis is a food and waterborne disease caused by Fasciola spp., representing a global health burden to various hosts, including humans and other animals. This study investigates the in vitro activity of tellurium- and selenium-containing diaryl dichalcogenides: diacetal ditelluride (LQ07), diacetal diselenide (LQ62), and diacetyl diselenide (LQ68) alone and in combination with ivermectin (IVM) against eggs of Fasciola hepatica. The eggs were exposed for 12 h with each organochalcogen (OC) (0.1 - 2 mmol l-1) and IVM (0.01 - 2 mmol l-1) following an incubation of 15 days, allowing embryonation. The inhibitory concentration of 50 % (IC50) of each OC or IVM was tested with the IC10, IC30, and IC50 of IVM or each OC, respectively. LQ07, LQ62, and LQ68, as well as IVM, demonstrated a concentration-dependent ovicidal activity. The peak ovicidal activity of 99.74 % was achieved when IVM was tested at 2.0 mmol l-1. LQ62 and LQ68 demonstrated greater ovicidal activity, having an IC50 < 0.32 mmol l-1 being 6.25-fold more toxic than IVM alone. The percentage of dead eggs was significantly higher in the IVM group (early mortality), as Se-containing OCs led to the (miracidia) embryonation of the eggs with no hatching (late mortality). Blending Se-containing OCs and IVM showed an additive effect of up to 27 % against F. hepatica eggs. The present data contribute to the potential use of blending-based therapeutic strategies to combat F. hepatica infections in eradication programs worldwide. The combinations may also act against multidrug-resistant strains, reinstating drug-based parasite control.

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BACKGROUND: The current treatments for Chagas disease (CD) include benznidazole and nifurtimox, which have limited efficacy and cause numerous side effects. Triazoles are candidates for new CD treatments due to their ability to eliminate T. cruzi parasites by inhibiting ergosterol synthesis, thereby damaging the cell membranes of the parasite. METHODS: Eleven synthetic analogs of the kinase inhibitor SRPIN340 containing a triazole core (compounds 6A-6K) were screened in vitro against the Tulahuen strain transfected with ß-galactosidase, and their IC50, CC50, and selectivity indexes (SI) were calculated. Compounds with an SI > 50 were further evaluated in mice infected with the T. cruzi Y strain by rapid testing. RESULTS: Eight compounds were active in vitro with IC50 values ranging from 0.5-10.5 µg/mL. The most active compounds, 6E and 6H, had SI values of 125.2 and 69.6, respectively. These compounds also showed in vivo activity, leading to a reduction in parasitemia at doses of 10, 50, and 250 mg/kg/day. At doses of 50 and 250 mg/kg/day, parasitemia was significantly reduced compared to infected untreated animals, with no significant differences between the effects of 6E and 6H. CONCLUSIONS: This study identified two new promising compounds for CD chemotherapy and confirmed their activity against T. cruzi.

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Leishmaniasis is a disease of public health relevance that demands new therapeutic alternatives due to the toxicity of conventional treatments. In this study, 27 plants of interest to the Unified Health System (SUS) were evaluated for cytotoxicity in macrophages, leishmanicidal activity and production of nitric oxide (NO). None of the species demonstrated cytotoxicity to macrophages (CC50 >100 µg/mL). Extracts from Chenopodium ambrosioides, Equisetum arvense, Maytenus ilicifolia showed greater efficacy in inducing the death of Leishmania amazonensis amastigotes with IC50 of 68.4, 82.3, 75.7 µg/mL, respectively. The species Cynara scolymus, Punica granatum and Passiflora alata were the most effective in inducing an increase in the indirect concentration of NO (41.31, 29.30 and 28.86 µM, respectively) in cultures of macrophages infected with L. amazonensis. Furthermore, Punica granatum was also the most effective species in inducing an increase in NO in macrophages infected by Leishmania chagasi (19.90 µM). The results obtained so far support the continuation of studies, with the possibility of developing safer and more effective treatments for leishmaniasis, using natural products. The identification of plants that stimulate the production of NO in macrophages infected by Leishmania opens doors for more detailed investigations of the mechanism of action of these natural products.

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In pursuit of potential agents to treat Chagas disease and leishmaniasis, we report the design, synthesis, and identification novel naphthoquinone hydrazide-based molecular hybrids. The compounds were subjected to in vitro trypanocide and leishmanicidal activities. N'-(1,4-Dioxo-1,4-dihydronaphthalen-2-yl)-3,5-dimethoxybenzohydrazide (13) showed the best performance against Trypanosoma cruzi (IC50 1.83 µM) and Leishmania amazonensis (IC50 9.65 µM). 4-Bromo-N'-(1,4-dioxo-1,4-dihydronaphthalen-2-yl)benzohydrazide (16) exhibited leishmanicidal activity (IC50 12.16 µM). Regarding trypanocide activity, compound 13 was low cytotoxic to LLC-MK2 cells (SI = 95.28). Furthermore, through molecular modeling studies, the cysteine proteases cruzain, rhodesain and CPB2.8 were identified as the potential biological targets.

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New affordable drugs are needed for the treatment of infection with the protozoan parasite Trypanosoma cruzi responsible for the Chagas disease (CD). Only two old drugs are currently available, nifurtimox and benznidazole (Bz) but they exhibit unwanted side effects and display a weak activity in the late chronic phase of the disease. In this context, we evaluated the activity of a series of aryl-pyrazolone derivatives against T cruzi, using both bloodstream trypomastigote and intracellular amastigote forms of the parasite. The test compounds originate from a series of anticancer agents targeting the immune checkpoint ligand PD-L1 and bear an analogy with known anti-trypanosomal pyrazolones. A first group of 6 phenyl-pyrazolones was tested, revealing the activity of a single pyridyl-pyrazolone derivative. Then a second group of 8 compounds with a common pyridyl-pyrazolone core was evaluated. The in vitro testing process led to the identification of two non-cytotoxic and highly potent molecules against the intracellular form of T. cruzi, with an activity comparable to Bz. Moreover, one compound revealed an activity largely superior to that of Bz against bloodstream trypomastigotes, while being non-cytotoxic (selectivity index >1000). Unfortunately, the compound showed little activity in vivo, most likely due to its very limited plasma stability. However, the study opens novel perspectives for the design of new anti-trypanosomal products and the mechanism of action of the compounds is discussed.

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Toxoplasmosis poses a global health threat, ranging from asymptomatic cases to severe, potentially fatal manifestations, especially in immunocompromised individuals and congenital transmission. Prior research suggests that oregano essential oil (OEO) exhibits diverse biological effects, including antiparasitic activity against Toxoplasma gondii. Given concerns about current treatments, exploring new compounds is important. This study was to assess the toxicity of OEO on BeWo cells and T. gondii tachyzoites, as well as to evaluate its effectiveness in in vitro infection models and determine its direct action on free tachyzoites. OEO toxicity on BeWo cells and T. gondii tachyzoites was assessed by MTT and trypan blue methods, determining cytotoxic concentration (CC50), inhibitory concentration (IC50), and selectivity index (SI). Infection and proliferation indices were analyzed. Direct assessments of the parasite included reactive oxygen species (ROS) levels, mitochondrial membrane potential, necrosis, and apoptosis, as well as electron microscopy. Oregano oil exhibited low cytotoxicity on BeWo cells (CC50: 114.8 µg/mL ± 0.01) and reduced parasite viability (IC50 12.5 ± 0.06 µg/mL), demonstrating 9.18 times greater selectivity for parasites than BeWo cells. OEO treatment significantly decreased intracellular proliferation in infected cells by 84% after 24 h with 50 µg/mL. Mechanistic investigations revealed increased ROS levels, mitochondrial depolarization, and lipid droplet formation, linked to autophagy induction and plasma membrane permeabilization. These alterations, observed through electron microscopy, suggested a necrotic process confirmed by propidium iodide labeling. OEO treatment demonstrated anti-T. gondii action through cellular and metabolic change while maintaining low toxicity to trophoblastic cells.

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BACKGROUND: Conventional microscopic counting is a widely utilised method for evaluating the trypanocidal effects of drugs on intracellular amastigotes. This is a low-cost approach, but it is time-consuming and reliant on the expertise of the microscopist. So, there is a pressing need for developing technologies to enhance the efficiency of low-cost anti-Trypanosoma cruzi drug screening. OBJECTIVES: In our laboratory, we aimed to expedite the screening of anti-T. cruzi drugs by implementing a fluorescent method that correlates emitted fluorescence from green fluorescent protein (GFP)-expressing T. cruzi (Tc-GFP) with cellular viability. METHODS: Epimastigotes (Y strain) were transfected with the pROCKGFPNeo plasmid, resulting in robust and sustained GFP expression across epimastigotes, trypomastigotes, and intracellular amastigotes. Tc-GFP epimastigotes and intracellular amastigotes were exposed to a serial dilution of benznidazole (Bz). Cell viability was assessed through a combination of microscopic counting, MTT, and fluorimetry. FINDINGS: The fluorescence data indicated an underestimation of the activity of Bz against epimastigotes (IC50 75 µM x 14 µM). Conversely, for intracellular GFP-amastigotes, both fluorimetry and microscopy yielded identical IC50 values. Factors influencing the fluorimetry approach are discussed. MAIN CONCLUSIONS: Our proposed fluorometric assessment is effective and can serve as a viable substitute for the time-consuming microscopic counting of intracellular amastigotes.

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Trypanosoma cruzi (T. cruzi) causes Chagas, which is a neglected tropical disease (NTD). WHO estimates that 6 to 7 million people are infected worldwide. Current treatment is done with benznidazole (BZN), which is very toxic and effective only in the acute phase of the disease. In this work, we designed, synthesized, and characterized thirteen new phenoxyhydrazine-thiazole compounds and applied molecular docking and in vitro methods to investigate cell cytotoxicity, trypanocide activity, nitric oxide (NO) production, cell death, and immunomodulation. We observed a higher predicted affinity of the compounds for the squalene synthase and 14-alpha demethylase enzymes of T. cruzi. Moreover, the compounds displayed a higher predicted affinity for human TLR2 and TLR4, were mildly toxic in vitro for most mammalian cell types tested, and LIZ531 (IC50 2.8 µM) was highly toxic for epimastigotes, LIZ311 (IC50 8.6 µM) for trypomastigotes, and LIZ331 (IC50 1.9 µM) for amastigotes. We observed that LIZ311 (IC50 2.5 µM), LIZ431 (IC50 4.1 µM) and LIZ531 (IC50 5 µM) induced 200 µg/mL of NO and JM14 induced NO production in three different concentrations tested. The compound LIZ331 induced the production of TNF and IL-6. LIZ311 induced the secretion of TNF, IFNγ, IL-2, IL-4, IL-10, and IL-17, cell death by apoptosis, decreased acidic compartment formation, and induced changes in the mitochondrial membrane potential. Taken together, LIZ311 is a promising anti-T. cruzi compound is not toxic to mammalian cells and has increased antiparasitic activity and immunomodulatory properties.

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OBJECTIVE: In this study, we aimed to determine the phenolic compounds, the antibacterial activity of extract from Laurus nobilis leaves, and its possible effect on transforming growth factor-ß1 expression level in peripheral blood mononuclear cells. METHODS: The phenolic components of Laurus nobilis were identified by the high-performance liquid chromatography method. The antibacterial activity of this extract was determined by disk diffusion and broth microdilution methods. The transforming growth factor-ß1 expression was analyzed using the RT-qPCR method. RESULTS: Epicatechin was found in the highest amount and o-coumaric acid in the lowest amount. The half-maximal inhibitory concentration (IC50) was determined to be 55.17 µg/mL. The zones of inhibition and minimum inhibitory concentration for Staphylococcus aureus, Enterococcus faecalis, and Klebsiella pneumoniae were 15, 14, and 8 mm and 125, 250, and 1000 µg/mL, respectively. The change in transforming growth factor-ß1 expression levels was found to be statistically significant compared with the control groups (p<0.0001). CONCLUSION: Laurus nobilis extract was found to be effective against bacteria and altered the expression level of transforming growth factor-ß1 in peripheral blood mononuclear cells.

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Malaria continues to be a significant burden, particularly in Africa, which accounts for 95% of malaria deaths worldwide. Despite advances in malaria treatments, malaria eradication is hampered by insecticide and antimalarial drug resistance. Consequently, the need to discover new antimalarial lead compounds remains urgent. To help address this need, we evaluated the antiplasmodial activity of twenty-two amides and thioamides with pyridine cores and their non-pyridine analogues. Twelve of these compounds showed in vitro anti-proliferative activity against the intraerythrocytic stage of Plasmodium falciparum, the most virulent species of Plasmodium infecting humans. Thiopicolinamide 13i was found to possess submicromolar activity (IC50 = 142 nM) and was >88-fold less active against a human cell line. The compound was equally effective against chloroquine-sensitive and -resistant parasites and did not inhibit ß-hematin formation, pH regulation or PfATP4. Compound 13i may therefore possess a novel mechanism of action.

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INTRODUCTION: Leishmaniasis is a neglected disease with high prevalence and incidence in tropical and subtropical areas. Existing drugs are limited due to cost, toxicity, declining efficacy and unavailability in endemic places. Drug repurposing has established as an efficient way for the discovery of drugs for a variety of diseases. PURPOSE: The objective of the present work was testing the antileishmanial activity of thioridazine, an antipsychotic agent with demonstrated effect against other intracellular pathogens. METHODS: The cytotoxicity for mouse peritoneal macrophages as well as the activity against Leishmania amazonensis, Leishmania mexicana and Leishmania major promastigotes and intracellular amastigotes, as well as in a mouse model of cutaneous leishmaniasis, were assessed. RESULTS: Thioridazine inhibited the in vitro proliferation of promastigotes (50% inhibitory concentration-IC50-values in the range of 0.73 µM to 3.8 µM against L. amazonensis, L. mexicana and L. major) and intracellular amastigotes (IC50 values of 1.27 µM to 4.4 µM for the same species). In contrast, in mouse peritoneal macrophages, the 50% cytotoxic concentration was 24.0 ± 1.89 µM. Thioridazine inhibited the growth of cutaneous lesions and reduced the number of parasites in the infected tissue of mice. The dose of thioridazine that inhibited lesion development by 50% compared to controls was 23.3 ± 3.1 mg/kg and in terms of parasite load, it was 11.1 ± 0.97 mg/kg. CONCLUSIONS: Thioridazine was effective against the promastigote and intracellular amastigote stages of three Leishmania species and in a mouse model of cutaneous leishmaniasis, supporting the potential repurposing of this drug as an antileishmanial agent.

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Annona muricata Linn. (Annonaceae) is a tropical plant with multiple beneficial health effects including anticancer properties. In breast cancer patients, overexpression of the HER2 oncoprotein corresponds to a poor prognosis, thus the main purpose of this study was to evaluate the cytotoxicity of ethanolic extracts from dried and fresh leaf of A. muricata on HER2+ breast cancer cells. MTT assays were performed and IC50 determined in HCC1954 (HER2+) cells, as well as in MCF7 (HER-) and peripheral blood mononuclear cells (PBMC) used as controls. Total polyphenol content evaluation and phytochemical screening were also performed. The cytotoxic effect of A. muricata extracts (125-1000 µg/mL) was dose-dependent and cell-type specific. The extracts exhibited higher cytotoxicity against HCC1954 than MCF7 cells, but weak toxicity against PBMC. This is the first report of the cytotoxic effect of A. muricata on HCC1954 cells, highlighting its potential for treating anti-estrogen-resistant breast cancers and low toxicity against PBMC.

Annona muricata Linn. (Annonaceae) es una planta tropical con múltiples efectos benéficos en la salud incluyendo propiedades antitumorales. En pacientes con cáncer de mama la sobreexpresión del oncogen HER2 corresponde a un mal pronóstico, por lo que el objetivo principal de este estudio fue evaluar la citotoxicidad de extractos etanólicos de hojas secas y frescas de A. muricata en células tumorales de mama HER2+. Se aplicaron pruebas de MTT y se determinaron IC50en células HCC1954 (HER2+); se utilizaron células MCF7 (HER-) y células mononucleares de sangre periférica (PBMC) como control. Se valoró también el contenido en polifenoles totales, y se realizó un tamizaje fitoquímico. El efecto citotóxico de los extractos de A. muricata (125-1000 µg/mL) fue dosis-dependiente y específico para cada tipo celular. Los extractos presentaron mayor actividad citotóxica contra HCC1954 en comparación con MCF7 y baja toxicidad contra PBMC. Este es el primer reporte del efecto citotóxico de A. muricata en HCC1954 y destaca su potencial terapéutico para tratamiento de cáncer de mama resistentes a antiestrógeno y baja citotoxicidad contra PBMC.