Synthesis of 3-aryl-4-(N-aryl)aminocoumarins via photoredox arylation and the evaluation of their biological activity.

A new series of 3-aryl-4-(N-aryl)aminocoumarins was synthesized in two steps starting from the natural product 4-hydroxycoumarin using the photoredox catalysis for the key step. These conditions reactions allowed to make CC bonds is up to 95% yields in mild conditions, easy operation, in an environmentally benign way, and are compatible with several patterns of substitution. The biological activity of the new compounds was tested in vitro against MCF-7, MDA-MB-231, and CCD-1072Sk cancer cell lines, as soon as to promastigotes and intracellular amastigotes of Leishmania amazonensis. Compounds 17d, 17s and 17x showed activity against promastigote forms (IC50 = 5.96 ± 3.210, 9.05 ± 2.855 and 5.65 ± 2.078 µM respectively), and compound 17x presented the best activity against L. amazonensis amastigote intracellular form (IC50 = 9.6 ± 1.148 µM), no BALB/c peritoneal macrophage cytotoxicity at assayed concentrations (CC50 > 600 µM), and high selectivity to parasites over the mammalian cells (Selectivity Index > 62.2). There was no expressive activity for the cancer cell lines. Single crystal X-ray diffraction analysis was employed for structural elucidation of compounds 17a and 17s. In silico analyses of physicochemical, pharmacokinetic, and toxicological properties suggest that compound 17x is a potential candidate for anti-leishmaniasis drugs.

ATRvD1 Attenuates Renal Tubulointerstitial Injury Induced by Albumin Overload in Sepsis-Surviving Mice.

Novel strategies for the prevention and treatment of sepsis-associated acute kidney injury and its long-term outcomes have been required and remain a challenge in critical care medicine. Therapeutic strategies using lipid mediators, such as aspirin-triggered resolvin D1 (ATRvD1), can contribute to the resolution of acute and chronic inflammation. In this study, we examined the potential effect of ATRvD1 on long-term kidney dysfunction after severe sepsis. Fifteen days after cecal ligation and puncture (CLP), sepsis-surviving BALB/c mice were subjected to a tubulointerstitial injury through intraperitoneal injections of bovine serum albumin (BSA) for 7 days, called the subclinical acute kidney injury (subAKI) animal model. ATRvD1 treatment was performed right before BSA injections. On day 22 after CLP, the urinary protein/creatinine ratio (UPC), histologic parameters, fibrosis, cellular infiltration, apoptosis, inflammatory markers levels, and mRNA expression were determined. ATRvD1 treatment mitigated tubulointerstitial injury by reducing proteinuria excretion, the UPC ratio, the glomerular cell number, and extracellular matrix deposition. Pro-fibrotic markers, such as transforming growth factor ß (TGFß), type 3 collagen, and metalloproteinase (MMP)-3 and -9 were reduced after ATRvD1 administration. Post-septic mice treated with ATRvD1 were protected from the recruitment of IBA1+ cells. The interleukin-1ß (IL-1ß) levels were increased in the subAKI animal model, being attenuated by ATRvD1. Tumor necrosis factor-α (TNF-α), IL-10, and IL-4 mRNA expression were increased in the kidney of BSA-challenged post-septic mice, and it was also reduced after ATRvD1. These results suggest that ATRvD1 protects the kidney against a second insult such as BSA-induced tubulointerstitial injury and fibrosis by suppressing inflammatory and pro-fibrotic mediators in renal dysfunction after sepsis.

Antiprotozoal and Antibacterial Activity of Ravenelin, a Xanthone Isolated from the Endophytic Fungus Exserohilum rostratum.

The natural compound ravenelin was isolated from the biomass extracts of Exserohilum rostratum fungus, and its antimicrobial, antiplasmodial, and trypanocidal activities were evaluated. Ravenelin was isolated by column chromatography and HPLC and identified by NMR and MS. The susceptibility of Gram-positive and Gram-negative bacteria strains to ravenelin was determined by microbroth dilution assay. Cytotoxicity was evaluated in hepatocarcinoma cells (HepG2) and BALB/c peritoneal macrophages by using MTT. SYBR Green I-based assay was used in the asexual stages of Plasmodium falciparum. Trypanocidal activity was tested against the epimastigote and intracellular amastigote forms of Trypanosoma cruzi. Ravenelin was active against Gram-positive bacteria strains, with emphasis on Bacillus subtilis (MIC value of 7.5 µM). Ravenelin's antiparasitic activities were assessed against both the epimastigote (IC50 value of 5 ± 1 µM) and the intracellular amastigote forms of T. cruzi (IC50 value of 9 ± 2 µM), as well as against P. falciparum (IC50 value of 3.4 ± 0.4 µM). Ravenelin showed low cytotoxic effects on both HepG2 (CC50 > 50 µM) and peritoneal macrophage (CC50 = 185 ± 1 µM) cells with attractive selectivity for the parasites (SI values > 15). These findings indicate that ravenelin is a natural compound with both antibacterial and antiparasitic activities, and considerable selectivity indexes. Therefore, ravenelin is an attractive candidate for hit-to-lead development.

Marine-Derived Penicillium purpurogenum Reduces Tumor Size and Ameliorates Inflammation in an Erlich Mice Model.

BACKGROUND: This study addresses the antitumoral properties of Penicillium purpurogenum isolated from a polluted lagoon in Northeastern Brazil. METHODS: Ethyl Acetate Extracellular Extract (EAE) was used. The metabolites were studied using direct infusion mass spectrometry. The solid Ehrlich tumor model was used for antitumor activity. Female Swiss mice were divided into groups (n = 10/group) as follows: The negative control (CTL-), treated with a phosphate buffered solution; the positive control (CTL+), treated with cyclophosphamide (25 mg/kg); extract treatments at doses of 4, 20, and 100 mg/kg; animals without tumors or treatments (Sham); and animals without tumors treated with an intermediate dose (EAE20). All treatments were performed intraperitoneally, daily, for 15 days. Subsequently, the animals were euthanized, and the tumor, lymphoid organs, and serum were used for immunological, histological, and biochemical parameter evaluations. RESULTS: The extract was rich in meroterpenoids. All doses significantly reduced tumor size, and the 20 and 100 mg/kg doses reduced tumor-associated inflammation and tumor necrosis. The extract also reduced the cellular infiltration of lymphoid organs and circulating TNF-α levels. The extract did not induce weight loss or renal and hepatic toxic changes. CONCLUSIONS: These results indicate that P. purpurogenum exhibits immunomodulatory and antitumor properties in vivo. Thus, fungal fermentation is a valid biotechnological approach to the production of antitumor agents.

1,4-Disubstituted-1,2,3-Triazole Compounds Induce Ultrastructural Alterations in Leishmania amazonensis Promastigote: An in Vitro Antileishmanial and in Silico Pharmacokinetic Study.

The current standard treatment for leishmaniasis has remained the same for over 100 years, despite inducing several adverse effects and increasing cases of resistance. In this study we evaluated the in vitro antileishmanial activity of 1,4-disubstituted-1,2,3 triazole compounds and carried out in silico predictive study of their pharmacokinetic and toxicity properties. Ten compounds were analyzed, with compound 6 notably presenting IC50: 14.64 ± 4.392 µM against promastigotes, IC50: 17.78 ± 3.257 µM against intracellular amastigotes, CC50: 547.88 ± 3.256 µM against BALB/c peritoneal macrophages, and 30.81-fold selectivity for the parasite over the cells. It also resulted in a remarkable decrease in all the parameters of in vitro infection. Ultrastructural analysis revealed lipid corpuscles, a nucleus with discontinuity of the nuclear membrane, a change in nuclear chromatin, and kinetoplast swelling with breakdown of the mitochondrial cristae and electron-density loss induced by 1,4-disubstituted-1,2,3-triazole treatment. In addition, compound 6 enhanced 2.3-fold the nitrite levels in the Leishmania-stimulated macrophages. In silico pharmacokinetic prediction of compound 6 revealed that it is not recommended for topical formulation cutaneous leishmaniasis treatment, however the other properties exhibited results that were similar or even better than miltefosine, making it a good candidate for further in vivo studies against Leishmania parasites.

The Influence of Anthocyanidin Profile on Antileishmanial Activity of Arrabidaea chica Morphotypes.

Arrabidaea chica Verlot (crajiru) is a plant used in folk medicine as an astringent, anti-inflammatory, wound healing and to treat fungal and viral diseases such as measles chickenpox and herpes. Arrabidaea chica has several morphotypes recognized but little is known about its chemical variability. In the present study the anthocyanidin profile of A. chica morphotypes collected in two seasons (summer and winter) have been examined and their activity against Leishmania infection compared. High-performance liquid chromatography coupled to a diode-array detector (HPLC-DAD-UV) and by tandem mass spectrometry with electrospray ionization (ESI-MS/MS) were used for anthocyanidin separation and identification. Antileishmanial activity was measured against promastigote forms of Leishmania amazonensis. Multivariate analysis, principal component analysis (PCA) and Pearson's correlation were performed to classify morphotypes accordingly to their anthocyanidin profile. The presence of 6,7,3',4'-tetrahydroxy-5-methoxyflavylium (3'-hydroxy-carajurone) (1), carajurone (2), 6,7,3'-trihydroxy-5,4'-dimethoxy-flavylium (3'-hydroxy-carajurin) (3) and carajurin (4), and three unidentified anthocyanidins were detected. Two different groups were recognized: group I containing 3'-hydroxy-carajurone; and group II with high content of carajurin. Among anthocyanidins identified in the extracts, only carajurin showed significant statistical correlation (p = 0.030) with activity against L. amazonensis. Carajurin could thus be considered as a pharmacological marker for the antileishmanial potential of the species.

Endlicheria bracteolata (Meisn.) Essential Oil as a Weapon Against Leishmania amazonensis: In Vitro Assay.

The difficulties encountered and the numerous side effects present in the treatment of cutaneous leishmaniasis have encouraged the research for new compounds that can complement or replace existing treatment. The growing scientific interest in the study of plants, which are already used in folk remedies, has led our group to test Endlicheria bracteolata essential oil against Leishmania amazonensis. Several species of the Lauraceae family, or their compounds, have relevant antiprotozoal activities Therefore, the biological potential on L. amazonensis forms from the essential oil of Endlicheria bracteolata leaves was verified for the first time in that work. The antileishmanial activity was evaluated against promastigotes and intracellular amastigotes, and cytotoxicity were performed with J774.G8, which were incubated with different concentrations of E. bracteolata essential oil. Transmission electron microscopy and flow cytometry were performed with E. bracteolata essential oil IC50. Promastigote forms showed E. bracteolata essential oil IC50 of 7.945 ± 1.285 µg/mL (24 h) and 6.186 ± 1.226 µg/mL (48 h), while for intracellular amastigote forms it was 3.546 ± 1.184 µg/mL (24 h). The CC50 was 15.14 ± 0.090 µg/mL showing that E. bracteolata essential oil is less toxic to macrophages than to parasites. Transmission electron microscopy showed that E. bracteolata essential oil treatment is capable of inducing mitochondrial damage to promastigote and intracellular amastigote forms, while flow cytometry showed ΔÑ°m disruption in treated parasites. These results could bring about new possibilities to develop products based on E. bracteolata essential oil to treat cutaneous leishmaniasis, especially for people who cannot receive the conventional therapy.

Morinda citrifolia Linn. fruit (Noni) juice induces an increase in NO production and death of Leishmania amazonensis amastigotes in peritoneal macrophages from BALB/c.

Leishmaniasis is a complex disease that is considered a serious public health problem. Due to the absence of an effective vaccine and debilitating chemotherapy better therapies are urgently needed. This situation has stimulated the search for alternative treatments such as the use of herbal medicines. Several studies conducted with Morinda citrifolia Linn. have shown various biological activities such as antitumor, immunomodulation and antileishmanial activity, however its mechanisms of action are still unknown. This study aimed to analyze the activity of M. citrifolia fruit juice against Leishmania amazonensis and its action on peritoneal macrophages from BALB/c infected with L. amazonensis. Activity against the promastigote forms showed IC50 at 275.3 µg/mL. Transmission electron microscopy was used to evaluate the ultrastructural alterations in the promastigotes treated with the juice and the results showed cytoplasmic vacuolization, lipid inclusion and increased activity of exocytosis. The juice treatment presented an IC50 at 208.4 µg/mL against intracellular amastigotes and led to an increased nitrite production in infected and non-infected macrophages. When macrophages were pre-treated with iNOS inhibitors, aminoguanidine or 1400W, the intracellular amastigotes increased, demonstrating the important role of NO production in M. citrifolia fruit activity. In conclusion, our results reveal that treatment with M. citrifolia fruit juice can increase NO production in peritoneal macrophages and this ability has an important role in the killing of L. amazonensis intracellular amastigotes.

Leishmanicidal, cytotoxicity and wound healing potential of Arrabidaea chica Verlot.

BACKGROUND: Leishmaniasis includes a wide complex of diseases that affect humans and other mammals, and can range from a mild cutaneous form to a severe visceral type. The safety of the standard treatment using pentavalent antimony is a concern due to its toxic effects. The search for alternative, effective and less toxic treatments has led to the testing of natural products. The present study aimed to evaluate the cytotoxic, leishmanicidal and healing potential of Arrabidaea chica. METHODS: The crude ethanolic extract, as well as the chloroform, methanol and ethyl acetate fractions of A. chica were prepared and phytochemical analysis was performed. Cytotoxic evaluation was carried out through MTT colorimetric assay, and the 50% cellular cytotoxicity was determined. After that, the effect of the extract and fractions against Leishmania amazonensis promastigotes, at intervals of 24, 48 and 72 h, was analyzed, and 50% inhibitory concentration was determined. The healing effect of the plant was also tested in surgical lesions in Swiss mice skin. RESULTS: Phytochemical screening showed that the crude extracts contained flavonoids, tannins, anthocyanidins and chalcones. The leishmanicidal potential of A. chica produced satisfactory results in concentrations of between 60 and 155.9 µg/mL. Cytotoxic assay revealed a 50% reduction in viable cells at a concentration of 189.9 µg/mL. The healing results indicated that the treated group exhibited more pronounced signs of lesion resolution in the early period, but this pattern did not persist throughout the treatment. CONCLUSIONS: The results of the present study demonstrate that A. chica has cytotoxic and leishmanicidal potential but its healing effect must be better studied.

In vitro evaluation of (-)α-bisabolol as a promising agent against Leishmania amazonensis.

Current treatments for leishmaniasis present some difficulties due to their toxicity, the use of the intravenous route for administration and therapy duration, which may lead to treatment discontinuation. The aim of this study is to investigate new treatment alternatives to improve patients well being. Therefore, we evaluated the inhibitory effect of (-)α-bisabolol, a sesquiterpene alcohol found in various essential oils of different plant species, against the promastigotes and intracellular amastigotes forms of Leishmania amazonensis, as well as the cytotoxic, morphological and ultrastructural alterations of treated cells. Promastigotes forms of L. amazonensis were incubated with (-)α-bisabolol to determine the antileishmanial activity of this compound. The cytotoxicity effect was evaluated by testing against J774.G8 cells. After these tests, the infected and uninfected cells with L. amazonensis were used to determine if the (-)α-bisabolol was able to kill intracellular parasites and to cause some morphological changes in the cells. The (-)α-bisabolol compound showed significant antileishmanial activity against promastigotes with a 50% effective concentration of 8.07 µg/ml (24 h) and 4.26 µg/ml (48 h). Against intracellular amastigotes the IC50 (inhibitory concentration) of (-)α-bisabolol (24 h) was 4.15 µg/ml. The (-)α-bisabolol also showed a cytotoxic effect against the macrophage strain J774.G8. The value of 50% cytotoxic concentration was 14.82 µg/ml showing that (-)α-bisabolol is less toxic to macrophages than to the parasite. Ultrastructural studies of treated promastigotes and amastigotes showed several alterations, such as loss of cytoplasmic organelles, including the nucleus, and the presence of lipid inclusions. This study showed that (-)α-bisabolol has promising antileishmanial properties, as it can act against the promastigote forms and is able to penetrate the cell, and is also active against the amastigote forms. About 69% of the promastigotes forms suffered mitochondrial membrane damage after treatment with IC50 of (-)α-bisabolol, suggesting inhibition of the metabolic activity of parasites. These results open new prospects for research that can contribute to the development of products based on essential oils or isolated compounds from plants for the treatment of cutaneous leishmaniasis.

Leishmanicidal and immunomodulatory activity of Terminalia catappa in Leishmania amazonensisin vitro infection.

Leishmaniases are infectious-parasitic diseases that impact public health around the world. Antileishmanial drugs presented toxicity and increase in parasitic resistance. Studies with natural products show an alternative to this effect, and several metabolites have demonstrated potential in the treatment of various diseases. Terminalia catappa is a plant species with promising pharmaceutical properties. The objective of this work was to evaluate the therapeutic potential of extracts and fractions of T. catappa on Leishmania amazonensis and investigate the immunomodulatory mechanisms associated with its action. In anti-Leishmania assays, the ethyl acetate fraction exhibited activity against promastigotes (IC50 86.07 ± 1.09 µg/mL) and low cytotoxicity (CC50 517.70 ± 1.68 µg/mL). The ethyl acetate fraction also inhibited the intracellular parasite (IC50 25.74 ± 1.08 µg/mL) with a selectivity index of 20.11. Treatment with T. catappa ethyl acetate fraction did not alter nitrite production by peritoneal macrophages stimulated with L. amazonensis, although there was a decrease in unstimulated macrophages treated at 50 µg/mL (p = 0.0048). The T. catappa ethyl acetate fraction at 100 µg/mL increased TNF-α levels (p = 0.0238) and downregulated HO-1 (p = 0.0030) and ferritin (p = 0.0002) gene expression in L. amazonensis-stimulated macrophages. Additionally, the total flavonoid and ellagic acid content for ethyl acetate fraction was 13.41 ± 1.86 mg QE/g and 79.25 mg/g, respectively. In conclusion, the T. catappa ethyl acetate fraction showed leishmanicidal activity against different forms of L. amazonensis and displayed immunomodulatory mechanisms, including TNF-α production and expression of pro and antioxidant genes.

In Vitro Antioxidant and Antitrypanosomal Activities of Extract and Fractions of Terminalia catappa.

Chagas disease is a severe infectious and parasitic disease caused by the protozoan Trypanosoma cruzi and considered a public health problem. Chemotherapeutics are still the main means of control and treatment of the disease, however with some limitations. As an alternative treatment, plants have been pointed out due to their proven pharmacological properties. Many studies carried out with Terminalia catappa have shown several biological activities, but its effect against T. cruzi is still unknown. The objective of this work is to evaluate the therapeutic potential of extracts and fractions obtained from T. catappa on the parasite T. cruzi, in addition to analyzing its antioxidant activity. T. catappa ethyl acetate fraction were produced and submitted the chemical characterization by Liquid Chromatography Coupled to Mass Spectrometry (LC-MS). From all T. catappa extracts and fractions evaluated, the ethyl acetate and the aqueous fraction displayed the best antioxidant activity by the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging method (IC50 of 7.77 ± 1.61 and 5.26 ± 1.26 µg/mL respectively), and by ferric ion reducing (FRAP) method (687.61 ± 0.26 and 1009.32 ± 0.13 µM of Trolox equivalent/mg extract, respectively). The ethyl acetate fraction showed remarkable T. cruzi inhibitory activity with IC50 of 8.86 ± 1.13, 24.91 ± 1.15 and 85.01 ± 1.21 µg/mL against epimastigotes, trypomastigotes and intracellular amastigotes, respectively, and showed no cytotoxicity for Vero cells (CC50 > 1000 µg/mL). The treatment of epimastigotes with the ethyl acetate fraction led to drastic ultrastructural changes such as the loss of cytoplasm organelles, cell disorganization, nucleus damage and the loss of integrity of the parasite. This effect could be due to secondary compounds present in this extract, such as luteolin, kaempferol, quercetin, ellagic acid and derivatives. The ethyl acetate fraction obtained from T. catappa leaves can be an effective alternative in the treatment and control of Chagas disease, and material for further investigations.

Effects of Passovia ovata Mistletoe on Pro-Inflammatory Markers In Vitro and In Vivo.

New agents that can suppress inflammatory responses are being sought, since chronic inflammation is associated with several pathologies. This work aims to elucidate phytochemicals from the hydroethanolic extract of mistletoe Passovia ovata (POH) and its anti-inflammatory potential. POH is submitted to HPLC-UV, qualitative analysis of chemical constituents, and flavonoid quantification. Cytotoxicity is evaluated in RAW 264.7 macrophages by MTT. LPS-stimulated RAW 264.7 cells are treated with POH and, after 48 h, the nitrite and cytokine levels are quantified. BALB/c mice are treated by gavage with POH and stimulated with λ-carrageenan to induce paw oedema or peritonitis. POH yield is 25% with anthraquinones, tannins, anthocyanins, anthocyanidins, flavonols, catechins and flavanones present and flavonoid content of 4.44 ± 0.157 mg QE/g dry weight. POH exhibits low cytotoxicity and significantly reduced (p < 0.01) nitrite, IL-1ß, IL-6, and TNF-α quantification at 500 µg/mL. POH at 500 mg/kg prevents paw edema increase and also reduces inflammatory infiltrate and mast cells in the footpad. In the peritonitis model, POH does not influence cytokines levels or cell counts. Overall, POH demonstrates a high concentration of flavonoids and prominent effects in the reduction in pro-inflammatory markers in vitro and in the inhibition of paw oedema.

(-)-5-Demethoxygrandisin B a New Lignan from Virola surinamensis (Rol.) Warb. Leaves: Evaluation of the Leishmanicidal Activity by In Vitro and In Silico Approaches.

Leishmaniasis is a complex disease caused by infection with different Leishmania parasites. The number of medications used for its treatment is still limited and the discovery of new drugs is a valuable approach. In this context, here we describe the in vitro leishmanicidal activity and the in silico interaction between trypanothione reductase (TryR) and (-)-5-demethoxygrandisin B from the leaves of Virola surinamensis (Rol.) Warb. The compound (-)-5-demethoxygrandisin B was isolated from V. surinamensis leaves, a plant found in the Brazilian Amazon, and it was characterized as (7R,8S,7'R,8'S)-3,4,5,3',4'-pentamethoxy-7,7'-epoxylignan. In vitro antileishmanial activity was examined against Leishmania amazonensis, covering both promastigote and intracellular amastigote phases. Cytotoxicity and nitrite production were gauged using BALB/c peritoneal macrophages. Moreover, transmission electron microscopy was applied to probe ultrastructural alterations, and flow cytometry assessed the shifts in the mitochondrial membrane potential. In silico methods such as molecular docking and molecular dynamics assessed the interaction between the most stable configuration of (-)-5-demethoxygrandisin B and TryR from L. infantum (PDB ID 2JK6). As a result, the (-)-5-demethoxygrandisin B was active against promastigote (IC50 7.0 µM) and intracellular amastigote (IC50 26.04 µM) forms of L. amazonensis, with acceptable selectivity indexes. (-)-5-demethoxygrandisin B caused ultrastructural changes in promastigotes, including mitochondrial swelling, altered kDNA patterns, vacuoles, vesicular structures, autophagosomes, and enlarged flagellar pockets. It reduced the mitochondria membrane potential and formed bonds with important residues in the TryR enzyme. The molecular dynamics simulations showed stability and favorable interaction with TryR. The compound targets L. amazonensis mitochondria via TryR enzyme inhibition.

Antitumor Effect of Açaí (Euterpe oleracea Mart.) Seed Extract in LNCaP Cells and in the Solid Ehrlich Carcinoma Model.

Euterpe oleracea (açaí) fruit has approximately 15% pulp, which is partly edible and commercialized, and 85% seeds. Although açaí seeds are rich in catechins-polyphenolic compounds with antioxidant, anti-inflammatory, and antitumor effects-almost 935,000 tons/year of seeds are discarded as industrial waste. This work evaluated the antitumor properties of E. oleracea in vitro and in vivo in a solid Ehrlich tumor in mice. The seed extract presented 86.26 ± 0.189 mg of catechin/g of extract. The palm and pulp extracts did not exhibit in vitro antitumor activity, while the fruit and seed extracts showed cytotoxic effects on the LNCaP prostate cancer cell line, inducing mitochondrial and nuclear alterations. Oral treatments were performed daily at 100, 200, and 400 mg/kg of E. oleracea seed extract. The tumor development and histology were evaluated, along with immunological and toxicological parameters. Treatment at 400 mg/kg reduced the tumor size, nuclear pleomorphism, and mitosis figures, increasing tumor necrosis. Treated groups showed cellularity of lymphoid organs comparable to the untreated group, suggesting less infiltration in the lymph node and spleen and preservation of the bone marrow. The highest doses reduced IL-6 and induced IFN-γ, suggesting antitumor and immunomodulatory effects. Thus, açaí seeds can be an important source of compounds with antitumor and immunoprotective properties.

Phomoxanthone A, Compound of Endophytic Fungi Paecilomyces sp. and Its Potential Antimicrobial and Antiparasitic.

The present work reports the isolation and biological evaluation of three dimeric xanthones from Paecilomyces sp. EJC01.1 isolated as endophytic from Schnella splendens, a typical plant of the Amazon. The compounds phomoxanthone A (1), phomoxanthone B (2) and dicerandrol B (3) were isolated by chromatographic procedures and identified by spectroscopic methods of 1D and 2D NMR and MS. The extracts and compound 1 showed antimicrobial activities against Bacillus subtilis, Escherichia coli, Staphylococcus aureus, Salmonella typhimurium and Pseudomonas aeruginosa. The compound phomoxanthone A (1) showed greater inhibitory activity against B. subtilis (MIC of 7.81 µg mL-1); in addition, it also pronounced inhibitory effect against promastigote forms of Leishmania amazonensis (IC50 of 16.38 ± 1.079 µg mL-1) and epimastigote forms Trypanosoma cruzi (IC50 of 28.61 ± 1.071 µg mL-1). To provide more information about the antibacterial activity of compound 1, an unprecedented molecular docking study was performed using S-ribosyl-homocysteine lyase (LuxS) (PDB ID 2FQO), which showed a possible interaction of phomoxanthone A with two of the residues (His58 and Cys126) that are fundamental for the catalysis mechanism in B. subtilis, which may be associated with the higher activity, when compared to other bacteria, observed in experimental studies. Additionally, quantum studies (DFT) were performed, for which a low gap value (5.982 eV) was observed, which corroborates the reactivity of phomoxanthone A. Thus, phomoxanthone A can be a good agent against pathogenic bacteria.

Amentoflavone isolated from Selaginella sellowii Hieron induces mitochondrial dysfunction in Leishmania amazonensis promastigotes.

Leishmaniasis chemotherapy is a bottleneck in disease treatment. Although available, chemotherapy is limited, toxic, painful, and does not lead to parasite clearance, with parasite resistance also being reported. Therefore, new therapeutic options are being investigated, such as plant-derived anti-parasitic compounds. Amentoflavone is the most common biflavonoid in the Selaginella genus, and its antileishmanial activity has already been described on Leishmania amazonensis intracellular amastigotes but its direct action on the parasite is controversial. In this work we demonstrate that amentoflavone is active on L. amazonensis promastigotes (IC50 = 28.5 ± 2.0 µM) and amastigotes. Transmission electron microscopy of amentoflavone-treated promastigotes showed myelin-like figures, autophagosomes as well as enlarged mitochondria. Treated parasites also presented multiple lipid droplets and altered basal body organization. Similarly, intracellular amastigotes presented swollen mitochondria, membrane fragments in the lumen of the flagellar pocket as well as autophagic vacuoles. Flow cytometric analysis after TMRE staining showed that amentoflavone strongly decreased mitochondrial membrane potential. In silico analysis shows that amentoflavone physic-chemical, drug-likeness and bioavailability characteristics suggest it might be suitable for oral administration. We concluded that amentoflavone presents a direct effect on L. amazonensis parasites, causing mitochondrial dysfunction and parasite killing. Therefore, all results point for the potential of amentoflavone as a promising candidate for conducting advanced studies for the development of drugs against leishmaniasis.

Carajurin Induces Apoptosis in Leishmania amazonensis Promastigotes through Reactive Oxygen Species Production and Mitochondrial Dysfunction.

Carajurin is the main constituent of Arrabidaea chica species with reported anti-Leishmania activity. However, its mechanism of action has not been described. This study investigated the mechanisms of action of carajurin against promastigote forms of Leishmania amazonensis. Carajurin was effective against promastigotes with IC50 of 7.96 ± 1.23 µg.mL-1 (26.4 µM), and the cytotoxic concentration for peritoneal macrophages was 258.2 ± 1.20 µg.mL-1 (856.9 µM) after 24 h of treatment. Ultrastructural evaluation highlighted pronounced swelling of the kinetoplast with loss of electron-density in L. amazonensis promastigotes induced by carajurin treatment. It was observed that carajurin leads to a decrease in the mitochondrial membrane potential (p = 0.0286), an increase in reactive oxygen species production (p = 0.0286), and cell death by late apoptosis (p = 0.0095) in parasites. Pretreatment with the antioxidant NAC prevented ROS production and significantly reduced carajurin-induced cell death. The electrochemical and density functional theory (DFT) data contributed to support the molecular mechanism of action of carajurin associated with the ROS generation, for which it is possible to observe a correlation between the LUMO energy and the electroactivity of carajurin in the presence of molecular oxygen. All these results suggest that carajurin targets the mitochondria in L. amazonensis. In addition, when assessed for its drug-likeness, carajurin follows Lipinski''s rule of five, and the Ghose, Veber, Egan, and Muegge criteria.

Monomethylsulochrin isolated from biomass extract of Aspergillus sp. against Leishmania amazonensis: In vitro biological evaluation and molecular docking.

Leishmaniasis represents a serious world health problem, with 1 billion people being exposed to infection and a broad spectrum of clinical manifestations with a potentially fatal outcome. Based on the limitations observed in the treatment of leishmaniasis, such as high cost, significant adverse effects, and the potential for drug resistance, the aim of the present study was to evaluate the leishmanicidal activity of the compounds pseurotin A and monomethylsulochrin isolated from the biomass extract of Aspergillus sp. The chromatographic profiles of the extract were determined by high-performance liquid chromatography coupled with a diode-array UV-Vis detector (HPLC-DAD-UV), and the molecular identification of the pseurotin A and monomethylsulochrin were carried out by electrospray ionization mass spectrometry in tandem (LC-ESI-MS-MS) and nuclear magnetic resonance (NMR). Antileishmanial activity was assayed against promastigote and intracellular amastigote of Leishmania amazonensis. As a control, cytotoxicity assays were performed in non-infected BALB/c peritoneal macrophages. Ultrastructural alterations in parasites were evaluated by transmission electron microscopy. Changes in mitochondrial membrane potential were determined by flow cytometry. Only monomethylsulochrin inhibited the promastigote growth (IC50 18.04 ± 1.11 µM), with cytotoxicity to peritoneal macrophages (CC50 5.09 91.63 ± 1.28 µM). Activity against intracellular amastigote forms (IC50 5.09 ± 1.06 µM) revealed an increase in antileishmanial activity when compared with promastigotes. In addition to a statistically significant reduction in the evaluated infection parameters, monomethylsulochrin altered the ultrastructure of the promastigote forms with atypical vacuoles, electron-dense corpuscles in the cytoplasm, changes at the mitochondria outer membrane and abnormal disposition around the kinetoplast. It was showed that monomethylsulochrin leads to a decrease in the mitochondrial membrane potential (25.9%, p = 0.0286). Molecular modeling studies revealed that monomethylsulochrin can act as inhibitor of sterol 14-alpha-demethylase (CYP51), a therapeutic target for human trypanosomiasis and leishmaniasis. Assessed for its drug likeness, monomethylsulochrin follows the Lipinski Rule of five and Ghose, Veber, Egan, and Muegge criteria. Furthermore, monomethylsulochrin can be used as a reference in the development of novel and therapeutically useful antileishmanial agents.

Nitric Oxide Induction in Peritoneal Macrophages by a 1,2,3-Triazole Derivative Improves Its Efficacy upon Leishmania amazonensis In Vitro Infection.

1,2,3-Triazole is one of the most flexible chemical scaffolds broadly used in various fields. Here, we report the antileishmanial activity of 1,2,3-triazole derivatives, the ultrastructural alterations induced by their treatment, and the nitric oxide (NO) modulation effect on their efficacy against Leishmania amazonensis in vitro infection. After the screening of eleven compounds, compound 4 exhibited better results against L. amazonensis promastigotes (IC50 = 15.52 ± 3.782 µM) and intracellular amastigotes (IC50 = 4.10 ± 1.136 µM), 50% cytotoxicity concentration at 84.01 ± 3.064 µM against BALB/c peritoneal macrophages, and 20.49-fold selectivity for the parasite over the cells. Compound 4 induced ultrastructural mitochondrial alterations and lipid inclusions in L. amazonensis promastigotes, upregulated tumor necrosis factor α, interleukin (IL)-1ß, IL-6, IL-12, and IL-10 messenger RNA expressions, and enhanced the NO production, verified by nitrite (p = 0.0095) and inducible nitric oxide synthase expression (p = 0.0049) quantification, which played an important role in its activity against intramacrophagic L. amazonensis. In silico prediction in association with antileishmanial activity results showed compound 4 as a hit compound with promising potential for further studies of new leishmaniasis treatment options.