Synthesis, design, and optimization of a potent and selective series of pyridylpiperazines as promising antimalarial agents.

An optimization of the pyridylpiperazine series against Plasmodium falciparum has been performed, exploring a structure-activity relationship carried out on the toluyl fragment of hit 1, a compound with low micromolar activity against Plasmodium falciparum discovered by high-throughput screening. After confirming the crucial role played by this aryl fragment in the antiplasmodial activity, the replacement of the ortho-methyl substituent of 1 by halogenated ones led to an improvement for four analogs, either in terms of potency, expected pharmacokinetics profile, or both. Further introduction of endocyclic nitrogens in this fragment identified two more optimized compounds, 20 and 23, which are expected to be much more metabolically stable than 1. Additional assessment of the cytotoxicity, Ligand Lipophilic Efficiency, potency against the chloroquine-resistant Dd2 strain and in silico ADMET predictions revealed a satisfactory profile for most compounds, ultimately identifying the four optimized compounds 7, 9, 20 and 23 as promising compounds for further lead optimization of this series against Plasmodium falciparum.

Evaluation and discovery of novel benzothiazole derivatives as promising hits against Leishmania infantum.

An early exploration of the benzothiazole class against two kinetoplastid parasites, Leishmania infantum and Trypanosoma cruzi, has been performed after the identification of a benzothiazole derivative as a suitable antileishmanial initial hit. The first series of derivatives focused on the acyl fragment of its class, evaluating diverse linear and cyclic, alkyl and aromatic substituents, and identified two other potent compounds, the phenyl and cyclohexyl derivatives. Subsequently, new compounds were designed to assess the impact of the presence of diverse substituents on the benzothiazole ring or the replacement of the endocyclic sulfur by other heteroatoms. All compounds showed relatively low cytotoxicity, resulting in decent selectivity indexes for the most active compounds. Ultimately, the in vitro ADME properties of these compounds were assessed, revealing a satisfying water solubility, gastrointestinal permeability, despite their low metabolic stability and high lipophilicity. Consequently, compounds 5 and 6 were identified as promising hits for further hit-to-lead exploration within this benzothiazole class against L. infantum, thus providing promising starting points for the development of antileishmanial candidates.

Metabolomic kinetics investigation of Camellia sinensis kombucha using mass spectrometry and bioinformatics approaches.

Kombucha is created through the fermentation of Camellia sinensis tea leaves, along with sucrose, utilizing a symbiotic consortium of bacteria and yeast cultures. Nonetheless, there exists a dearth of comprehensive information regarding the spectrum of metabolites that constitute this beverage. To explore this intricate system, metabolomics was used to investigate fermentation kinetics of Kombucha. For that, an experimental framework was devised to assess the impact of varying sucrose concentrations and fermentation temperatures over a ten-day period of kombucha fermentation. Following fermentation, samples were analyzed using an LC-QTOF-MS system and a distinctive metabolomic profile was observed. Principal component analysis was used to discriminate between metabolite profiles. Moreover, the identified compounds were subjected to classification using the GNPS platform. The findings underscore notable differences in compound class concentrations attributable to distinct fermentation conditions. Furthermore, distinct metabolic pathways were identified, specially some related to the biotransformation of flavonoids. This comprehensive investigation offers valuable insights into the pivotal role of SCOBY in driving metabolite production and underscores the potential bioactivity harbored within Kombucha.

Optimization of benzenesulfonyl derivatives as anti-Trypanosomatidae agents: Structural design, synthesis, and pharmacological assessment against Trypanosoma cruzi and Leishmania infantum.

Leishmaniasis and Chagas disease are neglected tropical diseases caused by Trypanosomatidae parasites. Given the numerous limitations associated with current treatments, such as extended treatment duration, variable efficacy, and severe side effects, there is an urgent imperative to explore novel therapeutic options. This study details the early stages of hit-to-lead optimization for a benzenesulfonyl derivative, denoted as initial hit, against Trypanossoma cruzi (T. cruzi), Leishmania infantum (L. infantum) and Leishmania braziliensis (L. braziliensis). We investigated structure - activity relationships using a series of 26 newly designed derivatives, ultimately yielding potential lead candidates with potent low-micromolar and sub-micromolar activities against T. cruzi and Leishmania spp, respectively, and low in vitro cytotoxicity against mammalian cells. These discoveries emphasize the significant promise of this chemical class in the fight against Chagas disease and leishmaniasis.

Stilbenes, phenanthrenes and antiproliferative activity of Cattleya intermedia.

The phytochemical study of Cattleya intermedia (Orchidaceae) led to the isolation of two new stilbenoids and one new 9,10-dihydrophenanthrene, 4',5-dihydroxy-2',3-dimethoxy-dihydrostilbene (1), 3,6'-dihydroxy-4'-methoxy-dihydrostilbene (2) and 1,2,6-trihydroxy-3,8-dimethoxy-9,10-dihydrophenanthrene (3), named cattleymediol, cattleyol and phenanmediol, respectively, in addition to other five known compounds (4-8). The structural elucidations of the isolated compounds were carried out through the analyses of the one-dimensional 1H,1³C and NOE NMR spectra, and the 2D HSQC, HMBC, COSY and NOESY spectra, besides high-resolution mass spectrometry. In addition to this, the crude extract and its main fractions were analysed by ultra-high performance liquid chromatography coupled to high resolution mass spectrometry (UHPLC-QTOF-MS/MS), leading to the putative identification of several other compounds, including flavonoids and organic acids derivatives. Finally, the main fractions of the crude extract, and the pure compounds cattleymediol (1) and lusiantridine (7), had their antiproliferative activities evaluated against human cancerous HeLa and non-cancerous VERO cells.

Bioactive compounds by UHPLC-MS/MS and molecular networking from Myrceugenia foveolata.

Myrceugenia foveolata, commonly known as 'guamirim', was analysed using UHPLC-MS/MS and molecular networking. Hydroalcoholic extracts of leaves and stem bark were obtained using ethanol:water (70:30) as solvent. Chemical composition of the extracts was identified using UHPLC-MS/MS and tested for antioxidant activity and growth inhibition against E. coli, S. aureus, L. monocytogenes and S. enterica. Ten compounds were tentatively identified in the extracts including myricitrin, quercitrin, and betulin (in leave extracts), and avicularin, kaemferol-3-O-arabinopyroniside, 2"-O-galloylquercitrin and the acid triterpenes ursolic, sumaresinolic, asiatic and maslinic (in both extracts). Both extracts showed similar antioxidant activities, phenolic composition, and growth inhibition. The most pronounced response was observed against L. monocytogenes, with a growth inhibition rate of 73% to leaves extract and 65% do stem bark extract.

Discovery and structural optimization of a new series of N-acyl-2-aminobenzothiazole as inhibitors of Zika virus.

Zika virus infection is associated to severe diseases such as congenital microcephaly and Zika fever causing serious harm to humans and special concern to health systems in low-income countries. Currently, there are no approved drugs against the virus, and the development of anti-Zika virus drugs is thus urgent. The present investigation describes the discovery and hit expansion of a N-acyl-2-aminobenzothiazole series of compounds against Zika virus replication. A structure-activity relationship study was obtained with the synthesis and evaluation of anti-Zika virus activity and cytotoxicity on Vero cells of nineteen derivatives. The three optimized compounds were 2.2-fold more potent than the initial hit and 20.9, 7.7 and 6.4-fold more selective. Subsequent phenotypic and biochemical assays were performed to evidence whether non-structural proteins, such as the complex NS2B-NS3pro, are related to the mechanism of action of the most active compounds.

Synthesis of 1,2,3-Triazole-Containing Methoxylated Cinnamides and Their Antileishmanial Activity against the Leishmania braziliensis Species.

Leishmaniasis is a group of infectious diseases caused by protozoan parasites that belong to the genus Leishmania. Currently, there is no human vaccine, and the available treatments are associated with toxicity, high cost, and the emergence of resistant strains. These factors highlight the need to identify new antileishmanial candidates. In this study, we synthesized twenty-four methoxylated cinnamides containing 1,2,3-triazole fragments and evaluated their antileishmanial activity against the Leishmania braziliensis species, which is the main etiological agent responsible for American Tegumentary Leishmaniasis (ATL). The cinnamides were synthetically prepared using nucleophilic acyl substitution and copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reactions. The compounds were characterized using infrared, nuclear magnetic resonance, and high-resolution mass spectrometry techniques. We performed preliminary studies to evaluate the biological activity of these compounds against L. braziliensis promastigotes and axenic amastigotes. Compound 28, N-((1-(7-(diethylamino)-2-oxo-2H-chromen-3-yl)-1H-1,2,3-triazole-4-yl) methyl)-3,4-dimethoxy cinnamide, demonstrated relevant antileishmanial activity with low toxicity in murine cells. The selectivity index values for this compound were superior compared with data obtained using amphotericin B. Furthermore, this cinnamide derivative reduced the infection percentage and number of recovered amastigotes in L. braziliensis-infected macrophages. It also induced an increase in reactive oxygen species production, depolarization of the mitochondrial potential, and disruption of the parasite membrane. Taken together, these findings suggest that this synthetic compound holds potential as an antileishmanial candidate and should be considered for future studies in the treatment of ATL.

Ultrasonication and thermosonication applied in the processing of jalapeno pepper (Capsicum annuum var. annuum) sauce.

Ultrasonication is one of the non-thermal physical methods that can be used on foods and when used in synergy with temperature (thermosonication), this technique proves to be more effective, thus reducing the duration and intensity of heat treatment and the consequent damage to the foods. This work aimed to use the technique of ultrasonication and thermosonication in the processing of jalapeno pepper sauces in comparison with pasteurization. Two types of sauces were produced, one with pre-cooking (a) and the other without cooking (b), and the influence of time and temperature was analyzed by applying ultrasonication and thermosonication. Times of 15 and 30 min and temperatures of 25 and 65 °C were used. Both treatments stood out for their effectiveness when compared to the traditional method (pasteurization 65 °C and 30 min). The results demonstrate that, in general, the sauces are good sources of phenolic compounds (141.83 ± 0.10 mg gallic acid equivalent/100 g), flavonoids (50.40 ± 0.30 mg quercetin equivalent/100 g) and carotenoids (2.39 ± 0.07 mg ß-carotene/100 g). The sauces had an increase in carotenoids by about 25% (thermosonicated at 15 and 30 min and pre-cooked) and in antioxidant activity (ferric reducing antioxidant power) with about 12% and 13% (thermosonicated at 30 min with and without cooking, respectively) in relation to control (pasteurization). On comparing thermosonication with ultrasound process total phenolics had improved by around 14% and flavonoids by 55%. At the first time, capsantin, capsaicin, dihydrocapsaicin, and nordihydrocapsaicin were identified by ultra-high performance liquid chromatography-MS/MS (UHPLC-MS/MS). Finally, as both treatments demonstrate efficiency (thermosonication at 15 and 30 min), the use of 15 min is indicated as feasible by the reduced process time and in preventing the loss of bioactive compounds in the sauces when compared to the pasteurization treatment.

Hit-to-lead optimization of a pyrazinylpiperazine series against Leishmania infantum and Leishmania braziliensis.

An early hit-to-lead optimization of a novel pyrazinylpiperazine series against L. infantum and L. braziliensis has been performed after an extensive SAR focusing on the benzoyl fragment of hit (4). Deletion of the meta-Cl of (4) led to the obtention of the para-hydroxyl derivative (12), on which the design of most monosubstituted derivatives of the SAR was based. Further optimization of the series, involving disubstituted benzoyl fragments and the hydroxyl substituent of (12), allowed the obtention of a total of 15 compounds with increased antileishmanial potency (IC50 < 10 µM), nine of which displayed activity in the low micromolar range (IC50 < 5 µM). This optimization ultimately identified the ortho, meta-dihydroxyl derivative (46) as an early lead for this series (IC50 (L. infantum) = 2.8 µM, IC50 (L. braziliensis) = 0.2 µM). Additional assessment of some selected compounds against other trypanosomatid parasites revealed that this series is selective towards Leishmania parasites, and in silico ADMET predictions revealed satisfactory profiles for these compounds, allowing further lead optimization of the pyrazinylpiperazine class against Leishmania.

Proteomic Investigation over the Antimicrobial Photodynamic Therapy Mediated by Rose Bengal Against Staphylococcus aureus.

In order, understanding the antimicrobial action of photodynamic therapy and how this technique can contribute to its application in the control of pathogens. The objective of the study was to employ a proteomic approach to investigate the protein profile of Staphylococcus aureus after antimicrobial photodynamic therapy mediated by rose bengal (RB-aPDT). S. aureus was treated with RB (10 nmoL L-1 ) and illuminated with green LED (0.17 J cm-2 ) for cell viability evaluation. Afterward, proteomic analysis was employed for protein identification and bioinformatic tools to classify the differentially expressed proteins. The reduction in S. aureus after photoinactivation was ~2.5 log CFU mL-1 . A total of 12 proteins (four up-regulated and eight down-regulated) correspond exclusively to alteration by RB-aPDT. Functionally, these proteins are distributed in protein binding, structural constituent of ribosome, proton transmembrane transporter activity and ATPase activity. The effects of photodamage include alterations of levels of several proteins resulting in an activated stress response, altered membrane potential and effects on energy metabolism. These 12 proteins required the presence of both light and RB suggesting a unique response to photodynamic effects. The information about this technique contributes valuable insights into bacterial mechanisms and the mode of action of photodynamic therapy.

Ultra-high-performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight mass spectrometry and molecular networking analysis to investigate the chemodiversity of bioactive extracts of Annona jahnii Saff. fungi from the Brazilian Amazon.

RATIONALE: Annona species are of interest for the isolation of bioactive molecules; however, studies of Annona jahnii Saff. are limited. The exploration of bioactive metabolites of endophytes isolated from this species is unprecedented and allows the preservation of the host plant, in addition to enabling the discovery of compounds with promising biological activities. METHODS: Ethyl acetate extracts from the cultured media of five fungi were obtained. The antioxidant capacity of the extracts was measured using the 1,1-diphenyl-2-picrylhydrazyl free radical method. Antimicrobial activity was determined using the microdilution method in broth in 96-well plates. The exploration of the metabolic profile of the extracts and dereplication of the compounds were performed using ultra-high-performance liquid chromatography/electrospray ionization/tandem mass spectrometry (UHPLC/ESI-MS/MS) combined with analysis using molecular networking (MN). RESULTS: A total of 1818 MS features were detected in the five selected extracts, of which 39 compounds were putatively identified. The secondary metabolites with the highest abundance were alkaloids, naphthopyrons, and cytochalasins. Other secondary metabolites include fumonisins, coumarin, and a meroterpenoid. Most of these compounds are related to specific biological properties such as antioxidant, anti-inflammatory, antimicrobial, antiviral, and antitumor activities. Extracts F398 and F403 showed inhibitory activity of the four pathogens tested. Extracts F475 and F506 did not inhibit the growth of Staphylococcus aureus, and F407 did not inhibit the growth of Escherichia coli in addition to having potent antioxidant activity, with IC50 values of 10 µg/mL or less. CONCLUSIONS: The use of UHPLC/ESI-MS/MS data combined with MN proved useful in the dereplication of bioactive molecules of complex extracts that are still unexplored. These initial investigations should significantly assist in further research and increase the efficiency and speed in the discovery of new sources of secondary metabolites and new natural products.

Molecular network-guided chemical profile and mass spectrometry, volatile compounds, and antimicrobial activity of Scaptotrigona depilis propolis.

RATIONALE: Propolis has a great diversity in its composition due to numerous factors; therefore, each study is an important contribution to the knoFwledge of its composition and biological action. The objective of this study was to determine the chemical profile and biological activity of propolis produced by Scaptotrigona depilis. METHODS: Extracts with 70% ethanol (EPE70) and with cereal alcohol (CAPE) were elaborated, and then characterized using UHPLC-ESI(+)-MS/MS. Volatile compounds were extracted and then characterized using gas chromatography mass spectrometry (GC-MS). In addition, antimicrobial activities were verified against resistant strains. RESULTS: The volatile compounds of propolis predominantly consist of sesquiterpenes. Using the exploratory metabolomic approach, compounds of different classes were putatively identified in the ethanolic extracts, of which the most representative were terpenes, and some of the sesquiterpenes identified among the volatiles were also detected. The extracts were shown to be active against Escherichia coli and Staphylococcus aureus bacteria with a minimum inhibitory concentration (MIC) of 0.5 and 1.0 mg mL-1 , respectively. CONCLUSIONS: The molecular network approach proved to be determining the chemical profile of S. depilis propolis rapidly and accurately, and led to the identification of lipophilic compounds. The identification of compounds using GC-MS and UHPLC-ESI(+)-MS/MS is complementary and useful for the characterization of propolis.

Biological Characterization and Antimicrobial Bioactives of Mycelium Extracts from Medicinal Mushrooms Phellinus linteus and Pleurotus albidus (Agaricomycetes).

Bioactivity is defined as the intrinsic property of compounds that enables their participation in specific biological reactions. This study aimed to evaluate the antimicrobial capacity and to separate and characterize bioactives from aqueous and hydroalcoholic extracts obtained from the mycelium of medicinal mushrooms Pleurotus albidus and Phellinus linteus. Antimicrobial activity, through the disc diffusion method, was found against strains of Bacillus cereus, B. subtilis, Pseudomonas aeruginosa, and Staphylococcus aureus. P. albidus extracts showed better activity against Bacillus strains, whereas Ph. linteus extracts had greater effectiveness against S. aureus and P. aeruginosa. Aqueous extraction was best for obtaining bioactive compounds of P. albidus, whereas 30% hydralcoholic extraction performed best for obtaining Ph. linteus. Mass spectrometry analyses allowed the identification of the main chemical compounds extracted from the fungal biomasses, including glutathione oxidase, leucovorin, and riboflavin. Taking these findings into consideration, P. albidus and Ph. linteus might be used as sources of bioactive molecules for the development of novel drugs or nutraceuticals, contributing to the improvement of public health.

Cereus peruvianus Mill. (Cactaceae) as a source of natural antioxidants: Phenolic compounds and antioxidant activity of cladode extracts in two collection periods.

The economic potential of the cactus species Cereus peruvianus Mill. (syn. C. hildmannianus K. Schum.) has already been demonstrated through the generation of products and patents. However, the phenolic compounds and antioxidant activity have not yet been evaluated. The aim of our study was to determine the total phenolic compounds, evaluate the antioxidant activity and characterize the phenolic compounds of cladode extracts from C. peruvianus grown in the southern region of Brazil, in two collection periods. Higher total content of phenolic compounds and antioxidant activity were detected in the cladode extract collected in 2016 than in the cladode extract collected in 2015. The profile of phenolic compounds identified five flavonoids that had not previously been reported in species of the genus Cereus. The phenolic compounds linked to antioxidant activities identified in the cladode extract from C. peruvianus support the use of this species in human food as a source of natural antioxidants.

Characterization of Secondary Structure and Thermal Stability by Biophysical Methods of the D-alanyl,D-alanine Ligase B Protein from Escherichia coli.

BACKGROUND: Peptidoglycan (PG) is a key structural component of the bacterial cell wall and interruption of its biosynthesis is a validated target for antimicrobials. Of the enzymes involved in PG biosynthesis, D-alanyl,D-alanine ligase B (DdlB) is responsible for the condensation of two alanines, forming D-Ala-D-Ala, which is required for subsequent extracellular transpeptidase crosslinking of the mature peptidoglycan polymer. OBJECTIVE: We aimed at the biophysical characterization of recombinant Escherichia coli DdlB (EcDdlB), considering parameters of melting temperature (Tm), calorimetry and Van't Hoff enthalpy changes of denaturation ( ΔHUcal and ΔHUvH ), as well as characterization of elements of secondary structure at three different pHs. METHODS: DdlB was overexpressed in E. coli BL21 and purified by affinity chromatography. Thermal stability and structural characteristics of the purified enzyme were analyzed by circular dichroism (CD), differential scanning calorimetry and fluorescence spectroscopy. RESULTS: The stability of EcDdlB increased with proximity to its pI of 5.0, reaching the maximum at pH 5.4 with Tm and ΔHUvH U of 52.68 ºC and 484 kJ.mol-1, respectively. Deconvolutions of the CD spectra at 20 ºC showed a majority percentage of α-helix at pH 5.4 and 9.4, whereas for pH 7.4, an equal contribution of ß-structures and α-helices was calculated. Thermal denaturation process of EcDdlB proved to be irreversible with an increase in ß-structures that can contribute to the formation of protein aggregates. CONCLUSION: Such results will be useful for energy minimization of structural models aimed at virtual screening simulations, providing useful information in the search for drugs that inhibit peptidoglycan synthesis.

2,5-Diketopiperazines via Intramolecular N-Alkylation of Ugi Adducts: A Contribution to the Synthesis, Density Functional Theory Study, X-ray Characterization, and Potential Herbicide Application.

To investigate the herbicidal potential of 2,5-diketopiperazines (2,5-DKPs), we applied a known protocol to produce a series of 2,5-DKPs through intramolecular N-alkylation of Ugi adducts. However, the method was not successful for the cyclization of adducts presenting aromatic rings with some substituents at the ortho position. Results from DFT calculations showed that the presence of voluminous groups at the ortho position of a benzene ring results in destabilization of the transition structure. Lower activation enthalpies for the SN2-type cyclization of Ugi adducts were obtained when bromine, instead of a chlorine anion, is the leaving group, indicating that the activation enthalpy for the cyclization step controls the formation of the 2,5-DKP. Some Ugi adducts and 2,5-DKPs formed crystals with suitable qualities for single-crystal X-ray diffraction data collection. Phytotoxic damage of some 2,5-DKPs on leaves of the weed Euphorbia heterophylla did not differ from those caused by the commercial herbicide diquat.

PanB over-representation as part of pyrazinamide action: a proteomic insight.

Background: Pyrazinamide (PZA) represents a milestone as a first-line antituberculosis drug due to its sterilizing activity against Mycobacterium tuberculosis. Materials & Methods: The protein changes induced by subinhibitory PZA exposure of M. tuberculosis in acidic pH were evaluated by a proteomic approach. Results: Among the 1059 M. tuberculosis proteins identified, the specific acidification in the culture medium induced the over-representation of MurF (Rv2157c), and its under-representation was induced by 12 h of PZA exposure. PanB (Rv2225) was over-represented at 24 h of PZA exposure. Conclusion: The authors highlight the over-representation of PanB in M. tuberculosis correlates of PZA action in acidic pH, reinforcing the role of the pantothenate pathway as a bacillus drug target to be explored.

Use of alginate edible coating and basil (Ocimum spp) extracts on beef characteristics during storage.

The effect of alginate edible coating and the addition of two levels of basil (Ocimum spp) on polyphenols, DPPH and ABTS activities, meat characteristics (lipid oxidation, pH, weight loss, texture, and color) during storage and on consumer acceptability were evaluated. Four treatments were developed: CON (control-without coating), AEC (with alginate edible coating), B01 (with alginate edible coating + 1% of basil extract) and B02 (with alginate edible coating + 2% of basil extract). The addition of basil increased the polyphenols and antioxidant activity of meat and reduced the lipid oxidation. The pH values were not altered by the addition of basil and ageing time. The meat with coating was darker, more red and yellow. The inclusion of basil extract in the alginate-based edible coating improved meat acceptability. Thus, edible coatings with natural sources of antioxidants improve meat stability during storage and can be used in the food industry.

Metabolite profiles of energy cane and sugarcane reveal different strategies during the axillary bud outgrowth.

Commercial cultivation of sugarcane is usually carried out by planting culm segments (sett) carrying buds in their internodes. However, this is an inefficient practice due to high sprouting irregularity. In this work, we inspect the first stages of the physiological preparation of the culm for sprouting, trying to identify compounds that actively participate in this process. We compared, during the first 48 h, the metabolic profile of sugarcane against energy cane, a cultivar known to have higher sprouting speed and consistency. In fact, during this short period it was possible to observe that energy cane already had a higher physiological activity than sugarcane, with significant changes in the catabolism of amino acids, increased levels of reducing sugars, lipids and metabolic activity in the phenylpropanoid pathway. On the other hand, sugarcane samples had just begun their activity during this same period, with an increase in the level of glutamate as the most significant change, which may be linked to the strategy of these cultivars to develop their roots before leaves, opposite of what is seen for energy cane. These results contribute to the development of strategies for increasing the efficiency of sprouting in sugarcane.