Antarctic fungi produce pigment with antimicrobial and antiparasitic activities.

Natural pigments have received special attention from the market and industry as they could overcome the harm to health and the environmental issues caused by synthetic pigments. These pigments are commonly extracted from a wide range of organisms, and when added to products they can alter/add new physical-chemical or biological properties to them. Fungi from extreme environments showed to be a promising source in the search for biomolecules with antimicrobial and antiparasitic potential. This study aimed to isolate fungi from Antarctic soils and screen them for pigment production with antimicrobial and antiparasitic potential, together with other previously isolated strains A total of 52 fungi were isolated from soils in front of the Collins Glacier (Southeast border). Also, 106 filamentous fungi previously isolated from the Collins Glacier (West border) were screened for extracellular pigment production. Five strains were able to produce extracellular pigments and were identified by ITS sequencing as Talaromyces cnidii, Pseudogymnoascus shaanxiensis and Pseudogymnoascus sp. All Pseudogymnoascus spp. (SC04.P3, SC3.P3, SC122.P3 and ACF093) extracts were able to inhibit S. aureus ATCC6538 and two (SC12.P3, SC32.P3) presented activity against Leishmania (L.) infantum, Leishmania amazonensis and Trypanossoma cruzii. Extracts compounds characterization by UPLC-ESI-QToF analysis confirmed the presence of molecules with biological activity such as: Asterric acid, Violaceol, Mollicellin, Psegynamide A, Diorcinol, Thailandolide A. In conclusion, this work showed the potential of Antartic fungal strains from Collins Glacier for bioactive molecules production with activity against Gram positive bacteria and parasitic protozoas.

Inhibitory effects of 190 compounds against SARS-CoV-2 Mpr o protein: Molecular docking interactions.

COVID-19 has caused many deaths since the first outbreak in 2019. The burden on healthcare systems around the world has been reduced by the success of vaccines. However, population adherence and the occurrence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants are still challenging tasks to be affronted. In addition, the newly approved drug presents some limitations in terms of side effects and drug interference, highlighting the importance of searching for new antiviral agents against SARS-CoV-2. The SARS-CoV-2 main protease (Mpr o ) represents a versatile target to search for new drug candidates due to its essential role in proteolytic activities responsible for the virus replication. In this work, a series of 190 compounds, composed of 27 natural ones and 163 synthetic compounds, were screened in vitro for their inhibitory effects against SARS-CoV-2 Mpro . Twenty-five compounds inhibited Mpro with inhibitory constant values (Ki ) between 23.2 and 241 µM. Among them, a thiosemicarbazone derivative was the most active compound. Molecular docking studies using Protein Data Bank ID 5RG1, 5RG2, and 5RG3 crystal structures of Mpro revealed important interactions identified as hydrophobic, hydrogen bonding and steric interactions with amino acid residues in the active site cavity. Overall, our findings indicate the described thiosemicarbazones as good candidates to be further explored to develop antiviral leads against SARS-CoV-2. Moreover, the studies showed the importance of careful evaluation of test results to detect and exclude false-positive findings.

Studies of Cytotoxicity Effects, SARS-CoV-2 Main Protease Inhibition, and in Silico Interactions of Synthetic Chalcones.

SARS-CoV-2 main protease (Mpro ) plays an essential role in proteolysis cleavage that promotes coronavirus replication. Thus, attenuating the activity of this enzyme represents a strategy to develop antiviral agents. We report inhibitory effects against Mpro of 40 synthetic chalcones, and cytotoxicity activities, hemolysis, and in silico interactions of active compounds. Seven of them bearing a (E)-3-(furan-2-yl)-1-arylprop-2-en-1-one skeleton (10, 28, and 35-39) showed enzyme inhibition with IC50 ranging from 13.76 and 36.13 µM. Except for 35 and 36, other active compounds were not cytotoxic up to 150 µM against THP-1 and Vero cell lines. Compounds 10, and 35-39 showed no hemolysis while 28 was weakly hemotoxic at 150 µM. Moreover, molecular docking showed interactions between compound 10 and Mpro (PDBID 5RG2 and 5RG3) with proximity to cys145 and His41, suggesting a covalent binding. Products of the reaction between chalcones and cyclohexanethiol indicated that this binding could be a Michael addition type.

The Antinociceptive Effect of a Hydroalcoholic Extract of Polygala altomontana and Its Chemical Profile Using UPLC-ESI-QTOF-HR-MS.

The hydroalcoholic extract of Polygala altomontana (30, 100, and 300 mg/kg, i.g.) showed a dose-dependent antinociceptive action during the inflammatory phase of the formalin test. In addition, the preparation (30 and 300 mg/kg, i.g.) showed anti-hyperalgesic action when tested on a mechanical nociception model. UPLC-ESI-QTOF-MS data indicated the active extract contained phenylpropanoid sucrose esters, glycosylated quercetin derivatives, styrylpyrones, and coumarins. Some identified compounds, including styrylpyrones and coumarins, have previously demonstrated antinociceptive action. The results also show that P. altomontana shows potential for developing pain-relieving herbal remedies and drugs.

Pyrazolines as potential anti-Alzheimer's agents: DFT, molecular docking, enzyme inhibition and pharmacokinetic studies.

Alzheimer's disease (AD) is a neurodegenerative disease that is characterized as the main dementia in the elderly. Eighteen pyrazolines were synthesized and evaluated for their inhibitory effects against acetylcholinesterase (AChE) in vitro. Possible interactions between pyrazolines and the enzyme were explored by in silico experiments. Compound 2B of the series was the most active pyrazoline with an IC50 value of 58 nM. Molecular docking studies revealed two important π-π interactions with residues Trp 286 and Tyr 341. A correlation between the HOMO-1 surface and AChE inhibition was observed. ADMET assays demonstrated a good profile for compound 2B. From the abovementioned findings, a new avenue of compound 2B analogues could be explored to develop anti-AD agents.

Characterization of Planktochlorella nurekis Extracts and Virucidal Activity against a Coronavirus Model, the Murine Coronavirus 3.

Certain members of the Coronaviridae family have emerged as zoonotic agents and have recently caused severe respiratory diseases in humans and animals, such as SARS, MERS, and, more recently, COVID-19. Antivirals (drugs and antiseptics) capable of controlling viruses at the site of infection are scarce. Microalgae from the Chlorellaceae family are sources of bioactive compounds with antioxidant, antiviral, and antitumor activity. In the present study, we aimed to evaluate various extracts from Planktochlorella nurekis in vitro against murine coronavirus-3 (MHV-3), which is an essential human coronavirus surrogate for laboratory assays. Methanol, hexane, and dichloromethane extracts of P. nurekis were tested in cells infected with MHV-3, and characterized by UV-vis spectrophotometry, nuclear magnetic resonance (NMR) spectroscopy, ultraperformance liquid chromatography-mass spectrometry (UPLC-MS), and the application of chemometrics through principal component analysis (PCA). All the extracts were highly efficient against MHV-3 (more than a 6 Log unit reduction), regardless of the solvent used or the concentration of the extract, but the dichloromethane extract was the most effective. Chemical characterization by spectrophotometry and NMR, with the aid of statistical analysis, showed that polyphenols, carbohydrates, and isoprene derivatives, such as terpenes and carotenoids have a more significant impact on the virucidal potential. Compounds identified by UPLC-MS were mainly lipids and only found in the dichloromethane extract. These results open new biotechnological possibilities to explore the biomass of P. nurekis; it is a natural extract and shows low cytotoxicity and an excellent antiviral effect, with low production costs, highlighting a promising potential for development and implementation of therapies against coronaviruses, such as SARS-CoV-2.

Anti-inflammatory and anti-aggregating effects of rangpur in the first trimester of growth: ultra-performance liquid chromatography-electrospray mass spectrometry profile and quantification of hesperidin.

BACKGROUND: Citrus fruits are a rich source of valuable molecules, and their industrial processing produces bagasses, little explored to generate important by-products. These Citrus residues, including seeds and peels, also contain numerous pharmacologically important substances. To reduce the impact of these Citrus by-products, young, harvested fruits could be used as a functional supplemental food while another part is grown until maturity for industrial production. This study therefore aims to valorize rangpur (Citrus limonia) in the first 3 months of its growth by investigating and comparing its monthly chemical profiles using ultra-performance liquid chromatography-electrospray mass spectrometry (UPLC-ESI-MS) and its anti-inflammatory and antiplatelet activity. RESULTS: Extracts obtained from the fruits harvested in November, December, and January, 2017 and 2018 (L221117, L161217, and L160118) showed different UPLC-ESI-MS profiles. Twenty-five of the 26 detected metabolites were identified as cyclitol, pyrrolidine betaine, aryl propanoyl esters, chlorogenic acids, flavonoids, coumarins, and limonoids. Quantification studies indicated an increased concentration of hesperidin from the younger fruits to the older fruits of the series. L160118 reduced nitrogen oxide (NOx), tumor necrosis factor alpha (TNF-α), and interleukin 6 (IL-6) levels more than other extracts. Their activity followed the same trends as the hesperidin concentration in each fruit. In contrast, the most promising antiplatelet activity was observed with the extracts from the two youngest fruits. This suggests combined effects of the chemical components found in these fruits' extracts. CONCLUSION: The extracts obtained from these young fruits showed considerable anti-inflammatory and antiplatelet activity. Overall, young rangpur could be used as raw material to produce functional foods without producing any waste. © 2022 Society of Chemical Industry.

Essential oils from leaves of Vernonanthura montevidensis (Spreng.) H. Rob.: chemical profile and antimollicute potential.

Aiming to valorise the Atlantic Rainforest biodiversity in Santa Catarina, the chemical characterisation of the essential oils (EOs) from leaves of Vernonanthura montevidensis (Spreng.) H. Rob. is described for the first time. Fresh leaves collected in the year 2014 and 2015, were submitted to hydrodistillation to give pale blue EOs in yields of 0.21 and 0.19%, respectively. The EOs were characterised by GC-MS and GC-FID semi- and quantitative methods. The monoterpene ß-pinene was the major constituent in both samples reaching a maximum of 26.3%. The monoterpene α-pinene and the sesquiterpene ß-caryophyllene, were also among the major constituents in both samples. By means of the extracted ion chromatogram procedure, it was possible to detect chamazulene, which was associated with the pale blue colour of the essential oils. In the in vitro antimollicute assays, the essential oil was moderately active against Mycoplasma genitalium and M. pneumoniae with MIC values of 250 µg mL-1.

Natural Products with Tandem Anti-inflammatory, Immunomodulatory and Anti-SARS-CoV/2 Effects: A Drug Discovery Perspective against SARS-CoV-2.

BACKGROUND: COVID-19 is still causing long-term health consequences, mass deaths, and collapsing healthcare systems around the world. There are no efficient drugs for its treatment. However, previous studies revealed that SARS-CoV-2 and SARS-CoV have 96% and 86.5% similarities in cysteine proteases (3CLpro) and papain-like protease (PLpro) sequences, respectively. This resemblance could be important in the search for drug candidates with antiviral effects against SARS-CoV-2. OBJECTIVE: This paper is a compilation of natural products that inhibit SARS-CoV 3CLpro and PLpro and, concomitantly, reduce inflammation and/or modulate the immune system as a perspective strategy for COVID-19 drug discovery. It also presents in silico studies performed on these selected natural products using SARS-CoV-2 3CLpro and PLpro as targets to propose a list of hit compounds. METHODS: The plant metabolites were selected in the literature based on their biological activities on SARS-CoV proteins, inflammatory mediators, and immune response. The consensus docking analysis was performed using four different packages. RESULTS: Seventy-nine compounds reported in the literature with inhibitory effects on SARS-CoV proteins were reported as anti-inflammatory agents. Fourteen of them showed immunomodulatory effects in previous studies. Five and six of these compounds showed significant in silico consensus as drug candidates that can inhibit PLpro and 3CLpro, respectively. Our findings corroborated recent results reported on anti-SARS-CoV-2 in the literature. CONCLUSION: This study revealed that amentoflavone, rubranoside B, savinin, psoralidin, hirsutenone, and papyriflavonol A are good drug candidates for the search of antibiotics against COVID-19.

Cell Cycle Arrest and Apoptosis Induction by a New 2,4-Dinitrobenzenesulfonamide Derivative In Acute Leukemia Cells.

BACKGROUND: Current therapies for acute leukemias (ALs) are associated with severe adverse reactions and high relapse rates, which makes the search for new antileukemic agents a necessity. Therefore, the aim of this study was to evaluate the effects of a new sulfonamide, S1, in AL cells K562 and Jurkat. METHODS: The cytotoxic activity of S1 was assessed using MTT method. The involvement of apoptosis in the mechanism of cell death was assessed by flow cytometry and fluorescence microscopy. RESULTS: Our results demonstrated that S1 induced morphological changes suggestive of apoptosis in both K562 and Jurkat cells. Additionally, S1 was not cytotoxic to normal erythrocytes and mononuclear cells and had a highly selective cytotoxicity for AL lineages. The mechanisms of cell death induced by S1 in K562 cells involves cell cycle arrest at G2/M phase and the activation of both extrinsic and intrinsic apoptosis, with an increased FasR and AIF expression and the loss of mitochondrial potential. As for Jurkat, we observed cell cycle blockade at G0/G1 phase, phosphatidylserine exposure and the involvement of intrinsic apoptosis only, with mitochondrial potential loss and a reduced expression of Survivin.  Although sulfonamide S1 did not altered Bcl-2 and Bax expression in AL cell lines, it was able to activate caspase-3 in K562 cells. CONCLUSION: Our results suggest that sulfonamide S1 may be a promising candidate for the development of new drugs for the treatment of ALs.

Polygala sabulosa A.W. Bennett extract mitigates motor and cognitive deficits in a mouse model of acute ischemia.

Stroke is considered one of the leading causes of death worldwide. The treatment is limited; however, the Brazilian flora has a great source of natural products with therapeutic potentials. Studies with the medicinal plant Polygala sabulosa W. Bennett provided evidence for its use as an anti-inflammatory and neuroprotective drug. In the case of ischemic stroke due to lack of oxygen, both acute and chronic inflammatory processes are activated. Thus, we hypothesized that P. sabulosa (HEPs) has the potential to treat the motor and cognitive deficits generated by ischemic stroke. Male mice were subjected to global ischemia for 60 min, followed by reperfusion and orally treated with HEPs (100 mg/kg in saline + 3% tween 20) twice a day (12 h apart) for 48 h starting 3 h after surgery. Motor skills were assessed using grip force and open field tasks. Hippocampi were then collected for mRNA quantification of the cytokines IL-1-ß and TNF-α levels. After 48 h of acute treatment, spatial reference memory was evaluated in a Morris water maze test for another group of animals. We show that HEPs treatment significantly prevented motor weakness induced by ischemia. Brain infarct area was reduced by 22.25% with downregulation of the levels of IL-1ß and TNF-α mRNA. Learning performance and memory ability on Morris water maze task were similar to the sham group. Our data demonstrates the neuroprotective properties of HEPs through its anti-inflammatory activities, which prevent motor and cognitive impairments, suggesting that HEPs may be an effective therapy for ischemic stroke.

Antioxidant and anti-inflammatory action (in vivo and in vitro) from the trunk barks of Cabreúva (Myrocarpus frondosus Allemao, Fabaceae).

ETHNOPHARMACOLOGICAL RELEVANCE: Myrocarpus frondosus, known as cabreúva, is a tree whose trunk barks are used in folk medicine as tea, syrup, ointments, and tinctures for the treatment of inflammation. However, there is no scientific evidence demonstrating this activity. AIM OF THE STUDY: The present investigation was focused on evaluating the antioxidant and anti-inflammatory activities of M. frondosus, using the in vitro model of RAW 264.7 macrophages induced by LPS and the in vivo model of mouse pleurisy induced by carrageenan. MATERIALS AND METHODS: M. frondosus trunk barks were dried at room temperature for seven days and subjected to exhaustive maceration with ethanol (70%) to obtain its crude extract (CE). CE was subjected to UPLC-HRMS analysis to establish its chemical profile. Its antioxidant activity was evaluated using the DPPH method, reducing power by the iron (III) to iron (II) reduction assay and the ß-carotene-linoleic acid bleaching assay. The RAW 264.7 macrophages were pretreated with the CE in a non-cytotoxic concentration and induced by LPS (1 µg/mL). After 24 h, using the supernatant, we evaluated the nitric oxide (NOx) and interleukin-6 (IL-6) levels. The anti-inflammatory effects of CE (at doses of 30, 100 and 300 mg/kg) were evaluated on leukocyte migration (total and differential), exudate concentrations, myeloperoxidase (MPO) and adenosine-deaminase (ADA) activities, NOx, tumor necrosis factor-α (TNF-α), and IL-6 levels, by using a murine model of neutrophilic inflammation. RESULTS: The UPLC-HRMS of CE revealed the presence of isoflavonones, including biochanin A and formononetin. CE exhibited good antioxidant activity by quenching and decreasing free radicals, as well as reducing pro-oxidant metals. CE did not show cytotoxicity at a concentration below 11 µg/mL and reduced the secretion of the pro-inflammatory NOx in the inflamed macrophages. In vivo assay revealed that CE caused a pronounced inhibition on leukocyte migration, and this inhibition was due to its ability to reduce neutrophil migration. Moreover, CE was also able to reduce the release of critical pro-inflammatory mediators such as MPO, NOx, TNF-α, and IL-6. CONCLUSIONS: All these findings indicate that M. frondosus exhibited antioxidant activity and anti-inflammatory effect.

A chalcone derivative binds a putative allosteric site of YopH: Inhibition of a virulence factor of Yersinia.

Identification of allosteric inhibitors of PTPs has attracted great interest as a new strategy to overcome the challenge of discover potent and selective molecules for therapeutic intervention. YopH is a virulence factor of the genus Yersinia, validated as an antimicrobial target. The finding of a second substrate binding site in YopH has revealed a putative allosteric site that could be further exploited. Novel chalcone compounds that inhibit PTPs activity were designed and synthesized. Compound 3j was the most potent inhibitor, interestingly, with different mechanisms of inhibition for the panel of enzymes evaluated. Further, our results showed that compound 3j is an irreversible non-competitive inhibitor of YopH that binds to a site different than the catalytic site, but close to the well-known second binding site of YopH.

Psychopharmacological effects and safety of styryl-2-pyrones and dihydrostyryl-2-pyrones-rich fraction from Polygala sabulosa: absence of withdrawal syndrome and tolerance to anxiolytic-like and anticonvulsant effects.

OBJECTIVES: To investigate whether mice develop tolerance to the anxiolytic-like and anticonvulsant effects of subchronic treatment with EA (the styryl-2-pyrones and dihydrostyryl-2-pyrones-rich fraction of Polygala sabulosa), as well as any withdrawal symptoms after abrupt discontinuation; to compare the effects of EA with those of diazepam (DZP) on withdrawal-induced anxiety; and to evaluate the toxicity of EA according to OECD guidelines. METHODS: Male or female mice were acutely or subchronically treated with EA or DZP, and their tolerance to anxiolytic (evaluated in the elevated plus maze, EPM) and anticonvulsant effects (measured against pentylenetetrazole (PTZ)-induced convulsions) were investigated. Other groups received EA or DZP for 28 days followed by withdrawal, being the anxiety-like behaviour evaluated in the EPM. KEY FINDINGS: Both acute and subchronic treatments with EA induced an anxiolytic effect in the EPM. The anticonvulsant activity of DZP, but not EA, was reduced by protracted treatment. EA withdrawal retained the anxiolytic profile, while DZP withdrawal induced anxiogenesis. EA counteracted the anxiogenic-like actions of DZP withdrawal. EA has low toxicity as it did not cause any changes in the biochemical, haematological and histopathological markers. CONCLUSIONS: EA avoids the development of tolerance to its anxiolytic-like and anticonvulsant actions, and does not promote withdrawal syndrome. EA does not cause relevant toxic effects in rodents.