Platinum(IV)-Gold(I) Agents with Promising Anticancer Activity: Selected Studies in 2D and 3D Triple-Negative Breast Cancer Models.

New heterometallic binuclear and trinuclear platinum(IV)-gold(I) compounds of the type [Pt(L)n Cl2 (OH){(OOC-4-C6 H4 -PPh2 )AuCl}x ] (L=NH3 , n=2; x=1, 2; L=diaminocyclohexane, DACH, n=1; x=2) are described. These compounds are cytotoxic and selective against a small panel of renal, bladder, ovarian, and breast cancer cell lines. We selected a trinuclear PtAu2 compound containing the PtIV core based on oxaliplatin, to further investigate its cell-death pathway, cell and organelle uptake and anticancer effects against the triple-negative breast cancer (TNBC) MDA-MB-231 cell line. This compound induces apoptosis and accumulates mainly in the nucleus and mitochondria. It also exerts remarkable antimigratory and antiangiogenic properties, and has a potent cytotoxic effect against TNBC 3D spheroids. Trinuclear compounds do not seem to display relevant interactions with calf thymus (CT) DNA and plasmid (pBR322) even in the presence of reducing agents, but inhibit pro-angiogenic enzyme thioredoxin reductase (TrxR) in TNBC cells.

ß-Cyclodextrins as affordable antivirals to treat coronavirus infection.

The SARS-CoV-2 pandemic made evident that there are only a few drugs against coronavirus. Here we aimed to identify a cost-effective antiviral with broad spectrum activity and high safety profile. Starting from a list of 116 drug candidates, we used molecular modelling tools to rank the 44 most promising inhibitors. Next, we tested their efficacy as antivirals against α and ß coronaviruses, such as the HCoV-229E and SARS-CoV-2 variants. Four drugs, OSW-1, U18666A, hydroxypropyl-ß-cyclodextrin (HßCD) and phytol, showed in vitro antiviral activity against HCoV-229E and SARS-CoV-2. The mechanism of action of these compounds was studied by transmission electron microscopy and by fusion assays measuring SARS-CoV-2 pseudoviral entry into target cells. Entry was inhibited by HßCD and U18666A, yet only HßCD inhibited SARS-CoV-2 replication in the pulmonary Calu-3 cells. Compared to the other cyclodextrins, ß-cyclodextrins were the most potent inhibitors, which interfered with viral fusion via cholesterol depletion. ß-cyclodextrins also prevented infection in a human nasal epithelium model ex vivo and had a prophylactic effect in the nasal epithelium of hamsters in vivo. All accumulated data point to ß-cyclodextrins as promising broad-spectrum antivirals against different SARS-CoV-2 variants and distant alphacoronaviruses. Given the wide use of ß-cyclodextrins for drug encapsulation and their high safety profile in humans, our results support their clinical testing as prophylactic antivirals.

Antiviral Activity of Acetylsalicylic Acid against Bunyamwera Virus in Cell Culture.

The Bunyavirales order is a large group of RNA viruses that includes important pathogens for humans, animals and plants. With high-throughput screening of clinically tested compounds we have looked for potential inhibitors of the endonuclease domain of a bunyavirus RNA polymerase. From a list of fifteen top candidates, five compounds were selected and their antiviral properties studied with Bunyamwera virus (BUNV), a prototypic bunyavirus widely used for studies about the biology of this group of viruses and to test antivirals. Four compounds (silibinin A, myricetin, L-phenylalanine and p-aminohippuric acid) showed no antiviral activity in BUNV-infected Vero cells. On the contrary, acetylsalicylic acid (ASA) efficiently inhibited BUNV infection with a half maximal inhibitory concentration (IC50) of 2.02 mM. In cell culture supernatants, ASA reduced viral titer up to three logarithmic units. A significant dose-dependent reduction of the expression levels of Gc and N viral proteins was also measured. Immunofluorescence and confocal microscopy showed that ASA protects the Golgi complex from the characteristic BUNV-induced fragmentation in Vero cells. Electron microscopy showed that ASA inhibits the assembly of Golgi-associated BUNV spherules that are the replication organelles of bunyaviruses. As a consequence, the assembly of new viral particles is also significantly reduced. Considering its availability and low cost, the potential usability of ASA to treat bunyavirus infections deserves further investigation.

ß Boswellic Acid Blocks Articular Innate Immune Responses: An In Silico and In Vitro Approach to Traditional Medicine.

Osteoarthritis (OA) is hallmarked as a silent progressive rheumatic disease of the whole joint. The accumulation of inflammatory and catabolic factors such as IL6, TNFα, and COX2 drives the OA pathophysiology into cartilage degradation, synovia inflammation, and bone destruction. There is no clinical available OA treatment. Although traditional ayurvedic medicine has been using Boswellia serrata extracts (BSE) as an antirheumatic treatment for a millennium, none of the BSE components have been clinically approved. Recently, ß boswellic acid (BBA) has been shown to reduce in vivo OA-cartilage loss through an unknown mechanism. We used computational pharmacology, proteomics, transcriptomics, and metabolomics to present solid evidence of BBA therapeutic properties in mouse and primary human OA joint cells. Specifically, BBA binds to the innate immune receptor Toll-like Receptor 4 (TLR4) complex and inhibits both TLR4 and Interleukin 1 Receptor (IL1R) signaling in OA chondrocytes, osteoblasts, and synoviocytes. Moreover, BBA inhibition of TLR4/IL1R downregulated reactive oxygen species (ROS) synthesis and MAPK p38/NFκB, NLRP3, IFNαß, TNF, and ECM-related pathways. Altogether, we present a solid bulk of evidence that BBA blocks OA innate immune responses and could be transferred into the clinic as an alimentary supplement or as a therapeutic tool after clinical trial evaluations.

When Virtual Screening Yields Inactive Drugs: Dealing with False Theoretical Friends.

The search of antivirals against SARS-CoV-2 in available libraries of compounds was initiated as soon as WHO announced that the coronavirus outbreak became a pandemic. That pivotal task has been conducted by both experimental groups in wet-labs as well as by theoretical chemists in supercomputing centers. The combination of biochemical and clinical intuitions yields first to remdesivir, a broad-spectrum antiviral that remains as the standard solution for the treatment of severe cases, while paxlovid, molnupiravir and fluvoxamine have been recently proposed as oral alternatives. Unfortunately, the intensive publication of standard virtual screening (VS) simulations might be not the best strategy to increase that short list of antivirals. This contribution joins theory and biological assays to rescore massive VS. Our goal is to critically assess pros and cons of using molecular models for drug repurposing.

Turn on Fluorescence Sensing of Zn2+ Based on Fused Isoindole-Imidazole Scaffold.

Optical chemosensors caused a revolution in the field of sensing due to their high specificity, sensitivity, and fast detection features. Imidazole derivatives have offered promising features in the literature as they bear suitable donor/acceptor groups for the selective analytes in the skeleton. In this work, an isoindole-imidazole containing a Schiff base chemosensor (1-{3-[(2-Diethylamino-ethylimino)-methyl]-2-hydroxy-5-methyl-phenyl}-2H-imidazo[5,1-a]isoindole-3,5-dione) was designed and synthesized. The complete sensing phenomena have been investigated by means of UV-Vis, fluorescence, lifetime measurement, FT-IR, NMR and ESI-MS spectroscopic techniques. The optical properties of the synthesized ligand were investigated in 3:7 HEPES buffer:DMSO medium and found to be highly selective and sensitive toward Zn2+ ion through a fluorescence turn-on response with detection limit of 0.073 µm. Furthermore, this response is effective in gel form also. The competition studies reveal that the response of the probe for Zn2+ ion is unaffected by other relevant metal ions. The stoichiometric binding study was performed utilizing Job's method which indicated a 1:1 sensor-Zn2+ ensemble. Computational calculations were performed to pinpoint the mechanism of sensing.

A Quinoxaline-Naphthaldehyde Conjugate for Colorimetric Determination of Copper Ion.

This work facilitates detection of bivalent copper ion by a simple Schiff base probe QNH based on a quinoxaline-naphthaldehyde framework. The detailed study in absorption spectroscopy and theoretical aspects and crystal study of the probe and probe-copper complex has been discussed. The detection limit of the probe in the presence of Cu2+ is 0.45 µM in HEPES-buffer/acetonitrile (3/7, v/v) medium for absorption study. The reversibility of the probe-copper complex has been investigated by EDTA. The selective visual detection of copper has been established also in gel form.

Intercalation Ability of Novel Monofunctional Platinum Anticancer Drugs: A Key Step in Their Biological Action.

Phenanthriplatin (PtPPH) is a monovalent platinum(II)-based complex with a large cytotoxicity against cancer cells. Although the aqua-activated drug has been assumed to be the precursor for DNA damage, it is still under debate whether the way in which that metallodrug attacks to DNA is dominated by a direct binding to a guanine base or rather by an intercalated intermediate product. Aiming to capture the mechanism of action of PtPPH, the present contribution used theoretical tools to systematically assess the sequence of all possible mechanisms on drug activation and reactivity, for example, hydrolysis, intercalation, and covalent damage to DNA. Ab initio quantum mechanical (QM) methods, hybrid QM/QM' schemes, and independent gradient model approaches are implemented in an unbiased protocol. The performed simulations show that the cascade of reactions is articulated in three well-defined stages: (i) an early and fast intercalation of the complex between the DNA bases, (ii) a subsequent hydrolysis reaction that leads to the aqua-activated form, and (iii) a final formation of the covalent bond between PtPPH and DNA at a guanine site. The permanent damage to DNA is consequently driven by that latter bond to DNA but with a simultaneous π-π intercalation of the phenanthridine into nucleobases. The impact of the DNA sequence and the lateral backbone was also discussed to provide a more complete picture of the forces that anchor the drug into the double helix.

Using Theory To Extend the Scope of Azobenzene Drugs in Chemotherapy: Novel Combinations for a Specific Delivery.

Gut microorganisms metabolize azobenzene compounds (Ph1 -N=N-Ph2 ) into free aniline products (Ph1 -NH2 +H2 N-Ph2 ), a process that has been largely investigated to reduce dyes residues in the textile industry. However, the action of bacterial core enzymes such as azoreductases (AzoR) might also help to deliver prodrugs that become active when they reach the colonic region, a mechanism with potential applications for the treatment of inflammatory bowel disease (IBD) and colorectal cancer. So far, three azo-bonded prodrugs of 5-aminosalicylic acid (5-ASA), for example, sulfasalazine, olsalazine and balsalazide, have been used for colon-targeted delivery. The present contribution describes the first rational design of a novel azobenzene prodrug thanks to a computational approach, with a focus on linking 5-ASA to another approved anti-inflammatory drug. The resulting prodrugs were assessed for their degradation upon AzoR action. Replacing the original carriers by irsogladine is found to improve action.

Addendum: MCC950 closes the active conformation of NLRP3 to an inactive state.

An Addendum to this paper has been published: https://doi.org/10.1038/s41589-021-00741-6.

Norditerpenoids with Selective Anti-Cholinesterase Activity from the Roots of Perovskia atriplicifolia Benth.

Inhibition of cholinesterases remains one of a few available treatment strategies for neurodegenerative dementias such as Alzheimer's disease and related conditions. The current study was inspired by previous data on anticholinesterase properties of diterpenoids from Perovskia atriplicifolia and other Lamiaceae species. The acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition by the three new natural compounds-(1R,15R)-1-acetoxycryptotanshinone (1), (1R)-1-acetoxytanshinone IIA (2), and (15R)-1-oxoaegyptinone A (3)-as well as, new for this genus, isograndifoliol (4) were assessed. Three of these compounds exhibited profound inhibition of butyrylcholinesterase (BChE) and much weaker inhibition of acetylcholinesterase (AChE). All compounds (1-4) selectively inhibited BChE (IC50 = 2.4, 7.9, 50.8, and 0.9 µM, respectively), whereas only compounds 3 and 4 moderately inhibited AChE (IC50 329.8 µM and 342.9 µM). Molecular docking and in silico toxicology prediction studies were also performed on the active compounds. Natural oxygenated norditerpenoids from the traditional Central Asian medicinal plant P. atriplicifolia are selective BChE inhibitors. Their high potential makes them useful candidate molecules for further investigation as lead compounds in the development of a natural drug against dementia caused by neurodegenerative diseases.

MCC950 closes the active conformation of NLRP3 to an inactive state.

NLRP3 (NOD-like receptor pyrin domain-containing protein 3) is an innate immune sensor that contributes to the development of different diseases, including monogenic autoinflammatory syndromes, gout, atherosclerosis, and Alzheimer's disease. The molecule sulfonylurea MCC950 is a NLRP3 inflammasome inhibitor with potential clinical utility. However, the mechanism of action of MCC950 remains unknown. Here, we characterize the mechanism of action of MCC950 in both wild-type and autoinflammatory-related NLRP3 mutants, and demonstrate that MCC950 closes the 'open' conformation of active NLRP3.

BRUSELAS: HPC Generic and Customizable Software Architecture for 3D Ligand-Based Virtual Screening of Large Molecular Databases.

BRUSELAS (balanced rapid and unrestricted server for extensive ligand-aimed screening) is a novel, highly efficient web software architecture for 3D shape and pharmacophore searches in off the cuff libraries. A wide panel of shape and pharmacophore similarity algorithms are combined to avoid unbiased results while yielding consensus scoring functions. To evaluate its reliability, BRUSELAS was tested against other similar servers (e.g., USR-VS, SwissSimilarity, ChemMapper) to search for potential antidiabetic drugs. A web tool is developed for users to customize their tasks and is accessible free of any charge or login at http://bio-hpc.eu/software/Bruselas . Source code is available on request.

Profiling Auspicious Butyrylcholinesterase Inhibitory Activity of Two Herbal Molecules: Hyperforin and Hyuganin C.

Cholinergic therapy based on cholinesterase (ChE) inhibitory drugs is the mainstay for the treatment of Alzheimer's disease. Therefore, an extensive research has been continuing for the discovery of drug candidates as inhibitors of acetyl- and butyrylcholinesterase. In this study, two natural molecules, e. g. hyperforin and hyuganin C were tested in vitro for their AChE and BChE inhibitory activity. Both of the compounds were ineffective against AChE, whereas hyperforin (IC50 =141.60±3.39 µm) and hyuganin C (IC50 =38.86±1.69 µm) were found to be the highly active inhibitors of BChE as compared to galantamine (IC50 =46.58±0.91 µm) which was used as the reference. Then, these molecules were further proceeded to molecular docking experiments in order to establish their interactions at the active site of BChE. The molecular docking results indicated that both of them are able to block the access to key residues in the catalytic triad of the enzyme, while they complement some of the hydrophobic residues of the cavity, what is consistent with our in vitro data. While both compounds were predicted as mutagenic, only hyuganin C showed hepatotoxicity in in silico analysis. According to whole outcomes that we obtained, particularly hyuganin C besides hyperforin are the promising BChE inhibitors, which can be the promising compounds for AD therapy.

A review of ligand-based virtual screening web tools and screening algorithms in large molecular databases in the age of big data.

Virtual screening has become a widely used technique for helping in drug discovery processes. The key to this success is its ability to aid in the identification of novel bioactive compounds by screening large molecular databases. Several web servers have emerged in the last few years supplying platforms to guide users in screening publicly accessible chemical databases in a reasonable time. In this review, we discuss a representative set of online virtual screening servers and their underlying similarity algorithms. Other related topics, such as molecular representation or freely accessible databases are also treated. The most relevant contributions to this review arise from critical discussions concerning the pros and cons of servers and algorithms, and the challenges that future works must solve in a virtual screening framework.

Using Theory To Reinterpret the Kinetics of Monofunctional Platinum Anticancer Drugs: Stacking Matters.

The monofunctional platinum drug phenanthriplatin (phenPt) blocks the replication of cancer cells even if it reacts with only one guanine base. However, there is still insufficient experimental data to improve its cytotoxicity and all previously proposed chemical modifications of the parent structure have resulted in a loss of activity. We use theoretical tools to illustrate the key steps in the biological mechanisms of phenPt; that is, its activation in water and the subsequent attack on DNA. Our simulations suggest that the measured kinetic parameters, which are based on free nucleobases in solution, need to be reinterpreted because the self-assembled stacked reactive adduct formed in the reaction is inaccessible in real DNA. The constants reported here will help guide future work in the synthesis of anticancer platinum drugs.

Evaluation of butyrylcholinesterase inhibitory activity by chlorogenic acids and coffee extracts assed in ITC and docking simulation models.

In patients with Alzheimer's disease (AD), elevated levels of butyrylcholinesterase (BChE) are observed. The enzyme hydrolyses acetylcholine, which shows deficiency in these patients. Therefore, BChE inhibitors are used in the treatment of Alzheimer's disease, especially synthetic ones, showing side effects with long-term intake. The sources of natural BChE inhibitors are constantly being sought. Coffee brews have been shown to reduce the symptoms of AD in epidemiological studies. However, the ability to inhibit BChE activity has not been investigated, depending on the degree of coffee roasting. The study was aimed at determining the interactions between BChE and the bioactive compounds of coffee and their ability to inhibit the activity of BChE. A comparison of individual bioactive compounds of coffee as well as extracts obtained from two main species, Arabica and Robusta, and additionally from different degrees of roasting was made. Two models were used: isothermal titration calorimetry (ITC) and molecular docking simulation. ITC analysis showed strong interactions of ferulic and dihydrocaffeic acids with BChE. These compounds are the metabolites of the chlorogenic acids, including both mono- and diesters of caffeic acid with quinic acid. Docking simulation showed their strong hydrophobic interaction with BChE, stabilized by hydrogen bonds and pi-pi interactions. After introducing acetylcholine into the model system, the strongest ability to inhibit hydrolytic activity of BChE was again observed for ferulic acid and additionally for 3-caffeoylquinic acid, and among coffee brews the most active were light roasted Arabica and green Robusta. The study was based on the physiological concentrations of coffee components, so the potential therapeutic effect of coffee infusions was proved.

Evaluation of estrogenic activity of red clover (Trifolium pratense L.) sprouts cultivated under different conditions by content of isoflavones, calorimetric study and molecular modelling.

Isoflavones have an affinity for estrogen receptors (ERs) including beneficial affinity for ERß. Widely used soy is a source of poorly absorbed isoflavones glycosides. Red clover contains mostly easily absorbed free aglycones. Red clover sprouts were cultivated under different conditions (white light, UVA or UVB for 12 or 24 h a day at 18 or 25 °C) to maximise the content of isoflavones, especially of high affinity for ERß. The affinity of isoflavones to ERs was evaluated by molecular modelling and isothermal titration calorimetry (ITC). The richest source of isoflavones, especially formononetin were sprouts cultivated for 10 days under continuous white light and at 25 °C (562 mg/100 g of fresh mass). Formononetin and the above sprouts has been shown to have a high affinity for ERß. Red clover sprouts can be considered as a source of phytoestrogens with high biological activity and as a dietary supplement reducing menopausal symptoms.

Sedative and muscle relaxant activities of diterpenoids from Phlomidoschema parviflorum

Abstract Phlomidoschema parviflorum (Benth.) Vved. (Basionym: Stachys parviflora Benth.) Lamiaceae, have significance medicinal importance as it is used in number of health disorders including diarrhea, fever, sore mouth and throat, internal bleeding, weaknesses of the liver and heart genital tumors, sclerosis of the spleen, inflammatory tumors and cancerous ulcers. The present contribution deals with the sedative and muscle relaxant like effects of diterpenoids trivially named stachysrosane and stachysrosane, isolated from the ethyl acetate soluble fraction of P. parviflorum. Both compounds (at 5, 10 and 15 mg/kg, i.p) were assessed for their in vivo sedative and muscle relaxant activity in open field and inclined plane test, respectively. The geometries of both compounds were optimized with density functional theory. The molecular docking of both compounds were performed with receptor gamma aminobutyric acid. Both compounds showed marked activity in a dose dependent manner. The docking studies showed that both compounds interact strongly with important residues in receptor gamma aminobutyric acid. The reported data demonstrate that both compounds exhibited significant sedative and muscle relaxant-like effects in animal models, which opens a door for novel therapeutic applications.