Learning Strategies from Nature's Blueprint to Cyclic Carbonate Synthesis.

Nature is a remarkable source of inspiration for developing sustainable and eco-friendly synthetic procedures. In recent years, the synthesis of cyclic carbonates has garnered significant attention due to their versatile applications in various fields, including materials science, pharmaceuticals, and green chemistry. Drawing inspiration from nature, researchers have explored innovative synthetic routes that mimic biological processes to produce cyclic carbonates efficiently and sustainably. This article reviews nature-inspired synthetic procedures for cyclic carbonate formation, highlighting the key strategies and principles employed. Through biomimicry, researchers aim to harness the efficiency and selectivity observed in biological systems to develop greener and more sustainable methods for cyclic carbonate synthesis. Integrating bio-inspired strategies offers opportunities for improving synthetic efficiency and contributes to reducing the environmental impact associated with traditional chemical processes. This review underscores the potential of nature-inspired approaches in advancing the field of cyclic carbonate synthesis toward more sustainable and environmentally benign practices, focusing on recent literature.

Polyvinylimidazole-Based Cryogel as an Efficient Tool for the Capture and Release of Oleuropein in Aqueous Media.

A polyvinylimidazole-based cryogel is presented as a pioneering solution for efficient extraction and release of partially water-soluble polyphenols from olive byproducts. Specifically, oleuropein was used as model molecule to evaluate its recovery from water. The material merges the properties of interconnected cryogel structure in adsorbing molecules via fast diffusion flux, with the strong electrostatic interactions acted by imidazole moiety. Such cryogel achieves effective oleuropein binding likely through hydrogen bonding and π-π interactions. Comprehensive assessments of static adsorption kinetics, isotherms, and desorption kinetics underscore the cryogel's efficacy in oleuropein extraction and release, highlighting its pivotal role in valorizing olive wastewater through sustainable biotechnological applications.

Tetrazine-trans-cyclooctene ligation: Unveiling the chemistry and applications within the human body.

Bioorthogonal reactions have revolutionized chemical biology by enabling selective chemical transformations within living organisms and cells. This review comprehensively explores bioorthogonal chemistry, emphasizing inverse-electron-demand Diels-Alder (IEDDA) reactions between tetrazines and strained dienophiles and their crucial role in chemical biology and various applications within the human body. This highly reactive and selective reaction finds diverse applications, including cleaving antibody-drug conjugates, prodrugs, proteins, peptide antigens, and enzyme substrates. The versatility extends to hydrogel chemistry, which is crucial for biomedical applications, yet it faces challenges in achieving precise cellularization. In situ activation of cytotoxic compounds from injectable biopolymer belongs to the click-activated protodrugs against cancer (CAPAC) platform, an innovative approach to tumor-targeted prodrug delivery and activation. The CAPAC platform, relying on click chemistry between trans-cyclooctene (TCO) and tetrazine-modified biopolymers, exhibits modularity across diverse tumor characteristics, presenting a promising approach in anticancer therapeutics. The review highlights the importance of bioorthogonal reactions in developing radiopharmaceuticals for positron emission tomography (PET) imaging and theranostics, offering a promising avenue for diverse therapeutic applications.

Synthesis, Characterisation, and In Vitro Evaluation of Biocompatibility, Antibacterial and Antitumor Activity of Imidazolium Ionic Liquids.

In recent decades, ionic liquids (ILs) have garnered research interest for their noteworthy properties, such as thermal stability, low or no flammability, and negligible vapour pressure. Moreover, their tunability offers limitless opportunities to design ILs with properties suitable for applications in many industrial fields. This study aims to synthetise two series of methylimidazolium ILs bearing long alkyl chain in their cations (C9, C10, C12, C14, C16, C18, C20) and with tetrafluoroborate (BF4) and the 1,3-dimethyl-5-sulfoisophthalate (DMSIP) as counter ions. The ILs were characterised using 1H-NMR and MALDI-TOF, and their thermal behaviour was investigated through DSC and TGA. Additionally, the antimicrobial, anticancer, and cytotoxic activities of the ILs were analysed. Moreover, the most promising ILs were incorporated at different concentrations (0.5, 1, 5 wt%) into polyvinyl chloride (PVC) by solvent casting to obtain antimicrobial blend films. The thermal properties and stability of the resulting PVC/IL films, along with their hydrophobicity/hydrophilicity, IL surface distribution, and release, were studied using DSC and TGA, contact angle (CA), SEM, and UV-vis spectrometry, respectively. Furthermore, the antimicrobial and cytotoxic properties of blends were analysed. The in vitro results demonstrated that the antimicrobial and antitumor activities of pure ILs against t Listeria monocytogenes, Escherichia coli, Pseudomonas fluorescens strains, and the breast cancer cell line (MCF7), respectively, were mainly dependent on their structure. These activities were higher in the series containing the BF4 anion and increased with the increase in the methylimidazolium cation alkyl chain length. However, the elongation of the alkyl chain beyond C16 induced a decrease in antimicrobial activity, indicating a cut-off effect. A similar trend was also observed in terms of in vitro biocompatibility. The loading of both the series of ILs into the PVC matrix did not affect the thermal stability of PVC blend films. However, their Tonset decreased with increased IL concentration and alkyl chain length. Similarly, both the series of PVC/IL films became more hydrophilic with increasing IL concentration and alkyl chain. The loading of ILs at 5% concentration led to considerable IL accumulation on the blend film surfaces (as observed in SEM images) and, subsequently, their higher release. The biocompatibility assessment with healthy human dermal fibroblast (HDF) cells and the investigation of antitumoral properties unveiled promising pharmacological characteristics. These findings provide strong support for the potential utilisation of ILs in biomedical applications, especially in the context of cancer therapy and as antibacterial agents to address the challenge of antibiotic resistance. Furthermore, the unique properties of the PVC/IL films make them versatile materials for advancing healthcare technologies, from drug delivery to tissue engineering and antimicrobial coatings to diagnostic devices.

TiO2/Loofah-Halloysite Bio-Hybrid Composites as Efficient Systems for VOCs Removal.

Volatile organic compounds (VOCs), recognized as hazardous air contaminants, prompt the exploration of sustainable air purification methods. Solar photocatalytic oxidation emerges as a promising solution, utilizing semiconductor photocatalysts like titanium dioxide (TiO2). However, the raw material crisis necessitates reduced TiO2 usage, leading to investigations into TiO2 modification techniques. The study introduces a novel approach by employing natural fibers, specifically loofah sponge, as a TiO2 support. This method aims to maintain photocatalytic activity while minimizing TiO2 content. The article explores using halloysite, a natural clay mineral, as a supportive material, enhancing mechanical strength and adsorption properties. The resulting TiO2/loofah-halloysite composites are evaluated for their efficacy in gas-phase photocatalytic oxidation of toluene and ethanol, chosen as representative VOCs. The conversion of toluene and ethanol on the composite was 88 % and 39 %, respectively, with high selectivity toward CO2. In addition to its high performance, the bio-composite was stable for several conversion cycles, keeping the conversion activity unchanged. The study contributes to developing green hybrid materials for VOC removal, showcasing potential applications across industries.

γ-Cyclodextrins as Supramolecular Reactors for the Three-component Aza-Darzens Reaction in Water.

In recent decades, many efforts have been devoted to studying reactions catalyzed in nanoconfined spaces. The most impressive aspect of catalysis in nanoconfined spaces is that the reactivity of the molecules can be smartly driven to disobey classical behavior. A green and efficient three-component aza-Darzens (TCAD) reaction using a catalytic amount of γ-cyclodextrins (CDs) in water has been developed to synthesize N-phenylaziridines. CDs effectively performed this reaction in an environmentally friendly setting, achieving good yields. The same reaction was then performed using polymeric γ-CD such as a γ-cyclodextrin polymer crosslinked (GCDPC) with epichlorohydrin, a sponge-like macroporous γ-cyclodextrin-based cryogel (GCDC), and a γ-cyclodextrin-based hydrogel (GCDH). The homogeneous and heterogeneous catalyst recovery was then studied, and it was proved to be easily recycled several times without relevant activity loss. Water, as a unique and eco-friendly reaction medium, has been utilized for the first time, to the best of our knowledge, in this reaction. The inclusion of the reagents in CDs has been studied and rationalized by NMR spectroscopy experiments and molecular modeling calculations. The credit of the presented protocol includes good yields and catalyst reusability and precludes the use of organic solvents.

Discovery of first novel sigma/HDACi dual-ligands with a potent in vitro antiproliferative activity.

Designing and discovering compounds for dual-target inhibitors is challenging to synthesize new, safer, and more efficient drugs than single-target drugs, especially to treat multifactorial diseases such as cancer. The simultaneous regulation of multiple targets might represent an alternative synthetic approach to optimize patient compliance and tolerance, minimizing the risk of target-based drug resistance due to the modulation of a few targets. To this end, we conceived for the first time the design and synthesis of dual-ligands σR/HDACi to evaluate possible employment as innovative candidates to address this complex disease. Among all synthesized compounds screened for several tumoral cell lines, compound 6 (Kiσ1R = 38 ± 3.7; Kiσ2R = 2917 ± 769 and HDACs IC50 = 0.59 µM) is the most promising candidate as an antiproliferative agent with an IC50 of 0.9 µM on the HCT116 cell line and no significant toxicity to normal cells. Studies of molecular docking, which confirmed the affinity over σ1R and a pan-HDACs inhibitory behavior, support a possible balanced affinity and activity between both targets.

Total Bio-Based Material for Drug Delivery and Iron Chelation to Fight Cancer through Antimicrobial Activity.

Bacterial involvement in cancer's development, along with their impact on therapeutic interventions, has been increasingly recognized. This has prompted the development of novel strategies to disrupt essential biological processes in microbial cells. Among these approaches, metal-chelating agents have gained attention for their ability to hinder microbial metal metabolism and impede critical reactions. Nanotechnology has also contributed to the antibacterial field by offering various nanomaterials, including antimicrobial nanoparticles with potential therapeutic and drug-delivery applications. Halloysite nanotubes (HNTs) are naturally occurring tubular clay nanomaterials composed of aluminosilicate kaolin sheets rolled multiple times. The aluminum and siloxane groups on the surface of HNTs enable hydrogen bonding with biomaterials, making them versatile in various domains, such as environmental sciences, wastewater treatment, nanoelectronics, catalytic studies, and cosmetics. This study aimed to create an antibacterial material by combining the unique properties of halloysite nanotubes with the iron-chelating capability of kojic acid. A nucleophilic substitution reaction involving the hydroxyl groups on the nanotubes' surface was employed to functionalize the material using kojic acid. The resulting material was characterized using infrared spectroscopy (IR), thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM), and its iron-chelating ability was assessed. Furthermore, the potential for drug loading-specifically, with resveratrol and curcumin-was evaluated through ultraviolet (UV) analysis. The antibacterial assay was evaluated following CLSI guidelines. The results suggested that the HNTs-kojic acid formulation had great antibacterial activity against all tested pathogens. The outcome of this work yielded a novel bio-based material with dual functionality as a drug carrier and an antimicrobial agent. This innovative approach holds promise for addressing challenges related to bacterial infections, antibiotic resistance, and the development of advanced therapeutic interventions.

New Insights into the Opioid Analgesic Profile of cis-(-)-N-Normetazocine-derived Ligands.

In this work, we report on the in vitro and in vivo pharmacological properties of LP1 analogs to complete the series of structural modifications aimed to generate compounds with improved analgesia. To do that, the phenyl ring in the N-substituent of our lead compound LP1 was replaced by an electron-rich or electron-deficient ring and linked through a propanamide or butyramide spacer at the basic nitrogen of the (-)-cis-N-normetazocine skeleton. In radioligand binding assays, compounds 3 and 7 were found to display nanomolar binding affinity for the µ opioid receptor (MOR) (Ki = 5.96 ± 0.08 nM and 1.49 ± 0.24 nM, respectively). In the mouse vas deferens (MVD) assay, compound 3 showed an antagonist effect against DAMGO ([D-Ala2, N-MePhe4, Gly-ol]-enkephalin), a highly selective MOR prototype agonist, whereas compound 7 produced naloxone reversible effect at MOR. Moreover, compound 7, as potent as LP1 and DAMGO at MOR, was able to reduce thermal and inflammatory pain assessed by the mouse tail-flick test and rat paw pressure thresholds (PPTs) measured by a Randall-Selitto test.

Computer-Assisted Design of Peptide-Based Radiotracers.

In medical imaging, techniques such as magnetic resonance imaging, contrast-enhanced computerized tomography, positron emission tomography (PET), and single-photon emission computed tomography (SPECT) are extensively available and routinely used for disease diagnosis. PET probes with peptide-based targeting are typically composed of small peptides especially developed to have high affinity and specificity for a range of cellular and tissue targets. These probes' key benefits include being less expensive than traditional antibody-based PET tracers and having an effective chemical modification process that allows them to be radiolabeled with almost any radionuclide, making them highly appealing for clinical usage. Currently, as with every pharmaceutical design, the use of in silico strategies is steadily growing in this field, even though it is not part of the standard toolkit used during radiopharmaceutical design. This review describes the recent applications of computational design approaches in the design of novel peptide-based radiopharmaceuticals.

Steered Molecular Dynamics Simulations Study on FABP4 Inhibitors.

Ordinary small molecule de novo drug design is time-consuming and expensive. Recently, computational tools were employed and proved their efficacy in accelerating the overall drug design process. Molecular dynamics (MD) simulations and a derivative of MD, steered molecular dynamics (SMD), turned out to be promising rational drug design tools. In this paper, we report the first application of SMD to evaluate the binding properties of small molecules toward FABP4, considering our recent interest in inhibiting fatty acid binding protein 4 (FABP4). FABP4 inhibitors (FABP4is) are small molecules of therapeutic interest, and ongoing clinical studies indicate that they are promising for treating cancer and other diseases such as metabolic syndrome and diabetes.

Heparan Sulfate and Enoxaparin Interact at the Interface of the Spike Protein of HCoV-229E but Not with HCoV-OC43.

It is known that the spike protein of human coronaviruses can bind to a secondary receptor, or coreceptor, to facilitate the virus entry. While HCoV-229E uses human aminopeptidase N (hAPN) as a receptor, HCoV-OC43 binds to 9-O-acetyl-sialic acid (9-O-Ac-Sia), which is linked in a terminal way to the oligosaccharides that decorate glycoproteins and gangliosides on the surface of the host cell. Thus, evaluating the possible inhibitory activity of heparan sulfate, a linear polysaccharide found in animal tissues, and enoxaparin sodium on these viral strains can be considered attractive. Therefore, our study also aims to evaluate these molecules' antiviral activity as possible adsorption inhibitors against non-SARS-CoV. Once the molecules' activity was verified in in vitro experiments, the binding was studied by molecular docking and molecular dynamic simulations confirming the interactions at the interface of the spike proteins.

Soluble peptidoglycan fragments produced by Limosilactobacillus fermentum with antiproliferative activity are suitable for potential therapeutic development: A preliminary report.

Currently, the use of probiotic strains and their products represents a promising innovative approach as an antagonist treatment against many human diseases. Previous studies showed that a strain of Limosilactobacillus fermentum (LAC92), previously defined as Lactobacillus fermentum, exhibited a suitable amensalistic property. The present study aimed to purify the active components from LAC92 to evaluate the biological properties of soluble peptidoglycan fragments (SPFs). The cell-free supernatant (CFS) and bacterial cells were separated after 48 h of growth in MRS medium broth and treated for isolation of SPFs. Antimicrobial activity and proliferation analysis on the human cell line HTC116 were performed using technologies such as xCELLigence, count and viability, and clonogenic analysis. MALDI-MS investigation and docking analysis were performed to determine the molecular structure and hypothetical mode of action, respectively. Our results showed that the antimicrobial activity was mainly due to SPFs. Moreover, the results obtained when investigating the SPF effect on the cell line HCT116 showed substantial preliminary evidence, suggesting their significant cytostatic and quite antiproliferative properties. Although MALDI was unable to identify the molecular structure, it was subsequently revealed by analysis of the bacterial genome. The amino acid structure is called peptide 92. Furthermore, we confirmed by molecular docking studies the interaction of peptide 92 with MDM2 protein, the negative regulator of p53. This study showed that SPFs from the LAC92 strain exerted anticancer effects on the human colon cancer HCT116 cell line via antiproliferation and inducing apoptosis. These findings indicated that this probiotic strain might be a potential candidate for applications in functional products in the future. Further examination is needed to understand the specific advantages of this probiotic strain and improve its functional features to confirm these data. Moreover, deeper research on peptide 92 could increase our knowledge and help us understand if it will be possible to apply to specific diseases such as CRC.

Portable Nanocomposite System for Wound Healing in Space.

It is well known that skin wound healing could be severely impaired in space. In particular, the skin is the tissue at risk of injury, especially during human-crewed space missions. Here, we propose a hybrid system based on the biocompatible poly 2-hydroxyethyl methacrylate (pHEMA) to actively support a nanocontainer filled with the drug. Specifically, during the cryo-polymerization of HEMA, halloysite nanotubes (HNTs) embedded with thymol (Thy) were added as a component. Thy is a natural pharmaceutical ingredient used to confer wound healing properties to the material, whereas HNTs were used to entrap the Thy into the lumen to ensure a sustained release of the drug. The as-obtained material was characterized by chemical-physical methods, and tests were performed to assess its ability for a prolonged drug release. The results showed that the adopted synthetic procedure allows the formation of a super absorbent system with good swelling ability that can contain up to 5.5 mg of Thy in about 90 mg of dried sponge. Releasing tests demonstrated the excellent material's ability to perform a slow controlled delivery of 62% of charged Thy within a week. As humans venture deeper into space, with more extended missions, limited medical capabilities, and a higher risk of skin wounds, the proposed device would be a versatile miniaturized device for skin repair in space.

Design, synthesis, in vitro evaluation, and molecular modeling studies of N-substituted benzomorphans, analogs of LP2, as novel MOR ligands.

6,7-Benzomorphans have been investigated in medicinal chemistry for developing new drugs. This nucleus could be considered a versatile scaffold. The physicochemical properties of benzomorphan N-substituent are crucial in achieving a definite pharmacological profile at opioid receptors. Thus, the dual-target MOR/DOR ligands LP1 and LP2 were obtained through N-substituent modifications. Specifically, LP2, bearing as N-substituent the (2R/S)-2-methoxy-2- phenylethyl group, is a dual-target MOR/DOR agonist and is successful in animal models of inflammatory and neuropathic pain. To obtain new opioid ligands, we focused on the design and synthesis of LP2 analogs. First, the 2-methoxyl group of LP2 was replaced by an ester or acid functional group. Then, spacers of different lengths were introduced at N-substituent. In-vitro, their affinity profile versus opioid receptors has been performed through competition binding assays. Molecular modeling studies were conducted to deeply analyze the binding mode and the interactions between the new ligands and all opioid receptors.

1,2-Dibenzoylhydrazine as a Multi-Inhibitor Compound: A Morphological and Docking Study.

In the framework of the multitarget inhibitor study, we report an in silico analysis of 1,2-dibenzoylhydrazine (DBH) with respect to three essential receptors such as the ecdysone receptor (EcR), urease, and HIV-integrase. Starting from a crystallographic structural study of accidentally harvested crystals of this compound, we performed docking studies to evaluate the inhibitory capacity of DBH toward three selected targets. A crystal morphology prediction was then performed. The results of our molecular modeling calculations indicate that DBH is an excellent candidate as a ligand to inhibit the activity of EcR receptors and urease. Docking studies also revealed the activity of DBH on the HIV integrase receptor, providing an excellent starting point for developing novel inhibitors using this molecule as a starting lead compound.

Ligand Growing Experiments Suggested 4-amino and 4-ureido pyridazin-3(2H)-one as Novel Scaffold for FABP4 Inhibition.

Fatty acid binding protein (FABP4) inhibitors are of synthetic and therapeutic interest and ongoing clinical studies indicate that they may be a promise for the treatment of cancer, as well as other diseases. As part of a broader research effort to develop more effective FABP4 inhibitors, we sought to identify new structures through a two-step computing assisted molecular design based on the established scaffold of a co-crystallized ligand. Novel and potent FABP4 inhibitors have been developed using this approach and herein we report the synthesis, biological evaluation and molecular docking of the 4-amino and 4-ureido pyridazinone-based series.

Targeting the SARS-CoV-2 HR1 with Small Molecules as Inhibitors of the Fusion Process.

The rapid and global propagation of the novel human coronavirus that causes severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has produced an immediate urgency to discover promising targets for the treatment of this virus. In this paper, we studied the spike protein S2 domain of SARS-CoV-2 as it is the most conserved component and controls the crucial fusion process of SARS-CoV-2 as a target for different databases of small organic compounds. Our in silico methodology, based on pharmacophore modeling, docking simulation and molecular dynamics simulations, was first validated with ADS-J1, a potent small-molecule HIV fusion inhibitor that has already proved effective in binding the HR1 domain and inhibiting the fusion core of SARS-CoV-1. It then focused on finding novel small molecules and new peptides as fusion inhibitors. Our methodology identified several small molecules and peptides as potential inhibitors of the fusion process. Among these, NF 023 hydrate (MolPort-006-822-583) is one of the best-scored compounds. Other compounds of interest are ZINC00097961973, Salvianolic acid, Thalassiolin A and marine_160925_88_2. Two interesting active peptides were also identified: AP00094 (Temporin A) and AVP1227 (GBVA5). The inhibition of the spike protein of SARS-CoV-2 is a valid target to inhibit the virus entry in human cells. The discussed compounds reported in this paper led to encouraging results for future in vitro tests against SARS-CoV-2.

Adipocyte fatty acid binding protein 4 (FABP4) inhibitors. An update from 2017 to early 2022.

The fatty acid binding protein 4 (FABP4) is a protein predominantly expressed in macrophages and adipose tissue, where it regulates fatty acids storage and lipolysis and is an essential mediator of inflammation. Small molecule inhibitors of FABP4 have attracted interest following the recent publications of beneficial pharmacological effects of these compounds for the treatment of metabolic syndrome and, more recently, for other pathologies. Since the synthesis of the BMS309403, one of the first selective and effective FABP4 inhibitors, hundreds of other inhibitors have been synthesized (i.e., derivatives of niacin, quinoxaline, aryl-quinoline, bicyclic pyridine, urea, aromatic compounds and other novel heterocyclic compounds). This review updates the recently reported (2017 to early 2022) molecules as adipocyte fatty acid binding protein 4 inhibitors.