In recent years, Biophytum umbraculum Welw. (Oxalidaceae) has undergone several phytochemical and pharmacological investigations. Although its major phytochemical classes have been characterized, few isolated compounds have been reported. The previously detected phytoconstituents, along with the documented antioxidant and anti-inflammatory activities, both align with a potential antiproliferative effect. This study aims to complement the existing chemotaxonomic profile of B. umbraculum through the isolation and identification of phytoconstituents and to evaluate the antiproliferative potential of its extracts. Hexane, ethyl acetate, and methanolic extracts of B. umbraculum were screened against two human adherent cell lines, breast (MCF-7) and cervical (SiSo) adenocarcinomas, by using the crystal violet staining assay. The hexane extract inhibited both MCF-7 and SiSo cell proliferation with IC50 values of 8.93 +/- 0.07 and 14.59 +/- 0.08 & micro;g/mL, respectively. The ethyl acetate extract showed activity against both cell lines, with IC50 values of 12.60 +/- 0.14 and 13.10 +/- 0.04 & micro;g/mL, respectively. However, the methanolic extract was inactive on the MCF-7 cell line and only slightly active on the SiSo cell line. Chromatographic fractionations led to the isolation of ursolic acid from the active ethyl acetate extract and rutin from the methanolic extract. A further antiproliferative evaluation is warranted to confirm the contribution of ursolic acid to the effect of the ethyl acetate extract. Additional fractionations may uncover more phytoconstituents of diverse pharmaceutical interests.

Heterotetrameric KV7.2/3 potassium channels were retrospectively identified as the target of the analgesic flupirtine and the antiepileptic retigabine (ezogabine). Clinical utility of these agents ended after decades or 6 years, respectively, before their full scope was explored. Market withdrawals in 2017 and 2018 hampered research in other medical fields and left a gap for researchers using these compounds off-label in experimental indications and for patients with KV7.2/3 malfunctions. Failure of these drugs might be regarded as a reason to abandon this class of compounds, due to the notion that toxicity might be a class effect and to competitive markets. Yet, evidence accumulated that the toxicity of both compounds is not an inherent property of modulators of KV7.2/3 channels, but rather the result of an oxidation-sensitive metabophore/toxicophore. Second, epilepsy associated with KV7.2/3 channelopathies might rationally be addressed best with modulators of this validated drug target. Employing retrometabolic drug design to remodel the enzyme-labile carbamate structure and the central highly substituted ring, azetukalner (formerly encukalner, XEN1101) emerged from the unlucky forerunners. This structural analog of retigabine exhibits improved metabolic stability, increased potency, and enhanced blood-brain barrier penetration compared with its predecessor. This review details the synthesis, physicochemical properties, and clinical results of azetukalner.

The first-in-class KV7.2/3 channel activator flupirtine, was considered a potent analgesic in various pain conditions. However, it was withdrawn from the market in 2018 due to severe hepatotoxicity associated with forming reactive metabolites. In this work, we present new KV7.2/3 channel modulators that have been evaluated in several preclinical mouse pain models, including acute thermally and chemically induced pain, diabetes-induced neuropathic pain, and chemotherapy-induced peripheral neuropathy. In addition, the new KV7.2/3 channel activators were compared with the reference substances flupirtine, retigabine, and azetukalner, focusing on the inhibition of the hERG channel, nephrotoxicity, metabolic stability, and the formation of reactive metabolites. A flupirtine analog with a pyrimidine scaffold (8) showed clear advantages over the reference compounds tested, with a favorable toxicity profile, a 2 h in vitro half-life when incubated with human liver microsomes, and a 9-fold reduction in the formation of reactive metabolites compared to flupirtine. This compound also demonstrated strong in vivo efficacy in pain models, making it a promising candidate for further development of KV7.2/3 channel activators.

The previously unknown mol­ecular SCXRD structure and crystal-packing pattern of a diclofenac derivative were assessed in detail including intra- and inter­molecular inter­actions such as hydrogen bonds and halogen bonds. The validity of these inter­actions was further evaluated computationally using QM calculations.

The title compound, C15H15Cl3NO2, was synthesized from diclofenac and chloromethyl chlorosulfate under phase-transfer conditions, and crystallizes in the monoclinic space group P21/c. As a result of steric strain, the two adjacent aromatic six-membered rings cannot be co-planar, while the terminal ring on one side of the molecule and the methyl acetate moiety atoms on the other reside roughly in the same plane. The angle between the planes of the two aromatic rings is rather wide at 64.27 (8)°. The crystal is tightly packed and consolidated by a large number and notable range of intermolecular contacts, including relatively strong classical hydrogen bonds but also halogen bonds and even short contacts between chlorine atoms and π-bonds. The intermolecular interactions were further analysed using DFT methods, the results of which are discussed in comparison to the experimental X-ray data.

The synthesis of asymmetric acylals starting from chloromethyl esters has been comprehensively documented in the extant literature. However, this process is typically associated with the use of toxic and environmentally hazardous solvents, such as N,N-dimethylformamide (DMF) or, less frequently, N-methylpyrrolidone (NMP), as well as an often protracted (up to several days) reaction time. In this study, we demonstrate that dihydrolevoglucosenone (Cyrene), a green solvent, in combination with microwave irradiation, leads to a substantial reduction in reaction time by several orders of magnitude (a few minutes instead of hours or days) with good to excellent yields. In certain instances, precipitation is a sufficient method for the removal of high boiling Cyrene, resulting in an approximate 70 fold improvement of molar efficiency (Mol E.%) compared to standard procedures. In case of more lavish purification, Dry Column Vacuum Chromatography (DCVC) has been demonstrated to be a suitable purification approach, characterised by its expeditious nature and its significantly reduced generation of organic waste in comparison with conventional column chromatography. Building on this and in addition to the green synthesis, an ultra-low cost and highly efficient chromatographic method, based on similar principles to the DCVC, has been developed, resulting in a 12 fold improvement in the E-factor versus column chromatography. The protocol is robust for acylal synthesis for a wide range of carboxylic acids up to relevant drugs and biochemically important reagents. It provides the opportunity to create large libraries of acylal compounds for medicinal chemistry or biochemistry approaches in a short time.

Results of scientific work in chemistry can usually be obtained in the form of materials and data. A big step towards transparency and reproducibility of the scientific work can be gained if scientists publish their data in research data repositories in a FAIR manner. Nevertheless, in order to make chemistry a sustainable discipline, obtaining FAIR data is insufficient and a comprehensive concept that includes preservation of materials is needed. In order to offer a comprehensive infrastructure to find and access data and materials that were generated in chemistry projects, we combined the infrastructure Chemotion repository with an archive for chemical compounds. Samples play a key role in this concept: we describe how FAIR metadata of a virtual sample representation can be used to refer to a physically available sample in a materials’ archive and to link it with the FAIR research data gained using the said sample. We further describe the measures to make the physically available samples not only FAIR through their metadata but also findable, accessible and reusable.

The title compound, C15H15Cl3NO2, was synthesized from diclofenac and chloro-methyl chloro-sulfate under phase-transfer conditions, and crystallizes in the monoclinic space group P21/c. As a result of steric strain, the two adjacent aromatic six-membered rings cannot be co-planar, while the terminal ring on one side of the mol-ecule and the methyl acetate moiety atoms on the other reside roughly in the same plane. The angle between the planes of the two aromatic rings is rather wide at 64.27 (8)°. The crystal is tightly packed and consolidated by a large number and notable range of inter-molecular contacts, including relatively strong classical hydrogen bonds but also halogen bonds and even short contacts between chlorine atoms and π-bonds. The inter-molecular inter-actions were further analysed using DFT methods, the results of which are discussed in comparison to the experimental X-ray data.

The voltage-gated potassium channel KV7.2/3 is gaining attention for its association with several medical indications. While recently reported, potent compounds aimed to fill the therapeutic gap left by market-withdrawn activators, key physicochemical parameters did not meet the requirements of potential drug candidates. Targeting the membrane-located channel requires subtly balancing lipophilicity, activity, and aqueous solubility. This publication describes the lead optimization of a highly active compound toward optimized physicochemical parameters. Out of 42 newly synthesized compounds, 30 showed activity on KV7.2/3 channels, and 15 had also an increased solubility compared the to hit compound. The integration of a three-dimensional bulky structure and the probable onset of chameleonic behavior, led to a 20-fold solubility increase (S = 21.7 vs 1.1 μM) and only slightly reduced potency (pEC50 = 7.42 vs 7.96) for the lead. Additionally, the target engagement of the compound was theoretically enhanced by a reduction of membrane retention.

Chiral analysis is an essential part of the development and quality control of enantiopure pharmaceuticals. Supercritical fluid chromatography (SFC) emerged as a powerful tool for the chiral separation of drugs, however, its implementation in the pharmacopoeia remains limited. In this study, we developed a rapid SFC-UV method for the impurity control of S-dapoxetine, enabling simultaneous chiral and achiral analysis in less than 20min. The method was validated according to ICH Q2(R2) guidelines and demonstrated sufficient sensitivity, precision and accuracy down to 2.5µgmL-1. A binary acid-base additive mixture was used to modify chemo- and stereoselectivity, achieving baseline separation of all relevant analytes. During method development, an unusual retention behaviour of basic analytes was observed, leading to a thermodynamic investigations using the Van 't Hoff analysis. This revealed a rare case of entropy-driven retention, with strong acidic additives like trifluoroacetic acid leveraging the effect for basic analytes. Further investigations involving 15 diverse chiral amines, as well as molecular dynamic simulations, showed that isopropanol stabilizes the helical amylose backbone by reducing excessive flexibility, thereby increasing the enantioselective separation efficiency. Additionally, strong acids were found to form transient ion-pairs with basic analytes, which are favoured in the supercritical environment. The neutral complexes impact retention depending on the amine substitution pattern and may suppress polar and enhance hydrophobic interactions. These results underscore the potential application of combined additive systems to enhance SFC applications in the field of ionizable analytes.

Fexinidazole, a drug active against trypanosomiasis and leishmaniasis, is a rare example of a nitroaromatic compound approved under the contemporary drug discovery framework. In an earlier study, we showed that the nitro group is absolutely required for antileishmanial activity. The current study employed X-ray crystallography to unveil the structural intricacies of fexinidazole and its principal metabolites, as well as electroanalytical analyses to characterize the reduction properties of the aromatic nitro group. Fexinidazole showcases a predominantly planar geometry with two distinct conformers. While most metrical parameters were conserved between fexinidazole and its metabolites, differences in the methyl ether bridge and S-methyl tail indicated distinctive preferences in molecular arrangement: conformer I of fexinidazole closely resembles the sulfone metabolite, while conformer II aligns with the sulfoxide metabolite. On the other hand, electroanalytical analysis of fexinidazole revealed a pH-dependent, two-step nitro group reduction mechanism, involving an initial concerted transfer of an electron and a proton, followed by the uptake of three electrons and three protons to likely form a hydroxylamine species. These findings characterize the molecular architecture and reduction mechanism of fexinidazole, providing valuable insights into its structural features and activation mechanism required for anti-infective activity.

KDM4 histone demethylases became an exciting target for inhibitor development as the evidence linking them directly to tumorigenesis mounts. In this study, we set out to better understand the binding cavity using an X-ray crystallographic approach to provide a detailed landscape of possible interactions within the under-investigated region of KDM4. Our design strategy was based on utilizing known KDM binding motifs, such as nicotinic acid and tetrazolylhydrazides, as core motifs that we decided to enrich with flexible tails to map the distal histone binding site. The resulting X-ray structures of the novel compounds bound to KDM4D, a representative of the KDM4 family, revealed the interaction pattern with distal residues in the histone-binding site. The most prominent protein rearrangement detected upon ligand binding is the loop movement that blocks the accessibility to the histone binding site. Apart from providing new sites that potential inhibitors can target, the novel compounds may prove helpful in exploring the capacity of ligands to bind in sites distal to the cofactor-binding site of other KDMs or 2-oxoglutarate (2OG)-dependent oxygenases. The case study proves that combining a strong small binding motif with flexible tails to probe the binding pocket will facilitate lead discovery in classical drug-discovery campaigns, given the ease of accessing X-ray quality crystals.

The TGF beta type II receptor (T beta RII) is a central player in all TGF beta signaling downstream events, has been linked to cancer progression, and thus, has emerged as an auspicious anti-TGF beta strategy. Especially its targeted degradation presents an excellent goal for effective TGF beta pathway inhibition. Here, cellular structure-activity relationship (SAR) data from the T beta RII degrader chemotype 1 was successfully transformed into predictive ligand-based pharmacophore models that allowed scaffold hopping. Two distinct 3,4-disubstituted indoles were identified from virtual screening: tetrahydro-4-oxo-indole 2 and indole-3-acetate 3. Design, synthesis, and screening of focused amide libraries confirmed 2r and 3n as potent TGF beta inhibitors. They were validated to fully recapitulate the ability of 1 to selectively degrade T beta RII, without affecting T beta RI. Consequently, 2r and 3n efficiently blocked endothelial-to-mesenchymal transition and cell migration in different cancer cell lines while not perturbing the microtubule network. Hence, 2 and 3 present novel T beta RII degrader chemotypes that will (1) aid target deconvolution efforts and (2) accelerate proof-of-concept studies for small-molecule-driven T beta RII degradation in vivo.

3,4-bridged indoles are underrepresented among the vast number of indoles described in the literature. Attempts to access 3,4-macrocyclized indoles led to the unexpected formation of a novel tetracyclic indole through intramolecular acid-catalyzed ring contraction. The herein-established one-step synthetic route provides an excellent medicinal chemistry platform for the construction of screening libraries covering a unique chemical space of indoles.

Glutamate dehydrogenases (GDHs) are key enzymes at the crossroads of N and C metabolism in plants. Legumes, whose N metabolism is particularly intricate, possess a unique type of GDH. This study presents an analysis of a legume-type GDH (isoform 2) from Medicago truncatula (MtGDH2). We measured MtGDH2 activity in both the Glu → 2-oxoglutarate (2OG) and 2OG → Glu reaction directions and obtained kinetic parameters for Glu, 2OG, NAD+, and NADH. Inhibition assays revealed that compounds possessing di- or tricarboxylates act as inhibitors of plant GDHs. Interestingly, 2,6-pyridinedicarboxylate (PYR) weakly inhibits MtGDH2 compared to Arabidopsis thaliana homologs. Furthermore, we explored tetrazole derivatives to discover 3-(1H-tetrazol-5-yl)benzoic acid (TBA) as an MtGDH2 inhibitor. The kinetic experiments are supported by six crystal structures, solved as: (i) unliganded enzyme, (ii) trapping the reaction intermediate 2-amino-2-hydroxyglutarate and NAD+, and also complexed with NAD+ and inhibitors such as (iii) citrate, (iv) PYR, (v) isophthalate, and (vi) TBA. The complex with TBA revealed a new mode of action that, in contrast to other inhibitors, prevents domain closure. This discovery points to TBA as a starting point for the development of novel GDH inhibitors to study the functions of GDH in plants and potentially boost biomass production.

The DNA repair protein PARP-1 emerged as a valuable target in the treatment of tumor entities with deficiencies of BRCA1/2, such as breast cancer. More recently, the application of PARP inhibitors (PARPi) such as olaparib has been expanded to other cancer entities including colorectal cancer (CRC). We previously demonstrated that PARP-1 is overexpressed in human CRC and promotes CRC progression in a mouse model. However, acquired resistance to PARPi and cytotoxicity-mediated adverse effects limit their clinical applicability. Here, we detailed the role of PARP-1 as a therapeutic target in CRC and studied the efficacy of novel PARPi compounds in wildtype (WT) and DNA repair-deficient CRC cell lines together with the chemotherapeutics irinotecan (IT), 5-fluorouracil (5-FU), and oxaliplatin (OXA). Based on the ComPlat molecule archive, we identified novel PARPi candidates by molecular docking experiments in silico, which were then confirmed by in vitro PARP activity measurements. Two promising candidates (X17613 and X17618) also showed potent PARP-1 inhibition in a CRC cell-based assay. In contrast to olaparib, the PARPi candidates caused no PARP-1 trapping and, consistently, were not or only weakly cytotoxic in WT CRC cells and their BRCA2- or ATR-deficient counterparts. Importantly, both PARPi candidates did not affect the viability of nonmalignant human colonic epithelial cells. While both olaparib and veliparib increased the sensitivity of WT CRC cells towards IT, no synergism was observed for X17613 and X17618. Finally, we provided evidence that all PARPi (olaparib > veliparib > X17613 > X17618) synergize with chemotherapeutic drugs (IT > OXA) in a BRCA2-dependent manner in CRC cells, whereas ATR deficiency had only a minor impact. Collectively, our study identified novel lead structures with potent PARP-1 inhibitory activity in CRC cells but low cytotoxicity due to the lack of PARP-1 trapping, which synergized with IT in homologous recombination deficiency.

Diesters of geminal diols (R-CH(O-CO-R′)2, RR′C(OCOR″)2, etc. with R = H, aryl or alkyl) are termed acylals according to IUPAC recommendations (Rule P-65.6.3.6 Acylals) if the acids involved are carboxylic acids. Similar condensation products can be obtained from various other acidic structures as well, but these related “non-classical acylals”, as one might call them, differ in various aspects from classical acylals and will not be discussed in this article. Carboxylic acid diesters of geminal diols play a prominent role in organic chemistry, not only in their application as protective groups for aldehydes and ketones but also as precursors in the total synthesis of natural compounds and in a variety of organic reactions. What is more, acylals are useful as a key structural motif in clinically validated prodrug approaches. In this review, we summarise the syntheses and chemical properties of such classical acylals and show what potentially under-explored possibilities exist in the field of drug design, especially prodrugs, and classify this functional group in medicinal chemistry.

The lack of adequate anti-leishmanial therapies has led to the continued suffering of millions of people from developing nations. Moreover, optimism for a therapeutic intervention by fexinidazole was dashed due to the inability to maintain cures and control unwanted side effects. To solve these shortcomings, the structural elements of fexinidazole responsible for anti-leishmanial activity and toxicities were explored. Accordingly, a systematic analog design approach was taken for the synthesis of 24 novel analogs. We established the structural features important for activity and identified modifications that improved the hERG receptor safety and liver microsomal metabolic stability. Compared to fexinidazole, the S-configured imidazolooxazole analog 51 exhibited 25-fold greater potency against miltefosine resistant L. donovani amastigotes, greater metabolic stability and little hERG receptor inhibition. Replacement of the toxicophore nitro group for a cyano group resulted in a complete loss of anti-leishmanial activity. The SAR findings should be useful in the further development of this important class of anti-leishmanial agents.

The pharmaceutical industry relies heavily on analytical techniques for identifying and characterizing drug compounds. In this experiment, undergraduate pharmacy students explored the applications of near-infrared spectroscopy for pharmaceutical analysis and its potential for identifying patterns and relationships among pharmaceutical samples. In addition, they were introduced to the chemometrics field using classical pretreatment and data exploration methods. To reduce the need for expensive instrumental equipment, we have developed a small and affordable device based on the DLP NIRscan Nano EVM by Texas Instruments using free software solutions and a 3D-printed case for Raspberry Pi single-board computers. The goal of the experiment was to guide students through all the necessary steps for measuring and analyzing samples using NIR spectroscopy and to encourage their learning through the application of mathematical methods in a defined laboratory setting.

Cold physical plasma is a partially ionized gas operated at body temperature and utilized for heat-sensitive technical and medical purposes. Physical plasma is a multi-component system consisting of, e.g., reactive species, ions and electrons, electric fields, and UV light. Therefore, cold plasma technology is an interesting tool for introducing biomolecule oxidative modifications. This concept can be extended to anticancer drugs, including prodrugs, which could be activated in situ to enhance local anticancer effects. To this end, we performed a proof-of-concept study on the oxidative prodrug activation of a tailor-made boronic pinacol ester fenretinide treated with the atmospheric pressure argon plasma jet kINPen operated with either argon, argon-hydrogen, or argon-oxygen feed gas. Fenretinide release from the prodrug was triggered via Baeyer-Villiger-type oxidation of the boron-carbon bond based on hydrogen peroxide and peroxynitrite, which were generated by plasma processes and chemical addition using mass spectrometry. Fenretinide activation led to additive cytotoxic effects in three epithelial cell lines in vitro compared to the effects of cold plasma treatment alone regarding metabolic activity reduction and an increase in terminal cell death, suggesting that cold physical plasma-mediated prodrug activation is a new direction for combination cancer treatment studies.