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International audience; Despite several studies on the Ajuga L. genus, the chemical composition of $Ajuga\ pyramidalis$, an alpine endemic species, is still largely unknown. The purpose of this study was to therefore deeper describe it, particularly from the phytochemistry and bioactivity perspectives. In that respect, $A.\ pyramidalis$ was investigated and 95% of the extracted mass of the plant was characterized by chromatography and mass spectrometry. Apart from the already determined chemical compounds, namely, harpagide and 8-O-acetylharpagide, two iridoids, and neoajugapyrin A, a neo-clerodane diterpene, and three polyphenols (echinacoside, verbascoside and teupoloside) were identified for the first time in $A.\ pyramidalis$. Incidentally, the first RX structure of a harpagoside derivative is also described in this paper. The extracts and isolated compounds were then evaluated for various biochemical or biological activities; notably a targeted action on the renewal of the epidermis was highlighted with potential applications in the cosmetic field for anti-aging.

International audience; Hydrolysis of β-lactam drugs, a major class of antibiotics, by serine or metallo-β-lactamases (SBL or MBL) is one of the main mechanisms for antibiotic resistance. New Delhi Metallo-β-lactamase-1 (NDM-1), an acquired metallo-carbapenemase first reported in 2009, is currently considered one of the most clinically relevant targets for the development of β-lactam-β-lactamase inhibitor combinations active on NDM-producing clinical isolates. Identification of scaffolds that could be further rationally pharmacomodulated to design new and efficient NDM-1 inhibitors is thus urgently needed. Fragment-based drug discovery (FBDD) has become of great interest for the development of new drugs for the past few years and combination of several FBDD strategies, such as virtual and NMR screening, can reduce the drawbacks of each of them independently. Our methodology starting from a high throughput virtual screening on NDM-1 of a large library (more than 700,000 compounds) allowed, after slicing the hit molecules into fragments, to build a targeted library. These hit fragments were included in an in-house untargeted library fragments that was screened by Saturation Transfer Difference (STD) Nuclear Magnetic Resonance (NMR). 37 fragments were finally identified and used to establish a pharmacophore. 10 molecules based on these hit fragments were synthesized to validate our strategy. Indenone 89 that combined two identified fragments shows an inhibitory activity on NDM-1 with a K i value of 4 µM.

The natural β-carboline alkaloids display similarities with neurotransmitters that can be favorably exploited to design bioactive and bioavailable drugs for Alzheimer's disease (AD) therapy. Several AD targets are currently and intensively being investigated, divided in different hypotheses: mainly the cholinergic, the amyloid β (Aβ), and the Tau hypotheses. To date, only symptomatic treatments are available involving acetylcholinesterase and NMDA inhibitors. On the basis of plethoric single-target structure-activity relationship studies, the β-carboline scaffold was identified as a powerful tool for fostering activity and molecular interactions with a wide range of AD-related targets. This knowledge can undoubtedly be used to design multitarget-directed ligands, a highly relevant strategy preferred in the context of multifactorial pathology with intricate etiology such as AD. In this review, we first individually discuss the AD targets of the β-carbolines, and then we focus on the multitarget strategies dedicated to the deliberate design of new efficient scaffolds.

Helianthemum nummularium is a European shrub growing at high altitude where it copes with a high level of stress. It was found to be overexpressed in ungulates diets compared to more abundant surrounding plants. These elements combined with the fact that H. nummularium from the Alps has never been investigated prompted us to study the phytochemical composition of its aerial parts. The analysis of the polar extract allowed for the isolation of eight compounds: p-hydroxybenzoic acid, tiliroside, kaempferol, astragalin, quercetin, plantainoside B, quercetin-3-O-glucoside, and quercetin-3-O-glucuronide. We investigated the effect of the polar extract and isolated compounds on nuclear factor erythroid 2-related factor 2 transcription factor, which regulates the expression of a wide variety of cytoprotective genes. We found that the ethanolic extract activates the expression of nuclear factor erythroid 2-related factor 2 in a dose-dependent manner, whereas the pure compounds were much less active. The activation of the nuclear factor erythroid 2-related factor 2 pathway by the plant extract could pave the way for studies to promote healthy aging through protection of cells against oxidative stress. Moreover, the isolated compounds could be investigated alone or in combination in the perspective of making the link between the ungulateʼs preference for this plant and possible use of it for self-medication.

The active component extraction from plants is the first crucial step in natural product research. For non-targeted extraction with an objective to isolate and characterize as many compounds as possible, the most classical technique, and the simplest to implement, is the Soxhlet extraction; however, it does not allow retrieving all the compounds from the plant (when it does not additionally cause artifacts during long heating process). The second most used technique is the extraction by successive macerations using solvents of increasing polarity. While this method is frequently used, few studies are available to rationalize and optimize it. Furthermore, this extraction technique requires some enhancement mainly for efficiency, environmental and time constraint reasons. Here, we present an innovative method of successive macerations using a mixture of solvents with the aim of simultaneously improving the yield, the partition of the compounds between the different phases and reducing the volume of extraction solvents. Triphasic systems were prepared by mixing five solvents (n-heptane, ethyl acetate, acetonitrile, butan-1-ol, water) in various proportions. To validate this method, the most efficient triphasic system was subsequently used to perform three successive macerations with a polarity gradient on a model plant before being extended to several alpine plants. Our results showed an overall good yield compared to conventional maceration techniques, while improving phase partition and reducing extraction time and volume of solvents.

International audience; Recent evidence shows that combination of correctors and potentiators, such as the drug ivacaftor (VX-770), can significantly restore the functional expression of mutated Cystic Fibrosis Transmembrane conductance Regulator (CFTR), an anion channel which is mutated in cystic fibrosis (CF). The success of these combinatorial therapies highlights the necessity of identifying a broad panel of specific binding mode modulators, occupying several distinct binding sites at structural level. Here, we identified two small molecules, SBC040 and SBC219, which are two efficient cAMP-independent potentiators, acting at low concentration of forskolin with EC50 close to 1 μM and in a synergic way with the drug VX-770 on several CFTR mutants of classes II and III. Molecular dynamics simulations suggested potential SBC binding sites at the vicinity of ATP-binding sites, distinct from those currently proposed for VX-770, outlining SBC molecules as members of a new family of potentiators.

Tauopathies, such as Alzheimer's disease, have been the subject of several hypotheses regarding the way to treat them. Hyperphosphorylation of tau protein leading to its aggregation is widely recognized as a key step in the development of these diseases resulting in neuronal dysfunction. The AcPHF6 model of tau that includes the shorter critical fragment involved in the protein aggregation was used in vitro to identify new potential inhibitors. Following a previous study on aurone derivatives, we herein compare this polyphenol family to a very close one, the benzylidene-2,3-dihydro-1H-inden-1-one (also named indanone). The structure activity relationship studies bring to light the importance of the hydroxylation pattern in both series: the more hydroxylated, the more active. In addition, the three-dimensional shape of the molecules is involved in their interaction mode with their target, thus defining their role either as inhibitors of fiber elongation or as fiber-binding molecules. Indanone 13a was identified as a promising inhibitor: its activity was confirmed by circular dichroism and atomic force microscopy studies.

Highly substituted purines were synthesized in good to high yields through a one-pot straightforward metal-free scalable method, using the Traube synthesis adapted to Vilsmeier-type reagents. From 5-amino-4-chloropyrimidines, new 9-aryl-substituted chloropurines and intermediates for peptide nucleic acid synthesis were prepared. Variant procedures allowing a rapid synthesis of ribonucleosides and 7-benzylpurine from 5-amidino-6-aminopyrimidines are also reported to illustrate the high potential of this versatile toolbox. This route appears to be particularly interesting in the field of nucleic acids for a direct and rapid access to various new 8-alkylpurine nucleosides.

Recent years have witnessed a considerable renewed interest for the uncommon flavonoid class of aurones. The characterization of two major biosynthetic machineries involved in their biosynthesis in flowers has encouraged the revival of phytochemical studies and identification of original structures, a process started almost seventy-five years ago. This review draws up an exhaustive map of natural occurrences of aurones their biosynthetic pathways and roles, with the aim to link their original structural properties among flavonoids to their place in evolution and the selective advantages they bring to some of the most advanced taxa in the plant kingdom.

International audience; Praziquantel (PZQ) is the first line drug for the treatment of human Schistosoma spp. worm infections. However, it suffers from low activity towards immature stages of the worm, and its prolonged use induces resistance/tolerance. During the last 40 years, 263 PZQ analogues have been synthesized and tested against Schistosoma spp. worms, but less than 10% of them showed significant activity. Here, we propose a rationalization of the chemical space of the PZQ derivatives by a ligand-based approach. First, we constructed an in-house database with all PZQ derivatives available in the literature. This analysis shows a high heterogeneity in the data. Fortunately, all studies include PZQ as a reference, permitting the classification of compounds into three classes according to their activities. Models involving ligand-based pharmacophore and logistic regression were performed. Five physicochemical parameters were identified as the best to explain the biological activity. In the end, we proposed new PZQ derivatives with modifications at positions 1 and 7, we analysed them with our models, and we observed that they can be more active than the previously synthesized derivatives. The main goal of this work was to conduct the most valuable meta-pharmacometrics/pharmacoinformatics analysis with all Praziquantel medicinal chemistry data available in the literature.

Ethnopharmacoalogical relevance The genus Nauclea in Africa comprises seven species. Among them, N. latifolia , N. diderrichii and N. pobeguinii are widely used by the local population in traditional remedies. Preparation from various parts of plants (e.g. roots, bark, leaves) are indicated by traditional healers for a wide range of diseases including malaria, pain, digestive ailments or metabolic diseases. Materials and methods A literature search was conducted on African species of the genus Nauclea using scientific databases such as Google Scholar, Pubmed or SciFinder. Every document of ethnopharmacological, phytochemical or pharmacological relevance and written in English or French were analyzed. Results and discussion The Nauclea genus is used as ethnomedicine all along sub-Saharan Africa. Several local populations consider Nauclea species as a major source of remedies for malaria. In this regard, two improved traditional medicines are currently under development using extracts from N. latifolia and N. pobeguinii . Concerning the chemical composition of the Nauclea genus, indoloquinolizidines alkaloids could be considered as the major class of compounds as they are reported in every analyzed Nauclea species, with numerous structures identified. Based on traditional indications a considerable amount of pharmacological studies were conducted to ensure activity and attempt to link them to the presence of particular compounds in plant extracts. Conclusion Many experimental studies using plant extracts of the African species of the genus Nauclea validate traditional indications (e.g. malaria and pain). However, bioactive compounds are rarely identified and therefore, there is a clear need for further evaluations as well as for toxicity experiments. The sustainability of these plants, especially of N. diderrichii , a threatened species, should be kept in mind to adapt local uses and preparation modes of traditional remedies.

Based on a screening process, we targeted substituted thiosemicarbazone as potential antileishmanial agents. Our objective was to identify the key structural elements contributing to the anti-parasite activity that might be used for development of effective drugs. A series of 32 compounds was synthesized and their efficacy was evaluated against the clinically relevant intracellular amastigotes of Leishmania donovani. From these, 22 compounds showed EC50 values below 10 mu M with the most active derivative (compound 14) showing an EC50 of 0.8 mu M with very low toxicity on two different mammalian cell lines. The most relevant structural elements required for higher activity indicate that the presence of a fused bicyclic aromatic ring such as a naphthalene bearing an alkyl or an alkoxy group substituent are prerequisites. Owing to the easy synthesis, high activity and low toxicity, the most active compounds could be considered as a lead for further development. (C) 2016 Elsevier Masson SAS. All rights reserved., The authors wish to acknowledge the support from the ICMG Nanobio Platform, Grenoble on which the NMR and MS were performed. This work was supported by the Spanish Grants Proyecto de Excelencia, Junta de Andalucia, Ref. CTS-7282 (to F.G.), SAF2012-34267 (to F.G.), FEDER funds from EU to F.G. The authors are grateful to ANR (Agence Nationale pour la Recherche) for financial support (Labex Arcane (ANR-11-LABX-0003-01)).

Covering up to 2016, Nauclea latifolia (syn. Sarcocephalus latifolius, Rubiaceae), commonly called the African pincushion tree, is a plant widely used in folk medicine in different regions of Africa for treating a variety of illnesses, including malaria, epilepsy and pain. N. latifolia has not only drawn the interest of traditional healers but also of phytochemists, who have identified a range of bioactive indole alkaloids in its tissue. More recently, following up on the traditional use of extracts in pain management, a bio-guided purification from the roots of the tree led to the identification of the active ingredient as tramadol, available as a synthetic analgesic since the 1970s. The discovery of this compound as a natural phytochemical was highlighted worldwide. This review focuses on the correlation between extracted compounds and pharmacological activities, paying special attention to infectious diseases and neurologically-related disorders. A critical analysis of the data reported so far on the natural origin of tramadol and its proposed biosynthesis is also presented.

We designed bidentate ligands to target PDZ domains through two binding sites: site S0, delimited by the GLGF loop, and site S1, a zone situated around loop β B /β C . A molecular docking study allowed us to design a generic S0 binder, to which was attached a variable size linker, itself linked to an amino acid aimed to interact with the S1 site of PDZ domains. A series of 15 novel bidentate ligands was prepared in 6–11 steps in good overall yield (24–43%). Some of these ligands showed an inhibitory activity against serotonin 5-HT2A receptor/PSD-95 interaction. This was assessed by pull-down assay using a synthetic decapeptide corresponding to the C-terminal residues of the receptor as a bait.

IF : 2,88; International audience; In the study of previously reported modulators of CFTR chloride channels that are cyclic methylglyoxal (MG) diadducts (CMGD) to aromatic α-aminoazaheterocycles, we optimized a new expeditious one pot route for preparing in water novel aromatic polycyclic azaheterocycles and described 5-pyrimidinols antioxidants through the formation of 2-oxoaldehyde diadducts to aromatic α-aminoazaheterocycles, amidines, guanidines and thiourea. In regard to the importance as biomarkers of diabetic complications of the 5-pyrimidinols "argpyrimidines" formed in proteins from MG and arginine residues, we demonstrated that argpyrimidines are slowly formed under physiological conditions from CMGD to arginine derivatives according to the synthesis route described. Among the 5-pyrimidinol derivatives prepared, two polycyclic derivatives appeared to inhibit strongly the activity of CFTR channels in wt-CHO cells.

International audience; Disrupting the interaction between the PDZ protein PSD-95 and the C-terminal domain of the 5-HT2A serotonin receptor has been shown to reduce hyperalgesia in a rodent model of neuropathic pain. Here, we designed and synthesized PDZ ligands capable of binding to the first PDZ domain (PDZ1) of the PSD-95 protein and evaluated their biological activity in vitro and in vivo. A series of substituted indoles was identified by docking simulations, and six novel analogues were synthesized. Three analogues displayed strong interactions with the first PDZ domain (PDZ1) of PDZ-95 in 1H-15N heteronuclear single-quantum coherence (HSQC) experiments and two of them were able to inhibit the interaction between PSD-95 and the 5-HT2A receptor in vitro. We identified compound 8b as the analogue able to significantly suppress mechanical hyperalgesia in an experimental model of traumatic neuropathic pain in the rat. This effect was suppressed by the coadministration of the 5-HT2A receptor antagonist M100907, consistent with an inhibitory effect upon 5-HT2A receptor/PSD-95 interaction. Finally, we determined an NMR-restraint driven model structure for the PSD95 PDZ1/8b complex, which confirms that indole 8b binds to the putative PDZ-ligand binding site.

International audience; Disrupting the interaction between the PDZ protein, PSD-95, and its target ligands (such as the glutamate NMDA receptor or the serotonin 5-HT2A receptor) was found to reduce hyperalgesia in various models of neuropathic pain. Here, we set out to identify lead molecules which would interact with PSD-95, and hence, would potentially display analgesic activity. We describe the virtual screening of the Asinex and Cambridge databases which together contain almost one million molecules. Using three successive docking filters and visual inspection, we identified three structural classes of molecules and synthesized a potential lead compound from each class. The binding of the molecules with the PDZ domains of PSD-95 was assessed by 1H-15N HSQC NMR experiments. The analgesic activity of the best ligand, quinoline 2, was evaluated in vivo in a model of neuropathic pain and showed promising results.

We synthesized small organic molecules designed as PDZ ligands. These indole-based compounds were evaluated for their interaction with the PDZ1 domain of the post-synaptic density 95 (PSD-95) protein. Three molecules were found to interact with the targeted PDZ protein by NMR. One of them showed chemical shift perturbations closely related to the natural ligands.

International audience; One of the major therapeutic strategy in cystic fibrosis aims at developing modulators of cystic fibrosis transmembrane conductance regulator (CFTR) channels. We recently discovered methylglyoxal alpha-aminoazaheterocycle adducts, as a new family of CFTR inhibitors. In a structure-activity relationship study, we have now identified GPact-11a, a compound able not to inhibit but to activate CFTR. Here, we present the effect of GPact-11a on CFTR activity using in vitro (iodide efflux, fluorescence imaging and patch-clamp recordings), ex vivo (short-circuit current measurements) and in vivo (salivary secretion) experiments. We report that GPact-11a: 1) is an activator of CFTR in several airway epithelial cell lines; 2) activates rescued F508del-CFTR in nasal, tracheal, bronchial, pancreatic cell lines and in human CF ciliated epithelial cells, freshly dissociated from lung samples; 3) stimulates ex vivo the colonic chloride secretion and increases in vivo the salivary secretion in cftr(+/+) but not cftr(-/-) mice; and 4) is selective for CFTR because its effect is inhibited by CFTR(inh)-172, GlyH-101, glibenclamide and GPinh-5a. To conclude, this work identifies a selective activator of wild-type and rescued F508del-CFTR. This nontoxic and water-soluble agent represents a good candidate, alone or in combination with a F508del-CFTR corrector, for the development of a CFTR modulator in cystic fibrosis.

The cystic fibrosis transmembrane conductance regulator (CFTR) represents the main Cl(-) channel in the apical membrane of epithelial cells for cAMP-dependent Cl(-) secretion. Here we report on the synthesis and screening of a small library of nontoxic alpha-aminoazaheterocycle-methylglyoxal adducts, inhibitors of wild-type (WT) CFTR and G551D-, G1349D-, and F508del-CFTR Cl(-) channels. In whole-cell patch-clamp experiments of Chinese hamster ovary (CHO) cells expressing WT-CFTR, we recorded rapid and reversible inhibition of forskolin-activated CFTR currents in the presence of the adducts 5a and 8a,b at 10 pM concentrations. Using iodide efflux experiments, we compared concentration-dependent inhibition of CFTR with glibenclamide (IC(50) = 14.7 microM), 3-[(3-trifluoromethyl)phenyl]-5-[(4-carboxyphenyl-)methylene]-2-thioxo-4-thiazolidinone (CFTR(inh)-172) (IC(50) = 1.2 microM), and alpha-aminoazaheterocycle-methylglyoxal adducts and identified compounds 5a (IC(50) = 71 pM), 8a,b (IC(50) = 2.5 nM), and 7a,b (IC(50) = 3.4 nM) as the most potent inhibitors of WT-CFTR channels. Similar ranges of inhibition were also found when these compounds were evaluated on CFTR channels with the cystic fibrosis mutations F508del (in temperature-corrected human airway epithelial F508del/F508del CF15 cells)-, G551D-, and G1349D-CFTR (expressed in CHO and COS-7 cells). No effect of compound 5a was detected on the volume-regulated or calcium-regulated iodide efflux. Picomolar inhibition of WT-CFTR with adduct 5a was also found using a 6-methoxy-N-(3-sulfopropyl)-quinolinium fluorescent probe applied to the human tracheobronchial epithelial cell line 16HBE14o-. Finally, we found comparable inhibition by 5a or by CFTR(inh)-172 of forskolin-dependent short-circuit currents in mouse colon. To the best of our knowledge, these new nontoxic alpha-aminoazaheterocycle-methylglyoxal adducts represent the most potent compounds reported to inhibit CFTR chloride channels.