Showing papers in "Chemical Biology & Drug Design in 2015"
TL;DR: A range of therapeutic strategies that could be employed in conjunction with antibiotics and may help to prolong the life span of these life‐saving drugs are explored.
Abstract: The growing number of bacterial pathogens that are resistant to numerous antibiotics is a cause for concern around the globe. There have been no new broad-spectrum antibiotics developed in the last 40 years, and the drugs we have currently are quickly becoming ineffective. In this article, we explore a range of therapeutic strategies that could be employed in conjunction with antibiotics and may help to prolong the life span of these life-saving drugs. Discussed topics include antiresistance drugs, which are administered to potentiate the effects of current antimicrobials in bacteria where they are no longer (or never were) effective; antivirulence drugs, which are directed against bacterial virulence factors; host-directed therapies, which modulate the host's immune system to facilitate infection clearance; and alternative treatments, which include such therapies as oral rehydration for diarrhea, phage therapy, and probiotics. All of these avenues show promise for the treatment of bacterial infections and should be further investigated to explore their full potential in the face of a postantibiotic era.
244 citations
TL;DR: This work systematically gives a comprehensive review in current developments of benzimidazole‐based compounds in the whole range of medicinal chemistry as anticancer, antibacterial, antifungal, anti‐inflammatory, analgesic agents, anti-HIV, antioxidant, anticonvulsant, antitubercular, antidiabetic, antileishmanial, antihistaminic, antimalarial agents, and other medicinal agents.
Abstract: The properties of benzimidazole and its derivatives have been studied over more than one hundred years. Benzimidazole derivatives are useful intermediates/subunits for the development of molecules of pharmaceutical or biological interest. Substituted benzimidazole derivatives have found applications in diverse therapeutic areas such as antiulcer, anticancer agents, and anthelmintic species to name just a few. This work systematically gives a comprehensive review in current developments of benzimidazole-based compounds in the whole range of medicinal chemistry as anticancer, antibacterial, antifungal, anti-inflammatory, analgesic agents, anti-HIV, antioxidant, anticonvulsant, antitubercular, antidiabetic, antileishmanial, antihistaminic, antimalarial agents, and other medicinal agents. This review will further be helpful for the researcher on the basis of substitution pattern around the nucleus with an aim to help medicinal chemists for developing an SAR on benzimidazole drugs/compounds.
225 citations
TL;DR: Triazole core is considered as a privileged structure in medicinal chemistry and is widely used as ‘parental’ compounds to synthesize molecules with medical benefits, especially with infection‐related activities and triazole as a potential targeted core moiety against tuberculosis is explored.
Abstract: Tuberculosis is a contagious disease with comparatively high mortality worldwide. The statistics shows that around three million people throughout the world die annually from tuberculosis and there are around eight million new cases each year, of which developing countries showed major share. Therefore, the discovery and development of effective antituberculosis drugs with novel mechanism of action have become an insistent task for infectious diseases research programs. The literature reveals that, heterocyclic moieties have drawn attention of the chemists, pharmacologists, microbiologists, and other researchers owing to its indomitable biological potential as anti-infective agents. Among heterocyclic compounds, triazole (1,2,3-triazole/1,2,4-triazole) nucleus is one of the most important and well-known heterocycles, which is a common and integral feature of a variety of natural products and medicinal agents. Triazole core is considered as a privileged structure in medicinal chemistry and is widely used as ‘parental’ compounds to synthesize molecules with medical benefits, especially with infection-related activities. In the present review, we have collated published reports on this versatile core to provide an insight so that its complete therapeutic potential can be utilized for the treatment of tuberculosis. This review also explores triazole as a potential targeted core moiety against tuberculosis and various research ongoing worldwide. It is hoped that this review will be helpful for new thoughts in the quest for rational designs of more active and less toxic triazole-based antituberculosis drugs.
132 citations
TL;DR: In this paper, the authors investigated curcumin's ability to bind to the amyloid aggregates including oligomers and fibrils, and found that it is able to shift the equilibrium in the aggregation pathway by promoting the formation of non-toxic aggregates.
Abstract: Curcumin, a chemical constituent present in the spice turmeric, is known to prevent the aggregation of amyloid peptide implicated in the pathophysiology of Alzheimer's disease. While curcumin is known to bind directly to various amyloid aggregates, no systematic investigations have been carried out to understand its ability to bind to the amyloid aggregates including oligomers and fibrils. In this study, we constructed computational models of (i) Aβ hexapeptide (16) KLVFFA(21) octamer steric-zipper β-sheet assembly and (ii) full-length Aβ fibril β-sheet assembly. Curcumin binding in these models was evaluated by molecular docking and molecular dynamics (MD) simulation studies. In both the models, curcumin was oriented in a linear extended conformation parallel to fiber axis and exhibited better stability in the Aβ hexapeptide (16) KLVFFA(21) octamer steric-zipper model (Ebinding = -10.05 kcal/mol) compared to full-length Aβ fibril model (Ebinding = -3.47 kcal/mol). Analysis of MD trajectories of curcumin bound to full-length Aβ fibril shows good stability with minimum Cα-atom RMSD shifts. Interestingly, curcumin binding led to marked fluctuations in the (14) HQKLVFFA(21) region that constitute the fibril spine with RMSF values ranging from 1.4 to 3.6 A. These results show that curcumin binding to Aβ shifts the equilibrium in the aggregation pathway by promoting the formation of non-toxic aggregates.
104 citations
TL;DR: VLX1570 was found to inhibit proteasome deubiquitinase activity in vitro in a manner consistent with competitive inhibition and did not show inhibitory activity on a panel of recombinant non‐proteasome DUBs, on recombinant kinases, or on caspase‐3 activity, suggesting that VLx1570 is not an overtly reactive general enzyme inhibitor.
Abstract: The ubiquitin-proteasome system (UPS) is increasingly recognized as a therapeutic target for the development of anticancer therapies. The success of the 20S proteasome core particle (20S CP) inhibitor bortezomib in the clinical management of multiple myeloma has raised the possibility of identifying other UPS components for therapeutic intervention. We previously identified the small molecule b-AP15 as an inhibitor of 19S proteasome deubiquitinase (DUB) activity. Building upon our previous data, we performed a structure-activity relationship (SAR) study on b-AP15 and identified VLX1570 as an analog with promising properties, including enhanced potency and improved solubility in aqueous solution. In silico modeling was consistent with interaction of VLX1570 with key cysteine residues located at the active sites of the proteasome DUBs USP14 and UCHL5. VLX1570 was found to inhibit proteasome deubiquitinase activity in vitro in a manner consistent with competitive inhibition. Furthermore, using active-site-directed probes, VLX1570 also inhibited proteasome DUB activity in exposed cells. Importantly, VLX1570 did not show inhibitory activity on a panel of recombinant non-proteasome DUBs, on recombinant kinases, or on caspase-3 activity, suggesting that VLX1570 is not an overtly reactive general enzyme inhibitor. Taken together, our data shows the chemical and biological properties of VLX1570 as an optimized proteasome DUB inhibitor.
78 citations
TL;DR: It can be suggested that deeper understanding about the CDC42 contribution in cancer cell progression at molecular level can approach to the development of Cdc42 inhibitors in cancer management.
Abstract: Contribution of Cdc42, a member of Rho family, has been characterized for the beginning of variety of cellular responses including cellular transformation, cell division, cell invasion, migration, invadopodia formation, enzyme activity, filopodia formation, and cell polarity in cells. Deregulation of Cdc42 can alter the normal functioning of the cells, responsible for the initiation of signaling pathways and is correlated with several pathogenic processes such as cancer. Therefore, maintaining the level of Cdc42 and its effectors in cells, tumor progression can be controlled. Therefore, it can be suggested that deeper understanding about the Cdc42 contribution in cancer cell progression at molecular level can approach to the development of Cdc42 inhibitors in cancer management.
78 citations
TL;DR: This study aims at introducing cellulose nanocrystals as suitable carriers for drug delivery to skin through dynamic light scattering and atomic force microscopy and shows an approximately sustained release profile of hydroquinone.
Abstract: Nanotechnology-based drug delivery systems can enhance drug permeation through the skin and improve the drug stability. The biodegradability and biocompatibility of cellulose nanocrystals have made these nanoparticles good candidates to use in biomedical applications. The hyperpigmentation is a common skin disorder that could be caused by number of reasons such as sun exposure and pregnancy. Hydroquinone could inhibit the production of melanin and eliminate the discolorations of skin. This study is aimed at introducing cellulose nanocrystals as suitable carriers for drug delivery to skin. Prepared cellulose nanocrystals were characterized by dynamic light scattering and atomic force microscopy. The size of cellulose nanocrystals determined using dynamic light scattering was 301 ± 10 nm. Hydroquinone-cellulose nanocrystal complex was prepared by incubating of hydroquinone solution in cellulose nanocrystals suspension. The size of hydroquinone-cellulose nanocrystal complex determined using dynamic light scattering was 310 ± 10 nm. The hydroquinone content of the hydroquinone-cellulose complex was determined using UV/vis spectroscopy. Hydroquinone was bound to cellulose nanocrystals representing 79.3 ± 2% maximum binding efficiency when 1.1 mg hydroquinone was added to 1 mL of cellulose nanocrystals suspension (2 mg cellulose nanocrystal). The hydroquinone-cellulose nanocrystal complex showed an approximately sustained release profile of hydroquinone. Approximately, 80% of bound hydroquinone released in 4 h.
69 citations
TL;DR: In this article, the specific effect of let-7 microRNAs in particular let7b in hepatic commitment of human adipose tissue-derived mesenchymal stem cells (hAT-MSCs) was evaluated.
Abstract: MicroRNAs are small non-coding RNAs that regulate key processes of the stem cells. Although, microRNAs have emerged as powerful regulators of differentiation, few studies have been focused on the post-transcriptional regulation of hepatic differentiation in mesenchymal stem cells (MSCs) by microRNAs. The aim of this study was to evaluate the specific effect of let-7 microRNAs in particular let-7b in hepatic commitment of human adipose tissue-derived mesenchymal stem cells (hAT-MSCs). The dynamic expression profile of let-7a, b, c microRNAs and two liver-enriched transcription factors (LETFs) HNF4a and HNF6 was studied during in vitro hepatic differentiation of hAT-MSCs. Let-7b was used for transient overexpression and knockdown investigations. It was shown that the expression of LETFs is inversely correlated with those of let-7 miRNAs during differentiation progress (p < 0.05). Inhibition of let-7b caused upregulation of LETFs, an increase in the expression of miR-122 (p < 0.01) emulating the features of functional hepatocytes, and accumulation of hAT-MSCs in the G0 /G1 phase of cell cycle, triggering initiation of hepatic commitment. In conclusion, transient inhibition of let-7b activates hepatic differentiation of hAT-MSCs. The findings of this work might help optimization of in vitro hepatogenic differentiation utilizing microRNAs and hAT-MSCs that could be used for therapeutic purposes.
69 citations
TL;DR: The susceptibility of new therapeutic compounds to the development of resistance, by comparison with known resistance mechanisms observed for classical bacteriostatic or bacteriolytic antibiotics, is discussed by review of available experimental case studies.
Abstract: In view of the relentless increase in antibiotic resistance in human pathogens, efforts are needed to safeguard our future therapeutic options against infectious diseases. In addition to regulatory changes in our antibiotic use, this will have to include the development of new therapeutic compounds. One area that has received growing attention in recent years is the possibility to treat or prevent infections by targeting the virulence mechanisms that render bacteria pathogenic. Antivirulence targets include bacterial adherence, secretion of toxic effector molecules, bacterial persistence through biofilm formation, quorum sensing and immune evasion. Effective small-molecule compounds have already been identified that suppress such processes. In this review, we discuss the susceptibility of such compounds to the development of resistance, by comparison with known resistance mechanisms observed for classical bacteriostatic or bacteriolytic antibiotics, and by review of available experimental case studies. Unfortunately, appearance of resistance mechanisms has already been demonstrated for some, showing that the quest of new, lasting drugs remains complicated.
67 citations
TL;DR: Docking outcomes were in good agreement with in vitro results confirming the dual binding inhibitory activity of compound 10b, and the most potent anti‐acetylcholinesterase activity was shown to be as potent as rivastigmine.
Abstract: In this study, novel acridone-1,2,4-oxadiazole-1,2,3-triazole hybrids were designed, synthesized, and evaluated for their acetylcholinesterase and butyrylcholinesterase inhibitory activity. Among various synthesized compounds, 10-((1-((3-(4-methoxyphenyl)-1,2,4-oxadiazol-5-yl)methyl)-1H-1,2,3-triazol-4-yl)methyl)acridin-9(10H)-one 10b showed the most potent anti-acetylcholinesterase activity (IC50 = 11.55 μm) being as potent as rivastigmine. Also docking outcomes were in good agreement with in vitro results confirming the dual binding inhibitory activity of compound 10b.
58 citations
TL;DR: Six semi‐synthetic derivatives of ursolic acid may find their potential use as synergistic agents in the treatment of multidrug‐resistant Gram‐negative infections.
Abstract: As a part of our drug discovery program, ursolic acidwas chemically transformed into six semi-syntheticderivatives, which were evaluated for their antibacterialand drug resistance reversal potential in combinationwith conventional antibiotic nalidixic acid against thenalidixic acid-sensitive and nalidixic acid-resistantstrains of Escherichia coli. Although ursolic acidand its all semi-synthetic derivatives did not showantibacterial activity of their own, but in combination,they significantly reduced the minimum inhibitoryconcentration of nalidixic acid up to eightfold. The3-O-acetyl-urs-12-en-28-isopropyl ester (UA-4) and3-O-acetyl-urs-12-en-28-n-butyl ester (UA-5) deriva-tives of ursolic acid reduced the minimum inhibitoryconcentration of nalidixic acid by eightfold againstnalidixic acid-resistant and four and eightfold againstnalidixic acid-sensitive, respectively. The UA-4 andUA-5 were further evaluated for their synergy potentialwith another antibiotic tetracycline against the multi-drug-resistant clinical isolate of Escherichia coli-KG4.The results showed that both these derivatives in com-bination with tetracycline reduced the cell viability inconcentration-dependent manner by significantly inhib-iting efflux pump. This was further supported by the insilico binding affinity of UA-4 and UA-5 with effluxpump proteins. These ursolic acid derivatives may findtheir potential use as synergistic agents in the treat-ment of multidrug-resistant Gram-negative infections.Key words: ester analog, multidrug-resistant, nalidixic acid,non-antibiotics, tetracycline, triterpenoidsReceived 27 May 2014, revised 1 December 2014 andaccepted for publication 1 December 2014
TL;DR: A series of new derivatives of N‐(2‐methoxyphenyl)piperazine have been synthesized for their affinity toward serotonergic receptors and for their potential antidepressant‐like activity, with the most promising compound exhibiting affinity toward receptors Ki <1 nm (5‐HT1A) and Ki = 34 nm ( 5‐HT7).
Abstract: A series of new derivatives of N-(2-methoxyphenyl)piperazine have been synthesized for their affinity toward serotonergic receptors and for their potential antidepressant-like activity. They have been evaluated toward receptors 5-HT1A , 5-HT6 , and 5-HT7 , as well as in vivo in the tail suspension, locomotor activity, and motor co-ordination tests. All the tested compounds proved very good affinities toward 5-HT1A and 5-HT7 receptors. The most promising compound was 1-[(2-chloro-6-methylphenoxy)ethoxyethyl]-4-(2-methoxyphenyl)piperazine hydrochloride, exhibiting affinity toward receptors Ki <1 nm (5-HT1A ) and Ki = 34 nm (5-HT7 ). Antidepressant-like activity (tail suspension test) was observed at 2.5 mg/kg b.w. (mice, i.p.), and the effect was stronger than that observed for imipramine (5 mg/kg b.w.). Sedative activity was observed at ED50 (locomotor test, mice, i.p.) = 17.5 mg/kg b.w. and neurotoxicity was observed at TD50 (rotarod, mice, i.p.) = 53.2 mg/kg b.w.
TL;DR: T3SS activity is regulated by its interaction with biologically relevant molecules, such as bile salts and sterols, which could serve as scaffolds for drug design as well as chemically and structurally diverse classes of small molecule inhibitors of the T3SS.
Abstract: Antibiotic resistance in pathogens requires new targets for developing novel antibacterials. The bacterial type III secretion system (T3SS) is an attractive target for developing antibacterials as it is essential in the pathogenesis of many Gram-negative bacteria. The T3SS consists of structural proteins, effectors, and chaperones. Over 20 different structural proteins assemble into a complex nanoinjector that punctures a hole on the eukaryotic cell membrane to allow the delivery of effectors directly into the host cell cytoplasm. Defects in the assembly and function of the T3SS render bacteria non-infective. Two major classes of small molecules, salicylidene acylhydrazides and thiazolidinones, have been shown to inhibit multiple genera of bacteria through the T3SS. Many additional chemically and structurally diverse classes of small molecule inhibitors of the T3SS have been identified as well. While specific targets within the T3SS of a few inhibitors have been suggested, the vast majority of specific protein targets within the T3SS remain to be identified or characterized. Other T3SS inhibitors include polymers, proteins, and polypeptides mimics. In addition, T3SS activity is regulated by its interaction with biologically relevant molecules, such as bile salts and sterols, which could serve as scaffolds for drug design.
TL;DR: Results show that aurones, which had not been previously reported as MAOi, are MAO‐B inhibitors, and both families inhibited selectively the B isoform of MAO in the micromolar range, offering novel scaffolds for the design of new and potent MAO inhibitors.
Abstract: A series of chalcones and aurones were synthesized and evaluated in vitro as monoamine oxidase inhibitors (MAOi). Our results show that aurones, which had not been previously reported as MAOi, are MAO-B inhibitors. Thus, both families inhibited selectively the B isoform of MAO in the micromolar range, offering novel scaffolds for the design of new and potent MAO inhibitors. The main structural requirements for their activity were characterized with the aid of 3D-QSAR and docking studies.
TL;DR: It is shown that miR‐9, by direct targeting of NOTCH1, can reveal a suppressor‐like activity in metastatic breast cancer cells, and it is possible to inhibit metastasis and induce pro‐apoptotic state by induction of miR-9 expression in MDA‐MB‐231 cells but with no effect on cell proliferation.
Abstract: Many reports have indicated deregulation of a variety of microRNAs (miRNAs) in human cancers. In this study, we appraised miR-9 correlation with NOTCH1 involved in Notch signaling in metastatic breast cancer. The Notch signaling pathway has been approved to be associated with the development and progression of many human cancers, including breast cancer, but the precise mechanism has remained unknown. To the best of our knowledge, this is the first study that introduces miR-9 and NOTCH1 correlation as an effective factor in breast cancer. We found that miR-9 expression was decreased in MDA-MB-231 breast cancer cells compared with MCF-10A normal breast cell line. However, NOTCH1 was upregulated in the metastatic breast cancer cells. Furthermore, luciferase assay revealed a significant inverse correlation between miR-9 and NOTCH1. Overexpression of Notch signaling via Notch1 intracellular domain in MDA-MB-231 cell line was suppressed by lentiviruses expressing miR-9. Taken together, the results obtained by MTT, flow cytometry, migration, and wound healing assays showed that it is possible to inhibit metastasis and induce pro-apoptotic state by induction of miR-9 expression in MDA-MB-231 cells but with no effect on cell proliferation. These results shows that miR-9, by direct targeting of NOTCH1, can reveal a suppressor-like activity in metastatic breast cancer cells.
TL;DR: Five N‐methyl‐N‐R‐N,N‐bis(2‐hydroxyethyl) ammonium bromides were prepared based on N‐methyldiethanolamine (MDEA) and halohydrocarbon and provided a facile way to design and develop new types of antibacterial drugs for application in preventing the fruit rot, especially apple.
Abstract: Five N-methyl-N-R-N,N-bis(2-hydroxyethyl) ammonium bromides (R = -benzyl (chloride, BNQAS), -dodecyl (C12QAS), -tetradecyl (C14QAS), -hexadecyl (C16QAS), -octadecyl (C18QAS)) were prepared based on N-methyldiethanolamine (MDEA) and halohydrocarbon. Five QAS were characterized by FTIR, NMR, and MS. BNQAS, C12QAS, C14QAS, and C16QAS were confirmed by X-ray single-crystal diffraction. Their antibacterial properties indicated good antibacterial abilities against E. coli, S. aureus, B. subtilis, especially C12QAS with the best antibacterial ability (100% to E. coli, 95.65% to S. aureus, and 91.41% to B. subtilis). In addition, C12QAS also displayed the best antifungal activities than BNQAS and C18QAS against Cytospora mandshurica, Botryosphaeria ribis, Physalospora piricola, and Glomerella cingulata with the ratio of full marks. The strategy provides a facile way to design and develop new types of antibacterial drugs for application in preventing the fruit rot, especially apple.
TL;DR: This work suggests that 6m and 6q suppressed the lipopolysaccharide‐induced acute lung injury through inhibition of the inflammatory response in vivo and in vitro, indicating that quinazolines might serve as potential agents for the treatment of acute lung Injury and deserve the continuing drug development and research.
Abstract: Quinazoline has been reported to exhibit multiple bioactivities. The aim of this study was to discover new quinazoline derivatives with preventive effect on lipopolysaccharide-induced acute lung injury via anti-inflammatory actions. Thirty-three 4-amino quinazolin derivatives were synthesized and screened for anti-inflammatory activities in lipopolysaccharide-induced macrophages. The most potent four compounds, 6h, 6m, 6p, and 6q, were shown dose-dependent inhibition against lipopolysaccharide-induced TNF-α and IL-6 release. Then, the preliminary structure-activity relationship and quantitative structure-activity relationship analyses were conducted. To further determine the effects of quinazolines on acute lung injury treatment, lipopolysaccharide-induced acute lung injury model was employed. Male Sprague Dawley rats were pretreated with 6m or 6q before instillation of lipopolysaccharide. The results showed that 6m and 6q, especially 6q, obviously alleviated lung histopathological changes, inflammatory cells infiltration, and cytokines mRNA expression initiated by lipopolysaccharide. Taken together, this work suggests that 6m and 6q suppressed the lipopolysaccharide-induced acute lung injury through inhibition of the inflammatory response in vivo and in vitro, indicating that quinazolines might serve as potential agents for the treatment of acute lung injury and deserve the continuing drug development and research.
TL;DR: The interactions between compounds 8b, Cu2+ ion, and MRSA DNA revealed that compound 8b could intercalate into DNA through copper ion bridge to form a steady 8b–Cu2+–DNA ternary complex which might further block DNA replication to exert the powerful bioactivities.
Abstract: A novel series of quinolone imidazoles as new type of antimicrobial agents were synthesized. Most compounds exhibited good bioactivities especially against MRSA even superior to reference drugs. They induced bacterial resistance more slowly than clinical drugs and gave low cytotoxicity to human cells. The pKa values of these compounds showed appropriate ranges to pharmacokinetic behaviors. The interactions between compound 8b, Cu(2+) ion, and MRSA DNA revealed that compound 8b could intercalate into DNA through copper ion bridge to form a steady 8b-Cu(2+) -DNA ternary complex which might further block DNA replication to exert the powerful bioactivities. Study of compound 8b with human serum albumin indicated that compound 8b could be effectively stored and carried by human serum albumin.
TL;DR: In this article, 13 novel ursolic acid derivatives were designed and synthesized in an attempt to further improve compound potency, and the structures of newly synthesized compounds were confirmed using mass spectrometry, infrared spectroscopy, and H NMR.
Abstract: Ursolic acid (UA) is a natural product which has been shown to possess a wide range of pharmacological activities, in particular those with anticancer activity. In this study, 13 novel ursolic acid derivatives were designed and synthesized in an attempt to further improve compound potency. The structures of the newly synthesized compounds were confirmed using mass spectrometry, infrared spectroscopy, and (1) H NMR. The ability of the UA derivatives to inhibit cell growth was assayed against both various tumor cell lines and a non-pathogenic cell line, HELF. Analysis of theoretical toxicity risks for all derivatives was performed using OSIRIS and indicated that the majority of compounds would present moderate to low risks. Pharmacological results indicated that the majority of the derivatives were more potent growth inhibitors than UA. In particular, 5b demonstrated IC50 values ranging from 4.09 ± 0.27 to 7.78 ± 0.43 μm against 12 different tumor cell lines. Flow cytometry analysis indicated that 5b induced G0/G1 arrest in three of these cell lines. These results were validated by structural docking studies, which confirmed that UA could bind to cyclins D1 (Cyc D1) and cyclin-dependent kinases (CDK6), the key regulators of G0/G1 transition in cell cycle, while the piperazine moiety of 5b could bind with glucokinase (GK), glucose transporter 1 (GLUT1), and ATPase, which are the main proteins involved in cancer cell metabolism. Acridine orange/ethidium bromide staining confirmed that 5b was capable of inducing apoptosis and decreasing cell viability in a dose-dependent manner.
TL;DR: A series of 4‐hydroxycoumarin‐derived compounds 8a‐p containing N‐benzyl‐1,2,3‐triazole motif were designed as A ChE inhibitors and 2‐chlorobenzyl derivative 8k showed the most potent activity against AChE.
Abstract: A series of 4-hydroxycoumarin-derived compounds 8a-p containing N-benzyl-1,2,3-triazole motif were designed as AChE inhibitors. The title compounds were obtained conveniently using multicomponent click reaction. The in vitro anticholinesterase evaluation of synthesized compounds against AChE and BuChE showed that some of them are potent and selective inhibitors of AChE. Among them, 2-chlorobenzyl derivative 8k showed the most potent activity against AChE (IC50 = 0.18 μm). Its activity was also superior to that of standard drug tacrine. The kinetic study and molecular docking simulation of the most potent compound 8k were also described.
TL;DR: Two machine‐learning techniques, neural networks and decision trees, that have been used to identify experimentally validated antibiotics are described, and the future directions of this exciting field are described.
Abstract: The emergence of drug-resistant bacteria threatens to revert humanity back to the preantibiotic era. Even now, multidrug-resistant bacterial infections annually result in millions of hospital days, billions in healthcare costs, and, most importantly, tens of thousands of lives lost. As many pharmaceutical companies have abandoned antibiotic development in search of more lucrative therapeutics, academic researchers are uniquely positioned to fill the pipeline. Traditional high-throughput screens and lead-optimization efforts are expensive and labor intensive. Computer-aided drug-discovery techniques, which are cheaper and faster, can accelerate the identification of novel antibiotics, leading to improved hit rates and faster transitions to preclinical and clinical testing. The current review describes two machine-learning techniques, neural networks and decision trees, that have been used to identify experimentally validated antibiotics. We conclude by describing the future directions of this exciting field.
TL;DR: Results can guide the development of new drugs against leishmaniasis based on [1,2,4]triazolo[1,5‐a]pyrimidine derivatives targeting the arginase enzyme, which seems to be a potential drug target for Leishmania treatment.
Abstract: Arginase is a glycosomal enzyme in Leishmania that is involved in polyamine and trypanothione biosynthesis The central role of arginase in Leishmania (Leishmania) amazonensis was demonstrated by the generation of two mutants: one with an arginase lacking the glycosomal addressing signal and one in which the arginase-coding gene was knocked out Both of these mutants exhibited decreased infectivity Thus, arginase seems to be a potential drug target for Leishmania treatment In an attempt to search for arginase inhibitors, 29 derivatives of the [1,2,4]triazolo[1,5-a]pyrimidine system were tested against Leishmania (Leishmania) amazonensis arginase in vitro The [1,2,4]triazolo[1,5-a]pyrimidine scaffold containing R1 = CF3 exhibited greater activity against the arginase rather than when the substituent R1 = CH3 in the 2-position The novel compound 2-(5-methyl-2-(trifluoromethyl)-[1,2,4]triazolo[1,5-a]pyrimidin-7-yl)hydrazinecarbothioamide (30) was the most potent, inhibiting arginase by a non-competitive mechanism, with the Ki and IC50 values for arginase inhibition estimated to be 17 ± 1 μm and 165 ± 05 μm, respectively These results can guide the development of new drugs against leishmaniasis based on [1,2,4]triazolo[1,5-a]pyrimidine derivatives targeting the arginase enzyme
TL;DR: The exciting pH‐dependent release properties of doxorubicin‐loaded Fe3O4@mSiO2 NPs make their use a promising strategy for enhancing efficient therapy toward tumors, while reducing the cytotoxicity ofDoxorUBicin to human normal neutral tissue or cells.
Abstract: The facile synthesis of core-shell magnetic mesoporous silica nanoparticles (Fe3 O4 @mSiO2 NPs) was reported in aqueous phase using cetyltrimethylammonium bromide as a template under alcohol-free conditions. Compared to the conventional synthesis method for core-shell Fe3 O4 @mSiO2 NPs, the approach in this study is rapid (only 5-min reaction time), cheap (without using organic agents), and environmentally friendly (one-step synthesis in alcohol-free medium). Doxorubicin (DOX)-loaded Fe3 O4 @mSiO2 NPs exert extraordinarily high specificity for liver cancer cells, which was due to the pH-sensitive doxorubicin release, as well as higher endocytosis capacity in liver cancer cells rather than normal liver cells. The potential advantages of using such Fe3 O4 @mSiO2 NPs as the vehicle of anticancer drugs were that the Fe3 O4 @mSiO2 NPs exhibit good biocompatibility, high loading and protection of the guest molecules, selective killing effect, and efficient cellular uptake. The exciting pH-dependent release properties of doxorubicin-loaded Fe3 O4 @mSiO2 NPs make their use a promising strategy for enhancing efficient therapy toward tumors, while reducing the cytotoxicity of doxorubicin to human normal neutral tissue or cells.
TL;DR: The results suggest that this novel class of indole–pyrimidine‐containing piperazine moiety may have potential to be developed as new a class of tubulin polymerization inhibitors.
Abstract: A series of novel hybrids of indole-pyrimidine-containing piperazine moiety were designed, synthesized and evaluated for their antiproliferative and tubulin polymerization inhibitory activities. The results indicated that most of these compounds possessed significant cytotoxic potency against four cancer cell lines, HT-29, A549, MDA-MB-231 and MCF-7. Particularly, the most promising compound 34 showed more potent and broad-spectrum cytotoxic activities with the IC50 values ranged from 5.01 to 14.36 μm against A549, MDA-MB-231 and MCF-7 cell lines. Meanwhile, 34 also displayed the most potent tubulin polymerization inhibitory activity with IC50 value of 11.2 μm. Furthermore, molecular docking analysis demonstrated 34 interacts and binds efficiently with the tubulin protein at the colchicine-binding site. It was worth noting that the compound did not affect the normal human embryonic kidney cells, HEK-293. These results suggest that this novel class of indole-pyrimidine hybrids may have potential to be developed as new a class of tubulin polymerization inhibitors.
TL;DR: The results indicate the effective and selective action of AMQ‐j against L. amazonensis, and its mechanism of action appears to be mediated by mitochondrial dysfunction associated with ROS production.
Abstract: The leishmanicidal activity of a series of 4-aminoquinoline (AMQ) derivatives was assayed against Leishmania amazonensis. This activity against the intracellular parasite was found stronger than for L. amazonensis promastigotes. Neither compound was cytotoxic against macrophages. The compound AMQ-j, which exhibited a strong activity against promastigotes and amastigotes of L. amazonensis (IC50 values of 5.9 and 2.4 μg/mL, respectively) and similar leishmanicidal activity to reference drugs, was chosen for studies regarding its possible mechanism of action toward parasite death. The results showed that the compound AMQ-j induced depolarization of the mitochondrial membrane potential in promastigotes and in L. amazonensis-infected macrophages, but not in uninfected macrophages. Furthermore, the depolarization of the mitochondrial membrane potential was dose dependent in infected macrophages. We have established that promastigotes and L. amazonensis-infected macrophages treated with AMQ-j were submitted to oxidative stress. This is in line with the increase in the level of reactive oxygen species (ROS). Leishmania amazonensis-infected macrophages treated with AMQ-j did not show a significant increase in the production of nitric oxide. Our results indicate the effective and selective action of AMQ-j against L. amazonensis, and its mechanism of action appears to be mediated by mitochondrial dysfunction associated with ROS production.
TL;DR: New Mannich base‐type eugenol derivatives were synthesized and evaluated for their anticandidal activity using a broth microdilution assay, and 4‐allyl‐2‐methoxy‐6‐(morpholin‐4‐ylmethyl) phenyl benzoate and 8 were found to be the most effective antifungal compounds with low IC50 values.
Abstract: New Mannich base-type eugenol derivatives were synthesized and evaluated for their anticandidal activity using a broth microdilution assay. Among the synthesized compounds, 4-allyl-2-methoxy-6-(morpholin-4-ylmethyl) phenyl benzoate (7) and 4-{5-allyl-2-[(4-chlorobenzoyl)oxy]-3-methoxybenzyl}morpholin-4-ium chloride (8) were found to be the most effective antifungal compounds with low IC50 values, some of them well below those of reference drug fluconazole. The most significant IC50 values were those of 7 against C. glabrata (1.23 μm), C. albicans and C. krusei (both 0.63 μm). Additionally, the synthesized compounds were evaluated for their in vitro cytotoxic effects on human mononuclear cells. As result, the cytotoxic activity of eugenol in eukaryotic cells decreased with the introduction of the morpholinyl group. Given these findings, we point out compounds 7 and 8 as the most promising derivatives because they showed potency values greater than those of eugenol and fluconazole and they also presented high selectivity indexes.
TL;DR: Evaluating the physico‐chemical stability of bLf‐loaded liposomes and solid lipid particles (SLPs) modified by pectin and chitosan when exposed to various stress conditions concluded that SLPs are considered as primary choice for oral bLF delivery.
Abstract: A critical problem associated with delivery of bovine lactoferrin (bLf) by the oral route is low bioavailability, which is derived from the enzymatic degradation in the gastrointestinal tract and poor permeation across the intestinal epitheliums. Particulate carrier systems have been identified to protect bLf against proteolysis via encapsulation. This study aimed to evaluate the physico-chemical stability of bLf-loaded liposomes and solid lipid particles (SLPs) modified by pectin and chitosan when exposed to various stress conditions. Transmission electron microscopy results showed liposomes and SLPs had a classic shell-core structure with polymer layers surrounded on surface, but the structure appeared to be partially broken after digestion in simulated intestinal fluid (SIF). Although HPLC and sodium dodecyl sulphate-polyacrylamide gel electrophoresis methods qualitatively and quantitatively described either liposomes or SLPs could retain intact bLf against proteolysis in SIF to some extent, all liposome formulations showed rapid rate of lipolysis mediated by pancreatic enzymes. On the other hand, all SLP formulations showed higher heat resistance and greater electrolyte tolerance compared to liposome formulations. After 180 days storage time, liposome-loaded bLf was completely degraded, whereas almost 30% of intact bLf still remained in SLP formulations. Overall, SLPs are considered as primary choice for oral bLf delivery.
TL;DR: To understand binding characterization of non‐steroidal anti‐inflammatory drugs to HSA, HSA‐palmitic acid–diclofenac structure reveals two distinct binding sites for three dicl ofenac in HSA.
Abstract: Human serum albumin (HSA) is the most abundant protein in plasma, which plays a central role in drug pharmacokinetics because most compounds bound to HSA in blood circulation. To understand binding characterization of non-steroidal anti-inflammatory drugs to HSA, we resolved the structure of diclofenac and HSA complex by X-ray crystallography. HSA-palmitic acid-diclofenac structure reveals two distinct binding sites for three diclofenac in HSA. One diclofenac is located at the IB subdomain, and its carboxylate group projects toward polar environment, forming hydrogen bond with one water molecule. The other two diclofenac molecules cobind in big hydrophobic cavity of the IIA subdomain without interactive association. Among them, one binds in main chamber of big hydrophobic cavity, and its carboxylate group forms hydrogen bonds with Lys199 and Arg218, as well as one water molecule, whereas another diclofenac binds in side chamber, its carboxylate group projects out cavity, forming hydrogen bond with Ser480.
TL;DR: This work designs the first ω‐conotoxin/opioid peptidomimetics based on the enkephalin‐like sequence Tyr‐D‐Ala‐Gly‐Phe and two fragments derived from the loop‐2 pharmacophore of ω-conot toxin MVIIA, with the aim of developing new multitarget analgesic compounds.
Abstract: N-type voltage-dependent Ca(2+) channels (CaV 2.2) are located at nerve endings in the central and peripheral nervous systems and are strongly associated with the pathological processes of cerebral ischaemia and neuropathic pain. CaV 2.2 blockers such as the ω-conotoxin MVIIA (Prialt) are analgesic and have opioid-sparing effects. With the aim to develop new multitarget analgesic compounds, we designed the first ω-conotoxin/opioid peptidomimetics based on the enkephalin-like sequence Tyr-D-Ala-Gly-Phe (for the opioid portion) and two fragments derived from the loop-2 pharmacophore of ω-conotoxin MVIIA. Antinociceptive activity evaluated in vitro and in vivo revealed differential affinity for CaV 2.2 and opioid receptors and no significant synergistic activity.
TL;DR: This review covers recent developments in the screening and testing of new anti‐infective compounds that interfere with aspects of bacterial pathogenicity, so‐called antivirulence approach.
Abstract: There is an urgent requirement for new anti-infective compounds that can be used to prevent or treat bacterial pathogens. In particular, Gram-negative pathogens, which are most commonly associated with hospital-acquired infections, are of major concern. In this review, we cover recent developments in the screening and testing of new anti-infective compounds that interfere with aspects of bacterial pathogenicity. This so-called antivirulence approach is very different to traditional antibiotic development and testing. Moreover, antivirulence compounds vary considerably in their chemical structures, ranging from small compounds to large natural products. The challenge of understanding the precise mechanism of action of any such compound is also highlighted.