Series Of Analogues Research Articles

Discovery of Dual TRPA1 and TRPV1 Antagonists as Novel Therapeutic Agents for Pain.

Pain management remains a major challenge in medicine, highlighting the need for the development of new therapeutic agents. The transient receptor potential ankyrin 1 (TRPA1) and vanilloid 1 (TRPV1) are ion channels that play key roles in pain perception. Targeting both TRPA1 and TRPV1 simultaneously with dual antagonists offers a promising approach to pain relief. In this study, we investigated a series of hybrid analogs of TRPA1 and TRPV1 antagonists to discover novel therapeutic agents for pain. Among these compounds synthesized by a condensation reaction forming 1,2,4-oxadiazole between the A- and C-regions, compound 50 exhibited substantial dual-acting antagonism to TRPA1 and TRPV1 with IC50 values of 1.42, 2.84, 2.13, and 5.02 μM for hTRPA1, mTRPA1, hTRPV1, and rTRPV1, respectively. In the formalin test, compound 50 demonstrated dose-dependent analgesic activity with an ED50 of 85.9 mg/kg in phase 1 and 21.6 mg/kg in phase 2, respectively, and was able to inhibit pain behavior completely at a dose of 100 mg/kg. This study presents the discovery and characterization of a novel dual TRPA1/TRPV1 antagonist, highlighting its potential as a therapeutic agent for pain management.

Structural and biological studies on beta – alanine substituted Sulfonamide derivatives: A new class of Juvenile hormone mimics as insect growth regulators

A series of naphthyl-sulfonamide juvenile hormone analogs has been synthesized through one-pot synthesis route using thionyl chloride as an activating agent for carboxylic functional group. The structures of synthesized compounds with general formula C10H7-SO2NH-(CH2)2CON-R1R2 have been confirmed by FT-IR, 1HNMR , 13CNMR , and ESI-MS techniques. The insect growth regulating property of all the synthesized compounds as juvenile hormone analogs (JHAs) has been studied against yellow fever mosquito, Aedes aegypti and tobacco cutworm, Spodoptera litura. The bioassay results demonstrate that the synthesized compounds exhibit insect growth regulating activity in comparison to standard JHAs. The IE50 and IE90 values of B4 are 0.08 and 6.62 ppm, respectively for inhibition of Aedes aegypti and the LC50 and LC90 values of B3 are 11.03 and 45.36 ppm, respectively for Spodoptera litura. Notably, the compounds B3 and B4 showed enhanced efficacy at lower concentrations. Additionally, density functional theory (DFT) technique is used to predict the chemical reactivity and toxicity of the synthesized JHAs in comparison to pyriproxyfen. Further, the DNA-binding study of synthesized JHAs has been carried out using UV–vis spectroscopy for toxicity assessment against DNA and the binding constant values in the range 102 – 103 suggest lower toxicity of all the synthesized molecules in comparison to PYR. All the synthesized JHAs show IGR action and exhibit better reactivity and reduced toxicity as compared to the commercial in use IGRs.

In-Vitro and In-Silico Studies of Brevifoliol Ester Analogues against Insulin Resistance Condition.

Brevifoliol is a diterpenoid that occurs naturally in the plants of Taxus genus and is widely used as chemotherapy agent for the management of cancer. A series of semisynthetic esters analogues of brevifoliol were prepared by Steglich esterification and attempted for their pharmacological potential against insulin resistance conditions using in-vitro and in-silico assays. The aim of this study is to understand the pharmacological potential of eighteen semisynthetic analogs through Steglich esterification of Brevifoliol against insulin resistance condition Methods: In the in-vitro study, insulin resistance condition was induced in skeletal muscle cells using TNF-α, pro-inflammatory cytokine and these cells were treated with brevifoliol analogues. The most potent analouge was further validated using in-silico docking study against the tumor necrosis factor (TNF-α) (PDB ID: 2AZ5) and Human Insulin Receptor (PDB ID: 1IR3), using the Auto dock Vina v0.8 program. Although, all the analogues of Brevifoliol significantly exhibited the pharmacological potential. Among all, analogue 17 was most potent in reversing the TNF-α induced insulin resistance condition in skeletal muscle cells and also to inhibit the production of TNF-α in LPSinduced inflammation in macrophage cells in a dose-dependent manner. Similarly, in-silico molecular docking studies revealed that analogue 17 possesses a more promising binding affinity than the selected control drug metformin toward the TNF-α and insulin receptor. These findings suggested the suitability of analogue 17 as a drug-like candidate for further investigation toward the management of insulin resistance conditions.

Flexible 2,4-diaminopyrimidine bearing a butyrolactone as Plasmodium falciparum dihydrofolate reductase inhibitors

Recently, P218, a new flexible antifolate targeting Plasmodium falciparum dihydrofolate reductase (PfDHFR), has entered its clinical trial with good safety profile and effective Pf infection prevention. However, it carries a free carboxyl terminal, which is hydrophilic and prone to metabolic glucuronidation. Here, a new series of P218 analogues carrying butyrolactone has been synthesized with the purpose of enhancing lipophilicity and minimizing metabolic instability. The inhibition constants against the mutant PfDHFR enzymes are in sub-nanomolar level and the antimalarial activity against antifolate-resistant parasites are in the low micromolar range. The crystal structure of the most potent analogue LA1 bound enzyme complex indicates interaction with multiple residues, including Arg122 and Phe116 in the active site. In vitro log D7.4 and kinetic solubility confirmed a higher lipophilicity of this butyrolactone series as compared to P218. These outcomes suggest the possibility to further develop butyrolactone derivatives as non-carboxyl antiplasmodial antifolates.

An Integrative Computational Approach for Design and Evaluation of Novel [1,2,4]triazolo[3,4-b][1,3,4]thiadiazole Analogues as Dual-Action Anti-Retroviral and Anti-Bacterial Agents: Insights into Rational Drug Design Strategies

The development of effective antiretroviral inhibitors (HIV-1 Reverse Transcriptase) and glucosamine-6-phosphate (GlcN6P) agents represent a significant challenge for combating viral infections and related diseases. In this study, we employed a multidisciplinary approach to design and evaluate a series of novel triazole analogs as potential candidates for anti-retroviral and glucosamine-6-phosphate agents. Using molecular docking, we explored the binding interactions between the RSA3 analog and the target proteins implicated in viral replication and glucosamine metabolism. Density functional theory (DFT) employing the 6-311++G(d,p) basis set was utilized for computational analysis, with a subsequent examination of the electronic parameters. The HOMO and LUMO orbitals as well as the molecular electrostatic potential map were investigated using DFT to characterize the reactivity of our molecule. Molecular dynamics simulations were performed to investigate the stability and dynamic behavior of the ligand-protein complex (RSA3) over time (300 ns). Furthermore, we employed MM-GBSA calculations of the compound RSA3 (molecular mechanics generalized band surface area) to estimate the binding free energies (−71.30 ± 7.26 kcal/mol and −67.86 ± 7.09 kcal/mol, respectively) and identified the most promising compounds with high affinity for the target proteins. Additionally, predictive absorption, distribution, metabolism, excretion and toxicity (ADMET) studies of compound RSA3 were conducted to assess its drug-like properties and potential safety profiles of the selected compound. Our results revealed that RSA3 has favorable binding interactions, is a stable complex and has significant binding affinity for target proteins. Moreover, predictive ADMET studies indicated that RSA3 possesses desirable drug-like properties, suggesting its potential for further investigation as an anti-retroviral agent and glucosamine-6-phosphate agent. Overall, this integrative computational approach combining molecular docking, DFT analysis, dynamics simulations, MM-GBSA and predictive ADMET studies provides valuable insights into the design and evaluation of novel triazole analogs with potential therapeutic applications, highlighting the importance of rational drug design strategies in the field of antiretroviral and glucosamine research.

Synthesis, insecticidal evaluation, crystal structure and theoretical calculations of nine/ten-membered carbon bridged neonicotinoid analogues

Neonicotinoid insecticides acting on the insect nicotinic acetylcholine receptors (nAChRs) played an essential role in contemporary pest control. The development of pesticide resistance due to frequent pesticide use had made it increasingly difficult to control pests. In order to explore neonicotinoid insecticide with low cross-resistance and higher potency, larger carbon bridge compounds were constructed by introducing cyclohexanone and cycloheptene in accordance with our previous research. A series of novel neonicotinoid analogues with nine/ten-membered carbon bridge were designed and synthesized, which exhibited a range of insecticidal activities. The results indicated that some the target compounds showed good insecticidal activities against Bemisia tabaci and Aphis gossypii at 100 ppm. In particular, the activities of compounds A1 and A10 reached 90 % and 97 % respectively, which were similar to that of the control group. Density Functional Theory (DFT) calculations were used to explain the differences in the insecticidal activities of compounds A10, A11, and A12 against Bemisia tabaci. The lowest LUMO energy (ELUMO) of compound A11 (-1.56 eV) might lead to its reduced insecticidal activities. The present study might be meaningful for directing the design of carbon bridged neonicotinoid analogues.

An insight into the role of ESIPT/TICT-based antioxidant flavone analogues in fluoro-probing diabetes-induced viscosity changes: a unified experimental and theoretical endeavour.

Potent antioxidants, like 3-hydroxy flavones, attracted considerable attention due to their excited state intramolecular proton transfer (ESIPT)-based fluorescence behaviour. This article is an interesting demonstration of a series of synthetic 3-hydroxy flavone analogues having high antioxidant activity as molecular rotor-like viscosity probes. Among these flavone analogues, 4'-N,N-dimethylamino-3-hydroxy flavone (3) is the most potent one, showing the twisted intramolecular charge transfer (TICT)-dependent fluoroprobing activity toward the blood viscosity changes associated with diabetes and free fatty acids (FFA)-induced nuclear viscosity changes of MIN6 cells. The TICT dynamics of (3), which instigates its viscosity probing activity, was comprehended with the help of DFT-based computational studies. Abnormal cellular viscosity changes are the pathological traits for various diseases, and non-toxic flavone-based viscosity probes can be useful for diagnosing such pathological conditions.

Fatty acid derivatization and cyclization of the immunomodulatory peptide RP-182 targeting CD206high macrophages improves anti-tumor activity.

As tumor-associated macrophages (TAMs) exercise a plethora of pro-tumor and immune evasive functions, novel strategies targeting TAMs to inhibit tumor progression have emerged within the current arena of cancer immunotherapy. Activation of the mannose receptor 1 (Mrc1; CD206) is a recent approach that recognizes immune suppressive CD206high M2-like TAMs as a drug target. Ligation of CD206 both induces reprogramming of CD206high TAMs towards a pro-inflammatory phenotype and selectively triggers apoptosis in these cells. CD206-activating therapeutics are currently limited to the linear, 10mer peptide RP-182, 1, which is not a drug candidate. Here we sought to identify a better suitable candidate for future clinical development by synthesizing and evaluating a series of RP-182 analogues. Surprisingly, fatty acid derivative 1a (RP-182-PEG3-K(palmitic acid)) not only showed improved stability but also increased affinity to the CD206 receptor through enhanced interaction with a hydrophobic binding motif of CD206. Peptide 1a showed superior in vitro activity in cell-based assays of macrophage activation which was restricted to CD206high M2-polarized macrophages. Improvement of responses was disproportionally skewed towards improved induction of phagocytosis including cancer cell phagocytosis. 1a reprogrammed the immune landscape in genetically engineered murine KPC pancreatic tumors towards increased innate immune surveillance and improved tumor control, and effectively suppressed tumor growth of murine B16 melanoma allografts.

A Novel Confocal Scanning Protein-Protein Interaction Assay (PPI-CONA) Reveals Exceptional Selectivity and Specificity of CC0651, a Small Molecule Binding Enhancer of the Weak Interaction between the E2 Ubiquitin-Conjugating Enzyme CDC34A and Ubiquitin.

Protein-protein interactions (PPIs) are some of the most challenging target classes in drug discovery. Highly sensitive detection techniques are required for the identification of chemical modulators of PPIs. Here, we introduce PPI confocal nanoscanning (PPI-CONA), a miniaturized, microbead based high-resolution fluorescence imaging assay. We demonstrate the capabilities of PPI-CONA by detecting low affinity ternary complex formation between the human CDC34A ubiquitin-conjugating (E2) enzyme, ubiquitin, and CC0651, a small molecule enhancer of the CDC34A-ubiquitin interaction. We further exemplify PPI-CONA with an E2 enzyme binding study on CC0651 and a CDC34A binding specificity study of a series of CC0651 analogues. Our results indicate that CC0651 is highly selective toward CDC34A. We further demonstrate how PPI-CONA can be applied to screening very low affinity interactions. PPI-CONA holds potential for high-throughput screening for modulators of PPI targets and characterization of their affinity, specificity, and selectivity.

Molecular Design Motifs of Non‐Fullerene Acceptors for Mitigating All Inherent Non‐Ideal Energy Losses in Organic Photovoltaics

AbstractNon‐fullerene acceptors (NFAs) have demonstrated a great potential for the transcendence of performance limits in organic photovoltaics. Despite the tremendous efforts, however, synthetic control of non‐ideal recombination losses on the photovoltage are still elusive and thus lag far behind the inorganic counterparts. Here, a rational design strategy of non‐fullerene acceptors is presented to overcome the limitations derived from the inherent excited state properties of organic molecules. Spectroscopic studies on a series of chemical analogs of ladder‐type fused acceptors reveal that the radiative efficiency of non‐fullerene acceptors is predominantly determined by the inherently strong electron‐vibration coupling of their bound excited states, rather than the redistribution of molecular orbitals itself. In this sense, regardless of intramolecular charge transfer characteristics, the incorporation of rigid, and planar moiety with wide π plane is found to promote the dominance of long‐lived and weakly‐bound excited states in the photophysical process, in which the mitigated non‐radiative decays of NFAs can be directly translated into that of charge‐transfer states. Furthermore, the incorporation of such chemical moiety can minimize the evolution of subgap broadening in the bulk heterojunction blends, lowering the contribution of non‐ideal radiative losses. As a result, the model systems demonstrate the non‐radiative loss down to 180–190 meV, without sacrificing photocurrent generations, reaching that of inorganic counterparts.

Discovery of a 6-Aminobenzo[b]thiophene 1,1-Dioxide Derivative (K2071) with a Signal Transducer and Activator of Transcription 3 Inhibitory, Antimitotic, and Senotherapeutic Activities.

6-Nitrobenzo[b]thiophene 1,1-dioxide (Stattic) is a potent signal transducer and activator of the transcription 3 (STAT3) inhibitor developed originally for anticancer therapy. However, Stattic harbors several STAT3 inhibition-independent biological effects. To improve the properties of Stattic, we prepared a series of analogues derived from 6-aminobenzo[b]thiophene 1,1-dioxide, a compound directly obtained from the reduction of Stattic, that includes a methoxybenzylamino derivative (K2071) with optimized physicochemical characteristics, including the ability to cross the blood-brain barrier. Besides inhibiting the interleukin-6-stimulated activity of STAT3 mediated by tyrosine 705 phosphorylation, K2071 also showed cytotoxicity against a set of human glioblastoma-derived cell lines. In contrast to the core compound, a part of K2071 cytotoxicity reflected a STAT3 inhibition-independent block of mitotic progression in the prophase, affecting mitotic spindle formation, indicating that K2071 also acts as a mitotic poison. Compared to Stattic, K2071 was significantly less thiol-reactive. In addition, K2071 affected cell migration, suppressed cell proliferation in tumor spheroids, exerted cytotoxicity for glioblastoma temozolomide-induced senescent cells, and inhibited the secretion of the proinflammatory cytokine monocyte chemoattractant protein 1 (MCP-1) in senescent cells. Importantly, K2071 was well tolerated in mice, lacking manifestations of acute toxicity. The structure-activity relationship analysis of the K2071 molecule revealed the necessity of the para-substituted methoxyphenyl motif for antimitotic but not overall cytotoxic activity of its derivatives. Altogether, these results indicate that compound K2071 is a novel Stattic-derived STAT3 inhibitor and a mitotic poison with anticancer and senotherapeutic properties that is effective on glioblastoma cells and may be further developed as an agent for glioblastoma therapy.

Gem-Difluoroalkylation of Cyclic Ethers Enabled by Cobalt-Catalyzed C(sp3)-H Oxidation under Mild Conditions.

Fluorinated rings have emerged as privileged structural modules in the fields of drug discovery and materials research. The incorporation of fluorine atoms into aromatic rings or heterocycles can lead to significant improvements in the physicochemical and biological properties of small molecules, making them valuable components in the design of new drugs and functional materials. Herein, we presented a cobalt-catalyzed C-H oxidation/gem-difluorination cascade reaction of readily available cyclic ethers with difluoroenoxysilanes, affording a series of gem-difluorinated analogues with moderate to high yields. The obtained products as versatile fluoroalkyl building blocks were showcased through divergent-oriented transformations.

Novel Piperazine Derivatives as Potent Antihistamine, Anti-Inflammatory, and Anticancer Agents, their Synthesis and Characterization.

In this study, a series of novel piperazine derivatives were synthesised with high-to-good yields, and their structural analogies were confirmed using FTIR, 1H-NMR, and LC-MS techniques. The synthesised compounds were evaluated for antioxidant and antimicrobial activities. Among the four synthesised piperazine derivatives, compound PD-2 exhibited relatively good antioxidant activity, with an IC50 value of 2.396 μg/mL, while the other three derivatives showed moderate to low antioxidant activity. Furthermore, compound PD-2 displayed antimicrobial activity against Pseudomonas aeruginosa, a gram-negative bacterium, and Candida albicans, a fungus. However, all four compounds showed strong resistance against grampositive bacteria, Staphylococcus aureus. Additionally, compound PD-1 exhibited significant antihistamine activity, eliciting an 18.22% reduction in histamine levels. Both PD-1 and PD-2 demonstrated noteworthy anti-inflammatory activity in a dosedependent manner (5-10 μM), leading to the inhibition of nitrite production up to 39.42% and 33.7% at higher concentrations (10 μM) and inhibition of tumour necrosis factor-alpha (TNF-α) generation up to 56.97% and 44.73% at 10 μM, respectively. Additionally, both novel molecules PD-1 and PD-2 effectively restrained the growth of HepG2 cells in a manner that is dependent on the dosage up to 55.44% and 90.45% at the highest concentrations (100 μg/mL), respectively. These findings substantiate the rationale for further investigation into the novel series of persuasive piperazine analogues as potential agents with anti-inflammatory, antihistamine and anticancer properties.

Design, synthesis and biological evaluation of glucose metabolism inhibitors as anticancer agents

Compared to normal cells, tumour cells exhibit an upregulation of glucose transporters and an increased rate of glycolytic activity. In previous research, we successfully identified a promising hit compound BH10 through a rigorous screening process, which demonstrates a potent capacity for inhibiting cancer cell proliferation by targeting glucose metabolism. In the current study, we identify Kelch-like ECH-associated protein 1 (Keap1) as a potential protein target of BH10via avidin pull-down assays with biotinylated-BH10. Subsequently, we present a comprehensive analysis of a series of BH10 analogues characterized by the incorporation of a naphthoimidazole scaffold and the introduction of a triazole ring with diverse terminal functional groups. Notably, compound 4d has emerged as the most potent candidate, exhibiting better anti-cancer activities against HEC1A cancer cells with an IC50 of 2.60 μM, an extended biological half-life, and an improved pharmacokinetic profile (compared to BH10) in mice.

A click-chemistry based strategy for synthesizing coumarin piperazine analogues: Assessment of anti-tubercular, anti-cancer, anti-inflammatory and antioxidant potentials

In this study, a novel series of coumarin piperazine analogues were synthesized using Click chemistry approach. Thus synthesized compounds (8a-j) were evaluated for their pharmacological potentialities. These compounds subjected for evaluation of their anti-tubercular, anti-cancer, anti-inflammatory, and antioxidant properties. Results revealed that analogues 8b, 8d, 8i and 8h are found to be the promising drug-like candidates against Mycobacterium tuberculosis H37Rv strain exhibiting more potent activity than isoniazid with MIC of 2.24, 1.04, 3.72, 5.35 µM respectively. Furthermore, the compound 8d displayed better anti-inflammatory and antioxidant activity with IC50 values of 66.43 µM and 69.14 µM respectively. Molecular docking studies insights into the binding affinities and interactions with a target protein. The in silico ADME profiles supported their pharmacokinetic viability. Predominantly, compound 8d exhibited anticancer activity with IC50 values of 12.42 µM and 26.16 µM with reference to HeLa and MCF-7respectively by inhibiting acetyl-CoA synthetase. These findings highlight more specifically the compound 8d as a potent anti-cancer agent.

Investigation of the site 2 pocket of Grp94 with KUNG65 benzamide derivatives

Glucose-regulated protein 94 (Grp94) is an isoform of the heat shock protein 90 kDa (Hsp90) family of molecular chaperones. Inhibiting Grp94 has been implicated for many diseases. Co-crystal structures of two generations of Grp94 inhibitors revealed the importance of investigating the ester group, which is projected into the site 2 pocket unique to Grp94. Therefore, a series of KUNG65 benzamide analogs was designed and synthesized to evaluate their impact on the affinity and selectivity for Grp94. The data demonstrated that substituents with small and saturated ring systems that contain hydrogen bond acceptors exhibited increased affinity for Grp94, whereas larger saturated ring system manifested increased selectivity for Grp94 over Hsp90α.

Effects of Selective and Mixed-Action Kappa and Delta Opioid Receptor Agonists on Pain-Related Behavioral Depression in Mice.

We recently developed a series of nalfurafine analogs (TK10, TK33, and TK35) that may serve as non-addictive candidate analgesics. These compounds are mixed-action agonists at the kappa and delta opioid receptors (KOR and DOR, respectively) and produce antinociception in a mouse warm-water tail-immersion test while failing to produce typical mu opioid receptor (MOR)-mediated side effects. The warm-water tail-immersion test is an assay of pain-stimulated behavior vulnerable to false-positive analgesic-like effects by drugs that produce motor impairment. Accordingly, this study evaluated TK10, TK33, and TK35 in a recently validated assay of pain-related behavioral depression in mice that are less vulnerable to false-positive effects. For comparison, we also evaluated the effects of the MOR agonist/analgesic hydrocodone (positive control), the neurokinin 1 receptor (NK1R) antagonist aprepitant (negative control), nalfurafine as a selective KOR agonist, SNC80 as a selective DOR agonist, and a nalfurafine/SNC80 mixture. Intraperitoneal injection of dilute lactic acid (IP lactic acid) served as a noxious stimulus to depress vertical and horizontal locomotor activity in male and female ICR mice. IP lactic acid-induced locomotor depression was alleviated by hydrocodone but not by aprepitant, nalfurafine, SNC80, the nalfurafine/SNC80 mixture, or the KOR/DOR agonists. These results suggest that caution is warranted in advancing mixed-action KOR/DOR agonists as candidate analgesics.

Benzothiazole‐Piperazine Hybrids Effectively Target C4‐2 Castration‐Resistant Prostate Cancer Cells in vitro Implicated through Computational Studies

AbstractA series of new analogs based on benzothiazole‐piperazine conjugates were synthesized and assessed to investigate their anticancer properties using in vitro and in silico techniques. The compounds 3 a–3 h were tested against prostate (C4‐2) cancer cells, and the results revealed that all the compounds showed significant inhibitory activity against C4‐2 cells (>50 % inhibition at 20 μM). Among all, 2‐(4‐(pyrimidin‐2‐yl) piperazin‐1‐yl) benzo[d]thiazole demonstrated the most prominent activity in the cell viability assay conducted displaying an IC50 value of 19.98 μM. In vitro studies have demonstrated that the compound can selectively target the androgen receptor (AR) and reduce the expression of several androgen‐responsive genes, including EAF2, ELL2, PSA and CALR genes, in castration‐resistant prostate cancer cells. Molecular docking results also revealed that all the compounds exhibited good energy binding scores against the androgen receptor target (PB ID: 2PNU) particularly compound 3 g which showed a maximum binding energy of −9.87 kcal/mol followed by other compounds as well as the established prostate cancer drug, enzalutamide, with a binding energy of −5.66 kcal/mol. Docking results were further supported by MD simulation studies, which confirmed that the ligand+protein complex was in stable conformation throughout the simulation time of 100 nanoseconds. Collectively, the present results, stemming from a combination of in vitro and in silico examinations, demonstrate that compound 3 g displays notable anti‐cancer characteristics, implying its viability as a prospective anti‐cancer pharmaceutical subject to clinical validation and subsequent development.

Revisiting the dipeptidyl carboxypeptidase inhibitor captopril as a source of pan anti-trypanosomatid agents

The protozoan parasites Trypanosoma brucei, Trypanosoma cruzi and Leishmania spp. are responsible for continued propagation of neglected tropical diseases such as African sleeping sickness, Chagas disease and leishmaniasis respectively. Following a report that captopril targets Leishmania donovani dipeptidyl carboxypeptidase, a series of simple proline amides and captopril analogues were synthesized and found to exhibit 1–2 μM in vitro inhibition and selectivity against Trypanosoma brucei, Trypanosoma cruzi and Leishmania spp. The results were corroborated with computational docking studies. Arguably, the synthetic proline amides represent the structurally simplest examples of in vitro pan antiprotozoal compounds.

A classic antibiotic reimagined: Rationally designed bacitracin variants exhibit potent activity against vancomycin-resistant pathogens

Bacitracin is a macrocyclic peptide antibiotic that is widely used as a topical treatment for infections caused by gram-positive bacteria. Mechanistically, bacitracin targets bacteria by specifically binding to the phospholipid undecaprenyl pyrophosphate (C55PP), which plays a key role in the bacterial lipid II cycle. Recent crystallographic studies have shown that when bound to C55PP, bacitracin adopts a highly ordered amphipathic conformation. In doing so, all hydrophobic side chains align on one face of the bacitracin-C55PP complex, presumably interacting with the bacterial cell membrane. These insights led us to undertake structure-activity investigations into the individual contribution of the nonpolar amino acids found in bacitracin. To achieve this we designed, synthesized, and evaluated a series of bacitracin analogues, a number of which were found to exhibit significantly enhanced antibacterial activity against clinically relevant, drug-resistant pathogens. As for the natural product, these next-generation bacitracins were found to form stable complexes with C55PP. The structure-activity insights thus obtained serve to inform the design of C55PP-targeting antibiotics, a key and underexploited antibacterial strategy.