Structure-activity Relationship Research Articles

Unveiling the therapeutic potential of azopyridine derivatives for trypsin inhibition: a DFT and In-Vitro approach

Heterocyclic azo derivatives have emerged as promising scaffolds for drug development. This study focused on the synthesis, computational analysis, and biological evaluation of a series of azopyridine derivatives (1a, 1d, 1 g, 1 h, 1 m, 1p, and 1s) as potential trypsin inhibitors. Density Functional Theory calculations indicated that derivative 1 h exhibited the lowest HOMO-LUMO energy gap 3.167 eV and was characterised as a soft molecule, suggesting strong binding capabilities. Molecular docking studies confirmed that 1 h binds favourably to the active site of trypsin with a glide score of −6.581 kcal/mol and binding energy of −29.95 kcal/mol. Along with docking studies, the stability of the trypsin-1 h complex was further analyzed using molecular dynamic simulations at 200 ns. The results showed that the ligand molecule 1 h bound strongly at the active site of trypsin. In-vitro enzyme assays determined the IC50 value of the molecule as 100 µM, demonstrating enhanced potency. These results indicate that AzPy derivatives, particularly 1 h, hold considerable promise as therapeutic agents for inflammatory disorders and cancer, paving the way for further exploration in drug development and targeted therapies. Further research is warranted to explore 1h’s efficacy, safety, and structure-activity relationships. Highlights: DFT studies were used to classify molecules based on their softness and hardness. Molecular docking, simulation, and in-vitro studies have identified potential anti-trypsin activity of candidate molecules. Experimental and computational calculations were in close agreement.

Scoliidines: Neuroprotective Peptides in Solitary Scoliid Wasp Venoms.

A comprehensive LC-MS study examined the venom components of the solitary scoliid wasp Scolia oculata. Online mass fingerprinting showed that crude venom contains 25 small molecules (amino acids, biogenic amines, and nucleosides/nucleotides) and 45 peptides with MW 400-2700. The small molecules were identified by elemental composition analysis, and peptide sequences were determined by ESI-MS/MS and MALDI-TOF/TOF MS analyses. As major peptide components, a known peptide, β-scoliidine (DYVTVKGFSPLRKA), and three new peptides, γ-scoliidine (YVTVKGFSPLR), δ-scoliidine (YVTVKGFSPLREP) and ε-scoliidine (DYVTVKGFSPLREP) were identified, all of which are closely homologous to each other. Once the neuroprotective effects of β-scoliidine have already been described, the other three new scoliidine peptides were analyzed against oxidative stress-induced toxicity in PC12 neuronal cells by mitochondrial metabolism assay, and the structure-activity relationship was evaluated. Interestingly, pre-treatment with ε-scoliidine increased the mitochondrial metabolism of PC12 cells (106 ± 3.6%; p = 0.007) exposed to H2O2-induced oxidative stress in contrast to γ- and δ-scoliidines (77.6 ± 4.8 and 68.5 ± 4.1%, respectively) in compared to cells treated only H2O2 (75.8 ± 2.4%). These new peptides were also analyzed for enzyme inhibitor/substrate assays with angiotensin-converting enzyme (ACE), neprilysin (NEP), and acetylcholinesterase (AChE). In these assays, only δ- and ε-scoliidines increased the AChE activity (128.7 ± 3.8%; p = 0.01; and 116.8 ± 3.8% p = 0.03; respectively) in relation to basal activity (100.1 ± 1.6%). In addition, the four peptides were analyzed through in silico analysis, and none of them demonstrated possible hemolytic and toxic activities. In our study, the comprehensive LC-MS and MS/MS analyses of Scolia oculate venom identified four major peptide components of the venom β-, γ-, δ- and ε-scoliidines, and small differences in their primary structures are important to their neuroprotective properties.

Development of a selective COX-2 inhibitor: from synthesis to enhanced efficacy via nano-formulation.

Non-steroidal anti-inflammatory drugs NSAIDs are widely used for managing various conditions including pain, inflammation, arthritis and many musculoskeletal disorders. NSAIDs exert their biological effects by inhibiting the cyclooxygenase (COX) enzyme, which has two main isoforms COX-1 and COX-2. The COX-2 isoform is believed to be directly related to inflammation. Based on structure-activity relationship (SAR) studies of known selective COX-2 inhibitors, our aim is to design and synthesize a novel series of 2-benzamido-N-(4-substituted phenyl)thiophene-3-carboxamide derivatives. These derivatives are intended to be selective COX-2 inhibitors through structural modification of diclofenac and celecoxib. The compound 2-benzamido-5-ethyl-N-(4-fluorophenyl)thiophene-3-carboxamide VIIa demonstrated selective COX-2 inhibition with an IC50 value of 0.29 μM and a selectivity index 67.24. This is compared to celecoxib, which has an IC50 value of 0.42 μM and a selectivity index 33.8. Molecular docking studies for compound VIIa displayed high binding affinity toward COX-2. Additionally, the suppression of protein denaturation with respect to albumin was performed as an indicative measure of the potential anti-inflammatory efficacy of the novel compounds. Compound VIIa showed potent anti-inflammatory activity with 93% inhibition and an IC50 value 0.54 μM. In comparison, celecoxib achieved 94% inhibition with an IC50 value 0.89 μM. Although molecule VIIa demonstrated significant in vitro anti-inflammatory activity, adhered to Lipinski's "five rules" (RO5) and exhibited promising drug-like properties, it showed indications of poor in vivo activity. This limitation is likely due to poor aqueous solubility, which impacts its bioavailability. This issue could be addressed by incorporating the drug in niosomal nanocarrier. Niosomes were prepared using the thin-film hydration technique. These niosomes exhibited a particle size of less than 200 nm, high entrapment efficiency, and an appropriate drug loading percentage. Transmission electron microscopy (TEM) and differential scanning calorimetry (DSC) studies revealed that the niosomes were spherical and demonstrated compatibility of all of its components. The drug release study indicated that the pure drug had limited practicality for in vivo use. However, incorporating the drug into niosomes significantly improved its release profile, making it more suitable for practical use.

Structure-Activity Relationship of Substituted Pyrazoline Derivatives as Small Molecule Tyrosine Kinase Inhibitors.

Tyrosine kinase inhibitors (TKIs) target certain cell signalling pathways, and have become a promising class of medications for the treatment of cancer in recent years. Because of their distinct structure and adaptable chemistry, pyrazolines have drawn a lot of interest from organic and medicinal chemists. Their exceptional TKI activity has prompted them to investigate chemotherapy for cancer. We aim to develop agents that inhibit tyrosine kinases highly effective with the least amount of harm possible, perhaps improving the course of cancer treatment. This review compiled current information from recent literature sources, includ-ing in vitro, in vivo, approved medications, active clinical trials, and the structure-activity relationships (SAR) linked to various pyrazoline analogues used as small-molecule Tyro-sine Kinase Inhibitors in cancer treatment. This study focuses on SAR inside the pyrazoline ring and its derivatives as TKIs, and it emphasizes current developments, including patents, authorized medications, and compounds in clinical trials. By enhancing our understanding of these compounds, our goal is to aid in making the roles of pharmacologists, scientists, and researchers who are designing and developing next-generation anticancer drugs with pyrazoline scaffolds easier. The future holds immense potential for the continued evolution of pyrazoline-based therapies, offer-ing renewed hope in the ongoing battle against cancer.

Mechanistic Studies of Small Molecule Ligands Selective to RNA Single G Bulges.

Small-molecule RNA binders have emerged as an important pharmacological modality. A profound understanding of the ligand selectivity, binding mode, and influential factors governing ligand engagement with RNA targets is the foundation for rational ligand design. Here, we report a novel class of coumarin derivatives exhibiting selective binding affinity towards single G RNA bulges. Harnessing the computational power of all-atom Gaussian accelerated Molecular Dynamics (GaMD) simulations, we unveiled a rare minor groove binding mode of the ligand with a key interaction between the coumarin moiety and the G bulge. This predicted binding mode is consistent with results obtained from structure-activity-relationship (SAR) studies and transverse relaxation measurements by NMR spectroscopy. We further generated 444 molecular descriptors from 69 coumarin derivatives and identified key contributors to the binding events, such as charge state and planarity, by lasso (least absolute shrinkage and selection operator) regression. Strikingly, small structure perturbations on these key contributors, such as the addition of a methyl group that disrupts the planarity of the ligand resulted in > 100-fold reduction in the binding affinity. Our work deepened the understanding of RNA-small molecule interactions and integrated a new generalizable platform for the rational design of selective small-molecule RNA binders.

Design, Synthesis, and 3D-QASR of Oxazoline Derivatives Containing an S-S Moiety as Potential Acaricide.

To mitigate the detrimental effects of agricultural pest mites on crop yield, an active substructure splicing strategy was employed to modify etoxazole by introducing an S-S moiety. The target products were obtained efficiently via a bilateral disulfurating reagent (DSMO), which was developed by our group. The leaf dip method was used to evaluate the activities of the designed target compounds against the eggs and larvae of the spider mite (Tetranychus cinnabarinus). Most of the target compounds exhibited good efficacy in controlling the larvae and eggs of T. cinnabarinus. Based on these results, a three-dimensional quantitative structure-activity relationship (3D-QSAR) model was established to guide the construction of compound 7l. Notably, compound 7l exhibited a better activity against T. cinnabarinus eggs (LC50 = 0.0035 mg/L) compared to etoxazole (LC50 = 0.2990 mg/L). Greenhouse bioassays indicated that compound 7l exhibits excellent acaricidal activity against egg of T. cinnabarinus, which is better than the etoxazole at 1.0 mg/L. Additionally, some of the compounds showed inhibitory effects against Dickeya zeae (D. zeae), Xanthomonas campestris pv campestris (Xcc), Xanthomonas oryzae pvoryza (Xoo), and Xanthomonas oryzae pvoryzicola (Xoc). Furthermore, compounds 7l not only exhibited relatively potent against Plutella xylostella activities (LC50 = 24.0 mg/L) but also had low toxicity (LC50 > 11.0 μg/bee) to Apis mellifera. In conclusion, the current experimental results suggest that oxazoline derivatives containing an S-S moiety have the potential to serve as lead compounds for the development of novel acaricide agents.

Atomic-level design of biomimetic iron-sulfur clusters for biocatalysis.

Designing biomimetic materials with high activity and customized biological functions by mimicking the central structure of biomolecules has become an important avenue for the development of medical materials. As an essential electron carrier, the iron-sulfur (Fe-S) clusters have the advantages of simple structure and high electron transport capacity. To rationally design and accurately construct functional materials, it is crucial to clarify the electronic structure and conformational relationships of Fe-S clusters. However, due to the complex catalytic mechanism and synthetic process in vitro, it is hard to reveal the structure-activity relationship of Fe-S clusters accurately. This review introduces the main structural types of Fe-S clusters and their catalytic mechanisms first. Then, several typical structural design strategies of biomimetic Fe-S clusters are systematically introduced. Furthermore, the development of Fe-S clusters in the biocatalytic field is enumerated, including tumor treatment, antibacterial, virus inhibition and plant photoprotection. Finally, the problems and development directions of Fe-S clusters are summarized. This review aims to guide people to accurately understand and regulate the electronic structure of Fe-S at the atomic level, which is of great significance for designing biomimetic materials with specific functions and expanding their applications in biocatalysis.

Rational Design and Stereodivergent Construction of Enantioenriched Tetrahydro-β-Carbolines Containing Multistereogenic Centers.

Chiral tetrahydro-β-carbolines, as one of the most intriguing subtypes of indole alkaloids, have emerged as the privileged units in plenty of natural products and biologically active molecules with an impressive range of bioactive properties. However, the stereodivergent construction of these valuable skeletons containing multistereogenic centers from readily available starting materials remains very challenging, especially, in view of the introduction of an axial chirality. Herein, we developed an efficient method toward enantioenriched tetrahydro-β-carbolines with readily available tryptophan-derived aldimine esters and allylic carbonates under mild reaction conditions. The reaction proceeds in a sequential fashion involving synergistic Cu/Ir-catalyzed stereodivergent allylation and the Brønsted acid-promoted stereospecific Pictet-Spengler reaction, affording a wide range of chiral tetrahydro-β-carbolines bearing up to four stereogenic centers in good yields with excellent stereoselectivity control. When N-aryl-substituted tryptophan-derived aldimine esters were utilized, notably, a unique C-N heterobiaryl axis could be simultaneously constructed with the formation of the third point stereogenic center in the last cyclization step through dynamic kinetic resolution (DKR). Computational mechanistic studies established a plausible synergistic mechanism for dual Cu/Ir-catalyzed asymmetric allylation and the succeeding protonation-assisted Pictet-Spengler cyclization to complete the annulation. Structure-activity relationship analyses unveil the origins of stereochemistry for the building of one axis and three point stereogenic centers.

Design, In Silico, and In vitro Evaluation of Polymer-Based Drug Conjugates Incorporated with Derivative of Cinnamic Acid, Zidovudine, and 4-Aminosalicylic Acid against Pseudo-HIV-1.

The incorporation of anti-HIV drugs into polymer to form polymer-drug conjugates has been reported to result in improved therapeutic activity. Zidovudine, an anti-HIV drug, was explored alone and in combination with known drug molecules using polyamidoaminebased carriers. Polymer-drug conjugates incorporated with zidovudine, cinnamic acid, and 4-aminosalicylic acid were prepared and evaluated for their potential efficacy in vitro against pseudo- HIV-1. Aqueous Michael addition polymerization reaction was employed to prepare the conjugates. The conjugates were incorporated with zidovudine, cinnamic acid, and 4-aminosalicylic acid. They were characterized by SEM/EDX, XRD, FTIR, NMR, LC-MS, particle size analysis, in vitro analysis, computational studies, and in silico toxicity predictions. The conjugates displayed spherically shaped morphology. The in vitro findings showed that polymer-drug conjugates, T15 and T16, with a single drug were effective against pseudo- HIV-1 at high concentrations of 111.11 and 333.33 μg/mL, respectively. The molecular docking studies confirmed the in vitro results. The Swiss ADME, ProTox-II, and GUSAR (General Unrestricted Structure-Activity Relationships) revealed that these compounds are promising antiviral compounds. The prepared polymer-drug conjugates with a single drug showed promising effects against the Pseudo-HIV-1, and the conjugates displayed features that make them potential anti- HIV therapeutics that require further studies.

Computational Strategies for Assessing Adverse Outcome Pathways: Hepatic Steatosis as a Case Study.

The evolving landscape of chemical risk assessment is increasingly focused on developing tiered, mechanistically driven approaches that avoid the use of animal experiments. In this context, adverse outcome pathways have gained importance for evaluating various types of chemical-induced toxicity. Using hepatic steatosis as a case study, this review explores the use of diverse computational techniques, such as structure-activity relationship models, quantitative structure-activity relationship models, read-across methods, omics data analysis, and structure-based approaches to fill data gaps within adverse outcome pathway networks. Emphasizing the regulatory acceptance of each technique, we examine how these methodologies can be integrated to provide a comprehensive understanding of chemical toxicity. This review highlights the transformative impact of in silico techniques in toxicology, proposing guidelines for their application in evidence gathering for developing and filling data gaps in adverse outcome pathway networks. These guidelines can be applied to other cases, advancing the field of toxicological risk assessment.

An Insight into Medicinal Chemistry and SAR Studies of Cholinesterase and BACE-1 Inhibitors for Alzheimer's Disease.

Alzheimer's Disease (AD) is a serious neurodegenerative condition that predominantly impacts the cholinergic neurons of the entorhinal cortex and hippocampal regions, playing a critical role in learning, navigation, and brain processing. This paper aims to discuss the three main hypotheses of Alzheimer's disease, focusing on neurotoxicity and neurodegeneration caused by mitochondrial dysfunction and ROS production, particularly analyzing the susceptibility differences between genders. Our comprehensive review focuses on significant findings from the past five years, particularly on Cholinesterase (ChE) and BACE-1 inhibitors. Researchers have conducted a detailed analysis of in vitro, in silico, and in vivo data, incorporating extensive Structure-Activity Relationship (SAR) studies. The reviewed papers have been sourced from platforms, such as Google Scholar, Semantic Scholar, and ClinicalTrials.gov, and have been selected based on their AChE and BACE-1 inhibitory activity and structural motif similarity. The review identifies the most effective compounds targeting ChE and BACE-1, highlighting acridine, dihydropyridine, and thiazole-coumarin hybrids for ChE inhibition, and oxadiazole, benzofuran, and dihydropyrimidinone for BACE-1 inhibition. This demonstrates a diverse array of potent heterocyclic hybrids. The review presents a varied compilation of scaffolds showing promise in treating Alzheimer's disease, highlighting the potential of specific compounds against ChE and BACE-1. Given the critical insights derived from our analysis, we posit that this compilation will substantially contribute to the ongoing efforts to combat neurodegeneration and prolong dementia, underscoring the importance of continuous research in this domain.

Synthesis, computational analysis, and anti-proliferative evaluation of novel bithienylbenzamidine derivatives: Towards cytostatic cancer therapeutics

Our research unveils the synthesis and characterization of four novel monocationic 2,5-diarylbithiophene derivatives 4a-d, prepared through Suzuki cross-coupling reactions and subsequent amidine formation. Density Functional Theory (DFT) calculations provide unprecedented insights into the electronic properties and structure-activity relationships of these compounds. In vitro screening against the NCI-60 cancer cell panel demonstrates remarkable anti-proliferative activities. Compound 4c emerges as a standout candidate, exhibiting potent growth inhibition across multiple cancer types, with GI50 values as low as 0.36 µM against certain ovarian cancer lines. Intriguingly, our research suggests a potential shift from purely cytotoxic towards more cytostatic behavior, potentially offering improved therapeutic windows and reduced side effects. Molecular docking studies provide evidence for the compounds' interaction with human carbonic anhydrase IX, hinting at a possible mechanism of action. This comprehensive study not only introduces a promising new class of anti-cancer compounds but also provides a rich foundation of structural, electronic, and biological data to fuel future research. The bithienylbenzamidine derivatives, particularly compound 4c, represent exciting candidates for further development in the ongoing battle against cancer.

Machine Learning-Enhanced Screening of Single-Atom Alloy Clusters for Nitrogen Reduction Reaction.

The electrochemical nitrogen reduction reaction (eNRR) under ambient conditions is a promising method to generate ammonia (NH3), a crucial precursor for fertilizers and chemicals, without carbon emissions. Single-atom alloy catalysts (SAACs) have reinvigorated catalytic processes due to their high activity, selectivity, and efficient use of active atoms. Here, we employed density functional theory (DFT) calculations integrated with machine learning (ML) to investigate dodecahedral nanocluster-based SAACs for analyzing structure-activity relationships in eNRR. Over 300 nanocluster-based SAACs were screened with all the transition metals as dopants to develop an ML model predicting stability and catalytic performance. Facet sites were identified as optimal doping positions, particularly with late group transition metals showing superior stability and activity. Utilizing DFT+ML, we identified 8 highly suitable SAACs for eNRR. Interestingly, the number of valence d-electrons in dopants proved crucial in screening for eNRR activity. These catalysts exhibited low activity in hydrogen evolution reaction, further enhancing their suitability for eNRR. This successful ML-driven approach accelerates catalyst design and discovery, holding significant practical implications.

Rapid Systematic Screening of Bispecific Antibody Surrogate Geometries for T-Cell Engagement Using DNA Nanotechnology.

Bispecific antibodies (bsAbs) are emerging immune-therapeutics, and many formats exist that differ considerably in structure. However, little systematic data exist about how the spatial organization of their components influences activity, requiring innovative approaches combining empirical and quantitative frameworks. This study presents a modular DNA nanotechnology platform to generate numerous bsAbs with surrogate geometries that span the structural features of the BiTE, IgG-like, and IgG-conjugate platforms to screen for T-cell engagement. Results highlight interesting structure-activity relationships regarding bsAb potency and selectivity and raise questions regarding the molecular phenomena underlying activity. To elucidate some effects, the platform was paired with a simple mathematical model. This work is thus one of the first to systematically investigate and reveal the importance of the spatial organization of bsAb components on activity and equally provides an accessible and convenient tool for rapidly mapping out such trends for other combinations of target epitopes.

Thermal proteome profiling reveals fructose-1,6-bisphosphate as a phosphate donor to activate phosphoglycerate mutase 1

Deep understanding of sugar metabolite-protein interactions should provide implications on sugar metabolic reprogramming in human physiopathology. Although tremendous efforts have been made for determining individual event, global profiling of such interactome remains challenging. Here we describe thermal proteome profiling of glycolytic metabolite fructose-1,6-bisphosphate (FBP)-interacting proteins. Our results reveal a chemical signaling role of FBP which acts as a phosphate donor to activate phosphoglycerate mutase 1 (PGAM1) and contribute an intrapathway feedback for glycolysis and cell proliferation. At molecular level, FBP donates either C1-O-phosphate or C6-O-phosphate to the catalytic histidine of PGAM1 to form 3-phosphate histidine (3-pHis) modification. Importantly, structure-activity relationship studies facilitate the discovery of PGAM1 orthostatic inhibitors which can potentially restrain cancer cell proliferation. Collectively we have profiled a spectrum of FBP interactome, and discovered a unique covalent signaling function of FBP that supports Warburg effect via histidine phosphorylation which inspires the development of pharmacological tools targeting sugar metabolism.

Classics in Chemical Neuroscience: Medetomidine.

Medetomidine is an FDA-approved α2-adrenoreceptor (α2-AR) agonist used as a veterinary sedative due to its analgesic, sedative, and anxiolytic properties. While it is marketed for veterinary use as a racemic mixture under the brand name Domitor, the pharmacologically active enantiomer, dexmedetomidine, is approved for sedation and analgesia in the hospital setting. Medetomidine has recently been detected in the illicit drug supply alongside fentanyl, xylazine, cocaine, and heroin, producing pronounced sedative effects that are not reversed by naloxone. The pharmacological effects along with the low cost of supply and lack of regulation for medetomidine has made it a target for misuse. Since 2022, medetomidine has been found as an adulterant in samples of seized drugs, as well as in toxicological analyses of patients admitted to the emergency department after suspected overdoses across several U.S. states and Canada. This Review will discuss the history, chemistry, structure-activity relationships, drug metabolism and pharmacokinetics (DMPK), pharmacology, and emergence of medetomidine as an adulterant in drug mixtures in the context of the current opioid drug crisis.

Synthesis, C-N/N-N bond conformational analysis and evaluation of naphtho[2,3-d][1,2,3]triazole-4,9-dione tethered N-acyl hydrazones as α-amylase inhibitors: Insights from molecular modeling and ADMET analysis

In an effort to expand the repertoire of potent α-amylase inhibitors, we sought to develop novel inhibitors by combining 1,4-naphthoquinone, 1,2,3-triazole, and N-acyl hydrazone scaffolds in a single matrix. To achieve this, twelve novel naphtho[2,3-d][1,2,3]triazole-4,9‑dione tethered N-acyl hydrazones were synthesized through condensation reaction of 2-(4,9-dioxo-4,9-dihydro-1H-naphtho[2,3-d][1,2,3]triazol-1-yl)acetohydrazide with various substituted aryl aldehydes. Structural elucidation for all the compounds was performed using 1D, 2D-NMR, FTIR, and mass spectral analyses. The synthesized molecules were evaluated for their ability to inhibit α-amylase activity using acarbose as the standard drug. All the derivatives exhibited potent inhibition of α-amylase, with IC50 values ranging between 17.26 ± 0.07 to 25.62 ± 0.03 μg/mL. Notably, compound 9c possessing –meta substituted –NO2 group displayed the highest activity (IC50 = 17.26 ± 0.07 μg/mL) among the series. Structure-activity relationship (SAR) revealed the pivotal role of aryl ring substitutions in determining inhibitory efficacy. To validate these findings and to assess the binding stability of 9c within the catalytic site α-amylase dervied for A. oryzae (PDB ID:7TAA), in silico studies were performed. The compound 9c effectively occupies the enzyme's active pocket, with minimal RMSD fluctuations observed over 100 ns simulation, indicating stable protein-ligand complex. ADMET predictions suggested favorable drug-like properties, underscoring the potential of these compounds as novel α-amylase inhibitors for managing type 2 diabetes mellitus

Assessment of high-efficacy agonism in synthetic cannabinoid receptor agonists containing l-tert-leucinate.

Synthetic cannabinoid receptor agonists (SCRAs) represent a class of new psychoactive substances that pose great health risks attributed to their wide-ranging and severe adverse effects. Recent evidence has shown that SCRAs with key moieties can confer superagonism, yet this phenomenon is still not well understood. In this study, we developed a structure-activity relationship (SAR) for SCRA superagonism by comparing eight compounds differing by their head moiety (l-valinate vs. l-tert-leucinate), core moiety (indole vs. indazole), and tail moiety (5-fluoropentyl vs. 4-fluorobenzyl) through different modes of bioluminescence resonance energy transfer (BRET). We found that l-tert-leucinate head moiety and indazole core moiety conferred superagonism across multiple Gαi/o proteins and β-arrestin 2. Finally, after generating CB1R mutant constructs, we found that transmembrane 2 (TM2) interactions to the head moiety of tested SCRAs at F170, F177, and H178 are key to eliciting activity.

Pyrazolo-Pyrimidinones with Improved Solubility and Selective Inhibition of Adenylyl Cyclase Type 1 Activity for Treatment of Inflammatory Pain.

Adenylyl cyclase isoform 1 (AC1) is considered a promising target for treating inflammatory pain. Our group identified the pyrazolyl-pyrimidinone scaffold as potent and selective inhibitors of Ca2+/CaM-mediated AC1 activity; however, the molecules suffered from poor aqueous solubility. The current study presents a strategy to improve aqueous solubility of the scaffold by reduction of crystal packing energy and increasing rotational degrees of freedom within the molecule. Structure-activity and property relationship studies identified the second generation lead 7-47A (AC10142A) that demonstrated and AC1 IC50 value of 0.26 μM and aqueous solubility of 74 ± 7 μM. After in vitro ADME characterization, the scaffold advanced to in vivo pharmacokinetic evaluation, demonstrating adequate levels of exposure. Finally, 7-47A exhibited antiallodynic efficacy in a rat complete Freund's adjuvant model for inflammatory pain showing improvement over previous iterations of this scaffold. These results further validate AC1 inhibition as a viable therapeutic strategy for treating chronic and inflammatory pain.

Potent Anti-Influenza Synergistic Activity of Theobromine and Arainosine.

Influenza represents one of the biggest health threats facing humanity. Seasonal epidemics can transition to global pandemics, with cross-species infection presenting a continuous challenge. Although vaccines and several anti-viral options are available, constant genetic drifts and shifts vitiate any of the aforementioned prevention and treatment options. Therefore, we describe an approach targeted at the virus's channel to derive new anti-viral options. Specifically, Influenza A's M2 protein is a well-characterized channel targeted for a long time by aminoadamantane blockers. However, widespread mutations in the protein render the drugs ineffective. Consequently, we started by screening a repurposed drug library against aminoadamantane-sensitive and resistant M2 channels using bacteria-based genetic assays. Subsequent in cellulo testing and structure-activity relationship studies yielded a combination of Theobromine and Arainosine, which exhibits stark anti-viral activity by inhibiting the virus's channel. The drug duo was potent against H1N1 pandemic swine flu, H5N1 pandemic avian flu, aminoadamantane-resistant and sensitive strains alike, exhibiting activity that surpassed Oseltamivir, the leading anti-flu drug on the market. When this drug duo was tested in an animal model, it once more outperformed Oseltamivir, considerably reducing disease symptoms and viral RNA progeny. In conclusion, the outcome of this study represents a new potential treatment option for influenza alongside an approach that is sufficiently general and readily applicable to other viral targets.