C3 amino-substituted chalcone derivative with selective adenosine rA1 receptor affinity in the micromolar range

Exploring ethynyl-based chalcones as green semiconductor materials for optical limiting interests

The fabrication of molecular electronics from non-toxic functional materials which eventually would potentially able to degrade or being breaking down into safe by-products have attracted much interests in recent years. Hence, in this study, the introduction of mixed highly functional substructures of chalcone (-CO-CH=CH-) and ethynylated (C≡C) as building blocks has shown ideal performance as solution-processed thin film candidatures. Two types of derivatives, (MM-3a) and (MM-3b) repectively, showed a substantial Stokes shifts at 75 nm and 116 nm, in which such emission exhibits an intramolecular charge transfer (ICT) state and fluoresce characteristics. The density functional theory (DFT) simulation shows that MM-3a and MM-3b exhibit low energy gaps of 3.70 eV and 2.81 eV, respectively. TD-DFT computations for molecular electrostatic potential (MEP) and frontier molecular orbitals (FMO) were also used to emphasise the structure-property relationship. A solution-processed thin film with a single layer of ITO/PEDOT:PSS/MM-3a-MM-3b/Au exhibited electroluminescence behaviour with orange and purple emissions when supplied with direct current (DC) voltages. To promote the safer application of the derivatives formed, ethynylated chalcone materials underwent toxicity studies toward Acanthamoeba sp. to determine their suitability as non-toxic molecules prior to the determination as safer materials in optical limiting interests. From the preliminary test, no IC50 value was obtained for both compounds via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay analysis and molecular docking analysis between MM-3a and MM-3b, with profilin protein exhibited weak bond interactions and attaining huge interaction distances.

Curcumin Chalcone Derivatives Database (CCDD): a Python framework for natural compound derivatives database

We built the Curcumin Chalcone Derivatives Database (CCDD) to enable the effective virtual screening of highly potent curcumin and its analogs. The two-dimensional (2D) structures were drawn using the ChemBioOffice package and converted to 3D structures using Discovery Studio Visualizer V 2021 (DS). The database was built using different Python modules. For the 3D structures, different Python packages were used to obtain the data frame of compounds. This framework is also used to visualize the compounds. The webserver enables the users to screen the compounds according to Lipinski's rule of five. The structures can be downloaded in .sdf and .mol format. The data frame (df) can be downloaded in .csv format. Our webserver can help computational drug discovery researchers find new therapeutics and build new webservers. The CCDD is freely available at: https://srampogu-ccdd-ccdd-8uldk8.streamlit.app/.

Natural-Derived COX-2 Inhibitors as Anticancer Drugs: A Review of their Structural Diversity and Mechanism of Action

Cyclooxygenase-2 (COX-2) is a key-type enzyme playing a crucial role in cancer development, making it a target of high interest for drug designers. In the last two decades, numerous selective COX-2 inhibitors have been approved for various clinical conditions. However, data from clinical trials propose that the prolonged use of COX-2 inhibitors is associated with life-threatening cardiovascular side effects. The data indicate that a slight structural modification can help develop COX-2 selective inhibitors with comparative efficacy and limited side effects. In this regard, secondary metabolites from natural sources offer great hope for developing novel COX-2 inhibitors with potential anticancer activity. In recent years, various nature-derived organic scaffolds are being explored as leads for developing new COX-2 inhibitors. The current review attempts to highlight the COX-2 inhibition activity of some naturally occurring secondary metabolites, concerning their capacity to inhibit COX-1 and COX-2 enzymes and inhibit cancer development, aiming to establish a structure-activity relationship.

Chalcones as Potential Ligands for the Treatment of Parkinson's Disease

Along with the increase in life expectancy, a significant increase of people suffering from neurodegenerative diseases (ND) has been noticed. The second most common ND, after Alzheimer’s disease, is Parkinson’s disease (PD), which manifests itself with a number of motor and non-motor symptoms that hinder the patient’s life. Current therapies can only alleviate those symptoms and slow down the progression of the disease, but not effectively cure it. So now, in addition to understanding the mechanism and causes of PD, it is also important to find a powerful way of treatment. It has been proved that in the etiology and course of PD, the essential roles are played by dopamine (DA) (an important neurotransmitter), enzymes regulating its level (e.g., COMT, MAO), and oxidative stress leading to neuroinflammation. Chalcones, due to their “simple” structure and valuable biological properties are considered as promising candidates for treatment of ND, also including PD. Here, we provide a comprehensive review of chalcones and related structures as potential new therapeutics for cure and prevention of PD. For this purpose, three databases (Pubmed, Scopus and Web of Science) were searched to collect articles published during the last 5 years (January 2018–February 2022). Chalcones have been described as promising enzyme inhibitors (MAO B, COMT, AChE), α-synuclein imaging probes, showing anti-neuroinflammatory activity (inhibition of iNOS or activation of Nrf2 signaling), as well as antagonists of adenosine A₁ and/or A_2A receptors. This review focused on the structure–activity relationships of these compounds to determine how a particular substituent or its position in the chalcone ring(s) (ring A and/or B) affects biological activity.

Design, synthesis and evaluation of amino-3,5-dicyanopyridines and thieno[2,3-b]pyridines as ligands of adenosine A1 receptors for the potential treatment of epilepsy

Due to the implication of adenosine in seizure suppression, adenosine-based therapies such as adenosine receptor (AR) agonists have been investigated. This study aimed at investigating thieno[2,3-b]pyridine derivatives as non-nucleoside A₁ agonists that could be used in pharmaco-resistant epilepsy (PRE). Compound 7c (thieno[2,3-b]pyridine derivative), displayed good binding affinity to the rA₁ AR (K_i = 61.9 nM). This could be a breakthrough for further investigation of this heterocyclic scaffold as potential ligand. In silico evaluation of this compound raised bioavailability concerns but performed well on drug-likeness tests. The effect of intramolecular cyclisation that occurs during synthesis of thieno[2,3-b]pyridines from the lead compounds, amino-3,5-dicyanopyridine derivatives (6a-s) in relation to AR binding was also evaluated. A significant loss of activity against rA₁/rA_2A ARs with cyclisation was revealed. Amino-3,5-dicyanopyridines exhibited greater affinity towards rA₁ ARs (K_i < 10 nM) than rA_2A. Compound 6c had the best rA₁ affinity (K_i = 0.076 nM). Novel compounds (6d, 6k, 6l, 6m, 6n, 6o, 6p) were highly selective towards rA₁ AR (K_i between 0.179 and 21.0 nM). Based on their high selectivity for A₁ ARs, amino-3,5-dicyanopyridines may be investigated further as AR ligands in PRE with the right structural optimisations and formulations.

Chalcone-inspired rA1 /A2A adenosine receptor ligands: Ring closure as an alternative to a reactive substructure

Over the past few years, great progress has been made in the development of high-affinity adenosine A₁ and/or A_2A receptor antagonists-promising agents for the potential treatment of Parkinson's disease. Unfortunately, many of these compounds raise structure-related concerns. The present study investigated the effect of ring closures on the rA₁ /A_2A affinity of compounds containing a highly reactive α,β-unsaturated carbonyl system, hence providing insight into the potential of heterocycles to address these concerns. A total of 12 heterocyclic compounds were synthesised and evaluated in silico and in vitro. The test compounds performed well upon qualitative assessment of drug-likeness and were generally found to be free from potentially problematic fragments. Most also showed low/weak cytotoxicity. Results from radioligand binding experiments confirm that heterocycles (particularly 2-substituted 3-cyanopyridines) can replace the promiscuous α,β-unsaturated ketone functional group without compromising A₁ /A_2A affinity. Structure-activity relationships highlighted the importance of hydrogen bonds in binding to the receptors of interest. Compounds 3c (rA₁ K_i  = 16 nM; rA_2A K_i  = 65 nM) and 8a (rA₁ K_i  = 102 nM; rA_2A K_i  = 37 nM), which both act as A₁ antagonists, showed significant dual A₁ /A_2A affinity and may, therefore, inspire further investigation into heterocycles as potentially safe and potent adenosine receptor antagonists.