Development of bromo- and fluoro-based α, β-unsaturated ketones as highly potent MAO-B inhibitors for the treatment of Parkinson's disease

Novel 2-aminothiazole derivatives incorporating 9-alkyl purine moiety: design, synthesis, crystal structure, and bioactivity evaluation

A series of 2-aminothiazole derivatives (3A1-3A30) containing 9-alkyl purine moiety were designed and synthesized to explore novel antibacterial agents with unique structures and potent antibacterial activity. The structures of target compounds were characterized using 1H NMR, 13C NMR, and HRMS techniques. The structure of compound 3A12 was further elucidated through single crystal X-ray diffraction analysis. Results from antibacterial activity tests indicated that compound 3A7 exhibited a significant inhibitory effect on Xanthomonas oryzae pv. oryzicola (Xoc), with an EC50 (half-maximal effective concentration) value of 25.5 μg/mL, which was more than three times higher than that of the control agent thiodiazole copper (EC50 = 78.4 μg/mL). Compound 3A25 has a strong inhibitory effect on Xanthomonas axonopodis pv. citric (Xac), with significantly higher activity than thiodiazole copper in terms of EC50 value (47.3 vs 92.1 µg/mL). Additionally, the EC50 value of compound 3A7 against Pseudomonas syringae pv. actinidiae (Psa) was measured at 57.5 µg/mL, demonstrating superior efficacy relative to the control agents bismerthiazol (EC50 = 92.9 µg/mL) and thiodiazole copper (EC50 = 90.2 µg/mL). The antibacterial mechanism of compound 3A7 was examined through an investigation into the production of exopolysaccharides, alterations in membrane permeability, morphological changes in bacterial cells, and the development of a molecular docking model. Through a 100 ns molecular dynamics (MD) simulation, the stability of the binding between compound 3A7 and the AvrRxo1-ORF1 protein was confirmed. Furthermore, the chemical reactivity of potential bioactive compounds was evaluated using density functional theory (DFT).

The Effects of Lamium garganicum L. Subsp. lasioclades (Stapf.) R. Mill Plant Against Fibroblast (U2OS Cell), Acetylcholinesterase, Glutathione S-Transferase: An In Vitro, In Silico Biological Activity Screening Study

In this study, some biological activities of extracts of Lamium garganicum subsp. lasioclades (Lgl) have been evaluated as well as identified the phenolic composition. Concentration ranges of 31.25, 62.5, 125, 250, and 500 µg/mL were applied to determine the extract's anticancer properties. Significant results were obtained against the osteosarcoma cell line (U2OS cell) compared to normal human umbilical vein endothelial cells (HUVEC). To determine the antioxidant activities, ABTS, DPPH, FRAP, and CUPRAC methods were studied in vitro. Enzyme inhibition effects of methanol extract against the glutathione S-transferase (GST) and acetylcholinesterase (AChE) enzymes were investigated. IC50 values were calculated as 12.96 µL/mL for AChE and 13.02 µg/mL for GST, respectively. The phenolic contents of the plant extract were analyzed by HPLC. The interaction mechanisms of protein-ligand complexes formed by AChE and GST receptors with gallic acid and rutin were investigated by molecular docking studies. The stability of the complexes formed between receptors and ligands was confirmed by root mean square deviation (RMSD), root mean square fluctuation (RMSF), number of average hydrogen bonding interactions (Hb), and radius of gyration (Rg) analyses obtained from 100 ns molecular dynamics simulations.

Therapeutic Role of Heterocyclic Compounds in Neurodegenerative Diseases: Insights from Alzheimer's and Parkinson's Diseases

Alzheimer's and Parkinson's are the most common neurodegenerative diseases (NDDs). The development of aberrant protein aggregates and the progressive and permanent loss of neurons are the major characteristic features of these disorders. Although the precise mechanisms causing Alzheimer's disease (AD) and Parkinson's disease (PD) are still unknown, there is a wealth of evidence suggesting that misfolded proteins, accumulation of misfolded proteins, dysfunction of neuroreceptors and mitochondria, dysregulation of enzymes, and the release of neurotransmitters significantly influence the pathophysiology of these diseases. There is no effective protective medicine or therapy available even with the availability of numerous medications. There is an urgent need to create new and powerful bioactive compounds since the number of people with NDDs is rising globally. Heterocyclic compounds have consistently played a pivotal role in drug discovery due to their exceptional pharmaceutical properties. Many clinically approved drugs, such as galantamine hydrobromide, donepezil hydrochloride, memantine hydrochloride, and opicapone, feature heterocyclic cores. As these heterocyclic compounds have exceptional therapeutic potential, heterocycles are an intriguing research topic for the development of new effective therapeutic drugs for PD and AD. This review aims to provide current insights into the development and potential use of heterocyclic compounds targeting diverse therapeutic targets to manage and potentially treat patients with AD and PD.

Optimizing Linezolid: Transforming It into a Selective MAO-B Inhibitor via a Toxicity-to-Activity Optimization Approach

Linezolid, a widely used oxazolidinone antibiotic, exhibits potent activity against resistant bacterial infections but is associated with serotonergic toxicity, primarily due to its inhibition of monoamine oxidase (MAO). MAOs, consisting of MAO-A and MAO-B isoforms, play crucial roles in neurotransmitter metabolism, with implications for neurodegenerative disorders like Parkinson's and Alzheimer's diseases. This study aims to optimize Linezolid's structure to transform it into a selective MAO-B inhibitor. Utilizing structure-activity and structure-toxicity relationship approaches, novel analogues of Linezolid were synthesized by replacing its oxazolidinone ring with a thiadiazole scaffold. Among the synthesized compounds, 6b emerged as a lead candidate, displaying a remarkable MAO-B inhibitory activity (IC50 = 0.03 μM) and 464-fold selectivity over MAO-A, compared to the standard drugs Pargyline (IC50 = 0.14 μM) and Clorgyline (IC50 = 1.85 μM). Furthermore, docking and molecular dynamics simulations corroborated the high affinity and stability of compound 6b in the MAO-B enzyme's binding pocket. These findings suggest that optimized Linezolid analogues, particularly compound 6b, hold promise as selective MAO-B inhibitors, offering therapeutic potential for treating neurodegenerative diseases while avoiding the risks associated with serotonergic toxicity.

A Review on Therapeutic Strategies against Parkinson's Disease: Current Trends and Future Perspectives

Parkinson's Disease (PD) is the most common neurodegenerative disorder after Alzheimer's Disease and is clinically expressed by movement disorders, such as tremor, bradykinesia, and rigidity. It occurs mainly in the extrapyramidal system of the brain and is characterized by dopaminergic neuron degeneration. L-DOPA, dopaminergic agonists, anticholinergic drugs, and MAO-B inhibitors are currently used as therapeutic agents against PD, however, they have only symptomatic efficacy, mainly due to the complex pathophysiology of the disease. This review summarizes the main aspects of PD pathology, as well as, discusses the most important biochemical dysfunctions during PD, and presents novel multi-targeting compounds, which have been tested for their activity against various targets related to PD. This review selects various research articles from main databases concerning multi-targeting compounds against PD. Molecules targeting more than one biochemical pathway involved in PD, expected to be more effective than the current treatment options, are discussed. A great number of research groups have designed novel compounds following the multi-targeting drug approach. They include structures combining antioxidant, antiinflammatory, and metal-chelating properties. These compounds could be proven useful for effective multi-targeted PD treatment. Multi-targeting drugs could be a useful tool for the design of effective antiparkinson agents. Their efficacy towards various targets implicated in PD could be the key to the radical treatment of this neurodegenerative disorder.

Inhibition of monoamine oxidases by heterocyclic derived conjugated dienones: synthesis and in vitro and in silico investigations

A total of 18 heterocyclic derived conjugated dienones (CD1-CD18) were evaluated for their potential monoamine oxidase (MAO)-A/-B inhibitory activity. Among the analyzed molecules, CD11 and CD14 showed notable inhibitory potentials against MAO-B, with half-maximal inhibitory concentration (IC50) values of 0.063 ± 0.001 μM and 0.036 ± 0.008 μM, respectively. In contrast, CD1, CD2 and CD3 showed comparable inhibitory activities toward MAO-A, with IC50 values of 3.45 ± 0.07, 3.23 ± 0.24, and 3.15 ± 0.10 μM, respectively. Derivatives of thiophene (CD13-CD17) exhibited selectivity indices greater than 250 for MAO-B. Both lead compounds exhibited similar potencies to safinamide and were more potent than pargyline. According to kinetic analysis, CD11 and CD14 exhibited competitive inhibition of MAO-B activity, with K i values of 12.67 ± 3.85 nM and 4.5 ± 0.62 nM, respectively. Furthermore, the reversibility test results indicated that the inhibitions were reversible. Molecular docking and molecular dynamics simulation studies can provide insights into the probable binding interactions of CD11 and CD14 with MAO-B. CD11 demonstrated a bipartite contact with Tyr326 and Phe343, whereas CD14 showed contact with Pro102 and Tyr435 via aromatic hydrogen bonds. These results indicated that both compounds have high-affinity binding interactions ( -10.13 and -9.90 kcal mol-1, respectively) at the active site of MAO-B. Furthermore, we used SwissADME to estimate ADME, and both lead compounds demonstrated blood-brain barrier penetration. The study results indicated that all the compounds evaluated demonstrated potent inhibition of MAO-B activity, which was comparable to the efficacy of reference medications. It is necessary to do further investigations on the lead molecules to see whether they may be used to treat different neurodegenerative illnesses.

Significance of Chalcone Scaffolds in Medicinal Chemistry

Chalcone is a simple naturally occurring α,β-unsaturated ketone with biological importance, which can also be easily synthesized in laboratories by reaction between two aromatic scaffolds. In plants, chalcones occur as polyphenolic compounds of different frameworks which are bioactive molecules that have been in traditional medicinal practice for many years. Chalcone-based lead molecules have been developed, possessing varied potentials such as antimicrobial, antiviral, anti-inflammatory, anticancer, anti-oxidant, antidiabetic, antihyperurecemic, and anti-ulcer effects. Chalcones contribute considerable fragments to give important heterocyclic molecules with therapeutic utilities targeting various diseases. These characteristic features have made chalcone a topic of interest among researchers and have attracted investigations into this widely applicable structure. This review highlights the extensive exploration carried out on the synthesis, biotransformations, chemical reactions, hybridization, and pharmacological potentials of chalcones, and aims to provide an extensive, thorough, and critical review of their importance, with emphasis on their properties, chemistry, and biomedical applications to boost future investigations into this potential scaffold in medicinal chemistry.

Synthesis, biological evaluation and molecular modeling studies of modulated benzyloxychalcones as potential acetylcholinesterase inhibitors

Acetylcholinesterase inhibitors (AChEIs) have become a significant target in the search for an efficient treatment of Alzheimer's disease. Chalcone-based compounds display a strong potency to hinder AChE. So, this study focused on the synthesis of a series of new chalcone derivatives with anti-cholinesterase potential and their structures were characterized based on spectroscopic methods including IR, 1H NMR, 13C NMR and HRMS. Chalcone derivatives were screened against AChE. Most of them exhibited potent inhibitory activity against AChE. Compound 11i showed the most potent activity toward acetylcholinesterase compared to the positive compound, Galantamine. Docking studies into the active site of the acetylcholinesterase enzyme ravealed the significant docking score of the synthesized compounds with docking score of -7.959 to -9.277 kcal/mol when compared to the co-crystallized ligand, Donepezil (-10.567 kcal/mol). The interaction's stability was further assessed using a conventional atomistic 100 ns dynamics simulation study, which revealed the conformational stability of representative compound 11i in the cavity of the acetylcholinesterase enzyme.Communicated by Ramaswamy H. Sarma.

Design and synthesis of some novel hybrid molecules based on 4-thiazolidinone bearing pyridine-pyrazole scaffolds: molecular docking and molecular dynamics simulations of its major constituent onto DNA gyrase inhibition

Due to multidrug resistance, microbial infections have become significant on a global level. As infections caused by several resistant bacteria and fungi severely harm mankind, scientists have developed new antibiotics to combat these infections. In order to develop novel antimicrobial agents, a series of 4-thiazolidinone-based 5-arylidene hybrids (5a-o) have been designed and synthesized to evaluate their antibacterial and antifungal activities. For the determination of the structure of a novel synthesized hybrid, various spectral techniques, e.g., IR, 1H NMR, 13C NMR, and Mass spectroscopy, were used. Two bacterial gram-negative (Escherichia coli and Pseudomonas aeruginosa), two gram-positive strains (Staphylococcus aureus and Streptococcus pyogenes), and one fungal strain (Candida albicans) were used to evaluate antimicrobial activity. Compounds 5c, 5g, and 5i were effective due to their MIC values of 62.5 μg/mL against tested bacterial strains (S. pyogenes (5c), P. aeruginosa (5g), and E. coli (5i), respectively.) and 250 μg/mL against C. albicans fungal strains, respectively. Additionally, molecular docking and 100 ns molecular dynamic simulations were carried out to investigate the stability of molecular contacts and to establish how the newly synthesized inhibitors fit together in the most stable conformations.

Machine learning driven web-based app platform for the discovery of monoamine oxidase B inhibitors

Monoamine oxidases (MAOs), specifically MAO-A and MAO-B, play important roles in the breakdown of monoamine neurotransmitters. Therefore, MAO inhibitors are crucial for treating various neurodegenerative disorders, including Parkinson's disease (PD), Alzheimer's disease (AD), and amyotrophic lateral sclerosis (ALS). In this study, we developed a novel cheminformatics pipeline by generating three diverse molecular feature-based machine learning-assisted quantitative structural activity relationship (ML-QSAR) models concerning MAO-B inhibition. PubChem fingerprints, substructure fingerprints, and one-dimensional (1D) and two-dimensional (2D) molecular descriptors were implemented to unravel the structural insights responsible for decoding the origin of MAO-B inhibition in 249 non-reductant molecules. Based on a random forest ML algorithm, the final PubChem fingerprint, substructure fingerprint, and 1D and 2D molecular descriptor prediction models demonstrated significant robustness, with correlation coefficients of 0.9863, 0.9796, and 0.9852, respectively. The significant features of each predictive model responsible for MAO-B inhibition were extracted using a comprehensive variance importance plot (VIP) and correlation matrix analysis. The final predictive models were further developed as a web application, MAO-B-pred ( https://mao-b-pred.streamlit.app/ ), to allow users to predict the bioactivity of molecules against MAO-B. Molecular docking and dynamics studies were conducted to gain insight into the atomic-level molecular interactions between the ligand-receptor complexes. These findings were compared with the structural features obtained from the ML-QSAR models, which supported the mechanistic understanding of the binding phenomena. The presented models have the potential to serve as tools for identifying crucial molecular characteristics for the rational design of MAO-B target inhibitors, which may be used to develop effective drugs for neurodegenerative disorders.

GC-MS screening of the phytochemical composition of Ziziphus honey: ADME properties and in vitro/in silico study of its antimicrobial activity

A revival interest has been given to natural products as sources of phytocompounds to be used as alternative treatment against infectious diseases. In this context, we aimed to investigate the antimicrobial potential of Ziziphus honey (ZH) against twelve clinical bacterial strains and several yeasts and molds using in vitro and computational approaches. The well-diffusion assay revealed that ZH was able to induce growth inhibition of most Gram-positive and Gram-negative bacteria. The high mean growth inhibition zone (mGIZ) was recorded in E. coli (Clinical strain, 217), S. aureus followed by E. coli ATCC 10536 (mGIZ values: 41.00 ± 1 mm, 40.67 ± 0.57 mm, and 34.67 ± 0.57 mm, respectively). The minimal bactericidal concentrations (MBCs) and minimal fungicidal concentration values (MFCs) from approximately 266.33 mg/mL to over 532.65 mg/mL. Molecular docking results revealed that the identified compounds maltose, 2-furoic acid, isopropyl ester, 2,4-imidazolidinedione, 5-(2-methylpropyl)-(S)- and 3,4,5-trihydroxytoluene, S-Methyl-L-Cysteine, 2-Furancarboxylic acid, L-Valine-N-ethoxycarbonyl, Hexanoic acid, 3,5,5-trimethyl-, Methyl-beta-D-thiogalactoside, gamma-Sitosterol, d-Mannose, 4-O-Methylmannose, 2,4-Imidazolidinedione, 5-(2-methylpropyl)- (S) were found to have good affinity for targeted receptor, respectively. Through a 100-ns dynamic simulation research, binding interactions and stability between promising phytochemicals and the active residues of the studied enzymes were confirmed. The ADMET profiling of all identified compounds revealed that most of them could be qualified as biologically active with good absorption and permeation. Overall, the results highlighted the efficiency of ZH against the tested clinical pathogenic strains. The antimicrobial potential and the potency displayed by the identified compounds could imply their further pharmacological applications.Communicated by Ramaswamy H. Sarma.

Two dimensional-QSAR and molecular dynamics studies of a selected class of aldoxime- and hydroxy-functionalized chalcones as monoamine oxidase-B inhibitors

Candidates generated from unsaturated ketone (chalcone) demonstrated as strong, reversible and specific monoamine oxidase-B (MAO-B) inhibitory activity. For the research on MAO-B inhibition, our team has synthesized and evaluated a panel of aldoxime-chalcone ethers (ACE) and hydroxylchalcones (HC). The MAO-B inhibitory activity of several candidates is in the micro- to nanomolar range in these series. The purpose of this research was to develop predictive QSAR models and look into the relation between MAO-B inhibition by aldoxime and hydroxyl-functionalized chalcones. It was shown that the molecular descriptors ETA Shape P, MDEO-12, ETA dBetaP, SpMax1 Bhi and ETA EtaP B are significant in the inhibitory action of the MAO-B target. Using the current 2D QSAR models, potential chalcone-based MAO-B inhibitors might be created. The lead molecules were further analyzed by the detailed molecular dynamics study to establish the stability of the ligand-enzyme complex.Communicated by Ramaswamy H. Sarma.

In Vitro and In Silico Evaluation of Antiproliferative Activity of New Isoxazolidine Derivatives Targeting EGFR: Design, Synthesis, Cell Cycle Analysis, and Apoptotic Inducers

A series of novel enantiopure isoxazolidine derivatives were synthesized and evaluated for their anticancer activities against three human cancer cell lines such as human breast carcinoma (MCF-7), human lung adenocarcinoma (A-549), and human ovarian carcinoma (SKOV3) by employing MTT assay. The synthesized compounds were characterized by NMR and elemental analysis. Results revealed that all the synthesized compounds displayed significant inhibition towards the tested cell lines. Among them, 2g and 2f, which differ only by the presence of an ester group at the C-3 position and small EDG (methyl) at the C-5 position of the phenyl ring (2g), were the most active derivatives in attenuating the growth of the three cells in a dose-dependent manner. The IC₅₀ for 2g were 17.7 ± 1 µM (MCF-7), 12.1 ± 1.1 µM (A-549), and 13.9 ± 0.7 µM (SKOV3), and for 2f were 9.7 ± 1.3µM (MCF-7), 9.7 ± 0.7µM (A-549), and 6.5 ± 0.9µM (SKOV3), respectively, which were comparable to the standard drug, doxorubicin. The enzymatic inhibition of 2f and 2g against EGFR afforded good inhibitory activity with IC₅₀ of 0.298 ± 0.007 μM and 0.484 ± 0.01 µM, respectively, close to the positive control, Afatinib. Compound 2f arrested the cell cycle in the S phase in MCF-7 and SKOV3 cells, and in the G2/M phase in the A549 cell; however, 2g induced G0/G1 phase cell cycle arrest, and inhibited the progression of the three cancer cells, together with significant apoptotic effects. The docking study of compounds 2f and 2g into EGFR ATP-active site revealed that it fits nicely with good binding affinity. The pharmacokinetic and drug-likeness scores revealed notable lead-like properties. At 100 ns, the dynamic simulation investigation revealed high conformational stability in the EGFR binding cavity.

Halogenated class of oximes as a new class of monoamine oxidase-B inhibitors for the treatment of Parkinson's disease: Synthesis, biochemistry, and molecular dynamics study

Oximes are the promising structural scaffold for inhibiting monoamine oxidase (MAO)-B. Eight chalcone-based oxime derivatives were synthesized by microwave-assisted technique, and their ability to inhibit human MAO (hMAO) enzymes were tested. All compounds showed higher inhibitory activity of hMAO-B than hMAO-A. In the CHBO subseries, CHBO4 most potently inhibited hMAO-B with an IC₅₀ value of 0.031 μM, followed by CHBO3 (IC₅₀ = 0.075 μM). In the CHFO subseries, CHFO4 showed the highest inhibition of hMAO-B with an IC₅₀ value of 0.147 μM. Compound CHBO4 had the highest selectivity index (SI) value of 1290.3. However, CHBO3 and CHFO4 showed relatively low SI values of 27.7 and 19.2, respectively. The -Br substituent in the CHBO subseries at the para-position in the B-ring showed higher hMAO-B inhibition than the -F substituent in the CHFO subseries. In both series, hMAO-B inhibition increased with the substituents at para-position in A-ring (-F > -Br > -Cl > -H in order). Compound CHBO4 (-F in A-ring and -Br in B-ring) was 12.6-times potent than the substituents-reversed compound CHFO3 (-Br in A-ring and -F in B-ring; IC₅₀ = 0.391 μM). In the kinetic study, K_i values of CHBO4 and CHFO4 for hMAO-B were 0.010 ± 0.005 and 0.040 ± 0.007 μM, respectively, with competitive inhibitions. Reversibility experiments showed that CHBO4 and CHFO4 were reversible hMAO-B inhibitors. In the cytotoxicity test using the Vero cells by the MTT technique, CHBO4 had low toxicity with an IC₅₀ value of 128.8 µg/mL. In H₂O₂-induced cells, CHBO4 significantly reduced cell damage by scavenging reactive oxygen species (ROS). Molecular docking and dynamics showed the stable binding mode of the lead molecule CHBO4 on the active site of hMAO-B. These results suggest that CHBO4 is a potent reversible, competitive, and selective hMAO-B inhibitor and can be used as a treatment agent for neurological disorders.

Structure-based drug design, molecular dynamics simulation, ADMET, and quantum chemical studies of some thiazolinones targeting influenza neuraminidase

The genetic mutability of the influenza virus leads to the existence of drug-resistant strains which is dangerous, particularly with the lingering coronavirus disease (COVID-19). This necessitated the need for the search and discovery of more potential anti-influenza agents to avert future outbreaks. In furtherance of our previous in-silico studies on 5-benzyl-4-thiazolinones as anti-influenza neuraminidase (NA) inhibitors, molecule 11 was selected as the template scaffold for the structure-based drug design due to its good binding, pharmacokinetic profiling, and better NA inhibitory activity. As such, eighteen (18) new molecules (11a-r) were designed with better MolDock scores as compared with the template scaffold and the zanamivir reference drug. However, the dynamic stability of molecule 11a in the binding cavity of the NA target (3TI5) showed water-mediated hydrogen and hydrophobic bondings with the active residues such as Arg118, Ile149, Arg152, Ile222, Trp403, and Ile427 after the MD simulation for 100 ns. The drug-likeness and ADMET assessment of all designed molecules predicted non-violation of the stipulated thresholds of Lipinski's rule and good pharmacokinetic properties respectively. In addition, the quantum chemical calculations also suggested the significant chemical reactivity of molecules with their smaller band energy gap, high electrophilicity, high softness, and low hardness. The results obtained in this study proposed a reliable in-silico viewpoint for anti-influenza drug discovery and development.Communicated by Ramaswamy H. Sarma.

Isoflavonoid and Furanochromone Natural Products as Potential DNA Gyrase Inhibitors: Computational, Spectral, and Antimycobacterial Studies

In pursuit of new antitubercular agents, we here report the antimycobacterial (H₃₇Rv) and DNA gyrase inhibitory potential of daidzein and khellin natural products (NPs). We procured a total of 16 NPs based on their pharmacophoric similarities with known antimycobacterial compounds. The H₃₇Rv strain of M. tuberculosis was found to be susceptible to only two out of the 16 NPs procured; specifically, daidzein and khellin each exhibited an MIC of 25 μg/mL. Moreover, daidzein and khellin inhibited the DNA gyrase enzyme with IC₅₀ values of 0.042 and 0.822 μg/mL, respectively, compared to ciprofloxacin with an IC₅₀ value of 0.018 μg/mL. Daidzein and khellin were found to have lower toxicity toward the vero cell line, with IC₅₀ values of 160.81 and 300.23 μg/mL, respectively. Further, molecular docking study and MD simulation of daidzein indicated that it remained stable inside the cavity of DNA GyrB domain for 100 ns.

Phytochemical Investigation, In Silico/In Vivo Analgesic, and Anti-inflammatory Assessment of the Egyptian Cassia occidentalis L

Cassia occidentalis L., from Fabaceae family phytochemical screening, revealed several biologically active principles mainly flavonoids and anthraquinones. GLC analysis of the lipoidal matter afforded 12 hydrocarbons: 9-dodecyl-tetradecahydro-anthracene (48.97 %), 9-dodecyl-tetradecahydro-phenanthrene (14.43 %), and 6 sterols/triterpenes: iso-jaspisterol (11.99%) and fatty acids were palmitic acid (50 %), and Linoleic acid (16.06%). Column chromatography led to the isolation of fifteen compounds (1-15), elucidated using spectroscopic evidence. First report of undecanoic acid (4) from the family Fabaceae, while p-dimethyl amino-benzaldehyde (15) was first time isolated from a natural origin. Eight compounds isolated for the first time from C. occidentalis L.; β-amyrin (1), β-sitosterol (2), stigmasterol (3), camphor (5), lupeol (6), chrysin (7), pectolinargenin (8), and 1, 2, 5-trihydroxy anthraquinone (14) besides five known compounds previously isolated; apigenin (9), kaempferol (10), chrysophanol (11), physcion (12), and aloe-emodin (13). In-vivo evaluation of anti-inflammatory and analgesic effects of C. occidentalis L. extracts where the n-butanol and total extracts showed the highest activities. The percentage of the inhibitory effect of the n-butanol extract was 29.7 at a dose of 400 mg/Kg. Furthermore, identified phytoconstituents were docked into the active sites of enzymes nAChRs, COX-1, and COX-2 to evaluate binding affinity. Phyto-compounds Physcion, aloe-emodin, and chrysophanol were found to have a good affinity for targeted receptors compared to co-crystalized inhibitors, validating the analgesic and anti-inflammatory effects of the phytochemicals.

Synthesis, characterization, molecular dynamic simulation, and biological assessment of cinnamates linked to imidazole/benzimidazole as a CYP51 inhibitor

A class of 2-(1H-imidazol-1-yl)-1-phenylethyl cinnamates 6a-6j and 2-(1H-benzo[d]imidazol-1-yl)-1-phenylethyl cinnamates 7a-7j were synthesized, and their synthesis was validated using various spectroscopic techniques like IR, NMR, and Mass spectrometry. In addition, the compounds were assessed for in-vitro antibacterial against gram-positive and gram-negative strains and in-vitro antifungal against six different fungal strains. Compounds 6 g, 7 b, 7f, and 7 g exhibited significant activity against all bacterial strains ranging from MIC = 12.5-50 µg/mL, and compounds 6 g, 7 b, and 7 g exhibited considerable activity against all fungal strains ranging from MFC = 125-200 µg/mL. A molecular docking study indicated that compounds 6 g, 7 b, 7 g, and 7j could be lodged in the active pocket and inhibit C. albicans Sterol 14α-demethylase (CYP51) protein via various interactions, and these studies validate the antifungal results. Different parameters from the 100 ns MD simulation study are investigated to evaluate the dynamic stability of protein-ligand complexes. According to the MD simulation study, the proposed compounds effectively kept their molecular interaction and structural integrity within the C. albicans Sterol 14-demethylase. Compounds 6 g, 7 b, and 7 g are promising lead compounds in searching for novel antifungal drug-like molecules. Furthermore, in silico ADME indicates that these compounds possess drug-like physicochemical properties to be orally bioavailable.Communicated by Ramaswamy H. Sarma.

Introduction of benzyloxy pharmacophore into aryl/heteroaryl chalcone motifs as a new class of monoamine oxidase B inhibitors

The inhibitory action of fifteen benzyloxy ortho/para-substituted chalcones (B1-B15) was evaluated against human monoamine oxidases (hMAOs). All the molecules inhibited hMAO-B isoform more potently than hMAO-A. Furthermore, the majority of the molecules showed strong inhibitory actions against hMAO-B at 10 μM level with residual activities of less than 50%. Compound B10 has an IC₅₀ value of 0.067 μM, making it the most potent inhibitor of hMAO-B, trailed by compound B15 (IC₅₀ = 0.12 μM). The thiophene substituent (B10) in the A-ring exhibited the strongest hMAO-B inhibition structurally, however, increased residue synthesis did not result in a rise in hMAO-B inhibition. In contrast, the benzyl group at the para position of the B-ring displayed more hMAO-B inhibition than the other positions. Compounds B10 and B15 had relatively high selectivity index (SI) values for hMAO-B (504.791 and 287.600, respectively). K_i values of B10 and B15 were 0.030 ± 0.001 and 0.033 ± 0.001 μM, respectively. The reversibility study showed that B10 and B15 were reversible inhibitors of hMAO-B. PAMPA assay manifested that the benzyloxy chalcones (B10 and B15) had a significant permeability and CNS bioavailability with Pe value higher than 4.0 × 10^-6 cm/s. Both compounds were stabilized in protein-ligand complexes by the π-π stacking, which enabled them to bind to the hMAO-B enzyme's active site incredibly effectively. The hMAO-B was stabilized by B10- and B15-hMAO-B complexes, with binding energies of - 74.57 and - 87.72 kcal/mol, respectively. Using a genetic algorithm and multiple linear regression, the QSAR model was created. Based on the best 2D and 3D descriptor-based QSAR model, the following statistics were displayed: R² = 0.9125, Q²_loo = 0.8347. These findings imply that B10 and B15 are effective, selective, and reversible hMAO-B inhibitors.

Thymus musilii Velen. Methanolic Extract: In Vitro and In Silico Screening of Its Antimicrobial, Antioxidant, Anti-Quorum Sensing, Antibiofilm, and Anticancer Activities

Thymus musilii Velen. is a rare plant species cultivated in the Ha'il region (Saudi Arabia) under greenhouse conditions. In this work, we described, for the first time, the phytochemical composition, antimicrobial, antioxidant, anti-quorum sensing, and anticancer activities of T. musilii methanolic extract using both experimental and computational approaches. The obtained results showed the identification of eight small-like peptides and eighteen phyto-compounds by using high-resolution liquid chromatography-mass spectrometry (HR-LCMS) dominated mainly by compounds belonging to isoprenoid, fatty acyl, flavonoid, and alkaloid classes. The tested extracts exhibited high antifungal and antibacterial activity with the mean diameter of growth inhibition zones ranging from 12.33 ± 0.57 mm (Pseudomonas aeruginosa ATCC 27853) to 29.33 ± 1.15 mm (Candida albicans ATCC 10231). Low minimal inhibitory concentrations were recorded for the tested micro-organisms ranging from 0.781 mg/mL to 12.5 mg/mL. While higher doses were necessary to completely kill all tested bacterial and fungal strains. Thyme extract was able to scavenge DPPH•, ABTS•+, β-carotene, and FRAP free radicals, and the IC50 values were 0.077 ± 0.0015 mg/mL, 0.040 ± 0.011 mg/mL, 0.287 ± 0.012 mg/mL, and 0.106 ± 0.007 mg/mL, respectively. The highest percentage of swarming and swimming inhibition was recorded at 100 µg/mL with 39.73 ± 1.5% and 25.18 ± 1%, respectively. The highest percentage of biofilm inhibition was recorded at 10 mg/mL for S. typhimurium ATCC 14028 (53.96 ± 4.21%) and L. monocytogenes ATCC 7644 (49.54 ± 4.5 mg/mL). The in silico docking study revealed that the observed antimicrobial, antioxidant, and anticancer activities of the constituent compounds of T. musilii are thermodynamically feasible, notably, such as those of the tripeptides (Asn-Met-His, His-Cys-Asn, and Phe-His-Gln), isoprenoids (10-Hydroxyloganin), and diterpene glycosides (4-Ketoretinoic acid glucuronide).

Multifunctional Derivatives of Spiropyrrolidine Tethered Indeno-Quinoxaline Heterocyclic Hybrids as Potent Antimicrobial, Antioxidant and Antidiabetic Agents: Design, Synthesis, In Vitro and In Silico Approaches

To combat emerging antimicrobial-resistant microbes, there is an urgent need to develop new antimicrobials with better therapeutic profiles. For this, a series of 13 new spiropyrrolidine derivatives were designed, synthesized, characterized and evaluated for their in vitro antimicrobial, antioxidant and antidiabetic potential. Antimicrobial results revealed that the designed compounds displayed good activity against clinical isolated strains, with 5d being the most potent (MIC 3.95 mM against Staphylococcus aureus ATCC 25923) compared to tetracycline (MIC 576.01 mM). The antioxidant activity was assessed by trapping DPPH, ABTS and FRAP assays. The results suggest remarkable antioxidant potential of all synthesized compounds, particularly 5c, exhibiting the strongest activity with IC₅₀ of 3.26 ± 0.32 mM (DPPH), 7.03 ± 0.07 mM (ABTS) and 3.69 ± 0.72 mM (FRAP). Tested for their α-amylase inhibitory effect, the examined analogues display a variable degree of α-amylase activity with IC₅₀ ranging between 0.55 ± 0.38 mM and 2.19 ± 0.23 mM compared to acarbose (IC₅₀ 1.19 ± 0.02 mM), with the most active compounds being 5d, followed by 5c and 5j, affording IC₅₀ of 0.55 ± 0.38 mM, 0.92 ± 0.10 mM, and 0.95 ± 0.14 mM, respectively. Preliminary structure–activity relationships revealed the importance of such substituents in enhancing the activity. Furthermore, the ADME screening test was applied to optimize the physicochemical properties and determine their drug-like characteristics. Binding interactions and stability between ligands and active residues of the investigated enzymes were confirmed through molecular docking and dynamic simulation study. These findings provided guidance for further developing leading new spiropyrrolidine scaffolds with improved dual antimicrobial and antidiabetic activities.

Development of Halogenated-Chalcones Bearing with Dimethoxy Phenyl Head as Monoamine Oxidase-B Inhibitors

Two series of dimethoxy-halogenated chalcones (DM1−DM20) were synthesized and tested for their ability to inhibit monoamine oxidase (MAOs). Compound DM2 exhibited the most significant inhibition against MAO-B with an IC50 value of 0.067 µM, followed by compound DM18 (IC50 = 0.118 µM), with selectivity index (SI) values of 93.88 and >338.98, respectively. However, none of the substances successfully inhibited MAO-A. The MAO-B inhibitors DM2 and DM18 were competitive and reversible, with Ki values of 0.032 ± 0.004 and 0.045 ± 0.001 µM, respectively. DM2 was non-toxic below 100 µg/mL in the cytotoxic test using the Vero epithelial cell line by the MTT method. According to molecular docking studies, DM2 and DM18 formed very similar conformations within the MAO-B binding pocket, with the ortho-chlorine and ortho-fluorine aromatic rings sandwiched between F168 and Y326. These conformations were predicted to show better interactions with the targeted MAO-B than MAO-A. In particular, the induced-fit docking of the dimethoxy phenyl ring of DM2 facing the hydrophobic pocket made up of FAD, Y398, and Y435 had an impact on F168 in the docking pocket. Taken together, DM2 and DM18 may be suitable candidates for treating neurodegenerative conditions such as Parkinson’s disease.