Acetylcholinesterase and butyrylcholinesterase inhibitory activities of khellactone coumarin derivatives isolated from Peucedanum japonicum Thurnberg

Phytochemical characterization and biological activities of Inula viscosa L. Aiton: a promising plant from Turkey

The methanol extract of Inula viscosa (IVM) was investigated for its antioxidant potential using the DPPH and ABTS radical scavenging as well as iron chelating assays (ICA). The total phenol (TPC) and flavonoid contents (TFC) of IVM were determined using the Folin-Ciocalteu and aluminum trichloride methods, respectively. Antimicrobial activity of different concentrations of I. viscosa methanol extract was investigated by disc diffusion and broth microdilution method. The IVM extract was found to be containing TPC (236.78 ± 7.63 mg GAE/g) and TFC (94.36 ± 1.86 mg QE/g). Antioxidant activity IC50 values for the DPPH, ABTS and ICA assays were found to be 277.7 ± 3.68, 2.44 ± 0.02, and 222.1 ± 0.71 µg/mL, respectively. The MIC values of the IVM on the tested microorganisms ranged from 0.48 to 7.81 mg/mL. Furthermore, IVM extract was demonstrated 18.32 ± 1.37%, 23.06 ± 1.05%, 4.72 ± 0.13%, 15.13 ± 0.37% and 37.64 ± 4.02% inhibition against tyrosinase, α-amylase, α-glucosidase, AChE and BChE, respectively. In the results of LC-MS/MS analysis, acacetin, quercetin, chlorogenic acid and protocatechuic acid were determined as most dominant compounds. These findings suggested that this plant may be a natural resource for creating novel medicinal compounds.

Unleashing new MTDL AChE and BuChE inhibitors as potential anti-AD therapeutic agents: In vitro, in vivo and in silico studies

Alzheimer's disease (AD) is challenging due to its irreversible declining cognitive symptoms and multifactorial nature. This work tackles targeting both acetylcholinesterase (AChE) and BuChE with a multitarget-directed ligand (MTDL) through design, synthesis, and biological and in silico evaluation of a series of twenty eight new 5-substituted-2-anilino-1,3,4-oxadiazole derivatives 4a-g, 5a-g, 9a-g and 13a-g dual inhibitors of the target biomolecules. In vitro cholinesterases inhibition and selectivity assay of the synthesized derivatives showed excellent nanomolar level inhibitory activities. Compound 5a, the most potent inhibitor, elicited IC50s of 46.9 and 3.5 nM against AChE and BuChE, respectively (SI = 0.07), 5 folds better than the known dual inhibitor Rivastagmine. In vivo and ex vivo investigation showed that 5a significantly inhibited MDA levels and increased GSH contents, thus, attenuating the brain tissue oxidative stress. Additionally, 5a significantly decreased AChE and BuChE levels and inhibited self-mediated β-amyloid aggregation in brains of treated rats. Histopathological and immunohistochemical evaluation demonstrated lessened damage and decreased caspase-3 and VEGF expression levels. In silico prediction of 5a's pharmacokinetics and toxicity profiles reflected promising results. Finally, 5a demonstrated tight binding interactions with the two target biomolecules upon docking along with stable complex formation with its bio-targets throughout the 100 ns MD trajectories.

Exploring the impact of novel thiazole-pyrazole fused benzo-coumarin derivatives on human serum albumin: Synthesis, photophysical properties, anti-cholinergic activity, and interaction studies

Derivatives of thiazole-pyrazole fused benzo-coumarin compounds were successfully synthesized and characterized, followed by a comprehensive spectroscopic investigation on various photophysical properties in different media. The multipronged approach using steady state and time resolved fluorescence spectroscopy pointed out the impact of substitution in the estimated spectroscopic and other physicochemical properties of the systems. Further, the evaluation of anti-acetylcholinesterase (anti-AChE) activity yielded significant insight into the therapeutic potential of the synthesized coumarinyl compounds for the treatment of Alzheimer's disease (AD). The findings revealed a non-competitive mode of inhibition mechanism, with an estimated IC50 value of 67.72 ± 2.00 nM observed for one of the investigated systems as AChE inhibitor. Notably, this value is even lower than that of an FDA-approved AD drug Donepezil (DON), indicating the enhanced potency of the coumarin derivatives in inhibiting AChE. Interestingly, significant diminution in inhibition was observed in presence of human serum albumin (HSA) as evidenced by the relative increase in IC50 value by 8 ∼ 39 % in different cases, which emphasized the role of albumin proteins to control therapeutic efficacies of potential medications. In-depth spectroscopic and in-silico analysis quantified the nature of interactions of the investigated systems with HSA and AChE. Overall, the outcomes of this study provide significant understanding into the biophysical characteristics of novel thiazole-pyrazole fused benzo-coumarin systems, which could aid in the development of new cholinergic agents for the treatment of AD and materials based on coumarin motifs.

An Integrated Computational Approaches for Designing of Potential Piperidine based Inhibitors of Alzheimer Disease by Targeting Cholinesterase and Monoamine Oxidases Isoenzymes

The study aimed to evaluate the potential of piperidine-based 2H chromen-2-one derivatives against targeted enzymes, i.e., cholinesterase's and monoamine oxidase enzymes. The compounds were divided into three groups, i.e., 4a-m ((3,4-dimethyl-7-((1-methylpiperidin-4-yl)oxy)-2H-chromen-2-one derivatives), 5a-e (3,4-dimethyl-7-((1-methypipridin-3-yl)methoxy)-2H-chromen-2-one derivatives), and 7a-b (7-(3-(3,4-dihydroisoquinolin-2(1H)-yl)propoxy)-3,4-dimethyl-2H-chromen-2-one derivatives) with slight difference in the basic structure. The comprehensive computational investigations were conducted including density functional theories studies (DFTs), 2D-QSAR studies, molecular docking, and molecular dynamics simulations. The QSAR equation revealed that the activity of selected chromen-2-one-based piperidine derivatives is being affected by the six descriptors, i.e., Nitrogens Count, SdssCcount, SssOE-Index, T-2-2-7, ChiV6chain, and SssCH2E-Index. These descriptor values were further used for the preparation of chromen-2-one based piperidine derivatives. Based on this, 83 new derivatives were created from 7 selected parent compounds. The QSAR model predicted their IC50 values, with compound 4 k and 4kk as the most potent multi-targeted derivative. Molecular docking results exhibited these compounds as the best inhibitors; however, 4kk exhibited greater activity than the parent compounds. The results were further validated by molecular dynamic simulation studies along with the suitable physicochemical properties. These results prove to be an essential guide for the further design and development of new piperidine based chromen-2-one derivatives having better activity against neurodegenerative disorder.

Metabolomics-based pharmaceutical evaluation of different parts of Swertia chirayita (Roxb.) Buch.-Ham. ex C.B. Clarke from the western Himalayas

Swertia species are common ingredients in numerous herbal remedies. It is also used to treat a wide range of illnesses and possess diverse therapeutic activities. The aim of the study is to elucidate the comprehensive metabolomics profile of Swertia chirayita and the role of various extraction methods in the phytochemical compositions of the extracts of S. chirayita, and their antioxidant and enzyme inhibitory activities. Extraction of the stems, leaves, and flowering tops of S. chirayita was performed by maceration, infusion, and soxhlation using methanol and water as solvent. Extracts were subjected to phytochemical profiling by a liquid-chromatographic system. Antioxidant and enzyme inhibitory activity was carried out. The metabolomics profiling showed that a diverse range of specialized metabolites were present in the stems and leaves & flowering tops of the plant. All the extracts showed substantial antioxidant and enzyme inhibitory activities further confirmed by molecular docking studies. This study appraised the use of S. chirayita aerial parts as a potential antioxidant and its therapeutic application in various chronic illnesses including Alzheimer's disease, diabetes, and other skin-related disorders.

13C NMR-based dereplication using MixONat software to decipher potent anti-cholinesterase compounds in Mesua lepidota bark

A bio-assay guided fractionation strategy based on cholinesterase assay combined with 13C NMR-based dereplication was used to identify active metabolites from the bark of Mesua lepidota. Eight compounds were identified with the aid of the 13C NMR-based dereplication software, MixONat, i.e., sitosterol (1), stigmasterol (2), α-amyrin (3), friedelin (6), 3β-friedelinol (7), betulinic acid (9), lepidotol A (10) and lepidotol B (11). Further bio-assay guided isolation of active compounds afforded one xanthone, pyranojacareubin (12) and six coumarins; lepidotol A (10), lepidotol B (11), lepidotol E (13), lepidotin A (14), and lepidotin B (15), including a new Mammea coumarin, lepidotin C (16). All the metabolites showed strong to moderate butyrylcholinesterase (BChE) inhibition. Lepidotin B (15) exhibited the most potent inhibition towards BChE with a mix-mode inhibition profile and a Ki value of 1.03 µM. Molecular docking and molecular dynamics simulations have revealed that lepidotin B (15) forms stable interactions with key residues within five critical regions of BChE. These regions encompass residues Asp70 and Tyr332, the acyl hydrophobic pocket marked by Leu286, the catalytic triad represented by Ser198 and His438, the oxyanion hole (OH) constituted by Gly116 and Gly117, and the choline binding site featuring Trp82. To gauge the binding strength of lepidotin B (15) and to pinpoint pivotal residues at the binding interface, free energy calculations were conducted using the Molecular Mechanics Generalized Born Surface Area (MM-GBSA) approach. This analysis not only predicted a favourable binding affinity for lepidotin B (15) but also facilitated the identification of significant residues crucial for the binding interaction.

Chemo- and bio-informatics insight into anti-cholinesterase potentials of berries and leaves of Myrtus communis L., Myrtaceae: an in vitro/in silico study

BACKGROUND

Myrtus communis L. (MC) has been used in Mesopotamian medicine. Here, the cholinesterase (ChE) inhibitory potential of its methyl alcohol extracts has been investigated and computationally dissected.

METHOD

The ChE inhibition has been measured based on usual Ellman's colorimetric method compared to a canonical ChE inhibitor, eserine. Through a deep text mining, the structures of phytocompounds (= ligands) of MC were curated from ChemSpider, PubChem, and ZINC databases and docked into protein targets, AChE (PDB 1EVE) and BChE (PDB 1P0I) after initial in silico preparedness and binding affinity (BA; kcal/mol) reported as an endpoint. The calculation of ADMET (absorption, distribution, metabolism, excretion, and toxicity) features of phytocompounds were retrieved from SwissADME ( http://www.swissadme.ch/ ) and admetSAR software to predict the drug-likeness or lead-likeness fitness. The Toxtree v2.5.1, software platforms ( http://toxtree.sourceforge.net/ ) have been used to predict the class of toxicity of phytocompounds. The STITCH platform ( http://stitch.embl.de ) has been employed to predict ChE-chemicals interactions.

RESULTS

The possible inhibitory activities of AChE of extracts of leaves and berries were 37.33 and 70.00%, respectively as compared to that of eserine while inhibitory BChE activities of extracts of leaves and berries of MC were 19.00 and 50.67%, respectively as compared to that of eserine. Phytochemicals of MC had BA towards AChE ranging from -7.1 (carvacrol) to -9.9 (ellagic acid) kcal/mol. In this regard, alpha-bulnesene, (Z)-gamma-Bisabolene, and beta-bourbonene were top-listed low toxic binders of AChE, and (Z)-gamma-bisabolene was a more specific AChE binder. Alpha-cadinol, estragole, humulene epoxide II, (a)esculin, ellagic acid, patuletin, juniper camphor, linalyl anthranilate, and spathulenol were high class (Class III) toxic substances which among others, patuletin and alpha-cadinol were more specific AChE binders. Among intermediate class (Class II) toxic substances, beta-chamigrene was a more specific AChE binder while semimyrtucommulone and myrtucommulone A were more specific BChE binders.

CONCLUSION

In sum, the AChE binders derived from MC were categorized mostly as antiinsectants (e.g., patuletin and alpha-cardinal) due to their predicted toxic classes. It seems that structural amendment and stereoselective synthesis like adding sulphonate or sulphamate groups to these phytocompounds may make them more suitable candidates for considering in preclinical investigations of Alzheimer's disease.

2-Oxoquinoline-based-thiosemicarbazones as multitargeting neurotherapeutics against Alzheimer's disease: In vitro and in silico studies of MAO and ChE inhibitors

Alzheimer's disease (AD) presents a multifactorial neurological disorder with multiple enzyme involvement in its onset. Conventional monotherapies fall short in providing long-term relief, necessitating the exploration of alternative multitargeting approaches to address the complexity of AD. Therefore, the design, synthesis, and in vitro and in silico evaluation of 2-oxoquinoline-based thiosemicarbazones 9a-r as multipotent analogs, able to simultaneously inhibit the cholinesterase (ChE) and monoamine oxidase (MAO) enzymes for the potential treatment of AD, are reported. In the in vitro experimental evaluation of MAO and ChE inhibition, all tested compounds demonstrated remarkable potency exhibiting nonselective inhibition of both MAO-A and MAO-B, and selective inhibition of acetylcholinesterase (AChE) over butyrylcholinesterase (BChE), with 9d, 9j, and 9m evolving as lead compounds for MAO-A, MAO-B, and AChE, displaying IC50 values of 0.35 ± 0.92, 0.50 ± 0.02, and 0.25 ± 0.13 μM, respectively. Moreover, the kinetic studies revealed that all tested compounds inhibited all three enzymes through a competitive mode of inhibition. Furthermore, the molecular docking studies of the most active compounds revealed several crucial interactions, particularly hydrogen bonding interactions. These interactions were observed between the nitrogen and sulfur atoms of thiosemicarbazone and the nitrogen and oxygen atoms of the quinoline ring with various amino acids, suggesting the strong interactions of these compounds with the enzymes.

Anti-inflammatory effects of Peucedanum japonicum Thunberg leaves extract in Lipopolysaccharide-stimulated RAW264.7 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Peucedanum japonicum Thunberg are perennial herbaceous plants known to be cultivated for food and traditional medicinal purposes. P. japonicum has been used in traditional medicine to soothe coughs and colds, and to treat many other inflammatory diseases. However, there are no studies on the anti-inflammatory effects of the leaves.

AIM OF THE STUDY

Inflammation plays an important role in our body as a defense response of biological tissues to certain stimuli. However, the excessive inflammatory response can lead to various diseases. This study aimed to investigate the anti-inflammatory effects of P. japonicum leaves extract (PJLE) in LPS-stimulated RAW 264.7 cells.

MATERIAL AND METHODS

Nitric Oxide (NO) production assay measured by NO assay. Inducible NO synthase (iNOS), COX-2, MAPKs, AKT, NF-κB, HO-1, Nrf-2 were examined by western blotting. PGE₂, TNF-α, and IL-6 were analyzed by ELSIA. Nuclear translocation of NF-κB was detected by immunofluorescence staining.

RESULTS

PJLE suppressed inducible nitric oxygen synthase (iNOS) and prostaglandin-endoperoxide synthase 2 (cyclooxygenase-2, COX-2) expression, increased heme oxygenase 1 (HO-1) expression, and decreased nitric oxide production. And PJLE inhibited the phosphorylation of AKT, MAPK, and NF-κB. Taken together, PJLE down-regulated inflammatory factors such as iNOS and COX-2 by inhibiting the phosphorylation of AKT, MAPK, and NF-κB.

CONCLUSIONS

These results suggest that PJLE can be used as a therapeutic material to modulate inflammatory diseases.

Phenolic Profile and Cholinesterase Inhibitory Properties of Three Chilean Altiplano Plants: Clinopodium gilliesii (Benth.) Kuntze [Lamiaceae], Mutisia acuminata Ruiz & Pav. var. hirsuta (Meyen) Cabrera, and Tagetes multiflora (Kunth) [Asteraceae]

This research aimed to identify the phenolic profile and composition of the aerial parts of three native species used in traditional medicine in the Andean Altiplano of northern Chile: Clinopodium gilliesii (Benth.) Kuntze [Lamiaceae] (commonly known as Muña-Muña), Mutisia acuminata Ruiz & Pav. var. hirsuta (Meyen) Cabrera [Asteraceae] (commonly known as Chinchircoma), and Tagetes multiflora (Kunth), [Asteraceae] (commonly known as Gracilis), as well as to evaluate their potential inhibitory effects against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Polyphenolic enriched-extracts (PEEs) of the species were prepared and analyzed and the main components were quantified using HPLC-DAD. In total, 30 phenolic compounds were identified and quantified in all species, including simple phenolics, hydroxycinnamic acids, flavan-3-ols (monomers and polymers), flavanones, and flavonols. In addition, other main phenolics from the extracts were tentatively identified by ESI-MS-MS high-resolution analysis. T. multiflora extract showed the greatest anti-AChE and BChE activity in comparison with C. gilliesii and M. acuminata extracts, being the anti-AChE and BChE activity weak in all extracts in comparison to galantamine control. To comprise to better understand the interactions between cholinesterase enzymes and the main phenolics identified in T. multiflora, molecular docking analysis was conducted.

Medicarpin and Homopterocarpin Isolated from Canavalia lineata as Potent and Competitive Reversible Inhibitors of Human Monoamine Oxidase-B

Thirteen compounds were isolated from the Canavalia lineata pods and their inhibitory activities against human monoamine oxidase-A (hMAO-A) and -B (hMAO-B) were evaluated. Among them, compounds 8 (medicarpin) and 13 (homopterocarpin) showed potent inhibitory activity against hMAO-B (IC₅₀ = 0.45 and 0.72 µM, respectively) with selectivity index (SI) values of 44.2 and 2.07, respectively. Most of the compounds weakly inhibited MAO-A, except 9 (prunetin) and 13. Compounds 8 and 13 were reversible competitive inhibitors against hMAO-B (K_i = 0.27 and 0.21 µM, respectively). Structurally, the 3-OH group at A-ring of 8 showed higher hMAO-B inhibitory activity than 3-OCH3 group at the A-ring of 13. However, the 9-OCH3 group at B-ring of 13 showed higher hMAO-B inhibitory activity than 8,9-methylenedioxygroup at the B-ring of 12 (pterocarpin). In cytotoxicity study, 8 and 13 showed non-toxicity to the normal (MDCK) and cancer (HL-60) cells and moderate toxicity to neuroblastoma (SH-SY5Y) cell. Molecular docking simulation revealed that the binding affinities of 8 and 13 for hMAO-B (-8.7 and -7.7 kcal/mol, respectively) were higher than those for hMAO-A (-3.4 and -7.1 kcal/mol, respectively). These findings suggest that compounds 8 and 13 be considered potent reversible hMAO-B inhibitors to be used for the treatment of neurological disorders.

Elbehairi S, Achar RR, Silina E, Stupin V, Manturova N, Glossman-Mitnik D, Shivamallu C, Kollur SP. Anticholinesterase activity of Areca Catechu: In Vitro and in silico green synthesis approach in search for therapeutic agents against Alzheimer's disease

For many years, the primary focus has been on finding effective treatments for Alzheimer's disease (AD), which has led to the identification of promising therapeutic targets. The necessity for AD stage-dependent optimal settings necessitated a herbal therapy strategy. The plant species Areca Catechu L. (AC) was selected based on the traditional uses against CNS-related diseases. AC leaf extract were prepared using a Soxhlet extraction method and hydroxyapatite nanoparticles (HAp-NPs) were synthesized from the same (AC-HAp-NPs). Powder X-ray diffractometer (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and fourier transform infrared spectroscopy (FTIR) were used to confirm the structure and morphology of the as-prepared AC-HAp-NPs. The crystalline character of the AC-HAp-NPs was visible in the XRD pattern. The synthesized material was found to be nanoflake, with an average diameter of 15-20 nm, according to SEM analysis. The TEM and SAED pictures also revealed the form and size of AC-HAp-NPs. In vitro anti-acetylcholinesterase and butyrylcholinesterase (AChE and BChE) activities of hydroxyapatite nanoparticles produced from an AC leaf extract was tested in this study. When compared to control, AC-HAp-NPs had higher anti-AChE and BChE activity. The anti-acetylcholinesterase action of phytoconstituents generated from AC leaf extract was mediated by 4AQD and 4EY7, according to a mechanistic study conducted utilizing in silico research. The global and local descriptors, which are the underpinnings of Conceptual Density Functional Theory (CDFT), have been predicted through the MN12SX/Def2TZVP/H2O model chemistry to help in the comprehension of the chemical reactivity properties of the five ligands considered in this study. The CDFT experiments are supplemented by the calculation of several useful calculated pharmacokinetics indices, their expected biological targets connected to the bioavailability of the five ligands in order to further the goal of studying their bioactivity.

Comparative Analysis of Coumarin Profiles in Different Parts of Peucedanum japonicum and Their Aldo-Keto Reductase Inhibitory Activities

Peucedanum japonicum (Umbelliferae) is widely distributed throughout Southeast Asian countries. The root of this plant is used in traditional medicine to treat colds and pain, whereas the young leaves are considered an edible vegetable. In this study, the differences in coumarin profiles for different parts of P. japonicum including the flowers, roots, leaves, and stems were compared using ultra-performance liquid chromatography time-of-flight mass spectrometry. Twenty-eight compounds were tentatively identified, including three compounds found in the genus Peucedanum for the first time. Principal component analysis using the data set of the measured mass values and intensities of the compounds exhibited distinct clustering of the flower, leaf, stem, and root samples. In addition, their anticancer activities were screened using an Aldo-keto reductase (AKR)1C1 assay on A549 human non-small-cell lung cancer cells and the flower extract inhibited AKR1C1 activity. Based on these results, seven compounds were selected as potential markers to distinguish between the flower part versus the root, stem, and leaf parts using an orthogonal partial least-squares discriminant analysis. This study is the first to provide information on the comparison of coumarin profiles from different parts of P. japonicum as well as their AKR1C1 inhibitory activities. Taken together, the flowers of P. japonicum offer a new use related to the efficacy of overcoming anticancer drug resistance, and may be a promising source for the isolation of active lead compounds.

Pharmacophore based virtual screening of cholinesterase inhibitors: search of new potential drug candidates as antialzheimer agents

Alzheimer’s disease (AD) is a distinctive medical condition characterized by loss of memory, orientation, and cognitive impairments, which is an exceptionally universal form of neurodegenerative disease. The statistical data suggested that it is the 3rd major cause of death in older persons. Butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) inhibitors play a vital role in the treatment of AD. Coumarins, natural derivatives, are reported as cholinesterase inhibitors and emerges as a promising scaffold for design of ligands targeting enzymes and pathological alterations related to AD. In this regard, the 3D QSAR pharmacophore models were developed for coumarin scaffold containing BChE and AChE inhibitors. Several 3D QSAR pharmacophore models were developed with FAST, BEST, and CEASER methods, and finally, statistically robust models (based on correlation coefficient, cost value, and RMSE value) were selected for further analysis for both targets. The important features ((HBA 1, HBA 2, HY, RA (BChE) HBA 1, HBA 2, HY, PI, (AChE)) were identified for good inhibitory activity of coumarin derivatives. Finally, the selected models were applied to various database compounds to find potential BChE and AChE inhibitors, and we found 13 for BChE and 1 potent compound for AChE with an estimated activity of IC₅₀ < 10 µM. Further, the Lipinski filters, and ADMET analysis supports the selected compounds to become a drug candidate. These selected BChE and AChE inhibitors can be used in the treatment of AD.

Inhibition of Cholinesterases by Benzothiazolone Derivatives

Thirteen benzothiazolone derivatives (M1–M13) were synthesized and evaluated for their inhibitory activity against cholinesterases (ChEs) and monoamine oxidases (MAOs). All the compounds inhibited ChEs more effectively than MAOs. In addition, most of the compounds showed higher inhibitory activities against butyrylcholinesterase (BChE) than acetylcholinesterase (AChE). Compound M13 most potently inhibited BChE with an IC50 value of 1.21 μM, followed by M2 (IC50 = 1.38 μM). Compound M2 had a higher selectivity index (SI) value for BChE over AChE (28.99) than M13 (4.16). The 6-methoxy indole group of M13 was expected to have a greater effect on BChE inhibitory activity than the other groups. Kinetics and reversibility tests showed that M13 was a reversible noncompetitive BChE inhibitor with a Ki value of 1.14 ± 0.21 μM. In a docking simulation, M13 is predicted to form a hydrogen bond with the backbone carbonyl group of Ser287 of BChE through its methoxy indole moiety and π−π interactions between its benzothiazolone group and the side chain of Trp82 with the five-membered pyrrole ring and with the six-membered benzene ring. From these results, it is suggested that M13 is a BChE inhibitor and a potential candidate agent for the treatment of Alzheimer’s disease.

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.

Synthesis of 4-substituted benzyl-2-triazole-linked-tryptamine-paeonol derivatives and evaluation of their selective inhibitions against butyrylcholinesterase and monoamine oxidase-B

Cholinesterase (ChE) and monoamine oxidase (MAO) inhibitors are being used and developed to treat Alzheimer's disease (AD), a major type of dementia patients. Fifteen 4-substituted benzyl-2-triazole-linked-tryptamine-paeonol derivatives were synthesized and evaluated for their inhibitory activities against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), monoamine oxidase-A (MAO-A), and B (MAO-B). Compound 896 was the most potent BChE inhibitor (IC₅₀ = 0.13 μM) with the selectivity index (SI) value of >769.23 for BChE over AChE. Compound 897 was the most potent selective MAO-B inhibitor (IC₅₀ = 0.73 μM; SI = 20.45 for MAO-B over MAO-A). The meta-CF₃ substituent of 896 increased BChE inhibitory activity and the para-CF₃ substituent of 897 increased MAO-B inhibitory activity. Compound 896 was a reversible noncompetitive BChE inhibitor (K_i = 0.171 μM) and 897 was a reversible competitive MAO-B inhibitor (K_i = 0.237 μM). Compound 896 had a lower binding energy (-13.75 kcal/mol) to BChE than 897 (-11.29 kcal/mol), and 897 had a lower binding energy to MAO-B (-11.31 kcal/mol) than that to MAO-A (-6.72 kcal/mol). Little cytotoxicity was observed for 896 and 897 to normal cells (MDCK) and human neuroblastoma cells (SH-SY5Y). This study suggested that 896 and 897 are therapeutic candidates for various neurodegenerative disorders such as AD.

Inhibition of influenza virus replication by Apiaceae plants, with special reference to Peucedanum japonicum (Sacna) constituents

ETHNOPHARMACOLOGICAL RELEVANCE

Apiaceae plants possess various pharmacological properties, such as antimicrobial, antioxidant, hypoglycemic, hypolipidemic, anxiolytic, analgesic, anti-inflammatory, anti-convulsant, and anti-cancer activities; however, data on their antiviral activity are limited. Peucedanum japonicum, also known as Sacna, is a plant used as food and as a traditional folk medicine for treating coughs. However, the active components in the leaves of this plant are yet unexplored.

AIM OF THE STUDY

To assess Apiaceae plants, especially Peucedanum japonicum, with anti-viral activity, and the function and antiviral potential of Sacna constituents, considering the emergence of influenza virus strains resistant to the currently available drugs.

MATERIALS AND METHODS

We prepared grinds of the freeze-dried leaves and roots of the Apiaceae family and the hot water extracts. The antiviral activities of the extracts were determined by focus formation reduction assay. In the time-of-addition assay, the test medium containing Sacna extract at 2 mg/mL was added at -1 to 0 h (adsorption) or from 0 to 4, 4 to 8, or 0 to 8 h (replication). The Sacna extract was separated by reversed-phase flash column chromatography using an Isolera Spektra system. The antiviral activity of each fraction was then determined using the focus formation reduction assay. The active fraction was analyzed using an LC20ADXR high performance liquid chromatography system equipped with a microTOF-QII quadrupole time-of-flight tandem mass spectrometer.

RESULTS

All examined extracts of Apiaceae plants showed anti-influenza activity. Sacna extract most strongly inhibited the replication of influenza viruses. Individual components of Sacna possess antiviral activities against the influenza A/PR/8/34 virus. Sacna was found to inhibit the multiplication of A (H1N1 and H3N2) types and B types of influenza viruses, including amantadine-resistant and oseltamivir-resistant viruses. Sacna also inhibited influenza infection during viral replication. However, Sacna did not inhibit influenza infection during cell adsorption and did not suppress hemagglutination inhibition or cell fusion. Further, our findings suggest that the antiviral compounds in Sacna include flavonoids (quercetin and luteolin) and other polyphenols (caffeic acid, hymecromone, and umbelliferone). Although several effective compounds in Sacna inhibit multiple steps of viral replication, caffeic acid, which was increased by heat treatment at the time of extraction, significantly inhibited only the late period of viral growth, similar to the Sacna extract, indicating that it is the major component responsible for the antiviral activity of Sacna.

CONCLUSIONS

Apiaceae plants possess antiviral activity. Caffeic acid is the major component responsible for the antiviral activity of Sacna. To our knowledge, this is the first report regarding the anti-influenza virus activity of Sacna. Overall, these results indicate that Sacna has potential as a novel treatment against influenza A and B viruses.

Development of a Novel Class of Pyridazinone Derivatives as Selective MAO-B Inhibitors

Sixteen compounds (TR1-TR16) were synthesized and evaluated for their inhibitory activities against monoamine oxidase A and B (MAOs). Most of the derivatives showed potent and highly selective MAO-B inhibition. Compound TR16 was the most potent inhibitor against MAO-B with an IC₅₀ value of 0.17 μM, followed by TR2 (IC₅₀ = 0.27 μM). TR2 and TR16 selectivity index (SI) values for MAO-B versus MAO-A were 84.96 and higher than 235.29, respectively. Compared to the basic structures, the para-chloro substituent in TR2 and TR16 increased the inhibitory activity of MAO-B. TR2 and TR16 were reversible MAO-B inhibitors that were competitive, with K_i values of 0.230 ± 0.004 and 0.149 ± 0.016 µM, respectively. The PAMPA method indicated that compounds TR2 and TR16 had the tendency to traverse the blood-brain barrier. Docking investigations revealed that lead compounds were beneficial for MAO-B inhibition via association with key as well as selective E84 or Y326 residues, but not for MAO-A inhibition via interaction primarily driven by hydrophobic contacts. In conclusion, TR2 and TR16 are therapeutic prospects for the management of multiple neurodegenerative diseases.

Evaluation of Inhibitory Activities of Sophora flavescens and Angelica gigas Nakai Root Extracts against Monoamine Oxidases, Cholinesterases, and β-Secretase

In this study, Sophora flavescens (SF) from Yeongcheon (YSF) and Mt. Jiri (JiSF), and Angelica gias (AG) from Yeongcheon (YAG), Mt. Jiri (JiAG), and Jecheon (JeAG) were extracted using three concentrations of ethanol, 95% (95Et), 70% (70Et), and 50% (50Et), and hot water (DW) to evaluate the inhibitions of monoamine oxidases (MAOs; MAO-A and B), cholinesterases (ChEs; AChE and BChE) and β-secretase (BACE1) for targeting depression and neurodegenerative diseases. There were no significant differences in constituent compounds depending on herbal origins, except that YSF-95Et and JiSF-95Et showed a distinct non-polar spot upper maackiain position, and JiAG and JeAG showed a higher amount of decursin than YAG. Ethanolic YAG and JeAG extracts showed the highest MAO-A inhibition, and YSF-95Et mostly inhibited MAO-B. JiSF-95Et showed the highest AChE inhibition and YSF-70Et, JiSF-95Et, and -70Et showed the highest BChE inhibition. Interestingly, ethanolic AG extracts showed extremely potent BACE1 inhibition, especially for JiAG-95Et and JeAG-50Et, whereas there have been no reports about BACE1 inhibition of decursin, the major compound, or AG extracts in other studies. All extracts were nontoxic to MDCK and SH-SY5Y with a low toxicity to HL-60. The results showed a different pattern of inhibitory activities of the extracts toward target enzymes depending on the origins, and multi-target abilities, especially for MAO-B and BChE by YSF-95Et, for AChE and BChE by JiSF-95Et, and for MAO-B and BACE1 by JiAG-95Et. It is suggested that those extracts are potential candidates for finding novel compounds with multi-target inhibitory activities, and herbal origin is an important factor to be considered in selection of the plants.

Conjugated Dienones from Differently Substituted Cinnamaldehyde as Highly Potent Monoamine Oxidase-B Inhibitors: Synthesis, Biochemistry, and Computational Chemistry

Fifteen multiconjugated dienones (MK1-MK15) were synthesized and evaluated to determine their inhibitory activities against monoamine oxidases (MAOs) A and B. All derivatives were found to be potent and highly selective MAO-B inhibitors. Compound MK6, with an IC₅₀ value of 2.82 nM, most effectively inhibited MAO-B, like MK12 (IC₅₀ = 3.22 nM), followed by MK5, MK13, and MK14 (IC₅₀ = 4.02, 4.24, and 4.89 nM, respectively). The selectivity index values of MK6 and MK12 for MAO-B over MAO-A were 7361.5 and 1780.5, respectively. Compounds MK6 and MK12 were competitive reversible inhibitors of MAO-B, with K _i values of 1.10 ± 0.20 and 3.0 ± 0.27 nM, respectively. Cytotoxic studies showed that MK5, MK6, MK12, and MK14 exhibited low toxicities on Vero cells, with IC₅₀ values of 218.4, 149.1, 99.96, and 162.3 μg/mL, respectively, which were much higher than those for their effective nanomolar-level concentrations. Also, MK5, MK6, MK12, and MK14 decreased cell damage in H₂O₂-induced cells via a significant scavenging effect of reactive oxygen species. Molecular modeling was performed to rationalize the potential inhibitory activities of MK5, MK6, MK12, and MK14 toward MAO-B and their possible binding mechanisms, showing high-affinity binding pocket interactions and conformation perturbations of the compounds with MAO-B, which were interpreted as the conformational dynamics of MAO-B. This study concluded that all the compounds tested were more potent MAO-B inhibitors than the reference drugs, and leading compounds could be further explored for their effectiveness in various kinds of neurodegenerative disorders.

Alkaloid Profiling, Anti-Enzymatic and Antiproliferative Activity of The Endemic Chilean Amaryllidaceae Phycella cyrtanthoides

This research aims to identify the alkaloid profile and to evaluate the enzyme inhibitory potential and antiproliferative effects of the Amaryllidaceae plant Phycella cyrtanthoides. The alkaloid extracts from bulbs and leaves were analyzed using ultrahigh performance liquid chromatography orbitrap mass spectrometry (UHPLC-Orbitrap-MS) analysis. A total of 70 alkaloids were detected in the P. cyrtanthoides’ extracts. The enzyme inhibition potential against cholinesterases (AChE: acetylcholinesterase, and BChE butyrylcholinesterase) and tyrosinase were studied. Bulbs displayed the best IC₅₀ values against AChE (4.29 ± 0.03 µg/mL) and BChE (18.32 ± 0.03 µg/mL). These results were consistent with docking experiments with selected major compounds in the active sites of enzymes, while no activity was observed against tyrosinase enzyme. Antiproliferative effects were investigated against human cervical (HeLa), lung (A549, SW1573), colon (WiDr), and breast (HBL-100, T-47D) tumor cell lines. Bulbs and leaves were active in all cell lines (GI₅₀ < 2.5 µg/mL). These findings suggest that the endemic Chilean plant P. cyrtanthoides contains diverse types of bioactive alkaloids with antiproliferative activities and inhibitory effects with potential therapeutic applications for neurodegenerative diseases

Novel thiophene Chalcones-Coumarin as acetylcholinesterase inhibitors: Design, synthesis, biological evaluation, molecular docking, ADMET prediction and molecular dynamics simulation

A series of around eight novel chalcone based coumarin derivatives (23a-h) was designed, subjected to in-silico ADMET prediction, synthesized, characterized by IR, NMR, Mass analytical techniques and evaluated as acetylcholinesterase (AChE) inhibitor for the treatment of Alzheimer's disease (AD). The results of predicted ADMET study demonstrated the drug-likeness properties of the titled compounds with developmental challenges in lipophilicity and solubility parameters. The in vitro assessment of the synthesized compounds revealed that all of them showed significant activity (IC₅₀ ranging from 0.42 to 1.296 µM) towards AChE compared to the standard drug, galantamine (IC₅₀ = 1.142 ± 0.027 µM). Among these, compound 23e displayed the most potent inhibitory activity with IC₅₀ value of 0.42 ± 0.019 µM. Cytotoxicity of all compounds was tested on normal human hepatic (THLE-2) cell lines at three different concentrations using the MTT assay, in which none of the compound showed significant toxicity at the highest concentration of 1000 µg/ml compared to the control group. Based on the docking study against AChE, the most active derivative 23e was orientated towards the active site and occupied both catalytic anionic site (CAS) and peripheral anionic site (PAS) of the target enzyme. In-silico studies revealed tested showed better inhibition activity of AChE compared to Butyrylcholinesterase (BuChE). Molecular dynamics simulation explored the stability and dynamic behavior of 23e- AChE complex.

Selected Class of Enamides Bearing Nitro Functionality as Dual-Acting with Highly Selective Monoamine Oxidase-B and BACE1 Inhibitors

A small series of nitro group-bearing enamides was designed, synthesized (NEA1–NEA5), and evaluated for their inhibitory profiles of monoamine oxidases (MAOs) and β-site amyloid precursor protein cleaving enzyme 1 (β-secretase, BACE1). Compounds NEA3 and NEA1 exhibited a more potent MAO-B inhibition (IC₅₀ value = 0.0092 and 0.016 µM, respectively) than the standards (IC₅₀ value = 0.11 and 0.14 µM, respectively, for lazabemide and pargyline). Moreover, NEA3 and NEA1 showed greater selectivity index (SI) values toward MAO-B over MAO-A (SI of >1652.2 and >2500.0, respectively). The inhibition and kinetics studies suggested that NEA3 and NEA1 are reversible and competitive inhibitors with K_i values of 0.013 ± 0.005 and 0.0049 ± 0.0002 µM, respectively, for MAO-B. In addition, both NEA3 and NEA1 showed efficient BACE1 inhibitions with IC₅₀ values of 8.02 ± 0.13 and 8.21 ± 0.03 µM better than the standard quercetin value (13.40 ± 0.04 µM). The parallel artificial membrane permeability assay (PAMPA) method demonstrated that all the synthesized derivatives can cross the blood–brain barrier (BBB) successfully. Docking analyses were performed by employing an induced-fit docking approach in the GLIDE module of Schrodinger, and the results were in agreement with their in vitro inhibitory activities. The present study resulted in the discovery of potent dual inhibitors toward MAO-B and BACE1, and these lead compounds can be fruitfully explored for the generation of newer, clinically active agents for the treatment of neurodegenerative disorders.

Non-Alkaloid Cholinesterase Inhibitory Compounds from Natural Sources

Alzheimer's disease (AD) is a severe neurodegenerative disorder of different brain regions accompanied by distresses and affecting more than 25 million people in the world. This progressive brain deterioration affects the central nervous system and has negative impacts on a patient's daily activities such as memory impairment. The most important challenge concerning AD is the development of new drugs for long-term treatment or prevention, with lesser side effects and greater efficiency as cholinesterases inhibitors and the ability to remove amyloid-beta(Aβ) deposits and other related AD neuropathologies. Natural sources provide promising alternatives to synthetic cholinesterase inhibitors and many have been reported for alkaloids while neglecting other classes with potential cholinesterase inhibition. This review summarizes information about the therapeutic potential of small natural molecules from medicinal herbs, belonging to terpenoids, coumarins, and phenolic compounds, and others, which have gained special attention due to their specific modes of action and their advantages of low toxicity and high efficiency in the treatment of AD. Some show superior drug-like features in comparison to synthetic cholinesterase inhibitors. We expect that the listed phytoconstituents in this review will serve as promising tools and chemical scaffolds for the discovery of new potent therapeutic leads for the amelioration and treatment of Alzheimer's disease.

Acetylcholinesterase and monoamine oxidase-B inhibitory activities by ellagic acid derivatives isolated from Castanopsis cuspidata var. sieboldii

Among 276 herbal extracts, a methanol extract of Castanopsis cuspidata var. sieboldii stems was selected as an experimental source for novel acetylcholinesterase (AChE) inhibitors. Five compounds were isolated from the extract by activity-guided screening, and their inhibitory activities against butyrylcholinesterase (BChE), monoamine oxidases (MAOs), and β-site amyloid precursor protein cleaving enzyme 1 (BACE-1) were also evaluated. Of these compounds, 4'-O-(α-L-rhamnopyranosyl)-3,3',4-tri-O-methylellagic acid (3) and 3,3',4-tri-O-methylellagic acid (4) effectively inhibited AChE with IC₅₀ values of 10.1 and 10.7 µM, respectively. Ellagic acid (5) inhibited AChE (IC₅₀ = 41.7 µM) less than 3 and 4. In addition, 3 effectively inhibited MAO-B (IC₅₀ = 7.27 µM) followed by 5 (IC₅₀ = 9.21 µM). All five compounds weakly inhibited BChE and BACE-1. Compounds 3, 4, and 5 reversibly and competitively inhibited AChE, and were slightly or non-toxic to MDCK cells. The binding energies of 3 and 4 (- 8.5 and - 9.2 kcal/mol, respectively) for AChE were greater than that of 5 (- 8.3 kcal/mol), and 3 and 4 formed a hydrogen bond with Tyr124 in AChE. These results suggest 3 is a dual-targeting inhibitor of AChE and MAO-B, and that these compounds should be viewed as potential therapeutics for the treatment of Alzheimer's disease.