Β-secretase Enzyme Research Articles

BACE1 inhibitors: A promising therapeutic approach for the management of Alzheimer’s disease

Alzheimer’s disease is a neurological disorder marked by the accumulation of amyloid beta (Aβ) aggregates, resulting from mutations in the amyloid precursor protein. The enzyme β-secretase, also known as β-site amyloid precursor protein cleaving enzyme 1 (BACE1), plays a crucial role in generating Aβ peptides. With no targeted therapy available for Alzheimer’s disease, inhibiting BACE1 aspartic protease has emerged as a primary treatment target. Since 1999, compounds demonstrating potential binding to the BACE1 receptor have advanced to human trials. Structural optimization of synthetically derived compounds, coupled with computational approaches, has offered valuable insights for developing highly selective leads with drug-like properties. This review highlights pivotal studies on the design and development of BACE1 inhibitors as anti-Alzheimer’s disease agents. It summarizes computational methods employed in facilitating drug discovery for potential BACE1 inhibitors and provides an update on their clinical status, indicating future directions for novel BACE1 inhibitors. The promising clinical results of Elenbecestat (E-2609) catalyze the development of effective, selective BACE1 inhibitors in the future.

Quercetagetin 3,7 dimethyl ether polymorphs as multi-targeted anti-amyloid agents: Target to cognitive impairment in Alzheimer's disease

The extraction of biologically active natural products from plants and the assessment of their medicinal properties play a crucial role in drug development. Taking that into consideration, the current research work was designed. Bioassay-guided isolation from Parthenium hysterophorus led to the isolation of two antioxidant compounds: polymorphs A (1) and B (2) of Quercetagetin 3,7-dimethyl ether which demonstrated IC50 values 13.00 ± 0.63 μM and 16.56 ± 0.82 μM, respectively in the DPPH assay. These polymorphs were further evaluated for their inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. In silico studies, including molecular docking, and molecular dynamic simulations were conducted using β-secretase, γ-secretase, AChE, and BChE enzymes. Interestingly, compound 1 demonstrated excellent antioxidant activity and showed the better binding affinities -9.0 kcal/mol (BChE), −8.5 kcal/mol (β-secretase), -8.2 kcal/mol (γ-secretase) and -7.7 kcal/mol (AChE) as compared to compound 2. Due to these promising results, compound 1 was selected for molecular dynamic simulations to further evaluate the stability and flexibility of its complexes. Overall, both in silico and in vitro results confirmed that compound 1 and compound 2 exhibit distinct behavior, making them promising candidates as antioxidants and inhibitors of AChE, BChE, and secretases, potentially targeting cognitive impairment in Alzheimer's disease (AD).

Lead optimization based design, synthesis, and pharmacological evaluation of quinazoline derivatives as multi-targeting agents for Alzheimer's disease treatment

The complexity and multifaceted nature of Alzheimer's disease (AD) have driven us to further explore quinazoline scaffolds as multi-targeting agents for AD treatment. The lead optimization strategy was utilized in designing of new series of derivatives (AK-1 to AK-14) followed by synthesis, characterization, and pharmacological evaluation against human cholinesterase's (hChE) and β-secretase (hBACE-1) enzymes. Amongst them, compounds AK-1, AK-2, and AK-3 showed good and significant inhibitory activity against both hAChE and hBACE-1 enzymes with favorable permeation across the blood-brain barrier. The most active compound AK-2 revealed significant propidium iodide (PI) displacement from the AChE-PAS region and was non-neurotoxic against SH-SY5Y cell lines. The lead molecule (AK-2) also showed Aβ aggregation inhibition in a self- and AChE-induced Aβ aggregation, Thioflavin-T assay. Further, compound AK-2 significantly ameliorated Aβ-induced cognitive deficits in the Aβ-induced Morris water maze rat model and demonstrated a significant rescue in eye phenotype in the Aꞵ-phenotypic drosophila model of AD. Ex-vivo immunohistochemistry (IHC) analysis on hippocampal rat brains showed reduced Aβ and BACE-1 protein levels. Compound AK-2 suggested good oral absorption via pharmacokinetic studies and displayed a good and stable ligand-protein interaction in in-silico molecular modeling analysis. Thus, the compound AK-2 can be regarded as a lead molecule and should be investigated further for the treatment of AD.

Effects of Exercise Training and L-Arginine Loaded Chitosan Nanoparticles on Hippocampus Histopathology, β-Secretase Enzyme Function, APP, Tau, Iba1and APOE-4 mRNA in Aging Rats.

The objective of this study was to evaluate the combined and independent effects of exercise training and L-Arginine loaded chitosan nanoparticles (LA CNPs) supplementation on hippocampal Tau, App, Iba1, and ApoE gene expression, oxidative stress, β-secretase enzyme activity, and hippocampus histopathology in aging rats. Thirty-five male Wistar rats were randomly assigned to five groups (n = 7 in each): Young (8 weeks old), Old (20 months old), old + L-arginine supplementation (Old Sup), old + exercise (Old Exe) and old + L-arginine supplementation + exercise (Old Sup + Exe). LA CNPs were administered to the supplement groups through gavage at a dosage of 500mg/kg/day for 6-weeks. Exercise groups were subjected to a swimming exercise program five days/week for the same duration. Upon the completion of their interventions, the animals underwent behavioral and open-field task tests and were subsequently sacrificed for hippocampus genetic and histopathological evaluation. For histopathological analysis of brain, Cresyl violet staining was used. Congo Red staining was employed to confirm amyloid plaques in the hippocampus. Expressions of Tau, App, Iba1, and ApoE genes were determined by real-time PCR. In contrast to the Old group, Old Exe and Old Sup + Exe groups spent more time in the central space in the open field task (p < 0.05) and have more live cells in the hippocampus. Old rats (Old, Old Sup and Old Exe groups) exhibited a significant Aβ peptide accumulation and increases in APP, Tau, Iba1, APOE-4 mRNA and MDA, along with decreases in SOD compared to the young group (p < 0.05). However, LA CNPs supplementation, exercise, and their combination (Old Sup, Old Exe and Old Sup + Exe) significantly reduced MDA, Aβ plaque as well as APP, Tau, Iba1, and APOE-4 mRNA compared to the Old group (p < 0.05). Consequently, the administration of LA CNPs supplements and exercise might regulate the risk factors of hippocampus cell and tissue.

Molecular docking analysis of marine phytochemicals with BACE-1.

Alzheimer's disease (AD), a debilitating neurodegenerative condition, is characterized by progressive cognitive decline brought about by the deposition of amyloid beta (Aβ) plaques in the brain initiates downstream neuronal dysfunction and death in AD pathogenesis. The β-secretase (BACE-1) enzyme plays a crucial role in generating Aβ from amyloid precursor protein (APP). Hence, we report the virtual screening of marine phytochemicals as BACE-1 inhibitors. 2583 compounds, retrieved from Comprehensive Marine Natural Product Database (CMNPD), were primarily screened for drug-likeliness and blood-brain barrier permeability using admetSAR 2.0 and in-house BBBper tool and resulted in a total of 635 phytochemicals, selected for further docking studies using BACE-1 as target receptor and Atabecestat as standard BACE-1 inhibitor. Seven of 635 compounds docked against BACE-1, showed better binding affinities than Atabecestat, with the red algal metabolite lactodehydrothyrsiferol showing lowest binding energy of -10.83 kcal/mol. These compounds are worth investigating further to assess their neuroprotective efficacy and pharmacokinetic properties. The study also provides a rational framework to uncover novel pharmacophores from marine sources for AD therapy acting through BACE-1 inhibition.

Computational screening of foxtail millet (Setaria italica (L.) P.Beauv.) polyphenols for finding β-secretase (BACE 1) inhibitors that target the amyloidogenic pathway in Alzheimer's disease

Abstract BACKGROUND: Foxtail millet (FM; Setaria italica (L.) P.Beauv.) is known for its antioxidant and neuroprotective action against Alzheimer's disease (AD); hence the present study aims to screen its polyphenols to find less toxic and potentially effective anti-Alzheimer's drugs. MATERIALS AND METHODS: The details about phyto-compounds of FM and the β-secretase enzyme (BACE 1) of AD have been retrieved from the PubChem compound database and protein data bank, respectively. The Patch Dock server was used to carry out docking experiments. Initially, all the FM phytocompounds and reference drug (MK-8931) were subjected to docking, and subsequently, the best-docked complexes were selected based on their binding energy (in kcal/mol). Rule of five and adsorption, distribution, metabolism, excretion, and toxicity (ADMET) of selected compounds were analyzed using various computational tools. The final docking complexes were developed by using PyMOL. RESULTS: The molecular docking results revealed that among the 24 polyphenols studied, two compounds, namely N′-p-coumaroyl-N″-caffeoylspermidine (NPCNCS) and di-P-coumaroylspermidine (DPCS), demonstrated strong binding to the active site of β-secretase. and exhibited higher binding energies of -300.75 kcal/mol and -193.41 kcal/mol, respectively, in comparison to the reference drug MK-8931, with a binding energy of -154.36 kcal/mol. These compounds established hydrogen bond interactions with catalytic dyad (Asp 32 and Asp 228) and other accessory interactions with residues of the “flap” hairpin loop and “10s loop” of the β-secretase active site involved in the stabilization of substrate/inhibitor binding. In a nutshell, the NPCNCS and DPCS have shown more robust binding affinity than MK-8931 and docked well into the interior side of the active site. On the other hand, NPCNCS and DPCS have satisfied the RO5 and ADMET filters. CONCLUSIONS: The in silico analysis of FM polyphenols revealed that the N′-p-coumaroyl-N″-feruloylspermidine and di-P-coumaroylspermidine compounds exhibited non-toxic, permeability to blood-brain barrier and solid binding affinity toward β-secretase enzyme thereby; these millet compounds might be considered as β-secretase inhibitors for treating AD.

Probing the multitargeting potential of n-hexane fraction of Gongronema latifolium leaves in neurodegeneration via in vitro, GC–MS and in silico studies

BackgroundNeurodegenerative disorders (NDDs) are associated with increased activities of brain acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and monoamine oxidase (MAO) as well as Aβ-amyloid (Aβ) neurotoxicity; therefore, they offer a therapeutic option for the treatment of NDDs such as Alzheimer’s disease (AD). This study was aimed at identifying multi-targeting neurotherapeutics from Gongronema latifolium leaves using in vitro analysis, GC–MS profiling and computational methods.ResultsThe n-hexane solvent partition fraction of the methanol extract of Gongronema latifolium leaf (HF) exhibited concentration-dependent inhibitory activities against acetylcholinesterase and butyrylcholinesterase but not against MOA in vitro. The GC–MS chemical profiling identified 17 phytochemicals from the HF; these were further screened against human AChE, BChE, β-secretase enzyme (BACE1) and amyloid-β (Aβ) fibrils using molecular docking, ensemble-based docking (EBD), molecular dynamics simulation (MDs) and binding free energy (BFG) coupled with predictive adsorption, distribution, metabolism, excretion and toxicity (ADMET) analysis. The lead phytochemicals (LPs) (dihydroactinidiolide and 1H-Indole-3-ethanamine), with mean binding energies (− 6.525 ± 0.895 and 6.475 ± 0.985; − 6.833 ± 0.461 and − 6.466 ± 0.577; − 6.2 ± 0.845 and − 5.95 ± 0.353 kcal/mol) exhibited multi-target binding tendencies to the catalytic residues of hAChE, hBChE and hBACE1, in addition to hAβ fibril-disruptive tendencies (− 6.325 ± 0.545 and − 5.95 ± 0.353 kcal/mol), respectively. These results corroborated the initial molecular docking and BFG computations. The lead phytochemical–protein complexes were stable during the period of MDs. The LP presented favorable drug-likeness and ADMET properties coupled with the capacity to traverse the BBB.ConclusionDihydroactinidiolide and 1H-Indole-3-ethanamine, in part or in synergy, are identified as neurotherapeutic constituents of Gongronema latifolium that may have been responsible for the ethnopharmacologically reported neurotherapeutic activities of the leaf, and hence they are suggested as potential drug candidates that can be useful for managing or treating neurodegenerative disease such as Alzheimer's disease, subject to further investigation.

Identification of potential inhibitors of cholinergic and β-secretase enzymes from phytochemicals derived from Gongronema latifolium Benth leaf: an integrated computational analysis.

Neurodegenerative disorders (NDDs) are associated with increased activities of the brain acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and β-secretase enzyme (BACE1). Inhibition of these enzymes affords therapeutic option for managing NDDs such as Alzheimer's disease (AD) and Parkinson's disease (PD). Although, Gongronema latifolium Benth (GL) has been widely documented in ethnopharmacological and scientific reports for the management of NDDs, there is paucity of information on its underlying mechanism and neurotherapeutic constituents. Herein, 152 previously reported Gongronema latifolium derived-phytochemicals (GLDP) were screened against hAChE, hBChE and hBACE-1 using molecular docking, molecular dynamics (MD) simulations, free energy of binding calculations and cluster analysis. The result of the computational analysis identified silymarin, alpha-amyrin and teraxeron with the highest binding energies (-12.3, -11.2, -10.5 Kcal/mol) for hAChE, hBChE and hBACE-1 respectively as compared with those of the reference inhibitors (-12.3, -9.8 and - 9.4 for donepezil, propidium and aminoquinoline compound respectively). These best docked phytochemicals were found to be orientated in the hydrophobic gorge where they interacted with the choline-binding pocket in the A-site and P-site of the cholinesterase and subsites S1, S3, S3' and flip (67-75) residues of the pocket of the BACE-1. The best docked phytochemicals complexed with the target proteins were stable in a 100 ns molecular dynamic simulation. The interactions with the catalytic residues were preserved during the simulation as observed from the MMGBSA decomposition and cluster analyses. The presence of these phytocompounds most notably silymarin, which demonstrated dual high binding tendencies to both cholinesterases, were identified as potential neurotherapeutics subject to further investigation.

Molecular Multi-Target Approach for Human Acetylcholinesterase, Butyrylcholinesterase and β-Secretase 1: Next Generation for Alzheimer's Disease Treatment.

Alzheimer's Disease (AD) is a neurodegenerative condition characterized by progressive memory loss and other affected cognitive functions. Pharmacological therapy of AD relies on inhibitors of the enzymes acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), offering only a palliative effect and being incapable of stopping or reversing the neurodegenerative process. However, recent studies have shown that inhibiting the enzyme β-secretase 1 (BACE-1) may be able to stop neurodegeneration, making it a promising target. Considering these three enzymatic targets, it becomes feasible to apply computational techniques to guide the identification and planning of molecules capable of binding to all of them. After virtually screening 2119 molecules from a library, 13 hybrids were built and further screened by triple pharmacophoric model, molecular docking, and molecular dynamics (t = 200 ns). The selected hybrid G meets all stereo-electronic requirements to bind to AChE, BChE, and BACE-1 and offers a promising structure for future synthesis, enzymatic testing, and validation.

Potential drugs for the treatment of Alzheimer's disease.

It is well known that amyloid precursor protein (APP), the enzyme β-secretase 1 (BACE1), cyclooxygenase 2 (COX-2), nicastrin (NCT), and hyperphosphorylated tau protein (p-tau) are closely related to the development of Alzheimer's disease (AD). In addition, recent evidence shows that neuroinflammation also contributes to the pathogenesis of AD. Although the mechanism is not clearly known, such inflammation could alter the activity of the aforementioned molecules. Therefore, the use of anti-inflammatory agents could slow the progression of the disease. Nimesulide, resveratrol, and citalopram are three anti-inflammatory agents that could contribute to a decrease in neuroinflammation and consequently to a decrease in the overexpression of APP, BACE1, COX-2, NCT, and p-Tau, as they possess anti-inflammatory effects that could regulate the expression of APP, BACE1, COX-2, NCT, and p-Tau of potent pro-inflammatory markers indirectly involved in the expression of APP, BACE1, NCT, COX-2, and p-Tau; therefore, their use could be beneficial as preventive treatment as well as in the early stages of AD.

Isolation, Structural Elucidation, In Vitro Anti-α-Glucosidase, Anti-β-Secretase, and In Silico Studies of Bioactive Compound Isolated from Syzygium cumini L.

Diabetes is one of the main health issues worldwide because of its lifetime duration. To overcome this health problem, the current study was conducted. This investigation aims to explore the α-glucosidase and β-secretase potential of extract/fractions and pure isolated compounds of Syzygium cumini bark. The chloroform extract of Syzygium cumini bark was subjected to chromatographic analysis to yield compound 1. The structure of isolated phytochemical (1) was conducted using advanced spectroscopic analysis. Among test extracts, the chloroform fraction exhibited a significant effect against α-glucosidase with a % activity of 86.20% and an IC50 of 77.09 µM, while the isolated compound exhibited a promising effect with a % activity of 91.54 and an IC50 value of 17.54 μM. The extract/fractions and isolated compound 1 also showed promising effects against the β-secretase enzyme, having % effects of 83.21 and 91.54% with IC50 values of 318.76 and 17.54 μM, respectively. The extract/fractions and compound 1 were found to possess promising inhibitory activity against α-glucosidase and β-secretase. This research project opens a new avenue for research into detailed chemical and biological studies on Syzygium cumini to isolate bioactive enzyme inhibitors. Furthermore, the isolated compound 1 friedelin was docked into the active site of β-secretase and α-glucosidase. The molecular docking was assessed using molecular docking via the MOE-Dock tool. The docking results showed good docking scores of −6.84 and −6.46 when docked against β-secretase and α-glucosidase, respectively, and strong interactions.

Evaluation of Mollugo oppositifolia Linn. as cholinesterase and β-secretase enzymes inhibitor.

Mollugo oppositifolia Linn. is traditionally used in neurological complications. The study aimed to investigate in-vitro neuroprotective effect of the plant extracts through testing against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and β-secretase linked to Alzheimer's disease (AD). To understand the safety aspects, the extracts were tested for CYP450 isozymes and human hepatocellular carcinoma cell (HepG2) inhibitory potential. The heavy metal contents were estimated using atomic absorption spectroscopy (AAS). Further, the antioxidant capacities as well as total phenolic content and total flavonoid content (TFC) were measured spectrophotometrically. UPLC-QTOF-MS/MS analysis was employed to identify phytometabolites present in the extract. The interactions of the ligands with the target proteins (AChE, BChE, and BACE-1) were studied using AutoDockTools 1.5.6. The results showed that M. oppositifolia extract has more selectivity towards BChE (IC50 = 278.23 ± 1.89μg/ml) as compared to AChE (IC50 = 322.87 ± 2.05μg/ml). The IC50 value against β-secretase was 173.93μg/ml. The extract showed a CC50 value of 965.45 ± 3.07μg/ml against HepG2 cells and the AAS analysis showed traces of lead 0.02 ± 0.001 which was found to be within the WHO prescribed limits. Moreover, the IC50 values against CYP3A4 (477.03 ± 2.01μg/ml) and CYP2D6 (249.65 ± 2.46μg/ml) isozymes justify the safety aspects of the extract. The in silico molecular docking analysis of the target enzymes showed that the compound menthoside was found to be the most stable and showed a good docking score among all the identified metabolites. Keeping in mind the multi-targeted drug approach, the present findings suggested that M. oppositifolia extract have anti-Alzheimer's potential.

Molecular Modeling Study of Methylxanthines and Tannins as Β-Secretase Inhibitors

Background: Alzheimer’s disease (AD) has been characterized by a progressive loss of cognitive functions, especially memory, impacting the daily life and personality of the elderly. In the present study, we performed molecular modeling of methylxanthines and tannins, with pharmacologic actions as stimulants of the Central Nervous System (CNS) and antioxidant, respectively, present in Paullinia cupana Kunth (guarana), evaluating the theoretical viability of these molecules as an alternative for the treatment of Alzheimer's disease, specifically to act by inhibiting the β-secretase enzyme (BACE-1). Methods: It has been accomplished a optimization of selected chemical structures, derivation of the pharmacophore, docking simulation, as well as prediction of physicochemical, pharmacokinetic (ADME) and toxicological (TOX) properties, ending with the activity prediction and synthetic viability of the selected molecules. For the physicochemical properties, evaluated according the Lipinski’s Rule of Five, only methylxanthines, catechin and epicatechin remained within the parameters evaluated. Results: In the molecular docking, caffeine, theobromine, theophylline, catechin, epicatechin, and proanthocyanidin, respectively, interacted with 57.14%, 42.86%, 28.57%, 57.14%, 28.57% e 57.14% of the active site amino acid residues of BACE-1. The ADME properties indicated the average permeability of the blood-brain barrier to the molecules caffeine, theobromine, theophylline, catechin and epicatechin, and caffeine, theobromine and theophylline showed high intestinal absorption and low aggregation to plasma proteins. The TOX properties showed only proanthocyanidin as a safer molecule. Only catechin and epicatechin were related to the action of BACE-1 in predicting activity. The synthetic viability of methylxanthine has been evaluated as high, while catechin and epicatechin were median and proanthocyanidin has been evaluated as difficult. Conclusion: catechin and epicatechin tannins presented more favorable results indicating interaction of suppression of the Aβ aggregation, being potential BACE-1 inhibitors.

Cathepsin B-A Neuronal Death Mediator in Alzheimer's Disease Leading to Neurodegeneration.

The lysosomal cysteine protease enzyme, named Cathepsin B, mainly degrades the protein and manages its average turnover in our body. The Cathepsin B active form is mostly present inside the lysosomal part at a cellular level, providing the slightly acidic medium for its activation. Multiple findings on Cathepsin B reveal its involvement in neurons' degeneration and a possible role as a neuronal death mediator in several neurodegenerative diseases. In this review article, we highlight the participation of Cathepsin B in the etiology/progress of AD, along with various other factors. The enzyme is involved in producing neurotoxic Aβ amyloid in the AD brain by acting as the β-secretase enzyme in the regulated secretory pathways responsible for APP processing. Aβ amyloid accumulation and amyloid plaque formation lead to neuronal degeneration, one of the prominent pathological hallmarks of AD. Cathepsin B is also involved in the production of PGlu-Aβ, which is a truncated and highly neurotoxic form of Aβ. Some of the findings also revealed that Cathepsin B specific gene deletion decreases the level of PGlu-Aβ inside the brain of experimental mice. Therefore, neurotoxicity might be considered a new pathological indication of AD due to the involvement of Cathepsin B. It also damages neurons present in the CNS region by producing inflammatory responses and generating mitochondrial ROS. However, Cathepsin B inhibitors, i.e., CA-074, can prevent neuronal death in AD patients. The other natural inhibitors are also equally effective against neuronal damage with higher selectivity. Its synthetic inhibitors are specific for their target; however, they lose their selectivity in the presence of quite a few reducing agents. Therefore, a humanized monoclonal antibody is used as a selective Cathepsin B inhibitor to overcome the problem experienced. The use of Cathepsin B for the treatment of AD and other neurodegenerative diseases could be considered a rational therapeutic target.

P-Coumaric acid protects against D-galactose induced neurotoxicity by attenuating neuroinflammation and apoptosis in mice brain.

D-galactose (D-gal) induced senescence in rodents is a widely used model for assessment of molecules affecting brain ageing. Chronic administration of D-gal causes neuroinflammation leading to cognitive deficit and memory impairment which represent Alzheimer's dementia. In present study, we investigated the neuroprotective effects of the natural phenol, p-Coumaric acid (PCA) and its underlying mechanism in the chronic D-gal treated mice. Subcutaneous administration of D-gal (150mg/kg) to Swiss albino mice for 42 consecutive days resulted in cognitive impairment as observed in Morris water maize (MWM) and Y maze test, which was ameliorated by concurrent treatment with PCA (80mg/kg, and 100mg/kg, p.o.). Importantly, PCA treatment attenuated the D-gal induced oxidative stress and significantly inhibited acetylcholinesterase (AChE) activity in mice brain. Furthermore, PCA treatment significantly lowered levels of inflammatory marker nuclear factor kappa B (NFκB) and reduced levels of proapoptotic enzyme caspase3. We also observed that PCA treatment exhibited β-secretase enzyme (BACE1) inhibitory effect. However, our results revealed that PCA treatment failed to decrease the level of advanced glycation end products both in vitro and in vivo. Taken together, current study demonstrated the significant neuroprotective effect of PCA against D-gal induced oxidative stress, neuroinflammation, cognitive impairment and apoptosis.

Friedelin Attenuates Neuronal Dysfunction and Memory Impairment by Inhibition of the Activated JNK/NF-κB Signalling Pathway in Scopolamine-Induced Mice Model of Neurodegeneration.

Oxidative stress (OS) and c-Jun N-terminal kinase (JNK) are both key indicators implicated in neuro-inflammatory signalling pathways and their respective neurodegenerative diseases. Drugs targeting these factors can be considered as suitable candidates for treatment of neuronal dysfunction and memory impairment. The present study encompasses beneficial effects of a naturally occurring triterpenoid, friedelin, against scopolamine-induced oxidative stress and neurodegenerative pathologies in mice models. The treated animals were subjected to behavioural tests i.e., Y-maze and Morris water maze (MWM) for memory dysfunction. The underlying mechanism was determined via western blotting, antioxidant enzymes and lipid profile analyses. Molecular docking studies were carried out to predict the binding modes of friedelin in the binding pocket of p-JNK protein. The results reveal that scopolamine caused oxidative stress by (1) inhibiting catalase (CAT), peroxidase enzyme (POD), superoxide dismutase (SOD), and reduced glutathione enzyme (GSH); (2) the up-regulation of thiobarbituric acid reactive substances (TBARS) in mice brain; and (3) affecting the neuronal synapse (both pre- and post-synapse) followed by associated memory dysfunction. In contrast, friedelin administration not only abolished scopolamine-induced oxidative stress, glial cell activation, and neuro-inflammation but also inhibited p-JNK and NF-κB and their downstream signaling molecules. Moreover, friedelin administration improved neuronal synapse and reversed scopolamine-induced memory impairment accompanied by the inhibition of β-secretase enzyme (BACE-1) to halt amyloidogenic pathways of amyloid-β production. In summary, all of the results show that friedelin is a potent naturally isolated neuro-therapeutic agent to reverse scopolamine-induced neuropathology, which is characteristic of Alzheimer’s disease.

Structure-Activity Relationship Analysis of Flavonoids and Its Inhibitory Activity Against BACE1 Enzyme Toward a Better Therapy for Alzheimer's Disease.

Drug development in Alzheimer’s disease (AD) suffers from a high attrition rate. In 2021, 117 agents tested in phases I and II and 36 agents tested in phase III were discontinued. Natural product compounds may be good lead compounds for AD as they contain functional groups that are important for binding against key AD targets such as β-secretase enzyme (BACE1). Hence, in this study, 64 flavonoids collected from rigorous literature search and screening that have been tested from 2010 to 2022 against BACE1, which interferes in the formation of amyloid plaque, were analyzed. The 64 unique flavonoids can be further classified into five core fragments. The flavonoids were subjected to clustering analysis based on its structure, and each representative of the clusters was subjected to molecular docking. There were 12 clusters formed, where only 1 cluster contained compounds from two different core fragments. Several observations can be made where 1) flavanones with sugar moieties showed higher inhibitory activity compared to flavanones without sugar moieties. The number of sugar moieties and position of glycosidic linkage may also affect the inhibitory activity. 2) Non-piperazine-substituted chalcones when substituted with functional groups with decreasing electronegativity at the para position of both rings result in a decrease in inhibitory activity. Molecular docking indicates that ring A is involved in hydrogen bond, whereas ring B is involved in van der Waals interaction with BACE1. 3) Hydrogen bond is an important interaction with the catalytic sites of BACE1, which are Asp32 and Asp228. As flavonoids contain favorable structures and properties, this makes them an interesting lead compound for BACE1. However, to date, no flavonoids have made it through clinical trials. Hence, these findings may aid in the design of highly potent and specific BACE1 inhibitors, which could delay the progression of AD.

Molecular docking and molecular dynamics approach to identify potential compounds in Huperzia squarrosa for treating Alzheimer's disease.

Alzheimer's disease (AD) is a lingering progressive neurodegenerative disorder that causes patients to lose cognitive function. The enzyme Acetylcholinesterase (AChE), Butyrylcholinesterase (BuChE), Monoamine oxidase A (MAO A), Beta-secretase cleavage enzyme (BACE 1) and N-methyl-D-aspartate (NMDA) receptors play an important role in the pathogenesis of Alzheimer's disease. Therefore, inhibiting enzymes is an effective method to treat Alzheimer disease. In this study, we evaluated in silico inhibitory effects of AChE, BuChE, MAO A, BACE 1 and NMDA enzyme of Huperzia squarrosa's compounds. The three-dimensional (3D) of N-methyl-D-aspartate receptor (PDB ID: 1PBQ), enzyme β-secretase 1 (PDB ID: 4X7I), enzyme monoamine oxidase A (PDB ID: 2Z5X), enzyme butyrylcholinesterase (PDB ID: 4BDS) and enzyme acetylcholinesterase (PDB ID: 1EVE) were retrieved from the Protein Data Bank RCSB. Molecular docking was done by Autodock vina software and molecular dynamics (MD) simulation of the ligand-protein complex with the least binding energy pose was perfomed by MOE. Lipinski Rule ofFive is used to compare compounds with drug-like and non-drug-like properties. Pharmacokinetic parameters of potential compounds were evaluated using the pkCSM tool. Based on previous publication of Huperzia squarrosa, we have collected 15 compounds. In these compounds, huperzine B, huperzinine, lycoposerramine U N-oxide, 12-epilycodine N-oxide showed strongly inhibit the five AChE, BuChE, MAO A, BACE 1 and NMDA targets for Alzheimer's treatment. Lipinski rule of five and ADMET predict have shown that four above compounds have drug-likeness properties, good absorption ability and cross the blood-brain barrier, which have the most potential to become drugs for the treatment of Alzheimer's in the future. Furthermore, MD study showed that huperzine B and huperzinine have stability of the docking pose with NMDA target. In this study, we found two natural compounds in Huperzia squarrosa including Huperzine B and Huperzinine have drug-likeness properties, good absorption ability and cross the blood-brain barrier, which have potential to become drugs for the treatment of Alzheimer's in the future.

Electrochemical Detection of Alzheimer's Disease Biomarker, β-Secretase Enzyme (BACE1), With One-Step Synthesized Reduced Graphene Oxide.

β-Secretase1 (BACE1) catalyzes the rate-limiting step in the generation of amyloid-β peptides, that is, the principal component involved in the pathology of Alzheimer’s disease (AD). Recent research studies show correlation between blood and cerebrospinal fluid (CSF) levels of BACE1 with the pathophysiology of AD. In this study, we report one-step synthesized reduced graphene oxide (rGO), activated via carbodiimide chemistry, conjugated with BACE1 antibody (Ab), and immobilized on fluorine-doped tin oxide (FTO) electrodes for rapid detection of BACE1 antigen (Ag) for AD diagnosis. The synthesis and fabrication steps were characterized using different types of spectroscopic, X-ray analytic, microscopic, and voltametric techniques. Various parameters including nanomaterial/Ab concentration, response time, pH, temperature, and rate of scan were standardized for maximum current output using the modified electrode. Final validation was performed via detection of BACE1 Ag ranging from 1 fM to 1 µM, with a detection limit of 0.64 fM in buffer samples and 1 fM in spiked serum samples, as well as negligible cross-reactivity with neurofilament Ag in buffer, spiked serum, and spiked artificial CSF. The proposed immunosensor gave a quick result in 30 s, and good repeatability and storage stability for a month, making it a promising candidate for sensitive, specific, and early diagnosis of AD. Thus, the fabricated electrochemical biosensor for BACE-1 detection improves detection performance compared to existing sensors as well as reduces detection time and cost, signifying its potential in early diagnosis of AD in clinical samples.

Cannabis Sativa L. Flower and Bud Extracts Inhibited In vitro Cholinesterases and β-Secretase Enzymes Activities: Possible Mechanisms of Cannabis Use in Alzheimer Disease.

There are anecdotal claims on the use of Cannabis sativa L. in the treatment of Alzheimer's disease, but there is a lack of scientific data to support the efficacy and safety of Cannabis sativa L. for Alzheimer's disease. The aim of the study was to evaluate the effect of aerial parts of Cannabis sativa L. on the cholinesterases and β-secretase enzymes activities as one of the possible mechanisms of Alzheimer's disease. The phytochemical and heavy metal contents were analysed. The extracts were screened for acetylcholinesterase, butyrylcholinesterase and β-secretase activity. Cytotoxicity of extracts was performed in normal vero and pre-adipocytes cell lines. The extracts were characterized using high-performance thin layer chromatography and high-performance liquid chromatography for their chemical fingerprints. Alkaloids, flavonoids and glycosides were present amongst the tested phytochemicals. Cannabidiol concentrations were comparatively high in the hexane and dichloromethane than in dichloromethane: methanol (1:1) and methanol extracts. Hexane and dichloromethane extracts showed a better inhibitory potential towards cholinesterase activity, while water, hexane, dichloromethane: methanol (1:1) and methanol showed an inhibitory potential towards β-secretase enzyme activity. All extracts showed no cytotoxic effect on pre-adipocytes and vero cells after 24- and 48-hours of exposure. Therefore, this may explain the mechanism through which AD symptoms may be treated and managed by Cannabis sativa L. extracts.