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Cyanobacteria, especially Arthrospira, are valuable resources of nutrients and natural pigments with many beneficial health-related properties. This study optimized the extraction conditions of Arthrospira to achieve high phenolic contents and antioxidant activities. Under optimized extraction conditions, the bioactive compounds (phenolics and pigment components), antioxidant activities, and inhibitions of the key enzymes relevant to some non-communicable diseases were compared between Arthrospira platensis and Arthrospira maxima. Optimized extraction conditions were determined as 2 h shaking time, 50 °C extraction temperature, and 1% (w/v) solid-to-liquid ratio, giving effective phenolic and phycocyanin contents using aqueous extraction, while 80% (v/v) aqueous ethanolic extraction provided high total chlorophyll content. Most antioxidant activities were higher using 80% (v/v) aqueous ethanolic extracts. Both Arthrospira species inhibited the key enzymes involved in controlling non-communicable diseases including hyperlipidemia (lipase), diabetes (α-amylase, α-glucosidase, and dipeptidyl peptidase-IV), Alzheimer's disease (acetylcholinesterase, butyrylcholinesterase and β-secretase), and hypertension (angiotensin-converting enzyme). High inhibitory activities were detected against β-secretase (BACE-1), the enzyme responsible for β-amyloid plaque formation in the brain that acts as a significant hallmark of Alzheimer's disease. Arthrospira extract and donepezil (Alzheimer's disease drug) synergistically inhibited BACE-1, suggesting the potential of Arthrospira extracts as effective BACE-1 inhibitors. Interestingly, A. maxima exhibited higher bioactive compound contents, antioxidant activities, and key enzyme inhibitions than A. platensis, indicating high potential for future food and medicinal applications. [ABSTRACT FROM AUTHOR]

The number of people with dementia is increasing annually worldwide. Alzheimer's disease (AD), which accounts for the highest percentage of dementia-causing diseases, remains difficult to cure, and prevention of its onset is important. We aimed to discover new AD-preventive ingredients and investigate the inhibitory effects of ten different species of seafood digests prepared by protease treatment on β-secretase 1 (BACE1) activity. Substantial inhibition of BACE1 activity was observed in five species of seafood, and protease-digested whitebait (WPD) showed the highest inhibitory effect among the ten marine samples. We further examined the potential of WPD as an AD preventive component using a familial AD strain (5xFAD) murine model. The intraperitoneal administration of WPD for 28 days substantially decreased the insoluble amyloid β1–42 content and the expression of glial fibrillary acidic protein, a marker of astrogliosis, in the cerebral cortex of the 5xFAD mice. These results strongly suggest that WPD is a novel functional food-derived ingredient with preventive effects against AD. [ABSTRACT FROM AUTHOR]

This study aimed to provide scientific data on the anti-Alzheimer's disease (AD) effects of phenolic compounds from Drynariae Rhizoma (DR) extract using a multi-component approach. Screening of DR extracts, fractions, and the ten phenolic compounds isolated from DR against the key AD-related enzymes acetylcholinesterase (AChE), butyrylcholinesterase (BChE), β-site amyloid precursor protein cleaving enzyme 1 (BACE1), and monoamine oxidase-B (MAO-B) confirmed their significant inhibitory activities. The DR extract was confirmed to have BACE1-inhibitory activity, and the ethyl acetate and butanol fractions were found to inhibit all AD-related enzymes, including BACE1, AChE, BChE, and MAO-B. Among the isolated phenolic compounds, compounds (2) caffeic acid 4-O-β-D-glucopyranoside, (6) kaempferol 3-O-rhamnoside 7-O-glucoside, (7) kaempferol 3-o-b-d-glucopyranoside-7-o-a-L-arabinofuranoside, (8) neoeriocitrin, (9) naringin, and (10) hesperidin significantly suppressed AD-related enzymes. Notably, compounds 2 and 8 reduced soluble Amyloid Precursor Protein β (sAPPβ) and β-secretase expression by over 45% at a concentration of 1.0 μM. In the thioflavin T assay, compounds 6 and 7 decreased Aβ aggregation by approximately 40% and 80%, respectively, and degraded preformed Aβ aggregates. This study provides robust evidence regarding the potential of DR as a natural therapeutic agent for AD, highlighting specific compounds that may contribute to its efficacy. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is a progressive neurodegenerative disorder marked by the accumulation of amyloid-beta plaques and hyperphosphorylated tau proteins, leading to cognitive decline and neuronal death. However, despite extensive research, there are still no effective treatments for this condition. In this study, a series of chloride-substituted Ramalin derivatives is synthesized to optimize their antioxidant, anti-inflammatory, and their potential to target key pathological features of Alzheimer's disease. The effect of the chloride position on these properties is investigated, specifically examining the potential of these derivatives to inhibit tau aggregation and beta-site amyloid precursor protein cleaving enzyme 1 (BACE-1) activity. Our findings demonstrate that several derivatives, particularly RA-3Cl, RA-4Cl, RA-26Cl, RA-34Cl, and RA-35Cl, significantly inhibit tau aggregation with inhibition rates of approximately 50%. For BACE-1 inhibition, Ramalin and RA-4Cl also significantly decrease BACE-1 expression in N2a cells by 40% and 38%, respectively, while RA-23Cl and RA-24Cl showed inhibition rates of 30% and 35% in SH-SY5Y cells. These results suggest that chloride-substituted Ramalin derivatives possess promising multifunctional properties for AD treatment, warranting further investigation and optimization for clinical applications. [ABSTRACT FROM AUTHOR]

Abstract Cyanobacteria, especially Arthrospira, are valuable resources of nutrients and natural pigments with many beneficial health-related properties. This study optimized the extraction conditions of Arthrospira to achieve high phenolic contents and antioxidant activities. Under optimized extraction conditions, the bioactive compounds (phenolics and pigment components), antioxidant activities, and inhibitions of the key enzymes relevant to some non-communicable diseases were compared between Arthrospira platensis and Arthrospira maxima. Optimized extraction conditions were determined as 2 h shaking time, 50 °C extraction temperature, and 1% (w/v) solid-to-liquid ratio, giving effective phenolic and phycocyanin contents using aqueous extraction, while 80% (v/v) aqueous ethanolic extraction provided high total chlorophyll content. Most antioxidant activities were higher using 80% (v/v) aqueous ethanolic extracts. Both Arthrospira species inhibited the key enzymes involved in controlling non-communicable diseases including hyperlipidemia (lipase), diabetes (α-amylase, α-glucosidase, and dipeptidyl peptidase-IV), Alzheimer’s disease (acetylcholinesterase, butyrylcholinesterase and β-secretase), and hypertension (angiotensin-converting enzyme). High inhibitory activities were detected against β-secretase (BACE-1), the enzyme responsible for β-amyloid plaque formation in the brain that acts as a significant hallmark of Alzheimer’s disease. Arthrospira extract and donepezil (Alzheimer’s disease drug) synergistically inhibited BACE-1, suggesting the potential of Arthrospira extracts as effective BACE-1 inhibitors. Interestingly, A. maxima exhibited higher bioactive compound contents, antioxidant activities, and key enzyme inhibitions than A. platensis, indicating high potential for future food and medicinal applications.

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.

Argemone mexicana L. is a medicinal plant, but its impact on Alzheimer's disease (AD) is right now undetermined. We intended to investigate the in-vitro anti-AD potential of leaves and flowers of A. mexicana methanol, ethanol, and ethyl extracts and to identify multi-modal anti-AD phytochemicals by computational approaches. Molecular docking of 196 phytochemicals identified three hit phytochemicals (protoberberine, protopine, and codeine) with higher binding affinity and multi-targeting ability toward AChE, BChE, BACE-1, and GSK-3β. Further MM-GBSA assays confirmed the integrity of these phytochemicals as the hit phytochemicals. However, these phytochemicals demonstrated favorable pharmacokinetics (PK) and drugable properties having no toxicity. Molecular dynamics simulations confirmed the binding strength of the hit phytoconstituents in the active pockets of AChE, BChE, BACE-1, and GSK-3β with multi-targeting inhibitory activities. All the extracts exhibited dose-dependent antioxidant and anti-cholinesterase activities supporting the insilico results in the context of oxidative stress and cholinergic pathways. Our results offer scientific validation of the anti-AD properties of Argemone mexicana L. and identified protoberberine, protopine, and codeine that could be used for the development of multi-modal inhibitors of AChE, BChE, BACE-1, and GSK-3β to combat AD. Additional in vivo validation is recommended to ensure a thorough assessment in the present research.

Background: Alzheimer’s disease (AD) is the most common form of dementia and dementia constitutes the fifth leading cause of mortality across the globe. Available treatment modalities and drugs have abysmally failed to curtail AD. This study evaluated the mitigation of Aβ aggregation and anti-cholinesterase activities with the crude extracts of Ptaeroxylon obliquum and Bauhinia bowkeri. Computational studies of the most abundant phytochemicals from the crude extracts of both plants with proteins were investigated. The phytochemical composition of the different crude extracts (hexane, DCM, and ethanol) of the plants were analyzed with FTIR and GC-MS. The inhibitory potential of the extracts on BACE-1 and cholinesterase activities was determined with both computational molecular docking studies and in vitro enzyme assays. Their anti-aggregation properties were confirmed with Thioflavin-T assay and TEM. Results: The in silico studies revealed that though thunbergol and cyclotetradecatriene (the major constituents of the extracts) inhibited all the proteins, the latter exhibited the best inhibitory potential. The in vitro results showed that while the dichloromethane (DCM) extract of P. obliquum had the highest butyrylcholinesterase (BuChE) inhibitory activity (1.77 µg/ml), the hexane and ethanol extract of B. bowkeri exhibited the highest β-site amyloid precursor cleaving enzymes-1 (BACE-1) (30.4 µg/ml) and acetylcholinesterase (AChE) (58.11 µg/ml) inhibitory efficacy, respectively. The ethanol extract (160 μg/ml) of B. bowkeri had the most efficacious anti-aggregation activity. Conclusions: This study suggests that the plants could possess neuroprotective effects and could also be sources of anti-AD novel drugs.How to cite: Ojo MC, Mosa RA, Osunsanmi FO, et al. In silico and in vitro assessment of the anti-β-amyloid aggregation and anti-cholinesterase activities of Ptaeroxylon obliquum and Bauhinia bowkeri extracts. Electron J Biotechnol 2024;68. https://doi.org/10.1016/j.ejbt.2023.11.004.

Background: Understanding the phenomena underlying the non-selective susceptibility to ischemia of pyramidal neurons in the CA3 is important from the point of view of elucidating the mechanisms of memory loss and the development of dementia. Objective: The aim of the study was to investigate changes in genes expression of amyloid precursor protein, its cleaving enzymes and tau protein in CA3 post-ischemia with survival of 12–24 months. Methods: We used an ischemic model of Alzheimer's disease to study the above genes using an RT-PCR protocol. Results: The expression of the amyloid precursor protein gene was above the control values at all times post-ischemia. The expression of the α-secretase gene also exceeded the control values post-ischemia. The expression of the β-secretase gene increased 12 and 24 months post-ischemia, and 18 months was below control values. Presenilin 1 and 2 genes expression was significantly elevated at all times post-ischemia. Also, tau protein gene expression was significantly elevated throughout the observation period, and peak gene expression was present 12 months post-ischemia. Conclusions: The study suggests that the genes studied are involved in the non-amyloidogenic processing of amyloid precursor protein. Additionally data indicate that brain ischemia with long-term survival causes damage and death of pyramidal neurons in the CA3 area of the hippocampus in a modified tau protein-dependent manner. Thus defining a new and important mechanism of pyramidal neuronal death in the CA3 area post-ischemia. In addition expression of tau protein gene modification after brain ischemia is useful in identifying ischemic mechanisms occurring in Alzheimer's disease. [ABSTRACT FROM AUTHOR]

Alzheimer’s disease (AD) is the most common form of dementia and dementia constitutes the fifth leading cause of mortality across the globe. Available treatment modalities and drugs have abysmally failed to curtail AD. This study evaluated the mitigation of Aβ aggregation and anti-cholinesterase activities with the crude extracts of Ptaeroxylon obliquum and Bauhinia bowkeri. Computational studies of the most abundant phytochemicals from the crude extracts of both plants with proteins were investigated. The phytochemical composition of the different crude extracts (hexane, DCM, and ethanol) of the plants were analyzed with FTIR and GC-MS. The inhibitory potential of the extracts on BACE-1 and cholinesterase activities was determined with both computational molecular docking studies and in vitro enzyme assays. Their anti-aggregation properties were confirmed with Thioflavin-T assay and TEM. Results: The in silico studies revealed that though thunbergol and cyclotetradecatriene (the major constituents of the extracts) inhibited all the proteins, the latter exhibited the best inhibitory potential. The in vitro results showed that while the dichloromethane (DCM) extract of P. obliquum had the highest butyrylcholinesterase (BuChE) inhibitory activity (1.77 µg/ml), the hexane and ethanol extract of B. bowkeri exhibited the highest β-site amyloid precursor cleaving enzymes-1 (BACE-1) (30.4 µg/ml) and acetylcholinesterase (AChE) (58.11 µg/ml) inhibitory efficacy, respectively. The ethanol extract (160 µg/ml) of B. bowkeri had the most efficacious anti-aggregation activity. Conclusions: This study suggests that the plants could possess neuroprotective effects and could also be sources of anti-AD novel drugs. [ABSTRACT FROM AUTHOR]

Ginkgo biloba (GB) extracts have been used in clinical studies as an alternative therapy for Alzheimer’s disease (AD), but the exact bioaction mechanism has not yet been elucidated. In this work, an in silico study on GB metabolites was carried out using SwissTargetPrediction to determine the proteins associated with AD. The resulting proteins, AChE, MAO-A, MAO-B, β-secretase and γ-secretase, were studied by molecular docking, resulting in the finding that kaempferol, quercetin, and luteolin have multitarget potential against AD. These compounds also exhibit antioxidant activity towards reactive oxygen species (ROS), so antioxidant tests were performed on the extracts using the DPPH and ABTS techniques. The ethanol and ethyl acetate GB extracts showed an important inhibition percentage, higher than 80%, at a dose of 0.01 mg/mL. The effect of GB extracts on AD resulted in multitarget action through two pathways: firstly, inhibiting enzymes responsible for degrading neurotransmitters and forming amyloid plaques; secondly, decreasing ROS in the central nervous system (CNS), reducing its deterioration, and promoting the formation of amyloid plaques. The results of this work demonstrate the great potential of GB as a medicinal plant.

The number of people with dementia is increasing annually worldwide. Alzheimer’s disease (AD), which accounts for the highest percentage of dementia-causing diseases, remains difficult to cure, and prevention of its onset is important. We aimed to discover new AD-preventive ingredients and investigate the inhibitory effects of ten different species of seafood digests prepared by protease treatment on β-secretase 1 (BACE1) activity. Substantial inhibition of BACE1 activity was observed in five species of seafood, and protease-digested whitebait (WPD) showed the highest inhibitory effect among the ten marine samples. We further examined the potential of WPD as an AD preventive component using a familial AD strain (5xFAD) murine model. The intraperitoneal administration of WPD for 28 days substantially decreased the insoluble amyloid β1–42 content and the expression of glial fibrillary acidic protein, a marker of astrogliosis, in the cerebral cortex of the 5xFAD mice. These results strongly suggest that WPD is a novel functional food-derived ingredient with preventive effects against AD.

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder marked by the accumulation of amyloid-beta plaques and hyperphosphorylated tau proteins, leading to cognitive decline and neuronal death. However, despite extensive research, there are still no effective treatments for this condition. In this study, a series of chloride-substituted Ramalin derivatives is synthesized to optimize their antioxidant, anti-inflammatory, and their potential to target key pathological features of Alzheimer’s disease. The effect of the chloride position on these properties is investigated, specifically examining the potential of these derivatives to inhibit tau aggregation and beta-site amyloid precursor protein cleaving enzyme 1 (BACE-1) activity. Our findings demonstrate that several derivatives, particularly RA-3Cl, RA-4Cl, RA-26Cl, RA-34Cl, and RA-35Cl, significantly inhibit tau aggregation with inhibition rates of approximately 50%. For BACE-1 inhibition, Ramalin and RA-4Cl also significantly decrease BACE-1 expression in N2a cells by 40% and 38%, respectively, while RA-23Cl and RA-24Cl showed inhibition rates of 30% and 35% in SH-SY5Y cells. These results suggest that chloride-substituted Ramalin derivatives possess promising multifunctional properties for AD treatment, warranting further investigation and optimization for clinical applications.

Modification of eudesmane-type sesquiterpene lactones and their epoxy derivatives with tryptamines was carried out using the aza-Michael reaction. A series of conjugates was obtained and their inhibitory properties were assessed against the β-secretase activity, which limits the rate of β-amyloid peptide formation and is a promising target for the treatment of Alzheimer's disease. It was found that compounds containing a 5-methoxytryptamine moiety show the greatest activity, reducing protease activity by 65–95% at a concentration of 100 µM and with an IC50 in the range from 15 to 48 µM. This allows us to consider the studied compounds as potential therapeutic agents against Alzheimer's disease. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is the prime cause of 65–80% of dementia cases and is caused by plaque and tangle deposition in the brain neurons leading to brain cell degeneration. β-secretase (BACE-1) is a key enzyme responsible for depositing extracellular plaques made of β-amyloid protein. Therefore, efforts are being applied to develop novel BACE-1 enzyme inhibitors to halt plaque build-up. In our study, we analyzed some Elenbecestat analogues (a BACE-1 inhibitor currently in clinical trials) using a structure-based drug design and scaffold morphing approach to achieve a superior therapeutic profile, followed by in silico studies, including molecular docking and pharmacokinetics methodologies. Among all the designed compounds, SB306 and SB12 showed good interactions with the catalytic dyad motifs (Asp228 and Asp32) of the BACE-1 enzyme with drug-likeliness properties and a high degree of thermodynamic stability confirmed by the molecular dynamic and stability of the simulated system indicating the inhibitory nature of the SB306 and SB12 on BACE 1. [ABSTRACT FROM AUTHOR]

Resveratrol (RES), a natural polyphenolic phytochemical, has been suggested as a putative anti-aging molecule for the prevention and treatment of Alzheimer's disease (AD) by the activation of sirtuin 1 (Sirt1/Sir2). In this study, we tested the effects of RES and Sirt1/Sir2 on sleep and courtship memory in a Drosophila model by overexpression of amyloid precursor protein (APP), whose duplications and mutations cause familial AD. We found a mild but significant transcriptional increase of Drosophila Sir2 (dSir2) by RES supplementation for up to 17 days in APP flies, but not for 7 days. RES and dSir2 almost completely reversed the sleep and memory deficits in APP flies. We further demonstrated that dSir2 acts as a sleep promotor in Drosophila neurons. Interestingly, RES increased sleep in the absence of dSir2 in dSir2-null mutants, and RES further enhanced sleep when dSir2 was either overexpressed or knocked down in APP flies. Finally, we showed that Aβ aggregates in APP flies were reduced by RES and dSir2, probably via inhibiting Drosophila β-secretase (dBACE). Our data suggest that RES rescues the APP-induced behavioral deficits and Aβ burden largely, but not exclusively, via dSir2. [ABSTRACT FROM AUTHOR]

The lysosomal cysteine protease cathepsin B (CTSB) has been suggested as a biomarker for Alzheimer's disease (AD) because elevated serum CTSB in AD patients has been found to correlate with cognitive dysfunction. Furthermore, CTSB gene knockout (KO) in non-transgenic and transgenic AD animal models showed that elimination of CTSB improved memory deficits. However, conflicting CTSB KO results on amyloid-β (Aβ) pathology in transgenic AD models have been reported. The conflict is resolved here as likely being due to the different hAβPP transgenes used in the different AD mouse models. CTSB gene KO reduced wild-type (Wt) β-secretase activity, brain Aβ, pyroglutamate-Aβ, amyloid plaque, and memory deficits in models that used cDNA transgenes expressing hAβPP isoform 695. But in models that used mutated mini transgenes expressing hAβPP isoforms 751 and 770, CTSB KO had no effect on Wt β-secretase activity and slightly increased brain Aβ. All models expressed the AβPP transgenes in neurons. These conflicting results in Wt β-secretase activity models can be explained by hAβPP isoform specific cellular expression, proteolysis, and subcellular processing. CTSB KO had no effect on Swedish mutant (Swe) β-secretase activity in hAβPP695 and hAβPP751/770 models. Different proteolytic sensitivities for hAβPP with Wt versus Swe β-secretase site sequences may explain the different CTSB β-secretase effects in hAβPP695 models. But since the vast majority of sporadic AD patients have Wt β-secretase activity, the CTSB effects on Swe β-secretase activity are of little importance to the general AD population. As neurons naturally produce and process hAβPP isoform 695 and not the 751 and 770 isoforms, only the hAβPP695 Wt models mimic the natural neuronal hAβPP processing and Aβ production occurring in most AD patients. Significantly, these CTSB KO findings in the hAβPP695 Wt models demonstrate that CTSB participates in memory deficits and production of pyroglutamate-Aβ (pyroglu-Aβ), which provide rationale for future investigation of CTSB inhibitors in AD therapeutics development. [ABSTRACT FROM AUTHOR]

Background: β-site amyloid precursor protein cleaving enzyme 1 (BACE1) is a key enzyme in the formation of amyloid-β (Aβ) protein. Increasing evidence suggests that BACE1 concentration is a potential biomarker for Alzheimer's disease (AD). Objective: To evaluate the correlations between plasma BACE1 concentration, cognition, and hippocampal volume at different stages of the AD continuum. Methods: Plasma BACE1 concentrations were measured in 32 patients with probable dementia due to AD (ADD), 48 patients with mild cognitive impairment (MCI) due to AD, and 40 cognitively unimpaired (CU) individuals. Memory function was evaluated using the auditory verbal learning test (AVLT), and voxel-based morphometry was used to analyze bilateral hippocampal volumes. Correlation and mediation analyses were performed to investigate the associations between plasma BACE1 concentration, cognition, and hippocampal atrophy. Results: The MCI and ADD groups exhibited elevated BACE1 concentrations compared with the CU group after adjusting for age, sex, and apolipoprotein E (APOE) genotype. Increased BACE1 concentration was found in AD continuum patients who were APOE ɛ4 carriers (p < 0.05). BACE1 concentration was negatively associated with the scores of the subitems of the AVLT and hippocampal volume (p < 0.05, false discovery rate correction) in the MCI group. Moreover, bilateral hippocampal volume mediated the relationship between BACE1 concentration and recognition in the MCI group. Conclusion: BACE1 expression increased in the AD continuum, and bilateral hippocampal volume mediated the effect of BACE1 concentration on memory function in patients with MCI. Research has indicated that the plasma BACE1 concentration might be a biomarker at the early stage of AD. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract Background The deposition of β-amyloid (Aβ) in the brain plays a major role in the pathogenesis of Alzheimer’s disease (AD). Aβ is generated via amyloid precursor protein (APP) cleavage through the amyloidogenic pathway. In this pathway, β-secretase (BACE1) is the first and rate-limiting enzyme. Its expression increases through an unknown mechanism in patients with AD. Thus, the key regulatory mechanism of BACE1 in the AD process should be revealed to understand the pathogenesis of AD and explore the key treatment targets of AD. Methods Here, APPswe/PS1dE9 (APP/PS1) mice were employed to observe the Krüppel-like factor 5 (KLF5) and BACE1 levels in the serum and brain tissues. HT22 cells were used to explore the relationship between KLF5 and BACE1. Results In this study, KLF5 was found to be a novel transcription factor that positively regulated BACE1 by binding to the BACE1 promoter. The KLF5 levels significantly increased not only in the CSF and serum of patients with AD but also in the brain tissue of APP/PS1 mice. They were closely related to cognitive capacity. KLF5 accelerated APP amyloidogenic metabolism and promoted Aβ synthesis through BACE1. Silencing BACE1 could block the KLF5-induced amyloidogenic process of APP. ML264 ameliorated the cognitive deficits and slowed down APP amyloidogenic cleavage in APP/PS1 mice. Conclusion The findings above suggest that upregulation of KLF5 might be a critical element in AD progression by accelerating BACE1-mediated APP amyloidogenic cleavage. The inhibition of KLF5 or the combined inhibitory effect of KLF5 and the BACE1 promoter might be a potential strategy to prevent AD pathogenesis.

Cleavage of Amyloid precursor protein by β- and γ-secretases lead to Ab formation. The widely accepted pathogenic model states that these mutations cause AD via an increase in Ab formation and accumulation of Ab in Amyloid plaques. APP mutations cause early onset familial forms of Alzheimer's disease (FAD) in humans. We generated App-Swedish (Apps) knock-in rats, which carry a pathogenic APP mutation in the endogenous rat App gene. This mutation increases β-secretase processing of APP leading to both augmented Ab production and facilitation of glutamate release in Apps=s rats, via a β-secretase and APP-dependent glutamate release mechanism. Here, we studied 11 to 14-month-old male and female Apps=s rats. To determine whether the Swedish App mutation leads to behavioral deficits, Apps=s knock-in rats were subjected to behavioral analysis using the IntelliCage platform, an automated behavioral testing system. This system allows behavioral assessment in socially housed animals reflecting a more natural, less stress-inducing environment and eliminates experimenter error and bias while increasing precision of measurements. Surprisingly, a spatial discrimination and flexibility task that can reveal deficits in higher order brain function showed that Apps=s females, but not Apps=s male rats, performed significantly worse than same sex controls. Moreover, female control rats performed significantly better than control and Apps=s male rats. The Swedish mutation causes a significant increase in Ab production in 14-month-old animals of both sexes. Yet, male and female Apps=s rats showed no evidence of AD-related amyloid pathology. Finally, Apps=s rats did not show signs of significant neuroinflammation. Given that the APP Swedish mutation causes alterations in glutamate release, we analyzed Long-term potentiation (LTP), a long-lasting form of synaptic plasticity that is a cellular basis for learning and memory. Strikingly, LTP was significantly increased in Apps=s control females compared to both Apps=s sexes and control males. In conclusion, this study shows that behavioral performances are sex and App-genotype dependent. In addition, they are associated with LTP values and not Aβ or AD-related pathology. These data, and the failures of anti-Ab therapies in humans, suggest that alternative pathways, such as those leading to LTP dysfunction, should be targeted for disease-modifying AD therapy. [ABSTRACT FROM AUTHOR]

The rationale to define the biological and molecular parameters derived from structure–activity relationships (SAR) is mandatory for the lead selection of small drug compounds. Several series of small molecules have been synthesized based on a computer-assisted pharmacophore design derived from two series of compounds whose scaffold originates from chloroquine or amodiaquine. All compounds share similar biological activities. In vivo, Alzheimer's disease-related pathological lesions are reduced, consisting of amyloid deposition and neurofibrillary degeneration, which restore and reduce cognitive-associated impairments and neuroinflammation, respectively. Screening election was performed using a cell-based assay to measure the repression of Aβ1–x peptide production, the increased stability of APP metabolites, and modulation of the ratio of autophagy markers. These screening parameters enabled us to select compounds as potent non-competitive β-secretase modulators, associated with various levels of lysosomotropic or autophagy modulatory activities. Structure–activity relationship analyses enabled us to define that (1) selectively reducing the production of Aβ1–x, and (2) little Aβx–40/42 modification together with (3) a decreased ratio of p62/(LC3-I/LC3-II) enabled the selection of non-competitive β-secretase modulators. Increased stability of CTFα and AICD precluded the selection of compounds with lysosomotropic activity whereas cell toxicity was associated with the sole p62 enhanced expression shown to be driven by the loss of nitrogen moieties. These SAR parameters are herein proposed with thresholds that enable the selection of potent anti-Alzheimer drugs for which further investigation is necessary to determine the basic mechanism underlying their mode of action. [ABSTRACT FROM AUTHOR]

Alzheimer’s disease (AD) is the prime cause of 65–80% of dementia cases and is caused by plaque and tangle deposition in the brain neurons leading to brain cell degeneration. β-secretase (BACE-1) is a key enzyme responsible for depositing extracellular plaques made of β-amyloid protein. Therefore, efforts are being applied to develop novel BACE-1 enzyme inhibitors to halt plaque build-up. In our study, we analyzed some Elenbecestat analogues (a BACE-1 inhibitor currently in clinical trials) using a structure-based drug design and scaffold morphing approach to achieve a superior therapeutic profile, followed by in silico studies, including molecular docking and pharmacokinetics methodologies. Among all the designed compounds, SB306 and SB12 showed good interactions with the catalytic dyad motifs (Asp228 and Asp32) of the BACE-1 enzyme with drug-likeliness properties and a high degree of thermodynamic stability confirmed by the molecular dynamic and stability of the simulated system indicating the inhibitory nature of the SB306 and SB12 on BACE 1.

Cleavage of Amyloid precursor protein by β- and γ-secretases lead to Aβ formation. The widely accepted pathogenic model states that these mutations cause AD via an increase in Aβ formation and accumulation of Aβ in Amyloid plaques. APP mutations cause early onset familial forms of Alzheimer’s disease (FAD) in humans. We generated App−Swedish (Apps) knock−in rats, which carry a pathogenic APP mutation in the endogenous rat App gene. This mutation increases β-secretase processing of APP leading to both augmented Aβ production and facilitation of glutamate release in Apps/s rats, via a β-secretase and APP−dependent glutamate release mechanism. Here, we studied 11 to 14-month-old male and female Apps/s rats. To determine whether the Swedish App mutation leads to behavioral deficits, Apps/s knock-in rats were subjected to behavioral analysis using the IntelliCage platform, an automated behavioral testing system. This system allows behavioral assessment in socially housed animals reflecting a more natural, less stress-inducing environment and eliminates experimenter error and bias while increasing precision of measurements. Surprisingly, a spatial discrimination and flexibility task that can reveal deficits in higher order brain function showed that Apps/s females, but not Apps/s male rats, performed significantly worse than same sex controls. Moreover, female control rats performed significantly better than control and Apps/s male rats. The Swedish mutation causes a significant increase in Aβ production in 14-month-old animals of both sexes. Yet, male and female Apps/s rats showed no evidence of AD−related amyloid pathology. Finally, Apps/s rats did not show signs of significant neuroinflammation. Given that the APP Swedish mutation causes alterations in glutamate release, we analyzed Long-term potentiation (LTP), a long-lasting form of synaptic plasticity that is a cellular basis for learning and memory. Strikingly, LTP was significantly increased in Apps/s control females compared to both Apps/s sexes and control males. In conclusion, this study shows that behavioral performances are sex and App-genotype dependent. In addition, they are associated with LTP values and not Aβ or AD-related pathology. These data, and the failures of anti-Aβ therapies in humans, suggest that alternative pathways, such as those leading to LTP dysfunction, should be targeted for disease-modifying AD therapy.

Argemone mexicana L. is a medicinal plant, but its impact on Alzheimer's disease (AD) is right now undetermined. We intended to investigate the in-vitro anti-AD potential of leaves and flowers of A. mexicana methanol, ethanol, and ethyl extracts and to identify multi-modal anti-AD phytochemicals by computational approaches. Molecular docking of 196 phytochemicals identified three hit phytochemicals (protoberberine, protopine, and codeine) with higher binding affinity and multi-targeting ability toward AChE, BChE, BACE-1, and GSK-3β. Further MM-GBSA assays confirmed the integrity of these phytochemicals as the hit phytochemicals. However, these phytochemicals demonstrated favorable pharmacokinetics (PK) and drugable properties having no toxicity. Molecular dynamics simulations confirmed the binding strength of the hit phytoconstituents in the active pockets of AChE, BChE, BACE-1, and GSK-3β with multi-targeting inhibitory activities. All the extracts exhibited dose-dependent antioxidant and anti-cholinesterase activities supporting the in silico results in the context of oxidative stress and cholinergic pathways. Our results offer scientific validation of the anti-AD properties of Argemone mexicana L. and identified protoberberine, protopine, and codeine that could be used for the development of multi-modal inhibitors of AChE, BChE, BACE-1, and GSK-3β to combat AD. Additional in vivo validation is recommended to ensure a thorough assessment in the present research., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have influenced the work presented in this paper., (© 2024 Published by Elsevier Ltd.)

This study examines the synthesis and evaluation of 11 newly developed compounds as potential anti-Alzheimer's agents that occur via cholinesterase and β-secretase inhibition. The compounds were tested for their inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) using the modified Ellman method. The results showed that several compounds exhibited significant inhibition of AChE, particularly compounds 6d, 7a, and 7e, which demonstrated high inhibitory activity at lower concentrations, with IC 50 values of 0.120, 0.039, and 0.063 µM, respectively. However, the compounds showed limited effectiveness against BChE, with only a few compounds exhibiting moderate inhibition. Compound 7e showed an inhibitory effect against BACE-1 close to that of the standard drug. Structural analysis revealed that the compounds with substituted benzothiazole and thiazole moieties exhibited the most promising inhibitory activity. This study provides valuable insights into the potential of these synthesized derivatives as a treatment against Alzheimer's disease. Moreover, the structure, stability, and properties of the active compounds were further investigated using density functional theory calculations. As a final note, the utilization of molecular docking and molecular dynamics simulation studies allowed us to elucidate the action mechanism of the active compounds and gain insights into the structure-activity relationship against AChE and β-secretase proteins. These computational techniques provide valuable information on the binding modes, interactions with target enzymes, dynamic behavior, and conformational changes of the compounds, enabling a comprehensive understanding of their biological activity., (© 2024 Deutsche Pharmazeutische Gesellschaft.)

Background: The deposition of β-amyloid (Aβ) in the brain plays a major role in the pathogenesis of Alzheimer's disease (AD). Aβ is generated via amyloid precursor protein (APP) cleavage through the amyloidogenic pathway. In this pathway, β-secretase (BACE1) is the first and rate-limiting enzyme. Its expression increases through an unknown mechanism in patients with AD. Thus, the key regulatory mechanism of BACE1 in the AD process should be revealed to understand the pathogenesis of AD and explore the key treatment targets of AD. Methods: Here, APPswe/PS1dE9 (APP/PS1) mice were employed to observe the Krüppel-like factor 5 (KLF5) and BACE1 levels in the serum and brain tissues. HT22 cells were used to explore the relationship between KLF5 and BACE1. Results: In this study, KLF5 was found to be a novel transcription factor that positively regulated BACE1 by binding to the BACE1 promoter. The KLF5 levels significantly increased not only in the CSF and serum of patients with AD but also in the brain tissue of APP/PS1 mice. They were closely related to cognitive capacity. KLF5 accelerated APP amyloidogenic metabolism and promoted Aβ synthesis through BACE1. Silencing BACE1 could block the KLF5-induced amyloidogenic process of APP. ML264 ameliorated the cognitive deficits and slowed down APP amyloidogenic cleavage in APP/PS1 mice. Conclusion: The findings above suggest that upregulation of KLF5 might be a critical element in AD progression by accelerating BACE1-mediated APP amyloidogenic cleavage. The inhibition of KLF5 or the combined inhibitory effect of KLF5 and the BACE1 promoter might be a potential strategy to prevent AD pathogenesis. [ABSTRACT FROM AUTHOR]

In this study, the expression of the genes of the amyloid protein precursor, β-secretase, presenilin 1 and 2 by RT-PCR in the lymphocytes of newborns after perinatal asphyxia and perinatal asphyxia treated with hypothermia was analyzed at the age of 15–21 days. The relative quantification of Alzheimer's-disease-related genes was first performed by comparing the peripheral lymphocytes of non-asphyxia control versus those with asphyxia or asphyxia with hypothermia. In the newborns who had perinatal asphyxia, the peripheral lymphocytes presented a decreased expression of the amyloid protein precursor and β-secretase genes. On the other hand, the expression of the presenilin 1 and 2 genes increased in the studied group. The expression of the studied genes in the asphyxia group treated with hypothermia had an identical pattern of changes that were not statistically significant to the asphyxia group. This suggests that the expression of the genes involved in the metabolism of the amyloid protein precursor in the peripheral lymphocytes may be a biomarker of progressive pathological processes in the brain after asphyxia that are not affected by hypothermia. These are the first data in the world showing the role of hypothermia in the gene changes associated with Alzheimer's disease in the peripheral lymphocytes of newborns after asphyxia. [ABSTRACT FROM AUTHOR]

Amyloid precursor‐like protein‐2 (APLP2) and its C‐terminal fragments (CTFs) are expressed at high levels in pancreatic cancer cells and knockdown of APLP2 expression inhibits tumor growth. CTFs are released from APLP2 by beta‐secretase (BACE). In this study, our goal was to determine whether methylene blue (MethB) and toluidine blue O (TBO) could be used to slow down the growth and viability of pancreatic cancer cells (Hs 766T). We found that TBO and MethB decreased the growth and viability of Hs 766T cells in a dose‐ and time‐dependent manner compared to vehicle‐treated control, as demonstrated by MTT and trypan blue exclusion assays. Although TBO led to decreased expression of APLP2, MethB did not show any significant effect on APLP2. However, both MethB and TBO reduced BACE activity and the levels of APLP2 CTFs in Hs 766T cells. In conclusion, MethB and TBO may be valuable candidates for the treatment of pancreatic cancer by targeting APLP2 processing. [ABSTRACT FROM AUTHOR]

It is considered that brain ischemia can be causative connected to Alzheimer's disease. In the CA1 and CA3 regions of the hippocampus and temporal cortex, genes related to Alzheimer's disease, such as the amyloid protein precursor (APP), β-secretase (BACE1), presenilin 1 (PSEN1) and 2 (PSEN2), are deregulated by ischemia. The pattern of change in the CA1 area of the hippocampus covers all genes tested, and the changes occur at all post-ischemic times. In contrast, the pattern of gene changes in the CA3 subfield is much less intense, does not occur at all post-ischemic times, and is delayed in time post-ischemia relative to the CA1 field. Conversely, the pattern of gene alterations in the temporal cortex appears immediately after ischemia, and does not occur at all post-ischemic times and does not affect all genes. Evidence therefore suggests that various forms of dysregulation of the APP, BACE1 and PSEN1 and PSEN2 genes are associated with individual neuronal cell responses in the CA1 and CA3 areas of the hippocampus and temporal cortex with reversible cerebral ischemia. Scientific data indicate that an ischemic episode of the brain is a trigger of amyloidogenic processes. From the information provided, it appears that post-ischemic brain injury additionally activates neuronal death in the hippocampus and temporal cortex in an amyloid-dependent manner. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is a progressive neurological illness with few effective treatments. Thus, ameliorating the effects of AD using natural products has attracted global attention with promising efficacy and safety. In this study, ten tropical fruits including Ananas comosus 'Phulae', Ananas comosus 'Pattavia', Carica papaya 'Khaekdum', Carica papaya 'Khaeknuan', Durio zibethinus 'Monthong', Durio zibethinus 'Chanee', Psidium guajava 'Kimju', Psidium guajava 'Keenok', Mangifera indica 'Kaew' and Mangifera indica 'Namdokmai' were screened for their inhibitory activities against the key enzymes, cholinesterases and β-secretase (BACE-1), involved in AD pathogenesis. The top three fruit extracts with promising in vitro anti-AD activities were further investigated using rat pheochromocytoma PC-12 neuronal cell line and Drosophila AD model. Data showed that M. indica 'Kaew', M. indica 'Namdokmai' and P. guajava 'Kimju' reduced Aβ1–42-mediated neurotoxicity by promoting glutathione-dependent enzymes, while M. indica 'Namdokmai' limited Aβ1–42 peptide formation via BACE-1 inhibition and amended locomotory behavior of the Drosophila AD model. Results indicated the potential anti-AD properties of tropical fruits, particularly M. indica 'Namdokmai' in the prevention of Aβ1–42-mediated neurotoxicity and as a BACE-1 blocker. [ABSTRACT FROM AUTHOR]

Background: Alzheimer's disease amyloid-beta peptides (Aβ) are generated via sequential cleavage of the amyloid precursor protein (APP) by β-secretase (Bace1) and γ-secretase. Though the precise subcellular location(s) of Bace1-mediated APP cleavage remains unresolved, current models suggest APP internalization into Bace1-containing endosomes is a critical step. However, direct evidence for this model is lacking, and previous reports that probed the APP/Bace1 interaction (using co-expressed APP and Bace1 differentially labeled with fluorescent protein tags) did not determine if APP fluorescence originated from full-length APP (fl-APP) molecules that had internalized from the cell surface pool. Methods: We adapted the bungarotoxin-ligand (BTX) system to label surface APP and track internalized fluorescent APP/BTX puncta in rodent primary neurons co-expressing fluorescently-tagged Bace1. Subsequently, we employed imaging and biochemical-based approaches to measure N- and C-terminal APP epitope levels in primary neurons, N2a neuroblastoma, and HeLa cell lines. Results: We hypothesized that surface-labeled APP/BTX puncta would, upon internalization, colocalize with fluorescently-tagged Bace1. Unexpectedly, we observed a dramatic loss of internalized APP in co-transfected neurons and ~ 80–90% loss of surface-resident fl-APP, which we also observed in HeLa and N2a cells. Loss of surface fl-APP could be reversed by a Bace1 inhibitor, suggesting that enhanced Bace1-mediated APP cleavage was responsible for the altered processing and mis-sorting. Importantly, in a C-terminally-tagged APP construct, the majority of C-terminal fluorescence was preserved in HeLa cells despite the loss of N-terminal APP signal. This phenomenon was not only recapitulated in cultured neurons, but also showed a progressive disappearance of the APP N-terminal tag, reflecting continual cleavage of fl-APP by Bace1 away from the cell body. Conclusions: Our results strongly suggested that in APP/Bace1 co-expression approaches, there was significant early and aberrant Bace1-mediated APP cleavage that perturbed fl-APP trafficking from the secretory pathway onwards, resulting in a substantial loss of surface fl-APP, which in turn led to a marked reduction in APP internalization. In C-terminally-tagged APP constructs, a large fraction of the APP fluorescence signal therefore likely arose from fluorescently-tagged β-C-terminal-fragment (β-CTF) or downstream proteolytic derivatives instead of fl-APP. Thus, care is needed in interpreting results where APP is detected only with a C-terminal tag in the presence of Bace1 co-expression, and previous findings may need to be reinterpreted if it is unclear whether fl-APP is present in normal physiological levels. [ABSTRACT FROM AUTHOR]

The study aims to evaluate the neuroprotective properties of Pterocarpus marsupium Roxb. The bioactive optimized hydroalcohol-extracted fractions of bark (PMBHA) and heartwood (PMHHA) at 300 and 400 mg/kg were examined in rats with scopolamine-induced neurotoxicity to study oxidative, neurochemical, and neuroinflammation biomarkers. Phenol and flavonoid-rich radical scavengers in contributing total antioxidant capacities of PMBHA and PMHHA quenched peroxyl radicals and protected the cellular membrane and lipoproteins from ROS in DPPH, ORAC, and CAP-e tests. In anticholinesterase activities, PMBHA inhibited AChE (IC 50 : 54.40 ± 0.98 µg/mL) and BChE (IC 50 : 50.95 ± 0.98 µg/mL) mixed-competitively, while PMHHA inhibited cholinesterase activities (AChE: 42.23 ± 0.54, and BChE: 47.19 ± 0.65 µg/mL) competitively. Dosage at 300 and 400 mg/kg of PMBHA and PMHHA improved serum and brain oxidative indicators (MDA, SOD, CAT, and GSH), and restored proinflammatory cytokines (TNF-α, and IL-6) leading to enhanced brain cholinesterase and β-secretase levels in neurotoxic rats. GC-MS reported antioxidant, anti-inflammatory, and neuroprotective compounds of PMBHA catechol, thiamet-G, d-Gala-l-ido-octonic amide, falcarinol, D-mannose, ribitol, 1,2,4-cyclopentanetrione, 3-(2-pentenyl)-, hexadecanoic acid methyl ester, n-hexadecanoic acid, oleic acid, and 3,5-Dimethoxybenzyl alcohol, α-epi-7-epi-5-Eudesmol, 1 R,4aR,7 R,8aR)-7-(2-Hydroxypropan-2-yl)-1,4a-dimethyldecahydro naphthalen-1-ol, arctiol, 1,1,4,7-tetramethyldecahydro-1 H-cyclopropa[ e ]azulene-4,7-diol, 2-Propen-1-ol, 3-(2,6,6-trimethyl-1-cyclohexen-1-yl), 4-t-Butyl-2-[4-nitrophenyl]phenol in PMHHA were responsible in neuroprotection in neurotoxic rats. However, heartwood demonstrated better neuroprotective activities than the bark of P. marsupium due to some of the key compounds (1 R,4aR,7 R,8aR)-7-(2-Hydroxypropan-2-yl)-1,4a-dimethyldecahydronaphthalen-1-ol, 2-Propen-1-ol, 3-(2,6,6-trimethyl-1-cyclohexen-1-yl)-, 4-t-Butyl-2-[4-nitrophenyl]phenol, 1,1,4,7-Tetramethyldecahydro-1 H-cyclopropa[ e ]azulene-4,7-diol. [Display omitted] • Bark and heartwood of P. marsupium demonstrated neuroprotective activity. • Heartwood demonstrated better activities in DPPH, ORAC, and CAP-e tests. • Heartwood demonstrated better anticholinesterase activities. • Bark and heartwood of P. marsupium improved oxidative indicators in AD. • It restored inflammatory cytokines, β-secretase levels in neurotoxic rats. [ABSTRACT FROM AUTHOR]

Abstract Background Alzheimer’s disease (AD) is a progressive neurodegenerative age-related dementia that results in memory loss of elderly people. Many hypotheses have been formally articulated till now to decipher the pathogenesis of this disease. According to the compelling amyloidogenic hypothesis, β-secretase is a key regulatory enzyme in AD development and is therefore considered as one of the major targets for the development of drugs to treat AD. In this study, 40 plant-derived phytocompounds, proven to have β-secretase inhibitory activity in different laboratory experiments, were evaluated using computational approaches in order to identify the best possible β-secretase inhibitor(s). Results Amentoflavone (IFD score: − 7.842 Kcal/mol), Bilobetin (IFD score: − 7.417 Kcal/mol), and Ellagic acid (IFD score: − 6.923 Kcal/mol) showed highest β-secretase inhibitory activities with high binding affinity among all the selected phytocompounds and interacted with key amino acids, i.e., Asp32, Tyr71, and Asp228 in the catalytic site of β-secretase. Moreover, these three molecules exhibited promising results in different drug potential assessment experiments and displayed signs of correlation with significant pharmacological and biological activities. Conclusion Amentoflavone, Biolbetin, and Ellagic acid could be investigated further in developing β-secretase-dependent drug for the effective treatment of AD. However, additional in vivo and in vitro experiments might be required to strengthen the findings of this experiment.

Alzheimer's disease (AD) is a progressive neurodegenerative disease with the hallmark of aggregation of beta-amyloid (Aβ) into extracellular fibrillar deposition. Accumulating evidence suggests that soluble toxic Aβ oligomers exert diverse roles in neuronal cell death, oxidative stress, neuroinflammation, and the eventual pathogenesis of AD. Aβ is derived from the sequential cleavage of amyloid-β precursor protein (APP) by β-secretase (BACE1) and γ-secretase. The current effect of single targeting is not ideal for the treatment of AD. Therefore, developing multipotent agents with multiple properties, including anti-Aβ generation and anti-Aβ aggregation, is attracting more attention for AD treatment. Previous studies indicated that Quercetin was able to attenuate the effects of several pathogenetic factors in AD. Here, we showed that naturally synthesized Quercetin-3-O-glc-1-3-rham-1-6-glucoside (YCC31) could inhibit Aβ production by reducing β-secretase activity. Further investigations indicated that YCC31 could suppress toxic Aβ oligomer formation by directly binding to Aβ. Moreover, YCC31 could attenuate Aβ-mediated neuronal death, ROS and NO production, and pro-inflammatory cytokines release. Taken together, YCC31 targeting multiple pathogenetic factors deserves further investigation for drug development of AD. [Display omitted] [ABSTRACT FROM AUTHOR]

Alzheimer's disease is a life-threatening neurodegenerative disorder. About 50 million people across the globe are affected by this disease. At final stages, this disease causes patients to lose cognitive ability, memory, and brain cells to the point of being totally dependent on other individuals for livelihood. The incidence of this disease is increasing across the world in the recent years, making the need of a better drug an urgency. Existing drugs show various side effects and natural sources of medicinal drugs are being explored. In this study, we explore the activity of natural compounds isolated through GC–MS analysis from the haustoria of palmyra palm against two major Alzheimer's disease-causing enzymes, β-secretase and acetylcholinesterase. The binding affinity of these compounds against the target proteins and their pharmacokinetic properties were checked. Among the 37 compounds docked, 5 compounds showed good binding affinity and pharmacokinetic properties. These natural compounds showed a potential as a drug against Alzheimer's disease. Further research is needed to study the synergistic activity of the compounds in live cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • The bioactive peptides were separated from sea cucumber Holothuria spinifera. • Glycine was the most abundant amino acid in the dried H. spinifera. • Trypsin hydrolysate showed the highest β-secretase inhibitory activity. • The effect of active fraction (HPLC-F3) was tested in SH-SY5Y neuroblastoma cells. • HPLC-F3 reduced BACE, Aβ, sAPPβ, p-p38, and p-JNK protein expression levels. Alzheimer's disease (AD) is widely known as a progressive neurodegenerative disorder, mainly found in the elderly population. Progressive neurodegeneration in AD can lead to cognitive functional and behavioral alterations, thus affecting public health. Based on the amyloid cascade hypothesis, enzymatic cleavage of amyloid precursor protein (APP) by β-secretase and the formation of amyloid-beta (Aβ) peptides lead to neuron cell degradation. In this study, we focused on this hypothesis and investigated bioactivities of dried Holothuria spinifera enzymatic hydrolysates. Dried H. spinifera contained 79.77 % protein with glycine being the most abundant amino acid (178.89 g/kg). Trypsin hydrolysate of H. spinifera exhibited the highest β-secretase inhibitory activity with an IC 50 value of 81.94 μg/mL. RP-HPLC produced an active fraction (HPLC-F3) containing four bioactive peptides (YPIEHGIVTNWDDM*EK, IEELEEEIEAER, EYVEETTGDEYVSLK, YPIEHGIVTNWDDMEK). The predominant peptide presented in HPLC-F3 was IEELEEEIEAER. Effects of HPLC-F3 against SH-SY5Y neuroblastoma cells were tested. HPLC-F3 reduced cellular levels of β-secretase enzyme, Aβ, and soluble amyloid precursor protein beta (sAPPβ) proteins. HPLC-F3 also protected SH-SY5Y cells from oxidative stress by decreasing phosphorylation of c-Jun N-terminal kinases and p38 mitogen-activated protein kinases. Results of this study suggest that H. spinifera is a potential source for functional foods and biomedicine industries. [ABSTRACT FROM AUTHOR]

The beta‐site amyloid precursor protein cleaving enzyme 1 (BACE1) is a transmembrane aspartyl‐protease, that cleaves amyloid precursor protein (APP) at the β‐site. The sequential proteolytic cleavage of APP, first by β‐secretase and then by γ‐secretase complex, leads to the production and release of amyloid‐β peptide, a pathological hallmark of Alzheimer's disease (AD). BACE1 inhibitors are reported to possess considerable potential in decreasing the level of amyloid‐β in brain and preventing the progression of AD. A classification study has been conducted on 3536 diverse BACE1 inhibitors, obtained from Binding DB database, by extracting two types of descriptors, that is molecular property (Mordred) and fingerprints (Pubchem, MACCS and KRFP). Furthermore, based on the descriptors, various machine learning algorithms such as Naïve Bayesian (NB), nearest known neighbours (kNN), support vector machine (SVM), random forest (RF) and gradient‐boosted algorithms (XGB) were applied to develop classification models. The performance of models was evaluated by using accuracy, precision, recall and F1 score of test set. The best NB, kNN, SVM, RF and XGB classifiers had F1 score of 0.74, 0.85, 0.86, 0.87 and 0.87, respectively. The diverse 3536 BACE1 inhibitors were clustered into 11 subsets, and the structural features of each subset were evaluated. The important fragments present in active and inactive compounds were also identified. The model developed in the study would serve as a valuable tool for the designing of BACE1 inhibitors, and also in virtual screening of molecules to identify these. [ABSTRACT FROM AUTHOR]

• BACE1 expression is elevated in CD4+ T cells from AD patients and 5xFAD mice. • BACE1 regulates the activation of CD4+ T cells and promotes immune response. • BACE1 regulates TCR signalling by promoting mPGES2 maturation and PGE2 production. • Peripheral PGE2 signalling antagonists ameliorates the Aβ pathology in 5xFAD mice. Circulating CD4+ T cells are dysfunctional in Alzheimer's disease (AD), however, the underlying molecular mechanisms are not clear. In this study, we demonstrate that CD4+ T cells from AD patients and 5xFAD transgenic mice exhibit elevated levels of β-secretase 1 (BACE1). Overexpression of BACE1 in CD4+ T cells potentiated CD4+ T-cell activation and T-cell-dependent immune responses. Mechanistically, BACE1 modulates prostaglandin E2 (PGE2) synthetase—microsomal prostaglandin E synthase 2 (mPGES2)—to promote mPGES2 maturation and PGE2 production, which increases T-cell receptor (TCR) signalling. Moreover, administration of peripheral PGE2 signalling antagonists partially ameliorates CD4+ T cell overactivation and AD pathology in 5xFAD mice. Overall, our results reveal a potential role for BACE1 in mediating CD4+ T-cell dysfunction in AD. [ABSTRACT FROM AUTHOR]

Abstract Background Diabetes mellitus is a chronic disease characterized by hyperglycemia that may occur due to genetic, environmental or lifestyle factors. Natural remedies have been used to treat diabetes since long and many antidiabetic compounds of varied efficacies have been isolated from medicinal plants. Rhazya stricta has been used for decades for the treatment of diabetes mellitus and associated ailments. Considering the folkloric use of R. stricta against diabetes, it was aimed to investigate the effectiveness of its root extracts against diabetes through in vitro assays and in vivo studies using animal model along with phytochemical profiling through GCMS. Methods Various fractions of Rhazya stricta obtained through column chromatography were evaluated for a variety of assays including α-glucosidase, Dipeptidyl peptidase-IV (DPP-IV), β-secretase and Glucagon-like peptide-1 (GLP-1) secretion studies. For the in vivo studies the alloxan-induced diabetic mice were treated with root extracts and blood glucose levels, HbA1C, and other biochemical markers along with the histological study of the liver were done. The phytochemical identification was performed using an Agilent 7890B GC coupled to a 7010 Triple Quadrupole (MS/MS) system. GraphPad Prism software version 5.01 was used for statistical analysis. Results Majority of the extract fractions showed excellent results against diabetes by inhibiting enzymes DPP-IV (Up to 61%) and β-secretase (Up to 83%) with IC50s 979 μg/ml and 169 μg/ml respectively with increase in the GLP1 secretion. The results of in vivo studies indicated a marked reduction in blood glucose and HbA1c levels along with positive effects on other parameters like lipid profile, liver functions and renal functions of extract-treated mice as compared to control. The histological examination of the liver demonstrated hepatoprotective effects against diabetes led changes and various classes of phytochemicals were also identified through GCMS in different fractions. Conclusion The results revealed strong antidiabetic activity of R. stricta root with the potential to protect body organs against diabetic changes. Moreover, a variety of phytochemicals has also been identified through GCMS that might be responsible for the antidiabetic potential of Rhazya stricta root. Graphical abstract

Effective therapy of Alzheimer’s disease (AD) requires treatment with a combination of drugs that modulate various pathomechanisms contributing to the disease. In our research, we have focused on the development of multi-target-directed ligands – 5-HT6 receptor antagonists and cholinesterase inhibitors – with disease-modifying properties. We have performed extended in vitro (FRET assay) and in cellulo (Escherichia coli model of protein aggregation) studies on their β-secretase, tau, and amyloid β aggregation inhibitory activity. Within these multifunctional ligands, we have identified compound 17 with inhibitory potency against tau and amyloid β aggregation in in cellulo assay of 59% and 56% at 10 µM, respectively, hBACE IC50=4 µM, h5TH6 Ki=94 nM, hAChE IC50=26 nM, and eqBuChE IC50=5 nM. This study led to the development of multifunctional ligands with a broad range of biological activities crucial not only for the symptomatic but also for the disease-modifying treatment of AD.

Alzheimer's disease (AD) is a progressive multifaceted neurodegenerative disease and remains a formidable global health challenge. The current medication for AD gives symptomatic relief and, thus, urges us to look for alternative disease-modifying therapies based on a multitarget directed approach. Looking at the remarkable progress made in peptide drug development in the last decade and the benefits associated with peptides, they offer valuable chemotypes [multitarget directed ligands (MTDLs)] as AD therapeutics. This review recapitulates the current developments made in harnessing peptides as MTDLs in combating AD by targeting multiple key pathways involved in the disease's progression. The peptides hold immense potential and represent a convincing avenue in the pursuit of novel AD therapeutics. While hurdles remain, ongoing research offers hope that peptides may eventually provide a multifaceted approach to combat AD.

Alzheimer's disease (AD) is the main type of dementia found in the elderly population. The prevention of β-amyloid (Aβ) production by inhibiting β-secretase, which is required for Aβ generation, is the major focus of research in AD therapeutics. In this study, enzymatic extracts obtained from sea cucumber (Stichopus japonicus) hydrolysis were investigated for β-secretase inhibitory activities. Sea cucumber hydrolysates were prepared using various enzymes (Alcalase, α-chymotrypsin, Neutrase, papain, pepsin, and trypsin). Trypsin hydrolysate (IC50, 93.59 ± 0.68 μg/ml) with the highest β-secretase inhibitory activity was separated into crude polysaccharide (TCP) and protein (TP) by ethanol precipitation. TCP (IC50, 16.13 ± 1.15 μg/ml) exhibited higher β-secretase inhibitory activity than trypsin hydrolysate and TP (IC50, 563.50 ± 25.18 μg/ml). Total sugar content in TCP was 11.58 ± 0.32 g/100 g. Major monosaccharides present in S. japonicus were arabinose, fucose, galactose, mannose and ramnose at 1.76 mg/g, 11.98 mg/g, 1.33 mg/g and 0.1 mg/g, respectively. Sulfate and uronic acid contents were 5.69 ± 0.15 g/100 g and 0.49 ± 0.01 g/100 g. Cytotoxicity of TCP different concentrations were tested in SH-SY5Y cells using MTT assay. Treated concentrations at 1, 5, 10, 30, 50, and 100 µg/ml concentrations were not toxic at cellular level. Further, quantitative protein expression reduction of BACE, sAPPβ, β-amyloid, p-JNK, and p-p38 in SH-SY5Y cells were confirmed by Western blot analysis. Therefore, results of this study suggest the potential application of S. japonicus in food and biomedicine industries. [ABSTRACT FROM AUTHOR]

Excessive exposure to manganese (Mn) can cause cognitive impairment, a common feature of Alzheimer's disease (AD), but the mechanisms remain unclear. Amyloid precursor protein (APP) is key to AD pathogenesis, and whether APP and its secretase processing are involved in Mn-induced cognitive impairment remains unknown. In the present study, we established a model of Mn-induced neurotoxicity in vivo (male C57BL/6, 0–100 mg/kg Mn, 90 days, gastric gavage) and in vitro (Neuro-2a (N2a) cells, 0–800 μM Mn for 24 h; APP overexpression and APP shRNA N2a cells, 0 and 800 μM Mn for 24 h). We found impaired cognition of Mn-treated mice. Both in vivo and in vitro results consistently showed that Mn exposure inhibited the expression of APP, α-secretase, soluble APP alpha protein (sAPPα), and synapse proteins as well as the activity of α-secretase. However, Mn exposure showed no effect on the protein levels of β-secretase, Aβ40, and Aβ42 or the activity of β-secretase. Collectively, these findings demonstrate key roles of APP and its α-secretase processing in the regulation of Mn-induced cognitive impairment, which may act as a target for ameliorating Mn-induced neurotoxicity.

Intensive investigation of phytochemicals from edible Melicope glabra leaves provided a series of O-alkylated quercetins (1–13). The quercetin 1 bearing prenyl and methyl motif showed potent inhibition to human acetylcholinesterase (hAChE) with mixed type I mode, while quercetin was inactive. The position of methyl group was also a critical factor to hAChE inhibition: 1 (4′-O-methyl, IC50 = 12.7 μM) vs 2 (3′-O-methyl, IC50 = 119 μM). Inhibitory potency was doubly confirmed with the binding affinity (KSV) based on fluorescence quenching. O-Methyl groups on quercetin were observed to influence β-secretase (BACE1) inhibition. Thus, O-methylated quercetins (4–6) displayed potential inhibitions against BACE1 with IC50 values of 1.3, 4.1, and 14.1 μM, respectively. All compounds (3–6) have noncompetitive mode to BACE1. Additionally, all quercetin derivatives (1–13) had antioxidant potentials against different radical sources (ABTS, ORAC and FRAP). The UPLC-ESI-Q-TOF/MS indicated that the leaves part had promising metabolites towards hAChE and BACE1 inhibitions, which are the most predominant phytochemicals.

The rationale to define the biological and molecular parameters derived from structure–activity relationships (SAR) is mandatory for the lead selection of small drug compounds. Several series of small molecules have been synthesized based on a computer-assisted pharmacophore design derived from two series of compounds whose scaffold originates from chloroquine or amodiaquine. All compounds share similar biological activities. In vivo, Alzheimer’s disease-related pathological lesions are reduced, consisting of amyloid deposition and neurofibrillary degeneration, which restore and reduce cognitive-associated impairments and neuroinflammation, respectively. Screening election was performed using a cell-based assay to measure the repression of Aβ1–x peptide production, the increased stability of APP metabolites, and modulation of the ratio of autophagy markers. These screening parameters enabled us to select compounds as potent non-competitive β-secretase modulators, associated with various levels of lysosomotropic or autophagy modulatory activities. Structure–activity relationship analyses enabled us to define that (1) selectively reducing the production of Aβ1–x, and (2) little Aβx–40/42 modification together with (3) a decreased ratio of p62/(LC3-I/LC3-II) enabled the selection of non-competitive β-secretase modulators. Increased stability of CTFα and AICD precluded the selection of compounds with lysosomotropic activity whereas cell toxicity was associated with the sole p62 enhanced expression shown to be driven by the loss of nitrogen moieties. These SAR parameters are herein proposed with thresholds that enable the selection of potent anti-Alzheimer drugs for which further investigation is necessary to determine the basic mechanism underlying their mode of action.