Assessment of antioxidant, acetylcholinesterase, paraoxonase inhibition activities and phenolic content of Alchemilla lithophila.

In the present study, antioxidant activity and inhibition of acetylcholinesterase (AChE) and paraoxonase (hPON 1) of Alchemilla lithophila extracts were evaluated for the first time. Besides, there is no research on the contents of phenolic compounds except for fatty acids. In this context, phenolic compounds of A. lithophila were investigated by liquid chromatography/ mass spectrometry (LC-MS/MS). The methanol extract of the A. lithophila exhibited significant inhibition on the AChE (IC50 value for methanol extract 0.162 ± 0.25 mg /mL, R2:0.992). Besides, antioxidant activities of the A. lithophila extracts were examined using by the methods ABTS•+ and DPPH• free radical scavenging potentials, FRAP and CUPRAC metal-reducing activities. ABTS•+ and DPPH• scavenging activities were found for methanol extract at 70.67% and water extract at 75.38%, respectively. Also, FRAP and CUPRAC metal-reducing were determined for water extract 0.796 and hexane extract 1.570 as absorbance. According to LC-MS/MS analyses, the amounts of ellagic acid, catechin hydrate, gallic acid, fumaric acid, luteolin, quercetin, kaempferol, acetohydroxamic acid, caffeic acid, syringic acid, hydroxybenzoic acid and salicylic acid were determined by LC-MS/MS, respectively. As a consequence, this study will be a useful resource for determining bioactivity and phenolic compound profile for natural medicine research.

Lycopodium alkaloids from Huperzia serrata and their cholinesterase inhibitory activities.

Huperzia serrata, belonging to the Lycopodiaceae family, has been traditionally utilized for the management of treating rheumatic numbness, arthritic pain, dysmenorrhea, and contusions. This plant is a rich source of lycopodium alkaloids, some of which have demonstrated notable cholinesterase inhibitory activity. The objective of this study was to identify lycopodium alkaloids with cholinesterase inhibitory properties from H. serrata. The structures of these alkaloids were elucidated by HRESIMS, NMR (including a 1H-15N HMBC experiment), ECD methods and single-crystal X-ray diffraction. The inhibitory activities against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) were assessed using a modified Ellman's method. Consequently, sixteen lycopodium alkaloids (1-16), including ten previously undescribed ones named huperradines A-G and huperradines I-K (1-7 and 9-11), along with one previously undescribed naturally occurring compound, huperradine H (8), were isolated from H. serrata. Among these, compounds 7 and 1 exhibited potent and moderate AChE inhibition, with IC50 values of 0.876 ± 0.039 µM and 13.125 ± 0.521 µM, respectively. Our results suggest that huperradine G (7) may be a promising lead compound for the development of new AChE inhibitors for Alzheimer's disease.

4-Amidophenol Quinone Methide Precursors: Effective and Broad-Scope Nonoxime Reactivators of Organophosphorus-Inhibited Cholinesterases and Resurrectors of Organophosphorus-Aged Acetylcholinesterase.

Acetylcholinesterase (AChE) inhibition by organophosphorus (OP) compounds poses a serious health risk to humans. While many therapeutics have been tested for treatment after OP exposure, there is still a need for efficient reactivation against all kinds of OP compounds, and current oxime therapeutics have poor blood-brain barrier penetration into the central nervous system, while offering no recovery in activity from the OP-aged forms of AChE. Herein, we report a novel library of 4-amidophenol quinone methide precursors (QMP) that provide effective reactivation against multiple OP-inhibited forms of AChE in addition to resurrecting the aged form of AChE after exposure to a pesticide or some phosphoramidates. Furthermore, these QMP compounds also reactivate OP-inhibited butyrylcholinesterase (BChE) which is an in vivo, endogenous scavenger of OP compounds. The in vitro efficacies of these QMP compounds were tested for reactivation and resurrection of soluble forms of human AChE and BChE and for reactivation of cholinesterases within human blood as well as blood and brain samples from a humanized mouse model. We identify compound 10c as a lead candidate due to its broad-scope efficacy against multiple OP compounds as well as both cholinesterases. With methylphosphonates, compound 10c (250 µM, 1 h) shows >60% recovered activity from OEt-inhibited AChE in human blood as well as mouse blood and brain, thus highlighting its potential for future in vivo analysis. For 10c, the effective concentration (EC50) is less than 25 µM for reactivation of three different methylphosphonate-inhibited forms of AChE, with a maximum reactivation yield above 80%. Similarly, for OP-inhibited BChE, 10c has EC50 values that are less than 150 µM for two different methylphosphonate compounds. Furthermore, an in vitro kinetic analysis show that 10c has a 2.2- and 92.1-fold superior reactivation efficiency against OEt-inhibited and OiBu-inhibited AChE, respectively, when compared to an oxime control. In addition to 10c being a potent reactivator of AChE and BChE, we also show that 10c is capable of resurrecting (ethyl paraoxon)-aged AChE, which is another current limitation of oximes.

Evaluation of GSTP1, GSTA4 and AChE Gene Methylation in Bovine Lymphocytes Cultured In Vitro with Miconazole Alone and in Combination with Mospilan 20SP.

5-methylcytosine (5mC) is one of the most important epigenetic modifications. Its increased occurrence in regulatory sequences of genes, such as promoters and enhancers, is associated with the inhibition of their expression. Methylation patterns are not stable but are sensitive to factors such as the environment, diet, and age. In the present study, we investigated the effects of fungicide miconazole, both alone and in combination with the insecticide Mospilan 20SP, on the methylation status of bovine GSTP1, GSTA4, and AChE genes in bovine lymphocytes cultured in vitro. The methylation-specific PCR technique was used for the objectives of this study. We found that miconazole alone at concentrations of 1.25, 2.5, 5, 10, 25, and 50 µg/mL after 24 h exposure probably did not induce changes in methylation for all three genes analysed. The same results were found for the combination of pesticides at 24 h exposure and the following concentrations for each of them: 0.625, 1.25, 2.5, 5, and 12.5 µg/mL. Thus, we can conclude that the fungicide miconazole alone, as well as in combination with the insecticide Mospilan 20SP, was unlikely to cause changes to the methylation of bovine GSTP1, GSTA4, and AChE genes.

Hesperidin methylchalcone (HMC) hinders amyloid-ß induced Alzheimer's disease by attenuating cholinesterase activity, macromolecular damages, oxidative stress and apoptosis via regulating NF-κB and Nrf2/HO-1 pathways.

Phytocompounds therapy has recently emerged as an effective strategy to treat Alzheimer's disease. Herein, the protective effect of hesperidin methylchalcone (HMC) was evaluated through Alzheimer's disease models of Neuro-2a cells and Wistar rats. The in vitro results showed that HMC possesses significant ability to inhibit the acetylcholinesterase enzyme and exhibiting anti-aggregation and disaggregation properties. Furthermore, HMC could protect the Neuro-2a cells against Aß-induced neurotoxicity. Simultaneously, HMC treatment significantly improved the cognitive deficits caused by Aß-peptide on spatial memory in Wistar rats. HMC significantly enhanced the cholinergic effects by inhibiting AChE, BuChE, ß-secretase activity, caspase-3 activity, and attenuating macromolecular damages and apoptosis. Notably, HMC reduced the Aß-induced oxidative stress by activating the antioxidative defence enzymes. In addition, the HMC treatment suppressed the expression of immunocytokines such as p-NF-κB p65, p-IκBα, induced by Aß; whereas upregulating Nrf2, HO-1 in brain homogenate. These results suggest that HMC could attenuate Aß-induced neuroinflammation in brain via suppressing NF-κB signalling pathway and activating the Nrf2/HO-1 pathway, thereby improving memory and cognitive impairments in Wistar rats. Overall, the present study reports that HMC can act as a potent candidate with multi-faceted neuroprotective potential against Aß-induced memory dysfunction in Wistar rats for the treatment of Alzheimer's disease.

Organophosphate pesticide exposure among farm women and children: Status of micronutrients, acetylcholinesterase activity, and oxidative stress.

Nutritional status plays a major role in determining the possible adverse health outcomes due to pesticide toxicity. The objective of the present study was to assess the organophosphorus pesticide residue levels among farm women (FW) (24-45years) and farm children (FC) (9-12 and 13-15years) belonging to the Rangareddy district (Telangana, India) along with their micronutrient status, inhibition of acetylcholinesterase activity, and oxidative stress levels. Residues of Chlorpyrifos, Diazinon, Malathion, Monocrotophos and Phosalone were found in the serum samples of FW and FC along with significantly low levels of vitamins and minerals. Inhibition of AChE activity was observed in FW and FC and altered oxidative stress parameters among FW. Correlation studies have found significant associations between the pesticide residues, micronutrients and antioxidant enzymes. The study suggests an association between pesticide exposure coupled with micronutrient deficiency, induced AChE inhibition, and oxidative stress.

Acute and long-term effects of VX in rat brain cell aggregate culture.

The contact poison VX (O-ethyl S-(2-diisopropylaminoethyl) methylphosphonothioate) is a chemical warfare agent that is one of the most toxic organophosphorus compounds known. Its primary mechanism of toxic action is through the inhibition of acetylcholinesterase and resultant respiratory paralysis. The majority of work on VX has thus concentrated on its potent anticholinesterase activity and acute toxicity, with few studies investigating potential long-term effects. In this report we describe the effects of VX in aggregating rat brain cell cultures out to 28 days post-exposure. Cholinesterase activity was rapidly inhibited (60 min IC50 = 0.73 +/- 0.27 nM), but recovered towards baseline values over the next four weeks. Apoptotic cell death, as measured using caspase-3 activity was evident only at 100 µM concentrations. Cell type specific enzymatic markers (glutamine synthase, choline acetyltransferase and 2',3'-cyclic nucleotide 3'-phosphodiesterase) showed no significant changes. Total Akt levels were unchanged, while an increased phosphorylation of this protein was noted only at the highest VX concentration on the first day post-exposure. In contrast, significant and delayed (28 days post-exposure) decreases were noted in vascular endothelial growth factor (VEGF) levels, a protein whose reduced levels are known to contribute to neurodegenerative disorders. These observations may indicate that the long-term effects noted in some survivors of nerve agent intoxication may be due to VX-induced declines in brain VEGF levels.

New insights into inhibitory nature of triclosan on acetylcholinesterase activity.

The antimicrobial agent, triclosan, has been designated as a "contaminant of emerging concern (CEC)". Previous in vivo studies have shown that triclosan exposure can inhibit acetylcholinesterase (AChE) activity. However, mechanistic insights into AChE inhibition by triclosan are missing. Here, using in vitro activity assay with purified AChE, we show that triclosan can directly inhibit AChE. In vivo, triclosan exposure resulted in reduced total antioxidant capacity concomitant with reduced AChE activity in the adult zebrafish brain. Adult zebrafish when pre-treated with antioxidant melatonin, resulted in attenuated oxidative stress and attenuated inhibitory effect of triclosan on the AChE activity. Our results indicate that triclosan can affect AChE activity both by direct binding and indirectly through increased oxidative stress and therefore, provide important mechanistic insights into triclosan induced neurotoxicity.

Cyclic Peptides from the Soft Coral-Derived Fungus Aspergillus sclerotiorum SCSIO 41031.

Three novel cyclic hexapeptides, sclerotides C-E (1-3), and a new lipodepsipeptide, scopularide I (4), together with a known cyclic hexapeptide sclerotide A (5), were isolated from fermented rice cultures of a soft coral-derived fungus: Aspergillus sclerotiorum SCSIO 41031. The structures of the new peptides were determined by 1D and 2D NMR spectroscopic analysis, Marfey's method, ESIMS/MS analysis, and single crystal X-ray diffraction analysis. Scopularide I (4) exhibited acetylcholinesterase inhibitory activity with an IC50 value of 15.6 µM, and weak cytotoxicity against the human nasopharyngeal carcinoma cell line HONE-EBV with IC50 value of 10.1 µM.

Synthesis and Evaluation of the Acetylcholinesterase Inhibitory Activities of Some Flavonoids Derived from Naringenin.

Alzheimer's disease (AD) is an irreversible neurodegenerative disease that affects many older people adversely. AD has been putting a huge socioeconomic burden on the healthcare systems of many developed countries with aging populations. The need for new therapies that can halt or reverse the progression of the disease is now extremely great. A research approach in the finding new treatment for AD that has attracted much interest from scientists for a long time is the reestablishment of cholinergic transmission through inhibition of acetylcholinesterase (AChE). Naringenin is a flavonoid with the potential inhibitory activity against AChE. From naringenin, many other flavonoid derivatives, such as flavanones and chalcones, can be synthesized. In this study, by applying the Williamson method, nine flavonoid derivatives were synthesized, including four flavanones and five chalcones. The evaluation of AChE inhibitory activity by the Ellman method showed that there were four substances (2, 4, 5, and 7) with relatively good biological activities (IC50 < 100 µM), and these biological activities were better than that of naringenin. The molecular docking revealed that strong interactions with amino acid residue Ser200 of the catalytic triad and those of the peripheral region of the enzyme were crucial for strong effects against AChE. Compound 7 had the strongest AChE inhibitory activity (IC50 13.0 ± 1.9 µM). This substance could be used for further studies.

The Positive Modulation Effect of a 6-Week Consumption of an Anthocyanin-Rich Mulberry Milk on Working Memory, Cholinergic, and Monoaminergic Functions in Healthy Working-Age Adults.

Due to the increase of stress-related memory impairment accompanying with the COVID-19 pandemic and financial crisis, the prevention of cognitive decline induced by stress has gained much attention. Based on the evidence that an anthocyanin-rich mulberry milk demonstrated the cognitive enhancing effect, we hypothesized that it should be able to enhance memory in working-age volunteers who are exposed to working stress. This study is an open-label, two-arm randomized study. Both men and women volunteers at age between 18 and 60 years old were randomly assigned to consume the tested product either 1 or 2 servings daily for 6 weeks. All subjects were assessed for cortisol, acetylcholinesterase (AChE), monoamine oxidase (MAO), monoamine oxidase type A (MAO-A), and monoamine oxidase type B (MAO-B) in saliva, and their working memory was determined both at baseline and at a 6-week period. The results showed that the working memory of subjects in both groups was enhanced at the end of the study period together with the reduction of saliva cortisol. The suppression of AChE, MAO, and MAO-A was also observed in subjects who consumed the tested product 2 servings daily. Therefore, we suggest the memory enhancing effect of an anthocyanin-rich mulberry milk. The possible mechanism may occur primarily via the suppression of cortisol. In addition, the high dose of mulberry milk also suppresses AChE, MAO, and MAO-A.

Anthraquinones, Diphenyl Ethers, and Their Derivatives from the Culture of the Marine Sponge-Associated Fungus Neosartorya spinosa KUFA 1047.

Previously unreported anthraquinone, acetylpenipurdin A (4), biphenyl ether, neospinosic acid (6), dibenzodioxepinone, and spinolactone (7) were isolated, together with (R)-6-hydroxymellein (1), penipurdin A (2), acetylquestinol (3), tenellic acid C (5), and vermixocin A (8) from the culture of a marine sponge-associated fungus Neosartorya spinosa KUFA1047. The structures of the previously unreported compounds were established based on an extensive analysis of 1D and 2D NMR spectra as well as HRMS data. The absolute configurations of the stereogenic centers of 5 and 7 were established unambiguously by comparing their calculated and experimental electronic circular dichroism (ECD) spectra. Compounds 2 and 5-8 were tested for their in vitro acetylcholinesterase and tyrosinase inhibitory activities as well as their antibacterial activity against Gram-positive and Gram-negative reference, and multidrug-resistant strains isolated from the environment. The tested compounds were also evaluated for their capacity to inhibit biofilm formation in the reference strains.

Covalent inhibition of hAChE by organophosphates causes homodimer dissociation through long-range allosteric effects.

Acetylcholinesterase (EC 3.1.1.7), a key acetylcholine-hydrolyzing enzyme in cholinergic neurotransmission, is present in a variety of states in situ, including monomers, C-terminally disulfide-linked homodimers, homotetramers, and up to three tetramers covalently attached to structural subunits. Could oligomerization that ensures high local concentrations of catalytic sites necessary for efficient neurotransmission be affected by environmental factors? Using small-angle X-ray scattering (SAXS) and cryo-EM, we demonstrate that homodimerization of recombinant monomeric human acetylcholinesterase (hAChE) in solution occurs through a C-terminal four-helix bundle at micromolar concentrations. We show that diethylphosphorylation of the active serine in the catalytic gorge or isopropylmethylphosphonylation by the RP enantiomer of sarin promotes a 10-fold increase in homodimer dissociation. We also demonstrate the dissociation of organophosphate (OP)-conjugated dimers is reversed by structurally diverse oximes 2PAM, HI6, or RS194B, as demonstrated by SAXS of diethylphosphoryl-hAChE. However, binding of oximes to the native ligand-free hAChE, binding of high-affinity reversible ligands, or formation of an SP-sarin-hAChE conjugate had no effect on homodimerization. Dissociation monitored by time-resolved SAXS occurs in milliseconds, consistent with rates of hAChE covalent inhibition. OP-induced dissociation was not observed in the SAXS profiles of the double-mutant Y337A/F338A, where the active center gorge volume is larger than in wildtype hAChE. These observations suggest a key role of the tightly packed acyl pocket in allosterically triggered OP-induced dimer dissociation, with the potential for local reduction of acetylcholine-hydrolytic power in situ. Computational models predict allosteric correlated motions extending from the acyl pocket toward the four-helix bundle dimerization interface 25 Å away.

Prospective Application of Two New Pyridine-Based Zinc (II) Amide Carboxylate in Management of Alzheimer's Disease: Synthesis, Characterization, Computational and in vitro Approaches.

BACKGROUND: Alzheimer's disease (AD) is a neurodegenerative illness described predominantly by dementia. Even though Alzheimer's disease has been known for over a century, its origin remains a mystery, and researchers are exploring many therapy options, including the cholinesterase technique. A decreased acetylcholine ACh neurotransmitter level is believed to be among the important factors in the progression of Alzheimer's disease. METHODS: In continuation of synthesizing potential anti-Alzheimer agents and known appreciative pharmacological potential of amide-containing compounds, this study presents the synthesis of two novel amide-based transition metal zinc (II) complexes, AAZ7 and AAZ8, attached with a heterocyclic pyridine ring, which was synthesized and characterized by Fourier transform infrared spectroscopy (FT-IR), elemental analysis, 1H_NMR, and 13C_NMR. FT-IR spectroscopic records showed the development of bidentate ligand as Δν value was decreased in both complexes when compared with the free ligand. Both of the synthesized complexes were analyzed for acetylcholinesterase and butyrylcholinesterase inhibitory potential along with the antioxidizing activity. RESULTS: Importantly, the complex of AAZ8 exhibited more potent activity giving IC50 values of 14 µg/mL and 18µg/mL as AChE and BChE cholinesterase inhibitors, respectively, when compared with standard positive control galantamine. Interestingly, AAZ8 also displayed promising antioxidant potential by showing IC50 values of 35 µg/mL for DPPH and 29 µg/mL for ABTS in comparison with positive control ascorbic acid. CONCLUSION: Herein, we report two new amide carboxylate zinc (II) complexes which were potentially analyzed for various biological applications like acetylcholinesterase (AChE), butyrylcholinesterase (BChE) inhibitory potentials, and antioxidant assays. Computational docking studies also simulated results to understand the interactions. Additionally, thermodynamic parameters utilizing molecular dynamic simulation were performed to determine the ligand protein stability and flexibility that supported the results. Studies have shown that these compounds have the potential to be good anti-Alzheimer candidates for future studies due to inhibition of cholinesterase enzymes and display of free radical scavenging potential against DPPH as well as ABTS free radicals.

Green Roccella phycopsis Ach. mediated silver nanoparticles: synthesis, characterization, phenolic content, antioxidant, antibacterial and anti-acetylcholinesterase capacities.

In this study, we develop here for the first time an easy, eco-friendly method for synthesizing silver nanoparticles (AgNPs) using the lichen Roccella phycopsis. AgNPs formation was first determined by a color change of the lichen filtrate to brown, subsequent to addition of AgNO3 solution, and confirmed by a maximum absorbance peak at 425 nm in UV-vis spectrum. Scanning electron microscope images showed a spherical shape with a size distribution between 11 and 18 nm, while the elemental composition was elucidated by the energy dispersive X-ray spectroscopy. The chemical compounds responsible for reduction and stabilization of silver nanoparticles were detected by Frourier transform infrared spectroscopy analysis. The synthesized R. phycopsis silver nanoparticles displayed a strong antioxidant activity. Further, the antibacterial activity was more effective against Gram-negative than Gram-positive bacteria. Besides, the R. phycopsis-AgNPs were potent in inhibiting acetylcholinesterase enzyme with IC50 value of 1.65 ± 0.07 mg/mL.

Design, synthesis, in silico studies and in vitro evaluation of isatin-pyridine oximes hybrids as novel acetylcholinesterase reactivators.

Organophosphorus poisoning caused by some pesticides and nerve agents is a life-threating condition that must be swiftly addressed to avoid casualties. Despite the availability of medical countermeasures, the clinically available compounds lack a broad spectrum, are not effective towards all organophosphorus toxins, and have poor pharmacokinetics properties to allow them crossing the blood-brain barrier, hampering cholinesterase reactivation at the central nervous system. In this work, we designed and synthesised novel isatin derivatives, linked to a pyridinium 4-oxime moiety by an alkyl chain with improved calculated properties, and tested their reactivation potency against paraoxon- and NEMP-inhibited acetylcholinesterase in comparison to the standard antidote pralidoxime. Our results showed that these compounds displayed comparable in vitro reactivation also pointed by the in silico studies, suggesting that they are promising compounds to tackle organophosphorus poisoning.

Synthesis and biological evaluation of some 1-naphthol derivatives as antioxidants, acetylcholinesterase, and carbonic anhydrase inhibitors.

A series of some naphthol derivatives 4a-f, 5a,f, 6a, and 7a,b (six novel ones: 4c,d, 5a, 6a, 7a,b) bearing F, Cl, Br, OMe, and dioxole substituents at different positions of the aromatic rings was designed, synthesized, and characterized. The naphthol derivatives were synthesized in three steps, namely the addition reaction of furan via Diels-Alder cycloaddition reaction, copper(II) trifluoromethanesulfonate (Cu(OTf)2 )-catalyzed aromatization reaction, and the bromination reaction, respectively. The structures of the newly obtained compounds (4c,d, 5a, 6a, 7a,b) were characterized by spectroscopic techniques. In addition, some biological activity studies were investigated under in vitro conditions. Inhibition studies of these compounds were performed on human carbonic anhydrase (hCA) I and II isoenzymes purified from human erythrocytes as a biological evaluation. Moreover, their potential antioxidant and antiradical activities were studied by analytical methods like ABTS•+ and DPPH• scavenging, and it was determined that some molecules showed good activity. Also, inhibition of acetylcholinesterase (AChE), which is a marker of many degenerative neurological diseases, was tested and the results were discussed. Excellent enzyme inhibition results were recorded for most of the molecules. These 1-naphthol derivatives were found as effective inhibitors for hCA I, hCA II, and AChE with K i values ranging from 0.034 ± 0.54 to 0.724 ± 0.18 µM for hCA I, 0.172 ± 0.02 to 0.562 ± 0.21 µM for hCA II, and 0.096 ± 0.01 to 0.177 ± 0.02 µM for AChE.

Does the application of acetylcholinesterase inhibitors in the treatment of Alzheimer's disease lead to depression?

Introduction: Alzheimer's disease and depression are health conditions affecting millions of people around the world. Both are strongly related to the level of the neurotransmitter acetylcholine. Since cholinergic deficit is characteristic of Alzheimer's disease, acetylcholinesterase inhibitors are applied as relevant drugs for the treatment of this disease, elevating the level of acetylcholine. On the other hand, a high level of acetylcholine is found to be associated with the symptoms of clinical depression.Areas covered: This article aims to discuss if acetylcholinesterase inhibitors used as anti-Alzheimer's drugs could be the cause of the symptoms of clinical depression often linked to this neurological disorder. Emphasis will be put on drugs currently in use and on newly investigated natural products, which can inhibit AChE activity.Expert opinion: Currently, it is not proven that the patient treated for Alzheimer's disease is prone to increased risk for depression due to the acetylcholinesterase inhibition, but there are strong indications. The level of acetylcholine is not the only factor in highly complicated diseases like AD and depression. Still, it needs to be considered isolated, keeping in mind the nature of presently available therapy, especially during a rational drug design process.

Hybridization-based design of novel anticholinesterase indanone-carbamates for Alzheimer's disease: Synthesis, biological evaluation, and docking studies.

Inspired by the structures of donepezil and rivastigmine, a novel series of indanone-carbamate hybrids was synthesized using the pharmacophore hybridization-based design strategy, and their biological activities toward acetylcholinesterase (AChE) and butyrylcholinesterase were evaluated. Among the synthesized compounds, 4d and 4b showed the highest AChE inhibitory activities with IC50 values in the micromolar range (compound 4d: IC50 = 3.04 µM; compound 4b: IC50 = 4.64 µM). Moreover, the results of the Aß1-40 aggregation assay revealed that compound 4b is a potent Aß1-40 aggregation inhibitor. The kinetics of AChE enzymatic activity in the presence of 4b was investigated, and the results were indicative of a reversible partial noncompetitive type of inhibition. A molecular docking study was conducted to determine the possible allosteric binding mode of 4b with the enzyme. The allosteric nature of AChE inhibition by these compounds provides the opportunity for the design of subtype-selective enzyme inhibitors. The presented indanone-carbamate scaffold can be structurally modified and optimized through medicinal chemistry-based approaches for designing novel multitargeted anti-Alzheimer agents.

Evaluation of antioxidant and inhibitory properties of Citrus aurantium L. on the acetylcholinesterase activity and the production of amyloid nano-bio fibrils.

The blossoms of Citrus aurantium are considered for the treatment of Alzheimer's disease because of their fragrant essential oils. The aim of this study was to investigate the antioxidant and inhibitory effects of Citrus aurantium extract on the acetylcholinesterase and production of amyloid nanobiofibrils from bovine serum albumin (BSA). The Citrus aurantium petals were harvested from Rasht city in northern IRAN. Chemical composition was investigated by GC-MS. The anti-Alzheimer's effects were evaluated by determining the antioxidant percentage by DPPH method and determining acetylcholinesterase activity. Congored spectroscopy was used for investigation of the inhibitory properties of the extract on the production of amyloid nanobiofibrils, and amyloid fibers was confirmed by electron microscopy. The most abundant ingredients were D-Glucuronic acid (9.53%), D-Limonene (5.54%), Linalool (2.06%), Daphnetin (3.73%), Phthalic acid (0.72%), Octadecenoic acid (3.98%), Hexadecanoic acid (2.13%), Pyrrolidinone (1.17%) and the highest antioxidant capacity was at 8 mg/ml (EC50: 2.36 mg/ml). The extract reduced the Acetylcholinesterase activity less than 47.04% (IC50: 42.8 mg/ml) and amyloid production less than 22% (EC50: 3.135). Citrus aurantium petals with inhibitory properties for the production of amyloid nanobiofibrils, can be used as a beneficial drugs for reducing side effects of Alzheimer's disease.