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.

Synthesis of novel sulfonamides with anti-Alzheimer and antioxidant capacities.

A series of novel dopamine analogs incorporating urea and sulfonamide functional groups was synthesized from 3,4-dimethoxyphenethylamine. The reaction of 3,4-dimethoxyphenethylamine with N,N-dimethylcarbamoyl chloride, followed by the sulfonyl chlorination of the urea derivative, gave benzene-1-sulfonyl chloride 9, which was reacted with NH3 (aq) or N-alkyl amines to give related sulfonamides. The O-demethylation reaction of the subsequent compounds with BBr3 afforded four novel phenolic dopamine analogs including sulfonamide and urea in the same structure. The anticholinergic and antioxidant effects of the synthesized compounds were examined. Compound 13 exhibited inhibition at the micromolar level for both acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). The IC50 value of 13 was calculated as 298 ± 43 µM for AChE and 321 ± 29 µM for BChE. The antioxidant and antiradical effects of the molecules were investigated by five different methods. Among the synthesized compounds 10-18, the best antioxidant and antiradical activities belong to the phenolic compounds 15-18. Compounds 16 and 18 have a higher reducing power than the standards used, that is, butylated hydroxytoluene, butylated hydroxyanisole, Trolox, and α-tocopherol, for Fe3+ -Fe2+ and Cu2+ -Cu+ reducing activities. For the DPPH• radical scavenging method, compounds 16-18 have a much better scavenging power than the standard molecules. In addition, it has been determined by the induced-fit docking method that compound 13 is well-fitted in the active site of the enzymes. ADME studies reveal that the pharmacokinetic and physicochemical properties of all synthesized compounds are within an acceptable range.

In silico studies, nitric oxide, and cholinesterases inhibition activities of pyrazole and pyrazoline analogs of diarylpentanoids.

A new series of pyrazole, phenylpyrazole, and pyrazoline analogs of diarylpentanoids (excluding compounds 3a, 4a, 5a, and 5b) was pan-assay interference compounds-filtered and synthesized via the reaction of diarylpentanoids with hydrazine monohydrate and phenylhydrazine. Each analog was evaluated for its anti-inflammatory ability via the suppression of nitric oxide (NO) on IFN-γ/LPS-activated RAW264.7 macrophage cells. The compounds were also investigated for their inhibitory capability toward acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), using a modification of Ellman's spectrophotometric method. The most potent NO inhibitor was found to be phenylpyrazole analog 4c, followed by 4e, when compared with curcumin. In contrast, pyrazole 3a and pyrazoline 5a were found to be the most selective and effective BChE inhibitors over AChE. The data collected from the single-crystal X-ray diffraction analysis of compound 5a were then applied in a docking simulation to determine the potential binding interactions that were responsible for the anti-BChE activity. The results obtained signify the potential of these pyrazole and pyrazoline scaffolds to be developed as therapeutic agents against inflammatory conditions and Alzheimer's disease.

Aromatic Esters of the Crinane Amaryllidaceae Alkaloid Ambelline as Selective Inhibitors of Butyrylcholinesterase.

A total of 20 derivatives (1-20) of the crinane-type alkaloid ambelline were synthesized. These semisynthetic derivatives were assessed for their potency to inhibit both acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). To predict central nervous system (CNS) availability, logBB was calculated, and the data correlated well with those obtained from the parallel artificial membrane permeability assay (PAMPA). All compounds should be able to permeate the blood-brain barrier (BBB) according to the obtained results. A total of 7 aromatic derivatives (5, 6, 7, 9, 10, 12, and 16) with different substitution patterns showed inhibitory potency against human serum BuChE (IC50 < 5 µM), highlighting the three top-ranked compounds as follows: 11-O-(1-naphthoyl)ambelline (16), 11-O-(2-methylbenzoyl)ambelline (6), and 11-O-(2-methoxybenzoyl)ambelline (9) with IC50 values of 0.10 ± 0.01, 0.28 ± 0.02, and 0.43 ± 0.04 µM, respectively. Notably, derivatives 6, 7, 9, and 16 displayed selective human BuChE (hBuChE) inhibition profiles with a selectivity index > 100. The in vitro results were supported by computational studies predicting plausible binding modes of the compounds in the active sites of hBuChE.

Synthesis and cholinesterase inhibiting potential of A-ring azepano- and 3-amino-3,4-seco-triterpenoids.

In this study, a series of A-ring azepano- and 3-amino-3,4-seco-derivatives were synthesized from betulin, oleanolic, ursolic and glycyrrhetinic acids aiming to develop new cholinesterase inhibitors. Azepanobetulin, azepanoerythrodiol and azepanouvaol were modified to give amide and tosyl derivatives, while azepano-anhydrobetulines and azepano-glycyrrhetols were obtained for the first time. Oleanane and ursane type 3-amino-3,4-seco-4(23)-en triterpenic alcohols were synthesized by reducing the corresponding 2-cyano-derivatives accessible from Beckmann type 2 rearrangements. The compounds were screened in colorimetric Ellman's assays to determine their ability to act as inhibitors for the enzymes acetylcholinesterase (AChE, from electric eel) and butyrylcholinesterase (BChE, from equine serum). While most of these compounds were only moderate inhibitors for AChE, several of them were shown to be inhibitors for BChE acting as mixed-type inhibitors. Azepanobetulin 1, its C28-amide derivatives 7 and 8, azepano-11-deoxo-glycyrrhetol 12 and azepanouvaol 18 held inhibition constants Ki ranging between 0.21 ± 0.06 to 0.68 ± 0.19 µM. Thus, they were approximately 4 to 10 times more active than standard galantamine hydrobromide. For all of the compounds reasonably high docking scores for BChE were obtained being in good agreement with the experimental results from the enzymatic studies. As a result, A-ring azepano-triterpenoids were found to be new scaffolds for the development of BChE inhibitors.

Synthesis, in vitro screening and molecular docking of isoquinolinium-5-carbaldoximes as acetylcholinesterase and butyrylcholinesterase reactivators.

The series of symmetrical and unsymmetrical isoquinolinium-5-carbaldoximes was designed and prepared for cholinesterase reactivation purposes. The novel compounds were evaluated for intrinsic acetylcholinesterase (AChE) or butyrylcholinesterase (BChE) inhibition, when the majority of novel compounds resulted with high inhibition of both enzymes and only weak inhibitors were selected for reactivation experiments on human AChE or BChE inhibited by sarin, VX, or paraoxon. The AChE reactivation for all used organophosphates was found negligible if compared to the reactivation ability of obidoxime. Importantly, two compounds were found to reactivate BChE inhibited by sarin or VX better to obidoxime at human attainable concentration. One compound resulted as better reactivator of NEMP (VX surrogate)-inhibited BChE than obidoxime. The in vitro results were further rationalized by molecular docking studies showing future directions on designing potent BChE reactivators.

Design, synthesis and cholinesterase inhibitory properties of new oxazole benzylamine derivatives.

The enzymes acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are primary targets in attenuating the symptoms of neurodegenerative diseases. Their inhibition results in elevated concentrations of the neurotransmitter acetylcholine which supports communication among nerve cells. It was previously shown for trans-4/5-arylethenyloxazole compounds to have moderate AChE and BChE inhibitory properties. A preliminary docking study showed that elongating oxazole molecules and adding a new NH group could make them more prone to bind to the active site of both enzymes. Therefore, new trans-amino-4-/5-arylethenyl-oxazoles were designed and synthesised by the Buchwald-Hartwig amination of a previously synthesised trans-chloro-arylethenyloxazole derivative. Additionally, naphthoxazole benzylamine photoproducts were obtained by efficient photochemical electrocyclization reaction. Novel compounds were tested as inhibitors of both AChE and BChE. All of the compounds exhibited binding preference for BChE over AChE, especially for trans-amino-4-/5-arylethenyl-oxazole derivatives which inhibited BChE potently (IC50 in µM range) and AChE poorly (IC50≫100 µM). Therefore, due to the selectivity of all of the tested compounds for binding to BChE, these compounds could be applied for further development of cholinesterase selective inhibitors.HIGHLIGHTSSeries of oxazole benzylamines were designed and synthesisedThe tested compounds showed binding selectivity for BChENaphthoxazoles were more potent AChE inhibitors.

Sulphonamides incorporating 1,3,5-triazine structural motifs show antioxidant, acetylcholinesterase, butyrylcholinesterase, and tyrosinase inhibitory profile.

A series of 16 novel benzenesulfonamides incorporating 1,3,5-triazine moieties substituted with aromatic amines, dimethylamine, morpholine and piperidine were investigated. These compounds were assayed for antioxidant properties by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, 2,2`-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical decolarisation assay and metal chelating methods. They were also investigated as inhibitors of acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and tyrosinase, which are associated with several diseases such as Alzheimer, Parkinson and pigmentation disorders. These benzenesulfonamides showed moderate DPPH radical scavenging and metal chelating activity, and low ABTS cation radical scavenging activity. Compounds 2 b, 3d and 3 h showed inhibitory potency against AChE with % inhibition values of >90. BChE was also effectively inhibited by most of the synthesised compounds with >90% inhibition potency. Tyrosinase was less inhibited by these compounds.

Synthesis of calix[4]azacrown substituted sulphonamides with antioxidant, acetylcholinesterase, butyrylcholinesterase, tyrosinase and carbonic anhydrase inhibitory action.

A series of novel calix[4]azacrown substituted sulphonamide Schiff bases was synthesised by the reaction of calix[4]azacrown aldehydes with different substituted primary and secondary sulphonamides. The obtained novel compounds were investigated as inhibitors of six human (h) isoforms of carbonic anhydrases (CA, EC 4.2.1.1). Their antioxidant profile was assayed by various bioanalytical methods. The calix[4]azacrown substituted sulphonamide Schiff bases were also investigated as inhibitors of acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and tyrosinase enzymes, associated with several diseases such as Alzheimer, Parkinson, and pigmentation disorders. The new sulphonamides showed low to moderate inhibition against hCAs, AChE, BChE, and tyrosinase enzymes. However, some of them possessed relevant antioxidant activity, comparable with standard antioxidants used in the study.

Exploration of dual fatty acid amide hydrolase and cholinesterase inhibitory potential of some 3-hydroxy-3-phenacyloxindole analogs.

The dual inhibition of fatty acid amide hydrolase (FAAH) and cholinesterases (ChEs) has recently egressed as a novel strategy for the management of neurodegeneration. In the present work, a library of 3-hydroxy-3-phenacyloxindole analogs was screened for FAAH and ChEs (acetylcholinesterase [AChE]/butyrylcholinesterase [BuChE]) inhibition. 1-Benzyl-3-hydroxy-3-(2',4'-dibromophenacyl)oxindole (16), the most promising compound, showed a balanced multifunctional profile with FAAH (IC50 = 8.7 ± 0.3 nM, competitive and reversible), AChE (IC50 = 28 ± 3 nM, mixed and reversible), and BuChE (IC50 = 65 ± 8 nM, mixed and reversible) inhibition. The structure-activity relationship study predicted multifarious fundamental aspects crucial for the potency of these analogs. Furthermore, the structural geometry and rigidness bestowed by the oxindole moiety resulted in improved adherence of the compounds within the binding pockets of the target enzymes. Molecular docking studies of the docked conformations acknowledged numerous interactions for trenchant stabilization of inhibitor-enzyme complexes. Binding interaction and conformational alignment studies of stereoisomers of the lead inhibitors highlighted the importance of the (S)-stereochemistry at C-3 of the oxindole scaffold for potency and selectivity. Compound 16 also displayed an antioxidant potential surpassing that of ascorbic acid, and it was non-neurotoxic. In silico molecular and ADMET properties anticipated druglikeness of the test compounds for oral use. Thus, compound 16 emerged as a new and interesting multifaceted candidate that could further be explored for its potential multitargeted role in the discovery of drugs for the treatment of Alzheimer's disease.

Thieno[2,3-b]pyridine amines: Synthesis and evaluation of tacrine analogs against biological activities related to Alzheimer's disease.

In search of safer tacrine analogs, various thieno[2,3-b]pyridine amine derivatives were synthesized and evaluated for their inhibitory activity against cholinesterases (ChEs). Among the synthesized compounds, compounds 5e and 5d showed the highest activity towards acetylcholinesterase and butyrylcholinesterase, with IC50 values of 1.55 and 0.23 µM, respectively. The most active ChE inhibitors (5e and 5d) were also candidates for further complementary assays, such as kinetic and molecular docking studies as well as studies on inhibitory activity towards amyloid-beta (ßA) aggregation and ß-secretase 1, neuroprotectivity, and cytotoxicity against HepG2 cells. Our results indicated efficient anti-Alzheimer's activity of the synthesized compounds.

Synthesis of Benzimidazole-Based Analogs as Anti Alzheimer's Disease Compounds and Their Molecular Docking Studies.

We synthesized 10 analogs of benzimidazole-based thiosemicarbazide 1 (a-j) and 13 benzimidazole-based Schiff bases 2 (a-m), and characterized by various spectroscopic techniques and evaluated in vitro for acetylcholinesterase (AchE) and butyrylcholinesterase (BchE) inhibition activities. All the synthesized analogs showed varying degrees of acetylcholinesterase and butyrylcholinesterase inhibitory potentials in comparison to the standard drug (IC50 = 0.016 and 4.5 µM. Amongst these analogs 1 (a-j), compounds 1b, 1c, and 1g having IC50 values 1.30, 0.60, and 2.40 µM, respectively, showed good acetylcholinesterase inhibition when compared with the standard. These compounds also showed moderate butyrylcholinesterase inhibition having IC50 values of 2.40, 1.50, and 2.40 µM, respectively. The rest of the compounds of this series also showed moderate to weak inhibition. While amongst the second series of analogs 2 (a-m), compounds 2c, 2e, and 2h having IC50 values of 1.50, 0.60, and 0.90 µM, respectively, showed moderate acetylcholinesterase inhibition when compared to donepezil. Structure Aactivity Relation of both synthesized series has been carried out. The binding interactions between the synthesized analogs and the enzymes were identified through molecular docking simulations.

Tannic acid as a natural antioxidant compound: Discovery of a potent metabolic enzyme inhibitor for a new therapeutic approach in diabetes and Alzheimer's disease.

Multiple studies have been recorded on the synthesis and design of multi-aim anti-Alzheimer molecules. Using dual butyrylcholinesterase/acetylcholinesterase inhibitor molecules has attracted more interest in the therapy for Alzheimer's disease. In this study, a tannic acid compound showed excellent inhibitory effects against acetylcholine esterase (AChE), α-glycosidase, α-amylase, and butyrylcholinesterase (BChE). IC50 values of tannic acid obtained 11.9 nM against α-glycosidase and 3.3 nM against α-amylase, respectively. In contrast, Ki values were found of 50.96 ± 2.18 µM against AChE and 53.17 ± 4.47 µM against BChE. α-Glycosidase inhibitor compounds can be utilized as a novel group of antidiabetic drugs. By competitively decreasing glycosidase activity, these inhibitor molecules help to hamper the fast breakdown of sugar molecules and thereby control the blood sugar level.

New 4-N-phenylaminoquinoline derivatives as antioxidant, metal chelating and cholinesterase inhibitors for Alzheimer's disease.

A series of new 4-N-phenylaminoquinoline derivatives were designed, synthesized, and their anticholinesterase activities, 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, metal-chelating ability were tested. Among them, compounds 11j, 11k and 11l had comparable inhibition activities to reference drug galantamine both in AChE and in BChE. Especially, compound 11j revealed the most potent inhibition to eeAChE and eqBChE with IC50 values of 1.20 µM and 18.52 µM, respectively. Furthermore, both kinetic analysis of AChE inhibition and molecular docking study indicated that compound 11j was mixed-type inhibitor, binding simultaneously to the catalytic anionic site (CAS) and the peripheral anionic site (PAS) of AChE, and propidium iodide displacement assay showed significant displacement of propidium iodide with compound 11k (25.80%) from PAS of eeAChE. More importantly, compound 11l displayed excellent DPPH radical scavenging activity (84% at 1 mg/mL), and its EC50 value was 0.328 µM. In addition, compounds 11a, 11j, 11k and 11l exhibited obvious biometal chelating abilities toward Al3+, Fe2+, Cu2+ and Zn2+ ions. Taken together, 4-N-phenylaminoquinoline derivatives targeting multiple pathogenetic factors deserve further investigation for treatment of AD.

Design and Synthesis of Selective Acetylcholinesterase Inhibitors: Arylisoxazole-Phenylpiperazine Derivatives.

In this work, a novel series of arylisoxazole-phenylpiperazines were designed, synthesized, and evaluated toward acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Our results revealed that [5-(2-chlorophenyl)-1,2-oxazol-3-yl](4-phenylpiperazin-1-yl)methanone (5c) was the most potent AChE inhibitor with IC50 of 21.85 µm. It should be noted that most of synthesized compounds showed no BChE inhibitory activity and [5-(2-fluorophenyl)-1,2-oxazol-3-yl](4-phenylpiperazin-1-yl)methanone (5a) was the most active anti-BChE derivative (IC50 =51.66 µm). Also, kinetic studies for the AChE and BChE inhibitory activity of compounds 5c and 5a confirmed that they have simultaneously bound to the catalytic site (CS) and peripheral anionic site (PAS) of both AChE and BChE. Furthermore, docking study of compound 5c showed desired interactions of that compound with amino acid residues located in the active and peripheral anionic sites. Compound 5c was also evaluated for its BACE1 inhibitory activity and demonstrated IC50 =76.78 µm. Finally, neuroprotectivity of compound 5c on Aß-treated neurotoxicity in PC12 cells depicted low activity.

Natural Multi-Target Inhibitors of Cholinesterases and Monoamine Oxidase Enzymes with Antioxidant Potential from Skin Extracts of Hypsiboas cordobae and Pseudis minuta (Anura: Hylidae).

Alzheimer's disease (AD) is the most common cause of dementia, characterized by loss of selective neuronal and normal brain functions. Every year, ten million new cases are diagnosed worldwide. AD is a complex disease associated with all kind of different pathways, making their simultaneous modulation necessary. Nowadays anti-AD treatments are focused on enzymatic inhibitors. The study of the amphibians' skin had acquired great importance in the fields of biology and human health and represents an attractive and novel source for natural compounds with high potential in the development of new drugs. The present work exhibits the power of amphibian skins as a source of bioactive compounds. Herein we report the activity of extracts of two species from Hylidae family (H. cordobae and P. minuta) as reversible inhibitors of acetylcholinesterase and butyrylcholinesterase enzymes. Furthermore, the extracts inhibit MAO-B enzyme and showed antioxidant activities, acting on four important pathways of AD.

In Vitro and In Silico Acetylcholinesterase Inhibitory Activity of Thalictricavine and Canadine and Their Predicted Penetration across the Blood-Brain Barrier.

In recent studies, several alkaloids acting as cholinesterase inhibitors were isolated from Corydalis cava (Papaveraceae). Inhibitory activities of (+)-thalictricavine (1) and (+)-canadine (2) on human acetylcholinesterase (hAChE) and butyrylcholinesterase (hBChE) were evaluated with the Ellman's spectrophotometric method. Molecular modeling was used to inspect the binding mode of compounds into the active site pocket of hAChE. The possible permeability of 1 and 2 through the blood⁻brain barrier (BBB) was predicted by the parallel artificial permeation assay (PAMPA) and logBB calculation. In vitro, 1 and 2 were found to be selective hAChE inhibitors with IC50 values of 0.38 ± 0.05 µM and 0.70 ± 0.07 µM, respectively, but against hBChE were considered inactive (IC50 values > 100 µM). Furthermore, both alkaloids demonstrated a competitive-type pattern of hAChE inhibition and bind, most probably, in the same AChE sub-site as its substrate. In silico docking experiments allowed us to confirm their binding poses into the active center of hAChE. Based on the PAMPA and logBB calculation, 2 is potentially centrally active, but for 1 BBB crossing is limited. In conclusion, 1 and 2 appear as potential lead compounds for the treatment of Alzheimer's disease.

Phenolic composition, antioxidant activity, anticholinesterase potential and modulatory effects of aqueous extracts of some seaweeds on ß-amyloid aggregation and disaggregation.

Context: Seaweeds contain bioactive compounds with different biological activities. They are used as functional ingredients for the development of therapeutic agents to combat degenerative diseases. Objective: This study investigated the phenolic composition, antioxidant activity, cholinesterase inhibitory and anti-amyloidogenic activities of aqueous extracts of Gracilaria beckeri (J.Agardh) Papenfuss (Gracilariaceae) (RED-AQ), Ecklonia maxima (Osbeck) Papenfuss (Lessoniaceae) (ECK-AQ), Ulva rigida (C.Agardh) Linnaeus (Ulvaceae) (URL-AQ) and Gelidium pristoides (Turner) Kützing (Gelidiaceae) (GEL-AQ). Materials and methods: Phenolic composition of the seaweed extracts was determined using liquid chromatography mass spectrometry. Radical scavenging and metal chelating activities were assessed in vitro. The effect of the extracts (21-84 µg/mL) on acetylcholinesterase and butyrylcholinesterase activities were also investigated using an in vitro colorimetric assay. Transmission electron microscope and thioflavin-T fluorescence assay were used to examine the anti-amyloidogenic activities of the extracts. Results: Phloroglucinol, catechin, epicatechin 3-glucoside were identified in the extracts. ECK-AQ (IC50=30.42 and 280.47 µg/mL) exhibited the highest OH• scavenging and metal chelating activities, while RED-AQ (41.23 and 334.45 µg/mL) exhibited the lowest. Similarly, ECK-AQ (IC50 = 49.41 and 52.11 µg/mL) exhibited higher inhibitory effects on acetylcholinesterase and butyrylcholinesterase activities, while RED-AQ (64.56 and 63.03 µg/mL) showed the least activities. Rapid formation of ß-amyloid (Aß1-42) fibrils and aggregates was observed in electron micrographs of the control after 72 and 96 h. The reduction of Aß1-42 aggregates occurred after co-treatment with the seaweed extracts. Discussion and conclusion: ECK-AQ, GEL-AQ, URL-AQ and RED-AQ may possess neuroprotective potential and could be explored for the management of Alzheimer's disease.

Isolation of quercetin and mandelic acid from Aesculus indica fruit and their biological activities.

BACKGROUND: In this study Aesculus indica fruit was subjected to isolation of phytochemicals. Two antioxidants quercetin and Mandelic acid were isolated in pure state. The free radical scavenging and acetyl choline esterase inhibitory potential of the crude extract and sub fractions were also determined. RESULTS: The antioxidant capacity of crude extract, fractions and isolated compounds were determined by DPPH and ABTS methods. Folin-Ciocalteu reagent method was used to estimate the total phenolic contents and were found to be 78.34 ± 0.96, 44.16 ± 1.05, 65.45 ± 1.29, 37.85 ± 1.44 and 50.23 ± 2.431 (mg/g of gallic acid) in crude extract, ethyl acetate, chloroform, n-hexane and aqueous fractions respectively. The flavonoid concentration in crude extract, ethyl acetate, chloroform, n-hexane and aqueous fraction were; 85.30 ± 1.20, 53.80 ± 1.07, 77.50 ± 1.12, 26.30 ± 1.35 and 37.78 ± 1.25 (mg/g of quercetin) respectively. The chloroform fraction was more potent against enzymes, acetyl choline esterase and butyryl choline esterase (IC50 = 85 and 160 µg/ml respectively). The phenolic compounds in the crude extract and fractions were determined using HPLC standard method. Chlorogenic acid, quercetin, phloroglucinol, rutin, mandelic acid and hydroxy benzoic acid were detected at retention times 6.005, 10.062, 22.623, 30.597, 35.490 and 36.211 in crude extract and different fractions. The ethyl acetate fraction was rich in the targeted compounds and was therefore subjected to column isolation. The HPLC chromatogram of isolated compounds showed single peak at specified retention times which confirms their isolation in pure state. The isolated compounds were then characterized by FTIR and NMR spectrophotometric techniques. CONCLUSION: The Aesculus indica fruit extracts showed antioxidant and anticholine esterase inhibitory potentials. Two bioactive compounds were isolated in the pure form ethyl acetate fraction. From results it was concluded that the fruit of this plant could be used to minimize oxidative stress caused by reactive oxygen species.

Design, synthesis, and biological evaluation of selective and potent Carbazole-based butyrylcholinesterase inhibitors.

Alzheimer's disease (AD) is the most common form of dementia. Inhibition of BChE might be a useful therapeutic target for AD. A new series of Carbazole-Benzyl Pyridine derivatives were designed synthesized and evaluated as butyrylcholinesterase (BChE) inhibitors. In vitro assay revealed that all of the derivatives had selective and potent anti- BChE activities. 3-((9H-Carbazol-9-yl)methyl)-1-(4-chlorobenzyl)pyridin-1-ium chloride (compound 8f) had the most potent anti-BChE activity (IC50 value = 0.073 µM), the highest BChE selectivity and mixed-type inhibition. Docking study revealed that 8f interacted with the peripheral site, the choline binding site, catalytic site and the acyl pocket of BChE. Physicochemical properties were accurate to Lipinski's rule. In addition, compound 8f demonstrated neuroprotective activity at 10 µM. This compound could also inhibit AChE-induced and self-induced Aß peptide aggregation at concentration of 100 µM and 10 µM respectively. The in-vivo study showed that compound 8f in 10 mg/kg increased the time spent in target quadrant in the probe day and decreased mean training period scape latency in rats. All results suggest that new sets of potent selective inhibitors of BChE have a therapeutic potential for the treatment of AD.