Radiosynthesis and whole-body distribution in mice of a 18 F-labeled azepino[4,3-b]indole-1-one derivative with multimodal activity for the treatment of Alzheimer's disease.

Recently, the azepino[4,3-b]indole-1-one derivative 1 showed in vitro nanomolar inhibition against butyrylcholinesterase (BChE), the ChE isoform that plays a role in the progression and pathophysiology of Alzheimer's disease (AD), and protects against N-methyl- d-aspartate-induced neuronal toxicity. Three 9-R-substituted (R = F, Br, OMe) congeners were investigated. The 9-F derivative (2a) was found more potent as BChE inhibitors (half-maximal inhibitory concentration value = 21 nM) than 2b (9-Br) and 2c (9-OMe), achieving a residence time (38 s), assessed by surface plasmon resonance, threefold higher than that of 1. To progress in featuring the in vivo pharmacological characterization of 2a, herein the 18 F-labeled congener 2a was synthesized, by applying the aromatic 18 F-fluorination method, and its whole-body distribution in healthy mice, including brain penetration, was evaluated through positron emission tomography imaging. [18 F]2a exhibited a rapid and high brain uptake (3.35 ± 0.26% ID g-1 at 0.95 ± 0.15 min after injection), followed by a rapid clearance (t1/2 = 6.50 ± 0.93 min), showing good blood-brain barrier crossing. After a transient liver accumulation of [18 F]2a, the intestinal and urinary excretion was quantified. Finally, ex vivo pharmacological experiments in mice showed that the unlabeled 2a affects the transmitters' neurochemistry, which might be favorable to reverse cognition impairment in mild-to-moderate AD-related dementias.

Chemical and Biological Evaluation of Novel 1H-Chromeno[3,2-c]pyridine Derivatives as MAO Inhibitors Endowed with Potential Anticancer Activity.

About twenty molecules sharing 1H-chromeno[3,2-c]pyridine as the scaffold and differing in the degree of saturation of the pyridine ring, oxidation at C10, 1-phenylethynyl at C1 and 1H-indol-3-yl fragments at C10, as well as a few small substituents at C6 and C8, were synthesized starting from 1,2,3,4-tetrahydro-2-methylchromeno[3,2-c]pyridin-10-ones (1,2,3,4-THCP-10-ones, 1) or 2,3-dihydro-2-methyl-1H-chromeno[3,2-c]pyridines (2,3-DHPCs, 2). The newly synthesized compounds were tested as inhibitors of the human isoforms of monoamine oxidase (MAO A and B) and cholinesterase (AChE and BChE), and the following main SARs were inferred: (i) The 2,3-DHCP derivatives 2 inhibit MAO A (IC50 about 1 µM) preferentially; (ii) the 1,2,3,4-THCP-10-one 3a, bearing the phenylethynyl fragment at C1, returned as a potent MAO B inhibitor (IC50 0.51 µM) and moderate inhibitor of both ChEs (IC50s 7-8 µM); (iii) the 1H-indol-3-yl fragment at C10 slightly increases the MAO B inhibition potency, with the analog 6c achieving MAO B IC50 of 3.51 µM. The MAO B inhibitor 3a deserves further pharmacological studies as a remedy in the symptomatic treatment of Parkinson's disease and neuroprotectant for Alzheimer's disease. Besides the established neuroprotective effects of MAO inhibitors, the role of MAOs in tumor insurgence and progression has been recently reported. Herein, antiproliferative assays with breast (MCF-7), colon (HCT116) and cisplatin-resistant ovarian (SK-OV-3) tumor cells revealed that the 10-indolyl-bearing 2,3,4,10-THCP analog 6c exerts anti-tumor activity with IC50s in the range 4.83-11.3 µM.

Synthesis of Novel Benzo[b][1,6]naphthyridine Derivatives and Investigation of Their Potential as Scaffolds of MAO Inhibitors.

In this work, 2-alkyl-10-chloro-1,2,3,4-tetrahydrobenzo[b][1,6]naphthyridines were obtained and their reactivity was studied. Novel derivatives of the tricyclic scaffold, including 1-phenylethynyl (5), 1-indol-3-yl (8), and azocino[4,5-b]quinoline (10) derivatives, were synthesized and characterized herein for the first time. Among the newly synthesized derivatives, 5c-h proved to be MAO B inhibitors with potency in the low micromolar range. In particular, the 1-(2-(4-fluorophenyl)ethynyl) analog 5g achieved an IC50 of 1.35 µM, a value close to that of the well-known MAO B inhibitor pargyline.

Investigation on Novel E/Z 2-Benzylideneindan-1-One-Based Photoswitches with AChE and MAO-B Dual Inhibitory Activity.

The multitarget therapeutic strategy, as opposed to the more traditional 'one disease-one target-one drug', may hold promise in treating multifactorial neurodegenerative syndromes, such as Alzheimer's disease (AD) and related dementias. Recently, combining a photopharmacology approach with the multitarget-directed ligand (MTDL) design strategy, we disclosed a novel donepezil-like compound, namely 2-(4-((diethylamino)methyl)benzylidene)-5-methoxy-2,3-dihydro-1H-inden-1-one (1a), which in the E isomeric form (and about tenfold less in the UV-B photo-induced isomer Z) showed the best activity as dual inhibitor of the AD-related targets acetylcholinesterase (AChE) and monoamine oxidase B (MAO-B). Herein, we investigated further photoisomerizable 2-benzylideneindan-1-one analogs 1b-h with the unconjugated tertiary amino moiety bearing alkyls of different bulkiness and lipophilicity. For each compound, the thermal stable E geometric isomer, along with the E/Z mixture as produced by UV-B light irradiation in the photostationary state (PSS, 75% Z), was investigated for the inhibition of human ChEs and MAOs. The pure E-isomer of the N-benzyl(ethyl)amino analog 1h achieved low nanomolar AChE and high nanomolar MAO-B inhibition potencies (IC50s 39 and 355 nM, respectively), whereas photoisomerization to the Z isomer (75% Z in the PSS mixture) resulted in a decrease (about 30%) of AChE inhibitory potency, and not in the MAO-B one. Molecular docking studies were performed to rationalize the different E/Z selectivity of 1h toward the two target enzymes.

Synthesis of 8-phenyl substituted 3-benzazecines with allene moiety, their thermal rearrangement and evaluation as acetylcholinesterase inhibitors.

Various 4'-R-substituted phenyl azacyclic allenes were synthesized in good yields, and their thermal transformations were studied. For the first time, the obtained rearrangement products-new N-bridged cyclopenta[a]indenes, and the corresponding parent allenes were evaluated as potential inhibitors of acetyl- and butyrylcholinesterase. Among the tested compounds, the allene derivative 2g proved to competitively inhibit human AChE with inhibition constant value (Ki) in the low micromolar range.

Assessing the Role of a Malonamide Linker in the Design of Potent Dual Inhibitors of Factor Xa and Cholinesterases.

The rational discovery of new peptidomimetic inhibitors of the coagulation factor Xa (fXa) could help set more effective therapeutic options (to prevent atrial fibrillation). In this respect, we explored the conformational impact on the enzyme inhibition potency of the malonamide bridge, compared to the glycinamide one, as a linker connecting the P1 benzamidine anchoring moiety to the P4 aryl group of novel selective fXa inhibitors. We carried out structure-activity relationship (SAR) studies aimed at investigating para- or meta-benzamidine as the P1 basic group as well as diversely decorated aryl moieties as P4 fragments. To this end, twenty-three malonamide derivatives were synthesized and tested as inhibitors of fXa and thrombin (thr); the molecular determinants behind potency and selectivity were also studied by employing molecular docking. The malonamide linker, compared to the glycinamide one, does significantly increase anti-fXa potency and selectivity. The meta-benzamidine (P1) derivatives bearing 2',4'-difluoro-biphenyl as the P4 moiety proved to be highly potent reversible fXa-selective inhibitors, achieving inhibition constants (Ki) in the low nanomolar range. The most active compounds were also tested against cholinesterase (ChE) isoforms (acetyl- or butyrylcholinesterase, AChE, and BChE), and some of them returned single-digit micromolar inhibition potency against AChE and/or BChE, both being drug targets for symptomatic treatment of mild-to-moderate Alzheimer's disease. Compounds 19h and 22b were selected as selective fXa inhibitors with potential as multimodal neuroprotective agents.

Synthesis of Isomeric 3-Benzazecines Decorated with Endocyclic Allene Moiety and Exocyclic Conjugated Double Bond and Evaluation of Their Anticholinesterase Activity.

Transformations of 1-methoxymethylethynyl substituted isoquinolines triggered by terminal alkynes in alcohols were studied and new 3-benzazecine-containing compounds synthesized, such as 6-methoxymethyl-3-benzazecines incorporating an endocyclic C6-C8 allene fragment and the -ylidene derivatives 6-methoxymethylene-3-benzazecines. The reaction mechanisms were investigated and a preliminary in vitro screening of their potential inhibitory activities against human acetyl- and butyrylcholinesterases (AChE and BChE) and monoamine oxidases A and B (MAO-A and MAO-B) showed that the allene compounds were more potent than the corresponding -ylidene ones as selective AChE inhibitors. Among the allenes, 3e (R3 = CH2OMe) was found to be a competitive AChE inhibitor with a low micromolar inhibition constant value (Ki = 4.9 µM), equipotent with the corresponding 6-phenyl derivative 3n (R3 = Ph, Ki = 4.5 µM), but 90-fold more water-soluble.

First-in-Class Isonipecotamide-Based Thrombin and Cholinesterase Dual Inhibitors with Potential for Alzheimer Disease.

Recently, the direct thrombin (thr) inhibitor dabigatran has proven to be beneficial in animal models of Alzheimer's disease (AD). Aiming at discovering novel multimodal agents addressing thr and AD-related targets, a selection of previously and newly synthesized potent thr and factor Xa (fXa) inhibitors were virtually screened by the Multi-fingerprint Similarity Searching aLgorithm (MuSSeL) web server. The N-phenyl-1-(pyridin-4-yl)piperidine-4-carboxamide derivative 1, which has already been experimentally shown to inhibit thr with a Ki value of 6 nM, has been flagged by a new, upcoming release of MuSSeL as a binder of cholinesterase (ChE) isoforms (acetyl- and butyrylcholinesterase, AChE and BChE), as well as thr, fXa, and other enzymes and receptors. Interestingly, the inhibition potency of 1 was predicted by the MuSSeL platform to fall within the low-to-submicromolar range and this was confirmed by experimental Ki values, which were found equal to 0.058 and 6.95 µM for eeAChE and eqBChE, respectively. Thirty analogs of 1 were then assayed as inhibitors of thr, fXa, AChE, and BChE to increase our knowledge of their structure-activity relationships, while the molecular determinants responsible for the multiple activities towards the target enzymes were rationally investigated by molecular cross-docking screening.

Homobivalent Lamellarin-Like Schiff Bases: In Vitro Evaluation of Their Cancer Cell Cytotoxicity and Multitargeting Anti-Alzheimer's Disease Potential.

Marine alkaloids belonging to the lamellarins family, which incorporate a 5,6-dihydro-1-phenylpyrrolo[2,1-a]isoquinoline (DHPPIQ) moiety, possess various biological activities, spanning from antiviral and antibiotic activities to cytotoxicity against tumor cells and the reversal of multidrug resistance. Expanding a series of previously reported imino adducts of DHPPIQ 2-carbaldehyde, novel aliphatic and aromatic Schiff bases were synthesized and evaluated herein for their cytotoxicity in five diverse tumor cell lines. Most of the newly synthesized compounds were found noncytotoxic in the low micromolar range (<30 µM). Based on a Multi-fingerprint Similarity Search aLgorithm (MuSSeL), mainly conceived for making protein drug target prediction, some DHPPIQ derivatives, especially bis-DHPPIQ Schiff bases linked by a phenylene bridge, were prioritized as potential hits addressing Alzheimer's disease-related target proteins, such as cholinesterases (ChEs) and monoamine oxidases (MAOs). In agreement with MuSSeL predictions, homobivalent para-phenylene DHPPIQ Schiff base 14 exhibited a noncompetitive/mixed inhibition of human acetylcholinesterase (AChE) with Ki in the low micromolar range (4.69 µM). Interestingly, besides a certain inhibition of MAO A (50% inhibition of the cell population growth (IC50) = 12 µM), the bis-DHPPIQ 14 showed a good inhibitory activity on self-induced ß-amyloid (Aß)1-40 aggregation (IC50 = 13 µM), which resulted 3.5-fold stronger than the respective mono-DHPPIQ Schiff base 9.

Reductive domino reaction to access chromeno[2,3-c]isoquinoline-5-amines with antiproliferative activities against human tumor cells.

An interaction of homophthalonitrile with salicylaldehydes proceeds as a novel domino reaction and results in the formation of nineteen 12H-chromeno[2,3-c]isoquinoline-5-amine derivatives. Four new bonds and two cycles are forged in a single synthetic operation, employing cheap and eco-friendly ammonium formate, acting both as a catalyst and a reducing agent. The in vitro cytotoxicity tests revealed antiproliferative activities against five human tumor cell lines, including the cisplatin-resistant ovarian carcinoma one (A2780cp8), with inhibitory potency data (IC50) in the low micromolar range in most cases. Molecular docking calculations and fluorescence quenching studies revealed possible binding properties with DNA of the active compounds.

Pharmacophore Modeling and 3D-QSAR Study of Indole and Isatin Derivatives as Antiamyloidogenic Agents Targeting Alzheimer's Disease.

Thirty-six novel indole-containing compounds, mainly 3-(2-phenylhydrazono) isatins and structurally related 1H-indole-3-carbaldehyde derivatives, were synthesized and assayed as inhibitors of beta amyloid (Aß) aggregation, a hallmark of pathophysiology of Alzheimer's disease. The newly synthesized molecules spanned their IC50 values from sub- to two-digit micromolar range, bearing further information into structure-activity relationships. Some of the new compounds showed interesting multitarget activity, by inhibiting monoamine oxidases A and B. A cell-based assay in tau overexpressing bacterial cells disclosed a promising additional activity of some derivatives against tau aggregation. The accumulated data of either about ninety published and thirty-six newly synthesized molecules were used to generate a pharmacophore hypothesis of antiamyloidogenic activity exerted in a wide range of potencies, satisfactorily discriminating the 'active' compounds from the 'inactive' (poorly active) ones. An atom-based 3D-QSAR model was also derived for about 80% of 'active' compounds, i.e., those achieving finite IC50 values lower than 100 µM. The 3D-QSAR model (encompassing 4 PLS factors), featuring acceptable predictive statistics either in the training set (n = 45, q2 = 0.596) and in the external test set (n = 14, r2ext = 0.695), usefully complemented the pharmacophore model by identifying the physicochemical features mainly correlated with the Aß anti-aggregating potency of the indole and isatin derivatives studied herein.

Oxazepam-Dopamine Conjugates Increase Dopamine Delivery into Striatum of Intact Rats.

The neurotransmitter dopamine (DA) was covalently linked to oxazepam (OXA), a well-known positive allosteric modulator of γ-aminobutyric acid type-A (GABAA) receptor, through a carbamate linkage (4) or a succinic spacer (6). These conjugates were synthesized with the aim of improving the delivery of DA into the brain and enhancing GABAergic transmission, which may be useful for the long-term treatment of Parkinson disease (PD). Structure-based permeability properties, in vitro stability, and blood-brain barrier (BBB) permeability studies led to identify the OXA-DA carbamate conjugate 4a as the compound better combining sufficient stability and ability to cross BBB. Finally, in vivo microdialysis experiments in freely moving rats demonstrated that 4a (20 mg/kg, i.p.) significantly increases extracellular DA levels into striatum, with a peak (more than 15-fold increase over the baseline) at about 80 min after a single administration. The stability and delivery data proved that 4a may be a promising candidate for further pharmacological studies in animal models of PD.

A second life for MAO inhibitors? From CNS diseases to anticancer therapy.

Monoamine oxidases A and B (MAO A, B) are ubiquitous enzymes responsible for oxidative deamination of amine neurotransmitters and xenobiotics. Despite decades of studies, MAO inhibitors (MAOIs) find today limited therapeutic space as second-line drugs for the treatment of depression and Parkinson's disease. In recent years, a renewed interest in MAOIs has been raised up by several studies investigating the role of MAOs, particularly MAO A, in tumor insurgence and progression, and the efficacy of MAOIs as coadjutants in the therapy of chemoresistant tumors. In this survey, we highlight the implication of MAOs in the biochemical pathways of tumorigenesis and review the state-of-the-art of preclinical and clinical studies of MAOIs as anticancer agents used in monotherapy or in combination with antitumor chemotherapeutics.

A Critical Appraisal of the Protective Activity of Polyphenolic Antioxidants against Iatrogenic Effects of Anticancer Chemotherapeutics.

Polyphenolic compounds, encompassing flavonoids (e.g., quercetin, rutin, and cyanidin) and non-flavonoids (e.g., gallic acid, resveratrol, and curcumin), show several health-related beneficial effects, which include antioxidant, anti-inflammatory, hepatoprotective, antiviral, and anticarcinogenic properties, as well as the prevention of coronary heart diseases. Polyphenols have also been investigated for their counteraction against the adverse effects of common anticancer chemotherapeutics. This review evaluates the outcomes of clinical studies (and related preclinical data) over the last ten years, with a focus on the use of polyphenols in chemotherapy as auxiliary agents acting against oxidative stress toxicity induced by antitumor drugs. While further clinical studies are needed to establish adequate doses and optimal delivery systems, the improvement in polyphenols' metabolic stability and bioavailability, through the implementation of nanotechnologies that are currently being investigated, could improve therapeutic applications of their pharmaceutical or nutraceutical preparations in tumor chemotherapy.

Novel 6-alkyl-bridged 4-arylalkylpiperazin-1-yl derivatives of azepino[4,3-b]indol-1(2H)-one as potent BChE-selective inhibitors showing protective effects against neurodegenerative insults.

Due to the putative role of butyrylcholinesterase (BChE) in regulation of acetylcholine levels and functions in the late stages of the Alzheimer's disease (AD), the potential of selective inhibitors (BChEIs) has been envisaged as an alternative to administration of acetylcholinesterase inhibitors (AChEIs). Starting from our recent findings, herein the synthesis and in vitro evaluation of cholinesterase (ChE) inhibition of a novel series of some twenty 3,4,5,6-tetrahydroazepino[4,3-b]indol-1(2H)-one derivatives, bearing at the indole nitrogen diverse alkyl-bridged 4-arylalkylpiperazin-1-yl chains, are reported. The length of the spacers, as well as the type of arylalkyl group affected the enzyme inhibition potency and BChE/AChE selectivity. Two compounds, namely 14c (IC50 = 163 nM) and 14d (IC50 = 65 nM), bearing at the nitrogen atom in position 6 a n-pentyl- or n-heptyl-bridged 4-phenethylpiperazin-1-yl chains, respectively, proved to be highly potent mixed-type inhibitors of both equine and human BChE isoforms, showing more than two order magnitude of selectivity over AChE. The study of binding kinetics through surface plasmon resonance (SPR) highlighted differences in their BChE residence times (8 and 47 s for 14c and 14d, respectively). Moreover, 14c and 14d proved to hit other mechanisms known to trigger neurodegeneration underlying AD and other CNS disorders. Unlike 14c, compound 14d proved also capable of inhibiting by more than 60% the in vitro self-induced aggregation of neurotoxic amyloid-ß (Aß) peptide at 100 µM concentration. On the other hand, 14c was slightly better than 14d in counteracting, at 1 and 10 µM concentration, glutamate excitotoxicity, due to over-excitation of NMDA receptors, and hydrogen peroxide-induced oxidative stress assessed in neuroblastoma cell line SH-SY5Y. This paper is dedicated to Prof. Marcello Ferappi, former dean of the Faculty of Pharmacy of the University of Bari, in the occasion of his 90th birthday.

Nature-Inspired 1-Phenylpyrrolo[2,1-a]isoquinoline Scaffold for Novel Antiproliferative Agents Circumventing P-Glycoprotein-Dependent Multidrug Resistance.

Previous studies have shown that some lamellarin-resembling annelated azaheterocyclic carbaldehydes and related imino adducts, sharing the 1-phenyl-5,6-dihydropyrrolo[2,1-a]isoquinoline (1-Ph-DHPIQ) scaffold, are cytotoxic in some tumor cells and may reverse multidrug resistance (MDR) mediated by P-glycoprotein (P-gp). Herein, several novel substituted 1-Ph-DHPIQ derivatives were synthesized which carry carboxylate groups (COOH, COOEt), nitrile (CN) and Mannich bases (namely, morpholinomethyl derivatives) in the C2 position, as replacements of the already reported aldehyde group. They were evaluated for antiproliferative activity in four tumor cell lines (RD, HCT116, HeLa, A549) and for the ability of selectively inhibiting P-gp-mediated MDR. Lipophilicity descriptors and molecular docking calculations helped us in rationalizing the structure-activity relationships in the P-gp inhibition potency of the investigated 1-Ph-DHPIQs. As a main outcome, a morpholinomethyl Mannich base (8c) was disclosed which proved to be cytotoxic to all the tested tumor cell lines in the low micromolar range (IC50 < 20 µM) and to inhibit in vitro the efflux pumps P-gp and MRP1 responsible for MDR, with IC50s of 0.45 and 12.1 µM, respectively.

Novel Dual-Acting Hybrids Targeting Type-2 Cannabinoid Receptors and Cholinesterase Activity Show Neuroprotective Effects In Vitro and Amelioration of Cognitive Impairment In Vivo.

Alzheimer's disease (AD) is a neurodegenerative form of dementia characterized by the loss of synapses and a progressive decline in cognitive abilities. Among current treatments for AD, acetylcholinesterase (AChE) inhibitors have efficacy limited to symptom relief, with significant side effects and poor compliance. Pharmacological agents that modulate the activity of type-2 cannabinoid receptors (CB2R) of the endocannabinoid system by activating or blocking them have also been shown to be effective against neuroinflammation. Herein, we describe the design, synthesis, and pharmacological effects in vitro and in vivo of dual-acting compounds that inhibit AChE and butyrylcholinesterase (BChE) and target CB2R. Within the investigated series, compound 4g proved to be the most promising. It achieved IC50 values in the low micromolar to submicromolar range against both human cholinesterase isoforms while antagonizing CB2R with Ki of 31 nM. Interestingly, 4g showed neuroprotective effects on the SH-SY5Y cell line thanks to its ability to prevent oxidative stress-induced cell toxicity and reverse scopolamine-induced amnesia in the Y-maze forced alternation test in vivo.

Hansch-Type QSAR Models for the Rational Design of MAO Inhibitors: Basic Principles and Methodology.

Hansch-type regression analysis enables the derivation of quantitative structure-activity relationship (QSAR) equations correlating bioactivity data with physicochemical parameters accounting for hydrophobicity, electronic properties, and steric effects of molecules or functional groups (substituents). Two datasets of MAO A and B inhibitors were enrolled in prototypical workflows employing multiparametric stepwise regression analysis, which includes linear and nonlinear (generally quadratic) terms. The optimal choice of variables (and/or combinations thereof) along with statistical validation yielded two robust equations describing MAO B potency and B/A selectivity, which included three and one parameter(s), respectively, and explained more than 80% of y-variance (r2) with low standard deviation (s) and good statistical significance (F, Fisher value).

In-vitro and in-silico studies of annelated 1,4,7,8-tetrahydroazocine ester derivatives as nanomolar selective inhibitors of human butyrylcholinesterase.

Based on previous finding showing 2,3,6,11-tetrahydro-1H-azocino[4,5-b]indole as suitable scaffold of novel inhibitors of acetylcholinesterase (AChE), a main target of drugs for the treatment of Alzheimer's disease and related dementias, herein we investigated diverse newly and previously synthesized ß-enamino esters (and ketones) derivatives of 1,4,7,8-tetrahydroazocines (and some azonines) fused with benzene, 1H-indole, 4H-chromen-4-one and pyrimidin-4(3H)-one. Twenty derivatives of diversely annelated eight-to-nine-membered azaheterocyclic ring, prepared through domino reaction of the respective tetrahydropyridine and azepine with activated alkynes, were assayed for the inhibitory activity against AChE and butyrylcholinesterase (BChE). As a major outcome, compound 7c, an alkylamino derivative of tetrahydropyrimido[4,5-d]azocine, was found to be a highly potent BChE-selective inhibitor, which showed a noncompetitive/mixed-type inhibition mechanism against human BChE with single digit nanomolar inhibition constant (Ki = 7.8 ± 0.2 nM). The four-order magnitude BChE-selectivity of 7c clearly reflects the effect of lipophilicity upon binding to the BChE binding cavity. The ChEs' inhibition data, interpreted by chemoinformatic tools and an in-depth in-silico study (molecular docking combined with molecular dynamics calculations), not only highlighted key structural factors enhancing inhibition potency and selectivity toward BChE, but also shed light on subtle differences distinguishing the binding sites of equine BChE from the recombinant human BChE. Compound 7c inhibited P-glycoprotein with IC50 of 0.27 µM, which may support its ability to permeate blood-brain barrier, and proved to be no cytotoxic in human liver cancer cell line (HepG2) at the BChE bioactive concentrations. Overall, the biological profile allows us to envision 7c as a promising template to improve design and development of BChE-selective ligands of pharmaceutical interest, including inhibitors and fluorogenic probes.

Design, synthesis and biological evaluation of light-driven on-off multitarget AChE and MAO-B inhibitors.

Neurodegenerative diseases are multifactorial disorders characterized by protein misfolding, oxidative stress, and neuroinflammation, finally resulting in neuronal loss and cognitive dysfunctions. Nowadays, an attractive strategy to improve the classical treatments is the development of multitarget-directed molecules able to synergistically interact with different enzymes and/or receptors. In addition, an interesting tool to refine personalized therapies may arise from the use of bioactive species able to modify their activity as a result of light irradiation. To this aim, we designed and synthesized a small library of cinnamic acid-inspired isomeric compounds with light modulated activity able to inhibit acetylcholinesterase (AChE) and monoamine oxidase B (MAO-B), with remarkable selectivity over butyrylcholinesterase (BChE) and MAO-A, which have been investigated as the enzyme targets related to Alzheimer's disease (AD). The inhibitory activities were evaluated for the pure E-diastereomers and the E/Z-diastereomer mixtures, obtained upon UV irradiation. Molecular docking studies were carried out to rationalize the differences in the inhibition potency of the E and Z diastereomers of the best performing analogue 1c. Our preliminary findings may open-up the way for developing innovative multitarget photo-switch drugs against neurodegenerative diseases.