A magnetic beads-based ligand fishing method for rapid discovery of monoterpene indoles as monoamine oxidase A inhibitors from Hunteria zeylanica.

In this study, a novel magnetic bead-based ligand fishing method was developed for rapid discovery of monoterpene indoles as monoamine oxidase A inhibitors from natural products. In order to improve the screening efficiency, two different magnetic beads, i.e. amine and carboxyl terminated magnetic beads, were comprehensively compared in terms of their ability to immobilize monoamine oxidase A (MAOA), biocatalytic activity and specific adsorption rates for affinity ligands. Carboxyl terminated magnetic beads performed better for MAOA immobilization and demonstrated superior performance in ligand fishing. The MAOA immobilized magnetic beads were applied to screen novel monoamine oxidase inhibitors in an alkaloid-rich plant, Hunteria zeylanica. Twelve MAOA affinity ligands were screened out, and ten of them were identified as monoterpene indole alkaloids by HPLC-Obitrap-MS/MS. Among them, six ligands, namely geissoschizol, vobasinol, yohimbol, dihydrocorynanthenol, eburnamine and (+)-isoeburnamine which exhibited inhibitory activity against MAOA with low IC50 values. To further explore their inhibitory mechanism, enzyme kinetic analysis and molecular docking studies were conducted.

Nature as a source and inspiration for human monoamine oxidase B (hMAO-B) inhibition: A review of the recent advances in chemical modification of natural compounds.

INTRODUCTION: Over the past 5 years, we have witnessed intense research activity about the biological potential of natural products (NPs) as human monoamine oxidase B (hMAO-B) inhibitors. Despite the promising inhibitory activity, natural compounds often suffer from pharmacokinetic lissues, such as poor aqueous solubility, extensive metabolism, and low bioavailability. AREAS COVERED: This review provides an overview of the current landscape NPs as selective hMAO-B inhibitors and highlights their use as a starting scaffold to design (semi)synthetic derivatives to overcome the therapeutic (pharmacodynamic and pharmacokinetic) limitations of NPs and to obtain more robust structure-activity relationships (SARs) for each scaffold. EXPERT OPINION: All the natural scaffolds herein presented displayed a broad chemical diversity. The knowledge of their biological activity as inhibitors of hMAO-B enzyme allows the positive correlations associated with the consumption of specific food or the possible herb-drug interactions and suggests to the Medicinal Chemists how to address chemical functionalization to obtain more potent and selective compounds.

Ligand fishing of monoamine oxidase B inhibitors from Platycodon grandiflorus (Jacq.) A.DC. roots by the enzyme functionalised magnetic nanoparticles.

INTRODUCTION: As a famous traditional Chinese medicine, roots of Platycodon grandiflorus (Jacq.) A.DC. have shown multiple effects against neurodegenerative diseases. To investigate the components against Parkinson's disease (PD), the roots of P. grandiflora were selected as the research subject. OBJECTIVE: Screening and identifying of monoamine oxidase B (MAO-B) inhibitors from the roots of P. grandiflorum via enzyme functionalised magnetic nanoparticles (MNPs)-based ligand fishing combined with high-performance liquid chromatography-mass spectrometry (HPLC-MS) analysis. METHOD: MAO-B functionalised MNPs have been synthesised for screening MAO-B inhibitors from the roots of P. grandiflorum. The ligands were identified by HPLC-MS and nuclear magnetic resonance (NMR) analysis, and their anti-PD activity was evaluated via MAO-B inhibition assay and cell viability assay in vitro. RESULTS: Two MAO-B inhibitors were fished out and identified by HPLC-MS as protocatechuic aldehyde (1) and coumarin (2), with the half maximal inhibitory concentrations of 28.54 ± 0.39 and 25.39 ± 0.29 µM, respectively. Among them, 1 could also significantly increase the viability of 6-hydroxydopamine-damaged PC12 cells. CONCLUSION: The results are helpful to elucidate the anti-PD activity of the plant, and the ligand fishing method has shown good potential in discovery of MAO-B inhibitors.

Anti-Alzheimer chemical constituents of Morus macroura Miq.: chemical profiling, in silico and in vitro investigations.

Herein, we investigated both fruits and leaves of Morus macroura Miq. as a potential source of bioactive compounds against Alzheimer's disease (AD). LC-HRMS-assisted chemical profiling of its extracts showed that they are a rich source of diverse phytochemicals. Among the 29 identified compounds in both the fruit and leaf extracts, moracin D, chrysin, resveratrol, and ferulic acid were predicted to pass the human blood-brain barrier (BBB), and hence, reach their therapeutic targets in the brain. Subsequently, these compounds were subjected to a comprehensive pharmacophore-based screening for their protein targets relevant to AD using two independent software programs (i.e. Swiss Target Prediction and PharmMapper). The results of this initial virtual screening were further refined by a number of docking and molecular dynamic simulation experiments to suggest a number of crucial AD-related proteins (e.g. acetylcholine esterase, ß-secretase, and monoamine oxidase) as potential targets for these compounds. Finally, in vitro testing was performed to validate the in silico investigation's results, where chrysin, resveratrol, and ferulic acid were found to inhibit the predicted AD-related enzymes with IC50 values comparable with those of the reference inhibitors. Additionally, they were able to inhibit the aggregation of amyloid-beta, one of the hallmarks in AD pathogenesis, and to exhibit considerable antioxidant capacity. Our results highlighted Morus macroura compounds as future anti-Alzheimer chemical leads.

Luteolin, a Potent Human Monoamine Oxidase-A Inhibitor and Dopamine D4 and Vasopressin V1A Receptor Antagonist.

Luteolin, a flavonoid widely distributed in the plant kingdom, contains two benzene rings and hydroxyl groups, and this structural specificity contributes to its diverse biological activities. However, no previous studies have simultaneously investigated the therapeutic potency of luteolin isolated from a plant as an antipsychotic and antidepressant. Here, luteolin exhibited selective inhibition of hMAO-A (IC50 = 8.57 ± 0.47 µM) over hMAO-B (IC50 > 100 µM). In silico proteochemometric modeling predicted promising targets of luteolin, and verification via cell-based G protein-coupled receptor functional assays showed that luteolin is a selective antagonist of the vasopressin receptor V1AR (IC50 = 19.49 ± 6.32 µM) and the dopamine D4 receptor (IC50 = 39.59 ± 1.46 µM). Molecular docking showed the tight binding of luteolin with a low binding score and the high stability of the luteolin-receptor complex, corroborating its functional effect. Thus, hMAO-A, hD4R, and hV1AR are prime targets of luteolin and potential alternatives for the management of neurodegenerative diseases.

Bromophenols from Symphyocladia latiuscula Target Human Monoamine Oxidase and Dopaminergic Receptors for the Management of Neurodegenerative Diseases.

Progressive degeneration of dopaminergic neurons in the substantia nigra is the characteristic feature of Parkinson's disease (PD) and the severity accelerates with aging. Therefore, improving dopamine level or dopamine receptor signaling is a standard approach for PD treatment. Herein, our results demonstrate that bromophenols 2,3,6-tribromo-4,5-dihydroxybenzyl alcohol (1), 2,3,6-tribromo-4,5-dihydroxybenzyl methyl ether (2), and bis-(2,3,6-tribromo-4,5-dihydroxybenzyl) ether (3) from red alga Symphyocladia latiuscula are moderate-selective human monoamine oxidase-A inhibitors and good dopamine D3/D4 receptor agonists. Bromophenol 3 showed a promising D4R agonist effect with a low micromole 50% effective concentration (EC50) value. All of the test ligands were docked against a three-dimensional (3D) model of hD3R and hD4R, and the result demonstrated strong binding through interaction with prime interacting residues-Asp110, Cys114, and His349 on hD3R and Asp115 and Cys119 on hD4R. Overall, the results demonstrated natural bromophenols, especially 1 and 3, from Symphyocladia latiuscula as multitarget ligands for neuroprotection, especially in PD and schizophrenia.

New role for crinamine as a potent, safe and selective inhibitor of human monoamine oxidase B: In vitro and in silico pharmacology and modeling.

ETHNOPHARMACOLOGICAL RELEVANCE: The development of selective inhibitors of monoamine oxidase B (MAO-B) has been essential in treating Parkinson's disease. However, the apparent hepatotoxicity and drug-drug interactions of current inhibitors accentuate the need for the development of novel pharmacotherapies. Crossyne guttata (L.) D. & U. Müll-Doblies is used frequently by Rastafarian bush doctors to treat alcoholism, a disorder which is also accentuated by MAO. OBJECTIVE: The study sought to isolate, identify and characterise the biologically active constituents of C. guttata based on their ability to inhibit the MAO enzymes. MATERIALS AND METHODS: Column chromatography was used to isolate the biologically active alkaloids of C. guttata. The ability of the alkaloids to inhibit the biotransformation of 4-aminoantipyrine by the MAO enzymes was evaluated in vitro. In silico docking was conducted using AutoDock Vina server while the pharmacokinetic properties of the compounds were evaluated using SwissADME. RESULTS: Chromatographic separation of an ethanolic fraction of C. guttata yielded the alkaloids crinamine 1 and epibuphanisine 2. 1 and 2 along with structurally related alkaloids haemanthamine 3 and haemanthidine 4 were evaluated for their ability to inhibit the action of isozymes of MAO in vitro. Alkaloids effected submicromolar IC50 values against MAO-B, the most potent of which being crinamine 1 (0.014 µM) > haemanthidine 4 (0.017 µM) > epibuphanisine 2 (0.039 µM) > haemanthamine 3 (0.112 µM). Binding energies of the alkaloids correlated well with their inhibitory potential with crinamine displaying the best binding efficacy and binding energy score with MAO-B. DISCUSSION AND CONCLUSION: Crinamine and epibuphanisine exhibited potent and selective inhibitory activity towards MAO-B. After comprehensive in silico investigations encompassing robust molecular docking analysis, the drug-like attributes and safety of the alkaloids suggest the crinamine is a potentially safe drug for human application.

Novel Diels-Alder Type Adducts from Morus alba Root Bark Targeting Human Monoamine Oxidase and Dopaminergic Receptors for the Management of Neurodegenerative Diseases.

In this study, we delineate the human monoamine oxidase (hMAO) inhibitory potential of natural Diels-Alder type adducts, mulberrofuran G (1), kuwanon G (2), and albanol B (3), from Morus alba root bark to characterize their role in Parkinson's disease (PD) and depression, focusing on their ability to modulate dopaminergic receptors (D1R, D2LR, D3R, and D4R). In hMAO-A inhibition, 1-3 showed mild effects (50% inhibitory concentration (IC50): 54‒114 µM). However, 1 displayed moderate inhibition of the hMAO-B isozyme (IC50: 18.14 ± 1.06 µM) followed by mild inhibition by 2 (IC50: 57.71 ± 2.12 µM) and 3 (IC50: 90.59 ± 1.72 µM). Our kinetic study characterized the inhibition mode, and the in silico docking predicted that the moderate inhibitor 1 would have the lowest binding energy. Similarly, cell-based G protein-coupled receptors (GPCR) functional assays in vector-transfected cells expressing dopamine (DA) receptors characterized 1-3 as D1R/D2LR antagonists and D3R/D4R agonists. The half-maximum effective concentration (EC50) of 1-3 on DA D3R/D4R was 15.13/17.19, 20.18/21.05, and 12.63/‒ µM, respectively. Similarly, 1-3 inhibited 50% of the DA response on D1R/D2LR by 6.13/2.41, 16.48/31.22, and 7.16/18.42 µM, respectively. A computational study revealed low binding energy for the test ligands. Interactions with residues Asp110, Val111, Tyr365, and Phe345 at the D3R receptor and Asp115 and His414 at the D4R receptor explain the high agonist effect. Likewise, Asp187 at D1R and Asp114 at D2LR play a crucial role in the antagonist effects of the ligand binding. Our overall results depict 1-3 from M. alba root bark as good inhibitors of hMAO and potent modulators of DA function as D1R/D2LR antagonists and D3R/D4R agonists. These active constituents in M. alba deserve in-depth study for their potential to manage neurodegenerative disorders (NDs), particularly PD and psychosis.

Spondias mombim L. (Anacardiaceae): Chemical fingerprints, inhibitory activities, and molecular docking on key enzymes relevant to erectile dysfunction and Alzheimer's diseases.

Due to the exceptional wide range in biochemical activities of natural plant products, Spondias mombim L. are attaining a new height because they present great prospects for drug advancement. This research was designed to analyze the pharmaceutical properties of S. mombim L. ethyl acetate fraction (SMEAF) on key enzymes relevant to erectile and cognitive dysfunction. SMEAF inhibitory activities of the specified enzymes were determined spectrophotometrically. Chemical profile of SMEAF were assessed by HPLC/MS analysis. Thereafter, molecular docking of the studied enzymes with chlorogenic acid, lutein, and zeaxanthin were carried out using PATCHDOCK. SMEAF had remarkable enzyme inhibitory effects against phosphodiesterase-5 (PDE-5), arginase, angiotensin I-converting enzyme (ACE), cholinesterase, monoamine oxidase A (MAO), ecto-5' nucleotidase (E-NTDase), tyrosinase, and stimulated sodium-potassium ATPase (Na+/K+-ATPase) activities. HPLC/MS analysis revealed that phenolics and carotenoids were major components in these fraction notably, chlorogenic acid, lutein, and zeaxanthin. Our results suggested that SMEAF could be explored as phytopharmaceuticals. PRACTICAL APPLICATIONS: Spondias mombim L. are cooked as green vegetable with enormous medicinal value probably due to its polyphenols with potent antioxidant activity. Furthermore, the leaves could also be useful for therapeutic purposes against erectile dysfunction and central nervous system disorders.

Discovery, synthesis, biological evaluation and molecular docking study of (R)-5-methylmellein and its analogs as selective monoamine oxidase A inhibitors.

(R)-5-Methylmellein (5-MM), the major ingredient in the fermented mycelia of the medicinal fungus Xylaria nigripes (called Wuling Shen in Chinese)¸ was found to be a selective inhibitor against monoamine oxidase A (MAO-A) and might play an important role in the clinical usage of this edible fungus as an anti-depressive traditional Chinese medicine (TCM). Based on the discovery and hypothesis, a variety of (R)-5-MM analogs were synthesized and evaluated in vitro against two monoamine oxidase isoforms (MAO-A and MAO-B). Most synthetic analogs showed selective inhibition of MAO-A with IC50 values ranging from 0.06 to 29 µM, and compound 13aR is the most potent analog with high selectivity (IC50, MAO-A: 0.06 µM; MAO-B: >50 µM). Interestingly, the enzyme kinetics study of 13aR indicated that this ligand seemed to bind in the MAO-A active site according to so-called "tight-binding inhibition" mode. The molecular docking study of 13aR was thereafter performed in order to rationalize the obtained biological results.

Ligand fishing of anti-neurodegenerative components from Lonicera japonica using magnetic nanoparticles immobilised with monoamine oxidase B.

In this work, monoamine oxidase B was immobilised onto magnetic nanoparticles to prepare a new type of affinity solid-phase extraction adsorbent, which was used to extract the possible anti-neurodegenerative components from the Lonicera japonica flower extracts. Coupled with high-performance liquid chromatography with mass spectrometry, two monoamine oxidase B ligands were fished-out and identified as isochlorogenic acid A and isochlorogenic acid C, which were found to be inhibitors of the enzyme for the first time, with similar half maximal inhibitory concentration values of 29.05 ± 0.49 and 29.77 ± 1.03 µM, respectively. Furthermore, equilibrium-dialysis dissociation assay of enzyme-inhibitor complex showed that both compounds have reversible binding patterns to monoamine oxidase B, and kinetic analysis demonstrated that they were mixed-type inhibitors for monoamine oxidase B, with Ki and Kis values of 9.55 and 37.24 µM for isochlorogenic acid A, 9.53 and 35.50 µM for isochlorogenic acid C, respectively. The results indicated that isochlorogenic acid A and isochlorogenic acid C were the major active components responsible for the anti-degenerative activity of the flowers of L. japonica, while magnetic nanoparticles immobilised monoamine oxidase B could serve as an efficient solid-phase extraction adsorbent to specifically extract monoamine oxidase B inhibitors from complex herbal extracts.

Docking Screens for Dual Inhibitors of Disparate Drug Targets for Parkinson's Disease.

Modulation of multiple biological targets with a single drug can lead to synergistic therapeutic effects and has been demonstrated to be essential for efficient treatment of CNS disorders. However, rational design of compounds that interact with several targets is very challenging. Here, we demonstrate that structure-based virtual screening can guide the discovery of multi-target ligands of unrelated proteins relevant for Parkinson's disease. A library with 5.4 million molecules was docked to crystal structures of the A2A adenosine receptor (A2AAR) and monoamine oxidase B (MAO-B). Twenty-four compounds that were among the highest ranked for both binding sites were evaluated experimentally, resulting in the discovery of four dual-target ligands. The most potent compound was an A2AAR antagonist with nanomolar affinity ( Ki = 19 nM) and inhibited MAO-B with an IC50 of 100 nM. Optimization guided by the predicted binding modes led to the identification of a second potent dual-target scaffold. The two discovered scaffolds were shown to counteract 6-hydroxydopamine-induced neurotoxicity in dopaminergic neuronal-like SH-SY5Y cells. Structure-based screening can hence be used to identify ligands with specific polypharmacological profiles, providing new avenues for drug development against complex diseases.

Inhibition of human monoamine oxidase A and B by flavonoids isolated from two Algerian medicinal plants.

BACKGROUND: Monoamine oxidases (MAOs) are outer mitochondrial membrane flavoenzymes. They catalyze the oxidative deamination of a variety of neurotransmitters. MAO-A and MAO-B may be considered as targets for inhibitors to treat neurodegenerative diseases and depression and for managing symptoms associated with Parkinson's and Alzheimer's diseases. PURPOSE: The objective was to evaluate the inhibitory effect of Hypericum afrum and Cytisus villosus against MAO-A and B and to isolate the compounds responsible for the MAO-inhibitory activity. METHODS: The inhibitory effect of extracts and purified constituents of H. afrum and C. villosus were investigated in vitro using recombinant human MAO-A and B, and through bioassay-guided fractionation of ethyl acetate fractions of areal parts of the two plants collected in northeastern Algeria. In addition, computational protein-ligand docking and molecular dynamics simulations were carried out to explain the MAO binding at the molecular level. RESULTS: The ethyl acetate (EtOAc) fractions of H. afrum and C. villosus showed the highest MAO inhibition activity against MAO A and B with IC50 values of 3.37 µg/ml and 13.50 µg/ml as well as 5.62 and 1.87 µg/ml, respectively. Bioassay-guided fractionation of the EtOAc fractions resulted in the purification and identification of the known flavonoids quercetin, myricetin, genistein and chrysin as the principal MAO-inhibitory constituents. Their structures were established by extensive 1 and 2D NMR studies and mass spectrometry. Quercetin, myricetin and chrysin showed potent inhibitory activity towards MAO-A with IC50 values of 1.52, 9.93 and 0.25 µM, respectively, while genistein more efficiently inhibited MAO-B (IC50 value: 0.65 µM). The kinetics of the inhibition and the study of dialysis dissociation of the complex of quercetin and myricetin and the isoenzyme MAO-A showed competitive and mixed inhibition, respectively. Both compounds showed reversible binding. Molecular docking experiments and molecular dynamics simulations allowed to estimate the binding poses and to identify the most important residues involved in the selective recognition of molecules in the MAOs enzymatic clefts. CONCLUSION: Quercetin and myricetin isolated from H. afrum together with genistein and chrysin isolated from C. villosus have been identified as potent MAO-A and -B inhibitors. H. afrum and C. villosus have properties indicative of potential neuroprotective ability and may be new candidates for selective MAO-A and B inhibitors.

Preliminary studies of berberine and its semi-synthetic derivatives as a promising class of multi-target anti-parkinson agents.

Parkinson's disease (PD) is a neurodegenerative disorder bearing motor and nonmotor symptoms. The treatment today is symptomatical rather than preventive or curative and this leaves the field open for the search of both novel molecular targets and drug candidates. Interference with α-synuclein fibrillation, monoamine oxidase (MAO) inhibition, modulation of adenosine receptors and the inhibition of specific phosphodiesterase (PDE) isoforms are some of the currently pursued strategies. We synthesised and studied some semi-synthetic berberine derivatives using a set of in silico tools. We evaluated their drug-likeness and tested the compounds against a set of target proteins involved in the onset or progression of PD, with a particular attention to MAO-B. Preliminary in vitro assay on MAO-B confirmed our in silico predictions.

Assessment of Enzyme Inhibition: A Review with Examples from the Development of Monoamine Oxidase and Cholinesterase Inhibitory Drugs.

The actions of many drugs involve enzyme inhibition. This is exemplified by the inhibitors of monoamine oxidases (MAO) and the cholinsterases (ChE) that have been used for several pharmacological purposes. This review describes key principles and approaches for the reliable determination of enzyme activities and inhibition as well as some of the methods that are in current use for such studies with these two enzymes. Their applicability and potential pitfalls arising from their inappropriate use are discussed. Since inhibitor potency is frequently assessed in terms of the quantity necessary to give 50% inhibition (the IC50 value), the relationships between this and the mode of inhibition is also considered, in terms of the misleading information that it may provide. Incorporation of more than one functionality into the same molecule to give a multi-target-directed ligands (MTDLs) requires careful assessment to ensure that the specific target effects are not significantly altered and that the kinetic behavior remains as favourable with the MTDL as it does with the individual components. Such factors will be considered in terms of recently developed MTDLs that combine MAO and ChE inhibitory functions.

The Benzopyrone Biochanin-A as a reversible, competitive, and selective monoamine oxidase B inhibitor.

BACKGROUND: Monoamine oxidase-B (MAO-B) inhibitors are widely used in the treatment of Parkinson's disease. They increase vital monoamine neurotransmitters in the brain. However, there is a need for safer natural reversible MAO inhibitors with MAO-B selectivity. Our previous studies showed that Psoralea corylifolia seeds (PCS) extract contains compounds that inhibit monoamine oxidase-B. METHODS: In this study, six of PCS constituents sharing a benzopyrone structure were investigated. The compounds Biochanin-A (BIO-A), isopsoralen, 6-prenylnaringenin, neobavaisoflavone, psoralen, and psoralidin, were tested for their ability to inhibit recombinant human MAO-A and B (hMAO-A and hMAO-B) isozymes. The ability of these compounds to inhibit MAO-A and MAO-B were compared to that of PCS ethanolic extract (PCSEE) using spectrophotometric assays and confirmed by luminescence assays. The highly potent and selective MAO-B inhibitor, BIO-A, was further investigated for both isozymes reversibility and enzyme kinetics. Molecular docking studies were used to predict the bioactive conformation and molecular interactions of BIO-A with both isozymes. RESULTS: The data obtained indicate that benzopyrones inhibited hMAO-A and hMAO-B with different degrees as confirmed with the luminescence assay. BIO-A inhibited hMAO-B with high potency and selectivity in the present study (IC50 = 0.003 µg/mL) and showing 38-fold more selectivity than PCSEE (hMAO-B IC50 = 3.03 µg/mL, 17-fold selectivity) without affecting hydrogen peroxide. Furthermore, BIO-A reversibly and competitively inhibited both hMAOs with significantly lower inhibitory constant (Ki) in hMAO-B (3.8 nM) than hMAO-A (99.3 nM). Our docking studies indicated that the H-bonds and hydrophobic interactions at the human MAO-A and MAO-B active sites contributed to the reversibility and selectivity of BIO-A. CONCLUSIONS: The data obtained indicate that BIO-A is a potent, reversible and selective MAO-B inhibitor and may be recommended for further investigation in its possible use in the therapeutic management of Parkinson's and Alzheimer's diseases.

Silver nanoparticle exposure in pregnant rats increases gene expression of tyrosine hydroxylase and monoamine oxidase in offspring brain.

CONTEXT: Maternal exposure to silver nanoparticles (AgNPs) affects neurobehavioral reflexes and spatial memory formation in offspring. Although the transmission of AgNPs into the brain has been reported, its toxic effect on dopamine metabolism in the brain of offspring has not been studied so far. OBJECTIVE: The aim of the present study was to investigate the expression levels of tyrosine hydroxylase (TH) and monoamine oxidase A (MAO-A) genes in the brain of offspring exposed in utero to various concentrations of AgNPs. MATERIALS AND METHODS: Time mated pregnant adult rats were assigned into three groups including control, low dose of AgNPs (0.2 mg/kg) and high dose of AgNPs (2 mg/kg). AgNPs were subcutaneously (SC) injected at days of 1, 4, 7, 10, 13, 16 and 19 of pregnancy. Gene expression of TH and MAO-A was analyzed in the brain of offspring (male and female) at days of 1, 7, 14 and 21 after birth. RESULTS: Administration of AgNPs to pregnant rats in a time- and dose-dependent manner increased the expression levels of TH in the brain of male and female pups at all tested days after birth (p < 0.05). AgNPs had stimulatory effect on MAO-A mRNA expression in pups only at the age of 7 and 14. Female pups showed the higher level of TH and MAO-A compared to that in male pups (p < 0.001). DISCUSSION AND CONCLUSIONS: Results obtained here demonstrated that the exposure of pregnant rats to AgNPs increases the expression of genes involved in dopamine metabolism in the brain of offspring.

Monoamine Oxidase Inhibitory Activity of Biflavonoids from Branches of Garcinia gardneriana (Clusiaceae).

Garcinia gardneriana is chemically characterized by the presence of biflavonoids. Taking into account that flavonoids are able to inhibit monoamine oxidase (MAO) activity, in the present study, the chemical composition of the branches' extract of the plant is described for the first time and the MAO inhibitory . activity of the isolated biflavonoids was evaluated. Based on spectroscopic and spectrometric data, it was possible to identify volkesiflavone, morelloflavone (1), Gb-2a (2) and Gb-2a-7-Ο-glucoside (3) in the ethyl acetate fraction from ethanol extract of the branches. Compounds 1-3 were evaluated in vitro and demonstrated the capacity to inhibit MAO-A activity with an IC50 ranging from 5.05 to 10.7 µM, and from 20.7 to 66.2 µM for MAO-B. These inhibitions corroborate with previous IC50 obtained for monomeric flavonoids, with a higher selectivity for MAO-A isoform. The obtained results indicate that biflavonoids might be promising structures for the identification of new MAO inhibitory compounds.

Computational Drug Target Screening through Protein Interaction Profiles.

The development of computational methods to discover novel drug-target interactions on a large scale is of great interest. We propose a new method for virtual screening based on protein interaction profile similarity to discover new targets for molecules, including existing drugs. We calculated Target Interaction Profile Fingerprints (TIPFs) based on ChEMBL database to evaluate drug similarity and generated new putative compound-target candidates from the non-intersecting targets in each pair of compounds. A set of drugs was further studied in monoamine oxidase B (MAO-B) and cyclooxygenase-1 (COX-1) enzyme through molecular docking and experimental assays. The drug ethoxzolamide and the natural compound piperlongumine, present in Piper longum L, showed hMAO-B activity with IC50 values of 25 and 65 µM respectively. Five candidates, including lapatinib, SB-202190, RO-316233, GW786460X and indirubin-3'-monoxime were tested against human COX-1. Compounds SB-202190 and RO-316233 showed a IC50 in hCOX-1 of 24 and 25 µM respectively (similar range as potent inhibitors such as diclofenac and indomethacin in the same experimental conditions). Lapatinib and indirubin-3'-monoxime showed moderate hCOX-1 activity (19.5% and 28% of enzyme inhibition at 25 µM respectively). Our modeling constitutes a multi-target predictor for large scale virtual screening with potential in lead discovery, repositioning and drug safety.

Exploration of a Library of 3,4-(Methylenedioxy)aniline-Derived Semicarbazones as Dual Inhibitors of Monoamine Oxidase and Acetylcholinesterase: Design, Synthesis, and Evaluation.

A library of 3,4-(methylenedioxy)aniline-derived semicarbazones was designed, synthesized, and evaluated as monoamine oxidase (MAO) and acetylcholinesterase (AChE) inhibitors for the treatment of neurodegenerative diseases. Most of the new compounds selectively inhibited MAO-B and AChE, with IC50 values in the micro- or nanomolar ranges. Compound 16, 1-(2,6-dichlorobenzylidene)-4-(benzo[1,3]dioxol-5-yl)semicarbazide presented a balanced multifunctional profile of MAO-A (IC50 =4.52±0.032 µm), MAO-B (IC50 =0.059±0.002 µm), and AChE (IC50 =0.0087±0.0002 µm) inhibition without neurotoxicity. Kinetic studies revealed that compound 16 exhibits competitive and reversible inhibition against MAO-A and MAO-B, and mixed-type inhibition against AChE. Molecular docking studies further revealed insight into the possible interactions within the enzyme-inhibitor complexes. The most active compounds were found to interact with the enzymes through hydrogen bonding and hydrophobic interactions. Additionally, in silico molecular properties and ADME properties of the synthesized compounds were calculated to explore their drug-like characteristics.