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1.
Food Chem ; 327: 127045, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32464460

RESUMO

In this study, the inhibitory potentials of food originated 34 phenolic acids, and flavonoid compounds were screened against acetylcholinesterase, butyrylcholinesterase, urease, and tyrosinase enzymes. All compounds included in this study exhibited high antioxidant activity with an ignorable cytotoxic activity. In general, they also showed poor anti-urease and anti-tyrosinase activities. Compounds in aglycone form (quercetin, myricetin, chrysin, and luteolin) showed strong anticholinesterase activities. No relation was observed between the tested bioactivities except from the case that aglycone compounds exhibited a strong positive relationship between antioxidant activities and anticholinesterase activity. Interestingly, there was a relation between the molecular weights of aglycone compounds and their anticholinesterase activities. The study showed that flavonoids with molecular mass of 250-320 g/mol have high potential of anticholinesterase activities and are valuable for future experiments on animals and humans. Potential inhibitory effects of these molecules on target proteins were investigated using docking and molecular dynamics calculations.


Assuntos
Inibidores da Colinesterase/química , Flavonoides/química , Hidroxibenzoatos/química , Plantas Comestíveis/química , Acetilcolinesterase/química , Acetilcolinesterase/metabolismo , Animais , Antioxidantes/química , Sítios de Ligação , Domínio Catalítico , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Inibidores da Colinesterase/metabolismo , Inibidores da Colinesterase/farmacologia , Flavonoides/metabolismo , Flavonoides/farmacologia , Humanos , Hidroxibenzoatos/metabolismo , Simulação de Acoplamento Molecular , Monofenol Mono-Oxigenase/antagonistas & inibidores , Monofenol Mono-Oxigenase/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/química , Plantas Comestíveis/metabolismo
2.
Food Chem ; 324: 126889, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32353659

RESUMO

Pesticides have been extensively applied worldwide to protect crops from worms and insects; however, the continuous use of pesticides affects ecosystems, agricultural product safety, nontarget organisms, and human health. In this paper, we report a highly sensitive biosensor for the determination of pesticides based on tin sulfide (SnS2) and chitosan (CHIT) nanocomposites decorated with a unique British housefly acetylcholinesterase (AChE). The hydrothermally synthesized nano-SnS2 mixed with chitosan solution (CHIT-SnS2) was drop-casted onto a glassy carbon electrode (GCE). Subsequently, the British housefly AChE was immobilized on the CHIT/SnS2-coated GCE that was then employed for pesticide detection. The developed biosensor showed an ultra-high sensitivity and wide linear detection range from 0.02 nM to 20000 nM with a detection limit of 0.02 nM for the detection of chlorpyrifos as the model pesticide. Furthermore, the AChE/CHIT-SnS2/GCE exhibited acceptable storage stability, good reproducibility, and selectivity.


Assuntos
Acetilcolinesterase/metabolismo , Técnicas Biossensoriais/métodos , Quitosana/química , Moscas Domésticas/enzimologia , Compostos Organofosforados/análise , Sulfetos/química , Compostos de Estanho/química , Acetilcolinesterase/química , Animais , Carbono/química , Clorpirifos/análise , Técnicas Eletroquímicas , Eletrodos , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Limite de Detecção , Nanocompostos/química , Praguicidas/análise , Reprodutibilidade dos Testes
3.
Chemosphere ; 255: 127007, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32416396

RESUMO

Chiral organophosphorus pollutants are existed ubiquitously in the ecological environment, but the enantioselective toxicities of these nerve agents to humans and their molecular bases have not been fully elucidated. Using experimental and computational approaches, this story was to explore the neurotoxic response process of the target acetylcholinesterase (AChE) to chiral phenthoate and further decipher the microscopic mechanism of such toxicological effect at the enantiomeric level. The results showed that the toxic reaction of AChE with chiral phenthoate exhibited significant enantioselectivity, and (R)-phenthoate (K=1.486 × 105 M-1) has a bioaffinity for the nerve enzyme nearly three times that of (S)-phenthoate (K=4.503 × 104 M-1). Dynamic research outcomes interpreted the wet experiments, and the inherent conformational flexibility of the target enzyme has a great influence on the enantioselective neurotoxicological action processes, especially reflected in the conformational changes of the three key loop regions (i.e. residues His-447, Gly-448, and Tyr-449; residues Gly-122, Phe-123, and Tyr-124; and residues Thr-75, Leu-76, and Tyr-77) around the reaction patch. This was supported by the quantitative results of conformational studies derived from circular dichroism spectroscopy (α-helix: 34.7%→30.2%/31.6%; ß-sheet: 23.6%→19.5%/20.7%; turn: 19.2%→22.4%/21.9%; and random coil: 22.5%→27.9%/25.8%). Meanwhile, via analyzing the modes of toxic action and free energies, we can find that (R)-phenthoate has a strong inhibitory effect on the enzymatic activity of AChE, as compared with (S)-phenthoate, and electrostatic energy (-23.79/-17.77 kJ mol-1) played a critical role in toxicological reactions. These points were the underlying causes of chiral phenthoate displaying different degrees of enantioselective neurotoxicity.


Assuntos
Acetilcolinesterase/química , Poluentes Ambientais/química , Poluentes Ambientais/toxicidade , Síndromes Neurotóxicas/etiologia , Compostos Organotiofosforados/química , Compostos Organotiofosforados/toxicidade , Dicroísmo Circular , Humanos , Modelos Teóricos , Simulação de Dinâmica Molecular , Fenômenos Físicos , Estrutura Secundária de Proteína , Estereoisomerismo
4.
J Agric Food Chem ; 68(10): 3140-3148, 2020 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-32053361

RESUMO

3-O-Cinnamoylepicatechin (1) was synthesized along with four flavoalkaloids, (-)-6-(5‴S)-N-ethyl-2-pyrrolidinone-3-O-cinnamoylepicatechin (2), (-)-6-(5‴R)-N-ethyl-2-pyrrolidinone-3-O-cinnamoylepicatechin (3), (-)-8-(5‴S)-N-ethyl-2-pyrrolidinone-3-O-cinnamoylepicatechin (4), and (-)-8-(5‴R)-N-ethyl-2-pyrrolidinone-3-O-cinnamoylepicatechin (5) via esterification of epicatechin followed by phenolic Mannich reaction of 1 with theanine in the presence of heat. The new compounds 1-5 were detected in leaves of three tea cultivars, Fuding-Dabai, Huangjingui, and Zimudan with the help of ultra-performance liquid chromatography hyphenated with a photodiode array detector and electrospray ionization high-resolution mass spectrometry (UPLC-PDA-ESI-HRMS), suggesting that they are naturally occurring in tea leaves. The structures of the novel natural products were characterized by one- and two-dimensional nuclear magnetic resonance (1D and 2D NMR) and mass spectroscopy. Compounds 1-5 were then evaluated for their acetylcholinesterase (AChE) inhibitory effect (IC50 = 0.12-1.02 µM). The availability of the synthesized epicatechin derivatives 1-5 via a synthetic route enabled the first unequivocal identification of these derivatives as tea secondary metabolites and made it possible to determine their content in the tea material as well as the diverse bioactivities.


Assuntos
Alcaloides/química , Camellia sinensis/química , Inibidores da Colinesterase/química , Extratos Vegetais/química , Acetilcolinesterase/química , Cromatografia Líquida de Alta Pressão , Folhas de Planta/química , Espectrometria de Massas por Ionização por Electrospray
5.
Biochim Biophys Acta Biomembr ; 1862(5): 183188, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-31930963

RESUMO

Langmuir films prepared from bovine erythrocyte membranes (LFBEM) were studied and transferred to alkylated glasses (Langmuir-Blodgett films, LBBEM) in order to assess the effects of membrane molecular packing on Bovine Erythrocyte Acetylcholinesterase (BEA) catalytic activity. Surface pressure (π) vs Area isotherms showed three 2D-transitions at ~7, ~18 and ~44 mN/m and a collapse pressure at πc = 49 mN/m. The 0-12-0 mN/m compression-decompression cycles resulted reversible while those 0-40-0 mN/m exhibited a significant hysteresis. Taken together, EFM, BAM and AFM images and the stability of the film after 3C-D cycles, we can suggest that over the air-water interface as well as over the silanized glass substrate the surface is mostly covered by a monolayer with a few particles dispersed. Acetylthiocholine hydrolysis was assayed with BEA in bovine erythrocyte membrane suspensions (SBEM) and in LBBEM packed at 10 (LBBEM,10) and 35 mN/m (LBBEM,35), which gave the following kinetic parameters: Vmax = 3.41 ± 0.15, 0.021 ± 0.002 and 0.030 ± 0.003 nmol.min-1·µg prot-1 and KM = 0.11 ± 0.02, 0.047 ± 0.017 and 0.026 ± 0.017 mM, respectively. Although from SBEM to LBBEM we lost active enzyme, the catalytic efficiency (Vmax/KM) increased ~750 times. Eugenol and 1,8-cineol inhibited BEA catalytic activity in LBBEM,35. Our results demonstrate the transmission of information between the membrane and the environment within the subphase immediately below the membrane, where anchored proteins are hosted. This was reflected by the membrane packing-induced modulation of BEA catalytic activity. Furthermore, LBBEM provides a proof of concept for the development of biosensors to screen new green pesticides acting through BEA interaction.


Assuntos
Acetilcolinesterase/metabolismo , Membrana Eritrocítica/química , Membrana Eritrocítica/metabolismo , Acetilcolinesterase/química , Acetilcolinesterase/fisiologia , Adsorção/fisiologia , Animais , Catálise , Bovinos , Membrana Eritrocítica/fisiologia , Hidrólise , Cinética , Microscopia de Força Atômica/métodos , Estudo de Prova de Conceito , Propriedades de Superfície , Água/química
6.
J Chromatogr A ; 1609: 460506, 2020 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-31526637

RESUMO

A high-performance liquid chromatography-mass spectrometry technique hyphenated on-line with an immobilized enzyme reactor (IMER) was developed by the use of 3 known acetylcholinesterase (AChE) inhibitors (galanthamine, huperzine A and tacrine). This bioanalytical device allows qualitative comparison of the inhibitory strengths of AChE inhibitors. The AChE inhibitory strengths were evaluated and compared by the corresponding acetylcholine peak areas (mass signal) obtained after a chromatographic separation and the elution through the IMER. Only one injection of the analytes is needed to get this comparative analysis. This bioanalytical device was then applied to the extract of a natural plant, Lycoris radiata, which is known to contain AChE inhibitors such as galanthamine and lycoramine. Aside from the demonstration of the inhibitory activity of the two known AChE inhibitors, the AChE inhibitory activity of another compound (dihydro-latifaliumin C) was revealed. This is the first report describing the AChE inhibitory activity of this compound.


Assuntos
Inibidores da Colinesterase/análise , Cromatografia Líquida de Alta Pressão/métodos , Enzimas Imobilizadas/análise , Espectrometria de Massas/métodos , Sistemas On-Line , Acetilcolina/análise , Acetilcolinesterase/química , Reatores Biológicos , Galantamina/análise , Limite de Detecção , Lycoris/química , Extratos Vegetais/química , Reprodutibilidade dos Testes
7.
Food Chem ; 309: 125766, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31718836

RESUMO

This study aimed to identify by UPLC-PDA-Q/TOF-MS and quantify by UPLC-PDA phenolic compounds (26 flavonols and 2 phenolic acids) and carotenoids (16) from berries of different cultivars of Hippophaë rhamnoides and determine correlations between these variables and in vitro anticholinergic and on-line antioxidant potential. Isorhamnetin derivatives presented over 65% of total flavonols, but quercetin and kaempferol derivatives were also determined. Carotenes accounted for 19 to 47%, xanthophylls 16 to 81% of total carotenoids. Pearson's correlations between AChE and BuChE inhibition and phenolic acid content were low (r = 0.388 and 0.355), moderate for carotenoids (0.504 and 0.437) and high for flavonols (0.851 and 0.614). The PCA biplot showed the highest correlation between anticholinergic activity and all-trans-ß-cryptoxanthin, quercetin-3-O-glucoside, isorhamnetin-3-O-(2-rhamnosyl)glucoside, kaempferol-3-O-hexoside-7-O-rhamnoside, isorhamnetin-3-O-(6-rhamnosyl)hexoside, isorhamnetin-3-O-rutinoside, and isorhamnetin-3-O-glucoside concentrations. The results obtained can be used to identify sea buckthorn cultivars, develop crops and production, and design functional products rich in flavonols and carotenoids with anticholinergic properties.


Assuntos
Antioxidantes/química , Carotenoides/análise , Inibidores da Colinesterase/análise , Cromatografia Líquida de Alta Pressão/métodos , Hippophae/química , Fenóis/análise , Acetilcolinesterase/química , Acetilcolinesterase/metabolismo , Butirilcolinesterase/química , Butirilcolinesterase/metabolismo , Inibidores da Colinesterase/química , Flavonóis/análise , Frutas/química , Frutas/metabolismo , Hippophae/metabolismo , Análise de Componente Principal
8.
Food Chem ; 307: 125523, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31639572

RESUMO

Lutein is a bioactive found in dark leafy vegetables that may be used as a nutraceutical agent in foodstuff and an inhibitor of key enzymes of the human body such as those involved in the cholinergic system. However, its high hydrophobicity leads to low bioavailability and must be overcome if lutein is to be added in foods. The objective of this study was to evaluate the influence of nanoencapsulated lutein in the activity of the acetylcholinesterase enzyme. The in vitro study was carried out using water in order to evaluate the impact of encapsulation on the hydrophilicity of lutein. In vitro assays showed that lutein, both free and nanoencapsulated, presented a mixed-type inhibition behavior, and encapsulated lutein was able to inhibit acetylcholinesterase activity even in an aqueous medium. Inhibition was also showed by the in silico docking results which show that lutein interacted with the pocket region of the enzyme.


Assuntos
Acetilcolinesterase/metabolismo , Cápsulas/química , Luteína/química , Simulação de Acoplamento Molecular , Nanopartículas/química , Acetilcolinesterase/química , Sítios de Ligação , Suplementos Nutricionais/análise , Humanos , Interações Hidrofóbicas e Hidrofílicas , Cinética , Luteína/metabolismo , Estrutura Terciária de Proteína
9.
Biosens Bioelectron ; 148: 111796, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31665672

RESUMO

We present a new strategy of Acetylcholinesterease (AchE) immobilization on graphene field-effect transistors (gFETs) for building up Acetylcholine sensors. This method is based on the electrosynthesis of an amino moiety-bearing polymer layer on the graphene channel. The film of the copolymer poly(3-amino-benzylamine-co-aniline) (PABA) does not only provide the suitable electrostatic charge and non-denaturing environment for enzyme immobilization, but it also improves the pH sensitivity of the gFETs (from 40.8 to 56.3 µA/pH unit), probably due to its wider effective pKa distribution. The local pH changes caused by the enzyme-catalyzed hydrolysis produce a shift in the Dirac point of the gFETs to more negative values, which are evidenced as differences in the gFET conductivity and thereby constituted the signal transduction mechanism of the modified transistors. In this way, the constructed biosensors showed a LOD of 2.3 µM and were able to monitor Ach in the range from 5 to 1000 µM in a flow configuration. Moreover, they showed a sensitivity of -26.6 ±â€¯0.7 µA/Ach decade and also exhibited a very low RSD of 2.6%, revealing good device-to-device reproducibility. The biosensors revealed an excellent selectivity to interferences known to be present in the extracellular milieu, and the response to Ach was recovered by 97.5% after the whole set of interferences injected. Finally, the biosensors showed a fast response time, with an average value of 130 s and a good long-term response.


Assuntos
Acetilcolina/análise , Técnicas Biossensoriais/instrumentação , Grafite/química , Polímeros/química , Transistores Eletrônicos , Acetilcolinesterase/química , Compostos de Anilina/química , Benzilaminas/química , Enzimas Imobilizadas/química , Desenho de Equipamento , Oxirredução , Polimerização , Água/análise
10.
Biochim Biophys Acta Proteins Proteom ; 1868(1): 140270, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31518689

RESUMO

A new spectrofluorimetric method more sensitive than the Ellman method was developed for determination of both acetylcholinesterase and butyrylcholinesterase activity and for kinetic analysis of these enzymes and their mutants. Two selected mutants of human butyrylcholinesterase (E197Q and E197G) were included in this work. As for the Ellman's method, substrates are thiocholine esters, but the chromogenic reagent, DTNB (dithio-bisnitro benzoic acid) is replaced by a fluorogenic probe, "Calbiochem Probe IV", (3-(7-Hydroxy-2-oxo-2H-chromen-3-ylcarbamoyl)acrylic acid methylester). Compared to the classical Ellman's method, the sensitivity of this new spectrofluorimetric assay is 2 orders of magnitude higher. The method allows measurement of activity in media containing <10-11 M of cholinesterase active sites at low substrate concentrations, either under first order conditions, [S] << Km, or under conditions where kinetics obeys the Michaelis-Menten model, i.e. at [S] < 1 mM for wild-type enzymes. The method adapted to titration plate reader assays is suitable for clinical and toxicological routine analyses, for high throughput screening of novel cholinesterase mutants and screening of inhibitor libraries of pharmacological interest.


Assuntos
Acetilcolinesterase/química , Butirilcolinesterase/química , Acetilcolinesterase/genética , Acetiltiocolina/análogos & derivados , Acetiltiocolina/química , Butirilcolinesterase/genética , Butiriltiocolina/química , Catálise , Humanos , Cinética , Simulação de Acoplamento Molecular , Mutação , Espectrometria de Fluorescência
11.
Toxicol Lett ; 321: 83-89, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31863869

RESUMO

Acetylcholinesterase (AChE) is a pivotal enzyme in neurotransmission. Its inhibition leads to cholinergic crises and could ultimately result in death. A related enzyme, butyrylcholinesterase (BChE), may act in the CNS as a co-regulator in terminating nerve impulses and is a natural plasma scavenger upon exposure to organophosphate (OP) nerve agents that irreversibly inhibit both enzymes. With the aim of improving reactivation of cholinesterases phosphylated by nerve agents sarin, VX, cyclosarin, and tabun, ten phenyltetrahydroisoquinoline (PIQ) aldoximes were synthesized by Huisgen 1,3 dipolar cycloaddition between alkyne- and azide-building blocks. The PIQ moiety may serve as a peripheral site anchor positioning the aldoxime moiety at the AChE active site. In terms of evaluated dissociation inhibition constants, the aldoximes could be characterized as high-affinity ligands. Nevertheless, high binding affinity of these oximes to AChE or its phosphylated conjugates did not assure rapid and selective AChE reactivation. Rather, potential reactivators of phosphylated BChE, with its enlarged acyl pocket, were identified, especially in case of cyclosarin, where the reactivation rates of the lead reactivator was 100- and 6-times that of 2-PAM and HI-6, respectively. Nevertheless, the return of the enzyme activity was affected by the nerve agent conjugated to catalytic serine, which highlights the lack of the universality of reactivators with respect to both the target enzyme and OP structure.


Assuntos
Butirilcolinesterase/metabolismo , Reativadores da Colinesterase/farmacologia , Agentes Neurotóxicos/toxicidade , Intoxicação por Organofosfatos/tratamento farmacológico , Oximas/farmacologia , Acetilcolinesterase/química , Acetilcolinesterase/metabolismo , Butirilcolinesterase/química , Inibidores da Colinesterase/toxicidade , Reativadores da Colinesterase/síntese química , Ativação Enzimática , Proteínas Ligadas por GPI/agonistas , Proteínas Ligadas por GPI/antagonistas & inibidores , Proteínas Ligadas por GPI/química , Proteínas Ligadas por GPI/metabolismo , Humanos , Cinética , Intoxicação por Organofosfatos/enzimologia , Organofosfatos/toxicidade , Compostos Organofosforados/toxicidade , Compostos Organotiofosforados/toxicidade , Oximas/síntese química , Conformação Proteica , Sarina/toxicidade , Relação Estrutura-Atividade
12.
Molecules ; 24(24)2019 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-31847089

RESUMO

Alkaloids having acetylcholinesterase (AChE) inhibitory activity are commonly found in traditional Chinese medicine (TCM); for example, berberine from Coptis chinensis, galantamine from Lycoris radiata, and huperzine A from Huperzia serrata. In practice of TCM, Stephaniae Tetrandrae Radix (STR) is often combined with Coptidis Rhizoma (CR) or Phellodendri Chinensis Cortex (PCC) as paired herbs during clinical application. Fangchinoline from STR and coptisine and/or berberine from CR and/or PCC are active alkaloids in inhibiting AChE. The traditional usage of paired herbs suggests the synergistic effect of fangchinoline-coptisine or fangchinoline-berberine pairing in AChE inhibition. HPLC was applied to identify the main components in herbal extracts of STR, CR, and PCC, and the AChE inhibition of their main components was determined by Ellman assay. The synergism of herb combination and active component combination was calculated by median-effect principle. Molecular docking was applied to investigate the underlying binding mechanisms of the active components with the AChE protein. It was found that fangchinoline showed AChE inhibitory potency; furthermore, fangchinoline-coptisine/berberine pairs (at ratios of 1:5, 1:2, 1:1, and 2:1) synergistically inhibited AChE; the combination index (CI) at different ratios was less than one when Fa = 0.5, suggesting synergistic inhibition of AChE. Furthermore, the molecular docking simulation supported this enzymatic inhibition. Therefore, fangchinoline-coptisine/berberine pairs, or their parental herbal mixtures, may potentially be developed as a possible therapeutic strategy for Alzheimer's patients.


Assuntos
Acetilcolinesterase/metabolismo , Alcaloides/farmacologia , Inibidores da Colinesterase/farmacologia , Medicamentos de Ervas Chinesas/química , Phellodendron/química , Stephania tetrandra/química , Acetilcolinesterase/química , Alcaloides/química , Benzilisoquinolinas/química , Benzilisoquinolinas/farmacologia , Berberina/análogos & derivados , Berberina/química , Berberina/farmacologia , Inibidores da Colinesterase/química , Combinação de Medicamentos , Sinergismo Farmacológico , Medicina Tradicional Chinesa , Simulação de Acoplamento Molecular , Extratos Vegetais/química
13.
Int J Mol Sci ; 21(1)2019 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-31861333

RESUMO

A series of 44 hybrid compounds that included in their structure tetrahydroquinoline (THQ) and isoxazole/isoxazoline moieties were synthesized through the 1,3-dipolar cycloaddition reaction (1,3-DC) from the corresponding N-allyl/propargyl THQs, previously obtained via cationic Povarov reaction. In vitro cholinergic enzymes inhibition potential of all compounds was tested. Enzyme inhibition assays showed that some hybrids exhibited significant potency to inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Especially, the hybrid compound 5n presented the more effective inhibition against AChE (4.24 µM) with an acceptable selectivity index versus BChE (SI: 5.19), while compound 6aa exhibited the greatest inhibition activity on BChE (3.97 µM) and a significant selectivity index against AChE (SI: 0.04). Kinetic studies were carried out for compounds with greater inhibitory activity of cholinesterases. Structure-activity relationships of the molecular hybrids were analyzed, through computational models using a molecular cross-docking algorithm and Molecular Mechanics/Generalized Born Surface Area (MM/GBSA) binding free energy approach, which indicated a good correlation between the experimental inhibition values and the predicted free binding energy.


Assuntos
Inibidores da Colinesterase/química , Inibidores da Colinesterase/farmacologia , Isoxazóis/química , Quinolinas/química , Acetilcolinesterase/química , Sítios de Ligação , Domínio Catalítico , Técnicas de Química Sintética , Inibidores da Colinesterase/síntese química , Ativação Enzimática/efeitos dos fármacos , Humanos , Ligação de Hidrogênio , Cinética , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Estrutura Molecular , Ligação Proteica , Relação Estrutura-Atividade
14.
Nutrients ; 11(11)2019 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-31703329

RESUMO

One of the major neurodegenerative features of Alzheimer's disease (AD) is the presence of neurotoxic amyloid plaques composed of amyloid beta peptide (Aß). ß-Secretase (BACE1) and acetylcholinesterase (AChE), which promote Aß fibril formation, have become attractive therapeutic targets for AD. P-glycoprotein (P-gp), the major efflux pump of the blood-brain barrier (BBB), plays a critical role in limiting therapeutic molecules. In pursuit of discovering a natural anti-AD candidate, the bioactivity, physicochemical, drug-likeness, and molecular docking properties of baicalein, a major compound from Scutellaria baicalensis, was investigated. Baicalein exhibited strong BACE1 and AChE inhibitory properties (IC50 23.71 ± 1.91 µM and 45.95 ± 3.44 µM, respectively) and reacted in non-competitive and competitive manners with substrates, respectively. in Silico docking analysis was in full agreement with the in vitro results, demonstrating that the compound exhibited powerful binding interaction with target enzymes. Particularly, three continuous hydroxyl groups on the A ring demonstrated strong H-bond binding properties. It is also noteworthy that baicalein complied with all requirements of Lipinski's rule of five by its optimal physicochemical properties for both oral bioavailability and blood-brain barrier permeability. Overall, the present study strongly demonstrated the possibility of baicalein having in vivo pharmacological efficacy for specific targets in the prevention and/or treatment of AD.


Assuntos
Acetilcolinesterase , Secretases da Proteína Precursora do Amiloide , Ácido Aspártico Endopeptidases , Inibidores da Colinesterase , Flavanonas , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/química , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Acetilcolinesterase/química , Acetilcolinesterase/metabolismo , Doença de Alzheimer , Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Secretases da Proteína Precursora do Amiloide/química , Secretases da Proteína Precursora do Amiloide/metabolismo , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Ácido Aspártico Endopeptidases/química , Ácido Aspártico Endopeptidases/metabolismo , Inibidores da Colinesterase/química , Inibidores da Colinesterase/metabolismo , Inibidores da Colinesterase/farmacologia , Flavanonas/química , Flavanonas/metabolismo , Flavanonas/farmacologia , Humanos , Simulação de Acoplamento Molecular , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Scutellaria baicalensis
15.
Int J Mol Sci ; 20(21)2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31683761

RESUMO

A series of novel 2-carbo-substituted 5-oxo-5H-furo[3,2-g]chromene-6-carbaldehydes and their 6-(4-trifluoromethyl)phenylhydrazono derivatives have been prepared and evaluated for biological activity against the human acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). The most active compounds from each series were, in turn, evaluated against the following enzyme targets involved in Alzheimer's disease, ß-secretase (BACE-1) and lipoxygenase-15 (LOX-15), as well as for anti-oxidant potential. Based on the in vitro results of ChE and ß-secretase inhibition, the kinetic studies were conducted to determine the mode of inhibition by these compounds. 2-(4-Methoxyphenyl)-5-oxo-5H-furo[3,2-g]chromene-6-carbaldehyde (2f), which exhibited significant inhibitory effect against all these enzymes was also evaluated for activity against the human lipoxygenase-5 (LOX-5). The experimental results were complemented with molecular docking into the active sites of these enzymes. Compound 2f was also found to be cytotoxic against the breast cancer MCF-7 cell line.


Assuntos
Doença de Alzheimer/prevenção & controle , Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Inibidores da Colinesterase/química , Simulação de Acoplamento Molecular , Acetilcolinesterase/química , Acetilcolinesterase/metabolismo , Doença de Alzheimer/enzimologia , Secretases da Proteína Precursora do Amiloide/química , Secretases da Proteína Precursora do Amiloide/metabolismo , Araquidonato 5-Lipoxigenase/química , Araquidonato 5-Lipoxigenase/metabolismo , Butirilcolinesterase/química , Butirilcolinesterase/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Inibidores da Colinesterase/metabolismo , Inibidores da Colinesterase/farmacologia , Humanos , Cinética , Inibidores de Lipoxigenase/química , Inibidores de Lipoxigenase/metabolismo , Inibidores de Lipoxigenase/farmacologia , Células MCF-7 , Estrutura Molecular , Relação Estrutura-Atividade
16.
BMC Complement Altern Med ; 19(1): 296, 2019 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-31694704

RESUMO

BACKGROUND: Bergenia ciliata is a medicinal plant used for the treatment of diarrhea, vomiting, fever, cough, diabetes, cancer, pulmonary disorders and wound healing. METHODS: In this study, Bergenia ciliata crude extract, subfractions, and isolated compounds were evaluated for their antioxidant and anticholinesterase potential. The free radical scavenging capacities of the extracts determined using DPPH and ABTS assays. The anticholinesterase potentials were determined using acetylcholine esterase and butyryl choline esterase enzymes. To determine the phytochemical composition, the extracts were subjected to HPLC analysis and silica gel column isolation. Based on HPLC fingerprinting results, the ethyl acetate fraction was found to have more bioactive compounds and was therefore subjected to silica gel column isolation. As a result, three compounds; pyrogallol, rutin, and morin were isolated in the pure state. The structures of the isolated compounds were elucidated using spectroscopic techniques like 1H-NMR, IR and UV-Visible. RESULTS: The crude extract showed maximum anticholinesterase (acetylcholinesterase = 90.22 ± 1.15% and butyrylcholinesterase = 88.22 ± 0.71%) and free radical scavenging (87.37 ± 2.45 and 83.50 ± 0.70% respectively against DPPH and ABTS radicals) potentials. The total phenolic contents (expressed as equivalent of gallic acid; mgGAE/g) were higher in ethyl acetate fraction (80.96 ± 1.74) followed by crude extract (70.65 ± 0.86) while the flavonoid contents (expressed as quercetin equivalent; mgQE/g) and were higher in crude extract (88.40 ± 1.12) followed by n-butanol fraction (60.10 ± 1.86). The isolated bioactive compounds pyrogallol, rutin, and morin were found active against ABTS and DPPH free radicals. Amongst them, pyrogallol was more active against both free radicals. Reasonable anticholinesterase activities were recorded for pyrogallol against selected enzymes. CONCLUSION: The extracts and isolated compounds showed antioxidant and acetylcholinesterase inhibitory potentials. It was concluded that this plant could be helpful in the treatment of oxidative stress and neurological disorders if used in the form of extracts.


Assuntos
Antioxidantes/química , Inibidores da Colinesterase/química , Extratos Vegetais/química , Saxifragaceae/química , Acetilcolinesterase/química , Antioxidantes/isolamento & purificação , Butirilcolinesterase/química , Inibidores da Colinesterase/isolamento & purificação , Flavonoides/química , Flavonoides/isolamento & purificação , Fenóis/química , Fenóis/isolamento & purificação , Extratos Vegetais/isolamento & purificação , Rizoma/química
17.
J Agric Food Chem ; 67(43): 11986-11993, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31593461

RESUMO

Global Natural Product Social feature-based networking was applied to follow the phytochemicals, including nine flavonoid glycosides, six catechins, and three flavonols in Huangjinya green tea. Further, a new 8-O-4'-type neolignan glycoside, camellignanoside A (1), and 15 known compounds (2-16) were isolated through a variety of column chromatographies, and the structure was elucidated extensively by ultra performance liquid chromatography-quadrupole-time-of-flight-tandem mass spectrometry, 1H and 13C nuclear magnetic resonance, heteronuclear single-quantum correlation, heteronuclear multiple-bond correlation, 1H-1H correlation spectroscopy, rotating frame nuclear Overhauser effect spectroscopy, and Nuclear Overhauser effect spectroscopy, and circular dichroism spectroscopies. Compounds 1 and 2 showed acetylcolinesterase inhibition activity, with IC50 = 0.75 and 0.18 µM, respectively.


Assuntos
Camellia sinensis/química , Inibidores da Colinesterase/química , Glicosídeos/química , Lignanas/química , Extratos Vegetais/química , Acetilcolinesterase/química , Cromatografia Líquida de Alta Pressão , Humanos , Cinética , Estrutura Molecular , Folhas de Planta/química , Espectrometria de Massas em Tandem , Chá/química
18.
Chem Biol Interact ; 314: 108845, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31593690

RESUMO

Phenazines, naturally produced by bacteria and archaeal Methanosarcina species are nitrogen-containing tricyclic molecules with antibiotic, antitumoral, and antiparasitic activities. Phenazines are used as electron acceptors-donors in wide range of fields including environmental biosensors. In this study, the inhibitory effects of a synthetic phenazine dye, methylene violet 3RAX (also known as diethyl safranine) on human erythrocyte AChE and human plasma BChE were tested and also its inhibitory mechanisms for both enzymes were studied in detail. Kinetic analyses showed that methylene violet 3RAX acts as a hyperbolic noncompetitive inhibitor of AChE with Ki value of 1.58 ±â€¯0.36 µM; α = 1; ß = 0.12 ±â€¯0.0003. On the other hand, it caused linear competitive inhibition of BChE with Ki value of 0.51 ±â€¯0.006 µM; α = ∞. In conclusion, methylene violet 3RAX which is a highly effective inhibitor of both human AChE and human BChE with Ki values in low micromolar range may be a promising candidate for the treatment of Alzheimer's disease.


Assuntos
Acetilcolinesterase/metabolismo , Butirilcolinesterase/metabolismo , Inibidores da Colinesterase/química , Fenotiazinas/química , Acetilcolinesterase/química , Butirilcolinesterase/química , Inibidores da Colinesterase/metabolismo , Humanos , Cinética , Fenotiazinas/metabolismo
19.
Food Funct ; 10(10): 6915-6926, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31588440

RESUMO

Morus species, commonly known as mulberry, is widely distributed in China. The mulberry tree is a high-value plant in agriculture. Morus australis is one of the major Morus species growing in Northern China. However, the biological properties of the main constituents of M. australis roots were not well studied. In the present study, through extensive chromatographic and spectral analysis, 12 phenolic compounds were isolated and identified from the M. australis roots. Compounds 1, 2, 8, 9 and 12 were isolated from M. australis roots for the first time. Antitumor activities of these polyphenols were studied on the A549 cell line. Compounds 1, 5 and 6 exhibited cytotoxicity on A549 cells and induced apoptosis in A549 cells via the intrinsic mitochondrial pathway. They also mediated inhibition of autophagic flux contributed cell death via the PI3k/Akt/mTOR pathway. In order to explore more potential bioactivities of these isolates, α-glucosidase, acetylcholinesterase and tyrosinase inhibitory activities were studied, and the results demonstrated that the inhibitory activity of these polyphenols on enzymes was not defined by their basic structural skeletons, but by the substituted position.


Assuntos
Morus/química , Extratos Vegetais/química , Raízes de Plantas/química , Polifenóis/química , Células A549/efeitos dos fármacos , Acetilcolinesterase/química , Acetilcolinesterase/isolamento & purificação , Apoptose/efeitos dos fármacos , Movimento Celular , Proliferação de Células/efeitos dos fármacos , China , Humanos , Concentração Inibidora 50 , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Fenóis/análise , Fosfatidilinositol 3-Quinases , Polifenóis/farmacologia , alfa-Glucosidases/química , alfa-Glucosidases/isolamento & purificação
20.
J Chem Phys ; 151(12): 125103, 2019 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-31575200

RESUMO

This article reports on a frequency domain analysis of quasielastic neutron scattering spectra from free and Huperzine-A-inhibited human acetylcholinesterase, extending a recent time domain analysis of the same experimental data [M. Saouessi et al., J. Chem. Phys. 150, 161104 (2019)]. An important technical point here is the construction of a semianalytical model for the resolution-broadened dynamic structure factor that can be fitted to the experimental spectra. We find comparable parameters as in our previous study and demonstrate that our model is sensitive to subpercent changes in the experimental data, which are caused by reversible binding of the inhibitor Huperzine A.


Assuntos
Acetilcolinesterase/química , Alcaloides/química , Inibidores da Colinesterase/química , Sesquiterpenos/química , Alcaloides/farmacologia , Inibidores da Colinesterase/farmacologia , Humanos , Difração de Nêutrons , Domínios Proteicos , Sesquiterpenos/farmacologia
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