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João KG, Videira RA, Paiva-Martins F, Valentão P, Pereira DM, Andrade PB. Homarine Alkyl Ester Derivatives as Promising Acetylcholinesterase Inhibitors. ChemMedChem 2021; 16:3315-3325. [PMID: 34342141 DOI: 10.1002/cmdc.202100265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 07/13/2021] [Indexed: 11/08/2022]
Abstract
Reversible acetylcholinesterase (AChE) inhibitors are key therapeutic tools to modulate the cholinergic connectivity compromised in several degenerative pathologies. In this work, four alkyl esters of homarine were synthesized and screened by using Electrophorus electricus AChE and rat brain AChE-rich fraction. Results showed that all homarine alkyl esters are able to inhibit AChE by a competitive inhibition mode. The effectiveness of AChE inhibition increases with the alkyl side chain length of the homarine esters, being HO-C16 (IC50 =7.57±3.32 μM and Ki =18.96±2.28 μM) the most potent inhibitor. The fluorescence quenching studies confirmed that HO-C16 is the compound with higher selectivity and affinity for the tryptophan residues in the catalytic active site of AChE. Preliminary cell viability studies showed that homarine esters display no toxicity for human neuronal SH-SY5Y cells. Thus, the long-chain homarine esters emerge as new anti-cholinesterase agents, with potential to be considered for therapeutic applications development.
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Affiliation(s)
- Karen G João
- REQUIMTE/LAQV, Laboratório de Farmacognosia, Departamento de Química, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira, N° 228, 4050-313, Porto, Portugal
| | - Romeu A Videira
- REQUIMTE/LAQV, Laboratório de Farmacognosia, Departamento de Química, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira, N° 228, 4050-313, Porto, Portugal
| | - Fátima Paiva-Martins
- REQUIMTE/LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre 1021/1055, 4169-007, Porto, Portugal
| | - Patrícia Valentão
- REQUIMTE/LAQV, Laboratório de Farmacognosia, Departamento de Química, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira, N° 228, 4050-313, Porto, Portugal
| | - David M Pereira
- REQUIMTE/LAQV, Laboratório de Farmacognosia, Departamento de Química, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira, N° 228, 4050-313, Porto, Portugal
| | - Paula B Andrade
- REQUIMTE/LAQV, Laboratório de Farmacognosia, Departamento de Química, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira, N° 228, 4050-313, Porto, Portugal
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Potency determinations of acetylcholinesterase inhibitors using Ellman’s reaction-based assay in screening: Effect of assay variants. Anal Biochem 2011; 408:166-8. [DOI: 10.1016/j.ab.2010.09.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Revised: 09/09/2010] [Accepted: 09/13/2010] [Indexed: 11/18/2022]
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Ahmed M, Rocha JBT, Corrêa M, Mazzanti CM, Zanin RF, Morsch ALB, Morsch VM, Schetinger MRC. Inhibition of two different cholinesterases by tacrine. Chem Biol Interact 2006; 162:165-71. [PMID: 16860785 DOI: 10.1016/j.cbi.2006.06.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2006] [Revised: 06/10/2006] [Accepted: 06/12/2006] [Indexed: 10/24/2022]
Abstract
Kinetic parameters of the effect of tacrine as a cholinesterase inhibitor have been studied in two different sources: snake venom (Bungarus sindanus) acetylcholinesterase (AChE) and human serum butyrylcholinesterase (BChE). Tacrine inhibited both venom acetylcholinesterase (AChE) as well as human serum butyrylcholinesterase (BChE) in a concentration-dependent manner. Kinetic studies indicated that the nature of inhibition was mixed for both enzymes, i.e. Km values increase and Vmax decrease with the increase of the tacrine concentration. The calculated IC50 for snake venom and for human serum were 31 and 25.6 nM, respectively. Ki was observed to be 13 nM for venom acetylcholinesterase (AChE) and 12 nM for serum butyrylcholinesterase (BChE). KI (constant of AChE-ASCh-tacrine complex into AChE-ASCh complex and tacrine) was estimated to be 20 nM for venom and 10 nM for serum butyrylcholinesterase (BChE), while the gammaKm (dissociation constant of AChE-ASCh-tacrine complex into AChE-tacrine complex and ASCh) were 0.086 and 0.147 mM for snake venom AChE and serum BChE, respectively. The present results suggest that this therapeutic agent used for the treatment of Alzheimer's disease can also be considered an inhibitor of snake venom and human serum butyrylcholinesterase. Values of Ki and KI show that tacrine had more affinity with these enzymes as compared with other cholinesterases from the literature.
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Affiliation(s)
- Mushtaq Ahmed
- Departamento de Química, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS, Brazil
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Kamal MA, Greig NH, Alhomida AS, Al-Jafari AA. Kinetics of human acetylcholinesterase inhibition by the novel experimental Alzheimer therapeutic agent, tolserine. Biochem Pharmacol 2000; 60:561-70. [PMID: 10874131 DOI: 10.1016/s0006-2952(00)00330-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Characterization of the kinetic parameters of tolserine, a novel acetylcholinesterase (AChE) inhibitor of potential in the therapy of Alzheimer's disease, to inhibit purified human erythrocyte AChE was undertaken for the first time. An IC(50) value was estimated by three methods. Its mean value was found to be 8.13 nM, whereas the IC(100) was observed to be 25.5 nM as calculated by single graphical method. The Michaelis-Menten constant (K(m)) for the hydrolysis of the substrate acetylthiocholine iodide was found to be 0.08 mM. Dixon as well as Lineweaver-Burk plots and their secondary replots indicated that the nature of the inhibition was of the partial non-competitive type. The value of K(i) was estimated as 4.69 nM by the primary and secondary replots of the Dixon as well as secondary replots of the Lineweaver-Burk plot. Four new kinetic constants were also investigated by polynomial regression analysis of the relationship between the apparent K(i) (K(Iapp)) and substrate concentration, which may open new avenues for the kinetic study of the inhibition of several enzymes by a wide variety of inhibitors in vitro. Tolserine proved to be a highly potent inhibitor of human AChE compared to its structural analogues physostigmine and phenserine.
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Affiliation(s)
- M A Kamal
- Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
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Kamal MA, Al-jafari AA. Kinetic constants for the inhibition of camel retinal acetylcholinesterase by the carbamate insecticide lannate. J Biochem Mol Toxicol 2000; 13:41-6. [PMID: 9890446 DOI: 10.1002/(sici)1099-0461(1999)13:1<41::aid-jbt5>3.0.co;2-f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We have designed this study to determine various kinetic parameters of camel retinal membrane-bound acetylcholinesterase (AChE; EC 3.1.1.7) inhibition by carbamate insecticide lannate [methyl N-[[(methylamino)carbonyl]oxy] ethanimidothioate]. All these kinetic constants were derived by simple graphical methods. The value of kinetic parameters was estimated as follows: 0.061 microM)(-1), 1.14 (microM)(-1), 0.216 microM, 0.016 min(-1), 0.0741 (gammaM min)(-1) 0.746 microM, and 4.42 microM for velocity constant (Kv), new inhibition constant (Knic), dissociation constant (Kd), carbamylation rate constant (k2c), overall carbamylation rate constant (k'2), 50% inhibition constant (K150), and 99% inhibition constant (K199), respectively. These unique methods may be used to estimate such kinetic parameters for time-dependent inhibition of enzymes by variety of chemicals, insecticides, herbicides, and drugs.
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Affiliation(s)
- M A Kamal
- Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
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Alhomida AS, Al-Rajhi AA, Kamal MA, Al-Jafari AA. Kinetic analysis of the toxicological effect of tacrine (Cognex) on human retinal acetylcholinesterase activity. Toxicology 2000; 147:33-9. [PMID: 10837930 DOI: 10.1016/s0300-483x(00)00177-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
For the first time, kinetic parameters of the effect of tacrine, an anti-cholinesterase inhibitor of therapeutic potential in Alzheimer's disease has been studied on human retinal acetyl-cholinesterase (AChE). Tacrine inhibited the AChE activity in a concentration dependent manner, the IC(50) being about 45 nM. The Michaelis-Menten constant (K(m)) for the hydrolysis of acetylthiocholine iodide was found to be 0.120 mM and this value was increased by 4-52.8% in the presence of tacrine. V(max) was observed to be 2.23 micromol/h per mg protein for the control system, while it was decreased by 14.73-56.25% in the tacrine treated systems. Dixon as well as Lineweaver-Burk plots and their secondary replots indicated that the nature of the inhibition was of the mixed type, i. e. a combination of competitive and noncompetitive inhibition. The values of K(i) and K(I) were estimated to be as 37.76 and 64.36 nM, respectively.
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Affiliation(s)
- A S Alhomida
- Department of Biochemistry, College of Science, King Saud University, PO Box 2455, 11451, Riyadh, Saudi Arabia
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Kamal MA, Nasim FH, Al-Jafari AA. Human erythrocyte acetylcholinesterase inhibition by cis-diamminediaquaplatinum (II): a novel kinetic approach. Cancer Lett 1999; 138:115-9. [PMID: 10378782 DOI: 10.1016/s0304-3835(98)00385-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The present work addresses the analyses of some novel kinetic parameters (k(t), K(v), t50, K(ir), t(c), m(c), IC50, IC99 and Ki) of human erythrocyte membrane-bound acetylcholinesterase (AChE, EC 3.1.1.7) inhibition by cis-diamminediaquaplatinum II (PDC). PDC is under a clinical trial for use as an antineoplastic drug. The authors recently reported that PDC and cisplatin have the ability to inhibit AChE activity in vitro. Therefore this study was designed to determine the estimation of time constant (k(t)), velocity constant (K(v)), 50% inhibition time (t50), inhibition rate constant (K(ir)), transition concentration (t(c)), meeting concentration (m(c)), 50% inhibition (IC50), 99% inhibition (IC99) and inhibition constant (Ki) by novel methods. The details are described in the text.
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Affiliation(s)
- M A Kamal
- Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
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Al-Jafari AA, Al-Khwyter F, Kamal MA. Kinetics of the inhibition of acetylcholinesterase in camel retina by cisplatin. Cancer Lett 1998; 128:79-86. [PMID: 9652796 DOI: 10.1016/s0304-3835(98)00054-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The inhibitory effect of cisplatin (CDDP) on camel retina acetylcholinesterase (AChE) was characterized. The CDDP effect was independent of the time of incubation with AChE before the addition of substrate, indicative of reversible inhibition. Moreover, dilution data prove that CDDP is a reversible inhibitor of camel retina AChE. Cisplatin inhibited AChE activity of camel retina in a concentration- and time-dependent manner, the IC50 values being 5.32 and 0.196 mM at 5 min and 24 h incubation times, respectively. The IC50 has dual components, i.e. directly proportional and inversely proportional to 0-1.5 h and 1.5-24 h incubation periods, respectively. The Michaelis-Menten constant (Km) for the hydrolysis of acetylthiocholine iodide (ASCh) was found to be 0.0796 mM and Vmax was 0.668 micromol/min/mg protein. Kmapp and Vmaxapp both decreased as the CDDP concentration increased. Dixon as well as Lineweaver-Burk plots and their secondary replots indicated that the nature of the inhibition was of the pure uncompetitive type. The value of Ki was estimated as 0.811 mM by the primary and secondary replots of the Lineweaver-Burk and Dixon plots. Kiapp decreased while Vmaxiapp increased after increasing the ASCh concentration.
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Affiliation(s)
- A A Al-Jafari
- Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia.
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Valenti P, Rampa A, Bisi A, Andrisano V, Cavrini V, Fin L, Buriani A, Giusti P. Acetylcholinesterase inhibition by tacrine analogues. Bioorg Med Chem Lett 1997. [DOI: 10.1016/s0960-894x(97)10025-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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