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Abstract
The reaction between the antimalarial drug artesunate (ATS) and ferriprotoporphyrin_(IX) (FPIX) in the presence of glutathione (GSH) has been monitored by nuclear magnetic resonance (NMR) spectroscopy. By following the disappearance of resonances of protons near the endoperoxide group in ATS, the rate at which the drug is activated can be directly measured. In an aqueous medium, the rate of ATS activation is limited by the rate of reduction of the FPIX Fe(III) center by GSH. The reaction is observed to slow dramatically in the presence of other heme binding antimalarial drugs. These findings explain the long observed antagonism between artemisinin derivatives and quinoline-based drugs. This discovery suggests that combination therapy that involves artemisinin or any of its derivatives and a quinoline-based drug may be compromised.
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Affiliation(s)
- Laura Heller
- Dept. of Chemistry, Georgetown University, 37 and O Streets, Washington, DC
| | - Paul D Roepe
- Dept. of Chemistry, Georgetown University, 37 and O Streets, Washington, DC.,Dept, of Biochemistry and Cellular & Molecular Biology, Georgetown University, 37 and O Streets, Washington, DC.,Center for Infectious Disease, Georgetown University, 37 and O Streets, Washington, DC
| | - Angel C de Dios
- Dept. of Chemistry, Georgetown University, 37 and O Streets, Washington, DC.,Center for Infectious Disease, Georgetown University, 37 and O Streets, Washington, DC
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2
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Heller LE, Roepe PD. Artemisinin-Based Antimalarial Drug Therapy: Molecular Pharmacology and Evolving Resistance. Trop Med Infect Dis 2019; 4:tropicalmed4020089. [PMID: 31167396 PMCID: PMC6631165 DOI: 10.3390/tropicalmed4020089] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 05/21/2019] [Accepted: 05/24/2019] [Indexed: 12/27/2022] Open
Abstract
The molecular pharmacology of artemisinin (ART)-based antimalarial drugs is incompletely understood. Clinically, these drugs are used in combination with longer lasting partner drugs in several different artemisinin combination therapies (ACTs). ACTs are currently the standard of care against Plasmodium falciparum malaria across much of the world. A harbinger of emerging artemisinin resistance (ARTR), known as the delayed clearance phenotype (DCP), has been well documented in South East Asia (SEA) and is beginning to affect the efficacy of some ACTs. Though several genetic mutations have been associated with ARTR/DCP, a molecular mechanism remains elusive. This paper summarizes our current understanding of ART molecular pharmacology and hypotheses for ARTR/DCP.
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Affiliation(s)
- Laura E Heller
- Departments of Chemistry and of Biochemistry and Cellular and Molecular Biology, Georgetown University, 37th and O Streets NW, Washington, DC 20057, USA.
| | - Paul D Roepe
- Departments of Chemistry and of Biochemistry and Cellular and Molecular Biology, Georgetown University, 37th and O Streets NW, Washington, DC 20057, USA.
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3
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Chan WC, Wai Chan DH, Lee KW, Tin WS, Wong HN, Haynes RK. Evaluation and optimization of synthetic routes from dihydroartemisinin to the alkylamino-artemisinins artemiside and artemisone: A test of N-glycosylation methodologies on a lipophilic peroxide. Tetrahedron 2018. [DOI: 10.1016/j.tet.2018.04.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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4
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Griesbeck AG, Bräutigam M, Kleczka M, Raabe A. Synthetic Approaches to Mono- and Bicyclic Perortho-Esters with a Central 1,2,4-Trioxane Ring as the Privileged Lead Structure in Antimalarial and Antitumor-Active Peroxides and Clarification of the Peroxide Relevance. Molecules 2017; 22:molecules22010119. [PMID: 28085079 PMCID: PMC6155645 DOI: 10.3390/molecules22010119] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 01/04/2017] [Accepted: 01/06/2017] [Indexed: 12/21/2022] Open
Abstract
The synthesis of 4-styryl-substituted 2,3,8-trioxabicyclo[3.3.1]nonanes, peroxides with the core structure of the bioactive 1,2,4-trioxane ring, was conducted by a multistep route starting from the aryl methyl ketones 1a–1c. Condensation and reduction/oxidation delivered enals 4a–4c that were coupled with ethyl acetate and reduced to the 1,3-diol substrates 6a–6c. Highly diastereoselective photooxygenation delivered the hydroperoxides 7a–7c and subsequent PPTS (pyridinium-p-toluenesulfonic acid)-catalyzed peroxyacetalization with alkyl triorthoacetates gave the cyclic peroxides 8a–8e. These compounds in general show only moderate antimalarial activities. In order to extend the repertoire of cyclic peroxide structure, we aimed for the synthesis of spiro-perorthocarbonates from orthoester condensation of β-hydroxy hydroperoxide 9 but could only realize the monocyclic perorthocarbonate 10. That the central peroxide moiety is the key structural motif in anticancer active GST (glutathione S-transferase)-inhibitors was elucidated by the synthesis of a 1,3-dioxane 15—with a similar substitution pattern as the pharmacologically active peroxide 11—via a singlet oxygen ene route from the homoallylic alcohol 12.
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Affiliation(s)
- Axel G Griesbeck
- Department of Chemistry, University of Cologne, Greinstr. 4, 50939 Köln, Germany.
| | - Maria Bräutigam
- Department of Chemistry, University of Cologne, Greinstr. 4, 50939 Köln, Germany.
| | - Margarethe Kleczka
- Department of Chemistry, University of Cologne, Greinstr. 4, 50939 Köln, Germany.
| | - Angela Raabe
- Department of Chemistry, University of Cologne, Greinstr. 4, 50939 Köln, Germany.
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Griesbeck AG, El-Idreesy TT. En Route to Improved Antimalarial Peroxides Following the Natural Role Model Artemisinin. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.200600193] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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6
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Haynes RK, Cheu KW, Chan HW, Wong HN, Li KY, Tang MMK, Chen MJ, Guo ZF, Guo ZH, Sinniah K, Witte AB, Coghi P, Monti D. Interactions between artemisinins and other antimalarial drugs in relation to the cofactor model--a unifying proposal for drug action. ChemMedChem 2012; 7:2204-26. [PMID: 23112085 DOI: 10.1002/cmdc.201200383] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 09/30/2012] [Indexed: 01/14/2023]
Abstract
Artemisinins are proposed to act in the malaria parasite cytosol by oxidizing dihydroflavin cofactors of redox-active flavoenzymes, and under aerobic conditions by inducing their autoxidation. Perturbation of redox homeostasis coupled with the generation of reactive oxygen species (ROS) ensues. Ascorbic acid-methylene blue (MB), N-benzyl-1,4-dihydronicotinamide (BNAH)-MB, BNAH-lumiflavine, BNAH-riboflavin (RF), and NADPH-FAD-E. coli flavin reductase (Fre) systems at pH 7.4 generate leucomethylene blue (LMB) and reduced flavins that are rapidly oxidized in situ by artemisinins. These oxidations are inhibited by the 4-aminoquinolines piperaquine (PPQ), chloroquine (CQ), and others. In contrast, the arylmethanols lumefantrine, mefloquine (MFQ), and quinine (QN) have little or no effect. Inhibition correlates with the antagonism exerted by 4-aminoquinolines on the antimalarial activities of MB, RF, and artemisinins. Lack of inhibition correlates with the additivity/synergism between the arylmethanols and artemisinins. We propose association via π complex formation between the 4-aminoquinolines and LMB or the dihydroflavins; this hinders hydride transfer from the reduced conjugates to the artemisinins. The arylmethanols have a decreased tendency to form π complexes, and so exert no effect. The parallel between chemical reactivity and antagonism or additivity/synergism draws attention to the mechanism of action of all drugs described herein. CQ and QN inhibit the formation of hemozoin in the parasite digestive vacuole (DV). The buildup of heme-Fe(III) results in an enhanced efflux from the DV into the cytosol. In addition, the lipophilic heme-Fe(III) complexes of CQ and QN that form in the DV are proposed to diffuse across the DV membrane. At the higher pH of the cytosol, the complexes decompose to liberate heme-Fe(III) . The quinoline or arylmethanol reenters the DV, and so transfers more heme-Fe(III) out of the DV. In this way, the 4-aminoquinolines and arylmethanols exert antimalarial activities by enhancing heme-Fe(III) and thence free Fe(III) concentrations in the cytosol. The iron species enter into redox cycles through reduction of Fe(III) to Fe(II) largely mediated by reduced flavin cofactors and likely also by NAD(P)H-Fre. Generation of ROS through oxidation of Fe(II) by oxygen will also result. The cytotoxicities of artemisinins are thereby reinforced by the iron. Other aspects of drug action are emphasized. In the cytosol or DV, association by π complex formation between pairs of lipophilic drugs must adversely influence the pharmacokinetics of each drug. This explains the antagonism between PPQ and MFQ, for example. The basis for the antimalarial activity of RF mirrors that of MB, wherein it participates in redox cycling that involves flavoenzymes or Fre, resulting in attrition of NAD(P)H. The generation of ROS by artemisinins and ensuing Fenton chemistry accommodate the ability of artemisinins to induce membrane damage and to affect the parasite SERCA PfATP6 Ca(2+) transporter. Thus, the effect exerted by artemisinins is more likely a downstream event involving ROS that will also be modulated by mutations in PfATP6. Such mutations attenuate, but cannot abrogate, antimalarial activities of artemisinins. Overall, parasite resistance to artemisinins arises through enhancement of antioxidant defense mechanisms.
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Affiliation(s)
- Richard K Haynes
- Department of Chemistry, Institute of Molecular Technology for Drug Discovery and Synthesis, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, PR China.
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7
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CRISTINO MARIADAGLÓRIAG, DE MENESES CARLACAROLINAF, SOEIRO MALÚCIAMARQUES, FERREIRA JOÃOELIASV, DE FIGUEIREDO ANTONIOFLORÊNCIO, BARBOSA JARDELPINTO, DE ALMEIDA RUTHCO, PINHEIRO JOSÉC, PINHEIRO ANDRÉIADELOURDESR. COMPUTATIONAL MODELING OF ANTIMALARIAL 10-SUBSTITUTED DEOXOARTEMISININS. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2012. [DOI: 10.1142/s0219633612500162] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Nineteen 10-substitued deoxoartemisinin derivatives and artemisinin with activity against D-6 strains of malarial falciparum designated as Sierra Leone are studied. We use molecular electrostatic potential maps in an attempt to identify key structural features of the artemisinins that are necessary for their activities and molecular docking to investigate the interaction with the molecular receptor (heme). Chemometric modeling: Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA), K-Nearest Neighbor (KNN), Soft Independent Modeling of Class Analogy (SIMCA) and Stepwise Discriminant Analysis (SDA) are employed to reduce dimensionality and investigate which subset of descriptors are responsible for the classification between more active (MA) and less active (LA) artemisinins. The PCA, HCA, KNN, SIMCA and SDA studies showed that the descriptors LUMO (Lowest Unoccupied Molecular Orbital) energy, DFeO1 (Distance between the O 1 atom from ligand and iron atom from heme), X1A (Average Connectivity Index Chi-1) and Mor15u (Molecular Representation of Structure Based on Electron Diffraction) code of signal 15, unweighted, are responsible for separating the artemisinins according to their degree of antimalarial activity. The prediction study was done with a new set of eight artemisinins by using the chemometric methods and five of them were predicted as active against D-6 strains of falciparum malaria. In order to verify if the key structural features that are necessary for their antimalarial activities were investigated for the interaction with the heme, we also carried out calculations of the molecular electrostatic potential (MEP) and molecular docking. MEP maps and molecular docking were analyzed for more active compounds of the prediction set.
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Affiliation(s)
- MARIA DA GLÓRIA G. CRISTINO
- Laboratório de Química Teórica e Computacional, Faculdade de Química, Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, Belém, PA, CEP: 66075-110, Brazil
| | - CARLA CAROLINA F. DE MENESES
- Laboratório de Química Teórica e Computacional, Faculdade de Química, Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, Belém, PA, CEP: 66075-110, Brazil
| | - MALÚCIA MARQUES SOEIRO
- Laboratório de Química Teórica e Computacional, Faculdade de Química, Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, Belém, PA, CEP: 66075-110, Brazil
| | - JOÃO ELIAS V. FERREIRA
- Laboratório de Química Teórica e Computacional, Faculdade de Química, Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, Belém, PA, CEP: 66075-110, Brazil
| | - ANTONIO FLORÊNCIO DE FIGUEIREDO
- Laboratório de Química Teórica e Computacional, Faculdade de Química, Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, Belém, PA, CEP: 66075-110, Brazil
| | - JARDEL PINTO BARBOSA
- Laboratório de Química Teórica e Computacional, Faculdade de Química, Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, Belém, PA, CEP: 66075-110, Brazil
| | - RUTH C. O. DE ALMEIDA
- Laboratório de Química Teórica e Computacional, Faculdade de Química, Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, Belém, PA, CEP: 66075-110, Brazil
| | - JOSÉ C. PINHEIRO
- Laboratório de Química Teórica e Computacional, Faculdade de Química, Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, Belém, PA, CEP: 66075-110, Brazil
| | - ANDRÉIA DE LOURDES R. PINHEIRO
- Departamento de Química e Biologia, Centro de Educação, Ciências Exatas e Naturais, Universidade Estadual do Maranhão, Cidade Universitária Paulo VI, Caixa Postal 09, CEP 65055-900 São Luís, MA, Brazil
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8
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Haynes RK, Cheu KW, Li KY, Tang MMK, Wong HN, Chen MJ, Guo ZF, Guo ZH, Coghi P, Monti D. A partial convergence in action of methylene blue and artemisinins: antagonism with chloroquine, a reversal with verapamil, and an insight into the antimalarial activity of chloroquine. ChemMedChem 2011; 6:1603-15. [PMID: 21994127 DOI: 10.1002/cmdc.201100184] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 06/13/2011] [Indexed: 12/19/2022]
Abstract
Artemisinins rapidly oxidize leucomethylene blue (LMB) to methylene blue (MB); they also oxidize dihydroflavins such as the reduced conjugates RFH₂ of riboflavin (RF), and FADH₂ of the cofactor flavin adenine dinucleotide (FAD), to the corresponding flavins. Like the artemisinins, MB oxidizes FADH₂, but unlike artemisinins, it also oxidizes NAD(P)H. Like MB, artemisinins are implicated in the perturbation of redox balance in the malaria parasite by interfering with parasite flavoenzyme disulfide reductases. The oxidation of LMB by artemisinin is inhibited by chloroquine (CQ), an inhibition that is abruptly reversed by verapamil (VP). CQ also inhibits artemisinin-mediated oxidation of RFH₂ generated from N-benzyl-1,4-dihydronicotinamide (BNAH)-RF, or FADH₂ generated from NADPH or NADPH-Fre, an effect that is also modulated by verapamil. The inhibition likely proceeds by the association of LMB or dihydroflavin with CQ, possibly involving donor-acceptor or π complexes that hinder oxidation by artemisinin. VP competitively associates with CQ, liberating LMB or dihydroflavin from their respective CQ complexes. The observations explain the antagonism between CQ-MB and CQ-artemisinins in vitro, and are reconcilable with CQ perturbing intraparasitic redox homeostasis. They further suggest that a VP-CQ complex is a means by which VP reverses CQ resistance, wherein such a complex is not accessible to the putative CQ-resistance transporter (PfCRT).
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Affiliation(s)
- Richard K Haynes
- Department of Chemistry, Institute of Molecular Technology for Drug Discovery and Synthesis, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P.R. China.
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9
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Haynes RK, Cheu KW, Tang MMK, Chen MJ, Guo ZF, Guo ZH, Coghi P, Monti D. Reactions of Antimalarial Peroxides with Each of Leucomethylene Blue and Dihydroflavins: Flavin Reductase and the Cofactor Model Exemplified. ChemMedChem 2010; 6:279-91. [DOI: 10.1002/cmdc.201000508] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Indexed: 11/07/2022]
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10
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Liu Y, Lok CN, Ko BCB, Shum TYT, Wong MK, Che CM. Subcellular localization of a fluorescent artemisinin derivative to endoplasmic reticulum. Org Lett 2010; 12:1420-3. [PMID: 20192248 DOI: 10.1021/ol902890j] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A cytotoxic artemisinin derivative conjugated with a fluorescent dansyl moiety was synthesized and its subcellular localization in Hep3B cells was examined. Comparison of the localization signals of the fluorescent artemisinin derivative with organelle specific dyes revealed that endoplasmic reticulum (ER) is the main site of its accumulation.
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Affiliation(s)
- Yungen Liu
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
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11
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Coghi P, Basilico N, Taramelli D, Chan WC, Haynes R, Monti D. Interaction of Artemisinins with Oxyhemoglobin Hb-FeII, Hb-FeII, CarboxyHb-FeII, Heme-FeII, and Carboxyheme FeII: Significance for Mode of Action and Implications for Therapy of Cerebral Malaria. ChemMedChem 2009; 4:2045-53. [DOI: 10.1002/cmdc.200900342] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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12
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Progress in the development of peroxide-based anti-parasitic agents. Drug Discov Today 2009; 14:793-803. [DOI: 10.1016/j.drudis.2009.05.008] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Revised: 03/05/2009] [Accepted: 05/12/2009] [Indexed: 11/24/2022]
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13
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Araújo NCP, Barton V, Jones M, Stocks PA, Ward SA, Davies J, Bray PG, Shone AE, Cristiano MLS, O'Neill PM. Semi-synthetic and synthetic 1,2,4-trioxaquines and 1,2,4-trioxolaquines: synthesis, preliminary SAR and comparison with acridine endoperoxide conjugates. Bioorg Med Chem Lett 2009; 19:2038-43. [PMID: 19251414 DOI: 10.1016/j.bmcl.2009.02.013] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2008] [Revised: 02/04/2009] [Accepted: 02/04/2009] [Indexed: 11/18/2022]
Abstract
A novel series of semi-synthetic trioxaquines and synthetic trioxolaquines were prepared, in moderate to good yields. Antimalarial activity was evaluated against both the chloroquine-sensitive 3D7 and resistant K1 strain of Plasmodium falciparum and both series of compounds were shown to be active in the low nanomolar range. For comparison the corresponding 9-amino acridine analogues were also prepared and shown to have low nanomolar activity like their quinoline counterparts.
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Affiliation(s)
- Nuna C P Araújo
- Centro de Ciências do Mar and Departamento de Química e Bioquímica, F.C.T, Campus de Gambelas, Universidade do Algarve, 8005-039 Faro, Portugal
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14
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Cardoso FJB, de Figueiredo AF, da Silva Lobato M, de Miranda RM, de Almeida RCO, Pinheiro JC. A study on antimalarial artemisinin derivatives using MEP maps and multivariate QSAR. J Mol Model 2007; 14:39-48. [PMID: 17968600 DOI: 10.1007/s00894-007-0249-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2007] [Accepted: 10/04/2007] [Indexed: 12/26/2022]
Abstract
Artemisinin and some derivatives with activity against D-6 strains of Plasmodium falciparum were studied. Molecular electrostatic potential (MEP) maps were used in an attempt to identify key features of the compounds that are necessary for their activities, and then use those to propose new artemisinin derivatives. The partial least squares (PLS) method was then used to generate a predictive model. The PLS model with three latent variables explaining 88.9% of total variance, with Q((2)) = 0.839 and R(2) = 0.935, was obtained for 15/6 compounds in the training/external validation set. For construction of the model, the most important descriptors were the highest occupied molecular orbital (HOMO) energy, atomic charges on the atoms O1 (Q(1)) and C3 (Q(3)), molecular volume (VOL), and hydrophilic index (HYF). From a set of 20 proposed artemisinin derivatives, one new compound (39) with higher antimalarial activity than the molecules initially studied was predicted. Synthesis of these new derivatives may follow the results of the MEP maps studied and the PLS modeling.
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Affiliation(s)
- Fábio José B Cardoso
- Laboratório de Química Teórica e Computacional, Departamento de Química, Centro de Ciências Exatas e Naturais, Universidade Federal do Pará, CP 101101, 66075-110, Belém, PA, Amazônia, Brazil
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15
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Haynes RK, Chan WC, Lung CM, Uhlemann AC, Eckstein U, Taramelli D, Parapini S, Monti D, Krishna S. The Fe2+-Mediated Decomposition, PfATP6 Binding, and Antimalarial Activities of Artemisone and Other Artemisinins: The Unlikelihood of C-Centered Radicals as Bioactive Intermediates. ChemMedChem 2007; 2:1480-97. [PMID: 17768732 DOI: 10.1002/cmdc.200700108] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The results of Fe(2+)-induced decomposition of the clinically used artemisinins, artemisone, other aminoartemisinins, 10-deoxoartemisinin, and the 4-fluorophenyl derivative have been compared with their antimalarial activities and their ability to inhibit the parasite SERCA PfATP6. The clinical artemisinins and artemisone decompose under aqueous conditions to give mixtures of C radical marker products, carbonyl compounds, and reduction products. The 4-fluorophenyl derivative and aminoartemisinins tend to be inert to aqueous iron(II) sulfate and anhydrous iron(II) acetate. Anhydrous iron(II) bromide enhances formation of the carbonyl compounds and provides a deoxyglycal from DHA and enamines from the aminoartemisinins. Ascorbic acid (AA) accelerates the aqueous Fe(2+)-mediated decompositions, but does not alter product distribution. 4-Oxo-TEMPO intercepts C radicals from a mixture of an antimalaria-active trioxolane, 10-deoxoartemisinin, and anhydrous iron(II) acetate to give trapped products in 73 % yield from the trioxolane, and 3 % from the artemisinin. Artemisone provides a trapped product in 10 % yield. Thus, in line with its structural rigidity, only the trioxolane provides a C radical eminently suited for intermolecular trapping. In contrast, the structural flexibility of the C radicals from the artemisinins allows facile extrusion of Fe(2+) and collapse to benign isomerization products. The propensity towards the formation of radical marker products and intermolecular radical trapping have no relationship with the in vitro antimalarial activities of the artemisinins and trioxolane. Desferrioxamine (DFO) attenuates inhibition of PfATP6 by, and antagonizes antimalarial activity of, the aqueous Fe(2+)-susceptible artemisinins, but has no overt effect on the aqueous Fe(2+)-inert artemisinins. It is concluded that the C radicals cannot be responsible for antimalarial activity and that the Fe(2+)-susceptible artemisinins may be competitively decomposed in aqueous extra- and intracellular compartments by labile Fe(2+), resulting in some attenuation of their antimalarial activities. Interpretations of the roles of DFO and AA in modulating antimalarial activities of the artemisinins, and a comparison with antimalarial properties of simple hydroperoxides and their behavior towards thapsigargin-sensitive SERCA ATPases are presented. The general basis for the exceptional antimalarial activities of artemisinins in relation to the intrinsic activity of the peroxide within the uniquely stressed environment of the malaria parasite is thereby adumbrated.
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Affiliation(s)
- Richard K Haynes
- Department of Chemistry, Open Laboratory of Chemical Biology, Institute of Molecular Technology for Drug Discovery and Synthesis, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, PR China.
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16
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Liu Y, Xiao W, Wong MK, Che CM. Transition-Metal-Catalyzed Group Transfer Reactions for Selective C−H Bond Functionalization of Artemisinin. Org Lett 2007; 9:4107-10. [PMID: 17880226 DOI: 10.1021/ol071269r] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Three types of novel artemisinin derivatives have been synthesized through transition-metal-catalyzed intramolecular carbenoid and nitrenoid C-H bond insertion reactions. With rhodium complexes as catalysts, lactone 11 was synthesized via carbene insertion reaction at the C16 position in 90% yield; oxazolidinone 13 was synthesized via nitrene insertion reaction at the C10 position in 87% yield based on 77% conversion; and sulfamidate 14 was synthesized via nitrene insertion reaction at the C8 position in 87% yield.
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Affiliation(s)
- Yungen Liu
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
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17
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Haynes RK, Fugmann B, Stetter J, Rieckmann K, Heilmann HD, Chan HW, Cheung MK, Lam WL, Wong HN, Croft SL, Vivas L, Rattray L, Stewart L, Peters W, Robinson BL, Edstein MD, Kotecka B, Kyle DE, Beckermann B, Gerisch M, Radtke M, Schmuck G, Steinke W, Wollborn U, Schmeer K, Römer A. Artemisone--a highly active antimalarial drug of the artemisinin class. Angew Chem Int Ed Engl 2007; 45:2082-8. [PMID: 16444785 DOI: 10.1002/anie.200503071] [Citation(s) in RCA: 180] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Richard K Haynes
- Department of Chemistry, Open Laboratory of Chemical Biology, Institute of Molecular Technology for Drug Discovery and Synthesis, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, PR China.
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18
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Ponmee N, Chuchue T, Wilairat P, Yuthavong Y, Kamchonwongpaisan S. Artemisinin effectiveness in erythrocytes is reduced by heme and heme-containing proteins. Biochem Pharmacol 2007; 74:153-60. [PMID: 17498668 PMCID: PMC1949810 DOI: 10.1016/j.bcp.2007.03.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2007] [Revised: 03/11/2007] [Accepted: 03/12/2007] [Indexed: 11/25/2022]
Abstract
Artemisinin loses its antimalarial activity on prolonged exposure to erythrocytes, especially alpha-thalassemic erythrocytes. In this report, we show that the major artemisinin-inactivating factor in cytosol of normal erythrocytes was heat-labile but a heat-stable factor from alpha-thalassemic cells also played a significant role in reducing artemisinin effectiveness, which was shown to be heme released from hemoglobin (Hb). Studies of fractionated lysate from genetically normal erythrocytes revealed that the protein fraction with molecular weight greater than 100 kDa was capable of reducing artemisinin effectiveness more readily than lower molecular weight fraction. Catalase and Hb A, but not selenoprotein glutathione peroxidase, were capable of reducing artemisinin effectiveness. Hemin (ferriprotoporphyrin IX) also reduced artemisinin effectiveness in a concentration- and time-dependent manner. It is concluded that heme and heme-containing proteins in erythrocyte are largely responsible for reducing artemisinin effectiveness and may contribute to resistance of Plasmodium falciparum infecting alpha-thalassemic erythrocytes observed in vitro.
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Affiliation(s)
- Napawan Ponmee
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathumthani 12120
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Tatsanee Chuchue
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Prapon Wilairat
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Yongyuth Yuthavong
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathumthani 12120
| | - Sumalee Kamchonwongpaisan
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathumthani 12120
- *Corresponding author: Sumalee Kamchonwongpaisan, Ph.D., National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 113 Thailand Science Park, Klong Luang, Pathumthani 12120, Thailand. Tel.: +662 564 6700 ext 3484; FAX: +662 564 6707; E-mail address:
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19
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Zmitek K, Stavber S, Zupan M, Bonnet-Delpon D, Charneau S, Grellier P, Iskra J. Synthesis and antimalarial activities of novel 3,3,6,6-tetraalkyl-1,2,4,5-tetraoxanes. Bioorg Med Chem 2006; 14:7790-5. [PMID: 16919459 DOI: 10.1016/j.bmc.2006.07.069] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2006] [Revised: 07/27/2006] [Accepted: 07/31/2006] [Indexed: 11/18/2022]
Abstract
The oxidative system H2O2/fluorinated alcohol (TFE, HFIP) was used for direct acid- and MeReO3-catalyzed synthesis of 1,2,4,5-tetraoxanes from cyclic (C6, C7, and C12) and acyclic ketones. The influence of ring size and alkyl chain length were studied and antimalarial activities of synthetic 3,3,6,6-tetraalkyl-1,2,4,5-tetraoxanes were determined. Variations in their antimalarial activities were significant, although they share similar electrochemical properties of the peroxide bond.
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Affiliation(s)
- Katja Zmitek
- Laboratory of Organic and Bioorganic Chemistry, Jozef Stefan Institute and Faculty of Chemistry and Chemical Technology of University of Ljubljana, Jamova 39, 1000 Ljubljana, Slovenia
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20
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Krishna S, Woodrow CJ, Staines HM, Haynes RK, Mercereau-Puijalon O. Re-evaluation of how artemisinins work in light of emerging evidence of in vitro resistance. Trends Mol Med 2006; 12:200-5. [PMID: 16616639 PMCID: PMC2682190 DOI: 10.1016/j.molmed.2006.03.005] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2006] [Revised: 03/02/2006] [Accepted: 03/27/2006] [Indexed: 11/18/2022]
Abstract
There are more than half a billion cases of malaria every year. Combinations of an artemisinin with other antimalarial drugs are now recommended treatments for Plasmodium falciparum malaria in most endemic areas. These treatment regimens act rapidly to relieve symptoms and effect cure. There is considerable controversy on how artemisinins work and over emerging indications of resistance to this class of antimalarial drugs. Several individual molecules have been proposed as targets for artemisinins, in addition to the idea that artemisinins might have many targets at the same time. Our suggestion that artemisinins inhibit the parasite-encoded sarco–endoplasmic reticulum Ca2+-ATPase (SERCA) PfATP6 has gained support from recent observations that a polymorphism in the gene encoding PfATP6 is associated with in vitro resistance to artemether in field isolates of P. falciparum.
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Affiliation(s)
- Sanjeev Krishna
- Centre for Infection, Division of Cellular and Molecular Medicine, St. George's, University of London SW17 0RE, UK.
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21
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Haynes RK, Fugmann B, Stetter J, Rieckmann K, Heilmann HD, Chan HW, Cheung MK, Lam WL, Wong HN, Croft SL, Vivas L, Rattray L, Stewart L, Peters W, Robinson BL, Edstein MD, Kotecka B, Kyle DE, Beckermann B, Gerisch M, Radtke M, Schmuck G, Steinke W, Wollborn U, Schmeer K, Römer A. Artemisone—A Highly Active Antimalarial Drug of the Artemisinin Class. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200503071] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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