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Redway A, Spry C, Brown A, Wiedemann U, Fathoni I, Garnie LF, Qiu D, Egan TJ, Lehane AM, Jackson Y, Saliba KJ, Downer-Riley N. Discovery of antiplasmodial pyridine carboxamides and thiocarboxamides. Int J Parasitol Drugs Drug Resist 2024; 25:100536. [PMID: 38663046 PMCID: PMC11068522 DOI: 10.1016/j.ijpddr.2024.100536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 03/30/2024] [Accepted: 04/01/2024] [Indexed: 05/07/2024]
Abstract
Malaria continues to be a significant burden, particularly in Africa, which accounts for 95% of malaria deaths worldwide. Despite advances in malaria treatments, malaria eradication is hampered by insecticide and antimalarial drug resistance. Consequently, the need to discover new antimalarial lead compounds remains urgent. To help address this need, we evaluated the antiplasmodial activity of twenty-two amides and thioamides with pyridine cores and their non-pyridine analogues. Twelve of these compounds showed in vitro anti-proliferative activity against the intraerythrocytic stage of Plasmodium falciparum, the most virulent species of Plasmodium infecting humans. Thiopicolinamide 13i was found to possess submicromolar activity (IC50 = 142 nM) and was >88-fold less active against a human cell line. The compound was equally effective against chloroquine-sensitive and -resistant parasites and did not inhibit β-hematin formation, pH regulation or PfATP4. Compound 13i may therefore possess a novel mechanism of action.
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Affiliation(s)
- Alexa Redway
- Department of Chemistry, The University of the West Indies, Mona, Kingston 7, Jamaica; Chemistry Divison, University of Technology, 237 Old Hope Road, Kingston 6, Jamaica
| | - Christina Spry
- Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Ainka Brown
- Department of Chemistry, The University of the West Indies, Mona, Kingston 7, Jamaica
| | - Ursula Wiedemann
- Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Imam Fathoni
- Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Larnelle F Garnie
- Department of Chemistry, University of Cape Town, Rondebosch, 7701, South Africa
| | - Deyun Qiu
- Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Timothy J Egan
- Department of Chemistry, University of Cape Town, Rondebosch, 7701, South Africa; Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Observatory, 7925, South Africa
| | - Adele M Lehane
- Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Yvette Jackson
- Department of Chemistry, The University of the West Indies, Mona, Kingston 7, Jamaica
| | - Kevin J Saliba
- Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Nadale Downer-Riley
- Department of Chemistry, The University of the West Indies, Mona, Kingston 7, Jamaica.
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2
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Identifying inhibitors of β-haematin formation with activity against chloroquine-resistant Plasmodium falciparum malaria parasites via virtual screening approaches. Sci Rep 2023; 13:2648. [PMID: 36788274 PMCID: PMC9929333 DOI: 10.1038/s41598-023-29273-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 02/01/2023] [Indexed: 02/16/2023] Open
Abstract
The biomineral haemozoin, or its synthetic analogue β-haematin (βH), has been the focus of several target-based screens for activity against Plasmodium falciparum parasites. Together with the known βH crystal structure, the availability of this screening data makes the target amenable to both structure-based and ligand-based virtual screening. In this study, molecular docking and machine learning techniques, including Bayesian and support vector machine classifiers, were used in sequence to screen the in silico ChemDiv 300k Representative Compounds library for inhibitors of βH with retained activity against P. falciparum. We commercially obtained and tested a prioritised set of inhibitors and identified the coumarin and iminodipyridinopyrimidine chemotypes as potent in vitro inhibitors of βH and whole cell parasite growth.
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Kuaprasert B, Chitnumsub P, Leartsakulpanich U, Suginta W, Leelayoova S, Mungthin M, Sitthichot N, Rattanabunyong S, Kiriwan D, Choowongkomon K. Dual role of azo compounds in inhibiting Plasmodium falciparum adenosine deaminase and hemozoin biocrystallization. Exp Parasitol 2022; 243:108384. [PMID: 36154837 DOI: 10.1016/j.exppara.2022.108384] [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: 10/07/2021] [Revised: 08/09/2022] [Accepted: 09/17/2022] [Indexed: 11/28/2022]
Abstract
Protein-ligand (GOLD) docking of the NCI compounds into the ligand-binding site of Plasmodium falciparum adenosine deaminase (PfADA) identified three most active azo compounds containing 4-[(4-hydroxy-2-oxo-1H-quinolin-3-yl) moiety. These compounds showed IC50 of 3.7-15.4 μM against PfADA, as well as inhibited the growth of P. falciparum strains 3D7 (chloroquine (CQ)-sensitive) and K1 (CQ-resistant) with IC50 of 1.8-3.1 and 1.7-3.6 μM, respectively. The identified compounds have structures similar to the backbone structure (4-N-(7-chloroquinolin-4-yl)) in CQ, and NSC45545 could mimic CQ by inhibiting the bioformation of hemozoin in parasitic food vacuole. The amount of in situ hemozoin in the ring-stage parasite was determined using a combination of synchrotron transmission Fourier transform infrared microspectroscopy and Principal Component Analysis. Stretching of the C-O bond of hemozoin propionate group measured at 1220-1210 cm-1 in untreated intraerythrocytic P. falciparum strains 3D7 and K1 was disappeared following treatment with 1.85 and 1.74 μM NSC45545, similar to those treated with 0.02 and 0.13 μM CQ, respectively. These findings indicate a novel dual function of 4-[(4-hydroxy-2-oxo-1H-quinolin-3-yl) azo compounds in inhibiting both PfADA and in situ hemozoin biocrystallization. These lead compounds hold promise for further development of new antimalarial therapeutics that could delay the onset of parasitic drug resistance.
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Affiliation(s)
- Buabarn Kuaprasert
- Research and Facility Department, Synchrotron Light Research Institute (Public Organization), 111 University Avenue, Muang District, Nakhon Ratchasima, 30000, Thailand.
| | - Penchit Chitnumsub
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 113 Phahon Yothin Road, Klong Luang, Pathumthani, 12120, Thailand
| | - Ubolsree Leartsakulpanich
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 113 Phahon Yothin Road, Klong Luang, Pathumthani, 12120, Thailand
| | - Wipa Suginta
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), 555 Payupnai, Wangchan, Rayong, 21210, Thailand
| | - Saovanee Leelayoova
- Department of Parasitology, Phramongkutklao College of Medicine, 317 Ratchawithi Road, Ratchathewi, Bangkok, 10400, Thailand
| | - Mathirut Mungthin
- Department of Parasitology, Phramongkutklao College of Medicine, 317 Ratchawithi Road, Ratchathewi, Bangkok, 10400, Thailand
| | - Naruemon Sitthichot
- Department of Parasitology, Phramongkutklao College of Medicine, 317 Ratchawithi Road, Ratchathewi, Bangkok, 10400, Thailand
| | - Siriluk Rattanabunyong
- Department of Biochemistry, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Ladyaow, Chatuchak, Bangkok, 10900, Thailand
| | - Duangnapa Kiriwan
- Department of Biochemistry, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Ladyaow, Chatuchak, Bangkok, 10900, Thailand
| | - Kiattawee Choowongkomon
- Department of Biochemistry, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan Road, Ladyaow, Chatuchak, Bangkok, 10900, Thailand; Center for Advanced Studies in Nanotechnology for Chemical, Food and Agricultural Industries, KU Institute for Advanced Studies, 50 Ngam Wong Wan Road, Ladyaow, Chatuchak, Kasetsart University, Bangkok, 10700, Thailand
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4
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Olivier T, Loots L, Kok M, de Villiers M, Reader J, Birkholtz LM, Arnott GE, de Villiers KA. Adsorption to the surface of hemozoin crystals: Structure-based design and synthesis of new amino-phenoxazine β-hematin inhibitors. ChemMedChem 2022; 17:e202200139. [PMID: 35385211 DOI: 10.1002/cmdc.202200139] [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: 03/16/2022] [Revised: 04/05/2022] [Indexed: 11/07/2022]
Abstract
In silico adsorption of eight antimalarials that inhibit β-hematin (synthetic hemozoin) formation identified a primary binding site on the (001) face, which accommodates inhibitors via formation of predominantly π-π interactions. A good correlation (r2 = 0.64, P = 0.017) between adsorption energies and the logarithm of β-hematin inhibitory activity was found for this face. Of 53 monocyclic, bicyclic and tricyclic scaffolds, the latter yielded the most favorable adsorption energies. Five new amino-phenoxazine compounds were pursued as β-hematin inhibitors based on adsorption behaviour. The 2-substituted phenoxazines show good to moderate β-hematin inhibitory activity (< 100 μM) and Plasmodium falciparum blood stage activity against the 3D7 strain. N1,N1-diethyl-N4-(10H-phenoxazin-2-yl)pentane-1,4-diamine (P2a) is the most promising hit with IC50 values of 4.7 ± 0.6 and 0.64 ± 0.05 μM, respectively. Adsorption energies are predictive of β-hematin inhibitory activity, and thus the in silico approach is a beneficial tool for structure-based development of new non-quinoline inhibitors.
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Affiliation(s)
- Tania Olivier
- Stellenbosch University Faculty of Science, Chemistry and Polymer Science, SOUTH AFRICA
| | - Leigh Loots
- Stellenbosch University Faculty of Science, Chemistry and Polymer Science, SOUTH AFRICA
| | - Michélle Kok
- Stellenbosch University Faculty of Science, Biochemistry, SOUTH AFRICA
| | | | - Janette Reader
- University of Pretoria, Biochemistry, Genetics and Microbiology, SOUTH AFRICA
| | - Lyn-Marié Birkholtz
- University of Pretoria, Biochemistry, Genetics and Microbiology, SOUTH AFRICA
| | - Gareth E Arnott
- Stellenbosch University Faculty of Science, Chemistry and Polymer Science, 49 Almond Drive, Helderberg Estate, 7130, Somerset West, SOUTH AFRICA
| | - Katherine A de Villiers
- Stellenbosch University Faculty of Science, Chemistry and Polymer Science, Merriman Avenue, 7600, Stellenbosch, SOUTH AFRICA
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Synthesis and Structural Characterization of Pyridine-2,6-dicarboxamide and Furan-2,5-dicarboxamide Derivatives. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27061819. [PMID: 35335183 PMCID: PMC8948770 DOI: 10.3390/molecules27061819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 02/22/2022] [Accepted: 03/08/2022] [Indexed: 11/17/2022]
Abstract
Derivatives based on pyridine-2-6- and furan-2,5-dicarboxamide scaffolds reveal numerous chemical properties and biological activities. This fact makes them an exciting research topic in supramolecular and coordination chemistry and in discovering new pharmacologically-active compounds. This work aimed to obtain a series of symmetrical pyridine-2-6- and furan-2,5-dicarboxamides through a condensation reaction of the appropriate acyl chlorides and aromatic amides. Successful syntheses were confirmed with NMR spectroscopy. We solved their crystal structures for seven compounds; two pyridine and five furan derivatives. Based on our crystallographic studies, we were able to indicate supramolecular features of the crystals under investigation. Additionally, Hirshfeld surface analysis allowed us to calculate a distribution of intermolecular contacts in the dicarboxamide crystals.
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6
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Thissera B, Hallyburton I, Ngwa CJ, Cherif-Silini H, Hassane ASI, Anderson M, Campbell LA, Mutter N, Eshelli M, Abdelmohsen UR, Yaseen M, Pradel G, Belbahri L, Elgendy B, Hegazy L, Rateb ME. Potent antiplasmodial alkaloids from the rhizobacterium Pantoea agglomerans as hemozoin modulators. Bioorg Chem 2021; 115:105215. [PMID: 34358799 DOI: 10.1016/j.bioorg.2021.105215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 07/16/2021] [Accepted: 07/24/2021] [Indexed: 12/22/2022]
Abstract
Global health concern regarding malaria has increased since the first report of artemisinin-resistant Plasmodium falciparum (Pf) two decades ago. The current therapies suffer various drawbacks such as low efficacy and significant side effects, alarming for an urgent need of more effective and less toxic drugs with higher patient compliance. Chemical entities with natural origins become progressively attractive as new drug leads due to their structural diversity and bio-compatibility. This study initially aimed at the targeted isolation of hydroxyquinoline derivatives following our published genomics and metabolomics study of Pantoea agglomerans (Pa). Fermentation of Pa on a pre-selected medium followed by chromatographic isolation, NMR and HRMS analyses led to the characterisation of one new hydroxyquinoline alkaloid together with another six known congeners and two known hydroxyquinolone derivatives. When screened for their antimalarial activity by high throughput screening against asexual blood-stage parasites, almost all compounds showed potent and selective sub-micromolar activities. Computational investigation was performed to identify the antiplasmodial potential targets. Ligand-based similarity search predicted the tested compounds to act as hemozoin inhibitors. Computational target identification results were further validated by competitive hemozoin inhibitory properties of hydroxyquinoline and hydroxyquinolone derivatives in vitro. The overall results suggest this natural scaffold is of potential to be developed as antimalarial drug lead.
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Affiliation(s)
- Bathini Thissera
- School of Computing, Engineering and Physical Sciences, University of the West of Scotland, PA12BE Paisley, UK
| | - Irene Hallyburton
- Drug Discovery Unit, Wellcome Centre for Anti-infective Research, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Che Julius Ngwa
- Division of Cellular and Applied Infection Biology, Institute of Zoology, RWTH Aachen University, 52074 Aachen, Germany
| | - Hafsa Cherif-Silini
- Laboratory of Applied Microbiology, Department of Microbiology, Faculty of Natural and Life Sciences, Ferhat Abbas University, Setif 19000, Algeria
| | - Ahmed S I Hassane
- Aberdeen Royal Infirmary, Foresterhill Health Campus, Foresterhill Road, Aberdeen AB25 2ZN, Scotland, UK
| | - Mark Anderson
- Drug Discovery Unit, Wellcome Centre for Anti-infective Research, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Lorna A Campbell
- Drug Discovery Unit, Wellcome Centre for Anti-infective Research, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Nicole Mutter
- Drug Discovery Unit, Wellcome Centre for Anti-infective Research, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Manal Eshelli
- School of Computing, Engineering and Physical Sciences, University of the West of Scotland, PA12BE Paisley, UK; Food Science and Technology Department, Faculty of Agriculture, University of Tripoli, Tripoli 13275, Libya
| | - Usama R Abdelmohsen
- Department of Pharmacognosy, Faculty of Pharmacy, Minia University, Minia 61519, Egypt; Department of Pharmacognosy, Faculty of Pharmacy, Deraya University, Minia 61519, Egypt
| | - Mohammed Yaseen
- School of Computing, Engineering and Physical Sciences, University of the West of Scotland, PA12BE Paisley, UK
| | - Gabriele Pradel
- Division of Cellular and Applied Infection Biology, Institute of Zoology, RWTH Aachen University, 52074 Aachen, Germany
| | - Lassaad Belbahri
- Laboratory of Soil Biology, University of Neuchatel, 2000 Neuchatel, Switzerland
| | - Bahaa Elgendy
- Center for Clinical Pharmacology, Washington University School of Medicine and University of Health Sciences and Pharmacy, St. Louis, MO 63110, USA; Chemistry Department, Faculty of Science, Benha University, Benha 13518, Egypt
| | - Lamees Hegazy
- Center for Clinical Pharmacology, Washington University School of Medicine and University of Health Sciences and Pharmacy, St. Louis, MO 63110, USA.
| | - Mostafa E Rateb
- School of Computing, Engineering and Physical Sciences, University of the West of Scotland, PA12BE Paisley, UK.
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7
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de Villiers KA, Egan TJ. Heme Detoxification in the Malaria Parasite: A Target for Antimalarial Drug Development. Acc Chem Res 2021; 54:2649-2659. [PMID: 33982570 DOI: 10.1021/acs.accounts.1c00154] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Over the last century, malaria deaths have decreased by more than 85%. Nonetheless, there were 405 000 deaths in 2018, mostly resulting from Plasmodium falciparum infection. In the 21st century, much of the advance has arisen from the deployment of insecticide-treated bed nets and artemisinin combination therapy. However, over the past few decades parasites with a delayed artemisinin clearance phenotype have appeared in Southeast Asia, threatening further gains. The effort to find new drugs is thus urgent. A prominent process in blood stage malaria parasites, which we contend remains a viable drug target, is hemozoin formation. This crystalline material consisting of heme can be readily seen when parasites are viewed microscopically. The process of its formation in the parasite, however, is still not fully understood.In early work, we recognized hemozoin formation as a biomineralization process. We have subsequently investigated the kinetics of synthetic hemozoin (β-hematin) crystallization catalyzed at lipid-aqueous interfaces under biomimetic conditions. This led us to the use of neutral detergent-based high-throughput screening (HTS) for inhibitors of β-hematin formation. A good hit rate against malaria parasites was obtained. Simultaneously, we developed a pyridine-based assay which proved successful in measuring the concentrations of hematin not converted to β-hematin.The pyridine assay was adapted to determine the effects of chloroquine and other clinical antimalarials on hemozoin formation in the cell. This permitted the determination of the dose-dependent amounts of exchangeable heme and hemozoin in P. falciparum for the first time. These studies have shown that hemozoin inhibitors cause a dose-dependent increase in exchangeable heme, correlated with decreased parasite survival. Electron spectroscopic imaging (ESI) showed a relocation of heme iron into the parasite cytoplasm, while electron microscopy provided evidence of the disruption of hemozoin crystals. This cellular assay was subsequently extended to top-ranked hits from a wide range of scaffolds found by HTS. Intriguingly, the amounts of exchangeable heme at the parasite growth IC50 values of these scaffolds showed substantial variation. The amount of exchangeable heme was found to be correlated with the amount of inhibitor accumulated in the parasitized red blood cell. This suggests that heme-inhibitor complexes, rather than free heme, lead to parasite death. This was supported by ESI using a Br-containing compound which showed the colocalization of Fe and Br as well as by confocal Raman microscopy which confirmed the presence of a complex in the parasite. Current evidence indicates that inhibitors block hemozoin formation by surface adsorption. Indeed, we have successfully introduced molecular docking with hemozoin to find new inhibitors. It follows that the resulting increase in free heme leads to the formation of the parasiticidal heme-inhibitor complex. We have reported crystal structures of heme-drug complexes for several aryl methanol antimalarials in nonaqueous media. These form coordination complexes but most other inhibitors interact noncovalently, and the determination of their structures remains a major challenge.It is our view that key future developments will include improved assays to measure cellular heme levels, better in silico approaches for predicting β-hematin inhibition, and a concerted effort to determine the structure and properties of heme-inhibitor complexes.
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Affiliation(s)
- Katherine A. de Villiers
- Department of Chemistry and Polymer Science, Stellenbosch University, Private Bag, Matieland 7600, South Africa
| | - Timothy J. Egan
- Department of Chemistry, University of Cape Town, Private Bag, Rondebosch 7701, South Africa
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, Cape Town 7945, South Africa
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8
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Openshaw R, Maepa K, Benjamin SJ, Wainwright L, Combrinck JM, Hunter R, Egan TJ. A Diverse Range of Hemozoin Inhibiting Scaffolds Act on Plasmodium falciparum as Heme Complexes. ACS Infect Dis 2021; 7:362-376. [PMID: 33430579 DOI: 10.1021/acsinfecdis.0c00680] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A diverse series of hemozoin-inhibiting quinolines, benzamides, triarylimidazoles, quinazolines, benzimidazoles, benzoxazoles, and benzothiazoles have been found to lead to exchangeable heme levels in cultured Plasmodium falciparum (NF54) that ranged over an order of magnitude at the IC50. Surprisingly, less active compounds often exhibited higher levels of exchangeable heme than more active ones. Quantities of intracellular inhibitor measured using the inoculum effect exhibited a linear correlation with exchangeable heme, suggesting formation of heme-inhibitor complexes in the parasite. In an effort to confirm this, the presence of a Br atom in one of the benzimidazole derivatives was exploited to image its distribution in the parasite using electron spectroscopic imaging of Br, an element not naturally abundant in cells. This showed that the compound colocalized with iron, consistent with its presence as a heme complex. Direct evidence for this complex was then obtained using confocal Raman microscopy. Exchangeable heme and inhibitor were found to increase with decreased rate of killing, suggesting that slow-acting compounds have more time to build up exchangeable heme complexes. Lastly, some but not all compounds evidently cause pro-oxidant effects because their activity could be attenuated with N-acetylcysteine and potentiated with t-butyl hydroperoxide. Collectively, these findings suggest that hemozoin inhibitors act as complexes with free heme, each with its own unique activity.
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Affiliation(s)
- Roxanne Openshaw
- Department of Chemistry, University of Cape Town, Private Bag Rondebosch, Cape Town 7701, South Africa
| | | | - Stefan J. Benjamin
- Department of Chemistry, University of Cape Town, Private Bag Rondebosch, Cape Town 7701, South Africa
| | - Lauren Wainwright
- Department of Chemistry, University of Cape Town, Private Bag Rondebosch, Cape Town 7701, South Africa
| | | | - Roger Hunter
- Department of Chemistry, University of Cape Town, Private Bag Rondebosch, Cape Town 7701, South Africa
| | - Timothy J. Egan
- Department of Chemistry, University of Cape Town, Private Bag Rondebosch, Cape Town 7701, South Africa
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9
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Veale CGL, Müller R. Recent Highlights in Anti-infective Medicinal Chemistry from South Africa. ChemMedChem 2020; 15:809-826. [PMID: 32149446 DOI: 10.1002/cmdc.202000086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Indexed: 12/17/2022]
Abstract
Global advancements in biological technologies have vastly increased the variety of and accessibility to bioassay platforms, while simultaneously improving our understanding of druggable chemical space. In the South African context, this has resulted in a rapid expansion in the number of medicinal chemistry programmes currently operating, particularly on university campuses. Furthermore, the modern medicinal chemist has the advantage of being able to incorporate data from numerous related disciplines into the medicinal chemistry process, allowing for informed molecular design to play a far greater role than previously possible. Accordingly, this review focusses on recent highlights in drug-discovery programmes, in which South African medicinal chemistry groups have played a substantive role in the design and optimisation of biologically active compounds which contribute to the search for promising agents for infectious disease.
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Affiliation(s)
- Clinton G L Veale
- School of Chemistry and Physics, Pietermaritzburg Campus, University of KwaZulu-Natal, Private Bag X01, Scottsville, 3209, South Africa
| | - Ronel Müller
- School of Chemistry and Physics, Pietermaritzburg Campus, University of KwaZulu-Natal, Private Bag X01, Scottsville, 3209, South Africa
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Kouznetsov VV, Vargas Méndez LY, Puerto Galvis CE, Ortiz Villamizar MC. The direct C–H alkenylation of quinoline N-oxides as a suitable strategy for the synthesis of promising antiparasitic drugs. NEW J CHEM 2020. [DOI: 10.1039/c9nj05054j] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This review highlights the direct C–H alkenylation of quinoline N-oxides covering the metal-free and transition-metal catalysed protocols, and the regioselectivity during the synthesis of antiparasitic drugs based on quinoline scaffold.
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Affiliation(s)
- Vladimir V. Kouznetsov
- Laboratorio de Química Orgánica y Biomolecular
- CMN
- Universidad Industrial de Santander
- Parque Tecnológico Guatiguará
- Piedecuesta 681011
| | - Leonor Y. Vargas Méndez
- Laboratorio de Química Orgánica y Biomolecular
- CMN
- Universidad Industrial de Santander
- Parque Tecnológico Guatiguará
- Piedecuesta 681011
| | - Carlos E. Puerto Galvis
- Laboratorio de Química Orgánica y Biomolecular
- CMN
- Universidad Industrial de Santander
- Parque Tecnológico Guatiguará
- Piedecuesta 681011
| | - Marlyn C. Ortiz Villamizar
- Laboratorio de Química Orgánica y Biomolecular
- CMN
- Universidad Industrial de Santander
- Parque Tecnológico Guatiguará
- Piedecuesta 681011
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11
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Veale CGL, Jayram J, Naidoo S, Laming D, Swart T, Olivier T, Akerman MP, de Villiers KA, Hoppe HC, Jeena V. Insights into structural and physicochemical properties required for β-hematin inhibition of privileged triarylimidazoles. RSC Med Chem 2019; 11:85-91. [PMID: 33479606 DOI: 10.1039/c9md00468h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 10/22/2019] [Indexed: 11/21/2022] Open
Abstract
In this study, we investigated a series of triarylimidazoles, in an effort to elucidate critical SAR information pertaining to their anti-plasmodial and β-hematin inhibitory activity. Our results showed that in addition to the positional effects of ring substitution, subtle changes to lipophilicity and imidazole ionisability were important factors in SAR interpretation. Finally, in silico adsorption analysis indicated that these compounds exert their effect by inhibiting β-hematin crystal growth at the fast growing 001 face.
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Affiliation(s)
- Clinton G L Veale
- School of Chemistry and Physics , Pietermaritzburg Campus , University of KwaZulu-Natal , Private Bag X01 , Scottsville , 3209 , South Africa
| | - Janeeka Jayram
- School of Chemistry and Physics , Pietermaritzburg Campus , University of KwaZulu-Natal , Private Bag X01 , Scottsville , 3209 , South Africa
| | - Shivani Naidoo
- School of Chemistry and Physics , Pietermaritzburg Campus , University of KwaZulu-Natal , Private Bag X01 , Scottsville , 3209 , South Africa
| | - Dustin Laming
- Department of Biochemistry and Microbiology , Rhodes University , Grahamstown , 6140 , South Africa
| | - Tarryn Swart
- Department of Biochemistry and Microbiology , Rhodes University , Grahamstown , 6140 , South Africa
| | - Tania Olivier
- Department of Chemistry and Polymer Science , Stellenbosch University , Private Bag X1 , Matieland , 7602 , South Africa . ;
| | - Matthew P Akerman
- School of Chemistry and Physics , Pietermaritzburg Campus , University of KwaZulu-Natal , Private Bag X01 , Scottsville , 3209 , South Africa
| | - Katherine A de Villiers
- Department of Chemistry and Polymer Science , Stellenbosch University , Private Bag X1 , Matieland , 7602 , South Africa . ;
| | - Heinrich C Hoppe
- Department of Biochemistry and Microbiology , Rhodes University , Grahamstown , 6140 , South Africa
| | - Vineet Jeena
- School of Chemistry and Physics , Pietermaritzburg Campus , University of KwaZulu-Natal , Private Bag X01 , Scottsville , 3209 , South Africa
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12
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Xiang P, Xiao CJ, Xu W, Shan H, Qiu L, Li Y, Dong X, Jiang B. New abietane diterpenoid glucosides from underground parts of Isodon taliensis. JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH 2019; 21:1177-1183. [PMID: 30415590 DOI: 10.1080/10286020.2018.1518321] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 08/28/2018] [Accepted: 08/29/2018] [Indexed: 06/09/2023]
Abstract
Two new abietane diterpenoid glucosides, talienosides A and B (1 and 2), along with four known compounds (3 - 6), were isolated from the ethyl acetate soluble portion of 70% acetone extract of the underground parts of Isodon taliensis. Their structures were elucidated based on the analyses of extensive spectroscopic data and physicochemical properties. The two new compounds were tested for their bioactivities against malaria and diabetes by β-hematin formation inhibition and α-glycosidase inhibition experiments, respectively. However, only 2 showed weak β-hematin formation inhibitory activity. [Formula: see text].
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Affiliation(s)
- Pan Xiang
- College of Pharmacy and Chemistry, Dali University, Dali 671003, China
| | - Chao-Jiang Xiao
- College of Pharmacy and Chemistry, Dali University, Dali 671003, China
- Institute of Materia Medica, Dali University, Dali 671000, China
| | - Wei Xu
- College of Pharmacy and Chemistry, Dali University, Dali 671003, China
| | - Hua Shan
- College of Pharmacy and Chemistry, Dali University, Dali 671003, China
| | - Lin Qiu
- College of Pharmacy and Chemistry, Dali University, Dali 671003, China
| | - Yang Li
- College of Pharmacy and Chemistry, Dali University, Dali 671003, China
| | - Xiang Dong
- College of Pharmacy and Chemistry, Dali University, Dali 671003, China
- Institute of Materia Medica, Dali University, Dali 671000, China
| | - Bei Jiang
- College of Pharmacy and Chemistry, Dali University, Dali 671003, China
- Institute of Materia Medica, Dali University, Dali 671000, China
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13
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Ni S, Li B, Xu Y, Mao F, Li X, Lan L, Zhu J, Li J. Targeting virulence factors as an antimicrobial approach: Pigment inhibitors. Med Res Rev 2019; 40:293-338. [PMID: 31267561 DOI: 10.1002/med.21621] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 05/30/2019] [Accepted: 06/13/2019] [Indexed: 12/19/2022]
Abstract
The fascinating and dangerous colored pathogens contain unique chemically pigmented molecules, which give varied and efficient assistance as virulence factors to the crucial reproduction and growth of microbes. Therefore, multiple novel strategies and inhibitors have been developed in recent years that target virulence factor pigments. However, despite the importance and significance of this topic, it has not yet been comprehensively reviewed. Moreover, research groups around the world have made successful progress against antibacterial infections by targeting pigment production, including our serial works on the discovery of CrtN inhibitors against staphyloxanthin production in Staphylococcus aureus. On the basis of the previous achievements and recent progress of our group in this field, this article will be the first comprehensive review of pigment inhibitors against colored pathogens, especially S. aureus infections, and this article includes design strategies, representative case studies, advantages, limitations, and perspectives to guide future research.
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Affiliation(s)
- Shuaishuai Ni
- Cancer Institute, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Baoli Li
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Yixiang Xu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Fei Mao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Xiaokang Li
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Lefu Lan
- State Key Laboratory of Drug Research, Shanghai Institute of Material Medical, Chinese Academy of Sciences, Shanghai, China
| | - Jin Zhu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Jian Li
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China.,Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai, China
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14
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Xu W, Xiao CJ, Sun JZ, Zhang PP, Wang JW, Dong X, Jiang B. A New Totarane Diterpenoid from the Rhizomes of Isodon lophanthoides. Chem Nat Compd 2019. [DOI: 10.1007/s10600-019-02778-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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15
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Kuter D, Suárez L, Dodd EL, Noll BC, Stephens PW, Bohle DS. Hydrating the Bispropionate Notch in Malaria Pigment: A New Structural Motif in the Iron(III)(deuteroporphyrin) Dimer. Chemistry 2019; 25:4373-4378. [PMID: 30499153 DOI: 10.1002/chem.201805116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Indexed: 11/11/2022]
Abstract
Treating deuterohemin, chloro(deuteroporphyrinato)iron(III), with a non-coordinating base in DMSO/methanol allows for the isolation of [(deuteroporphyrinato)iron(III)]2 , deuterohematin anhydride (DHA), an analogue of malaria pigment, the natural product of heme detoxification by malaria. The structure of DHA obtained from this solvent system has been solved by X-ray powder diffraction analysis and displays many similarities, yet important structural differences, to malaria pigment. Most notably, a water molecule of solvation occupies a notch created by the propionate side chains and stabilizes a markedly bent propionate ligand coordinated with a long Fe-O bond, and a carboxylate cluster associated with water molecules is generated. Together, these features account for its increased solubility and more open structure, with an increased porphyrin-porphyrin separation. The IR spectroscopic signature associated with this structure also accounts for the strong IR band at 1587 cm-1 seen for many amorphous preparations of synthetic malaria pigment, and it is proposed that stabilizing these structures may be a new objective for antimalarial drugs. The important role of the vinyl substituents in this biochemistry is further demonstrated by the structure of deuterohemin obtained by single-crystal X-ray diffraction analysis.
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Affiliation(s)
- David Kuter
- Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal, H3A 0B8, Canada.,Department of Chemistry and Polymer Science, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch, 7602, South Africa
| | - Liliana Suárez
- Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal, H3A 0B8, Canada
| | - Erin L Dodd
- Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal, H3A 0B8, Canada
| | - Bruce C Noll
- Bruker-AXS, 5465 E Cheryl Pkwy, Fitchburg, WI, 53711, USA
| | - Peter W Stephens
- Department of Physics and Astronomy, State University of New York, Stony Brook, Stony Brook, New York, 11794-3800, USA
| | - D Scott Bohle
- Department of Chemistry, McGill University, 801 Sherbrooke St. W., Montreal, H3A 0B8, Canada
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16
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Veale CGL. Unpacking the Pathogen Box-An Open Source Tool for Fighting Neglected Tropical Disease. ChemMedChem 2019; 14:386-453. [PMID: 30614200 DOI: 10.1002/cmdc.201800755] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Indexed: 12/13/2022]
Abstract
The Pathogen Box is a 400-strong collection of drug-like compounds, selected for their potential against several of the world's most important neglected tropical diseases, including trypanosomiasis, leishmaniasis, cryptosporidiosis, toxoplasmosis, filariasis, schistosomiasis, dengue virus and trichuriasis, in addition to malaria and tuberculosis. This library represents an ensemble of numerous successful drug discovery programmes from around the globe, aimed at providing a powerful resource to stimulate open source drug discovery for diseases threatening the most vulnerable communities in the world. This review seeks to provide an in-depth analysis of the literature pertaining to the compounds in the Pathogen Box, including structure-activity relationship highlights, mechanisms of action, related compounds with reported activity against different diseases, and, where appropriate, discussion on the known and putative targets of compounds, thereby providing context and increasing the accessibility of the Pathogen Box to the drug discovery community.
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Affiliation(s)
- Clinton G L Veale
- School of Chemistry and Physics, Pietermaritzburg Campus, University of KwaZulu-Natal, Private Bag X01, Scottsville, 3209, South Africa
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17
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Saha SJ, Siddiqui AA, Pramanik S, Saha D, De R, Mazumder S, Debsharma S, Nag S, Banerjee C, Bandyopadhyay U. Hydrazonophenol, a Food Vacuole-Targeted and Ferriprotoporphyrin IX-Interacting Chemotype Prevents Drug-Resistant Malaria. ACS Infect Dis 2019; 5:63-73. [PMID: 30472841 DOI: 10.1021/acsinfecdis.8b00178] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The rapid emergence of resistance against frontline antimalarial drugs essentially warrants the identification of new-generation antimalarials. Here, we describe the synthesis of ( E)-2-isopropyl-5-methyl-4-((2-(pyridin-4-yl)hydrazono)methyl)phenol (18), which binds ferriprotoporphyrin-IX (FeIII-PPIX) ( Kd = 33 nM) and offers antimalarial activity against chloroquine-resistant and sensitive strains of Plasmodium falciparum in vitro. Structure-function analysis reveals that compound 18 binds FeIII-PPIX through the -C═N-NH- moiety and 2-pyridyl substitution at the hydrazine counterpart plays a critical role in antimalarial efficacy. Live cell confocal imaging using a fluorophore-tagged compound confirms its accumulation inside the acidic food vacuole (FV) of P. falciparum. Furthermore, this compound concentration-dependently elevates the pH in FV, implicating a plausible interference with FeIII-PPIX crystallization (hemozoin formation) by a dual function: increasing the pH and binding free FeIII-PPIX. Different off-target bioassays reduce the possibility of the promiscuous nature of compound 18. Compound 18 also exhibits potent in vivo antimalarial activity against chloroquine-resistant P. yoelii and P. berghei ANKA (causing cerebral malaria) in mice with negligible toxicity.
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Affiliation(s)
- Shubhra Jyoti Saha
- Division of Infectious Diseases and Immunology, CSIR - Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Asim Azhar Siddiqui
- Division of Infectious Diseases and Immunology, CSIR - Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Saikat Pramanik
- Division of Infectious Diseases and Immunology, CSIR - Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Debanjan Saha
- Division of Infectious Diseases and Immunology, CSIR - Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Rudranil De
- Division of Infectious Diseases and Immunology, CSIR - Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Somnath Mazumder
- Division of Infectious Diseases and Immunology, CSIR - Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Subhashis Debsharma
- Division of Infectious Diseases and Immunology, CSIR - Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Shiladitya Nag
- Division of Infectious Diseases and Immunology, CSIR - Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Chinmoy Banerjee
- Division of Infectious Diseases and Immunology, CSIR - Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Uday Bandyopadhyay
- Division of Infectious Diseases and Immunology, CSIR - Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
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18
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Synthesis, antimalarial, antiproliferative, and apoptotic activities of benzimidazole-5-carboxamide derivatives. Med Chem Res 2018. [DOI: 10.1007/s00044-018-2258-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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19
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L'abbate FP, Müller R, Openshaw R, Combrinck JM, de Villiers KA, Hunter R, Egan TJ. Hemozoin inhibiting 2-phenylbenzimidazoles active against malaria parasites. Eur J Med Chem 2018; 159:243-254. [PMID: 30296683 DOI: 10.1016/j.ejmech.2018.09.060] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 09/22/2018] [Accepted: 09/24/2018] [Indexed: 12/23/2022]
Abstract
The 2-phenylbenzimidazole scaffold has recently been discovered to inhibit β-hematin (synthetic hemozoin) formation by high throughput screening. Here, a library of 325,728 N-4-(1H-benzo[d]imidazol-2-yl)aryl)benzamides was enumerated, and Bayesian statistics used to predict β-hematin and Plasmodium falciparum growth inhibition. Filtering predicted inactives and compounds with negligible aqueous solubility reduced the library to 35,124. Further narrowing to compounds with terminal aryl ring substituents only, reduced the library to 18, 83% of which were found to inhibit β-hematin formation <100 μM and 50% parasite growth <2 μM. Four compounds showed nanomolar parasite growth inhibition activities, no cross-resistance in a chloroquine resistant strain and low cytotoxicity. QSAR analysis showed a strong association of parasite growth inhibition with inhibition of β-hematin formation and the most active compound inhibited hemozoin formation in P. falciparum, with consequent increasing exchangeable heme. Pioneering use of molecular docking for this system demonstrated predictive ability and could rationalize observed structure activity trends.
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Affiliation(s)
- Fabrizio P L'abbate
- Department of Chemistry, University of Cape Town, Rondebosch, 7701, South Africa
| | - Ronel Müller
- Department of Chemistry and Polymer Science, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Roxanne Openshaw
- Department of Chemistry, University of Cape Town, Rondebosch, 7701, South Africa
| | - Jill M Combrinck
- Department of Medicine, Division of Clinical Pharmacology, University of Cape Town, Observatory, 7925, South Africa
| | - Katherine A de Villiers
- Department of Chemistry and Polymer Science, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Roger Hunter
- Department of Chemistry, University of Cape Town, Rondebosch, 7701, South Africa
| | - Timothy J Egan
- Department of Chemistry, University of Cape Town, Rondebosch, 7701, South Africa; Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch, 7701, South Africa.
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20
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Fitzroy SM, Gildenhuys J, Olivier T, Tshililo NO, Kuter D, de Villiers KA. The Effects of Quinoline and Non-Quinoline Inhibitors on the Kinetics of Lipid-Mediated β-Hematin Crystallization. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:7529-7537. [PMID: 28689414 PMCID: PMC5709178 DOI: 10.1021/acs.langmuir.7b01132] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The throughput of a biomimetic lipid-mediated assay used to investigate the effects of inhibitors on the kinetics of β-hematin formation has been optimized through the use of 24-well microplates. The rate constant for β-hematin formation mediated by monopalmitoyl-rac-glycerol was reduced from 0.17 ± 0.04 min-1 previously measured in Falcon tubes to 0.019 ± 0.002 min-1 in the optimized assay. While this necessitated longer incubation times, transferring aliquots from multiple 24-well plates to a single 96-well plate for final absorbance measurements actually improved the overall turnaround time per inhibitor. This assay has been applied to investigate the effects of four clinically relevant antimalarial drugs (chloroquine, amodiaquine, quinidine, and quinine) as well as several short-chain 4-aminoquinoline derivatives and non-quinoline (benzamide) compounds on the kinetics of β-hematin formation. The adsorption strength of these inhibitors to crystalline β-hematin (Kads) was quantified using a theoretical kinetic model that is based on the Avrami equation and the Langmuir isotherm. Statistically significant linear correlations between lipid-mediated β-hematin inhibitory activity and Kads values for quinoline (r2 = 0.76, P-value = 0.0046) and non-quinoline compounds (r2 = 0.99, P-stat = 0.0006), as well as between parasite inhibitory activity (D10) and Kads values for quinoline antimalarial drugs and short-chain chloroquine derivatives (r2 = 0.64, P-value = 0.0098), provide a strong indication that drug action involves adsorption to the surface of β-hematin crystals. Independent support in this regard is provided by experiments that spectrophotometrically monitor the direct adsorption of antimalarial drugs to preformed β-hematin.
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21
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Okombo J, Chibale K. Insights into Integrated Lead Generation and Target Identification in Malaria and Tuberculosis Drug Discovery. Acc Chem Res 2017. [PMID: 28636311 PMCID: PMC5518282 DOI: 10.1021/acs.accounts.6b00631] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
New, safe and effective drugs are urgently needed to treat and control malaria and tuberculosis, which affect millions of people annually. However, financial return on investment in the poor settings where these diseases are mostly prevalent is very minimal to support market-driven drug discovery and development. Moreover, the imminent loss of therapeutic lifespan of existing therapies due to evolution and spread of drug resistance further compounds the urgency to identify novel effective drugs. However, the advent of new public-private partnerships focused on tropical diseases and the recent release of large data sets by pharmaceutical companies on antimalarial and antituberculosis compounds derived from phenotypic whole cell high throughput screening have spurred renewed interest and opened new frontiers in malaria and tuberculosis drug discovery. This Account recaps the existing challenges facing antimalarial and antituberculosis drug discovery, including limitations associated with experimental animal models as well as biological complexities intrinsic to the causative pathogens. We enlist various highlights from a body of work within our research group aimed at identifying and characterizing new chemical leads, and navigating these challenges to contribute toward the global drug discovery and development pipeline in malaria and tuberculosis. We describe a catalogue of in-house efforts toward deriving safe and efficacious preclinical drug development candidates via cell-based medicinal chemistry optimization of phenotypic whole-cell medium and high throughput screening hits sourced from various small molecule chemical libraries. We also provide an appraisal of target-based screening, as invoked in our laboratory for mechanistic evaluation of the hits generated, with particular focus on the enzymes within the de novo pyrimidine biosynthetic and hemoglobin degradation pathways, the latter constituting a heme detoxification process and an associated cysteine protease-mediated hydrolysis of hemoglobin. We further expound on the recombinant enzyme assays, heme fractionation experiments, and genomic and chemoproteomic methods that we employed to identify Plasmodium falciparum falcipain 2 (PfFP2), hemozoin formation, phosphatidylinositol 4-kinase (PfPI4K) and Mycobacterium tuberculosis cytochrome bc1 complex as the targets of the antimalarial chalcones, pyrido[1,2-a]benzimidazoles, aminopyridines, and antimycobacterial pyrrolo[3,4-c]pyridine-1,3(2H)-diones, respectively. In conclusion, we argue for the expansion of chemical space through exploitation of privileged natural product scaffolds and diversity-oriented synthesis, as well as the broadening of druggable spaces by exploiting available protein crystal structures, -omics data, and bioinformatics infrastructure to explore hitherto untargeted spaces like lipid metabolism and protein kinases in P. falciparum. Finally, we audit the merits of both target-based and whole-cell phenotypic screening in steering antimalarial and antituberculosis chemical matter toward populating drug discovery pipelines with new lead molecules.
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Affiliation(s)
- John Okombo
- Department
of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - Kelly Chibale
- Department
of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
- South
African Medical Research Council Drug Discovery and Development Research
Unit, Drug Discovery and Development Centre (H3D), Department of Chemistry
and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch 7701, South Africa
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22
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Wicht KJ, Combrinck JM, Smith PJ, Hunter R, Egan TJ. Identification and Mechanistic Evaluation of Hemozoin-Inhibiting Triarylimidazoles Active against Plasmodium falciparum. ACS Med Chem Lett 2017; 8:201-205. [PMID: 28197312 DOI: 10.1021/acsmedchemlett.6b00416] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 01/24/2017] [Indexed: 11/28/2022] Open
Abstract
In a previous study, target based screening was carried out for inhibitors of β-hematin (synthetic hemozoin) formation, and a series of triarylimidazoles were identified as active against Plasmodium falciparum. Here, we report the subsequent synthesis and testing of derivatives with varying substituents on the three phenyl rings for this series. The results indicated that a 2-hydroxy-1,3-dimethoxy substitution pattern on ring A is required for submicromolar parasite activity. In addition, cell-fractionation studies revealed uncommonly large, dose-dependent increases of P. falciparum intracellular exchangeable (free) heme, correlating with decreased parasite survival for β-hematin inhibiting derivatives.
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Affiliation(s)
- Kathryn J. Wicht
- Department
of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - Jill M. Combrinck
- Division
of Pharmacology, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Observatory 7925, South Africa
| | - Peter J. Smith
- Division
of Pharmacology, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Observatory 7925, South Africa
| | - Roger Hunter
- Department
of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - Timothy J. Egan
- Department
of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
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23
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Singh K, Okombo J, Brunschwig C, Ndubi F, Barnard L, Wilkinson C, Njogu PM, Njoroge M, Laing L, Machado M, Prudêncio M, Reader J, Botha M, Nondaba S, Birkholtz LM, Lauterbach S, Churchyard A, Coetzer TL, Burrows JN, Yeates C, Denti P, Wiesner L, Egan TJ, Wittlin S, Chibale K. Antimalarial Pyrido[1,2-a]benzimidazoles: Lead Optimization, Parasite Life Cycle Stage Profile, Mechanistic Evaluation, Killing Kinetics, and in Vivo Oral Efficacy in a Mouse Model. J Med Chem 2017; 60:1432-1448. [DOI: 10.1021/acs.jmedchem.6b01641] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Kawaljit Singh
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
- South African Medical Research Council Drug Discovery and Development Research Unit, Department of Chemistry
and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch 7701, South Africa
| | - John Okombo
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - Christel Brunschwig
- Department of Medicine, Division of Clinical Pharmacology, University of Cape Town, Observatory, 7925, South Africa
| | - Ferdinand Ndubi
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - Linley Barnard
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - Chad Wilkinson
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - Peter M. Njogu
- Department of Pharmaceutical Chemistry, University of Nairobi, P.O. Box 19676, Nairobi, 00202, Kenya
| | - Mathew Njoroge
- Department of Medicine, Division of Clinical Pharmacology, University of Cape Town, Observatory, 7925, South Africa
| | - Lizahn Laing
- Department of Medicine, Division of Clinical Pharmacology, University of Cape Town, Observatory, 7925, South Africa
| | - Marta Machado
- Instituto de Medicina Molecular, Faculdade
de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Miguel Prudêncio
- Instituto de Medicina Molecular, Faculdade
de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Janette Reader
- Department of Biochemistry, Institute for Sustainable
Malaria Control, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Mariette Botha
- Department of Biochemistry, Institute for Sustainable
Malaria Control, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Sindisiwe Nondaba
- Department of Biochemistry, Institute for Sustainable
Malaria Control, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Lyn-Marie Birkholtz
- Department of Biochemistry, Institute for Sustainable
Malaria Control, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Sonja Lauterbach
- Wits Research Institute for Malaria, Faculty
of Health Sciences, University of the Witwatersrand and National Health Laboratory Service, Johannesburg 2193, South Africa
| | - Alisje Churchyard
- Wits Research Institute for Malaria, Faculty
of Health Sciences, University of the Witwatersrand and National Health Laboratory Service, Johannesburg 2193, South Africa
| | - Theresa L. Coetzer
- Wits Research Institute for Malaria, Faculty
of Health Sciences, University of the Witwatersrand and National Health Laboratory Service, Johannesburg 2193, South Africa
| | - Jeremy N. Burrows
- Medicines for Malaria Venture, ICC, Route de Pré-Bois 20, P.O. Box 1826, 1215 Geneva, Switzerland
| | - Clive Yeates
- Inpharma Consultancy, 6 Dudley Hill Close, Welwyn, Hertfordshire AL60QQ, U.K
| | - Paolo Denti
- Department of Medicine, Division of Clinical Pharmacology, University of Cape Town, Observatory, 7925, South Africa
| | - Lubbe Wiesner
- Department of Medicine, Division of Clinical Pharmacology, University of Cape Town, Observatory, 7925, South Africa
| | - Timothy J. Egan
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - Sergio Wittlin
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002 Basel, Switzerland
- University of Basel, 4003 Basel, Switzerland
| | - Kelly Chibale
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
- South African Medical Research Council Drug Discovery and Development Research Unit, Department of Chemistry
and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch 7701, South Africa
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