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Greyling N, van der Watt M, Gwarinda H, van Heerden A, Greenhouse B, Leroy D, Niemand J, Birkholtz LM. Genetic complexity alters drug susceptibility of asexual and gametocyte stages of Plasmodium falciparum to antimalarial candidates. Antimicrob Agents Chemother 2024; 68:e0129123. [PMID: 38259087 PMCID: PMC10916389 DOI: 10.1128/aac.01291-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 12/06/2023] [Indexed: 01/24/2024] Open
Abstract
Malaria elimination requires interventions able to target both the asexual blood stage (ABS) parasites and transmissible gametocyte stages of Plasmodium falciparum. Lead antimalarial candidates are evaluated against clinical isolates to address key concerns regarding efficacy and to confirm that the current, circulating parasites from endemic regions lack resistance against these candidates. While this has largely been performed on ABS parasites, limited data are available on the transmission-blocking efficacy of compounds with multistage activity. Here, we evaluated the efficacy of lead antimalarial candidates against both ABS parasites and late-stage gametocytes side-by-side, against clinical P. falciparum isolates from southern Africa. We additionally correlated drug efficacy to the genetic diversity of the clinical isolates as determined with a panel of well-characterized, genome-spanning microsatellite markers. Our data indicate varying sensitivities of the isolates to key antimalarial candidates, both for ABS parasites and gametocyte stages. While ABS parasites were efficiently killed, irrespective of genetic complexity, antimalarial candidates lost some gametocytocidal efficacy when the gametocytes originated from genetically complex, multiple-clone infections. This suggests a fitness benefit to multiclone isolates to sustain transmission and reduce drug susceptibility. In conclusion, this is the first study to investigate the efficacy of antimalarial candidates on both ABS parasites and gametocytes from P. falciparum clinical isolates where the influence of parasite genetic complexity is highlighted, ultimately aiding the malaria elimination agenda.
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Affiliation(s)
- Nicola Greyling
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | - Mariëtte van der Watt
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | - Hazel Gwarinda
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | - Ashleigh van Heerden
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | - Bryan Greenhouse
- Department of Medicine, University of California-San Francisco, San Francisco, California, USA
| | - Didier Leroy
- Medicines for Malaria Venture, Geneva, Switzerland
| | - Jandeli Niemand
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | - Lyn-Marié Birkholtz
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
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2
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Watson DJ, Laing L, Petzer JP, Wong HN, Parkinson CJ, Wiesner L, Haynes RK. Efficacies and ADME properties of redox active methylene blue and phenoxazine analogues for use in new antimalarial triple drug combinations with amino-artemisinins. Front Pharmacol 2024; 14:1308400. [PMID: 38259296 PMCID: PMC10800708 DOI: 10.3389/fphar.2023.1308400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 12/11/2023] [Indexed: 01/24/2024] Open
Abstract
Efforts to develop new artemisinin triple combination therapies effective against artemisinin-tolerant strains of Plasmodium falciparum based on rational combinations comprising artemisone or other amino-artemisinins, a redox active drug and a third drug with a different mode of action have now been extended to evaluation of three potential redox partners. These are the diethyl analogue AD01 of methylene blue (MB), the benzo [α]phenoxazine PhX6, and the thiosemicarbazone DpNEt. IC50 values in vitro against CQ-sensitive and resistant P. falciparum strains ranged from 11.9 nM for AD01-41.8 nM for PhX6. PhX6 possessed the most favourable pharmacokinetic (PK) profile: intrinsic clearance rate CLint was 21.47 ± 1.76 mL/min/kg, bioavailability was 60% and half-life was 7.96 h. AD01 presented weaker, but manageable pharmacokinetic properties with a rapid CLint of 74.41 ± 6.68 mL/min/kg leading to a half-life of 2.51 ± 0.07 h and bioavailability of 15%. DpNEt exhibited a half-life of 1.12 h and bioavailability of 8%, data which discourage its further examination, despite a low CLint of 10.20 mL/min/kg and a high Cmax of 6.32 µM. Efficacies of AD01 and PhX6 were enhanced synergistically when each was paired with artemisone against asexual blood stages of P. falciparum NF54 in vitro. The favourable pharmacokinetics of PhX6 indicate this is the best partner among the compounds examined thus far for artemisone. Future work will focus on extending the drug combination studies to artemiside in vitro, and conducting efficacy studies in vivo for artemisone with each of PhX6 and the related benzo[α]phenoxazine SSJ-183.
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Affiliation(s)
- Daniel J. Watson
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Lizahn Laing
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Jacobus P. Petzer
- Centre of Excellence for Pharmaceutical Sciences, Faculty of Health Sciences, North-West University, Potchefstroom, South Africa
| | - Ho Ning Wong
- Rural Health Research Institute, Charles Sturt University, Orange, NSW, Australia
| | | | - Lubbe Wiesner
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Richard K. Haynes
- Centre of Excellence for Pharmaceutical Sciences, Faculty of Health Sciences, North-West University, Potchefstroom, South Africa
- Rural Health Research Institute, Charles Sturt University, Orange, NSW, Australia
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3
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Schlange C, Müller J, Imhof D, Hänggeli KPA, Boubaker G, Ortega-Mora LM, Wong HN, Haynes RK, Van Voorhis WC, Hemphill A. Single and combination treatment of Toxoplasma gondii infections with a bumped kinase inhibitor and artemisone in vitro and with artemiside in experimentally infected mice. Exp Parasitol 2023; 255:108655. [PMID: 37981259 DOI: 10.1016/j.exppara.2023.108655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 11/01/2023] [Accepted: 11/13/2023] [Indexed: 11/21/2023]
Abstract
In previous studies, the artemisinin derivatives artemisone, its pro-drug artemiside and the bumped-kinase inhibitor BKI-1748 were effective against T. gondii via different modes of action. This suggests that they may act synergistically resulting in improved efficacies in vitro and in vivo. To test this hypothesis, the compounds were applied alone and in combination to T. gondii infected human fibroblast host cells in order to determine their inhibition constants and effects on cellular ultrastructure. In addition, the efficacy of either single- or combined treatments were assessed in an acute TgShSp1-oocyst infection model based on CD1 outbred mice. Whereas the IC50 of the compounds in combination (42 nM) was close to the IC50 of BKI-1748 alone (46 nM) and half of the IC50 of artemisone alone (92 nM), the IC90 of the combination was half of the values found with the single compounds (138 nM vs. ca. 270 nM). Another indication for synergistic effects in vitro were distinct alterations of the cellular ultrastructure of tachyzoites observed in combination, but not with the single compounds. These promising results could not be reproduced in vivo. There was no decrease in number of T. gondii positive brains by either treatment. However, the levels of infection in these brains, i. e. the number of tachyzoites, was significantly decreased upon BKI-1748 treatment alone, and the combination with artemiside did not produce any further decrease. The treatment with artemiside alone had no significant effects. A vertical transmission model could not be established since artemiside strongly interfered with pregnancy and caused abortion. These results show that is difficult to extrapolate from promising in vitro results to the situation in vivo.
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Affiliation(s)
- Carling Schlange
- Institute of Parasitology, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Länggass-Strasse 122, CH-3012, Bern, Switzerland
| | - Joachim Müller
- Institute of Parasitology, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Länggass-Strasse 122, CH-3012, Bern, Switzerland
| | - Dennis Imhof
- Institute of Parasitology, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Länggass-Strasse 122, CH-3012, Bern, Switzerland
| | - Kai Pascal Alexander Hänggeli
- Institute of Parasitology, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Länggass-Strasse 122, CH-3012, Bern, Switzerland
| | - Ghalia Boubaker
- Institute of Parasitology, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Länggass-Strasse 122, CH-3012, Bern, Switzerland
| | - Luis-Miguel Ortega-Mora
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria S/n, 28040, Madrid, Spain
| | - Ho Ning Wong
- Rural Health Research Institute, Charles Sturt University, Orange, New South Wales, 2800, Australia
| | - Richard K Haynes
- Rural Health Research Institute, Charles Sturt University, Orange, New South Wales, 2800, Australia; Centre of Excellence for Pharmaceutical Sciences, Faculty of Health Sciences, North-West University, Potchefstroom, 2520, South Africa
| | - Wesley C Van Voorhis
- Center for Emerging and Re-emerging Infectious Diseases (CERID), Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
| | - Andrew Hemphill
- Institute of Parasitology, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Länggass-Strasse 122, CH-3012, Bern, Switzerland.
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4
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Umumararungu T, Nkuranga JB, Habarurema G, Nyandwi JB, Mukazayire MJ, Mukiza J, Muganga R, Hahirwa I, Mpenda M, Katembezi AN, Olawode EO, Kayitare E, Kayumba PC. Recent developments in antimalarial drug discovery. Bioorg Med Chem 2023; 88-89:117339. [PMID: 37236020 DOI: 10.1016/j.bmc.2023.117339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/12/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023]
Abstract
Although malaria remains a big burden to many countries that it threatens their socio-economic stability, particularly in the countries where malaria is endemic, there have been great efforts to eradicate this disease with both successes and failures. For example, there has been a great improvement in malaria prevention and treatment methods with a net reduction in infection and mortality rates. However, the disease remains a global threat in terms of the number of people affected because it is one of the infectious diseases that has the highest prevalence rate, especially in Africa where the deadly Plasmodium falciparum is still widely spread. Methods to fight malaria are being diversified, including the use of mosquito nets, the target candidate profiles (TCPs) and target product profiles (TPPs) of medicine for malarial venture (MMV) strategy, the search for newer and potent drugs that could reverse chloroquine resistance, and the use of adjuvants such as rosiglitazone and sevuparin. Although these adjuvants have no antiplasmodial activity, they can help to alleviate the effects which result from plasmodium invasion such as cytoadherence. The list of new antimalarial drugs under development is long, including the out of ordinary new drugs MMV048, CDRI-97/78 and INE963 from South Africa, India and Novartis, respectively.
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Affiliation(s)
- Théoneste Umumararungu
- Department of Pharmacy, School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Rwanda.
| | - Jean Bosco Nkuranga
- Department of Chemistry, School of Science, College of Science and Technology, University of Rwanda, Rwanda
| | - Gratien Habarurema
- Department of Chemistry, School of Science, College of Science and Technology, University of Rwanda, Rwanda
| | - Jean Baptiste Nyandwi
- Department of Pharmacy, School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Rwanda
| | - Marie Jeanne Mukazayire
- Department of Pharmacy, School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Rwanda
| | - Janvier Mukiza
- Department of Mathematical Science and Physical Education, School of Education, College of Education, University of Rwanda, Rwanda; Rwanda Food and Drugs Authority, Nyarutarama Plaza, KG 9 Avenue, Kigali, Rwanda
| | - Raymond Muganga
- Department of Pharmacy, School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Rwanda; Rwanda Food and Drugs Authority, Nyarutarama Plaza, KG 9 Avenue, Kigali, Rwanda
| | - Innocent Hahirwa
- Department of Pharmacy, School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Rwanda
| | - Matabishi Mpenda
- Department of Pharmacy, School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Rwanda
| | - Alain Nyirimigabo Katembezi
- Department of Pharmacy, School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Rwanda; Rwanda Food and Drugs Authority, Nyarutarama Plaza, KG 9 Avenue, Kigali, Rwanda
| | - Emmanuel Oladayo Olawode
- Department of Pharmaceutical Sciences, College of Pharmacy, Larkin University, 18301 N Miami Ave #1, Miami, FL 33169, USA
| | - Egide Kayitare
- Department of Pharmacy, School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Rwanda
| | - Pierre Claver Kayumba
- Department of Pharmacy, School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Rwanda
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5
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Müller J, Schlange C, Heller M, Uldry AC, Braga-Lagache S, Haynes RK, Hemphill A. Proteomic characterization of Toxoplasma gondii ME49 derived strains resistant to the artemisinin derivatives artemiside and artemisone implies potential mode of action independent of ROS formation. Int J Parasitol Drugs Drug Resist 2022; 21:1-12. [PMID: 36512904 PMCID: PMC9763631 DOI: 10.1016/j.ijpddr.2022.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 11/26/2022] [Accepted: 11/28/2022] [Indexed: 12/13/2022]
Abstract
The sesquiterpene lactone artemisinin and its amino-artemisinin derivatives artemiside (GC008) and artemisone (GC003) are potent antimalarials. The mode of action of artemisinins against Plasmodium sp is popularly ascribed to 'activation' of the peroxide group by heme-Fe(II) or labile Fe(II) to generate C-radicals that alkylate parasite proteins. An alternative postulate is that artemisinins elicit formation of reactive oxygen species by interfering with flavin disulfide reductases resposible for maintaining intraparasitic redox homeostasis. However, in contradistinction to the heme-activation mechanism, the amino-artemisinins are effective in vitro against non-heme-degrading apicomplexan parasites including T. gondii, with IC 50 values of 50-70 nM, and induce distinct ultrastructural alterations. However, T. gondii strains readily adapted to increased concentrations (2.5 μM) of these two compounds within few days. Thus, T. gondii strains that were resistant against artemisone and artemiside were generated by treating the T. gondii reference strain ME49 with stepwise increasing amounts of these compounds, yielding the artemisone resistant strain GC003R and the artemiside resistant strain GC008R. Differential analyses of the proteomes of these resistant strains compared to the wildtype ME49 revealed that 215 proteins were significantly downregulated in artemisone resistant tachyzoites and only 8 proteins in artemiside resistant tachyzoites as compared to their wildtype. Two proteins, namely a hypothetical protein encoded by ORF TGME49_236950, and the rhoptry neck protein RON2 encoded by ORF TGME49_300100 were downregulated in both resistant strains. Interestingly, eight proteins involved in ROS scavenging including catalase and superoxide dismutase were amongst the differentially downregulated proteins in the artemisone-resistant strain. In parallel, ROS formation was significantly enhanced in isolated tachyzoites from the artemisone resistant strain and - to a lesser extent - in tachyzoites from the artemiside resistant strain as compared to wildtype tachyzoites. These findings suggest that amino-artemisinin derivatives display a mechanism of action in T. gondii distinct from Plasmodium.
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Affiliation(s)
- Joachim Müller
- Institute of Parasitology, University of Bern, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, Länggass-Strasse 122, CH-3012, Bern, Switzerland
| | - Carling Schlange
- Institute of Parasitology, University of Bern, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, Länggass-Strasse 122, CH-3012, Bern, Switzerland
| | - Manfred Heller
- Proteomics & Mass Spectrometry Core Facility, Department for BioMedical Research (DBMR), University of Bern, Freiburgstrasse 15, CH-3010, Bern, Switzerland
| | - Anne-Christine Uldry
- Proteomics & Mass Spectrometry Core Facility, Department for BioMedical Research (DBMR), University of Bern, Freiburgstrasse 15, CH-3010, Bern, Switzerland
| | - Sophie Braga-Lagache
- Proteomics & Mass Spectrometry Core Facility, Department for BioMedical Research (DBMR), University of Bern, Freiburgstrasse 15, CH-3010, Bern, Switzerland
| | - Richard K Haynes
- Centre of Excellence for Pharmaceutical Sciences, Faculty of Health Sciences, North-West University, Potchefstroom, 2520, South Africa
| | - Andrew Hemphill
- Institute of Parasitology, University of Bern, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, Länggass-Strasse 122, CH-3012, Bern, Switzerland.
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Reader J, Opperman DFL, van der Watt ME, Theron A, Leshabane M, da Rocha S, Turner J, Garrabrant K, Piña I, Mills C, Woster PM, Birkholtz L. New Transmission-Selective Antimalarial Agents through Hit-to-Lead Optimization of 2-([1,1'-Biphenyl]-4-carboxamido)benzoic Acid Derivatives. Chembiochem 2022; 23:e202200427. [PMID: 36106425 PMCID: PMC10946866 DOI: 10.1002/cbic.202200427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 09/14/2022] [Indexed: 11/12/2022]
Abstract
Malaria elimination requires multipronged approaches, including the application of antimalarial drugs able to block human-to-mosquito transmission of malaria parasites. The transmissible gametocytes of Plasmodium falciparum seem to be highly sensitive towards epidrugs, particularly those targeting demethylation of histone post-translational marks. Here, we report exploration of compounds from a chemical library generated during hit-to-lead optimization of inhibitors of the human histone lysine demethylase, KDM4B. Derivatives of 2-([1,1'-biphenyl]-4-carboxamido) benzoic acid, around either the amide or a sulfonamide linker backbone (2-(arylcarboxamido)benzoic acid, 2-carboxamide (arylsulfonamido)benzoic acid and N-(2-(1H-tetrazol-5-yl)phenyl)-arylcarboxamide), showed potent activity towards late-stage gametocytes (stage IV/V) of P. falciparum, with the most potent compound reaching single digit nanomolar activity. Structure-activity relationship trends were evident and frontrunner compounds also displayed microsomal stability and favourable solubility profiles. Simplified synthetic routes support further derivatization of these compounds for further development of these series as malaria transmission-blocking agents.
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Affiliation(s)
- Janette Reader
- Department of BiochemistryGenetics and MicrobiologyInstitute for Sustainable Malaria ControlUniversity of PretoriaLynnwood RoadPretoria0028South Africa
| | - Daniel F. L. Opperman
- Department of BiochemistryGenetics and MicrobiologyInstitute for Sustainable Malaria ControlUniversity of PretoriaLynnwood RoadPretoria0028South Africa
| | - Mariëtte E. van der Watt
- Department of BiochemistryGenetics and MicrobiologyInstitute for Sustainable Malaria ControlUniversity of PretoriaLynnwood RoadPretoria0028South Africa
- School of Health Systems and Public HealthUniversity of Pretoria, HatfieldPretoria0028South Africa
| | - Anjo Theron
- Next Generation HealthCouncil for Scientific and Industrial ResearchPretoria0001South Africa
| | - Meta Leshabane
- Department of BiochemistryGenetics and MicrobiologyInstitute for Sustainable Malaria ControlUniversity of PretoriaLynnwood RoadPretoria0028South Africa
| | - Shanté da Rocha
- Department of BiochemistryGenetics and MicrobiologyInstitute for Sustainable Malaria ControlUniversity of PretoriaLynnwood RoadPretoria0028South Africa
| | - Jonathan Turner
- Department of Drug Discovery and Biomedical SciencesMedical University of South CarolinaCharlestonSC 29425USA
| | - Kathleen Garrabrant
- Department of Drug Discovery and Biomedical SciencesMedical University of South CarolinaCharlestonSC 29425USA
| | - Ivett Piña
- Department of Drug Discovery and Biomedical SciencesMedical University of South CarolinaCharlestonSC 29425USA
| | - Catherine Mills
- Department of Drug Discovery and Biomedical SciencesMedical University of South CarolinaCharlestonSC 29425USA
| | - Patrick M. Woster
- Department of Drug Discovery and Biomedical SciencesMedical University of South CarolinaCharlestonSC 29425USA
| | - Lyn‐Marié Birkholtz
- Department of BiochemistryGenetics and MicrobiologyInstitute for Sustainable Malaria ControlUniversity of PretoriaLynnwood RoadPretoria0028South Africa
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7
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Ng JPL, Han Y, Yang LJ, Birkholtz LM, Coertzen D, Wong HN, Haynes RK, Coghi P, Wong VKW. Antimalarial and antitumour activities of the steroidal quinone-methide celastrol and its combinations with artemiside, artemisone and methylene blue. Front Pharmacol 2022; 13:988748. [PMID: 36120293 PMCID: PMC9479156 DOI: 10.3389/fphar.2022.988748] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 08/08/2022] [Indexed: 11/19/2022] Open
Abstract
Artemisinin, isolated from the traditional Chinese medicinal plant qīng hāo 青蒿 (Artemisia annua) and its derivatives are used for treatment of malaria. With treatment failures now being recorded for the derivatives and companion drugs used in artemisinin combination therapies new drug combinations are urgently required. The amino-artemisinins artemiside and artemisone display optimal efficacies in vitro against asexual and sexual blood stages of the malaria parasite Plasmodium falciparum and are active against tumour cell lines. In continuing the evolution of combinations of the amino-artemisinins with new drugs, we examine the triterpenoid quinone methide celastrol isolated from the traditional Chinese medicinal plant léi gōng téng 雷公藤 (Tripterygium wilfordii). This compound is redox active, and has attracted considerable attention because of potent biological activities against manifold targets. We report that celastrol displays good IC50 activities ranging from 0.50–0.82 µM against drug-sensitive and resistant asexual blood stage Pf, and 1.16 and 0.28 µM respectively against immature and late stage Pf NF54 gametocytes. The combinations of celastrol with each of artemisone and methylene blue against asexual blood stage Pf are additive. Given that celastrol displays promising antitumour properties, we examined its activities alone and in combinations with amino-artemisinins against human liver HepG2 and other cell lines. IC50 values of the amino-artemisinins and celastrol against HepG2 cancer cells ranged from 0.55–0.94 µM. Whereas the amino-artemisinins displayed notable selectivities (SI > 171) with respect to normal human hepatocytes, in contrast, celastrol displayed no selectivity (SI < 1). The combinations of celastrol with artemiside or artemisone against HepG2 cells are synergistic. Given the promise of celastrol, judiciously designed formulations or structural modifications are recommended for mitigating its toxicity.
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Affiliation(s)
- Jerome P. L. Ng
- Neher’s Biophysics Laboratory for Innovative Drug Discovery, State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Macau, China
| | - Yu Han
- Neher’s Biophysics Laboratory for Innovative Drug Discovery, State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Macau, China
| | - Li Jun Yang
- Neher’s Biophysics Laboratory for Innovative Drug Discovery, State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Macau, China
| | - Lyn-Marie Birkholtz
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria Institute Malaria for Sustainable Malaria Control, University of Pretoria, Hatfield, South Africa
| | - Dina Coertzen
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria Institute Malaria for Sustainable Malaria Control, University of Pretoria, Hatfield, South Africa
| | - Ho Ning Wong
- Centre of Excellence for Pharmaceutical Sciences, School of Health Sciences, North-West University, Potchefstroom, South Africa
| | - Richard K. Haynes
- Centre of Excellence for Pharmaceutical Sciences, School of Health Sciences, North-West University, Potchefstroom, South Africa
- *Correspondence: Richard K. Haynes, Paolo Coghi, Vincent Kam Wai Wong,
| | - Paolo Coghi
- School of Pharmacy, Macau University of Science and Technology, Macau, China
- *Correspondence: Richard K. Haynes, Paolo Coghi, Vincent Kam Wai Wong,
| | - Vincent Kam Wai Wong
- Neher’s Biophysics Laboratory for Innovative Drug Discovery, State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Macau, China
- *Correspondence: Richard K. Haynes, Paolo Coghi, Vincent Kam Wai Wong,
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8
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Muema JM, Bargul JL, Obonyo MA, Njeru SN, Matoke-Muhia D, Mutunga JM. Contemporary exploitation of natural products for arthropod-borne pathogen transmission-blocking interventions. Parasit Vectors 2022; 15:298. [PMID: 36002857 PMCID: PMC9404607 DOI: 10.1186/s13071-022-05367-8] [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: 02/24/2022] [Accepted: 06/16/2022] [Indexed: 11/26/2022] Open
Abstract
An integrated approach to innovatively counter the transmission of various arthropod-borne diseases to humans would benefit from strategies that sustainably limit onward passage of infective life cycle stages of pathogens and parasites to the insect vectors and vice versa. Aiming to accelerate the impetus towards a disease-free world amid the challenges posed by climate change, discovery, mindful exploitation and integration of active natural products in design of pathogen transmission-blocking interventions is of high priority. Herein, we provide a review of natural compounds endowed with blockade potential against transmissible forms of human pathogens reported in the last 2 decades from 2000 to 2021. Finally, we propose various translational strategies that can exploit these pathogen transmission-blocking natural products into design of novel and sustainable disease control interventions. In summary, tapping these compounds will potentially aid in integrated combat mission to reduce disease transmission trends.
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Affiliation(s)
- Jackson M Muema
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology (JKUAT), P.O. Box 62000, Nairobi, 00200, Kenya.
| | - Joel L Bargul
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology (JKUAT), P.O. Box 62000, Nairobi, 00200, Kenya.,International Centre of Insect Physiology and Ecology (Icipe), P.O. Box 30772, Nairobi, 00100, Kenya
| | - Meshack A Obonyo
- Department of Biochemistry and Molecular Biology, Egerton University, P.O. Box 536, Egerton, 20115, Kenya
| | - Sospeter N Njeru
- Centre for Traditional Medicine and Drug Research (CTMDR), Kenya Medical Research Institute (KEMRI), P.O. Box 54840, Nairobi, 00200, Kenya
| | - Damaris Matoke-Muhia
- Centre for Biotechnology Research Development (CBRD), Kenya Medical Research Institute (KEMRI), P.O. Box 54840, Nairobi, 00200, Kenya
| | - James M Mutunga
- Department of Biological Sciences, Mount Kenya University (MKU), P.O. Box 54, Thika, 01000, Kenya.,School of Engineering Design, Technology and Professional Programs, Pennsylvania State University, University Park, PA, 16802, USA
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9
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Watson DJ, Laing L, Beteck RM, Gibhard L, Haynes RK, Wiesner L. The evaluation of ADME and pharmacokinetic properties of decoquinate derivatives for the treatment of malaria. Front Pharmacol 2022; 13:957690. [PMID: 36091789 PMCID: PMC9450014 DOI: 10.3389/fphar.2022.957690] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 07/18/2022] [Indexed: 12/03/2022] Open
Abstract
The emergence of Plasmodium falciparum (Pf) parasite strains tolerant of the artemisinin component and resistant to the other drug component in artemisinin combination therapies (ACTs) used for treatment now markedly complicates malaria control. Thus, development of new combination therapies are urgently required. For the non-artemisinin component, the quinolone ester decoquinate (DQ) that possesses potent activities against blood stage Pf and acts on a distinct target, namely the Pf cytochrome bc1 complex, was first considered. However, DQ has poor drug properties including high lipophilicity and exceedingly poor aqueous solubility (0.06 μg/ml), rendering it difficult to administer. Thus, DQ was chemically modified to provide the secondary amide derivative RMB005 and the quinoline O-carbamate derivatives RMB059 and RMB060. The last possesses sub-nanomolar activities against multidrug resistant blood stages of Pf, and P. berghei sporozoite liver stages. Here we present the results of ADME analyses in vitro and pharmacokinetic analyses using C57BL/6 mice. The amide RMB005 had a maximum mean whole blood concentration of 0.49 ± 0.02 µM following oral administration; however, the area under the curve (AUC), elimination half-life (t1/2) and bioavailability (BA) were not significantly better than those of DQ. Surprisingly, the quinoline O-carbamates which can be recrystallized without decomposition were rapidly converted into DQ in human plasma and blood samples. The maximum concentrations of DQ reached after oral administration of RMB059 and RMB060 were 0.23 ± 0.05 and 0.11 ± 0.01 µM, the DQ elimination half-lives were 4.79 ± 1.66 and 4.66 ± 1.16 h, and the DQ clearance were 19.40 ± 3.14 and 21.50 ± 3.38 respectively. Under these assay conditions, the BA of DQ could not be calculated Overall although RMB059 and -060 are labile in physiological medium with respect to the DQ parent, the potential to apply these as prodrugs is apparent from the current data coupled with their ease of preparation.
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Affiliation(s)
- Daniel J. Watson
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Lizahn Laing
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Richard M. Beteck
- Centre of Excellence for Pharmaceutical Sciences, School of Health Sciences, North-West University, Potchefstroom, South Africa
| | - Liezl Gibhard
- Department of Chemistry, University of Cape Town, Cape Town, South Africa
| | - Richard K. Haynes
- Centre of Excellence for Pharmaceutical Sciences, School of Health Sciences, North-West University, Potchefstroom, South Africa
| | - Lubbe Wiesner
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
- *Correspondence: Lubbe Wiesner,
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10
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Reader J, van der Watt ME, Birkholtz LM. Streamlined and Robust Stage-Specific Profiling of Gametocytocidal Compounds Against Plasmodium falciparum. Front Cell Infect Microbiol 2022; 12:926460. [PMID: 35846744 PMCID: PMC9282888 DOI: 10.3389/fcimb.2022.926460] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 05/30/2022] [Indexed: 12/29/2022] Open
Abstract
Malaria elimination is dependent on the ability to target both the pathogenic and transmissible stages of the human malaria parasite, Plasmodium falciparum. These forms of the parasite are differentiated by unique developmental stages, each with their own biological mechanisms and processes. These individual stages therefore also respond differently to inhibitory compounds, and this complicates the discovery of multistage active antimalarial agents. The search for compounds with transmission-blocking activity has focused on screening for activity on mature gametocytes, with only limited descriptions available for the activity of such compounds on immature stage gametocytes. This therefore poses a gap in the profiling of antimalarial agents for pan-reactive, multistage activity to antimalarial leads. Here, we optimized an effective and robust strategy for the simple and cost-effective description of the stage-specific action of gametocytocidal antimalarial compounds.
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Affiliation(s)
- Janette Reader
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| | - Mariette E. van der Watt
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
| | - Lyn-Marié Birkholtz
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- *Correspondence: Lyn-Marié Birkholtz,
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11
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van der Watt ME, Reader J, Birkholtz LM. Adapt or Die: Targeting Unique Transmission-Stage Biology for Malaria Elimination. Front Cell Infect Microbiol 2022; 12:901971. [PMID: 35755845 PMCID: PMC9218253 DOI: 10.3389/fcimb.2022.901971] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 05/06/2022] [Indexed: 12/25/2022] Open
Abstract
Plasmodium parasites have a complex life cycle that includes development in the human host as well as the Anopheles vector. Successful transmission of the parasite between its host and vector therefore requires the parasite to balance its investments in asexual replication and sexual reproduction, varying the frequency of sexual commitment to persist within the human host and generate future opportunities for transmission. The transmission window is extended further by the ability of stage V gametocytes to circulate in peripheral blood for weeks, whereas immature stage I to IV gametocytes sequester in the bone marrow and spleen until final maturation. Due to the low gametocyte numbers in blood circulation and with the ease of targeting such life cycle bottlenecks, transmission represents an efficient target for therapeutic intervention. The biological process of Plasmodium transmission is a multistage, multifaceted process and the past decade has seen a much deeper understanding of the molecular mechanisms and regulators involved. Clearly, specific and divergent processes are used during transmission compared to asexual proliferation, which both poses challenges but also opportunities for discovery of transmission-blocking antimalarials. This review therefore presents an update of our molecular understanding of gametocyte and gamete biology as well as the status of transmission-blocking activities of current antimalarials and lead development compounds. By defining the biological components associated with transmission, considerations for the development of new transmission-blocking drugs to target such untapped but unique biology is suggested as an important, main driver for transmission-blocking drug discovery.
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Affiliation(s)
- Mariëtte E van der Watt
- Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
| | - Janette Reader
- Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa.,Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| | - Lyn-Marié Birkholtz
- Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa.,Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
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12
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In Vitro Activity of the Arylaminoartemisinin GC012 against Helicobacter pylori and Its Effects on Biofilm. Pathogens 2022; 11:pathogens11070740. [PMID: 35889986 PMCID: PMC9324866 DOI: 10.3390/pathogens11070740] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 06/20/2022] [Accepted: 06/27/2022] [Indexed: 12/17/2022] Open
Abstract
This study evaluated the in vitro activity of the arylaminoartemisinin GC012, readily obtained from dihydroartemisinin (DHA), against clinical strains of Helicobacter pylori (H. pylori) with different antibiotic susceptibilities in the planktonic and sessile state. The activity was assessed in terms of bacteriostatic and bactericidal potential. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by the broth microdilution method. After treatment with GC012, all bacterial strains showed significantly lower MIC and MBC values compared to those of DHA. The effect of combination of GC012 with antibiotics was examined using the checkerboard method. GC012 displayed synergistic interactions with metronidazole, clarithromycin, and amoxicillin in all the strains. The antibiofilm activity was evaluated via crystal violet staining, AlamarBlue® assay, colony-forming unit count, and fluorescence microscopy. At ½ MIC and ¼ MIC concentration, both GC012 and DHA inhibited biofilm formation, but only GC012 showed a minimal biofilm eradication concentration (MBEC) on mature biofilm. Furthermore, both compounds induced structural changes in the bacterial membrane, as observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). It is thereby demonstrated that GC012 has the potential to be efficacious against H. pylori infection.
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13
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Siddiqui G, Giannangelo C, De Paoli A, Schuh AK, Heimsch KC, Anderson D, Brown TG, MacRaild CA, Wu J, Wang X, Dong Y, Vennerstrom JL, Becker K, Creek DJ. Peroxide Antimalarial Drugs Target Redox Homeostasis in Plasmodium falciparum Infected Red Blood Cells. ACS Infect Dis 2022; 8:210-226. [PMID: 34985858 PMCID: PMC8762662 DOI: 10.1021/acsinfecdis.1c00550] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
![]()
Plasmodium
falciparum causes the
most lethal form of malaria. Peroxide antimalarials based on artemisinin
underpin the frontline treatments for malaria, but artemisinin resistance
is rapidly spreading. Synthetic peroxide antimalarials, known as ozonides,
are in clinical development and offer a potential alternative. Here,
we used chemoproteomics to investigate the protein alkylation targets
of artemisinin and ozonide probes, including an analogue of the ozonide
clinical candidate, artefenomel. We greatly expanded the list of proteins
alkylated by peroxide antimalarials and identified significant enrichment
of redox-related proteins for both artemisinins and ozonides. Disrupted
redox homeostasis was confirmed by dynamic live imaging of the glutathione
redox potential using a genetically encoded redox-sensitive fluorescence-based
biosensor. Targeted liquid chromatography-mass spectrometry (LC-MS)-based
thiol metabolomics also confirmed changes in cellular thiol levels.
This work shows that peroxide antimalarials disproportionately alkylate
proteins involved in redox homeostasis and that disrupted redox processes
are involved in the mechanism of action of these important antimalarials.
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Affiliation(s)
- Ghizal Siddiqui
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Carlo Giannangelo
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Amanda De Paoli
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Anna Katharina Schuh
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - Kim C. Heimsch
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - Dovile Anderson
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Timothy G. Brown
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Christopher A. MacRaild
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Jianbo Wu
- College of Pharmacy, University of Nebraska Medical Center, 986125 Nebraska Medical Center, Omaha, Nebraska 68198-6125, United States
| | - Xiaofang Wang
- College of Pharmacy, University of Nebraska Medical Center, 986125 Nebraska Medical Center, Omaha, Nebraska 68198-6125, United States
| | - Yuxiang Dong
- College of Pharmacy, University of Nebraska Medical Center, 986125 Nebraska Medical Center, Omaha, Nebraska 68198-6125, United States
| | - Jonathan L. Vennerstrom
- College of Pharmacy, University of Nebraska Medical Center, 986125 Nebraska Medical Center, Omaha, Nebraska 68198-6125, United States
| | - Katja Becker
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - Darren J. Creek
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
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14
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The Artemiside-Artemisox-Artemisone-M1 Tetrad: Efficacies against Blood Stage P. falciparum Parasites, DMPK Properties, and the Case for Artemiside. Pharmaceutics 2021; 13:pharmaceutics13122066. [PMID: 34959347 PMCID: PMC8704606 DOI: 10.3390/pharmaceutics13122066] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 11/23/2021] [Accepted: 11/24/2021] [Indexed: 01/15/2023] Open
Abstract
Because of the need to replace the current clinical artemisinins in artemisinin combination therapies, we are evaluating fitness of amino-artemisinins for this purpose. These include the thiomorpholine derivative artemiside obtained in one scalable synthetic step from dihydroartemisinin (DHA) and the derived sulfone artemisone. We have recently shown that artemiside undergoes facile metabolism via the sulfoxide artemisox into artemisone and thence into the unsaturated metabolite M1; DHA is not a metabolite. Artemisox and M1 are now found to be approximately equipotent with artemiside and artemisone in vitro against asexual P. falciparum (Pf) blood stage parasites (IC50 1.5–2.6 nM). Against Pf NF54 blood stage gametocytes, artemisox is potently active (IC50 18.9 nM early-stage, 2.7 nM late-stage), although against the late-stage gametocytes, activity is expressed, like other amino-artemisinins, at a prolonged incubation time of 72 h. Comparative drug metabolism and pharmacokinetic (DMPK) properties were assessed via po and iv administration of artemiside, artemisox, and artemisone in a murine model. Following oral administration, the composite Cmax value of artemiside plus its metabolites artemisox and artemisone formed in vivo is some 2.6-fold higher than that attained following administration of artemisone alone. Given that efficacy of short half-life rapidly-acting antimalarial drugs such as the artemisinins is associated with Cmax, it is apparent that artemiside will be more active than artemisone in vivo, due to additive effects of the metabolites. As is evident from earlier data, artemiside indeed possesses appreciably greater efficacy in vivo against murine malaria. Overall, the higher exposure levels of active drug following administration of artemiside coupled with its synthetic accessibility indicate it is much the preferred drug for incorporation into rational new artemisinin combination therapies.
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15
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Tanner L, Mashabela GT, Omollo CC, de Wet TJ, Parkinson CJ, Warner DF, Haynes RK, Wiesner L. Intracellular Accumulation of Novel and Clinically Used TB Drugs Potentiates Intracellular Synergy. Microbiol Spectr 2021; 9:e0043421. [PMID: 34585951 PMCID: PMC8557888 DOI: 10.1128/spectrum.00434-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 08/19/2021] [Indexed: 12/13/2022] Open
Abstract
The therapeutic repertoire for tuberculosis (TB) remains limited despite the existence of many TB drugs that are highly active in in vitro models and possess clinical utility. Underlying the lack of efficacy in vivo is the inability of TB drugs to penetrate microenvironments inhabited by the causative agent, Mycobacterium tuberculosis, including host alveolar macrophages. Here, we determined the ability of the phenoxazine PhX1 previously shown to be active against M. tuberculosis in vitro to differentially penetrate murine compartments, including plasma, epithelial lining fluid, and isolated epithelial lining fluid cells. We also investigated the extent of permeation into uninfected and M. tuberculosis-infected human macrophage-like Tamm-Horsfall protein 1 (THP-1) cells directly and by comparing to results obtained in vitro in synergy assays. Our data indicate that PhX1 (4,750 ± 127.2 ng/ml) penetrates more effectively into THP-1 cells than do the clinically used anti-TB agents, rifampin (3,050 ± 62.9 ng/ml), moxifloxacin (3,374 ± 48.7 ng/ml), bedaquiline (4,410 ± 190.9 ng/ml), and linezolid (770 ± 14.1 ng/ml). Compound efficacy in infected cells correlated with intracellular accumulation, reinforcing the perceived importance of intracellular penetration as a key drug property. Moreover, we detected synergies deriving from redox-stimulatory combinations of PhX1 or clofazimine with the novel prenylated amino-artemisinin WHN296. Finally, we used compound synergies to elucidate the relationship between compound intracellular accumulation and efficacy, with PhX1/WHN296 synergy levels shown to predict drug efficacy. Collectively, our data support the utility of the applied assays in identifying in vitro active compounds with the potential for clinical development. IMPORTANCE This study addresses the development of novel therapeutic compounds for the eventual treatment of drug-resistant tuberculosis. Tuberculosis continues to progress, with cases of Mycobacterium tuberculosis (M. tuberculosis) resistance to first-line medications increasing. We assess new combinations of drugs with both oxidant and redox properties coupled with a third partner drug, with the focus here being on the potentiation of M. tuberculosis-active combinations of compounds in the intracellular macrophage environment. Thus, we determined the ability of the phenoxazine PhX1, previously shown to be active against M. tuberculosis in vitro, to differentially penetrate murine compartments, including plasma, epithelial lining fluid, and isolated epithelial lining fluid cells. In addition, the extent of permeation into human macrophage-like THP-1 cells and H37Rv-infected THP-1 cells was measured via mass spectrometry and compared to in vitro two-dimensional synergy and subsequent intracellular efficacy. Collectively, our data indicate that development of new drugs will be facilitated using the methods described herein.
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Affiliation(s)
- Lloyd Tanner
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Gabriel T. Mashabela
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Charles C. Omollo
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Timothy J. de Wet
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | | | - Digby F. Warner
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DST/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Wellcome Centre for Infectious Diseases Research in Africa, University of Cape Town, Cape Town, South Africa
| | - Richard K. Haynes
- Centre of Excellence for Pharmaceutical Sciences, Faculty of Health Sciences, North-West University, Potchefstroom, South Africa
| | - Lubbe Wiesner
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
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16
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Memvanga PB, Nkanga CI. Liposomes for malaria management: the evolution from 1980 to 2020. Malar J 2021; 20:327. [PMID: 34315484 PMCID: PMC8313885 DOI: 10.1186/s12936-021-03858-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 07/16/2021] [Indexed: 12/31/2022] Open
Abstract
Malaria is one of the most prevalent parasitic diseases and the foremost cause of morbidity in the tropical regions of the world. Strategies for the efficient management of this parasitic infection include adequate treatment with anti-malarial therapeutics and vaccination. However, the emergence and spread of resistant strains of malaria parasites to the majority of presently used anti-malarial medications, on the other hand, complicates malaria treatment. Other shortcomings of anti-malarial drugs include poor aqueous solubility, low permeability, poor bioavailability, and non-specific targeting of intracellular parasites, resulting in high dose requirements and toxic side effects. To address these limitations, liposome-based nanotechnology has been extensively explored as a new solution in malaria management. Liposome technology improves anti-malarial drug encapsulation, bioavailability, target delivery, and controlled release, resulting in increased effectiveness, reduced resistance progression, and fewer adverse effects. Furthermore, liposomes are exploited as immunological adjuvants and antigen carriers to boost the preventive effectiveness of malaria vaccine candidates. The present review discusses the findings from studies conducted over the last 40 years (1980-2020) using in vitro and in vivo settings to assess the prophylactic and curative anti-malarial potential of liposomes containing anti-malarial agents or antigens. This paper and the discussion herein provide a useful resource for further complementary investigations and may pave the way for the research and development of several available and affordable anti-malarial-based liposomes and liposomal malaria vaccines by allowing a thorough evaluation of liposomes developed to date for the management of malaria.
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Affiliation(s)
- Patrick B Memvanga
- Faculty of Pharmaceutical Sciences, Laboratory of Pharmaceutics and Phytopharmaceutical Drug Development, University of Kinshasa, B.P. 212, Kinshasa XI, Democratic Republic of the Congo.
| | - Christian I Nkanga
- Faculty of Pharmaceutical Sciences, Laboratory of Pharmaceutics and Phytopharmaceutical Drug Development, University of Kinshasa, B.P. 212, Kinshasa XI, Democratic Republic of the Congo
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17
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Watson DJ, Laing L, Gibhard L, Wong HN, Haynes RK, Wiesner L. Toward New Transmission-Blocking Combination Therapies: Pharmacokinetics of 10-Amino-Artemisinins and 11-Aza-Artemisinin and Comparison with Dihydroartemisinin and Artemether. Antimicrob Agents Chemother 2021; 65:e0099021. [PMID: 34097488 PMCID: PMC8284440 DOI: 10.1128/aac.00990-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Accepted: 05/17/2021] [Indexed: 11/20/2022] Open
Abstract
As artemisinin combination therapies (ACTs) are compromised by resistance, we are evaluating triple combination therapies (TACTs) comprising an amino-artemisinin, a redox drug, and a third drug with a different mode of action. Thus, here we briefly review efficacy data on artemisone, artemiside, other amino-artemisinins, and 11-aza-artemisinin and conduct absorption, distribution, and metabolism and excretion (ADME) profiling in vitro and pharmacokinetic (PK) profiling in vivo via intravenous (i.v.) and oral (p.o.) administration to mice. The sulfamide derivative has a notably long murine microsomal half-life (t1/2 > 150 min), low intrinsic liver clearance and total plasma clearance rates (CLint 189.4, CLtot 32.2 ml/min/kg), and high relative bioavailability (F = 59%). Kinetics are somewhat similar for 11-aza-artemisinin (t1/2 > 150 min, CLint = 576.9, CLtot = 75.0 ml/min/kg), although bioavailability is lower (F = 14%). In contrast, artemether is rapidly metabolized to dihydroartemisinin (DHA) (t1/2 = 17.4 min) and eliminated (CLint = 855.0, CLtot = 119.7 ml/min/kg) and has low oral bioavailability (F) of 2%. While artemisone displays low t1/2 of <10 min and high CLint of 302.1, it displays a low CLtot of 42.3 ml/min/kg and moderate bioavailability (F) of 32%. Its active metabolite M1 displays a much-improved t1/2 of >150 min and a reduced CLint of 37.4 ml/min/kg. Artemiside has t1/2 of 12.4 min, CLint of 673.9, and CLtot of 129.7 ml/kg/min, likely a reflection of its surprisingly rapid metabolism to artemisone, reported here for the first time. DHA is not formed from any amino-artemisinin. Overall, the efficacy and PK data strongly support the development of selected amino-artemisinins as components of new TACTs.
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Affiliation(s)
- Daniel J. Watson
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Lizahn Laing
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Liezl Gibhard
- H3D, Department of Chemistry, University of Cape Town, Cape Town, South Africa
| | - Ho Ning Wong
- Centre of Excellence for Pharmaceutical Sciences, Faculty of Health Sciences, North-West University, Potchefstroom, South Africa
| | - Richard K. Haynes
- Centre of Excellence for Pharmaceutical Sciences, Faculty of Health Sciences, North-West University, Potchefstroom, South Africa
| | - Lubbe Wiesner
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
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18
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Leshabane M, Dziwornu GA, Coertzen D, Reader J, Moyo P, van der Watt M, Chisanga K, Nsanzubuhoro C, Ferger R, Erlank E, Venter N, Koekemoer L, Chibale K, Birkholtz LM. Benzimidazole Derivatives Are Potent against Multiple Life Cycle Stages of Plasmodium falciparum Malaria Parasites. ACS Infect Dis 2021; 7:1945-1955. [PMID: 33673735 DOI: 10.1021/acsinfecdis.0c00910] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The continued emergence of resistance to front-line antimalarial treatments is of great concern. Therefore, new compounds that potentially have a novel target in various developmental stages of Plasmodium parasites are needed to treat patients and halt the spread of malaria. Here, several benzimidazole derivatives were screened for activity against the symptom-causing intraerythrocytic asexual blood stages and the transmissible gametocyte stages of P. falciparum. Submicromolar activity was obtained for 54 compounds against asexual blood stage parasites with 6 potent at IC50 < 100 nM while not displaying any marked toxicity against mammalian cells. Nanomolar potency was also observed against gametocytes with two compounds active against early stage gametocytes and two compounds active against late-stage gametocytes. The transmission-blocking potential of the latter was confirmed as they could prevent male gamete exflagellation and the lead compound reduced transmission by 72% in an in vivo mosquito feeding model. These compounds therefore have activity against multiple stages of Plasmodium parasites with potential for differential targets.
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Affiliation(s)
- Meta Leshabane
- Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | | | - Dina Coertzen
- Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Janette Reader
- Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Phanankosi Moyo
- Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Mariëtte van der Watt
- Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Kelly Chisanga
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | | | - Richard Ferger
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - Erica Erlank
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, and Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, 2193, South Africa
| | - Nelius Venter
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, and Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, 2193, South Africa
| | - Lizette Koekemoer
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, and Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, 2193, South Africa
| | - Kelly Chibale
- 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
- South African Medical Research Council Drug Discovery and Development Research Unit, University of Cape Town, Rondebosch 7701, South Africa
| | - Lyn-Marie Birkholtz
- Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
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Patel OPS, Beteck RM, Legoabe LJ. Exploration of artemisinin derivatives and synthetic peroxides in antimalarial drug discovery research. Eur J Med Chem 2021; 213:113193. [PMID: 33508479 DOI: 10.1016/j.ejmech.2021.113193] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 12/04/2020] [Accepted: 01/11/2021] [Indexed: 12/22/2022]
Abstract
Malaria is a life-threatening infectious disease caused by protozoal parasites belonging to the genus Plasmodium. It caused an estimated 405,000 deaths and 228 million malaria cases globally in 2018 as per the World Malaria Report released by World Health Organization (WHO) in 2019. Artemisinin (ART), a "Nobel medicine" and its derivatives have proven potential application in antimalarial drug discovery programs. In this review, antimalarial activity of the most active artemisinin derivatives modified at C-10/C-11/C-16/C-6 positions and synthetic peroxides (endoperoxides, 1,2,4-trioxolanes, 1,2,4-trioxanes, and 1,2,4,5-tetraoxanes) are systematically summarized. The developmental trend of ART derivatives, and cyclic peroxides along with their antimalarial activity and how the activity is affected by structural variations on different sites of the compounds are discussed. This compilation would be very useful towards scaffold hopping aimed at avoiding the unnecessary complexity in cyclic peroxides, and ultimately act as a handy resource for the development of potential chemotherapeutics against Plasmodium species.
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Affiliation(s)
- Om P S Patel
- Centre of Excellence for Pharmaceutical Sciences, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa.
| | - Richard M Beteck
- Centre of Excellence for Pharmaceutical Sciences, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa
| | - Lesetja J Legoabe
- Centre of Excellence for Pharmaceutical Sciences, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa.
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Madhav H, Hoda N. An insight into the recent development of the clinical candidates for the treatment of malaria and their target proteins. Eur J Med Chem 2020; 210:112955. [PMID: 33131885 DOI: 10.1016/j.ejmech.2020.112955] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 10/08/2020] [Accepted: 10/19/2020] [Indexed: 01/18/2023]
Abstract
Malaria is an endemic disease, prevalent in tropical and subtropical regions which cost half of million deaths annually. The eradication of malaria is one of the global health priority nevertheless, current therapeutic efforts seem to be insufficient due to the emergence of drug resistance towards most of the available drugs, even first-line treatment ACT, unavailability of the vaccine, and lack of drugs with a new mechanism of action. Intensification of antimalarial research in recent years has resulted into the development of single dose multistage therapeutic agents which has advantage of overcoming the antimalarial drug resistance. The present review explored the current progress in the development of new promising antimalarials against prominent target proteins that have the potential to be a clinical candidate. Here, we also reviewed different aspects of drug resistance and highlighted new drug candidates that are currently in a clinical trial or clinical development, along with a few other molecules with excellent antimalarial activity overs ACTs. The summarized scientific value of previous approaches and structural features of antimalarials related to the activity are highlighted that will be helpful for the development of next-generation antimalarials.
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Affiliation(s)
- Hari Madhav
- Drug Design and Synthesis Laboratory, Department of Chemistry, Jamia Millia Islamia (A Central University), New Delhi, 110025, India.
| | - Nasimul Hoda
- Drug Design and Synthesis Laboratory, Department of Chemistry, Jamia Millia Islamia (A Central University), New Delhi, 110025, India.
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21
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Krzyżek P, Paluch E, Gościniak G. Synergistic Therapies as a Promising Option for the Treatment of Antibiotic-Resistant Helicobacter pylori. Antibiotics (Basel) 2020; 9:antibiotics9100658. [PMID: 33007899 PMCID: PMC7599531 DOI: 10.3390/antibiotics9100658] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 09/24/2020] [Accepted: 09/29/2020] [Indexed: 12/17/2022] Open
Abstract
Helicobacter pylori is a Gram-negative bacterium responsible for the development of gastric diseases. The issue of spreading antibiotic resistance of H. pylori and its limited therapeutic options is an important topic in modern gastroenterology. This phenomenon is greatly associated with a very narrow range of antibiotics used in standard therapies and, as a consequence, an alarmingly high detection of multidrug-resistant H. pylori strains. For this reason, scientists are increasingly focused on the search for new substances that will not only exhibit antibacterial effect against H. pylori, but also potentiate the activity of antibiotics. The aim of the current review is to present scientific reports showing newly discovered or repurposed compounds with an ability to enhance the antimicrobial activity of classically used antibiotics against H. pylori. To gain a broader context in their future application in therapies of H. pylori infections, their antimicrobial properties, such as minimal inhibitory concentrations and minimal bactericidal concentrations, dose- and time-dependent mode of action, and, if characterized, anti-biofilm and/or in vivo activity are further described. The authors of this review hope that this article will encourage the scientific community to expand research on the important issue of synergistic therapies in the context of combating H. pylori infections.
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Adebayo JO, Tijjani H, Adegunloye AP, Ishola AA, Balogun EA, Malomo SO. Enhancing the antimalarial activity of artesunate. Parasitol Res 2020; 119:2749-2764. [PMID: 32638101 PMCID: PMC7340003 DOI: 10.1007/s00436-020-06786-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 06/25/2020] [Indexed: 12/05/2022]
Abstract
The global challenge to the treatment of malaria is mainly the occurrence of resistance of malaria parasites to conventionally used antimalarials. Artesunate, a semisynthetic artemisinin compound, and other artemisinin derivatives are currently used in combination with selected active antimalarial drugs in order to prevent or delay the emergence of resistance to artemisinin derivatives. Several methods, such as preparation of hybrid compounds, combination therapy, chemical modification and the use of synthetic materials to enhance solubility and delivery of artesunate, have been employed over the years to improve the antimalarial activity of artesunate. Each of these methods has advantages it bestows on the efficacy of artesunate. This review discussed the various methods employed in enhancing the antimalarial activity of artesunate and delaying the emergence of resistance of parasite to it.
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Affiliation(s)
- J O Adebayo
- Department of Biochemistry, Faculty of Life Sciences, University of Ilorin, Ilorin, Nigeria.
| | - H Tijjani
- Department of Biochemistry, Bauchi State University, Gadau, Bauchi State, Nigeria
| | - A P Adegunloye
- Department of Biochemistry, Faculty of Life Sciences, University of Ilorin, Ilorin, Nigeria
| | - A A Ishola
- Department of Biochemistry, Faculty of Life Sciences, University of Ilorin, Ilorin, Nigeria
| | - E A Balogun
- Department of Biochemistry, Faculty of Life Sciences, University of Ilorin, Ilorin, Nigeria
| | - S O Malomo
- Department of Biochemistry, Faculty of Life Sciences, University of Ilorin, Ilorin, Nigeria
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23
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Moyo P, Shamburger W, van der Watt ME, Reader J, de Sousa ACC, Egan TJ, Maharaj VJ, Bringmann G, Birkholtz LM. Naphthylisoquinoline alkaloids, validated as hit multistage antiplasmodial natural products. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2020; 13:51-58. [PMID: 32505117 PMCID: PMC7270141 DOI: 10.1016/j.ijpddr.2020.05.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 05/13/2020] [Accepted: 05/18/2020] [Indexed: 12/20/2022]
Abstract
The discovery and development of multistage antimalarial drugs targeting intra-erythrocytic asexual and sexual Plasmodium falciparum parasites is of utmost importance to achieve the ambitious goal of malaria elimination. Here, we report the validation of naphthylisoquinoline (NIQ) alkaloids and their synthetic analogues as multistage active antimalarial drug candidates. A total of 30 compounds were tested, of which 17 exhibited IC50 values <1 μM against drug-sensitive P. falciparum parasites (NF54 strain); 15 of these retained activity against a panel of drug-resistant strains. These compounds showed low in vitro cytotoxicity against HepG2 cells, with selectivity indices of >10. The tested compounds showed activity in vitro against both early- and late-stage P. falciparum gametocytes while blocking male gamete formation (>70% inhibition of exflagellation at 2 μM). Additionally, five selected compounds were found to have good solubility (≥170 μM in PBS at pH 6.5), while metabolic stability towards human, mouse, and rat microsomes ranged from >90% to >7% after 30 min. Dioncophylline C (2a) emerged as a front runner from the study, displaying activity against both asexual parasites and gametocytes, a lack of cross-resistance to chloroquine, good solubility, and microsomal stability. Overall, this is the first report on the multistage activity of NIQs and their synthetic analogues including gametocytocidal and gametocidal effects induced by this class of compounds. Naphthylisoquinolines (NIQs) validated as antimalarial hit candidates. First report on transmission-blocking properties of NIQs and analogues. 15 compounds active across 9 P. falciparum strains, with acceptable RI <10 and SI >10. 5 compounds show good solubility and microsomal stability. Dioncophylline C is the frontrunner antimalarial candidate with multistage activity.
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Affiliation(s)
- Phanankosi Moyo
- Malaria Parasite Molecular Laboratory, Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, Faculty of Natural and Agricultural Sciences, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa
| | - William Shamburger
- Institute of Organic Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Mariëtte E van der Watt
- Malaria Parasite Molecular Laboratory, Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, Faculty of Natural and Agricultural Sciences, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa
| | - Janette Reader
- Malaria Parasite Molecular Laboratory, Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, Faculty of Natural and Agricultural Sciences, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa
| | - Ana Carolina C de Sousa
- Department of Chemistry, Faculty of Science, University of Cape Town, Rondebosch, 7701, South Africa
| | - Timothy J Egan
- Department of Chemistry, Faculty of Science, University of Cape Town, Rondebosch, 7701, South Africa; Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, 7925, South Africa
| | - Vinesh J Maharaj
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa
| | - Gerhard Bringmann
- Institute of Organic Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany; Department of Chemistry, Faculty of Natural and Agricultural Sciences, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa.
| | - Lyn-Marie Birkholtz
- Malaria Parasite Molecular Laboratory, Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, Faculty of Natural and Agricultural Sciences, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa.
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24
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Wong HN, Padín-Irizarry V, van der Watt ME, Reader J, Liebenberg W, Wiesner L, Smith P, Eribez K, Winzeler EA, Kyle DE, Birkholtz LM, Coertzen D, Haynes RK. Optimal 10-Aminoartemisinins With Potent Transmission-Blocking Capabilities for New Artemisinin Combination Therapies-Activities Against Blood Stage P. falciparum Including PfKI3 C580Y Mutants and Liver Stage P. berghei Parasites. Front Chem 2020; 7:901. [PMID: 31998692 PMCID: PMC6967409 DOI: 10.3389/fchem.2019.00901] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 12/13/2019] [Indexed: 12/31/2022] Open
Abstract
We have demonstrated previously that amino-artemisinins including artemiside and artemisone in which an amino group replaces the oxygen-bearing substituents attached to C-10 of the current clinical artemisinin derivatives dihydroartemisinin (DHA), artemether and artesunate, display potent activities in vitro against the asexual blood stages of Plasmodium falciparum (Pf). In particular, the compounds are active against late blood stage Pf gametocytes, and are strongly synergistic in combination with the redox active drug methylene blue. In order to fortify the eventual selection of optimum amino-artemisinins for development into new triple combination therapies also active against artemisinin-resistant Pf mutants, we have prepared new amino-artemisinins based on the easily accessible and inexpensive DHA-piperazine. The latter was converted into alkyl- and aryl sulfonamides, ureas and amides. These derivatives were screened together with the comparator drugs DHA and the hitherto most active amino-artemisinins artemiside and artemisone against asexual and sexual blood stages of Pf and liver stage P. berghei (Pb) sporozoites. Several of the new amino-artemisinins bearing aryl-urea and -amide groups are potently active against both asexual, and late blood stage gametocytes (IC50 0.4-1.0 nM). Although the activities are superior to those of artemiside (IC50 1.5 nM) and artemisone (IC50 42.4 nM), the latter are more active against the liver stage Pb sporozoites (IC50 artemisone 28 nM). In addition, early results indicate these compounds tend not to display reduced susceptibility against parasites bearing the Pf Kelch 13 propeller domain C580Y mutation characteristic of artemisinin-resistant Pf. Thus, the advent of the amino-artemisinins including artemiside and artemisone will enable the development of new combination therapies that by virtue of the amino-artemisinin component itself will possess intrinsic transmission-blocking capabilities and may be effective against artemisinin resistant falciparum malaria.
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Affiliation(s)
- Ho Ning Wong
- Centre of Excellence for Pharmaceutical Sciences, Faculty of Health Sciences, North-West University, Potchefstroom, South Africa
| | - Vivian Padín-Irizarry
- Center for Tropical & Emerging Global Diseases, Coverdell Center, University of Georgia, Athens, GA, United States
| | - Mariëtte E van der Watt
- Malaria Parasite Molecular Laboratory, Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | - Janette Reader
- Malaria Parasite Molecular Laboratory, Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | - Wilna Liebenberg
- Centre of Excellence for Pharmaceutical Sciences, Faculty of Health Sciences, North-West University, Potchefstroom, South Africa
| | - Lubbe Wiesner
- Division of Clinical Pharmacology, Department of Medicine, Groote Schuur Hospital, University of Cape Town, Cape Town, South Africa
| | - Peter Smith
- Division of Clinical Pharmacology, Department of Medicine, Groote Schuur Hospital, University of Cape Town, Cape Town, South Africa
| | - Korina Eribez
- School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Elizabeth A Winzeler
- School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Dennis E Kyle
- Center for Tropical & Emerging Global Diseases, Coverdell Center, University of Georgia, Athens, GA, United States
| | - Lyn-Marie Birkholtz
- Malaria Parasite Molecular Laboratory, Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | - Dina Coertzen
- Malaria Parasite Molecular Laboratory, Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | - Richard K Haynes
- Centre of Excellence for Pharmaceutical Sciences, Faculty of Health Sciences, North-West University, Potchefstroom, South Africa
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Abstract
The scientific community worldwide has realized that malaria elimination will not be possible without development of safe and effective transmission-blocking interventions. Primaquine, the only WHO recommended transmission-blocking drug, is not extensively utilized because of the toxicity issues in G6PD deficient individuals. Therefore, there is an urgent need to develop novel therapeutic interventions that can target malaria parasites and effectively block transmission. But at first, it is imperative to unravel the existing portfolio of transmission-blocking drugs. This review highlights transmission-blocking potential of current antimalarial drugs and drugs that are in various stages of clinical development. The collective analysis of the relationships between the structure and the activity of transmission-blocking drugs is expected to help in the design of new transmission-blocking antimalarials.
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26
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Stokes BH, Yoo E, Murithi JM, Luth MR, Afanasyev P, da Fonseca PCA, Winzeler EA, Ng CL, Bogyo M, Fidock DA. Covalent Plasmodium falciparum-selective proteasome inhibitors exhibit a low propensity for generating resistance in vitro and synergize with multiple antimalarial agents. PLoS Pathog 2019; 15:e1007722. [PMID: 31170268 PMCID: PMC6553790 DOI: 10.1371/journal.ppat.1007722] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 03/21/2019] [Indexed: 01/12/2023] Open
Abstract
Therapeutics with novel modes of action and a low risk of generating resistance are urgently needed to combat drug-resistant Plasmodium falciparum malaria. Here, we report that the peptide vinyl sulfones WLL-vs (WLL) and WLW-vs (WLW), highly selective covalent inhibitors of the P. falciparum proteasome, potently eliminate genetically diverse parasites, including K13-mutant, artemisinin-resistant lines, and are particularly active against ring-stage parasites. Selection studies reveal that parasites do not readily acquire resistance to WLL or WLW and that mutations in the β2, β5 or β6 subunits of the 20S proteasome core particle or in components of the 19S proteasome regulatory particle yield only <five-fold decreases in parasite susceptibility. This result compares favorably against previously published non-covalent inhibitors of the Plasmodium proteasome that can select for resistant parasites with >hundred-fold decreases in susceptibility. We observed no cross-resistance between WLL and WLW. Moreover, most mutations that conferred a modest loss of parasite susceptibility to one inhibitor significantly increased sensitivity to the other. These inhibitors potently synergized multiple chemically diverse classes of antimalarial agents, implicating a shared disruption of proteostasis in their modes of action. These results underscore the potential of targeting the Plasmodium proteasome with covalent small molecule inhibitors as a means of combating multidrug-resistant malaria. The spread of artemisinin-resistant Plasmodium falciparum malaria across Southeast Asia creates an imperative to develop new treatment options with compounds that are not susceptible to existing mechanisms of antimalarial drug resistance. Recent work has identified the P. falciparum proteasome as a promising drug target. Here, we report potent antimalarial activity of highly selective vinyl sulfone-conjugated peptide proteasome inhibitors, including against artemisinin-resistant P. falciparum early ring-stage parasites that are traditionally difficult to treat. Unlike many advanced antimalarial candidates, these covalent proteasome inhibitors do not readily select for resistance. Selection studies with cultured parasites reveal infrequent and minor decreases in susceptibility resulting from point mutations in components of the 26S proteasome, which we model using cryo-electron microscopy-based structural data. No parasites were observed to be cross-resistant to both compounds; in fact, partial resistance to one compound often created hypersensitivity to the other. We also document potent synergy between these covalent proteasome inhibitors and multiple classes of antimalarial agents, including dihydroartemisinin, the clinical candidate OZ439, and the parasite transmission-blocking agent methylene blue. Proteasome inhibitors have significant promise as components of novel combination therapies to treat multidrug-resistant malaria.
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Affiliation(s)
- Barbara H. Stokes
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, United States of America
| | - Euna Yoo
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, United States of America
| | - James M. Murithi
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, United States of America
| | - Madeline R. Luth
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California San Diego, School of Medicine, San Diego, CA, United States of America
| | - Pavel Afanasyev
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Paula C. A. da Fonseca
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Elizabeth A. Winzeler
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California San Diego, School of Medicine, San Diego, CA, United States of America
| | - Caroline L. Ng
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, United States of America
- * E-mail: (CLN); (MB); (DAF)
| | - Matthew Bogyo
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, United States of America
- * E-mail: (CLN); (MB); (DAF)
| | - David A. Fidock
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, United States of America
- Division of Infectious Diseases, Department of Medicine, Columbia University Irving Medical Center, New York, NY, United States of America
- * E-mail: (CLN); (MB); (DAF)
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27
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Moyo P, Kunyane P, Selepe MA, Eloff JN, Niemand J, Louw AI, Maharaj VJ, Birkholtz LM. Bioassay-guided isolation and identification of gametocytocidal compounds from Artemisia afra (Asteraceae). Malar J 2019; 18:65. [PMID: 30849984 PMCID: PMC6408838 DOI: 10.1186/s12936-019-2694-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 03/01/2019] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Optimal adoption of the malaria transmission-blocking strategy is currently limited by lack of safe and efficacious drugs. This has sparked the exploration of different sources of drugs in search of transmission-blocking agents. While plant species have been extensively investigated in search of malaria chemotherapeutic agents, comparatively less effort has been channelled towards exploring them in search of transmission-blocking drugs. Artemisia afra (Asteraceae), a prominent feature of South African folk medicine, is used for the treatment of a number of diseases, including malaria. In search of transmission-blocking compounds aimed against Plasmodium parasites, the current study endeavoured to isolate and identify gametocytocidal compounds from A. afra. METHODS A bioassay-guided isolation approach was adopted wherein a combination of solvent-solvent partitioning and gravity column chromatography was used. Collected fractions were continuously screened in vitro for their ability to inhibit the viability of primarily late-stage gametocytes of Plasmodium falciparum (NF54 strain), using a parasite lactate dehydrogenase assay. Chemical structures of isolated compounds were elucidated using UPLC-MS/MS and NMR data analysis. RESULTS Two guaianolide sesquiterpene lactones, 1α,4α-dihydroxybishopsolicepolide and yomogiartemin, were isolated and shown to be active (IC50 < 10 μg/ml; ~ 10 μM) against both gametocytes and intra-erythrocytic asexual P. falciparum parasites. Interestingly, 1α,4α-dihydroxybishopsolicepolide was significantly more potent against late-stage gametocytes than to early-stage gametocytes and intra-erythrocytic asexual P. falciparum parasites. Additionally, both isolated compounds were not overly cytotoxic against HepG2 cells in vitro. CONCLUSION This study provides the first instance of isolated compounds from A. afra against P. falciparum gametocytes as a starting point for further investigations on more plant species in search of transmission-blocking compounds.
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Affiliation(s)
- Phanankosi Moyo
- Malaria Parasite Molecular Laboratory, Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa
| | - Phaladi Kunyane
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa
| | - Mamoalosi A Selepe
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa
| | - Jacobus N Eloff
- Phytomedicine Programme, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag x04, Onderstepoort, Pretoria, 0110, South Africa
| | - Jandeli Niemand
- Malaria Parasite Molecular Laboratory, Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa
| | - Abraham I Louw
- Malaria Parasite Molecular Laboratory, Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa
| | - Vinesh J Maharaj
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa
| | - Lyn-Marie Birkholtz
- Malaria Parasite Molecular Laboratory, Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa.
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van Zyl L, Viljoen JM, Haynes RK, Aucamp M, Ngwane AH, du Plessis J. Topical Delivery of Artemisone, Clofazimine and Decoquinate Encapsulated in Vesicles and Their In vitro Efficacy Against Mycobacterium tuberculosis. AAPS PharmSciTech 2019; 20:33. [PMID: 30604176 DOI: 10.1208/s12249-018-1251-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 11/18/2018] [Indexed: 12/21/2022] Open
Abstract
Vesicles are widely investigated as carrier systems for active pharmaceutical ingredients (APIs). For topical delivery, they are especially effective since they create a "depot-effect" thereby concentrating the APIs in the skin. Artemisone, clofazimine and decoquinate were selected as a combination therapy for the topical treatment of cutaneous tuberculosis. Delivering APIs into the skin presents various challenges. However, utilising niosomes, liposomes and transferosomes as carrier systems may circumvent these challenges. Vesicles containing 1% of each of the three selected APIs were prepared using the thin-film hydration method. Isothermal calorimetry, differential scanning calorimetry and hot-stage microscopy indicated no to minimal incompatibility between the APIs and the vesicle components. Encapsulation efficiency was higher than 85% for all vesicle dispersions. Vesicle stability decreased and size increased with an increase in API concentration; and ultimately, niosomes were found the least stable of the different vesicle types. Skin diffusion studies were subsequently conducted for 12 h on black human female skin utilising vertical Franz diffusion cells. Transferosomes and niosomes delivered the highest average concentrations of clofazimine and decoquinate into the skin, whereas artemisone was not detected and no APIs were present in the receptor phase. Finally, efficacy against tuberculosis was tested against the Mycobacterium tuberculosis H37Rv laboratory strain. All the dispersions depicted some activity, surprisingly even the blank vesicles portrayed activity. However, the highest percentage inhibition (52%) against TB was obtained with niosomes containing 1% clofazimine.
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29
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Beteck RM, Seldon R, Coertzen D, van der Watt ME, Reader J, Mackenzie JS, Lamprecht DA, Abraham M, Eribez K, Müller J, Rui F, Zhu G, de Grano RV, Williams ID, Smit FJ, Steyn AJC, Winzeler EA, Hemphill A, Birkholtz LM, Warner DF, N’Da DD, Haynes RK. Accessible and distinct decoquinate derivatives active against Mycobacterium tuberculosis and apicomplexan parasites. Commun Chem 2018. [DOI: 10.1038/s42004-018-0062-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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