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Rathi K, Shukla M, Hassam M, Shrivastava R, Rawat V, Prakash Verma V. Recent advances in the synthesis and antimalarial activity of 1,2,4-trioxanes. Bioorg Chem 2024; 143:107043. [PMID: 38134523 DOI: 10.1016/j.bioorg.2023.107043] [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: 09/20/2023] [Revised: 11/29/2023] [Accepted: 12/15/2023] [Indexed: 12/24/2023]
Abstract
The increasing resistance of various malarial parasite strains to drugs has made the production of a new, rapid-acting, and efficient antimalarial drug more necessary, as the demand for such drugs is growing rapidly. As a major global health concern, various methods have been implemented to address the problem of drug resistance, including the hybrid drug concept, combination therapy, the development of analogues of existing medicines, and the use of drug resistance reversal agents. Artemisinin and its derivatives are currently used against multidrug- resistant P. falciparum species. However, due to its natural origin, its use has been limited by its scarcity in natural resources. As a result, finding a substitute becomes more crucial, and the peroxide group in artemisinin, responsible for the drugs biological action in the form of 1,2,4-trioxane, may hold the key to resolving this issue. The literature suggests that 1,2,4-trioxanes have the potential to become an alternative to current malaria drugs, as highlighted in this review. This is why 1,2,4-trioxanes and their derivatives have been synthesized on a large scale worldwide, as they have shown promising antimalarial activity in vivo and in vitro against Plasmodium species. Consequently, the search for a more convenient, environment friendly, sustainable, efficient, and effective synthetic pathway for the synthesis of 1,2,4-trioxanes continues. The aim of this work is to provide a comprehensive analysis of the synthesis and mechanism of action of 1,2,4-trioxanes. This systematic review highlights the most recent summaries of derivatives of 1,2,4-trioxane compounds and dimers with potential antimalarial activity from January 1988 to 2023.
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Affiliation(s)
- Komal Rathi
- Department of Chemistry, Banasthali University, Banasthali Newai 304022, Rajasthan, India
| | - Monika Shukla
- Department of Chemistry, Banasthali University, Banasthali Newai 304022, Rajasthan, India
| | | | - Rahul Shrivastava
- Department of Chemistry, Manipal University Jaipur, Jaipur (Rajasthan), VPO- Dehmi-Kalan, Off Jaipur-Ajmer Express Way, Jaipur, Rajasthan 30300, India
| | - Varun Rawat
- School of Chemistry, Tel Aviv University, Tel Aviv 6997801, Israel.
| | - Ved Prakash Verma
- Department of Chemistry, Banasthali University, Banasthali Newai 304022, Rajasthan, India.
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Kaur N, Korkor C, Mobin SM, Chibale K, Singh K. Fluorene-Chloroquine Hybrids: Synthesis, in vitro Antiplasmodial Activity, and Inhibition of Heme Detoxification Machinery of Plasmodium falciparum. ChemMedChem 2022; 17:e202200414. [PMID: 36017666 DOI: 10.1002/cmdc.202200414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 08/22/2022] [Indexed: 11/10/2022]
Abstract
Fluorene-chloroquine hybrids have been identified as a new promising class of antiplasmodial agents. The most active compound 9d exhibited good in vitro antiplasmodial activity against a chloroquine-sensitive NF54 strain of the human malaria parasite Plasmodium falciparum with an IC50 value of 139 nM. UV-visible absorption, FTIR spectral and 1H NMR titration data corroborated the binding of 9d to monomeric and µ-oxodimeric heme as well as inhibition of β-hematin formation, which collectively supported the inhibition of heme detoxification machinery in P. falciparum. In silico docking studies revealed the binding interactions of the hybrids in the active site of the wild type as well as quadruple mutant of Pf-DHFR-TS dihydrofolate enzyme. Further, the ADMET parameters were predicted and were in good agreement with the expected values, suggesting the drug likeness of the synthesized hybrid molecules.Introduction.
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Affiliation(s)
- Navpreet Kaur
- IIT Indore Discipline of Chemistry: Indian Institute of Technology Indore Discipline of Chemistry, Chemistry, INDIA
| | - Constance Korkor
- University of Cape Town Institute of Infectious Disease and Molecular Medicine, Chemistry, INDIA
| | - Shaikh M Mobin
- IIT Indore: Indian Institute of Technology Indore, Chemistry, INDIA
| | - Kelly Chibale
- University of Cape Town Institute of Infectious Disease and Molecular Medicine, Chemistry, INDIA
| | - Kamaljit Singh
- Guru Nanak Dev University, Department of Chemistry, Centre for Advanced Studies-II, Guru Nanak Dev University, Amritsar-143005, 143005, Amritsar, INDIA
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Gujjari L, Kalani H, Pindiprolu SK, Arakareddy BP, Yadagiri G. Current challenges and nanotechnology-based pharmaceutical strategies for the treatment and control of malaria. Parasite Epidemiol Control 2022; 17:e00244. [PMID: 35243049 PMCID: PMC8866151 DOI: 10.1016/j.parepi.2022.e00244] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 12/12/2021] [Accepted: 02/13/2022] [Indexed: 12/19/2022] Open
Abstract
Malaria is one of the prevalent tropical diseases caused by the parasitic protozoan of the genus Plasmodium spp. With an estimated 228 million cases, it is a major public health concern with high incidence of morbidity and mortality worldwide. The emergence of drug-resistant parasites, inadequate vector control measures, and the non-availability of effective vaccine(s) against malaria pose a serious challenge to malaria eradication especially in underdeveloped and developing countries. Malaria treatment and control comprehensively relies on chemical compounds, which encompass various complications, including severe toxic effects, emergence of drug resistance, and high cost of therapy. To overcome the clinical failures of anti-malarial chemotherapy, a new drug development is of an immediate need. However, the drug discovery and development process is expensive and time consuming. In such a scenario, nanotechnological strategies may offer promising alternative approach for the treatment and control of malaria, with improved efficacy and safety. Nanotechnology based formulations of existing anti-malarial chemotherapeutic agents prove to exceed the limitations of existing therapies in relation to optimum therapeutic benefits, safety, and cost effectiveness, which indeed advances the patient's compliance in treatment. In this review, the shortcomings of malaria therapeutics and necessity of nanotechnological strategies for treating malaria were discussed.
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Affiliation(s)
- Lohitha Gujjari
- Centre of Infectious Diseases, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, S. A. S. Nagar, Punjab 160 062, India
- Department of Entomology, The Ohio State University, Ohio Agricultural Research and Development Center, 1680 Madison Avenue, Wooster, OH 44691, USA
| | - Hamed Kalani
- Infectious Diseases Research Center, Golestan University of Medical Sciences, Gorgan, Iran
| | - Sai Kiran Pindiprolu
- Department of Pharmacology, School of Pharmaceutical Sciences and Technologies, Jawaharlal Nehru Technological University, Kakinada, Andhra Pradesh 533003, India
| | | | - Ganesh Yadagiri
- Department of Pharmacology, School of Pharmaceutical Sciences and Technologies, Jawaharlal Nehru Technological University, Kakinada, Andhra Pradesh 533003, India
- Centre for Food Animal Health, The Ohio State University, Ohio Agricultural Research and Development Center, 1680 Madison Avenue, Wooster, OH 44691, USA
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Qureshi IA, Saini M, Are S. Pyridoxal Kinase of Disease-causing Human Parasites: Structural and
Functional Insights to Understand its Role in Drug Discovery. Curr Protein Pept Sci 2022; 23:271-289. [DOI: 10.2174/1389203723666220519155025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/14/2022] [Accepted: 04/06/2022] [Indexed: 11/22/2022]
Abstract
Abstract:
Human parasites cause several diseased conditions with high morbidity and mortality in a
large section of the population residing in various geographical areas. Nearly three billion people suffer
from either one or many parasitic infections globally, with almost one million deaths annually. In spite
of extensive research and advancement in the medical field, no effective vaccine is available against
prominent human parasitic diseases that necessitate identification of novel targets for designing specific
inhibitors. Vitamin B6 is an important ubiquitous co-enzyme that participates in several biological processes
and plays an important role in scavenging ROS (reactive oxygen species) along with providing
resistance to oxidative stress. Moreover, the absence of the de novo vitamin B6 biosynthetic pathway in
human parasites makes this pathway indispensable for the survival of these pathogens. Pyridoxal kinase
(PdxK) is a crucial enzyme for vitamin B6 salvage pathway and participates in the process of vitamers
B6 phosphorylation. Since the parasites are dependent on pyridoxal kinase for their survival and infectivity
to the respective hosts, it is considered a promising candidate for drug discovery. The detailed
structural analysis of PdxK from disease-causing parasites has provided insights into the catalytic
mechanism of this enzyme as well as significant differences from their human counterpart. Simultaneously,
structure-based studies have identified small lead molecules that can be exploited for drug discovery
against protozoan parasites. The present review provides structural and functional highlights of
pyridoxal kinase for its implication in developing novel and potent therapeutics to combat fatal parasitic
diseases.
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Affiliation(s)
- Insaf Ahmed Qureshi
- Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, Prof. C.R. Rao
Road, Hyderabad 500046, India
| | - Mayank Saini
- Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, Prof. C.R. Rao
Road, Hyderabad 500046, India
| | - Sayanna Are
- Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, Prof. C.R. Rao
Road, Hyderabad 500046, India
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Thakkar M, S B. Combating malaria with nanotechnology-based targeted and combinatorial drug delivery strategies. Drug Deliv Transl Res 2017; 6:414-25. [PMID: 27067712 DOI: 10.1007/s13346-016-0290-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Despite the advancement of science, infectious diseases such as malaria remain an ongoing challenge globally. The main reason this disease still remains a menace in many countries around the world is the development of resistance to many of the currently available anti-malarial drugs. While developing new drugs is rather expensive and the prospect of a potent vaccine is still evading our dream of a malaria-free world, one of the feasible options is to package the older drugs in newer ways. For this, nano-sized drug delivery vehicles have been used and are proving to be promising prospects in the way malaria will be treated in the future. Since, monotherapy has given way to combination therapy in malaria treatment, nanotechnology-based delivery carriers enable to encapsulate various drug moieties in the same package, thus avoiding the complications involved in conjugation chemistry to produce hybrid drug molecules. Further, we envisage that using targeted delivery approaches, we may be able to achieve a much better radical cure and curb the side effects associated with the existing drug molecules. Thus, this review will focus on some of the nanotechnology-based combination and targeted therapies and will discuss the possibilities of better therapies that may be developed in the future.
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Affiliation(s)
- Miloni Thakkar
- Department of Biological Sciences, Sunandan Divatia School of Science, NMIMS (Deemed-to-be) University, Vile Parle (W), Mumbai, 400056, India
| | - Brijesh S
- Department of Biological Sciences, Sunandan Divatia School of Science, NMIMS (Deemed-to-be) University, Vile Parle (W), Mumbai, 400056, India.
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Baruah UK, Gowthamarajan K, Vanka R, Karri VVSR, Selvaraj K, Jojo GM. Malaria treatment using novel nano-based drug delivery systems. J Drug Target 2017; 25:567-581. [PMID: 28166440 DOI: 10.1080/1061186x.2017.1291645] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We reside in an era of technological innovation and advancement despite which infectious diseases like malaria remain to be one of the greatest threats to the humans. Mortality rate caused by malaria disease is a huge concern in the twenty-first century. Multiple drug resistance and nonspecific drug targeting of the most widely used drugs are the main reasons/drawbacks behind the failure in malarial therapy. Dose-related toxicity because of high doses is also a major concern. Therefore, to overcome these problems nano-based drug delivery systems are being developed to facilitate site-specific or target-based drug delivery and hence minimizing the development of resistance progress and dose-dependent toxicity issues. In this review, we discuss about the shortcomings in treating malaria and how nano-based drug delivery systems can help in curtailing the infectious disease malaria.
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Affiliation(s)
- Uday Krishna Baruah
- a Department of Pharmaceutics , JSS College of Pharmacy, Ootacamund, JSS University , Mysuru , India
| | - Kuppusamy Gowthamarajan
- a Department of Pharmaceutics , JSS College of Pharmacy, Ootacamund, JSS University , Mysuru , India
| | - Ravisankar Vanka
- a Department of Pharmaceutics , JSS College of Pharmacy, Ootacamund, JSS University , Mysuru , India
| | | | - Kousalya Selvaraj
- a Department of Pharmaceutics , JSS College of Pharmacy, Ootacamund, JSS University , Mysuru , India
| | - Gifty M Jojo
- a Department of Pharmaceutics , JSS College of Pharmacy, Ootacamund, JSS University , Mysuru , India
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8
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Synthetic strategy with representation on mechanistic pathway for the therapeutic applications of dihydroquinazolinones. Eur J Med Chem 2016; 123:596-630. [DOI: 10.1016/j.ejmech.2016.08.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 08/01/2016] [Accepted: 08/01/2016] [Indexed: 01/25/2023]
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9
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Singh K, Agarwal A, Khan SI, Walker LA, Tekwani BL. Growth, Drug Susceptibility, and Gene Expression Profiling of Plasmodium falciparum Cultured in Medium Supplemented with Human Serum. ACTA ACUST UNITED AC 2016; 12:1109-14. [DOI: 10.1177/1087057107310638] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In vitro cultivation of Plasmodium falciparum has been extremely useful in understanding the biology of the human malaria parasite as well as research on the discovery of new antimalarial drugs and vaccines. A chemically defined serum-free medium supplemented with lipid-rich bovine serum albumin (AlbuMAX I) offers the following advantages over human serum-supplemented media for the in vitro culture of P. falciparum: 1) improved growth profile, with more than a 2-fold higher yield of the parasites at any stage of the growth cycle; 2) suitability for in vitro antimalarial screening, as the parasites grown in AlbuMAX and human serum-supplemented media show similar sensitivity to standard and novel antimalarials as well as natural product extracts in the in vitro drug susceptibility assays; and 3) DNA microarray analysis comparing the global gene expression profile of sorbitol-synchronized P. falciparum trophozoites grown in the 2 different media, indicating minimal differences. ( Journal of Biomolecular Screening 2007:1109-1114)
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Affiliation(s)
- Kshipra Singh
- National Center for Natural Products Research, School of Pharmacy, University of Mississippi, University, Mississippi, Gastroenterology Division, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Ameeta Agarwal
- National Center for Natural Products Research, School of Pharmacy, University of Mississippi, University, Mississippi
| | - Shabana I. Khan
- National Center for Natural Products Research, School of Pharmacy, University of Mississippi, University, Mississippi
| | - Larry A. Walker
- National Center for Natural Products Research, School of Pharmacy, University of Mississippi, University, Mississippi
| | - Babu L. Tekwani
- National Center for Natural Products Research, School of Pharmacy, University of Mississippi, University, Mississippi,
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10
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Magalhães GA, Moura Neto E, Sombra VG, Richter AR, Abreu CMWS, Feitosa JPA, Paula HCB, Goycoolea FM, de Paula RCM. Chitosan/Sterculia striata polysaccharides nanocomplex as a potential chloroquine drug release device. Int J Biol Macromol 2016; 88:244-53. [PMID: 27041650 DOI: 10.1016/j.ijbiomac.2016.03.070] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 03/29/2016] [Accepted: 03/31/2016] [Indexed: 11/29/2022]
Abstract
Nanoparticles are produced by means of polyelectrolyte complexation (PEC) of oppositely charged polycationic chitosan (CH) with polyanionic polysaccharide extracted from Sterculia striata exudates (rhamnogalacturonoglycan (RG)-type polysaccharide). The nanoparticles formed with low-molar-mass CH are larger than those formed with high-molar-mass CH. This behavior is in contrast with that previously observed for other systems and may be attributed to different mechanisms related to the association of CH with RG of higher persistence length chain than that of CH. Nanoparticles harnessed with a charge ratio (n(+)/n(-)) of <1 are smaller than particles with an excess of polycations. Particles with hydrodynamic sizes smaller than 100nm are achieved using a polyelectrolyte concentration of 10(-4)gmL(-1) and charge ratio (n(+)/n(-)) of <1. The CH/RG nanoparticles are associated with chloroquine (CQ) with an efficiency of 28% and release it for up to ∼60% within ∼10h, whereas in the latter, only ∼40% of the CQ was released after 24h. The main factor that influenced drug release rate is the nanoparticle charge ratio.
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Affiliation(s)
- Guilherme A Magalhães
- Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará, Fortaleza, Ceará, Brazil, CP 6021, CEP 60455-760
| | - Erico Moura Neto
- Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará, Fortaleza, Ceará, Brazil, CP 6021, CEP 60455-760
| | - Venícios G Sombra
- Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará, Fortaleza, Ceará, Brazil, CP 6021, CEP 60455-760
| | - Ana R Richter
- Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará, Fortaleza, Ceará, Brazil, CP 6021, CEP 60455-760
| | - Clara M W S Abreu
- Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará, Fortaleza, Ceará, Brazil, CP 6021, CEP 60455-760
| | - Judith P A Feitosa
- Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará, Fortaleza, Ceará, Brazil, CP 6021, CEP 60455-760
| | - Haroldo C B Paula
- Departamento de Química Analitica e Fisico-Química, Universidade Federal do Ceará, Fortaleza, Ceará, Brazil, CP 6021,CEP 60455-760
| | | | - Regina C M de Paula
- Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará, Fortaleza, Ceará, Brazil, CP 6021, CEP 60455-760.
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Ghandi M, Zarezadeh N. A one-pot four-component reaction providing quinoline-based 1,4-dihydropyridines. JOURNAL OF THE IRANIAN CHEMICAL SOCIETY 2015. [DOI: 10.1007/s13738-015-0596-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Kaur H, Machado M, de Kock C, Smith P, Chibale K, Prudêncio M, Singh K. Primaquine-pyrimidine hybrids: synthesis and dual-stage antiplasmodial activity. Eur J Med Chem 2015; 101:266-73. [PMID: 26142491 DOI: 10.1016/j.ejmech.2015.06.045] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Revised: 06/21/2015] [Accepted: 06/22/2015] [Indexed: 10/23/2022]
Abstract
A series of novel pyrimidine-primaquine hybrids were synthesized and their effectiveness against the blood and liver stages of malaria parasites was evaluated. The hybrids displayed enhanced liver stage in vitro activity against P. berghei liver stage infection.
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Affiliation(s)
- Hardeep Kaur
- Department of Chemistry, UGC-Centre for Advanced Studies-II, Guru Nanak Dev University, Amritsar 143005, India
| | - Marta Machado
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Carmen de Kock
- Division of Pharmacology, Department of Medicine, University of Cape Town, Observatory 7925, South Africa
| | - Peter Smith
- Division of Pharmacology, Department of Medicine, University of Cape Town, Observatory 7925, South Africa
| | - Kelly Chibale
- Department of Chemistry, South African Medical Research Council Drug Discovery and Development Research Unit, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch 701, South Africa
| | - Miguel Prudêncio
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal
| | - Kamaljit Singh
- Department of Chemistry, UGC-Centre for Advanced Studies-II, Guru Nanak Dev University, Amritsar 143005, India.
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Affiliation(s)
- Paloma F. Salas
- Medicinal Inorganic Chemistry
Group, Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia
V6T 1Z1, Canada
| | - Christoph Herrmann
- Medicinal Inorganic Chemistry
Group, Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia
V6T 1Z1, Canada
- Advanced
Applied Physics Solutions, TRIUMF, 4004
Wesbrook Mall, Vancouver, British Columbia
V6T 2A3, Canada
| | - Chris Orvig
- Medicinal Inorganic Chemistry
Group, Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia
V6T 1Z1, Canada
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Talevich E, Tobin AB, Kannan N, Doerig C. An evolutionary perspective on the kinome of malaria parasites. Philos Trans R Soc Lond B Biol Sci 2012; 367:2607-18. [PMID: 22889911 DOI: 10.1098/rstb.2012.0014] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Malaria parasites belong to an ancient lineage that diverged very early from the main branch of eukaryotes. The approximately 90-member plasmodial kinome includes a majority of eukaryotic protein kinases that clearly cluster within the AGC, CMGC, TKL, CaMK and CK1 groups found in yeast, plants and mammals, testifying to the ancient ancestry of these families. However, several hundred millions years of independent evolution, and the specific pressures brought about by first a photosynthetic and then a parasitic lifestyle, led to the emergence of unique features in the plasmodial kinome. These include taxon-restricted kinase families, and unique peculiarities of individual enzymes even when they have homologues in other eukaryotes. Here, we merge essential aspects of all three malaria-related communications that were presented at the Evolution of Protein Phosphorylation meeting, and propose an integrated discussion of the specific features of the parasite's kinome and phosphoproteome.
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Affiliation(s)
- Eric Talevich
- Department of Biochemistry and Molecular Biology and Institute of Bioinformatics, University of Georgia, 120 Green Street, Athens, GA 30602-7229, USA
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15
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Aureggi V, Ehmke V, Wieland J, Schweizer WB, Bernet B, Bur D, Meyer S, Rottmann M, Freymond C, Brun R, Breit B, Diederich F. Potent inhibitors of malarial aspartic proteases, the plasmepsins, by hydroformylation of substituted 7-azanorbornenes. Chemistry 2012; 19:155-64. [PMID: 23161835 DOI: 10.1002/chem.201202941] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Indexed: 12/23/2022]
Abstract
The increasing prevalence of multidrug-resistant strains of the malarial parasite Plasmodium falciparum requires the urgent development of new therapeutic agents with novel modes of action. The vacuolar malarial aspartic proteases plasmepsin (PM) I, II, and IV are involved in hemoglobin degradation and play a central role in the growth and maturation of the parasite in the human host. We report the structure-based design, synthesis, and in vitro evaluation of a new generation of PM inhibitors featuring a highly decorated 7-azabicyclo[2.2.1]heptane core. While this protonated central core addresses the catalytic Asp dyad, three substituents bind to the flap, the S1/S3, and the S1' pockets of the enzymes. A hydroformylation reaction is the key synthetic step for the introduction of the new vector reaching into the S1' pocket. The configuration of the racemic ligands was confirmed by extensive NMR and X-ray crystallographic analysis. In vitro biological assays revealed high potency of the new inhibitors against the three plasmepsins (IC(50) values down to 6 nM) and good selectivity towards the closely related human cathepsins D and E. The occupancy of the S1' pocket makes an essential contribution to the gain in binding affinity and selectivity, which is particularly large in the case of the PM IV enzyme. Designing non-peptidic ligands for PM II is a valid route to generate compounds that inhibit the entire family of vacuolar plasmepsins.
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Affiliation(s)
- Valentina Aureggi
- Laboratorium für Organische Chemie, ETH Zurich, Hönggerberg HCI, 8093 Zurich, Switzerland
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Efunshile M, Amoo AOJ, Akintunde GB, Ojelekan OD, König W, König B. Use and effects of malaria control measures in pregnancy in Lagos, Nigeria. THE KOREAN JOURNAL OF PARASITOLOGY 2012; 49:365-71. [PMID: 22355203 PMCID: PMC3279674 DOI: 10.3347/kjp.2011.49.4.365] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 08/10/2011] [Accepted: 08/10/2011] [Indexed: 11/23/2022]
Abstract
In Nigeria, malaria causes up to 11% of maternal mortality. Our main aim was to find out the most common mosquito control measures employed by the pregnant women in Lagos and their effects on malaria infection. The study was carried out over a period of 6 months during which trained interviewers administered questionnaires to 400 pregnant women. The prevalence of malaria was 8.4%. There was no significant association between the prevalence of malaria and age, level of education, or occupation of the participants. Pregnant women in the age range 26-30 had the mean parasite density (409.9 ± 196.80). Insecticide spray (32.8%), mosquito coil (27.5%), and insecticide-treated nets (ITN) (15.5%) were the major mosquito control measures employed by the participants while the prevalence of infection among them were 2.3%, 6.2%, and 3.2%, respectively (P<0.05). Only 18.3% of the women had taken more than one dose of intermittent preventive treatment (IPT), while another 11.8% had taken a single dose. The infection rate among them was 4.1% and 6.4%, respectively. Malaria prevalence was highest among those who had not received any dose of IPT (10%). This study showed that the use of ITN and IPT among the pregnant women were still unacceptably low. It also showed that the use of insecticide spray which was the most common malaria control measure adopted by the participants was effective despite the fact that it is not a National Malaria Control Policy. We recommend that a sustained integrated mosquito management and public education should be strengthened in Nigeria.
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Roy A, D'Annessa I, Nielsen CJF, Tordrup D, Laursen RR, Knudsen BR, Desideri A, Andersen FF. Peptide Inhibition of Topoisomerase IB from Plasmodium falciparum. Mol Biol Int 2011; 2011:854626. [PMID: 22091414 PMCID: PMC3200115 DOI: 10.4061/2011/854626] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Accepted: 03/03/2011] [Indexed: 11/21/2022] Open
Abstract
Control of diseases inflicted by protozoan parasites such as Leishmania, Trypanosoma, and Plasmodium, which pose a serious threat to human health worldwide, depends on a rather small number of antiparasite drugs, of which many are toxic and/or inefficient. Moreover, the increasing occurrence of drug-resistant parasites emphasizes the need for new and effective antiprotozoan drugs. In the current study, we describe a synthetic peptide, WRWYCRCK, with inhibitory effect on the essential enzyme topoisomerase I from the malaria-causing parasite Plasmodium falciparum. The peptide inhibits specifically the transition from noncovalent to covalent DNA binding of P. falciparum topoisomerase I, while it does not affect the ligation step of catalysis. A mechanistic explanation for this inhibition is provided by molecular docking analyses. Taken together the presented results suggest that synthetic peptides may represent a new class of potential antiprotozoan drugs.
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Affiliation(s)
- Amit Roy
- Department of Molecular Biology and Interdisciplinary Nanoscience Center (iNANO), Aarhus University, C.F. Møllers Allé 3, Building 1130, 8000 Aarhus C, Denmark
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Abruquah H, Bio F, Tay S, Lawson B. Resistance-mediating polymorphisms of Plasmodium falciparum among isolates from children with severe malaria in kumasi, ghana. Ghana Med J 2011; 44:52-8. [PMID: 21327004 DOI: 10.4314/gmj.v44i2.68884] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Antimalarial drug resistance has been a major contributor to the failure of the battle against malaria in many developing countries. The P. falciparum genes, pfcrt and pfmdr-1, have been implicated in chloroquine resistance. The objective of this study was to determine the presence of mutant alleles of these chloroquine resistance genes among isolates of P. falciparum from children presenting with severe malaria in Ghana. METHODS Venous blood samples were taken from patients, and plasma chloroquine levels measured. P. falciparum chromosomal DNA was isolated from the blood samples, and subjected to PCR, restriction digestion and sequencing. Resulting data were analysed using the STATA statistical software. RESULTS Of 140 children recruited into the study, 109 (77.9%) had detectable pre-treatment chloroquine levels. PCR and restriction digestion analysis of the pfcrt gene indicated that 124 (88.6%) had the mutant T76 gene, and that this correlated with higher chloroquine levels. Sequence analysis of these showed consistent genetic sequences for chloroquine resistant and sensitive parasites with respect to Pfcrt codons 72 through 76.The Pfcrt T76 mutation was found in 88.4% of isolates having the Pfmdr-1Y86 mutation. The Pfmdr-1 Y86 mutation was found in 67.6% of isolates having the Pfcrt T76 mutation. CONCLUSION The study affirms Pfcrt as a better chloroquine resistance marker. Both mutations are independently selected by chloroquine levels and that one mutation (Y86) might modify/increase the effect of the other (T76). This study also depicts the much-overlooked antimalarial drug resistance situation in the area and emphasizes the need for a proper treatment strategy.
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Affiliation(s)
- Hh Abruquah
- University Health Services, Kwame Nkrumah University of Science & Technology, Kumasi, Ghana
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Alba S, Hetzel MW, Nathan R, Alexander M, Lengeler C. Assessing the impact of malaria interventions on morbidity through a community-based surveillance system. Int J Epidemiol 2011; 40:405-16. [PMID: 21216742 DOI: 10.1093/ije/dyq240] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The ACCESS Programme aims at understanding and improving access to prompt and effective malaria treatment in rural Tanzania with a set of integrated interventions targeting both users and providers. The aim of this article is to evaluate the programme's impact on the community and health facility burden of malaria and to investigate the value of community-based reporting for routine malaria control programme monitoring. METHODS This work was implemented within the Ifakara Demographic Surveillance System (DSS) between 2004 and 2008. At community level the DSS staff routinely collected data on reported history of fever and severe malaria (convulsions) based on a 2-week recall. In parallel, we collected in-patient and out-patient fever and malaria diagnoses data from the 15 health facilities in the area. Treatment-seeking surveys conducted in the study area and nationally representative data were used to validate our measure of community fever. RESULTS Between 2005 and 2008, community-reported fever incidence rates in children under the age of 5 years declined by 34%, from 4.9 to 3.2 average cases per child per year, whereas convulsions, a marker of severe malaria morbidity in children, decreased by 46%, from 4263 to 2320 cases for every 100,000 children per year. The decrease in the community rates was paralleled by a decrease in the health facility fever rates, although the number of fever cases seen in health facilities did not change because of population growth. Our data showed very good internal and external consistency with independent local and national surveys. CONCLUSIONS There is an evidence of a substantial decline in the community burden of malaria morbidity between 2005 and 2008 in the Kilombero and Ulanga DSS areas in Tanzania, most likely as a result of malaria control efforts. The good internal and external consistency of the data shows that history of fever in the previous 2 weeks in children under the age of 5 years can be used as a morbidity monitoring tool.
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Affiliation(s)
- Sandra Alba
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.
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20
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Is halofantrine ototoxic? Experimental study on guinea pig cochlea model. The Journal of Laryngology & Otology 2010; 124:1061-6. [PMID: 20537205 DOI: 10.1017/s0022215110001301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
INTRODUCTION Halofantrine is a newly developed antimalarial drug used for the treatment of Plasmodium falciparum malaria. The introduction of this drug has been delayed because of its possible side effects, and due to insufficient studies on adverse reactions in humans. There have been no studies investigating its effect on hearing. METHODS Thirty guinea pigs were divided into three groups: a control group, a halofantrine therapeutic dose group and a halofantrine double therapeutic dose group. One cochlea specimen from each animal was stained with haematoxylin and eosin and the other with toluidine blue. RESULTS No changes were detected in the control group. The halofantrine therapeutic dose group showed loss and distortion of inner hair cells and inner phalangeal cells, and loss of spiral ganglia cells. In the halofantrine double therapeutic dose group, the inner and outer hair cells were distorted and there was loss of spiral ganglia cells. CONCLUSION Halofantrine has mild to moderate pathological effects on cochlea histology, and can be considered an ototoxic drug.
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Santos-Magalhães NS, Mosqueira VCF. Nanotechnology applied to the treatment of malaria. Adv Drug Deliv Rev 2010; 62:560-75. [PMID: 19914313 DOI: 10.1016/j.addr.2009.11.024] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/14/2009] [Indexed: 12/24/2022]
Abstract
Despite the fact that we live in an era of advanced technology and innovation, infectious diseases, like malaria, continue to be one of the greatest health challenges worldwide. The main drawbacks of conventional malaria chemotherapy are the development of multiple drug resistance and the non-specific targeting to intracellular parasites, resulting in high dose requirements and subsequent intolerable toxicity. Nanosized carriers have been receiving special attention with the aim of minimizing the side effects of drug therapy, such as poor bioavailability and the selectivity of drugs. Several nanosized delivery systems have already proved their effectiveness in animal models for the treatment and prophylaxis of malaria. A number of strategies to deliver antimalarials using nanocarriers and the mechanisms that facilitate their targeting to Plasmodium spp.-infected cells are discussed in this review. Taking into account the peculiarities of malaria parasites, the focus is placed particularly on lipid-based (e.g., liposomes, solid lipid nanoparticles and nano and microemulsions) and polymer-based nanocarriers (nanocapsules and nanospheres). This review emphasizes the main requirements for developing new nanotechnology-based carriers as a promising choice in malaria treatment, especially in the case of severe cerebral malaria.
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García-Estrada C, Prada CF, Fernández-Rubio C, Rojo-Vázquez F, Balaña-Fouce R. DNA topoisomerases in apicomplexan parasites: promising targets for drug discovery. Proc Biol Sci 2010; 277:1777-87. [PMID: 20200034 DOI: 10.1098/rspb.2009.2176] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The phylum Apicomplexa includes a large group of protozoan parasites responsible for a wide range of animal and human diseases. Destructive pathogens, such as Plasmodium falciparum and Plasmodium vivax, causative agents of human malaria, Cryptosporidium parvum, responsible of childhood diarrhoea, and Toxoplasma gondii, responsible for miscarriages and abortions in humans, are frequently associated with HIV immunosuppression in AIDS patients. The lack of effective vaccines, along with years of increasing pressure to eradicate outbreaks with the use of drugs, has favoured the formation of multi-drug resistant strains in endemic areas. Almost all apicomplexan of medical interest contain two endosymbiotic organelles that contain their own mitochondrial and apicoplast DNA. Apicoplast is an attractive target for drug testing because in addition to harbouring singular metabolic pathways absent in the host, it also has its own transcription and translation machinery of bacterial origin. Accordingly, apicomplexan protozoa contain an interesting mixture of enzymes to unwind DNA from eukaryotic and prokaryotic origins. On the one hand, the main mechanism of DNA unwinding includes the scission of one-type I-or both DNA strands-type II eukaryotic topoisomerases, establishing transient covalent bonds with the scissile end. These enzymes are targeted by camptothecin and etoposide, respectively, two natural drugs whose semisynthetic derivatives are currently used in cancer chemotherapy. On the other hand, DNA gyrase is a bacterial-borne type II DNA topoisomerase that operates within the apicoplast and is effectively targeted by bacterial antibiotics like fluoroquinolones and aminocoumarins. The present review is an update on the new findings concerning topoisomerases in apicomplexan parasites and the role of these enzymes as targets for therapeutic agents.
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Affiliation(s)
- Carlos García-Estrada
- Departamento de Ciencias Biomédicas (INTOXCAL), Universidad de León, , Campus de Vegazana s/n, León, Spain
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Antiparasitic agents. Infect Dis (Lond) 2010. [DOI: 10.1016/b978-0-323-04579-7.00150-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Dong Y, Wittlin S, Sriraghavan K, Chollet J, Charman SA, Charman WN, Scheurer C, Urwyler H, Santo Tomas J, Snyder C, Creek DJ, Morizzi J, Koltun M, Matile H, Wang X, Padmanilayam M, Tang Y, Dorn A, Brun R, Vennerstrom JL. The Structure−Activity Relationship of the Antimalarial Ozonide Arterolane (OZ277). J Med Chem 2009; 53:481-91. [DOI: 10.1021/jm901473s] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yuxiang Dong
- College of Pharmacy, University of Nebraska Medical Center, 986025 Nebraska Medical Center, Omaha, NE
| | - Sergio Wittlin
- Swiss Tropical Institute, Socinstrasse 57, CH-4002 Basel, Switzerland
| | - Kamaraj Sriraghavan
- College of Pharmacy, University of Nebraska Medical Center, 986025 Nebraska Medical Center, Omaha, NE
| | - Jacques Chollet
- Swiss Tropical Institute, Socinstrasse 57, CH-4002 Basel, Switzerland
| | - Susan A. Charman
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - William N. Charman
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052, Australia
| | | | - Heinrich Urwyler
- Basilea Pharmaceutica Ltd., Grenzacherstrasse 487, CH-4058 Basel, Switzerland
| | - Josefina Santo Tomas
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052, Australia
| | | | - Darren J. Creek
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Julia Morizzi
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Maria Koltun
- Centre for Drug Candidate Optimisation, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Hugues Matile
- F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Xiaofang Wang
- College of Pharmacy, University of Nebraska Medical Center, 986025 Nebraska Medical Center, Omaha, NE
| | - Maniyan Padmanilayam
- College of Pharmacy, University of Nebraska Medical Center, 986025 Nebraska Medical Center, Omaha, NE
| | - Yuanqing Tang
- College of Pharmacy, University of Nebraska Medical Center, 986025 Nebraska Medical Center, Omaha, NE
| | - Arnulf Dorn
- F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland
| | - Reto Brun
- Swiss Tropical Institute, Socinstrasse 57, CH-4002 Basel, Switzerland
| | - Jonathan L. Vennerstrom
- College of Pharmacy, University of Nebraska Medical Center, 986025 Nebraska Medical Center, Omaha, NE
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Doerig C, Abdi A, Bland N, Eschenlauer S, Dorin-Semblat D, Fennell C, Halbert J, Holland Z, Nivez MP, Semblat JP, Sicard A, Reininger L. Malaria: targeting parasite and host cell kinomes. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2009; 1804:604-12. [PMID: 19840874 DOI: 10.1016/j.bbapap.2009.10.009] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Revised: 10/05/2009] [Accepted: 10/07/2009] [Indexed: 10/20/2022]
Abstract
Malaria still remains one of the deadliest infectious diseases, and has a tremendous morbidity and mortality impact in the developing world. The propensity of the parasites to develop drug resistance, and the relative reluctance of the pharmaceutical industry to invest massively in the developments of drugs that would offer only limited marketing prospects, are major issues in antimalarial drug discovery. Protein kinases (PKs) have become a major family of targets for drug discovery research in a number of disease contexts, which has generated considerable resources such as kinase-directed libraries and high throughput kinase inhibition assays. The phylogenetic distance between malaria parasites and their human host translates into important divergences in their respective kinomes, and most Plasmodium kinases display atypical properties (as compared to mammalian PKs) that can be exploited towards selective inhibition. Here, we discuss the taxon-specific kinases possessed by malaria parasites, and give an overview of target PKs that have been validated by reverse genetics, either in the human malaria parasite Plasmodium falciparum or in the rodent model Plasmodium berghei. We also briefly allude to the possibility of attacking Plasmodium through the inhibition of human PKs that are required for survival of this obligatory intracellular parasite, and which are targets for other human diseases.
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Affiliation(s)
- Christian Doerig
- Inserm U609/Wellcome Centre for Molecular Parasitology, University of Glasgow, 120 University Place, Glasgow G12 8TA, Scotland, UK.
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Okech BA, Mwobobia IK, Kamau A, Muiruri S, Mutiso N, Nyambura J, Mwatele C, Amano T, Mwandawiro CS. Use of integrated malaria management reduces malaria in Kenya. PLoS One 2008; 3:e4050. [PMID: 19115000 PMCID: PMC2603594 DOI: 10.1371/journal.pone.0004050] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Accepted: 11/12/2008] [Indexed: 11/18/2022] Open
Abstract
Background During an entomological survey in preparation for malaria control interventions in Mwea division, the number of malaria cases at the Kimbimbi sub-district hospital was in a steady decline. The underlying factors for this reduction were unknown and needed to be identified before any malaria intervention tools were deployed in the area. We therefore set out to investigate the potential factors that could have contributed to the decline of malaria cases in the hospital by analyzing the malaria control knowledge, attitudes and practices (KAP) that the residents in Mwea applied in an integrated fashion, also known as integrated malaria management (IMM). Methods Integrated Malaria Management was assessed among community members of Mwea division, central Kenya using KAP survey. The KAP study evaluated community members' malaria disease management practices at the home and hospitals, personal protection measures used at the household level and malaria transmission prevention methods relating to vector control. Concurrently, we also passively examined the prevalence of malaria parasite infection via outpatient admission records at the major referral hospital in the area. In addition we studied the mosquito vector population dynamics, the malaria sporozoite infection status and entomological inoculation rates (EIR) over an 8 month period in 6 villages to determine the risk of malaria transmission in the entire division. Results A total of 389 households in Mwea division were interviewed in the KAP study while 90 houses were surveyed in the entomological study. Ninety eight percent of the households knew about malaria disease while approximately 70% of households knew its symptoms and methods to manage it. Ninety seven percent of the interviewed households went to a health center for malaria diagnosis and treatment. Similarly a higher proportion (81%) used anti-malarial medicines bought from local pharmacies. Almost 90% of households reported owning and using an insecticide treated bed net and 81% reported buying the nets within the last 5 years. The community also used mosquito reduction measures including, in order of preference, environmental management (35%), mosquito repellent and smoke (31%) insecticide canister sprays (11%), and window and door screens (6%). These methods used by the community comprise an integrated malaria management (IMM) package. Over the last 4 years prior to this study, the malaria cases in the community hospital reduced from about 40% in 2000 to less than 10% by 2004 and by the year 2007 malaria cases decreased to zero. In addition, a one time cross-sectional malaria parasite survey detected no Plasmodium infection in 300 primary school children in the area. Mosquito vector populations were variable in the six villages but were generally lower in villages that did not engage in irrigation activities. The malaria risk as estimated by EIR remained low and varied by village and proximity to irrigation areas. The average EIR in the area was estimated at 0.011 infectious bites per person per day. Conclusions The usage of a combination of malaria control tools in an integrated fashion by residents of Mwea division might have influenced the decreased malaria cases in the district hospital and in the school children. A vigorous campaign emphasizing IMM should be adopted and expanded in Mwea division and in other areas with different eco-epidemiological patterns of malaria transmission. With sustained implementation and support from community members integrated malaria management can reduce malaria significantly in affected communities in Africa.
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Affiliation(s)
- Bernard A Okech
- Eastern and Southern Africa Centre for International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya.
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Gosling RD, Drakeley CJ, Mwita A, Chandramohan D. Presumptive treatment of fever cases as malaria: help or hindrance for malaria control? Malar J 2008; 7:132. [PMID: 18631377 PMCID: PMC2488354 DOI: 10.1186/1475-2875-7-132] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2008] [Accepted: 07/16/2008] [Indexed: 11/10/2022] Open
Abstract
Background Malaria incidence has been reported to be falling in several countries in sub-Saharan Africa in recent years. This fall appears to have started before the widespread introduction of insecticide-treated nets. In the new era of calls to eliminate and eradicate malaria in sub-Saharan Africa, exploring possible causes for this fall seem pertinent. Presentation of the hypothesis The authors explore an argument that presumptive treatment of fever cases as malaria may have played a role in reducing transmission of malaria by the prophylactic effect of antimalarials and their widespread use. This strategy, which is already in practise is termed Opportunistic Presumptive Treatment (OPT). Testing the hypothesis Further comparison of epidemiological indicators between areas with OPT and more targeted treatment is required. If data suggest a benefit of OPT, combining long acting antimalarials that have an anti-gametocyticidal activity component plus using high levels of vector control measures may reduce transmission, prevent resistant strains spreading and be easily implemented. Implications of the hypothesis OPT is practised widely by presumptive treatment of fever in health facilities and home management of fever. Improving diagnosis using rapid diagnostic tests and thus reducing the number of doses of antimalarials given may have counter intuitive effects on transmission in the context of elimination of malaria in high to moderate transmission settings.
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Affiliation(s)
- Roly D Gosling
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
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Mwai L, Gwer S, Gatakaa H, Kokwaro G, Newton C. Neurotoxicity of antimalarial drugs: a systematic review. JBI LIBRARY OF SYSTEMATIC REVIEWS 2008; 6:1-14. [PMID: 27820468 DOI: 10.11124/01938924-200806121-00005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Affiliation(s)
- Leah Mwai
- 1 Kenya Medical Research Institute (KEMRI)/ Wellcome Trust Research Programme, Centre for Geographic Medicine Research (Coast), Kilifi, Kenya. 2 Department of Pharmaceutics and Pharmacy Practice, School of Pharmacy, University of Nairobi, Nairobi, Kenya
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Antimalarial quinolones: synthesis, potency, and mechanistic studies. Exp Parasitol 2007; 118:487-97. [PMID: 18082162 DOI: 10.1016/j.exppara.2007.10.016] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2007] [Revised: 10/19/2007] [Accepted: 10/30/2007] [Indexed: 11/20/2022]
Abstract
In the present article we examine the antiplasmodial activities of novel quinolone derivatives bearing extended alkyl or alkoxy side chains terminated by a trifluoromethyl group. In the series under investigation, the IC50 values ranged from 1.2 to approximately 30 nM against chloroquine-sensitive and multidrug-resistant Plasmodium falciparum strains. Modest to significant cross-resistance was noted in evaluation of these haloalkyl- and haloalkoxyquinolones for activity against the atovaquone-resistant clinical isolate Tm90-C2B, indicating that a primary target for some of these compounds is the parasite cytochrome bc1 complex. Additional evidence to support this biochemical mechanism includes the use of oxygen biosensor plate technology to show that the quinolone derivatives block oxygen consumption by parasitized red blood cells in a fashion similar to atovaquone in side-by-side experiments. Atovaquone is extremely potent and is the only drug in clinical use that targets the Plasmodium bc1 complex, but rapid emergence of resistance to it in both mono- and combination therapy is evident and therefore additional drugs are needed to target the cytochrome bc1 complex which are active against atovaquone-resistant parasites. Our study of a number of halogenated alkyl and alkoxy 4(1H)-quinolones highlights the potential for development of "endochin-like quinolones" (ELQ), bearing an extended trifluoroalkyl moiety at the 3-position, that exhibit selective antiplasmodial effects in the low nanomolar range and inhibitory activity against chloroquine and atovaquone-resistant parasites. Further studies of halogenated alkyl- and alkoxy-quinolones may lead to the development of safe and effective therapeutics for use in treatment or prevention of malaria and other parasitic diseases.
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Anantharaman V, Iyer LM, Balaji S, Aravind L. Adhesion molecules and other secreted host-interaction determinants in Apicomplexa: insights from comparative genomics. INTERNATIONAL REVIEW OF CYTOLOGY 2007; 262:1-74. [PMID: 17631186 DOI: 10.1016/s0074-7696(07)62001-4] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Apicomplexa have developed distinctive adaptations for invading and surviving within animal cells. Here a synthetic overview of the diversity and evolutionary history of cell membrane-associated, -secreted, and -exported proteins related to apicomplexan parasitism is presented. A notable feature in this regard was the early acquisition of adhesion protein domains and glycosylation systems through lateral transfer from animals. These were utilized in multiple contexts, including invasion of host cells and parasite-specific developmental processes. Apicomplexans possess a specialized version of the ancestral alveolate extrusion machinery, the rhoptries and micronemes, which are deployed in invasion and delivery of proteins into host cells. Each apicomplexan lineage has evolved a unique spectrum of extruded proteins that modify host molecules in diverse ways. Hematozoans, in particular, appear to have evolved novel systems for export of proteins into the host organelles and cell membrane during intracellular development. These exported proteins are an important aspect of the pathogenesis of Plasmodium and Theileria, being involved in response to fever and in leukocyte proliferation respectively. The complement of apicomplexan surface proteins has primarily diversified via massive lineage-specific expansions of certain protein families, which are often coded by subtelomeric gene arrays. Many of these families have been found to be central to immune evasion. Domain shuffling and accretion have resulted in adhesins with new domain architectures. In terms of individual genes, constant selective pressures from the host immune response has resulted in extensive protein polymorphisms and gene losses. Apicomplexans have also evolved complex regulatory mechanisms controlling expression and maturation of surface proteins at the chromatin, transcriptional, posttranscriptional, and posttranslational levels. Evolutionary reconstruction suggests that the ancestral apicomplexan had thrombospondin and EGF domain adhesins, which were linked to the parasite cytoskeleton, and played a central role in invasion through formation of the moving junction. It also suggests that the ancestral parasite had O-linked glycosylation of surface proteins which was partially or entirely lost in hematozoan lineages.
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Affiliation(s)
- Vivek Anantharaman
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA
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