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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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2
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Shukla M, Rathi K, Hassam M, Yadav DK, Karnatak M, Rawat V, Verma VP. An overview on the antimalarial activity of 1,2,4-trioxanes, 1,2,4-trioxolanes and 1,2,4,5-tetraoxanes. Med Res Rev 2024; 44:66-137. [PMID: 37222435 DOI: 10.1002/med.21979] [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: 03/01/2022] [Revised: 05/04/2023] [Accepted: 05/08/2023] [Indexed: 05/25/2023]
Abstract
The demand for novel, fast-acting, and effective antimalarial medications is increasing exponentially. Multidrug resistant forms of malarial parasites, which are rapidly spreading, pose a serious threat to global health. Drug resistance has been addressed using a variety of strategies, such as targeted therapies, the hybrid drug idea, the development of advanced analogues of pre-existing drugs, and the hybrid model of resistant strains control mechanisms. Additionally, the demand for discovering new potent drugs grows due to the prolonged life cycle of conventional therapy brought on by the emergence of resistant strains and ongoing changes in existing therapies. The 1,2,4-trioxane ring system in artemisinin (ART) is the most significant endoperoxide structural scaffold and is thought to be the key pharmacophoric moiety required for the pharmacodynamic potential of endoperoxide-based antimalarials. Several derivatives of artemisinin have also been found as potential treatments for multidrug-resistant strain in this area. Many 1,2,4-trioxanes, 1,2,4-trioxolanes, and 1,2,4,5-tetraoxanes derivatives have been synthesised as a result, and many of these have shown promise antimalarial activity both in vivo and in vitro against Plasmodium parasites. As a consequence, efforts to develop a functionally straight-forward, less expensive, and vastly more effective synthetic pathway to trioxanes continue. This study aims to give a thorough examination of the biological properties and mode of action of endoperoxide compounds derived from 1,2,4-trioxane-based functional scaffolds. The present system of 1,2,4-trioxane, 1,2,4-trioxolane, and 1,2,4,5-tetraoxane compounds and dimers with potentially antimalarial activity will be highlighted in this systematic review (January 1963-December 2022).
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Affiliation(s)
- Monika Shukla
- Department of Chemistry, Banasthali University, Newai, Rajasthan, India
| | - Komal Rathi
- Department of Chemistry, Banasthali University, Newai, Rajasthan, India
| | - Mohammad Hassam
- Department of Chemistry, Chemveda Life Sciences Pvt Ltd, Hyderabad, Telangana, India
| | - Dinesh Kumar Yadav
- Department of Chemistry, Mohanlal Sukhadia University, Udaipur, Rajasthan, India
| | - Manvika Karnatak
- Department of Chemistry, Banasthali University, Newai, Rajasthan, India
| | - Varun Rawat
- School of Chemistry, Tel Aviv University, Tel Aviv, Israel
| | - Ved Prakash Verma
- Department of Chemistry, Banasthali University, Newai, Rajasthan, India
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3
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Magwaza RN, Abubaker M, Hussain B, Haley M, Couper K, Freeman S, Nirmalan NJ. Evaluation of 4-Aminoquinoline Hydrazone Analogues as Potential Leads for Drug-Resistant Malaria. Molecules 2023; 28:6471. [PMID: 37764248 PMCID: PMC10534891 DOI: 10.3390/molecules28186471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 08/31/2023] [Accepted: 09/01/2023] [Indexed: 09/29/2023] Open
Abstract
The emergence of resistance to first-line antimalarial drugs calls for the development of new therapies for drug-resistant malaria. The efficacy of quinoline-based antimalarial drugs has prompted the development of novel quinolines. A panel of 4-aminoquinoline hydrazone analogues were tested on the multidrug-resistant K1 strain of Plasmodium falciparum: IC50 values after a 48 h cycle ranged from 0.60 to 49 µM, while the 72 h cycle ranged from 0.026 to 0.219 μM. Time-course assays were carried out to define the activity of the lead compounds, which inhibited over 50% growth in 24 h and 90% growth in 72 h. Cytotoxicity assays with HepG2 cells showed IC50 values of 0.87-11.1 μM, whereas in MDBK cells, IC50 values ranged from 1.66 to 11.7 μM. High selectivity indices were observed for the lead compounds screened at 72 h on P. falciparum. Analyses of stage specificity revealed that the ring stages of the parasite life cycle were most affected. Based on antimalarial efficacy and in vitro safety profiles, lead compound 4-(2-benzylidenehydrazinyl)-6-methoxy-2-methylquinoline 2 was progressed to drug combination studies for the detection of synergism, with a combinatory index of 0.599 at IC90 for the combination with artemether, indicating a synergistic antimalarial activity. Compound 2 was screened on different strains of P. falciparum (3D7, Dd2), which maintained similar activity to K1, suggesting no cross-resistance between multidrug resistance and sensitive parasite strains. In vivo analysis with 2 showed the suppression of parasitaemia with P. yoelii NL (non-lethal)-treated mice (20 mg/kg and 5 mg/kg).
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Affiliation(s)
- Rachael N. Magwaza
- Division of Pharmacy and Optometry, School of Health Sciences, University of Manchester, Manchester M13 9PT, UK;
- School of Science, Engineering and Environment, University of Salford, Manchester M5 4WT, UK;
| | - Muna Abubaker
- School of Science, Engineering and Environment, University of Salford, Manchester M5 4WT, UK;
| | - Buthaina Hussain
- Faculty of Pharmacy, Al-Zaytoonah University of Jordan, Amman 17138, Jordan;
| | - Michael Haley
- School of Biological Sciences, Lydia Becker Institute of Immunology and Infection, University of Manchester, Manchester M13 9PT, UK; (M.H.); (K.C.)
| | - Kevin Couper
- School of Biological Sciences, Lydia Becker Institute of Immunology and Infection, University of Manchester, Manchester M13 9PT, UK; (M.H.); (K.C.)
| | - Sally Freeman
- Division of Pharmacy and Optometry, School of Health Sciences, University of Manchester, Manchester M13 9PT, UK;
| | - Niroshini J. Nirmalan
- School of Science, Engineering and Environment, University of Salford, Manchester M5 4WT, UK;
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4
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Elfahmi E, Cahyani FM, Kristianti T, Suhandono S. Transformation of Amorphadiene Synthase and Antisilencing P19 Genes into Artemisia annua L. and its Effect on Antimalarial Artemisinin Production. Adv Pharm Bull 2020; 10:464-471. [PMID: 32665907 PMCID: PMC7335994 DOI: 10.34172/apb.2020.057] [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: 08/20/2019] [Revised: 01/12/2020] [Accepted: 01/27/2020] [Indexed: 11/09/2022] Open
Abstract
Purpose: The low content of artemisinin related to the biosynthetic pathway is influenced by the role of certain enzymes in the formation of artemisinin. The regulation of genes involved in artemisinin biosynthesis through genetic engineering is a choice to enhance the content. This research aims to transform ads and p19 gene as an antisilencing into Artemisia annua and to see their effects on artemisinin production. Methods: The presence of p19 and ads genes was confirmed through polymerase chain reaction (PCR) products and sequencing analysis. The plasmids, which contain ads and/or p19 genes, were transformed into Agrobacterium tumefaciens, and then inserted into leaves and hairy roots of A. annua by vacuum and syringe infiltration methods. The successful transformation was checked through the GUS histochemical test and the PCR analysis. Artemisinin levels were measured using HPLC. Results: The percentages of the blue area on leaves by using vacuum and syringe infiltration method and on hairy roots were up to 98, 92.55%, and 99.00% respectively. The ads-p19 sample contained a higher level of artemisinin (0.18%) compared to other samples. Transformed hairy root with co-transformation of ads-p19 contained 0.095% artemisinin, where no artemisinin was found in the control hairy root. The transformation of ads and p19 genes into A. annua plant has been successfully done and could enhance the artemisinin content on the transformed leaves with ads-p19 up to 2.57 folds compared to the untransformed leaves, while for p19, cotransformed and ads were up to 2.25, 1.29, and 1.14 folds respectively. Conclusion: Antisilencing p19 gene could enhance the transformation efficiency of ads and artemisinin level in A. annua.
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Affiliation(s)
- Elfahmi Elfahmi
- School of Pharmacy, Bandung Institute of Technology, Bandung, Indonesia.,Biosciences and Biotechnology Research Center, Bandung Institute of Technology, Bandung, Indonesia
| | | | | | - Sony Suhandono
- School of Life Sciences and Technology, Bandung Institute of Technology, Bandung, Indonesia
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5
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Tiwari MK, Chaudhary S. Artemisinin-derived antimalarial endoperoxides from bench-side to bed-side: Chronological advancements and future challenges. Med Res Rev 2020; 40:1220-1275. [PMID: 31930540 DOI: 10.1002/med.21657] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 11/21/2019] [Accepted: 12/17/2019] [Indexed: 12/14/2022]
Abstract
According to WHO World Malaria Report (2018), nearly 219 million new cases of malaria occurred and a total no. of 435 000 people died in 2017 due to this infectious disease. This is due to the rapid spread of parasite-resistant strains. Artemisinin (ART), a sesquiterpene lactone endoperoxide isolated from traditional Chinese herb Artemisia annua, has been recognized as a novel class of antimalarial drugs. The 2015 "Nobel Prize in Physiology or Medicine" was given to Prof Dr Tu Youyou for the discovery of ART. Hence, ART is termed as "Nobel medicine." The present review article accommodates insights from the chronological advancements and direct statistics witnessed during the past 48 years (1971-2019) in the medicinal chemistry of ART-derived antimalarial endoperoxides, and their clinical utility in malaria chemotherapy and drug discovery.
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Affiliation(s)
- Mohit K Tiwari
- Laboratory of Organic and Medicinal Chemistry, Department of Chemistry, Malaviya National Institute of Technology Jaipur, Jaipur, India
| | - Sandeep Chaudhary
- Laboratory of Organic and Medicinal Chemistry, Department of Chemistry, Malaviya National Institute of Technology Jaipur, Jaipur, India
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6
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Dambach P, Baernighausen T, Traoré I, Ouedraogo S, Sié A, Sauerborn R, Becker N, Louis VR. Reduction of malaria vector mosquitoes in a large-scale intervention trial in rural Burkina Faso using Bti based larval source management. Malar J 2019; 18:311. [PMID: 31521176 PMCID: PMC6744650 DOI: 10.1186/s12936-019-2951-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 09/07/2019] [Indexed: 11/21/2022] Open
Abstract
Background Malaria remains one of the most important causes of morbidity and death in sub-Saharan Africa. Along with early diagnosis and treatment of malaria cases and intermittent preventive treatment in pregnancy (IPTp), vector control is an important tool in the reduction of new cases. Alongside the use of long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS), targeting the vector larvae with biological larvicides, such as Bacillus thuringiensis israelensis (Bti) is gaining importance as a means of reducing the number of mosquito larvae before they emerge to their adult stage. This study presents data corroborating the entomological impact of such an intervention in a rural African environment. Methods The study extended over 2 years and researched the impact of biological larviciding with Bti on malaria mosquitoes that were caught indoors and outdoors of houses using light traps. The achieved reductions in female Anopheles mosquitoes were calculated for two different larviciding choices using a regression model. Results In villages that received selective treatment of the most productive breeding sites, the number of female Anopheles spp. dropped by 61% (95% CI 54–66%) compared to the pre-intervention period. In villages in which all breeding sites were treated, the number of female Anopheles spp. was reduced by 70% (95% CI 64–74%) compared to the pre-intervention period. Conclusion It was shown that malaria vector abundance can be dramatically reduced through larviciding of breeding habitats and that, in many geographical settings, they are a viable addition to current malaria control measures.
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Affiliation(s)
- Peter Dambach
- Institute of Public Health, University Hospital Heidelberg, 69120, Heidelberg, Germany.
| | - Till Baernighausen
- Institute of Public Health, University Hospital Heidelberg, 69120, Heidelberg, Germany
| | - Issouf Traoré
- Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso
| | | | - Ali Sié
- Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso
| | - Rainer Sauerborn
- Institute of Public Health, University Hospital Heidelberg, 69120, Heidelberg, Germany
| | - Norbert Becker
- German Mosquito Control Association (KABS), 67346, Speyer, Germany
| | - Valérie R Louis
- Institute of Public Health, University Hospital Heidelberg, 69120, Heidelberg, Germany
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7
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Tiwari MK, Yadav DK, Chaudhary S. Recent Developments in Natural Product Inspired Synthetic 1,2,4- Trioxolanes (Ozonides): An Unusual Entry into Antimalarial Chemotherapy. Curr Top Med Chem 2019; 19:831-846. [DOI: 10.2174/1568026619666190412104042] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 03/11/2019] [Accepted: 03/14/2019] [Indexed: 11/22/2022]
Abstract
According to WHO “World health statistics 2018”, malaria alongside acute respiratory infections
and diarrhoea, is one of the major infectious disease causing children’s death in between the
age of 1-5 years. Similarly, according to another report (2016) malaria accounts for approximately
3.14% of the total disease burden worldwide. Although malaria has been widely eradicated in many
parts of the world, the global number of cases continues to rise due to the rapid spread of malaria parasites
that are resistant to antimalarial drugs. Artemisinin (8), a major breakthrough in the antimalarial
chemotherapy was isolated from the plant Artemisia annua in 1972. Its semi-synthetic derivatives such
as artemether (9), arteether (10), and artesunic acid (11) are quite effective against multi-drug resistant
malaria strains and are currently the drug of choice for the treatment of malaria. Inspite of exhibiting
excellent antimalarial activity by artemisinin (8) and its derivatives, parallel programmes for the discovery
of novel natural and synthetic peroxides were also the area of investigation of medicinal chemists
all over the world. In these continuous efforts of extensive research, natural ozonide (1,2,4-
trioxolane) was isolated from Adiantum monochlamys (Pteridaceae) and Oleandra wallichii (Davalliaceae)
in 1976. These naturally occurring stable ozonides inspired chemists to investigate this novel
class for antimalarial chemotherapy. The first identification of unusually stable synthetic antimalarial
1,2,4-trioxolanes was reported in 1992. Thus, an unusual entry of ozonides in the field of antimalarial
chemotherapy had occurred in the early nineties. This review highlights the recent advancements and
historical developments observed during the past 42 years (1976-2018) focusing mainly on important
ventures of the antimalarial 1,2,4-trioxolanes (ozonides).
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Affiliation(s)
- Mohit K. Tiwari
- Laboratory of Organic and Medicinal Chemistry, Department of Chemistry, Malaviya National Institute of Technology Jaipur, Jawaharlal Nehru Marg, Jaipur-302017, India
| | - Dharmendra K. Yadav
- College of Pharmacy, Gachon University of Medicine and Science, Hambakmoeiro 191, Yeonsu-gu, Incheon city, 406-799, Korea
| | - Sandeep Chaudhary
- Laboratory of Organic and Medicinal Chemistry, Department of Chemistry, Malaviya National Institute of Technology Jaipur, Jawaharlal Nehru Marg, Jaipur-302017, India
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8
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Mazigo HD, Mboera LEG, Rumisha SF, Kweka EJ. Malaria mosquito control in rice paddy farms using biolarvicide mixed with fertilizer in Tanzania: semi-field experiments. Malar J 2019; 18:226. [PMID: 31286986 PMCID: PMC6615286 DOI: 10.1186/s12936-019-2861-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 07/03/2019] [Indexed: 01/21/2023] Open
Abstract
Background The wide distribution of malaria mosquito breeding sites within tropical environments limits the mosquito larval source management efforts to control malaria. Rice farming contributes substantially in supporting malaria mosquito productivity in tropical countries. To overcome this challenge, this study was carried out to determine the effect of applying a mixture of biolarvicide and fertilizer on mosquito larvae density in rice farms under semi-field conditions in Tanzania. Methods A semi-field experiment was designed to determine the timing of application of a biolarvicide, Bacillus thuringiensis israelensis (Bti) and fertilizer (di-ammonium phosphate-DAP or urea) and assess their effect on mosquito larvae density and rice grain outputs. The experiment had five blocks (4 treatment arms and one control arm) and each had four replicates. Treatment arms had different intervals of days between treatments for mixtures of fertilizer and biolarvicides. The dosages used were 10 g of Bti/16 M2 and 160 g of DAP/Urea/16 m2. Results In overall, the intervention blocks (with biolarvicide) had lowest mean mosquito larvae abundance compared to control block (F = 22.42, P < 0.001). Similarly, the control arm maintained highest density of Anopheles gambiae sensu lato larvae compared to interventions blocks (F = 21.6, P < 0.001). The best determined timing for application of Bti was in 7 and in 10 days (F = 3.753, P < 0.001). There was neither significant different in mean rice grain harvest per ten panicle (F = 1.453, P = 0.27) nor mean difference in rice grain harvest (F = 1.479, P = 0.26) per intervention arms. Conclusion The findings of this study have shown that application of a mixture of Bti and fertilizer have impact on both mosquito larvae density and maintaining yield rice harvest. Thus, application of a combination of biolarvicide and fertilizer can be an alternative approach in malaria mosquito intervention among rice farming communities of rural Tanzania.
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Affiliation(s)
- Humphrey D Mazigo
- Department of Medical Parasitology, School of Medicine, Catholic University of Health and Allied Sciences-Bugando, P.O. Box 1464, Mwanza, Tanzania
| | - Leonard E G Mboera
- SACIDS Foundation for One Health, Sokoine University of Agriculture, P.O. Box 3297, Chuo Kikuu, Morogoro, Tanzania
| | - Susan F Rumisha
- National Institute for Medical Research, Headquarters, P.O. Box 9653, Dar Es Salaam, Tanzania
| | - Eliningaya J Kweka
- Department of Medical Parasitology, School of Medicine, Catholic University of Health and Allied Sciences-Bugando, P.O. Box 1464, Mwanza, Tanzania. .,Division of Livestock and Human Diseases Vector Control, Mosquito Section, Tropical Pesticides Research Institute, P.O. Box 3024, Arusha, Tanzania.
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9
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Kumari A, Karnatak M, Singh D, Shankar R, Jat JL, Sharma S, Yadav D, Shrivastava R, Verma VP. Current scenario of artemisinin and its analogues for antimalarial activity. Eur J Med Chem 2018; 163:804-829. [PMID: 30579122 DOI: 10.1016/j.ejmech.2018.12.007] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Revised: 11/29/2018] [Accepted: 12/02/2018] [Indexed: 11/17/2022]
Abstract
Human malaria, one of the most striking, reemerging infectious diseases, is caused by several types of Plasmodium parasites. Whilst advances have been made in lowering the numbers of cases and deaths, it is clear that a strategy based solely on disease control year on year, without reducing transmission and ultimately eradicating the parasite, is unsustainable. Natural products have served as a template for the design and development of antimalarial drugs currently in the clinic or in the development phase. Artemisinin combine potent, rapid antimalarial activity with a wide therapeutic index and an absence of clinically important resistance. The alkylating ability of artemisinin and its semi-synthetic analogues toward heme related to their antimalarial efficacy are underlined. Although impressive results have already been achieved in malaria research, more systematization and concentration of efforts are required if real breakthroughs are to be made. This review will concisely cover the clinical, preclinical antimalarial and current updates in artemisinin based antimalarial drugs. Diverse classes of semi-synthetic analogs of artemisinin reported in the last decade have also been extensively studied. The experience gained in this respect is discussed.
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Affiliation(s)
- Akriti Kumari
- Department of Chemistry, Banasthali University, Banasthali Newai, 304022, Rajasthan, India
| | - Manvika Karnatak
- Department of Chemistry, Banasthali University, Banasthali Newai, 304022, Rajasthan, India
| | - Davinder Singh
- Bio-Organic Chemistry Division, CSIR-Indian Institute of Integrative Medicine, Jammu, 180001, Jammu and Kashmir, India
| | - Ravi Shankar
- Bio-Organic Chemistry Division, CSIR-Indian Institute of Integrative Medicine, Jammu, 180001, Jammu and Kashmir, India
| | - Jawahar L Jat
- Department of Applied Chemistry, BabaSaheb Bhimrao Ambedkar University (A Central University), Vidya Vihar Raebareli Road, Lucknow, 226025, India
| | - Siddharth Sharma
- Department of Chemistry, Mohanlal Sukhadia University, Udaipur, 313001, India
| | - Dinesh Yadav
- Department of Chemistry, Mohanlal Sukhadia University, Udaipur, 313001, India
| | - Rahul Shrivastava
- Department of Chemistry, Manipal University Jaipur, Jaipur, 303007, India
| | - Ved Prakash Verma
- Department of Chemistry, Banasthali University, Banasthali Newai, 304022, Rajasthan, India.
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10
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Liu BB, Chu XQ, Liu H, Yin L, Wang SY, Ji SJ. Aqueous Reaction of Alcohols, Organohalides, and Odorless Sodium Thiosulfate under Transition-Metal-Free Conditions: Synthesis of Unsymmetrical Aryl Sulfides via Dual C–S Bond Formation. J Org Chem 2017; 82:10174-10180. [DOI: 10.1021/acs.joc.7b01653] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Bei-Bei Liu
- Key
Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry,
Chemical Engineering and Materials Science and Collaborative Innovation
Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123, P. R. China
| | - Xue-Qiang Chu
- Key
Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry,
Chemical Engineering and Materials Science and Collaborative Innovation
Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123, P. R. China
| | - Huan Liu
- Key
Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry,
Chemical Engineering and Materials Science and Collaborative Innovation
Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123, P. R. China
| | - Ling Yin
- Department
of Chemistry and Chemical Engineering, Jining University, Qufu 273155, P. R. China
| | - Shun-Yi Wang
- Key
Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry,
Chemical Engineering and Materials Science and Collaborative Innovation
Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123, P. R. China
| | - Shun-Jun Ji
- Key
Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry,
Chemical Engineering and Materials Science and Collaborative Innovation
Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123, P. R. China
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11
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Parhizgar AR, Tahghighi A. Introducing New Antimalarial Analogues of Chloroquine and Amodiaquine: A Narrative Review. IRANIAN JOURNAL OF MEDICAL SCIENCES 2017; 42:115-128. [PMID: 28360437 PMCID: PMC5366359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 05/02/2016] [Accepted: 06/05/2016] [Indexed: 11/03/2022]
Abstract
Antimalarial drugs with the 4-aminoquinoline scaffold such as the important drugs, chloroquine (CQ) and amodiaquine (AQ), have been used to prevent and treat malaria for many years. The importance of these drugs is related to their simple usage, high efficacy, affordability, and cost-effectiveness of their synthesis. In recent years, with the spread of parasite resistance to CQ and cross-resistance to its other analogues have decreased their consumption in many geographical areas. On the other hand, AQ is an effective antimalarial drug which its usage has been restricted due to hepatic and hematological toxicities. The significance of the quinoline ring at quinoline-based antimalarial drugs has prompted research centers and pharmaceutical companies to focus on the design and synthesis of new analogues of these drugs, especially CQ and AQ analogues. Accordingly, various derivatives have been synthesized and evaluated in vitro and in vivo against the resistant strains of the malaria parasite to solve the problem of drug resistance. Also, the pharmacokinetic properties of these compounds have been evaluated to augment their efficacy and diminish their toxicity. Some of these analogues are currently in clinical and preclinical development. Consequently, the recent researches showed yet 4-aminoquinoline scaffold is active moiety in new compounds with antiplasmodial activity. Hence, the aim of this review article is to introduce of the novel synthetic analogues of CQ and AQ, which may constitute the next generation of antimalarial drugs with the 4-aminoquinoline scaffold.
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Affiliation(s)
- Arezoo Rafiee Parhizgar
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran
- Department of Medicinal Chemistry, Pharmaceutical Sciences Branch, Islamic Azad University, Tehran, Iran
| | - Azar Tahghighi
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran
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Rudrapal M, Chetia D. Endoperoxide antimalarials: development, structural diversity and pharmacodynamic aspects with reference to 1,2,4-trioxane-based structural scaffold. DRUG DESIGN DEVELOPMENT AND THERAPY 2016; 10:3575-3590. [PMID: 27843298 PMCID: PMC5098533 DOI: 10.2147/dddt.s118116] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Malaria disease continues to be a major health problem worldwide due to the emergence of multidrug-resistant strains of Plasmodium falciparum. In recent days, artemisinin (ART)-based drugs and combination therapies remain the drugs of choice for resistant P. falciparum malaria. However, resistance to ART-based drugs has begun to appear in some parts of the world. Endoperoxide compounds (natural/semisynthetic/synthetic) representing a huge number of antimalarial agents possess a wide structural diversity with a desired antimalarial effectiveness against resistant P. falciparum malaria. The 1,2,4-trioxane ring system lacking the lactone ring that constitutes the most important endoperoxide structural scaffold is believed to be the key pharmacophoric moiety and is primarily responsible for the pharmacodynamic potential of endoperoxide-based antimalarials. Due to this reason, research into endoperoxide, particularly 1,2,4-trioxane-, 1,2,4-trioxolane- and 1,2,4,5-teraoxane-based scaffolds, has gained significant interest in recent years for developing antimalarial drugs against resistant malaria. In this paper, a comprehensive effort has been made to review the development of endoperoxide antimalarials from traditional antimalarial leads (natural/semisynthetic) and structural diversity of endoperoxide molecules derived from 1,2,4-trioxane-, 1,2,4-trioxolane- and 1,2,4,5-teraoxane-based structural scaffolds, including their chimeric (hybrid) molecules, which are newer and potent antimalarial agents.
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Affiliation(s)
- Mithun Rudrapal
- Department of Pharmaceutical Sciences, Dibrugarh University, Dibrugarh, India
| | - Dipak Chetia
- Department of Pharmaceutical Sciences, Dibrugarh University, Dibrugarh, India
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Narrative review of current context of malaria and management strategies in Uganda (Part I). Acta Trop 2015; 152:252-268. [PMID: 26257070 DOI: 10.1016/j.actatropica.2015.07.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 07/28/2015] [Accepted: 07/31/2015] [Indexed: 01/26/2023]
Abstract
In accordance with international targets, the Uganda National Malaria Control Strategic Plan established specific targets to be achieved by 2010. For children under five, this included increasing the number of children sleeping under mosquito nets and those receiving a first-line antimalarial to 85%, and decreasing case fatality to 2%. This narrative review offers contextual information relevant to malaria management in Uganda since the advent of artemisinin combination therapy (ACT) as first-line antimalarial treatment in 2004. A comprehensive search using key words and phrases was conducted using the web search engines Google and Google Scholar, as well as the databases of PubMed, ERIC, EMBASE, CINAHL, OvidSP (MEDLINE), PSYC Info, Springer Link, Cochrane Central Register of Controlled Trials (CENTRAL), and Cochrane Database of Systematic Reviews were searched. A total of 147 relevant international and Ugandan literature sources meeting the inclusion criteria were included. This review provides an insightful understanding on six topic areas: global and local priorities, malarial pathology, disease burden, malaria control, treatment guidelines for uncomplicated malaria, and role of the health system in accessing antimalarial medicines. Plasmodium falciparum remains the most common cause of malaria in Uganda, with children under five being most vulnerable due to their underdeveloped immunity. While international efforts to scale up malaria control measures have resulted in considerable decline in malaria incidence and mortality in several regions of sub-Saharan Africa, this benefit has yet to be substantiated for Uganda. At the local level, key initiatives have included implementation of a new antimalarial drug policy in 2004 and strengthening of government health systems and programs. Examples of such programs include removal of user fees, training of frontline health workers, providing free ACT from government systems and subsidized ACT from licensed private outlets, and introduction of the integrated community case management program to bring diagnostics and treatment for malaria, pneumonia and diarrhea closer to the community. However despite notable efforts, Uganda is far from achieving its 2010 targets. Several challenges in the delivery of care and treatment remain, with those most vulnerable and living in rural settings remaining at greatest risk from malaria morbidity and mortality.
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McConville M, Fernández J, Angulo-Barturen Í, Bahamontes-Rosa N, Ballell-Pages L, Castañeda P, de Cózar C, Crespo B, Guijarro L, Jiménez-Díaz MB, Martínez-Martínez MS, de Mercado J, Santos-Villarejo Á, Sanz LM, Frigerio M, Washbourn G, Ward SA, Nixon GL, Biagini GA, Berry NG, Blackman MJ, Calderón F, O'Neill PM. Carbamoyl Triazoles, Known Serine Protease Inhibitors, Are a Potent New Class of Antimalarials. J Med Chem 2015. [PMID: 26222445 DOI: 10.1021/acs.jmedchem.5b00434] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Screening of the GSK corporate collection, some 1.9 million compounds, against Plasmodium falciparum (Pf), revealed almost 14000 active hits that are now known as the Tres Cantos Antimalarial Set (TCAMS). Followup work by Calderon et al. clustered and computationally filtered the TCAMS through a variety of criteria and reported 47 series containing a total of 522 compounds. From this enhanced set, we identified the carbamoyl triazole TCMDC-134379 (1), a known serine protease inhibitor, as an excellent starting point for SAR profiling. Lead optimization of 1 led to several molecules with improved antimalarial potency, metabolic stabilities in mouse and human liver microsomes, along with acceptable cytotoxicity profiles. Analogue 44 displayed potent in vitro activity (IC50 = 10 nM) and oral activity in a SCID mouse model of Pf infection with an ED50 of 100 and ED90 of between 100 and 150 mg kg(-1), respectively. The results presented encourage further investigations to identify the target of these highly active compounds.
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Affiliation(s)
- Matthew McConville
- Tres Cantos Medicines Development Campus, DDW, GlaxoSmithKline , Severo Ochoa 2, 28760 Tres Cantos, Spain
| | - Jorge Fernández
- Tres Cantos Medicines Development Campus, DDW, GlaxoSmithKline , Severo Ochoa 2, 28760 Tres Cantos, Spain
| | - Íñigo Angulo-Barturen
- Tres Cantos Medicines Development Campus, DDW, GlaxoSmithKline , Severo Ochoa 2, 28760 Tres Cantos, Spain
| | - Noemi Bahamontes-Rosa
- Tres Cantos Medicines Development Campus, DDW, GlaxoSmithKline , Severo Ochoa 2, 28760 Tres Cantos, Spain
| | - Lluis Ballell-Pages
- Tres Cantos Medicines Development Campus, DDW, GlaxoSmithKline , Severo Ochoa 2, 28760 Tres Cantos, Spain
| | - Pablo Castañeda
- Tres Cantos Medicines Development Campus, DDW, GlaxoSmithKline , Severo Ochoa 2, 28760 Tres Cantos, Spain
| | - Cristina de Cózar
- Tres Cantos Medicines Development Campus, DDW, GlaxoSmithKline , Severo Ochoa 2, 28760 Tres Cantos, Spain
| | - Benigno Crespo
- Tres Cantos Medicines Development Campus, DDW, GlaxoSmithKline , Severo Ochoa 2, 28760 Tres Cantos, Spain
| | - Laura Guijarro
- Tres Cantos Medicines Development Campus, DDW, GlaxoSmithKline , Severo Ochoa 2, 28760 Tres Cantos, Spain
| | - María Belén Jiménez-Díaz
- Tres Cantos Medicines Development Campus, DDW, GlaxoSmithKline , Severo Ochoa 2, 28760 Tres Cantos, Spain
| | - Maria S Martínez-Martínez
- Tres Cantos Medicines Development Campus, DDW, GlaxoSmithKline , Severo Ochoa 2, 28760 Tres Cantos, Spain
| | - Jaime de Mercado
- Tres Cantos Medicines Development Campus, DDW, GlaxoSmithKline , Severo Ochoa 2, 28760 Tres Cantos, Spain
| | - Ángel Santos-Villarejo
- Tres Cantos Medicines Development Campus, DDW, GlaxoSmithKline , Severo Ochoa 2, 28760 Tres Cantos, Spain
| | - Laura M Sanz
- Tres Cantos Medicines Development Campus, DDW, GlaxoSmithKline , Severo Ochoa 2, 28760 Tres Cantos, Spain
| | - Micol Frigerio
- Department of Chemistry, University of Liverpool , Liverpool L69 7ZD, United Kingdom
| | - Gina Washbourn
- Department of Chemistry, University of Liverpool , Liverpool L69 7ZD, United Kingdom
| | - Stephen A Ward
- Liverpool School of Tropical Medicine , Pembroke Place, Liverpool L3 5QA, United Kingdom
| | - Gemma L Nixon
- Department of Chemistry, University of Liverpool , Liverpool L69 7ZD, United Kingdom
| | - Giancarlo A Biagini
- Liverpool School of Tropical Medicine , Pembroke Place, Liverpool L3 5QA, United Kingdom
| | - Neil G Berry
- Department of Chemistry, University of Liverpool , Liverpool L69 7ZD, United Kingdom
| | - Michael J Blackman
- Division of Parasitology, MRC National Institute for Medical Research , Mill Hill, London NW7 1AA, United Kingdom
| | - Félix Calderón
- Tres Cantos Medicines Development Campus, DDW, GlaxoSmithKline , Severo Ochoa 2, 28760 Tres Cantos, Spain
| | - Paul M O'Neill
- Department of Chemistry, University of Liverpool , Liverpool L69 7ZD, United Kingdom
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Larionov OV, Stephens D, Mfuh A, Chavez G. Direct, catalytic, and regioselective synthesis of 2-alkyl-, aryl-, and alkenyl-substituted N-heterocycles from N-oxides. Org Lett 2014; 16:864-7. [PMID: 24410049 DOI: 10.1021/ol403631k] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A one-step transformation of heterocyclic N-oxides to 2-alkyl-, aryl-, and alkenyl-substituted N-heterocycles is described. The success of this broad-scope methodology hinges on the combination of copper catalysis and activation by lithium fluoride or magnesium chloride. The utility of this method for the late-stage modification of complex N-heterocycles is exemplified by facile syntheses of new structural analogues of several antimalarial, antimicrobial, and fungicidal agents.
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Affiliation(s)
- Oleg V Larionov
- Department of Chemistry, University of Texas at San Antonio , One UTSA Circle, San Antonio, Texas 78249, United States
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A Bassyouni F, Abu-Baker SM, Mahmoud K, Moharam M, El-Nakkady SS, Rehim MA. Synthesis and biological evaluation of some new triazolo[1,5-a]quinoline derivatives as anticancer and antimicrobial agents. RSC Adv 2014. [DOI: 10.1039/c3ra46961a] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Peters W, Stewart LB, Robinson BL. The chemotherapy of rodent malaria. LXIII. Drug combinations to impede the selection of drug resistance, part 6: the potential value of chlorproguanil and dapsone in combination, and with the addition of artesunate. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2013; 99:457-72. [PMID: 16004705 DOI: 10.1179/136485905x51274] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Resistance is readily produced in rodent malaria using the single-dose, '2%-relapse technique' (2%RT) against the individual compounds chlorproguanil (CPG), chlorcycloguanil (CCG), cycloguanil, dapsone (DDS) and artesunate (ASN). Using the '4-day test', a low level of synergism or a simple additional action between CPG and DDS was observed with multiple dosing of these two compounds in a combination. Resistance to a 1 : 3 combination of CPG-DDS was selected in each of three parasite lines: Plasmodium berghei NK65, P. yoelii ssp. NS and P. chabaudi AS. Of these lines, P. chabaudi AS was found to be the most sensitive to the 1 : 3 combination in the 2%RT (and was also previously found to be the most sensitive when the compounds were used individually). Plasmodium chabaudi AS was also the line found most sensitive to a 7 : 21 : 300 combination of CPG-DDS-ASN (CDA). In mice infected with P. chabaudi AS, compared with the use of the individual components, the CPG-DDS combination only a gave a modest level of protection (as indicated by the increase in the time required to select resistance in the 2%RT) but the triple CDA combination was totally effective over the duration of the experiment. New pharmacokinetic data to be reported elsewhere indicate, however, that the antimalarial action of CPG in mice is exerted by a mechanism that is not associated with the drug's conversion to the antifolate triazine, CCG. The question thus arises as to how, in the present model, the protective action of CDA was effected. The present results nevertheless reinforce the hypothesis that a CDA combination, appropriately proportioned for human use, should be of practical value, in protecting the individual components, when used for the treatment of multidrug-resistant P. falciparum, and possibly other Plasmodium species, in endemic areas. Clinical trials, both with a CPG-DDS combination (Lapdap) and CDA, are currently under way in tropical Africa. Further studies are now required to determine whether DDS, CPG or an as-yet unidentified metabolite of CPG interact with ASN, and whether a simple double combination of ASN with one or other of these would be as protective, against the selection of resistance, as CDA.
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Affiliation(s)
- W Peters
- Centre for Tropical Antiprotozoal Chemotherapy, Y Block, Northwick Park Institute for Medical Research, Harrow, UK.
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Singh P, Singh P, Kumar M, Gut J, Rosenthal PJ, Kumar K, Kumar V, Mahajan MP, Bisetty K. Synthesis, docking and in vitro antimalarial evaluation of bifunctional hybrids derived from β-lactams and 7-chloroquinoline using click chemistry. Bioorg Med Chem Lett 2012; 22:57-61. [DOI: 10.1016/j.bmcl.2011.11.082] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2011] [Revised: 11/16/2011] [Accepted: 11/19/2011] [Indexed: 10/15/2022]
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Diakite M, Achidi EA, Achonduh O, Craik R, Djimde AA, Evehe MSB, Green A, Hubbart C, Ibrahim M, Jeffreys A, Khan BK, Kimani F, Kwiatkowski DP, Mbacham WF, Jezan SO, Ouedraogo JB, Rockett K, Rowlands K, Tagelsir N, Tekete MM, Zongo I, Ranford-Cartwright LC. Host candidate gene polymorphisms and clearance of drug-resistant Plasmodium falciparum parasites. Malar J 2011; 10:250. [PMID: 21867552 PMCID: PMC3177816 DOI: 10.1186/1475-2875-10-250] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 08/25/2011] [Indexed: 12/02/2022] Open
Abstract
Background Resistance to anti-malarial drugs is a widespread problem for control programmes for this devastating disease. Molecular tests are available for many anti-malarial drugs and are useful tools for the surveillance of drug resistance. However, the correlation of treatment outcome and molecular tests with particular parasite markers is not perfect, due in part to individuals who are able to clear genotypically drug-resistant parasites. This study aimed to identify molecular markers in the human genome that correlate with the clearance of malaria parasites after drug treatment, despite the drug resistance profile of the protozoan as predicted by molecular approaches. Methods 3721 samples from five African countries, which were known to contain genotypically drug resistant parasites, were analysed. These parasites were collected from patients who subsequently failed to clear their infection following drug treatment, as expected, but also from patients who successfully cleared their infections with drug-resistant parasites. 67 human polymorphisms (SNPs) on 17 chromosomes were analysed using Sequenom's mass spectrometry iPLEX gold platform, to identify regions of the human genome, which contribute to enhanced clearance of drug resistant parasites. Results An analysis of all data from the five countries revealed significant associations between the phenotype of ability to clear drug-resistant Plasmodium falciparum infection and human immune response loci common to all populations. Overall, three SNPs showed a significant association with clearance of drug-resistant parasites with odds ratios of 0.76 for SNP rs2706384 (95% CI 0.71-0.92, P = 0.005), 0.66 for SNP rs1805015 (95% CI 0.45-0.97, P = 0.03), and 0.67 for SNP rs1128127 (95% CI 0.45-0.99, P = 0.05), after adjustment for possible confounding factors. The first two SNPs (rs2706384 and rs1805015) are within loci involved in pro-inflammatory (interferon-gamma) and anti-inflammatory (IL-4) cytokine responses. The third locus encodes a protein involved in the degradation of misfolded proteins within the endoplasmic reticulum, and its role, if any, in the clearance phenotype is unclear. Conclusions The study showed significant association of three loci in the human genome with the ability of parasite to clear drug-resistant P. falciparum in samples taken from five countries distributed across sub-Saharan Africa. Both SNP rs2706384 and SNP1805015 have previously been reported to be associated with risk of malaria infection in African populations. The loci are involved in the Th1/Th2 balance, and the association of SNPs within these genes suggests a key role for antibody in the clearance of drug-resistant parasites. It is possible that patients able to clear drug-resistant infections have an enhanced ability to control parasite growth.
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Affiliation(s)
- Mahamadou Diakite
- Malaria Research and Training Centre, Faculty of Medicine, Pharmacy and Odontostomatology, University of Bamako, Mali.
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Miller MJ, Walz AJ, Zhu H, Wu C, Moraski G, Möllmann U, Tristani EM, Crumbliss AL, Ferdig MT, Checkley L, Edwards RL, Boshoff HI. Design, synthesis, and study of a mycobactin-artemisinin conjugate that has selective and potent activity against tuberculosis and malaria. J Am Chem Soc 2011; 133:2076-9. [PMID: 21275374 PMCID: PMC3045749 DOI: 10.1021/ja109665t] [Citation(s) in RCA: 109] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Although the antimalarial agent artemisinin itself is not active against tuberculosis, conjugation to a mycobacterial-specific siderophore (microbial iron chelator) analogue induces significant and selective antituberculosis activity, including activity against multi- and extensively drug-resistant strains of Mycobacterium tuberculosis. The conjugate also retains potent antimalarial activity. Physicochemical and whole-cell studies indicated that ferric-to-ferrous reduction of the iron complex of the conjugate initiates the expected bactericidal Fenton-type radical chemistry on the artemisinin component. Thus, this "Trojan horse" approach demonstrates that new pathogen-selective therapeutic agents in which the iron component of the delivery vehicle also participates in triggering the antibiotic activity can be generated. The result is that one appropriate conjugate has potent and selective activity against two of the most deadly diseases in the world.
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Affiliation(s)
- Marvin J Miller
- Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, Indiana 46556, United States.
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Chandel S, Bagai U. Screening of antiplasmodial efficacy of Ajuga bracteosa Wall ex. Benth. Parasitol Res 2011; 108:801-5. [PMID: 21264476 DOI: 10.1007/s00436-011-2250-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Accepted: 10/06/2010] [Indexed: 11/26/2022]
Abstract
The rising problem of Plasmodium resistance to the classical antimalarial drugs stresses the need to look for newer antiplasmodial components with effective and new mode of action. In the present study, the traditional medicinal plant Ajuga bracteosa has been screened for its antiplasmodial efficacy. The extract was found to possess significant in vitro antiplasmodial efficacy with an IC(50) of 10.0 μg/ml. Thus, the extract was further evaluated for its in vivo schizontocidal activity and efficacy in terms of survival time in Plasmodium berghei infected BALB/c mice. The extract at 250, 500, and 750 mg/kg/day exhibited significant (p<0.0001) blood schizontocidal activity during established infection with enhanced mean survival time comparable to that of standard drug chloroquine, 5 mg/kg/day. The significant schizontocidal activity and enhanced mean survival time of mice stress the need to identify and characterize active antiplasmodial principle from this plant.
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Affiliation(s)
- Sanjeev Chandel
- Parasitology Laboratory, Department of Zoology, Panjab University, Chandigarh, 160014, India.
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Interspecies comparison of the pharmacokinetics and oral bioavailability of 99-357, a potent synthetic trioxane antimalarial compound. Eur J Pharm Sci 2010; 41:312-9. [PMID: 20599503 DOI: 10.1016/j.ejps.2010.06.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2009] [Revised: 06/12/2010] [Accepted: 06/24/2010] [Indexed: 11/24/2022]
Abstract
The pharmacokinetic data obtained in lower animals is of considerable importance in drug discovery and development. The objective of the present study was to generate in vitro and in vivo preclinical pharmacokinetic data of 99-357, a synthetic trioxane antimalarial, in rats and rabbits and to scale-up the data in order to apply for further studies. The pharmacokinetic profile of 99-357 was investigated after both intravenous and oral dose in rats and rabbits. Oral studies were carried out at three dose levels 6, 12 and 24mg/kg in rats while in rabbit only one dose level was selected. Both compartmental and non-compartmental approaches were used to calculate the pharmacokinetic parameters following intravenous and oral doses in both the species. The clearance in rat and rabbit was 45-57% and 60-67% respectively of hepatic blood flow. The plasma protein binding in rats was approximately 75%. In vitro studies showed high RBC partitioning and low to moderate hepatic clearance. Linearity was observed in terms of dose and AUCs suggesting linear pharmacokinetics at the dose levels studied in rats. The oral bioavailability of compound 99-357 in rat and rabbit at 12mg/kg dose level was comparable and 39% and 41% respectively.
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Dowling DP, Ilies M, Olszewski KL, Portugal S, Mota MM, Llinás M, Christianson DW. Crystal structure of arginase from Plasmodium falciparum and implications for L-arginine depletion in malarial infection . Biochemistry 2010; 49:5600-8. [PMID: 20527960 DOI: 10.1021/bi100390z] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The 2.15 A resolution crystal structure of arginase from Plasmodium falciparum, the parasite that causes cerebral malaria, is reported in complex with the boronic acid inhibitor 2(S)-amino-6-boronohexanoic acid (ABH) (K(d) = 11 microM). This is the first crystal structure of a parasitic arginase. Various protein constructs were explored to identify an optimally active enzyme form for inhibition and structural studies and to probe the structure and function of two polypeptide insertions unique to malarial arginase: a 74-residue low-complexity region contained in loop L2 and an 11-residue segment contained in loop L8. Structural studies indicate that the low-complexity region is largely disordered and is oriented away from the trimer interface; its deletion does not significantly compromise enzyme activity. The loop L8 insertion is located at the trimer interface and makes several intra- and intermolecular interactions important for enzyme function. In addition, we also demonstrate that arg- Plasmodium berghei sporozoites show significantly decreased liver infectivity in vivo. Therefore, inhibition of malarial arginase may serve as a possible candidate for antimalarial therapy against liver-stage infection, and ABH may serve as a lead for the development of inhibitors.
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Affiliation(s)
- Daniel P Dowling
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
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Ajibade PA, Kolawole GA. Cobalt(III) Complexes of Some Antimalarial Drugs: Synthesis, Characterization, and in vitro Antiprotozoal Studies. ACTA ACUST UNITED AC 2010. [DOI: 10.1080/15533171003766691] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Peter A. Ajibade
- a Department of Chemistry , University of Fort Hare , Alice, South Africa
| | - Gabriel A. Kolawole
- b Department of Chemistry , University of Zululand , Kwadlangezwa, South Africa
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Ochieng CO, Ogweno Mid J, Okinda Owu P. Anti-Plasmodial and Larvicidal Effects of Surface Exudates ofGardenia ternifolia Aerial Parts. ACTA ACUST UNITED AC 2010. [DOI: 10.3923/rjpharm.2010.45.50] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Different behavior of artemisinin and tetraoxane in the oxidative degradation of phospholipid. Chem Phys Lipids 2009; 160:114-20. [DOI: 10.1016/j.chemphyslip.2009.04.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Revised: 04/27/2009] [Accepted: 04/28/2009] [Indexed: 11/20/2022]
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Mehlotra RK, Henry-Halldin CN, Zimmerman PA. Application of pharmacogenomics to malaria: a holistic approach for successful chemotherapy. Pharmacogenomics 2009; 10:435-49. [PMID: 19290792 DOI: 10.2217/14622416.10.3.435] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Drug resistance in malaria jeopardizes the most elementary objectives of malaria control--reducing suffering and eliminating mortality. An important, and so far the only known, mechanism of drug resistance appears to be polymorphisms in the malaria parasite genes. Efforts to circumvent antimalarial drug resistance now range from the use of combination therapies with existing agents to genomics-based studies directed toward discovering novel targets and agents. However, the potential contribution of host genetic/molecular factors, particularly those associated with antimalarial drug metabolism, remains largely unexplored. Our knowledge concerning the basic mechanisms involved in the pharmacokinetics of antimalarial drugs is fragmentary. In addition, the link between antimalarial drug pharmacokinetics and treatment outcomes is generally unclear. The purpose of this article is to provide general background information on antimalarial drug resistance and associated parasite genetic factors, and subsequently highlight the aforementioned unexplored and unclear areas, with a view to stimulate much needed further research.
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Affiliation(s)
- Rajeev K Mehlotra
- Center for Global Health and Diseases, Case Western Reserve University, School of Medicine, Wolstein Research Building #4204, 2103 Cornell Road, Cleveland, OH 44106-7286, USA.
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Kirby MJ, Milligan PJ, Conway DJ, Lindsay SW. Study protocol for a three-armed randomized controlled trial to assess whether house screening can reduce exposure to malaria vectors and reduce malaria transmission in The Gambia. Trials 2008; 9:33. [PMID: 18538004 PMCID: PMC2427015 DOI: 10.1186/1745-6215-9-33] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2008] [Accepted: 06/06/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mosquito-proofing homes was one of the principal methods of environmental management in the early 1900s. House screening provides protection against malaria by reducing exposure to malaria parasites and has the added benefit of protecting everyone sleeping in the house, avoiding issues of inequity within the household. The aim of this study is to determine whether house screening protects people against malaria in Africa. It is hoped that this study will mark the beginning of a series of trials assessing a range of environmental interventions for malaria control in Africa. DESIGN A 3-armed randomised-controlled trial will be conducted in and around Farafenni town in The Gambia, West Africa, to assess whether screening windows, doors and closing eaves or installing netting ceilings in local houses can substantially reduce malaria transmission and anaemia compared to homes with no screening. Eligible houses will be sorted and stratified by location and the number of children in each house, then randomly allocated to the interventions in blocks of 5 houses (2 with full screening, 2 with screened ceilings and 1 control house without screening). Risk of malaria transmission will be assessed in each house by routine collections of mosquitoes using light traps and an anaemia prevalence study in children at the end of the main transmission period. DISCUSSION Practical issues concerning intervention implementation, as well as the potential benefits and risks of the study, are discussed. TRIAL REGISTRATION ISRCTN51184253 - Screening-homes to prevent malaria.
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Affiliation(s)
- Matthew J Kirby
- Durham University, Science Laboratories, South Road, Durham, DH1 3LE, UK
- Medical Research Council Laboratories P.O. Box 273, Banjul, The Gambia
| | - Paul J Milligan
- London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - David J Conway
- Medical Research Council Laboratories P.O. Box 273, Banjul, The Gambia
- London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Steve W Lindsay
- Durham University, Science Laboratories, South Road, Durham, DH1 3LE, UK
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Weis R, Kaiser M, Brun R, Saf R, Seebacher W. Acyl derivatives of 5-amino-2-azabicyclo[3.2.2]nonanes. MONATSHEFTE FUR CHEMIE 2008. [DOI: 10.1007/s00706-007-0815-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Woodard CL, Keenan SM, Gerena L, Welsh WJ, Geyer JA, Waters NC. Evaluation of broad spectrum protein kinase inhibitors to probe the architecture of the malarial cyclin dependent protein kinase Pfmrk. Bioorg Med Chem Lett 2007; 17:4961-6. [PMID: 17588749 DOI: 10.1016/j.bmcl.2007.06.032] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2007] [Revised: 06/07/2007] [Accepted: 06/07/2007] [Indexed: 10/23/2022]
Abstract
We tested Pfmrk against several naphthalene and isoquinoline sulfonamides previously reported as protein kinase A (PKA) inhibitors. Pfmrk is a Cyclin Dependent protein Kinase (CDK) from Plasmodium falciparum, the causative parasite of the most lethal form of malaria. We find that the isoquinoline sulfonamides are potent inhibitors of Pfmrk and that substitution on the 5 position of the isoquinoline ring greatly influences the degree of potency. Molecular modeling studies suggest that the nitrogen atom in the isoquinoline ring plays a key role in ligand-receptor interactions. Structural analysis suggests that even subtle differences in amino acid composition within the active sites are responsible for conferring specificity of these inhibitors for Pfmrk over PKA.
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Affiliation(s)
- Cassandra L Woodard
- Division of Experimental Therapeutics, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA
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Polimorfismos del gen pfmdr1 en muestras clínicas de Plasmodium falciparum y su relación con la respuesta terapéutica a antipalúdicos y paludismo grave en Colombia. BIOMEDICA 2007. [DOI: 10.7705/biomedica.v27i2.216] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Woynarowski JM, Krugliak M, Ginsburg H. Pharmacogenomic analyses of targeting the AT-rich malaria parasite genome with AT-specific alkylating drugs. Mol Biochem Parasitol 2007; 154:70-81. [PMID: 17524501 DOI: 10.1016/j.molbiopara.2007.04.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2007] [Revised: 04/01/2007] [Accepted: 04/13/2007] [Indexed: 10/23/2022]
Abstract
UNLABELLED Human malaria parasites, including the most lethal Plasmodium falciparum, are increasingly resistant to existing antimalarial drugs. One remarkable opportunity to selectively target P. falciparum stems from the unique AT-richness of its genome (80% A/T, relative to 60% in human DNA). To rationally explore this opportunity, we used drugs (adozelesin and bizelesin) which distinctly target AT-rich minisatellites and an in silico approach for genome-wide analysis previously experimentally validated in human cells [Woynarowski JM, Trevino AV, Rodriguez KA, Hardies SC, Benham CJ. AT-rich islands in genomic DNA as a novel target for AT-specific DNA-reactive antitumor drugs. J Biol Chem 2001;276:40555-66]. Both drugs demonstrate a potent, rapid and irreversible inhibition of the cultured P. falciparum (50% inhibition at 110 and 10+/-2.3 pM, respectively). This antiparasital activity reflects most likely drug binding to specific super-AT-rich regions. Relative to the human genome, the P. falciparum genome shows 3.9- and 7-fold higher frequency of binding sites for adozelesin and bizelesin, respectively. The distribution of these sites is non-random with the most prominent clusters found in large unique minisatellites [median size 3.5 kbp of nearly pure A/T, with multiple converging repeats but no shared consensus other than (A/T)(n)]. Each of the fourteen P. falciparum chromosomes contains only one such "super-AT island" located within approximately 3-7.5 kbp of gene-free and nucleosome-free loci. Important functions of super-AT islands are suggested by their exceptional predicted potential to serve as matrix attachment regions (MARs) and a precise co-localization with the putative centromeres. CONCLUSION Super-AT islands, identified as unique domains in the P. falciparum genome with presumably crucial functions, offer therapeutically exploitable opportunity for new antimalarial strategies.
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Affiliation(s)
- Jan M Woynarowski
- Department of Radiation Oncology, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78245, USA.
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Abstract
BACKGROUND Mosquito larval control may prove to be an effective tool for incorporating into integrated vector management (IVM) strategies for reducing malaria transmission. Here the efficacy of microbial larvicides against Anopheles gambiae s.l. was tested in preparation for a large-scale larviciding programme in The Gambia. METHODS The impact of water-dispersible (WDG) and corn granule (CG) formulations of commercial Bacillus sphaericus strain 2362 (Bs; VectoLex) and Bacillus thuringiensis var.israelensis strain AM65-52 (Bti; VectoBac) on larval development were tested under laboratory and field conditions to (1) identify the susceptibility of local vectors, (2) evaluate the residual effect and re-treatment intervals, (3) test the effectiveness of the microbials under operational application conditions and (4) develop a method for large-scale application. RESULTS The major malaria vectors were highly susceptible to both microbials. The lethal concentration (LC) to kill 95% of third instar larvae of Anopheles gambiae s.s. after 24 hours was 0.023 mg/l (14.9 BsITU/l) for Bs WDG and 0.132 mg/l (396 ITU/l) for Bti WDG. In general Bs had little residual effect under field conditions even when the application rate was 200 times greater than the LC95. However, there was a residual effect up to 10 days in standardized field tests implemented during the dry season. Both microbials achieved 100% mortality of larvae 24-48 hours post-application but late instar larvae were detected 4 days after treatment. Pupae development was reduced by 94% (95% Confidence Interval = 90.8-97.5%) at weekly re-treatment intervals. Field tests showed that Bs had no residual activity against anopheline larvae. Both microbials provided complete protection when applied weekly. The basic training of personnel in identification of habitats, calibration of application equipment and active larviciding proved to be successful and achieved full coverage and control of mosquito larvae for three months under fully operational conditions. CONCLUSION Environmentally safe microbial larvicides can significantly reduce larval abundance in the natural habitats of The Gambia and could be a useful tool for inclusion in an IVM programme. The costs of the intervention in this setting could be reduced with formulations that provide a greater residual effect.
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Olliaro P. Drug resistance hampers our capacity to roll back malaria. Clin Infect Dis 2007; 41 Suppl 4:S247-57. [PMID: 16032560 DOI: 10.1086/430785] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Widespread drug resistance in parasites aggravates the burden of malaria. The extent of the problem is due mainly to the limited armamentarium of drugs used thus far to treat malaria and to policies and practices constrained by limited resources. All drugs in use are affected except, thus far, artemisinin derivatives. The scale and impact of resistance has been underestimated, leading to the continued use of failing drugs, which contributes to the rise in resistance and increased morbidity and mortality due to malaria. Pharmacological, epidemiological, and operational aspects factor the development and spread of resistance. Although the problem is complex, much can be done to reverse the course of events: adopt adequate tests to assess resistance, encourage and sustain development of new drugs, protect drugs against resistance through use of combinations, expand access to prompt and effective treatment, and promote evidence-based policies and sensible practices. The current situation favors the development of sensible strategies to restrain resistance.
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Affiliation(s)
- Piero Olliaro
- United Nations International Children's Emergency Fund/United Nations Development Programme/World Bank/World Health Organization Special Programme on Research and Training in Tropical Diseases, Geneva, Switzerland.
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Mzayek F, Deng H, Mather FJ, Wasilevich EC, Liu H, Hadi CM, Chansolme DH, Murphy HA, Melek BH, Tenaglia AN, Mushatt DM, Dreisbach AW, Lertora JJL, Krogstad DJ. Randomized dose-ranging controlled trial of AQ-13, a candidate antimalarial, and chloroquine in healthy volunteers. PLOS CLINICAL TRIALS 2007; 2:e6. [PMID: 17213921 PMCID: PMC1764434 DOI: 10.1371/journal.pctr.0020006] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2006] [Accepted: 11/03/2006] [Indexed: 11/18/2022]
Abstract
OBJECTIVES To determine: (1) the pharmacokinetics and safety of an investigational aminoquinoline active against multidrug-resistant malaria parasites (AQ-13), including its effects on the QT interval, and (2) whether it has pharmacokinetic and safety profiles similar to chloroquine (CQ) in humans. DESIGN Phase I double-blind, randomized controlled trials to compare AQ-13 and CQ in healthy volunteers. Randomizations were performed at each step after completion of the previous dose. SETTING Tulane-Louisiana State University-Charity Hospital General Clinical Research Center in New Orleans. PARTICIPANTS 126 healthy adults 21-45 years of age. INTERVENTIONS 10, 100, 300, 600, and 1,500 mg oral doses of CQ base in comparison with equivalent doses of AQ-13. OUTCOME MEASURES Clinical and laboratory adverse events (AEs), pharmacokinetic parameters, and QT prolongation. RESULTS No hematologic, hepatic, renal, or other organ toxicity was observed with AQ-13 or CQ at any dose tested. Headache, lightheadedness/dizziness, and gastrointestinal (GI) tract-related symptoms were the most common AEs. Although symptoms were more frequent with AQ-13, the numbers of volunteers who experienced symptoms with AQ-13 and CQ were similar (for AQ-13 and CQ, respectively: headache, 17/63 and 10/63, p = 0.2; lightheadedness/dizziness, 11/63 and 8/63, p = 0.6; GI symptoms, 14/63 and 13/63; p = 0.9). Both AQ-13 and CQ exhibited linear pharmacokinetics. However, AQ-13 was cleared more rapidly than CQ (respectively, median oral clearance 14.0-14.7 l/h versus 9.5-11.3 l/h; p < or = 0.03). QTc prolongation was greater with CQ than AQ-13 (CQ: mean increase of 28 ms; 95% confidence interval [CI], 18 to 38 ms, versus AQ-13: mean increase of 10 ms; 95% CI, 2 to 17 ms; p = 0.01). There were no arrhythmias or other cardiac AEs with either AQ-13 or CQ. CONCLUSIONS These studies revealed minimal differences in toxicity between AQ-13 and CQ, and similar linear pharmacokinetics.
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Affiliation(s)
- Fawaz Mzayek
- Center for Infectious Diseases, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Epidemiology, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Tropical Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Haiyan Deng
- Center for Infectious Diseases, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Tropical Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Frances J Mather
- Department of Biostatistics, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Elizabeth C Wasilevich
- Center for Infectious Diseases, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Epidemiology, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Tropical Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Huayin Liu
- Center for Infectious Diseases, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Tropical Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Christiane M Hadi
- Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - David H Chansolme
- Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Holly A Murphy
- Center for Infectious Diseases, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Tropical Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Bekir H Melek
- Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Alan N Tenaglia
- Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - David M Mushatt
- Center for Infectious Diseases, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Tropical Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Albert W Dreisbach
- Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Pharmacology, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Tulane–Louisiana State University–Charity Hospital General Clinical Research Center, New Orleans, Louisiana, United States of America
| | - Juan J. L Lertora
- Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Pharmacology, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Tulane–Louisiana State University–Charity Hospital General Clinical Research Center, New Orleans, Louisiana, United States of America
| | - Donald J Krogstad
- Center for Infectious Diseases, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Tropical Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Department of Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Tulane–Louisiana State University–Charity Hospital General Clinical Research Center, New Orleans, Louisiana, United States of America
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Fillinger U, Lindsay SW. Suppression of exposure to malaria vectors by an order of magnitude using microbial larvicides in rural Kenya. Trop Med Int Health 2007; 11:1629-42. [PMID: 17054742 DOI: 10.1111/j.1365-3156.2006.01733.x] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To determine the contribution larviciding could make to reduce the burden of malaria, by conducting a trial of microbial larvicides in a 4.5 km2 area in and around a large village in rural western Kenya. METHOD The abundance of immature and adult mosquitoes was monitored for 12 months under baseline conditions. Then microbial larval control was implemented for 28 months. After the intervention, the abundance of immature and adult mosquitoes was monitored for a further 12 months. RESULTS Of the 419 mosquito larval habitats identified, 336 (80%) originated from human activities. Application of Bacillus thuringiensis var. israelensis and Bacillus sphaericus larvicides reduced the proportion of aquatic habitats containing Anopheles larvae from 51% during non-intervention periods to 7% during the intervention. The occurrence of late instar Anopheles in habitats was reduced from 39% and 33% in pre-intervention and post-intervention periods to 0.6% during intervention. Overall, larviciding reduced Anopheles larval density by 95% and human exposure to bites from adults by 92%. The estimated cost of providing this protection to the human population in the study area was less than US$ 0.90/person/year. CONCLUSION Appropriately applied microbial larvicides can substantially and cost-effectively reduce human exposure to malaria in rural sub-Saharan Africa.
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Affiliation(s)
- Ulrike Fillinger
- School of Biological and Biomedical Sciences, Durham University, Durham, UK.
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Mbugi EV, Mutayoba BM, Malisa AL, Balthazary ST, Nyambo TB, Mshinda H. Drug resistance to sulphadoxine-pyrimethamine in Plasmodium falciparum malaria in Mlimba, Tanzania. Malar J 2006; 5:94. [PMID: 17076899 PMCID: PMC1636063 DOI: 10.1186/1475-2875-5-94] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2006] [Accepted: 10/31/2006] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Sulphadoxine-pyrimethamine (SP) has been and is currently used for treatment of uncomplicated Plasmodium falciparum malaria in many African countries. Nevertheless, the response of parasites to SP treatment has shown significant variation between individuals. METHODS The genes for dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) were used as markers, to investigate parasite resistance to SP in 141 children aged less than 5 years. Parasite DNA was extracted by Chelex method from blood samples collected and preserved on filter papers. Subsequently, polymerase chain reaction (PCR) and restriction fragment length polymorphism (PCR-RFLP) were applied to detect the SP resistance-associated point mutations on dhfr and dhps. Commonly reported point mutations at codons 51, 59, 108 and 164 in the dhfr and codons 437, 540 and 581 in the dhps domains were examined. RESULTS Children infected with parasites harbouring a range of single to quintuple dhfr/dhps mutations were erratically cured with SP. However, the quintuple dhfr/dhps mutant genotypes were mostly associated with treatment failures. High proportion of SP resistance-associated point mutations was detected in this study but the adequate clinical response (89.4%) observed clinically at day 14 of follow up reflects the role of semi-immunity protection and parasite clearance in the population. CONCLUSION In monitoring drug resistance to SP, concurrent studies on possible confounding factors pertaining to development of resistance in falciparum malaria should be considered. The SP resistance potential detected in this study, cautions on its useful therapeutic life as an interim first-line drug against malaria in Tanzania and other malaria-endemic countries.
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Affiliation(s)
- Erasto V Mbugi
- Department of Veterinary Physiology, Biochemistry, Pharmacology and Toxicology, Faculty of Veterinary Medicine, Sokoine University of Agriculture (SUA), P.O. Box 3017, Morogoro, Tanzania
- Department of Biochemistry, School of Medicine, Muhimbili University College of Health Sciences (MUCHS), P.O. Box 65001, Dar es Salaam, Tanzania
- Cell Biology and immunology group, Department of Animal Sciences, Wageningen University, P.O. Box 338, 6700 AH Wageningen, The Netherlands
| | - Benezeth M Mutayoba
- Department of Veterinary Physiology, Biochemistry, Pharmacology and Toxicology, Faculty of Veterinary Medicine, Sokoine University of Agriculture (SUA), P.O. Box 3017, Morogoro, Tanzania
| | - Allen L Malisa
- Department of Biological Sciences, Faculty of Science, Sokoine University of Agriculture, P.O. Box 3038, Morogoro, Tanzania
| | - Sakurani T Balthazary
- Department of Veterinary Physiology, Biochemistry, Pharmacology and Toxicology, Faculty of Veterinary Medicine, Sokoine University of Agriculture (SUA), P.O. Box 3017, Morogoro, Tanzania
| | - Thomas B Nyambo
- Department of Biochemistry, School of Medicine, Muhimbili University College of Health Sciences (MUCHS), P.O. Box 65001, Dar es Salaam, Tanzania
| | - Hassan Mshinda
- Ifakara Health Research and Development Centre (IHRDC), Off Mlabani Road, P.O. Box 53, Ifakara, Kilombero District, Morogoro, Tanzania
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Argotte-Ramos R, Ramírez-Avila G, Rodríguez-Gutiérrez MDC, Ovilla-Muñoz M, Lanz-Mendoza H, Rodríguez MH, Gonzalez-Cortazar M, Alvarez L. Antimalarial 4-phenylcoumarins from the stem bark of Hintonia latiflora. JOURNAL OF NATURAL PRODUCTS 2006; 69:1442-4. [PMID: 17067158 DOI: 10.1021/np060233p] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The EtOAc extract of the stem bark of Hintonia latiflora showed the suppression of total parasitemia and the chemosuppression of schizont numbers, when tested in vivo against Plasmodium berghei infection in mice. Bioassay-directed fractionation of the EtOAc extract, using the in vitro 16 h and the in vivo 4-day suppression tests on P. berghei schizont numbers, led to the isolation of the new compound 5-O-beta-D-glucopyranosyl-7,4'-dimethoxy-3'-hydroxy-4-phenylcoumarin (1), along with the known 5-O-beta-D-glucopyranosyl-7-methoxy-3',4'-dihydroxy-4-phenylcoumarin (2). The structure of compound 1 was established on the basis of spectroscopic data interpretation. Compounds 1 and 2 suppressed the development of P. berghei schizonts in vitro with IC50 values of 24.7 and 25.9 microM, respectively. Compound 2 suppressed the development of schizonts at the dose of 40 mg/kg by 70.8% in the in vivo assay.
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Affiliation(s)
- Rocío Argotte-Ramos
- Instituto Nacional de Salud Pública, Centro de Investigación sobre Enfermedades Infecciosas, Enfermedades Transmitidas por Vector, Departamento de Entomología Médica, Avenida Universidad 655, Cuernavaca, Morelos, México
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Hydrazones and new Oximes of 4-Aminobicyclo[2.2.2]octanones and their Antiprotozoal Activities. MONATSHEFTE FUR CHEMIE 2006. [DOI: 10.1007/s00706-006-0535-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Chen Y, Jirage D, Caridha D, Kathcart AK, Cortes EA, Dennull RA, Geyer JA, Prigge ST, Waters NC. Identification of an effector protein and gain-of-function mutants that activate Pfmrk, a malarial cyclin-dependent protein kinase. Mol Biochem Parasitol 2006; 149:48-57. [PMID: 16737745 DOI: 10.1016/j.molbiopara.2006.04.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2006] [Revised: 04/06/2006] [Accepted: 04/18/2006] [Indexed: 11/21/2022]
Abstract
Cyclin-dependent protein kinases (CDKs) are key regulators of cell cycle control. In humans, CDK7 performs dual roles as the CDK activating kinase (CAK) responsible for regulating numerous CDKs and as the RNA polymerase II carboxyl-terminal domain (CTD) kinase involved in the regulation of transcription. Binding of an effector protein, human MAT1, stimulates CDK7 kinase activity and influences substrate specificity. In Plasmodium falciparum, CDKs and their roles in regulating growth and development are poorly understood. In this study, we characterized the regulatory mechanisms of Pfmrk, a putative homolog of human CDK7. We identified an effector, PfMAT1, which stimulates Pfmrk kinase activity in a cyclin-dependent manner. The addition of PfMAT1 stimulated RNA polymerase II CTD phosphorylation and had no effect on the inability of Pfmrk to phosphorylate PfPK5, a putative CDK1 homolog, which suggests that Pfmrk may be a CTD kinase rather than a CAK. In an attempt to abrogate the requirement for PfMAT1 stimulation, we mutated amino acids within the active site of Pfmrk. We found that two independent mutants, S138K and F143L, yielded a 4-10-fold increase in Pfmrk activity. Significant kinase activity of these mutants was observed in the absence of either cyclin or PfMAT1. Finally, we observed autophosphorylation of Pfmrk that is unaffected by the addition of either cyclin or PfMAT1.
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Affiliation(s)
- Yueqin Chen
- Department of Parasitology, Division of Experimental Therapeutics, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
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Bukirwa H, Yeka A, Kamya MR, Talisuna A, Banek K, Bakyaita N, Rwakimari JB, Rosenthal PJ, Wabwire-Mangen F, Dorsey G, Staedke SG. Artemisinin combination therapies for treatment of uncomplicated malaria in Uganda. PLOS CLINICAL TRIALS 2006; 1:e7. [PMID: 16871329 PMCID: PMC1488893 DOI: 10.1371/journal.pctr.0010007] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2006] [Accepted: 04/07/2006] [Indexed: 12/03/2022]
Abstract
OBJECTIVES To compare the efficacy and safety of artemisinin combination therapies for the treatment of uncomplicated falciparum malaria in Uganda. DESIGN Randomized single-blind controlled trial. SETTING Tororo, Uganda, an area of high-level malaria transmission. PARTICIPANTS Children aged one to ten years with confirmed uncomplicated P. falciparum malaria. INTERVENTIONS Amodiaquine + artesunate or artemether-lumefantrine. OUTCOME MEASURES Risks of recurrent symptomatic malaria and recurrent parasitemia at 28 days, unadjusted and adjusted by genotyping to distinguish recrudescences and new infections. RESULTS Of 408 participants enrolled, 403 with unadjusted efficacy outcomes were included in the per-protocol analysis. Both treatment regimens were highly efficacious; no recrudescences occurred in patients treated with amodiaquine + artesunate, and only two occurred in those treated with artemether-lumefantrine. However, recurrent malaria due to new infections was common. The unadjusted risk of recurrent symptomatic malaria was significantly lower for participants treated with artemether-lumefantrine than for those treated with amodiaquine + artesunate (27% versus 42%, risk difference 15%, 95% CI 5.9%-24.2%). Similar results were seen for the risk of recurrent parasitemia (51% artemether-lumefantrine versus 66% amodiaquine + artesunate, risk difference 16%, 95% CI 6.2%-25.2%). Amodiaquine + artesunate and artemether-lumefantrine were both well-tolerated. Serious adverse events were uncommon with both regimens. CONCLUSIONS Amodiaquine + artesunate and artemether-lumefantrine were both highly efficacious for treatment of uncomplicated malaria. However, in this holoendemic area, despite the excellent performance of both regimens in terms of efficacy, many patients experienced recurrent parasitemia due to new infections. Artemether-lumefantrine was superior to amodiaquine + artesunate for prevention of new infections. To maximize the benefit of artemisinin combination therapy in Africa, treatment should be integrated with strategies to prevent malaria transmission. The impact of frequent repeated therapy on the efficacy, safety, and cost-effectiveness of new artemisinin regimens should be further investigated.
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Affiliation(s)
| | - Adoke Yeka
- Uganda Malaria Surveillance Project, Kampala, Uganda
| | | | | | - Kristin Banek
- Uganda Malaria Surveillance Project, Kampala, Uganda
| | | | | | - Philip J Rosenthal
- Department of Medicine, San Francisco General Hospital, University of California, San Francisco, United States of America
| | | | - Grant Dorsey
- Department of Medicine, San Francisco General Hospital, University of California, San Francisco, United States of America
| | - Sarah G Staedke
- Department of Medicine, San Francisco General Hospital, University of California, San Francisco, United States of America
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Weis R, Schlapper C, Brun R, Kaiser M, Seebacher W. Antiplasmodial and antitrypanosomal activity of new esters and ethers of 4-dialkylaminobicyclo[2.2.2]octan-2-ols. Eur J Pharm Sci 2006; 28:361-8. [PMID: 16713699 DOI: 10.1016/j.ejps.2006.04.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2005] [Revised: 02/09/2006] [Accepted: 04/02/2006] [Indexed: 11/17/2022]
Abstract
Only three drugs are available for the treatment of East African trypanosomiasis. Patients suffer from painful application, severe side effects and increasing resistance against these drugs. Malaria tropica kills more than 2 million people every year mainly due to growing drug resistance. 4-Dialkylaminobicyclo[2.2.2]octan-2-ols and some of their esters have shown activity against both the causative organisms, Trypanosoma brucei rhodesiense and Plasmodium falciparum. Ethers and new esters with markedly higher lipophilicity were prepared in three-step procedures from acyclic synthons. The new compounds were screened for their antiprotozoal activities against T. b. rhodesiense (STIB 900) and P. falciparum K1 (resistant to chloroquine and pyrimethamine), and for their cytotoxicity with L-6 cells by means of in vitro microplate assays. The results were compared to those of the parent compounds indicating that higher lipophilicity increases the antiprotozoal activities. The pivalate 10a showed the highest antitrypanosomal activity. The 4-chlorobenzoate 9b exhibited good antiplasmodial activity and low cytotoxicity. The most active antiplasmodial agent was the benzhydryl ether 13c which was nearly as active as chloroquine against sensitive strains.
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Affiliation(s)
- Robert Weis
- Institute of Pharmaceutical Sciences, Pharmaceutical Chemistry, Karl-Franzens-University, Universitätsplatz 1, A-8010 Graz, Austria.
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Haemers T, Wiesner J, Van Poecke S, Goeman J, Henschker D, Beck E, Jomaa H, Van Calenbergh S. Synthesis of α-substituted fosmidomycin analogues as highly potent Plasmodium falciparum growth inhibitors. Bioorg Med Chem Lett 2006; 16:1888-91. [PMID: 16439126 DOI: 10.1016/j.bmcl.2005.12.082] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2005] [Revised: 12/23/2005] [Accepted: 12/28/2005] [Indexed: 11/29/2022]
Abstract
In view of the promising antimalarial activity of fosmidomycin or its N-acetyl homologue FR900098, the objective of this work was to investigate the influence of aromatic substituents in the alpha-position of the phosphonate moiety. The envisaged analogues were prepared using a linear route involving a 3-aryl-3-phosphoryl propanal intermediate. The activities of all compounds were evaluated on Eschericia coli 1-deoxy-d-xylulose 5-phosphate reductoisomerase and against two Plasmodium falciparum strains. Compared with fosmidomycin, several analogues displayed enhanced activity towards the P. falciparum strains. Compound 1e with a 3,4-dichlorophenyl substitution in the alpha-position of fosmidomycin emerged as the most potent analogue of this series. It is approximately three times more potent in inhibiting the growth of P. falciparum than FR900098, the most potent representative of this class reported so far.
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Affiliation(s)
- Timothy Haemers
- Laboratory for Medicinal Chemistry (FFW), Ghent University, Harelbekestraat 72, 9000 Gent, Belgium
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44
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Bray PG, Ward SA, O'Neill PM. Quinolines and artemisinin: chemistry, biology and history. Curr Top Microbiol Immunol 2005; 295:3-38. [PMID: 16265885 DOI: 10.1007/3-540-29088-5_1] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Plasmodium falciparum is the most important parasitic pathogen in humans, causing hundreds of millions of malaria infections and millions of deaths each year. At present there is no effective malaria vaccine and malaria therapy is totally reliant on the use of drugs. New drugs are urgently needed because of the rapid evolution and spread of parasite resistance to the current therapies. Drug resistance is one of the major factors contributing to the resurgence of malaria, especially resistance to the most affordable drugs such as chloroquine. We need to fully understand the antimalarial mode of action of the existing drugs and the way that the parasite becomes resistant to them in order to design and develop the new therapies that are so urgently needed. In respect of the quinolines and artemisinins, great progress has been made recently in studying the mechanisms of drug action and drug resistance in malaria parasites. Here we summarize from a historical, biological and chemical, perspective the exciting new advances that have been made in the study of these important antimalarial drugs.
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Affiliation(s)
- P G Bray
- Division of Molecular and Biochemical Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK.
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Hyde JE. Drug-resistant malaria. Trends Parasitol 2005; 21:494-8. [PMID: 16140578 PMCID: PMC2722032 DOI: 10.1016/j.pt.2005.08.020] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2005] [Revised: 08/08/2005] [Accepted: 08/18/2005] [Indexed: 11/26/2022]
Abstract
In the past 21 years, a modest increase in the range of antimalarial drugs approved for clinical use has been complemented by a more impressive expansion in the analysis and understanding of the molecular mechanisms underlying resistance to these agents. Such resistance is a major factor in the increasing difficulty in controlling malaria, and important developments during this period are recounted here.
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Affiliation(s)
- John E Hyde
- Faculty of Life Sciences, University of Manchester, Jackson's Mill, PO Box 88, Manchester M60 1QD, UK.
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Abstract
As in centuries past, the main weapon against human malaria infections continues to be intervention with drugs, despite the widespread and increasing frequency of parasite populations that are resistant to one or more of the available compounds. This is a particular problem with the lethal species of parasite, Plasmodium falciparum, which claims some two million lives per year as well as causing enormous social and economic problems. Amongst the antimalarial drugs currently in clinical use, the antifolates have the best defined molecular targets, namely the enzymes dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS), which function in the folate metabolic pathway. The products of this pathway, reduced folate cofactors, are essential for DNA synthesis and the metabolism of certain amino acids. Moreover, their formation and interconversions involve a number of other enzymes that have not as yet been exploited as drug targets. Antifolates are of major importance as they currently represent the only inexpensive regime for combating chloroquine-resistant malaria, and are now first-line drugs in a number of African countries. Aspects of our understanding of this pathway and antifolate drug resistance are reviewed here, with a particular emphasis on approaches to analysing the details of, and balance between, folate biosynthesis by the parasite and salvage of pre-formed folate from exogenous sources.
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Affiliation(s)
- John E Hyde
- Faculty of life Sciences, University of Manchester, P.O. Box 88, Manchester M60 1QD, UK.
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Baldwin J, Michnoff CH, Malmquist NA, White J, Roth MG, Rathod PK, Phillips MA. High-throughput screening for potent and selective inhibitors of Plasmodium falciparum dihydroorotate dehydrogenase. J Biol Chem 2005; 280:21847-53. [PMID: 15795226 DOI: 10.1074/jbc.m501100200] [Citation(s) in RCA: 137] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Plasmodium falciparum is the causative agent of the most serious and fatal malarial infections, and it has developed resistance to commonly employed chemotherapeutics. The de novo pyrimidine biosynthesis enzymes offer potential as targets for drug design, because, unlike the host, the parasite does not have pyrimidine salvage pathways. Dihydroorotate dehydrogenase (DHODH) is a flavin-dependent mitochondrial enzyme that catalyzes the fourth reaction in this essential pathway. Coenzyme Q (CoQ) is utilized as the oxidant. Potent and species-selective inhibitors of malarial DHODH were identified by high-throughput screening of a chemical library, which contained 220,000 drug-like molecules. These novel inhibitors represent a diverse range of chemical scaffolds, including a series of halogenated phenyl benzamide/naphthamides and urea-based compounds containing napthyl or quinolinyl substituents. Inhibitors in these classes with IC(50) values below 600 nm were purified by high pressure liquid chromatography, characterized by mass spectroscopy, and subjected to kinetic analysis against the parasite and human enzymes. The most active compound is a competitive inhibitor of CoQ with an IC(50) against malarial DHODH of 16 nm, and it is 12,500-fold less active against the human enzyme. Site-directed mutagenesis of residues in the CoQ-binding site significantly reduced inhibitor potency. The structural basis for the species selective enzyme inhibition is explained by the variable amino acid sequence in this binding site, making DHODH a particularly strong candidate for the development of new anti-malarial compounds.
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Affiliation(s)
- Jeffrey Baldwin
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9041, USA
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Ocheskey JA, Harpstrite SE, Oksman A, Goldberg DE, Sharma V. Metalloantimalarials: synthesis and characterization of a novel agent possessing activity against Plasmodium falciparum. Chem Commun (Camb) 2005:1622-4. [PMID: 15770280 DOI: 10.1039/b415771k] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis, characterization, and antimalarial potency of an amine-phenol complex of gallium(III), [{1,12-bis(2-hydroxy-3-methoxy-5-(quinolin-3-yl)-benzyl)-1,5,8,12-tetraazadodecane}-gallium(III)]+, [Ga-3-M-5-Quadd]+ (7) is described; a novel agent that targets Plasmodium falciparum strains.
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Affiliation(s)
- Joseph A Ocheskey
- Mallinckrodt Institute of Radiology, Washington University Medical School, St. Louis, MO, USA
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Bhattacharjee AK, Geyer JA, Woodard CL, Kathcart AK, Nichols DA, Prigge ST, Li Z, Mott BT, Waters NC. A three-dimensional in silico pharmacophore model for inhibition of Plasmodium falciparum cyclin-dependent kinases and discovery of different classes of novel Pfmrk specific inhibitors. J Med Chem 2004; 47:5418-26. [PMID: 15481979 DOI: 10.1021/jm040108f] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The cell division cycle is regulated by a family of cyclin-dependent protein kinases (CDKs) that are functionally conserved among many eukaryotic species. The characterization of plasmodial CDKs has identified them as a leading antimalarial drug target in our laboratory. We have developed a three-dimensional QSAR pharmacophore model for inhibition of a Plasmodium falciparum CDK, known as Pfmrk, from a set of fifteen structurally diverse kinase inhibitors with a wide range of activity. The model was found to contain two hydrogen bond acceptor functions and two hydrophobic sites including one aromatic-ring hydrophobic site. Although the model was not developed from X-ray structural analysis of the known CDK2 structure, it is consistent with the structure-functional requirements for binding of the CDK inhibitors in the ATP binding pocket. Using the model as a template, a search of the in-house three-dimensional multiconformer database resulted in the discovery of sixteen potent Pfmrk inhibitors. The predicted inhibitory activities of some of these Pfmrk inhibitors from the molecular model agree exceptionally well with the experimental inhibitory values from the in vitro CDK assay.
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Affiliation(s)
- Apurba K Bhattacharjee
- Division of Experimental Therapeutics, Walter Reed Army Institute of Research, Silver Spring, Maryland 20910-7500, USA.
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Abstract
PURPOSE OF REVIEW Malaria remains a major cause of death in much of the world. The routine treatment of malaria is currently threatened by rising rates of drug resistance. Moreover, mortality among children with severe and complicated malaria remains unacceptably high. Here we review trends in antimalarial drug resistance and report on the progress of newer drugs and drug combinations. We then review some recent literature regarding the pathological processes involved in the aetiology of severe malaria that may lead to improvements in the management of children with severe disease. RECENT FINDINGS Resistance to first line therapies, including chloroquine and sulphadoxine/pyramethamine, continues to rise in many parts of the world. The availability of newer and more effective drugs and fixed drug combinations is hampered by financial and political considerations. Nevertheless, a number of promising drugs and supportive treatments for both mild and severe malaria are at various stages of development. SUMMARY A range of newer drugs and fixed drug combinations are now available that are safe and effective. However, these drugs remain expensive and their introduction will require political and financial support at every level. Considerable work is still required to achieve a better understanding of the processes involved in the pathogenesis of severe and complicated malaria. Only then will it be possible to develop new and appropriate therapies that will be widely applicable.
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Affiliation(s)
- Kathryn Maitland
- The Centre for Geographic Medicine Research, Coast, KEMRI, Kilifi, Kenya.
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