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Rocha E Silva LF, Ramalhete C, Nogueira KL, Mulhovo S, Ferreira MJU, Pohlit AM. In vivo evaluation of isolated triterpenes and semi-synthetic derivatives as antimalarial agents. Eur J Med Chem 2015; 102:398-402. [PMID: 26301556 DOI: 10.1016/j.ejmech.2015.08.022] [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: 05/23/2015] [Revised: 08/02/2015] [Accepted: 08/09/2015] [Indexed: 12/12/2022]
Abstract
The triterpenes balsaminoside B (1) and karavilagenin C (2) were isolated from the African medicinal plant Momordica balsamina L. Karavoates B (3) and D (4) were synthesized by diacylation of 2 with acetic and propionic anhydrides, respectively. In previous work, derivatives 3 and 4 exhibited submicromolar median inhibitory concentrations (IC50) in vitro against Plasmodium falciparum Welch (human malaria parasite) strains 20 to 25 times lower than those of natural product 2. The main objective of the present study was to explore structure-in vivo antimalarial activity relationships (SAR) for compounds 1-4 in Plasmodium berghei Vincke and Lips NK65-infected mice in the 4 day suppressive test. Semi-synthetic derivatives 3 and 4 exhibited greater in vivo antimalarial activity than isolates 1 and 2. Orally and subcutaneously administered karavoate B exhibited the greatest in vivo antimalarial activity (55.2-58.1% maximal suppression of parasitemia at doses of 50 mg kg(-1) day(-1)). Diacylation of natural isolate 2 with short chain carboxylic acid moieties yielded derivatives with enhanced maximal in vivo parasitemia suppression for both routes of administration. Maximal in vivo parasite suppression by diacetyl derivative 3 was roughly double that of natural precursor 2.
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Affiliation(s)
- Luiz Francisco Rocha E Silva
- Amazon Active Principles Laboratory (LAPAAM), Department of Technology and Innovation (COTI), National Institute for Amazon Research (INPA), Avenida André Araújo 2936, Bairro Petrópolis, CEP 69067-375, Manaus, Amazonas, Brazil.
| | - Cátia Ramalhete
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, University of Lisbon, Av. Prof. Gama Pinto, 1649-003, Lisbon, Portugal.
| | - Karla Lagos Nogueira
- Amazon Active Principles Laboratory (LAPAAM), Department of Technology and Innovation (COTI), National Institute for Amazon Research (INPA), Avenida André Araújo 2936, Bairro Petrópolis, CEP 69067-375, Manaus, Amazonas, Brazil.
| | - Silva Mulhovo
- Mozambican and Ethnoscience Study Center (CEMEC), Faculty of Mathematics and Natural Sciences, Pedagogic University, Lhanguene Campus, Av. de Moçambique, 21402161, Maputo, Mozambique.
| | - Maria-José U Ferreira
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, University of Lisbon, Av. Prof. Gama Pinto, 1649-003, Lisbon, Portugal.
| | - Adrian Martin Pohlit
- Amazon Active Principles Laboratory (LAPAAM), Department of Technology and Innovation (COTI), National Institute for Amazon Research (INPA), Avenida André Araújo 2936, Bairro Petrópolis, CEP 69067-375, Manaus, Amazonas, Brazil.
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Badugu SB, Nabi SA, Vaidyam P, Laskar S, Bhattacharyya S, Bhattacharyya MK. Identification of Plasmodium falciparum DNA Repair Protein Mre11 with an Evolutionarily Conserved Nuclease Function. PLoS One 2015; 10:e0125358. [PMID: 25938776 PMCID: PMC4418825 DOI: 10.1371/journal.pone.0125358] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 03/12/2015] [Indexed: 11/25/2022] Open
Abstract
The eukaryotic Meiotic Recombination protein 11 (Mre11) plays pivotal roles in the DNA damage response (DDR). Specifically, Mre11 senses and signals DNA double strand breaks (DSB) and facilitates their repair through effector proteins belonging to either homologous recombination (HR) or non-homologous end joining (NHEJ) repair mechanisms. In the human malaria parasite Plasmodium falciparum, HR and alternative-NHEJ have been identified; however, little is known about the upstream factors involved in the DDR of this organism. In this report, we identify a putative ortholog of Mre11 in P. falciparum (PfalMre11) that shares 22% sequence similarity to human Mre11. Homology modeling reveals striking structural resemblance of the predicted PfalMre11 nuclease domain to the nuclease domain of Saccharomyces cerevisiae Mre11 (ScMre11). Complementation analyses reveal functional conservation of PfalMre11 nuclease activity as demonstrated by the ability of the PfalMre11 nuclease domain, in conjunction with the C-terminal domain of ScMre11, to functionally complement an mre11 deficient yeast strain. Functional complementation was virtually abrogated by an amino acid substitution in the PfalMre11 nuclease domain (D398N). PfalMre11 is abundant in the mitotically active trophozoite and schizont stages of P. falciparum and is up-regulated in response to DNA damage, suggesting a role in the DDR. PfalMre11 exhibits physical interaction with PfalRad50. In addition, yeast 2-hybrid studies show that PfalMre11 interacts with ScRad50 and ScXrs2, two important components of the well characterized Mre11-Rad50-Xrs2 complex which is involved in DDR signaling and repair in S. cerevisiae, further supporting a role for PfalMre11 in the DDR. Taken together, these findings provide evidence that PfalMre11 is an evolutionarily conserved component of the DDR in Plasmodium.
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Affiliation(s)
- Sugith Babu Badugu
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Shaik Abdul Nabi
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Pratap Vaidyam
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Shyamasree Laskar
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Sunanda Bhattacharyya
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad, India
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Baird K. Origins and implications of neglect of G6PD deficiency and primaquine toxicity in Plasmodium vivax malaria. Pathog Glob Health 2015; 109:93-106. [PMID: 25943156 PMCID: PMC4455359 DOI: 10.1179/2047773215y.0000000016] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Most of the tens of millions of clinical attacks caused by Plasmodium vivax each year likely originate from dormant liver forms called hypnozoites. We do not systematically attack that reservoir because the only drug available, primaquine, is poorly suited to doing so. Primaquine was licenced for anti-relapse therapy in 1952 and became available despite threatening patients having an inborn deficiency of glucose-6-phosphate dehydrogenase (G6PD) with acute haemolytic anaemia. The standard method for screening G6PD deficiency, the fluorescent spot test, has proved impractical where most malaria patients live. The blind administration of daily primaquine is dangerous, but so too are the relapses invited by withholding treatment. Absent G6PD screening, providers must choose between risking harm by the parasite or its treatment. How did this dilemma escape redress in science, clinical medicine and public health? This review offers critical historic reflection on the neglect of this serious problem in the chemotherapy of P. vivax.
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Huang F, Takala-Harrison S, Jacob CG, Liu H, Sun X, Yang H, Nyunt MM, Adams M, Zhou S, Xia Z, Ringwald P, Bustos MD, Tang L, Plowe CV. A Single Mutation in K13 Predominates in Southern China and Is Associated With Delayed Clearance of Plasmodium falciparum Following Artemisinin Treatment. J Infect Dis 2015; 212:1629-35. [PMID: 25910630 DOI: 10.1093/infdis/jiv249] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 04/16/2015] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Artemisinin resistance in Plasmodium falciparum has emerged in Southeast Asia and poses a threat to malaria control and elimination. Mutations in a P. falciparum gene encoding a kelch protein on chromosome 13 have been associated with delayed parasite clearance following artemisinin treatment elsewhere in the region, but not yet in China. METHODS Therapeutic efficacy studies of artesunate and dihydroartemisinin-piperaquine were conducted from 2009 to 2012 in the Yunnan Province of China near the border with Myanmar. K13 mutations were genotyped by capillary sequencing of DNA extracted from dried blood spots collected in these clinical trials and in routine surveillance. Associations between K13 mutations and delayed parasite clearance were tested using regression models. RESULTS Parasite clearance half-lives were prolonged after artemisinin treatment, with 44% of infections having half-lives >5 hours (n = 109). Fourteen mutations in K13 were observed, with an overall prevalence of 47.7% (n = 329). A single mutation, F446I, predominated, with a prevalence of 36.5%. Infections with F446I were significantly associated with parasitemia on day 3 following artemisinin treatment and with longer clearance half-lives. CONCLUSIONS Plasmodium falciparum infections in southern China displayed markedly delayed clearance following artemisinin treatment. F446I was the predominant K13 mutation and was associated with delayed parasite clearance.
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Affiliation(s)
- Fang Huang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, World Health Organization Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, PR China Center for Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore
| | - Shannon Takala-Harrison
- Center for Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore
| | - Christopher G Jacob
- Center for Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore
| | - Hui Liu
- Yunnan Institute of Parasitic Diseases, Puer, PR China
| | - Xiaodong Sun
- Yunnan Institute of Parasitic Diseases, Puer, PR China
| | - Henglin Yang
- Yunnan Institute of Parasitic Diseases, Puer, PR China
| | - Myaing M Nyunt
- Center for Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore
| | - Matthew Adams
- Center for Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore
| | - Shuisen Zhou
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, World Health Organization Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, PR China
| | - Zhigui Xia
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, World Health Organization Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, PR China
| | - Pascal Ringwald
- Drug Resistance and Containment Unit, Global Malaria Programme, World Health Organization, Geneva, Switzerland
| | | | - Linhua Tang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, World Health Organization Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, PR China
| | - Christopher V Plowe
- Center for Malaria Research, Institute for Global Health, University of Maryland School of Medicine, Baltimore
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Abstract
Malaria, as a key disease of poverty, was singled out for special attention in the Millennium Project of 2000. Recent data suggest that malaria incidence and mortality are now declining all over the world. While these figures are cause for celebration, they must be interpreted carefully and with caution, particularly in relation to Africa. There are daunting challenges ahead for those working to achieve malaria eradication, not least of which is the poor quality of the data on which the work is based. In the absence of an affordable and fully effective vaccine, international funding for malaria control needs to be escalated still further. The money is essential to pay for universal access to a set of simple and proven interventions which would save the lives of millions of children over the next 15 years.
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Affiliation(s)
- Stephen Owens
- Child Health Business Unit, Northumbria Healthcare NHS Foundation Trust, North Shields, UK Institute of Health and Society, Newcastle University, Newcastle upon Tyne, UK
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Koleala T, Karl S, Laman M, Moore BR, Benjamin J, Barnadas C, Robinson LJ, Kattenberg JH, Javati S, Wong RPM, Rosanas-Urgell A, Betuela I, Siba PM, Mueller I, Davis TME. Temporal changes in Plasmodium falciparum anti-malarial drug sensitivity in vitro and resistance-associated genetic mutations in isolates from Papua New Guinea. Malar J 2015; 14:37. [PMID: 25626445 PMCID: PMC4335551 DOI: 10.1186/s12936-015-0560-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 01/13/2015] [Indexed: 01/19/2023] Open
Abstract
Background In northern Papua New Guinea (PNG), most Plasmodium falciparum isolates proved resistant to chloroquine (CQ) in vitro between 2005 and 2007, and there was near-fixation of pfcrt K76T, pfdhfr C59R/S108N and pfmdr1 N86Y. To determine whether the subsequent introduction of artemisinin combination therapy (ACT) and reduced CQ-sulphadoxine-pyrimethamine pressure had attenuated parasite drug susceptibility and resistance-associated mutations, these parameters were re-assessed between 2011 and 2013. Methods A validated fluorescence-based assay was used to assess growth inhibition of 52 P. falciparum isolates from children in a clinical trial in Madang Province. Responses to CQ, lumefantrine, piperaquine, naphthoquine, pyronaridine, artesunate, dihydroartemisinin, artemether were assessed. Molecular resistance markers were detected using a multiplex PCR ligase detection reaction fluorescent microsphere assay. Results CQ resistance (in vitro concentration required for 50% parasite growth inhibition (IC50) >100 nM) was present in 19% of isolates. All piperaquine and naphthoquine IC50s were <100 nM and those for lumefantrine, pyronaridine and the artemisinin derivatives were in low nM ranges. Factor analysis of IC50s showed three groupings (lumefantrine; CQ, piperaquine, naphthoquine; pyronaridine, dihydroartemisinin, artemether, artesunate). Most isolates (96%) were monoclonal pfcrt K76T (SVMNT) mutants and most (86%) contained pfmdr1 N86Y (YYSND). No wild-type pfdhfr was found but most isolates contained wild-type (SAKAA) pfdhps. Compared with 2005–2007, the geometric mean (95% CI) CQ IC50 was lower (87 (71–107) vs 167 (141–197) nM) and there had been no change in the prevalence of pfcrt K76T or pfmdr1 mutations. There were fewer isolates of the pfdhps (SAKAA) wild-type (60 vs 100%) and pfdhfr mutations persisted. Conclusions Reflecting less drug pressure, in vitro CQ sensitivity appears to be improving in Madang Province despite continued near-fixation of pfcrt K76T and pfmdr1 mutations. Temporal changes in IC50s for other anti-malarial drugs were inconsistent but susceptibility was preserved. Retention or increases in pfdhfr and pfdhps mutations reflect continued use of sulphadoxine-pyrimethamine in the study area including through paediatric intermittent preventive treatment. The susceptibility of local isolates to lumefantrine may be unrelated to those of other ACT partner drugs. Trial registration Australian New Zealand Clinical Trials Registry ACTRN12610000913077.
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Affiliation(s)
- Tamarah Koleala
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea.
| | - Stephan Karl
- School of Medicine and Pharmacology, University of Western Australia, Fremantle Hospital, PO Box 480, Fremantle, 6959, WA, Australia. .,Infection and Immunity Division, Walter and Eliza Hall Institute, Parkville, VIC, Australia. .,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia.
| | - Moses Laman
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea. .,School of Medicine and Pharmacology, University of Western Australia, Fremantle Hospital, PO Box 480, Fremantle, 6959, WA, Australia.
| | - Brioni R Moore
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea. .,School of Medicine and Pharmacology, University of Western Australia, Fremantle Hospital, PO Box 480, Fremantle, 6959, WA, Australia.
| | - John Benjamin
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea.
| | - Celine Barnadas
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea. .,Infection and Immunity Division, Walter and Eliza Hall Institute, Parkville, VIC, Australia. .,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia.
| | - Leanne J Robinson
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea. .,Infection and Immunity Division, Walter and Eliza Hall Institute, Parkville, VIC, Australia. .,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia.
| | - Johanna H Kattenberg
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea. .,Infection and Immunity Division, Walter and Eliza Hall Institute, Parkville, VIC, Australia.
| | - Sarah Javati
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea.
| | - Rina P M Wong
- School of Medicine and Pharmacology, University of Western Australia, Fremantle Hospital, PO Box 480, Fremantle, 6959, WA, Australia.
| | - Anna Rosanas-Urgell
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea. .,Institute of Tropical Medicine, Antwerp, Belgium.
| | - Inoni Betuela
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea.
| | - Peter M Siba
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea.
| | - Ivo Mueller
- Infection and Immunity Division, Walter and Eliza Hall Institute, Parkville, VIC, Australia. .,Center de Recerca en Salut Internacional de Barcelona (CRESIB), Barcelona, Spain.
| | - Timothy M E Davis
- School of Medicine and Pharmacology, University of Western Australia, Fremantle Hospital, PO Box 480, Fremantle, 6959, WA, Australia.
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Genome mining offers a new starting point for parasitology research. Parasitol Res 2015; 114:399-409. [PMID: 25563615 DOI: 10.1007/s00436-014-4299-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 12/23/2014] [Indexed: 12/11/2022]
Abstract
Parasites including helminthes, protozoa, and medical arthropod vectors are a major cause of global infectious diseases, affecting one-sixth of the world's population, which are responsible for enormous levels of morbidity and mortality important and remain impediments to economic development especially in tropical countries. Prevalent drug resistance, lack of highly effective and practical vaccines, as well as specific and sensitive diagnostic markers are proving to be challenging problems in parasitic disease control in most parts of the world. The impressive progress recently made in genome-wide analysis of parasites of medical importance, including trematodes of Clonorchis sinensis, Opisthorchis viverrini, Schistosoma haematobium, S. japonicum, and S. mansoni; nematodes of Brugia malayi, Loa loa, Necator americanus, Trichinella spiralis, and Trichuris suis; cestodes of Echinococcus granulosus, E. multilocularis, and Taenia solium; protozoa of Babesia bovis, B. microti, Cryptosporidium hominis, Eimeria falciformis, E. histolytica, Giardia intestinalis, Leishmania braziliensis, L. donovani, L. major, Plasmodium falciparum, P. vivax, Trichomonas vaginalis, Trypanosoma brucei and T. cruzi; and medical arthropod vectors of Aedes aegypti, Anopheles darlingi, A. sinensis, and Culex quinquefasciatus, have been systematically covered in this review for a comprehensive understanding of the genetic information contained in nuclear, mitochondrial, kinetoplast, plastid, or endosymbiotic bacterial genomes of parasites, further valuable insight into parasite-host interactions and development of promising novel drug and vaccine candidates and preferable diagnostic tools, thereby underpinning the prevention and control of parasitic diseases.
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Manohar S, Satya Pavan V, Taylor D, Kumar D, Ponnan P, Wiesner L, Rawat DS. Highly active 4-aminoquinoline–pyrimidine based molecular hybrids as potential next generation antimalarial agents. RSC Adv 2015. [DOI: 10.1039/c4ra16032k] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Novel 4-aminoquinoline–pyrimidine based antimalarial hybrids were discovered to show potent activity against NF54 and Dd2 strains of P. falciparum.
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Affiliation(s)
- Sunny Manohar
- Department of Chemistry
- University of Delhi
- Delhi-110007
- India
| | - V. Satya Pavan
- Department of Chemistry
- University of Delhi
- Delhi-110007
- India
| | - Dale Taylor
- Division of Clinical Pharmacology
- Department of Medicine
- University of Cape Town
- Rondebosch 7700
- South Africa
| | - Deepak Kumar
- Department of Chemistry
- University of Delhi
- Delhi-110007
- India
| | - Prija Ponnan
- Department of Chemistry
- University of Delhi
- Delhi-110007
- India
| | - Lubbe Wiesner
- Division of Clinical Pharmacology
- Department of Medicine
- University of Cape Town
- Rondebosch 7700
- South Africa
| | - Diwan S. Rawat
- Department of Chemistry
- University of Delhi
- Delhi-110007
- India
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Mohd Abd Razak MR, Afzan A, Ali R, Amir Jalaluddin NF, Wasiman MI, Shiekh Zahari SH, Abdullah NR, Ismail Z. Effect of selected local medicinal plants on the asexual blood stage of chloroquine resistant Plasmodium falciparum. Altern Ther Health Med 2014; 14:492. [PMID: 25510573 PMCID: PMC4300612 DOI: 10.1186/1472-6882-14-492] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 12/11/2014] [Indexed: 11/16/2022]
Abstract
Background The development of resistant to current antimalarial drugs is a major challenge in achieving malaria elimination status in many countries. Therefore there is a need for new antimalarial drugs. Medicinal plants have always been the major source for the search of new antimalarial drugs. The aim of this study was to screen selected Malaysian medicinal plants for their antiplasmodial properties. Methods Each part of the plants were processed, defatted by hexane and sequentially extracted with dichloromethane, methanol and water. The antiplasmodial activities of 54 plant extracts from 14 species were determined by Plasmodium falciparum Histidine Rich Protein II ELISA technique. In order to determine the selectivity index (SI), all plant extracts demonstrating a good antiplasmodial activity were tested for their cytotoxicity activity against normal Madin-Darby Bovine Kidney (MDBK) cell lines by 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Results Twenty three extracts derived from Curcuma zedoaria (rhizome), Curcuma aeruginosa (rhizome), Alpinia galanga (rhizome), Morinda elliptica (leaf), Curcuma mangga (rhizome), Elephantopus scaber (leaf), Vitex negundo (leaf), Brucea javanica (leaf, root and seed), Annona muricata (leaf), Cinnamomun iners (leaf) and Vernonia amygdalina (leaf) showed promising antiplasmodial activities against the blood stage chloroquine resistant P. falciparum (EC50 < 10 μg/ml) with negligible toxicity effect to MDBK cells in vitro (SI ≥10). Conclusion The extracts belonging to eleven plant species were able to perturb the growth of chloroquine resistant P. falciparum effectively. The findings justified the bioassay guided fractionation on these plants for the search of potent antimalarial compounds or formulation of standardized extracts which may enhance the antimalarial effect in vitro and in vivo.
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60
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Manning JE, Satharath P, Gaywee J, Lopez MN, Lon C, Saunders DL. Fighting the good fight: the role of militaries in malaria elimination in Southeast Asia. Trends Parasitol 2014; 30:571-81. [PMID: 25455566 DOI: 10.1016/j.pt.2014.10.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 10/07/2014] [Accepted: 10/08/2014] [Indexed: 11/26/2022]
Abstract
Despite significant progress in malaria control in the Greater Mekong Subregion (GMS), malaria is still endemic, with more than 30 million people infected annually. Important gaps remain in case management, service delivery, prevention, and vector control, particularly in hard-to-reach mobile populations. Rapidly evolving drug resistance has created a new urgency to move aggressively toward elimination. However, no clear and cost-effective strategy has been identified. Although GMS militaries are under-recognized as a malaria transmission reservoir, they are an important focal point for elimination activities, given their high mobility, frequent malaria exposure, and potential for asymptomatic carriage. At the same time, military organizational capacity and proximity to other mobile populations could facilitate elimination efforts if relevant political barriers could be overcome. Here, we review considerations for military involvement in regional malaria elimination efforts.
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Affiliation(s)
- Jessica E Manning
- Department of Immunology and Medicine, US Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | | | | | | | - Chanthap Lon
- Department of Immunology and Medicine, US Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand; US Army Medical Component, Armed Forces Research Institute of Medical Sciences, Phnom Penh, Cambodia
| | - David L Saunders
- Department of Immunology and Medicine, US Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.
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Sahu R, Walker LA, Tekwani BL. In vitro and in vivo anti-malarial activity of tigecycline, a glycylcycline antibiotic, in combination with chloroquine. Malar J 2014; 13:414. [PMID: 25336038 PMCID: PMC4216846 DOI: 10.1186/1475-2875-13-414] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 10/10/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Several antibiotics have shown promising anti-malarial effects and have been useful for malarial chemotherapy, particularly in combination with standard anti-malarial drugs. Tigecycline, a semi-synthetic derivative of minocycline with a unique and novel mechanism of action, is the first clinically available drug in a new class of glycylcycline antibiotics. METHODS Tigecycline was tested in vitro against chloroquine (CQ)-sensitive (D6) and resistant strains (W2) of Plasmodium falciparum alone and in combination with CQ. Tigecycline was also tested in vivo in combination with CQ in Plasmodium berghei-mouse malaria model for parasitaemia suppression, survival and cure of the malaria infection. RESULTS Tigecycline was significantly more active against CQ-resistant (W2) than CQ-susceptible (D6) strain of P. falciparum. Tigecycline potentiated the anti-malarial action of CQ against the CQ-resistant strain of P. falciparum by more than seven-fold. Further, treatment of mice infected with P. berghei with tigecycline (ip) produced significant suppression in parasitaemia development and also prolonged the mean survival time. Treatment with as low as 3.7 mg/kg dose of tigecycline, once daily for four days, produced 77-91% suppression in parasitaemia. In vivo treatment with tigecycline in combination with subcurative doses of CQ produced complete cure in P. berghei-infected mice. CONCLUSION Results indicate prominent anti-malarial action of tigecycline in vitro and in vivo in combination with CQ and support further evaluation of tigecycline as a potential combination candidate for treatment of drug-resistant cases of malaria.
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Affiliation(s)
| | | | - Babu L Tekwani
- National Center for Natural Product Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy, University of Mississippi, University, MS 38677, USA.
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Lehane AM, Ridgway MC, Baker E, Kirk K. Diverse chemotypes disrupt ion homeostasis in the Malaria parasite. Mol Microbiol 2014; 94:327-39. [PMID: 25145582 DOI: 10.1111/mmi.12765] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2014] [Indexed: 01/09/2023]
Abstract
The antimalarial spiroindolones disrupt Plasmodium falciparum Na(+) regulation and induce an alkalinization of the parasite cytosol. It has been proposed that they do so by inhibiting PfATP4, a parasite plasma membrane P-type ATPase postulated to export Na(+) and import H(+) equivalents. Here, we screened the 400 antiplasmodial compounds of the open access 'Malaria Box' for their effects on parasite ion regulation. Twenty eight compounds affected parasite Na(+) and pH regulation in a manner consistent with PfATP4 inhibition. Six of these, with chemically diverse structures, were selected for further analysis. All six showed reduced antiplasmodial activity against spiroindolone-resistant parasites carrying mutations in pfatp4. We exposed parasites to incrementally increasing concentrations of two of the six compounds and in both cases obtained resistant parasites with mutations in pfatp4. The finding that diverse chemotypes have an apparently similar mechanism of action indicates that PfATP4 may be a significant Achilles' heel for the parasite.
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Affiliation(s)
- Adele M Lehane
- Research School of Biology, Australian National University, Canberra, ACT, 0200, Australia
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Roy N, Bhattacharyya S, Chakrabarty S, Laskar S, Babu SM, Bhattacharyya MK. Dominant negative mutant of Plasmodium Rad51 causes reduced parasite burden in host by abrogating DNA double-strand break repair. Mol Microbiol 2014; 94:353-66. [PMID: 25145341 DOI: 10.1111/mmi.12762] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2014] [Indexed: 01/05/2023]
Abstract
Malaria parasites survive through repairing a plethora of DNA double-stranded breaks (DSBs) experienced during their asexual growth. In Plasmodium Rad51 mediated homologous recombination (HR) mechanism and homology-independent alternative end-joining mechanism have been identified. Here we address whether loss of HR activity can be compensated by other DSB repair mechanisms. Creating a transgenic Plasmodium line defective in HR function, we demonstrate that HR is the most important DSB repair pathway in malarial parasite. Using mouse malaria model we have characterized the dominant negative effect of PfRad51(K143R) mutant on Plasmodium DSB repair and host-parasite interaction. Our work illustrates that Plasmodium berghei harbouring the mutant protein (PfRad51(K143R)) failed to repair DSBs as evidenced by hypersensitivity to DNA-damaging agent. Mice infected with mutant parasites lived significantly longer with markedly reduced parasite burden. To better understand the effect of mutant PfRad51(K143R) on HR, we used yeast as a surrogate model and established that the presence of PfRad51(K143R) completely inhibited DNA repair, gene conversion and gene targeting. Biochemical experiment confirmed that very low level of mutant protein was sufficient for complete disruption of wild-type PfRad51 activity. Hence our work provides evidence that HR pathway of Plasmodium could be efficiently targeted to curb malaria.
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Affiliation(s)
- Nabamita Roy
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, 500046, Andhra Pradesh, India
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64
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Sibley CH. Understanding drug resistance in malaria parasites: basic science for public health. Mol Biochem Parasitol 2014; 195:107-14. [PMID: 24927641 DOI: 10.1016/j.molbiopara.2014.06.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 05/25/2014] [Accepted: 06/03/2014] [Indexed: 01/09/2023]
Abstract
The worlds of basic scientists and those involved in treating patients and making public health decisions do not always intersect. Yet, assuring that when patients are treated, they are efficiently and completely cured, and that public health decisions are based on solid evidence requires a broad foundation of up to date basic research. Research on the malaria parasite, Plasmodium falciparum provides a useful illustration of the role that basic scientific studies have played in the very long relationship between humans and this deadly parasite. Drugs have always been a principal tool in malaria treatment. The ongoing struggle between evolution of resistance to antimalarials by the parasite and public health responses is used here as an illustration of the key contributions of basic scientists to this long history.
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Affiliation(s)
- Carol Hopkins Sibley
- World Wide Antimalarial Resistance Network, Department of Genome Sciences, University of Washington, Seattle, WA 98195-5065, USA.
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65
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Marchal E, Smithen DA, Uddin MI, Robertson AW, Jakeman DL, Mollard V, Goodman CD, MacDougall KS, McFarland SA, McFadden GI, Thompson A. Synthesis and antimalarial activity of prodigiosenes. Org Biomol Chem 2014; 12:4132-42. [DOI: 10.1039/c3ob42548g] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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66
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