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1.
Proc Natl Acad Sci U S A ; 117(44): 27627-27636, 2020 11 03.
Article in English | MEDLINE | ID: mdl-33087565

ABSTRACT

Dengue virus (DENV) subdues cell membranes for its cellular cycle by reconfiguring phospholipids in humans and mosquitoes. Here, we determined how and why DENV reconfigures phospholipids in the mosquito vector. By inhibiting and activating the de novo phospholipid biosynthesis, we demonstrated the antiviral impact of de novo-produced phospholipids. In line with the virus hijacking lipids for its benefit, metabolomics analyses indicated that DENV actively inhibited the de novo phospholipid pathway and instead triggered phospholipid remodeling. We demonstrated the early induction of remodeling during infection by using isotope tracing in mosquito cells. We then confirmed in mosquitoes the antiviral impact of de novo phospholipids by supplementing infectious blood meals with a de novo phospholipid precursor. Eventually, we determined that phospholipid reconfiguration was required for viral genome replication but not for the other steps of the virus cellular cycle. Overall, we now propose that DENV reconfigures phospholipids through the remodeling cycle to modify the endomembrane and facilitate formation of the replication complex. Furthermore, our study identified de novo phospholipid precursor as a blood determinant of DENV human-to-mosquito transmission.


Subject(s)
Aedes/virology , Dengue Virus/physiology , Dengue/transmission , Mosquito Vectors/virology , Phospholipids/biosynthesis , Aedes/enzymology , Animals , Cell Line , Cell Membrane/metabolism , Dengue/prevention & control , Dengue/virology , Dengue Virus/pathogenicity , Genome, Viral , Humans , Insect Proteins/genetics , Insect Proteins/metabolism , Lipid Metabolism/genetics , Metabolic Networks and Pathways/genetics , Metabolomics , Mosquito Vectors/enzymology , RNA Interference , RNA, Viral/metabolism , Virus Replication
2.
PLoS Pathog ; 15(12): e1008199, 2019 12.
Article in English | MEDLINE | ID: mdl-31815960

ABSTRACT

More than half of the world population is at risk of dengue virus (DENV) infection because of the global distribution of its mosquito vectors. DENV is an envelope virus that relies on host lipid membranes for its life-cycle. Here, we characterized how DENV hijacks the mosquito lipidome to identify targets for novel transmission-blocking interventions. To describe metabolic changes throughout the mosquito DENV cycle, we deployed a Liquid chromatography-high resolution mass spectrometry (LC-HRMS) workflow including spectral similarity annotation in cells, midguts and whole mosquitoes at different times post infection. We revealed a major aminophospholipid reconfiguration with an overall early increase, followed by a reduction later in the cycle. We phylogenetically characterized acylglycerolphosphate acyltransferase (AGPAT) enzyme isoforms to identify those that catalyze a rate-limiting step in phospholipid biogenesis, the acylation of lysophosphatidate to phosphatidate. We showed that DENV infection decreased AGPAT1, but did not alter AGPAT2 expression in cells, midguts and mosquitoes. Depletion of either AGPAT1 or AGPAT2 increased aminophospholipids and partially recapitulated DENV-induced reconfiguration before infection in vitro. However, only AGPAT1 depletion promoted infection by maintaining high aminophospholipid concentrations. In mosquitoes, AGPAT1 depletion also partially recapitulated DENV-induced aminophospholipid increase before infection and enhanced infection by maintaining high aminophospholipid concentrations. These results indicate that DENV inhibition of AGPAT1 expression promotes infection by increasing aminophospholipids, as observed in the mosquito's early DENV cycle. Furthermore, in AGPAT1-depleted mosquitoes, we showed that enhanced infection was associated with increased consumption/redirection of aminophospholipids. Our study suggests that DENV regulates aminophospholipids, especially phosphatidylcholine and phosphatidylethanolamine, by inhibiting AGPAT1 expression to increase aminophospholipid availability for virus multiplication.


Subject(s)
1-Acylglycerol-3-Phosphate O-Acyltransferase/metabolism , Dengue Virus/metabolism , Insect Proteins/metabolism , Mosquito Vectors/metabolism , Mosquito Vectors/virology , Aedes , Animals , Host-Parasite Interactions/physiology , Phospholipids/metabolism
3.
Parasitol Res ; 119(10): 3503-3515, 2020 Oct.
Article in English | MEDLINE | ID: mdl-32772176

ABSTRACT

Malaria, babesiosis, trypanosomosis, and leishmaniasis are some of the most life-threatening parasites, but the range of drugs to treat them is limited. An effective, safe, and low-cost drug with a large activity spectrum is urgently needed. For this purpose, an aryl amino alcohol derivative called Alsinol was resynthesized, screened in silico, and tested against Plasmodium, Babesia, Trypanosoma, and Leishmania. In silico Alsinol follows the Lipinski and Ghose rules. In vitro it had schizontocidal activity against Plasmodium falciparum and was able to inhibit gametocytogenesis; it was particularly active against late gametocytes. In malaria-infected mice, it showed a dose-dependent activity similar to chloroquine. It demonstrated a similar level of activity to reference compounds against Babesia divergens, and against promastigotes, and amastigotes stages of Leishmania in vitro. It inhibited the in vitro growth of two African animal strains of Trypanosoma but was ineffective in vivo in our experimental conditions. It showed moderate toxicity in J774A1 and Vero cell models. The study demonstrated that Alsinol has a large spectrum of activity and is potentially affordable to produce. Nevertheless, challenges remain in the process of scaling up synthesis, creating a suitable clinical formulation, and determining the safety margin in preclinical models.


Subject(s)
Amino Alcohols/pharmacology , Antiprotozoal Agents/pharmacology , Amino Alcohols/chemical synthesis , Amino Alcohols/chemistry , Animals , Antiprotozoal Agents/chemical synthesis , Antiprotozoal Agents/chemistry , Babesia/drug effects , Babesia/growth & development , Cell Survival/drug effects , Chlorocebus aethiops , Disease Models, Animal , Leishmania/drug effects , Leishmania/growth & development , Life Cycle Stages/drug effects , Mice , Plasmodium/drug effects , Plasmodium/growth & development , Protozoan Infections/drug therapy , Protozoan Infections/parasitology , Treatment Outcome , Trypanosoma/drug effects , Trypanosoma/growth & development , Vero Cells
4.
J Vector Borne Dis ; 57(2): 170-175, 2020.
Article in English | MEDLINE | ID: mdl-34290162

ABSTRACT

BACKGROUND & OBJECTIVES: In Colombian Amazonia, Uitoto indigenous people use a preparation of Curarea toxicofera (Menispermaceae) to prevent and treat malaria. To open the way for the production of a standardized herbal remedy, we compared the activity of the traditional preparation with laboratory preparations. METHODS: People were interviewed on their mode of use and preparation of what is considered the best remedy against fevers in this area. The herbal remedy was prepared according to the healer's recommendations. The plant was also submitted to continuous distillation and percolation extraction. The preparations were then tested against Plasmodium falciparum, in vitro. Traditional preparation and extract obtained by percolation were tested on Plasmodium berghei infected mice. Chemical profiles were also explored by thin-layer chromatography. RESULTS: Yields of extraction were around 7% in the preparations (percolation was the most efficient). The phytochemical profile showed a mix of steroids, flavonoids and alkaloids qualitatively similar in all preparations. In vitro, the extracts showed inhibitory concentration 50 <10µg/mL: the traditional preparation was almost three times less active than laboratory preparations. In vivo, percolation was also more active than traditional preparation, inhibiting 78% of the parasite growth at 400mg/kg/day by oral route. INTERPRETATION & CONCLUSION: Pharmacological activities suggest that both the original remedy (prepared according to traditional pharmacopeia) and the extracts obtained by percolation extraction exhibit relevant antiparasitic activity. C. toxicofera should therefore be considered for the elaboration of an improved traditional medicine by implementing toxicological studies and carefully following quality control guidelines for its preparation.


Subject(s)
Antimalarials/pharmacology , Malaria/drug therapy , Menispermaceae/chemistry , Phytochemicals/pharmacology , Plant Extracts/pharmacology , Plasmodium berghei/drug effects , Animals , Colombia , Humans , Malaria/parasitology , Medicine, Traditional , Mice , Plant Extracts/chemistry , Plant Extracts/isolation & purification , Plant Leaves/chemistry , Plants, Medicinal , Plasmodium falciparum/drug effects
5.
Molecules ; 24(24)2019 Dec 11.
Article in English | MEDLINE | ID: mdl-31835791

ABSTRACT

With an estimated annual incidence of one million cases, leishmaniasis is one of the top five vector-borne diseases. Currently available medical treatments involve side effects, including toxicity, non-specific targeting, and resistance development. Thus, new antileishmanial chemical entities are of the utmost interest to fight against this disease. The aim of this study was to obtain potential antileishmanial natural products from Psidium guajava leaves using a metabolomic workflow. Several crude extracts from P. guajava leaves harvested from different locations in the Lao People's Democratic Republic (Lao PDR) were profiled by liquid chromatography coupled to high-resolution mass spectrometry, and subsequently evaluated for their antileishmanial activities. The putative active compounds were highlighted by multivariate correlation analysis between the antileishmanial response and chromatographic profiles of P. guajava mixtures. The results showed that the pooled apolar fractions from P. guajava were the most active (IC50 = 1.96 ± 0.47 µg/mL). Multivariate data analysis of the apolar fractions highlighted a family of triterpenoid compounds, including jacoumaric acid (IC50 = 1.318 ± 0.59 µg/mL) and corosolic acid (IC50 = 1.01 ± 0.06 µg/mL). Our approach allowed the identification of antileishmanial compounds from the crude extracts in only a small number of steps and can be easily adapted for use in the discovery workflows of several other natural products.


Subject(s)
Antiprotozoal Agents/analysis , Metabolomics/methods , Phytochemicals/analysis , Psidium/chemistry , Antiprotozoal Agents/pharmacology , Chromatography, Liquid , Inhibitory Concentration 50 , Laos , Leishmania/drug effects , Mass Spectrometry , Phytochemicals/pharmacology , Plant Leaves/chemistry , Triterpenes/chemistry , Triterpenes/pharmacology
6.
Bioorg Med Chem Lett ; 27(8): 1820-1825, 2017 04 15.
Article in English | MEDLINE | ID: mdl-28291694

ABSTRACT

We report the design (in silico ADMET criteria), synthesis, cytotoxicity studies (HepG-2 cells), and biological evaluation of 15 hydrazine/hydrazide quinoxaline 1,4-di-N-oxide derivatives against the 3D7 chloroquine sensitive strain and FCR-3 multidrug resistant strain of Plasmodium falciparum and Leishmania infantum (axenic amastigotes). Fourteen of derivatives are novel quinoxaline 1,4-di-N-oxide derivatives. Compounds 18 (3D7 IC50=1.40µM, FCR-3 IC50=2.56µM) and 19 (3D7 IC50=0.24µM, FCR-3 IC50=2.8µM) were identified as the most active against P. falciparum, and they were the least cytotoxic (CC50-values>241µM) and most selective (SI>86). None of the compounds tested against L. infantum were considered to be active. Additionally, the functional role of the hydrazine and hydrazide structures were studied in the quinoxaline 1,4-di-N-oxide system.


Subject(s)
Antiprotozoal Agents/chemistry , Antiprotozoal Agents/pharmacology , Hydrazines/chemistry , Hydrazines/pharmacology , Quinoxalines/chemistry , Quinoxalines/pharmacology , Humans , Leishmania infantum/drug effects , Leishmaniasis, Visceral/drug therapy , Malaria, Falciparum/drug therapy , Plasmodium falciparum/drug effects , Structure-Activity Relationship
7.
Parasitol Res ; 116(7): 1955-1962, 2017 Jul.
Article in English | MEDLINE | ID: mdl-28508922

ABSTRACT

The in vivo efficacy of potential antimalarials is usually evaluated by direct microscopic determination of the parasitaemia of Plasmodium-infected mice on Giemsa-stained blood smears. This process is time-consuming, requires experienced technicians and is not automatable. Therefore, we optimized a SYBR Green I (SYBRG I) fluorescence-based assay to fluorometers commonly available in many research laboratories. This technique was originally developed to assess parasitaemia in humans by cytometry. We defined optimal conditions with Plasmodium berghei-infected mice, standard lysis buffer (Tris, EDTA, saponin and Triton), whole blood cells and 2 h staining incubation with SYBRG I 2X. The fluorescence background generated by uninfected whole blood cells was low (around 4.6%), and the linearity high (r 2 = 0.96), with parasitaemia ranging from 1.4 to 60%. The Bland-Altman plot showed a strong correlation between SYBRG I and Giemsa gold standard method; Z'-factor was >0.5. These findings suggest that our fluorescence-based assay is suitable for in vivo antimalarial drug assessment in a malaria murine model. It can help to overcome the human bias found with microscopic techniques.


Subject(s)
Antimalarials/therapeutic use , Malaria/drug therapy , Microbial Sensitivity Tests/methods , Plasmodium berghei/drug effects , Animals , Azure Stains , Benzothiazoles , Diamines , Fluorescence , Male , Mice , Organic Chemicals , Quinolines
8.
Oncology ; 91(2): 106-16, 2016.
Article in English | MEDLINE | ID: mdl-27250992

ABSTRACT

OBJECTIVES: Hepatocellular carcinoma (HCC) is the main type of primary liver cancer (PLC) worldwide, but cholangiocarcinoma (CCA) may be predominant in some specific regions of Southeast Asia. The aim of the present study was to delineate a pattern of Cambodian PLC patients attending the Calmette Hospital in the Cambodian capital Phnom Penh. MATERIALS AND METHODS: A total of 553 medical charts diagnosing PLCs from January 2003 to May 2015 were obtained from both the Oncology and Hepato-Gastroenterology Departments of the Calmette Hospital. RESULTS: HCC was the predominant type of PLC recorded, with 511 cases (92.4%), whereas CCA represented merely 7.6% (42 cases) of the overall series. Hepatitis B virus (HBV; 44.3%) and hepatitis C virus (HCV; 43%) infection rates were similar among the HCC patients, while small subsets of CCA patients were infected with HBV (15.4%) or HCV (11.5%). Most HCC (84%) and CCA (73.8%) patients received palliative treatment only. CONCLUSION: The present study indicates that HCC is the main form of primary hepatic neoplasm among PLC patients attending a hospital in Cambodia. HBV and HCV infections represented equivalent burdens and major contributing factors to HCC. Therefore, the implementation of prevention programs for these infectious agents should become a priority for health policy makers in the country.


Subject(s)
Carcinoma, Hepatocellular/epidemiology , Cholangiocarcinoma/epidemiology , Liver Neoplasms/epidemiology , Adult , Age Factors , Aged , Aged, 80 and over , Alanine Transaminase/blood , Alkaline Phosphatase/blood , Aspartate Aminotransferases/blood , Cambodia/epidemiology , Carcinoma, Hepatocellular/blood , Carcinoma, Hepatocellular/virology , Cholangiocarcinoma/blood , Cholangiocarcinoma/virology , Female , Hepatitis B, Chronic/epidemiology , Hepatitis C, Chronic/epidemiology , Humans , Life Style , Liver Neoplasms/blood , Liver Neoplasms/virology , Male , Middle Aged , Retrospective Studies , Risk Factors , Sex Factors , Time Factors , alpha-Fetoproteins/metabolism , gamma-Glutamyltransferase/blood
9.
Mem Inst Oswaldo Cruz ; 110(1): 106-13, 2015 Feb.
Article in English | MEDLINE | ID: mdl-25742270

ABSTRACT

This study examined whether the antidermatophytic activity of essential oils (EOs) can be used as an indicator for the discovery of active natural products against Leishmania amazonensis. The aerial parts of seven plants were hydrodistilled. Using broth microdilution techniques, the obtained EOs were tested against three strains of dermatophytes (Trichophyton mentagrophytes, Microsporum gypseum and Microsporum canis). To compare the EOs antifungal and antiparasitic effects, the EOs activities against axenic amastigotes of L. amazonensis were concurrently evaluated. For the most promising EOs, their antileishmanial activities against parasites infecting peritoneal macrophages of BALB/c mice were measured. The most interesting antifungal candidates were the EOs from Cymbopogon citratus, Otacanthus azureus and Protium heptaphyllum, whereas O. azureus, Piper hispidum and P. heptaphyllum EOs exhibited the lowest 50% inhibitory concentration (IC50) values against axenic amastigotes, thus revealing a certain correspondence between both activities. The P. hispidum EO was identified as the most promising product in the results from the infected macrophages model (IC50: 4.7 µg/mL, safety index: 8). The most abundant compounds found in this EO were sesquiterpenes, notably curzerene and furanodiene. Eventually, the evaluation of the antidermatophytic activity of EOs appears to be an efficient method for identifying new potential drugs for the treatment of L. amazonensis.


Subject(s)
Antifungal Agents/pharmacology , Antiprotozoal Agents/pharmacology , Leishmania/drug effects , Oils, Volatile/pharmacology , Animals , Axenic Culture , Burseraceae/metabolism , Cymbopogon/metabolism , Drug Substitution , Furans/administration & dosage , Gas Chromatography-Mass Spectrometry , Heterocyclic Compounds, 2-Ring/administration & dosage , Inhibitory Concentration 50 , Macrophages, Peritoneal/drug effects , Macrophages, Peritoneal/parasitology , Mice, Inbred BALB C , Microbial Sensitivity Tests , Microsporum/drug effects , Piper/metabolism , Plantago/metabolism , Sesquiterpenes/administration & dosage , Trichophyton/drug effects
10.
Phytochem Anal ; 26(2): 111-8, 2015.
Article in English | MEDLINE | ID: mdl-25431121

ABSTRACT

INTRODUCTION: Simalikalactone E (SkE) from Quassia amara, has been proved to be a valuable anti-malarial and anti-cancer compound. As SkE is very scarce, methods of quantitation are needed in order to optimise its isolation process and to determine pharmacokinetic data. OBJECTIVE: To validate methods using liquid chromatography coupled to mass spectrometry for the quantitation of SkE in plant extracts and in biological fluids. METHODS: High- and ultrahigh-performance liquid chromatography (UHPLC) coupled to ion trap mass spectrometry (MS) with single ion monitoring detection and to triple quadrupole-linear ion trap tandem mass spectrometry with multiple reaction monitoring detection methods were developed. Validation procedure was realised according to the International Conference on Harmonisation guideline. Methanol extracts of dried Quassia amara leaves, and mouse-blood samples obtained after various routes of administration, were analysed for SkE. RESULTS: Methods were validated and gave similar results regarding the content of SkE expressed per kilogram of dry leaves in the traditional decoction (160 ± 12 mg/kg) and in the methanol extract (93 ± 2 mg/kg). The recovery of the analyte from mouse blood ranged from 80.7 to 119.8%. Simalikalactone E was only detected using UHPLC-MS/MS (0.2 ± 0.03 mg/L) in mouse blood after intravenous injection: none was detected following intraperitoneal or oral gavage administration of SkE. CONCLUSION: The LC-MS methods were used for the quantitation of SkE in plant extracts and in mouse blood. These methods open the way for further protocol optimisation of SkE extraction and the determination of its pharmacokinetic data.


Subject(s)
Chromatography, High Pressure Liquid/methods , Plant Extracts/isolation & purification , Plant Leaves/chemistry , Quassia/chemistry , Quassins/isolation & purification , Tandem Mass Spectrometry/methods , Animals , Male , Mice , Plant Extracts/chemistry , Plants, Medicinal , Quassins/blood , Quassins/chemistry
11.
Molecules ; 19(2): 2166-80, 2014 Feb 18.
Article in English | MEDLINE | ID: mdl-24552985

ABSTRACT

We report the synthesis and antimalarial activities of eighteen quinoxaline and quinoxaline 1,4-di-N-oxide derivatives, eight of which are completely novel. Compounds 1a and 2a were the most active against Plasmodium falciparum strains. Structure-activity relationships demonstrated the importance of an enone moiety linked to the quinoxaline ring.


Subject(s)
Antimalarials/chemistry , Plasmodium falciparum/drug effects , Quinoxalines/chemistry , Structure-Activity Relationship , Antimalarials/chemical synthesis , Antimalarials/pharmacology , Cell Line , Humans , Molecular Structure , Parasitic Sensitivity Tests , Plasmodium falciparum/pathogenicity , Quinoxalines/chemical synthesis , Quinoxalines/pharmacology
12.
BMJ Glob Health ; 9(6)2024 Jun 06.
Article in English | MEDLINE | ID: mdl-38843896

ABSTRACT

INTRODUCTION: The global COVID-19 vaccine rollout has been impacted by socioeconomic disparities and vaccine hesitancy, but few studies examine reasons for changed attitudes. In Lao People's Democratic Republic (Lao PDR), a nationwide government-led initiative was developed in response to COVID-19, focused on community health ownership and trust in primary healthcare. The intervention team including health and governance sectors conducted capacity-building workshops with local staff and community representatives and visited villages for vaccination outreach. This study investigates the impact of this intervention on COVID-19 vaccine acceptance in rural communities. METHODS: Conducted in Xiengkhuang province, Lao PDR, from December 2022 to February 2023, the study employed a sequential mixed-methods research design. Data on vaccinated individuals from 25 villages were collected from 11 primary healthcare units; pre-post analysis was applied. Qualitative data, gathered through interviews and focus group discussions with villagers, village authorities, health staff and local government (n=102) in six villages, underwent inductive thematic analysis. RESULTS: First-dose vaccine uptake after the intervention increased significantly (6.9 times). Qualitative analysis identified key reasons for vaccination hesitancy: (1) mistrust due to rumours and past experiences; (2) poor communication and inconsistent messaging and (3) challenges in access for priority groups. Influencing factors during the intervention included (1) effective local-context communication; (2) leveraging existing community structures and influential individuals in a multisectoral approach and (3) increased community motivation through improved satisfaction, ownership and relationships. CONCLUSION: This study highlights the impact and methods of building trust with unreached populations in health interventions, emphasising locally led solutions. Successful reversal of vaccine hesitancy was achieved by addressing root causes and fostering ownership at community and local government levels through a 'positive approach'. This diverges from conventional supplemental immunisation activities and holds potential for systematically building trust between unreached populations and health systems. Further research could explore the impacts of routine vaccination for sustained improvements in health equity.


Subject(s)
COVID-19 Vaccines , COVID-19 , Rural Population , Trust , Vaccination Hesitancy , Humans , Laos , COVID-19 Vaccines/administration & dosage , COVID-19/prevention & control , Male , Female , Adult , Middle Aged , SARS-CoV-2 , Young Adult , Vaccination , Adolescent , Patient Acceptance of Health Care , Focus Groups
13.
Molecules ; 18(4): 4718-27, 2013 Apr 22.
Article in English | MEDLINE | ID: mdl-23609622

ABSTRACT

Malaria and leishmaniasis are two of the World's most important tropical parasitic diseases. Continuing with our efforts to identify new compounds active against malaria and leishmaniasis, twelve new 1,4-di-N-oxide quinoxaline derivatives were synthesized and evaluated for their in vitro antimalarial and antileishmanial activity against Plasmodium falciparum FCR-3 strain, Leishmania infantum and Leishmania amazonensis. Their toxicity against VERO cells (normal monkey kidney cells) was also assessed. The results obtained indicate that a cyclopentyl derivative had the best antiplasmodial activity (2.9 µM), while a cyclohexyl derivative (2.5 µM) showed the best activity against L. amazonensis, and a 3-chloropropyl derivative (0.7 µM) showed the best results against L. infantum. All these compounds also have a Cl substituent in the R7 position.


Subject(s)
Antiparasitic Agents/pharmacology , Leishmania/drug effects , Plasmodium/drug effects , Quinoxalines/pharmacology , Amides/chemistry , Animals , Antimalarials/chemistry , Antimalarials/pharmacology , Antimalarials/toxicity , Antiparasitic Agents/chemistry , Antiparasitic Agents/toxicity , Chlorocebus aethiops , Humans , Inhibitory Concentration 50 , Leishmania infantum/drug effects , Oxides/chemistry , Parasitic Sensitivity Tests , Plasmodium falciparum/drug effects , Quinoxalines/chemistry , Quinoxalines/toxicity , Structure-Activity Relationship , Vero Cells
14.
Microorganisms ; 11(9)2023 Aug 31.
Article in English | MEDLINE | ID: mdl-37764048

ABSTRACT

Genotype I, the penultimate HBV genotype to date, was granted the status of a bona fide genotype only in the XXIst century after some hesitations. The reason for these hesitations was that genotype I is a complex recombinant virus formed with segments from three original genotypes, A, C, and G. It was estimated that genotype I is responsible for only an infinitesimal fraction (<1.0%) of the chronic HBV infection burden worldwide. Furthermore, most probably due to its recent discovery and rarity, the natural history of infection with genotype I is poorly known in comparison with those of genotypes B or C that predominate in their area of circulation. Overall, genotype I is a minor genotype infecting ethnic minorities. It is endemic to the Southeast Asian Massif or Eastern Zomia, a vast mountainous or hilly region of 2.5 million km2 spreading from Eastern India to China, inhabited by a little more than 100 million persons belonging primarily to ethnic minorities speaking various types of languages (Tibeto-Burman, Austroasiatic, and Tai-Kadai) who managed to escape the authority of central states during historical times. Genotype I consists of two subtypes: I1, present in China, Laos, Thailand, and Vietnam; and I2, encountered in India, Laos, and Vietnam.

15.
Malar J ; 11: 67, 2012 Mar 09.
Article in English | MEDLINE | ID: mdl-22404785

ABSTRACT

BACKGROUND: Nitidine is thought to be the main active ingredient in several traditional anti-malarial remedies used in different parts of the world. The widespread use of these therapies stresses the importance of studying this molecule in the context of malaria control. However, little is known about its potential as an anti-plasmodial drug, as well as its mechanism of action. METHODS: In this study, the anti-malarial potential of nitidine was evaluated in vitro on CQ-sensitive and -resistant strains. The nitidine's selectivity index compared with cancerous and non-cancerous cell lines was then determined. In vivo assays were then performed, using the four-day Peter's test methodology. To gain information about nitidine's possible mode of action, its moment of action on the parasite cell cycle was studied, and its localization inside the parasite was determined using confocal microscopy. The in vitro abilities of nitidine to bind haem and to inhibit ß-haematin formation were also demonstrated. RESULTS: Nitidine showed similar in vitro activity in CQ-sensitive and resistant strains, and also a satisfying selectivity index (> 10) when compared with a non-cancerous cells line. Its in vivo activity was moderate; however, no sign of acute toxicity was observed during treatment. Nitidine's moment of action on the parasite cycle showed that it could not interfere with DNA replication; this was consistent with the observation that nitidine did not localize in the nucleus, but rather in the cytoplasm of the parasite. Nitidine was able to form a 1-1 complex with haem in vitro and also inhibited ß-haematin formation with the same potency as chloroquine. CONCLUSION: Nitidine can be considered a potential anti-malarial lead compound. Its ability to complex haem and inhibit ß-haematin formation suggests a mechanism of action similar to that of chloroquine. The anti-malarial activity of nitidine could therefore be improved by structural modification of this molecule to increase its penetration of the digestive vacuole in the parasite, where haemoglobin metabolization takes place.


Subject(s)
Antimalarials/pharmacology , Benzophenanthridines/pharmacology , Plasmodium falciparum/drug effects , Plasmodium/drug effects , Zanthoxylum/chemistry , Animals , Antimalarials/isolation & purification , Benzophenanthridines/isolation & purification , Cell Survival/drug effects , Cells, Cultured , Chlorocebus aethiops , Cytoplasm/drug effects , Cytoplasm/parasitology , Drug Resistance , Erythrocytes/drug effects , Erythrocytes/parasitology , HeLa Cells , Heme/metabolism , Hemeproteins/antagonists & inhibitors , Hemeproteins/biosynthesis , Humans , Inhibitory Concentration 50 , Malaria , Mice , Microscopy, Confocal , Plasmodium/growth & development , Plasmodium falciparum/growth & development , Vero Cells
16.
Exp Parasitol ; 130(4): 341-7, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22374406

ABSTRACT

Quassia amara L. (Simaroubaceae) is a species widely used as tonic and is claimed to be an efficient antimalarial all over the Northern part of the Amazon basin. Quassinoid compound Simalikalactone D (SkD) has been shown to be one of the molecules responsible for the antiplasmodial activity of a watery preparation made out of juvenile fresh leaves of this plant. Because of its strong antimalarial activity, we decided to have a further insight of SkD pharmacological properties, alone or in association with classical antimalarials. At concentrations of up to 200µM, we showed herein that SkD did not exert any apoptotic or necrotic activities in vitro on lymphoblastic cells. However, an antiproliferative effect was evident at concentrations higher than 45nM. SkD was inefficient at inhibiting heme biomineralization and the new permeability pathways induced by the parasite in the host erythrocyte membrane. With respect to Plasmodium falciparum erythrocytic stages, SkD was almost inactive on earlier and later parasite stages, but potently active at the 30th h of parasite cycle when DNA replicates in mature trophozoites. In vitro combination studies with conventional antimalarial drugs showed that SkD synergizes with atovaquone (ATO). The activity of ATO on the Plasmodium mitochondrial membrane potential was enhanced by SkD, which on its own had a poor effect on this cellular parameter.


Subject(s)
Antimalarials/pharmacology , Plasmodium falciparum/drug effects , Plasmodium yoelii/drug effects , Quassia/chemistry , Quassins/pharmacology , Cell Line/drug effects , Cell Membrane Permeability/drug effects , Cell Proliferation/drug effects , Erythrocyte Membrane/drug effects , Erythrocyte Membrane/metabolism , Erythrocytes/drug effects , Erythrocytes/parasitology , Heme/metabolism , Humans , Inhibitory Concentration 50 , Plant Extracts/pharmacology , Plant Leaves/chemistry
17.
Mem Inst Oswaldo Cruz ; 107(6): 820-3, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22990975

ABSTRACT

The effectiveness of methylene blue (MB) combined with pyrimethamine (PYR), chloroquine (CQ) or quinine (Q) was examined in a classical four-day suppressive test against a causative agent of rodent malaria, Plasmodium berghei. A marked potentiation was observed when MB was administered at a non-curative dose of 15 mg/kg/day in combination with PYR (0.19 mg/kg/day) or Q (25 mg/kg/day). No synergy was found between MB (15 mg/Kg) and CQ (0.75 mg/Kg). Our results suggest that the combination of MB with PYR or Q may improve the efficacy of these currently used antimalarial drugs.


Subject(s)
Antimalarials/therapeutic use , Enzyme Inhibitors/therapeutic use , Malaria/drug therapy , Methylene Blue/therapeutic use , Animals , Chloroquine/therapeutic use , Disease Models, Animal , Drug Therapy, Combination/methods , Male , Mice , Plasmodium berghei/drug effects , Pyrimethamine/therapeutic use , Quinine/therapeutic use
18.
Molecules ; 17(8): 9451-61, 2012 Aug 07.
Article in English | MEDLINE | ID: mdl-22871647

ABSTRACT

Malaria and leishmaniasis are two of the World's most important tropical parasitic diseases. Thirteen new 2-cyano-3-(4-phenylpiperazine-1-carboxamido) quinoxaline 1,4-dioxide derivatives (CPCQs) were synthesized and evaluated for their in vitro antimalarial and antileishmanial activity against erythrocytic forms of Plasmodium falciparum and axenic forms of Leishmania infantum. Their toxicity against VERO cells (normal monkey kidney cells) was also assessed. None of the tested compounds was efficient against Plasmodium, but two of them showed good activity against Leishmania. Toxicity on VERO was correlated with leishmanicidal properties.


Subject(s)
Antiprotozoal Agents/pharmacology , Leishmania infantum/drug effects , Piperazines/pharmacology , Plasmodium falciparum/drug effects , Quinoxalines/pharmacology , Animals , Antiprotozoal Agents/chemical synthesis , Catalysis , Chlorocebus aethiops , Dimethylformamide/chemistry , Drug Evaluation, Preclinical , Ethylamines/chemistry , Inhibitory Concentration 50 , Piperazines/chemical synthesis , Quinoxalines/chemical synthesis , Solvents/chemistry , Structure-Activity Relationship , Vero Cells
19.
EClinicalMedicine ; 52: 101582, 2022 Oct.
Article in English | MEDLINE | ID: mdl-35923426

ABSTRACT

Background: Laos is considered highly endemic for persistent infection with hepatitis B virus (HBV). To eliminate this burden, it has gradually implemented universal anti-hepatitis B immunisation of newborns over the past two decades. Methods: Using VIKIA® HBsAg, a rapid test for the qualitative detection of the HBV surface antigen, we conducted between Sep 1st, 2020 and Aug 31st, 2021 the largest prospective prevalence survey ever in Laos. This survey included blood donors (BD, n = 42,277), patients attending care in capital and provincial hospitals (n = 37,347) including attending mothers (n = 20,548), HIV-infected patients (n = 7439, recruited from 2009 to 2020), students from the Health Sciences University (n = 609), and outpatients (n = 350) coming for diagnosis at the Center Infectiology Lao-Christophe Mérieux in Vientiane. In total, 88,022 persons were tested, representing approximately 1.22% of the national population. To reach a reasonable estimate of HBsAg prevalence in Laos, we segmented the population according to three variables, age (≤20 years as a cut-off), sex, and geographical origin. BD values were used to estimate HBsAg prevalence in patients aged <20 while hospital survey prevalence was used to estimate the prevalence in those aged older than 20 years. Findings: We observed an HBsAg seroprevalence ranging from 2.6% in blood donors to 8.0% in HIV-infected patients. In BD, men were significantly more at risk to be carriers than women (RR = 1.2, P = 0.00063). For BD, attending mothers, or HIV-infected patients, HBsAg was significantly more prevalent in northern Laos (5.1-8.4%) than in central (2.0-8.1%) or southern parts of the country (2.2-6.9%), thereby delineating a North-to-South gradient. Interpretation: We considered that HBsAg prevalence probably ranges between 5.0% and 6.0% of the total population. Thus, we consider that Laos may no longer be highly endemic for chronic HBV infection but rather a country with intermediate endemicity. Funding: The funding sources were the Agence Universitaire de la Francophonie, the French Government, the French Institute for Sustainable Development (IRD), and European Union's Horizon 2020 Marie Sklodowska-Curie Actions (MSCA) - Research and Innovation Staff Exchange - (RISE) under grant agreement N° 823935.

20.
Sci Rep ; 12(1): 13525, 2022 08 08.
Article in English | MEDLINE | ID: mdl-35941193

ABSTRACT

The Central Andes of Peru are a region of great concern regarding pesticide risk to the health of local communities. Therefore, we conducted an observational study to assess the level of pesticide contamination among Andean people. Analytical chemistry methods were used to measure the concentrations of 170 pesticide-related compounds in hair samples from 50 adult Andean subjects living in rural and urban areas. As part of the study, a questionnaire was administered to the subjects to collect information regarding factors that increase the risk of pesticide exposure. Our results indicate that Andean people are strongly exposed to agrochemicals, being contaminated with a wide array of pesticide-related compounds at high concentration levels. Multivariate analyses and geostatistical modeling identified sociodemographic factors associated with rurality and food origin that increase pesticide exposure risk. The present study represents the first comprehensive investigation of pesticide-related compounds detected in body samples collected from people living in the Central Andes of Peru. Our findings pinpoint an alarming environmental situation that threatens human health in the region and provide a rationale for improving public policies to protect local communities.


Subject(s)
Pesticides , Adult , Agrochemicals/analysis , Environmental Exposure/analysis , Humans , Peru , Pesticides/analysis
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