RESUMO
The spontaneously hypertensive rats (SHRs) have enhanced palatability for NaCl taste as measured by the increased number of hedonic versus aversive responses to intraoral infusion (1 mL/1 min) of 0.3 M NaCl, in a taste reactivity test in euhydrated condition or after 24 h of water deprivation + 2 h of partial rehydration (WD-PR). SHRs also ingested more sucrose than normotensive rats, without differences in quinine hydrochloride intake. Here, we investigated the palatability of SHRs (n = 8-10) and normotensive Holtzman rats (n = 8-10) to sucrose and quinine sulphate infused intraorally in the same conditions that NaCl palatability was increased in SHRs. SHRs had similar number of hedonic responses to 2% sucrose in euhydrated condition (95 ± 19) or after WD-PR (142 ± 25), responses increased when compared with normotensive rats in euhydrated condition (13 ± 3) or after WD-PR (21 ± 6). SHRs also showed increased number of aversive responses to 1.4 mM quinine sulphate compared with normotensive rats, whether in euhydrated condition (86 ± 6, vs. normotensive: 54 ± 7) or after WD-PR (89 ± 9, vs. normotensive: 40 ± 9). The results suggest that similar to NaCl taste, sweet taste responses are increased in SHRs and resistant to challenges in bodily fluid balance. They also showed a more intense aversive response in SHRs to bitter taste compared with normotensives. This suggests that the enhanced response of SHRs to taste rewards does not correspond to a decreased response to a typical aversive taste.
Assuntos
Quinina , Cloreto de Sódio , Ratos , Animais , Ratos Endogâmicos SHR , Cloreto de Sódio/farmacologia , Quinina/farmacologia , Paladar/fisiologia , Ratos Sprague-Dawley , Sacarose/farmacologiaRESUMO
An animal model of voluntary oral morphine consumption would allow for a pre-clinical evaluation of new treatments aimed at reducing opioid intake in humans. However, the main limitation of oral morphine consumption in rodents is its bitter taste, which is strongly aversive. Taste aversion is often overcome by the use of adulterants, such as sweeteners, to conceal morphine taste or bitterants in the alternative bottle to equalize aversion. However, the adulterants' presence is the cause for consumption choice and, upon removal, the preference for morphine is not preserved. Thus, current animal models are not suitable to study treatments aimed at reducing consumption elicited by morphine itself. Since taste preference is a learned behavior, just-weaned rats were trained to accept a bitter taste, adding the bitterant quinine to their drinking water for one week. The latter was followed by allowing the choice of quinine or morphine (0.15 mg/mL) solutions for two weeks. Then, quinine was removed, and the preference for morphine against water was evaluated. Using this paradigm, we show that rats highly preferred the consumption of morphine over water, reaching a voluntary morphine intake of 15 mg/kg/day. Morphine consumption led to significant analgesia and hyperlocomotion, and to a marked deprivation syndrome following the administration of the opioid antagonist naloxone. Voluntary morphine consumption was also shown to generate brain oxidative stress and neuroinflammation, signs associated with opioid dependence development. We present a robust two-bottle choice animal model of oral morphine self-administration for the evaluation of therapeutic interventions for the treatment of morphine dependence.
Assuntos
Dependência de Morfina , Transtornos Relacionados ao Uso de Opioides , Animais , Modelos Animais de Doenças , Morfina/farmacologia , Transtornos Relacionados ao Uso de Opioides/tratamento farmacológico , Quinina/farmacologia , Quinina/uso terapêutico , Ratos , Paladar , ÁguaRESUMO
With about 400,000 annual deaths worldwide, malaria remains a public health burden in tropical and subtropical areas, especially in low-income countries. Selection of drug-resistant Plasmodium strains has driven the need to explore novel antimalarial compounds with diverse modes of action. In this context, biodiversity has been widely exploited as a resourceful channel of biologically active compounds, as exemplified by antimalarial drugs such as quinine and artemisinin, derived from natural products. Thus, combining a natural product library and quantitative structure-activity relationship (QSAR)-based virtual screening, we have prioritized genuine and derivative natural compounds with potential antimalarial activity prior to in vitro testing. Experimental validation against cultured chloroquine-sensitive and multi-drug-resistant P. falciparum strains confirmed the potent and selective activity of two sesquiterpene lactones (LDT-597 and LDT-598) identified in silico. Quantitative structure-property relationship (QSPR) models predicted absorption, distribution, metabolism, and excretion (ADME) and physiologically based pharmacokinetic (PBPK) parameters for the most promising compound, showing that it presents good physiologically based pharmacokinetic properties both in rats and humans. Altogether, the in vitro parasite growth inhibition results obtained from in silico screened compounds encourage the use of virtual screening campaigns for identification of promising natural compound-based antimalarial molecules.
Assuntos
Antimaláricos/química , Antimaláricos/farmacologia , Produtos Biológicos/química , Produtos Biológicos/farmacologia , Artemisininas/farmacologia , Plasmodium falciparum/efeitos dos fármacos , Relação Quantitativa Estrutura-Atividade , Quinina/farmacologiaRESUMO
Optochin susceptibility testing is a major assay used for presumptive identification of Streptococcus pneumoniae. Still, atypical optochin-resistant (Optr) pneumococci have been reported and this phenotype has been attributed to nucleotide substitutions in the genes coding for the F0F1ATPase. While substitutions in the atpC gene (c-subunit of ATPase) are more common and better characterized, data on mutations in the atpA (a-subunit) are still limited. We have characterized five Optr isolates presenting alterations in the atpA (Trp206Cys in four isolates and Trp206Ser in one isolate), constituting the first report of such mutations in Brazil. Most of the Optr isolates consisted of heterogeneous populations. Except for Opt MICs and the nucleotide changes in the atpA gene, Optr and Opts subpopulations originating from the same culture had identical characteristics. In addition, we compared phenotypic and genetic characteristics of these atpA mutants with those of atpC mutants previously identified in Brazil. No structural alterations were detected among predicted proteins, regardless of mutations in the coding gene, suggesting that, despite the occurrence of mutations, protein structures tend to be highly conserved, ensuring their functionalities. Phylogenetic analysis revealed that atypical Optr strains are true pneumococci and Opt resistance does not represent any apparent selective advantage for clinical isolates.
Assuntos
Farmacorresistência Bacteriana/genética , Genes Bacterianos , Mutação/genética , Quinina/análogos & derivados , Streptococcus pneumoniae/efeitos dos fármacos , Sequência de Bases , Brasil , Simulação por Computador , Farmacorresistência Bacteriana/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Modelos Moleculares , Fenótipo , Filogenia , Subunidades Proteicas/química , Quinina/farmacologiaRESUMO
Neospora caninum is an apicomplexan parasite that causes abortion in cattle, resulting in significant economic losses. There is no commercial treatment for neosporosis, and drug repositioning is a fast strategy to test possible candidates against N. caninum. In this article, we describe the effects of atovaquone, chloroquine, quinine, primaquine and tetracycline on N. caninum proliferation. The IC50 concentrations in N. caninum were compared to the current information based on previous studies for Plasmodium and Toxoplasma gondii, correlating to the described mechanisms of action of each tested drug. The inhibitory patterns indicate similarities and differences among N. caninum, Plasmodium and T. gondii. For example, atovaquone demonstrates high antiparasitic activity in all the analyzed models, while chloroquine does not inhibit N. caninum. On the other hand, tetracycline is effective against Plasmodium and N. caninum, despite its low activity in T. gondii models. The repurposing of antimalarial drugs in N. caninum is a fast and inexpensive way to develop novel formulations using well-established compounds.
Assuntos
Antimaláricos , Neospora/efeitos dos fármacos , Antimaláricos/farmacologia , Atovaquona/farmacologia , Cloroquina/farmacologia , Primaquina/farmacologia , Quinina/farmacologia , Tetraciclinas/farmacologiaRESUMO
Abstract Neospora caninum is an apicomplexan parasite that causes abortion in cattle, resulting in significant economic losses. There is no commercial treatment for neosporosis, and drug repositioning is a fast strategy to test possible candidates against N. caninum. In this article, we describe the effects of atovaquone, chloroquine, quinine, primaquine and tetracycline on N. caninum proliferation. The IC50 concentrations in N. caninum were compared to the current information based on previous studies for Plasmodium and Toxoplasma gondii, correlating to the described mechanisms of action of each tested drug. The inhibitory patterns indicate similarities and differences among N. caninum, Plasmodium and T. gondii. For example, atovaquone demonstrates high antiparasitic activity in all the analyzed models, while chloroquine does not inhibit N. caninum. On the other hand, tetracycline is effective against Plasmodium and N. caninum, despite its low activity in T. gondii models. The repurposing of antimalarial drugs in N. caninum is a fast and inexpensive way to develop novel formulations using well-established compounds.
Resumo Neospora caninum é um parasita Apicomplexa relacionado a abortos no gado bovino, que resultam em impactos econômicos. Não há tratamento comercial para neosporosis e o reposicionamento de drogas indica uma estratégia rápida para testar candidatos anti-N. caninum. Neste artigo, são descritos os efeitos da atovaquona, cloroquina, quinino, primaquine e tetraciclina na proliferação de N. caninum. As concentrações IC50 em N. caninum foram comparadas com a informação disponível, baseada em estudos publicados previamente para Plasmodium e Toxoplasma gondii, incluindo a correlação com os mecanismos de ação descritos para cada droga testada. Os padrões de inibição indicam pontos de similaridades e diferenças entre N. caninum, Plasmodium e T. gondii. Por exemplo, a atovaquona demonstra uma alta atividade antiparasitária em todos os modelos testados, enquanto a cloroquina não inibe N. caninum. Por outro lado, a tetraciclina é efetiva contra Plasmodium e N. caninum, em contraste com a baixa atividade em modelos de T. gondii. O reposicionamento de drogas antimaláricas em N. caninum é uma forma rápida e de baixo custo para o desenvolvimento de novas formulações que usam compostos bem estabelecidos.
Assuntos
Neospora/efeitos dos fármacos , Antimaláricos/farmacologia , Primaquina/farmacologia , Quinina/farmacologia , Tetraciclinas/farmacologia , Cloroquina/farmacologia , Atovaquona/farmacologiaRESUMO
AIM: Chagas disease is a tropical disease caused by the hemoflagellate protozoan Trypanosoma cruzi. There is no vaccine for Chagas disease and available drugs (e.g., benznidazole) are effective only during the acute phase, displaying a variable curative activity in the established chronic form of the disease. New leads with high efficacy and better toxicity profiles are urgently required. Materials & methods: A library of novel quinine derivatives was synthesized using Heck chemistry and evaluated against the various developmental forms of T. cruzi. RESULTS AND CONCLUSION: Several novel quinine analogs with trypanocidal activity have been identified with the para-nitro-substituted derivative displaying a submicromolar IC50, which is 83-times lower than quinine and three-times lower than benznidazole. Transmission electron microscopy analysis demonstrated that these compounds induced a marked vacuolization of the kinetoplast of intracellular amastigotes and cell-derived trypomastigotes.
Assuntos
Doença de Chagas/tratamento farmacológico , Doença de Chagas/parasitologia , Quinina/análogos & derivados , Quinina/farmacologia , Tripanossomicidas/síntese química , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Animais , Sobrevivência Celular/efeitos dos fármacos , Chlorocebus aethiops , Relação Dose-Resposta a Droga , Microscopia Eletrônica de Transmissão , Conformação Molecular , Testes de Sensibilidade Parasitária , Quinina/síntese química , Quinina/química , Relação Estrutura-Atividade , Tripanossomicidas/química , Células VeroRESUMO
Subjects trained in successive positive contrast are usually given an appetitive stimulus of relatively low quality during a pre-shift, followed by exposure to a significantly greater quality of the same stimulus. Enhanced responsiveness to the high-quality stimulus during the post-shift phase, compared to a control group that receives the superior reward in both phases, is taken as an index of successive positive contrast. Successive positive contrast reports are rare, probably due to performance limitations inherent to the experimental protocols available. We exposed infant rats (14 days old at the start of training) to .1% or .01% quinine during 4, 10 min, trials (pre-shift phase). All animals were then given two trials of exposure to .01% quinine (post-shift phase). During the pre-shift the level of intake was greater in pups stimulated with the relatively less aversive .01% quinine solution. These animals also exhibited, compared to those stimulated with .1% quinine, lower emission of the aversive response paw treading. During the post-shift phase, the group that had been exposed to .1% quinine exhibited significantly greater intake of .01% quinine, along with a reduction in the emission of paw treading and an enhancement in paw licking, an ingestive, appetitive response. Altogether, the evidence is suggestive of the emergence of consummatory successive positive contrast during the second week of life of the rat. To our knowledge, this is the first evidence of positive contrast using an aversive solution.
Assuntos
Comportamento Apetitivo/fisiologia , Comportamento Consumatório/fisiologia , Aprendizagem/fisiologia , Quinina/farmacologia , Paladar/fisiologia , Fatores Etários , Animais , Feminino , Aprendizagem/efeitos dos fármacos , Masculino , Quinina/administração & dosagem , Ratos , Ratos WistarRESUMO
OBJECTIVE: To investigate whether the recurrence of infection by Plasmodium falciparum in patients from the Brazilian Amazon was caused by an inadequate exposure to quinine. METHODS: A retrospective study was carried out using blood samples from patients with slide-confirmed infection by P. falciparum, classified according to the parasitological response after 28 days of follow-up. Quinine and doxycycline were measured in plasma samples by high-performance liquid chromatography. A statistical model was used to estimate parasite clearance rates. RESULTS: Six of 40 patients who met the criteria for inclusion in the study showed recurrence of parasitaemia within 28 days after the commencement of treatment. A group of six patients with adequate parasitological response was formed to avoid bias when the variables were compared. Parasitaemia at admission was similar in both groups. Plasma quinine concentrations were similar in both groups on days 1, 2 and 3 and ranged from 1.07 to 4.35 µg/ml in cured patients and from 1.1 to 3.2 µg/ml in patients with parasite recurrence. Concentrations of doxycycline were similar in both groups on day 3. The parasite clearance rate constant was 0.131 ± 0.16 h in the cured patients and 0.117 ± 0.02 h in those showing recurrence. The slope half-life in the cured patients was 4.8 h and 5.4 h in recurrence cases. The hillslope of the cured group (14.24) increased sharply compared to the recurrence group (4.13). CONCLUSION: There is evidence of a decreased in vivo sensitivity to quinine of P. falciparum strains in the Brazilian Amazon basin.
Assuntos
Antimaláricos/uso terapêutico , Doxiciclina/uso terapêutico , Malária Falciparum/tratamento farmacológico , Quinina/uso terapêutico , Adulto , Animais , Antimaláricos/administração & dosagem , Antimaláricos/farmacologia , Brasil/epidemiologia , Doxiciclina/administração & dosagem , Doxiciclina/farmacologia , Resistência a Medicamentos , Quimioterapia Combinada , Feminino , Humanos , Malária Falciparum/microbiologia , Masculino , Plasmodium falciparum/efeitos dos fármacos , Quinina/administração & dosagem , Quinina/farmacologia , Recidiva , Estudos Retrospectivos , Adulto JovemRESUMO
BACKGROUND: In models of temporal lobe epilepsy and in patients with this pathology, high frequency oscillations called fast ripples (FRs, 250-600 Hz) can be observed. FRs are considered potential biomarkers for epilepsy and, in the light of many in vitro and in silico studies, we thought that electrical synapses mediated by gap junctions might possibly modulate FRs in vivo. METHODS: Animals with spontaneous recurrent seizures induced by pilocarpine administration were implanted with movable microelectrodes in the right anterior and posterior hippocampus to evaluate the effects of gap junction blockers administered in the entorhinal cortex. The effects of carbenoxolone (50 nmoles) and quinine (35 pmoles) on the mean number of spontaneous FR events (occurrence of FRs), as well as on the mean number of oscillation cycles per FR event and their frequency, were assessed using a specific algorithm to analyze FRs in intracranial EEG recordings. RESULTS: We found that these gap junction blockers decreased the mean number of FRs and the mean number of oscillation cycles per FR event in the hippocampus, both during and at different times after carbenoxolone and quinine administration. CONCLUSION: These data suggest that FRs may be modulated by gap junctions, although additional experiments in vivo will be necessary to determine the precise role of gap junctions in this pathological activity associated with epileptogenesis.
Assuntos
Carbenoxolona/uso terapêutico , Eletroencefalografia , Hipocampo/patologia , Quinina/uso terapêutico , Convulsões/tratamento farmacológico , Animais , Comportamento Animal , Carbenoxolona/administração & dosagem , Carbenoxolona/farmacologia , Hipocampo/efeitos dos fármacos , Masculino , Quinina/administração & dosagem , Quinina/farmacologia , Ratos Wistar , RecidivaRESUMO
The in vitro susceptibilities of 30 isolates of Plasmodium vivax to a number of antimalarials (chloroquine [CQ], mefloquine, amodiaquine, quinine, and artesunate [AS]) were evaluated. The isolates came from the region of Urabá in Colombia, in which malaria is endemic, and were evaluated by the schizont maturation test. The 50% inhibitory concentration (IC50) was 0.6 nM (95% confidence interval [CI], 0.3 to 1.0 nM) for artesunate, 8.5 nM (95% CI, 5.6 to 13.0 nM) for amodiaquine, 23.3 nM (95% CI, 12.4 to 44.1 nM) for chloroquine, 55.6 nM (95% CI, 36.8 to 84.1 nM) for mefloquine, and 115.3 nM (95% CI, 57.7 to 230.5 nM) for quinine. The isolates were classified according to whether the initial parasites were mature or immature trophozoites (Tfz). It was found that the IC50s for chloroquine and artesunate were significantly different in the two aforementioned groups (P < 0.001). The IC50s of CQ and AS were higher in the isolates from mature Tfz (CQ, 39.3 nM versus 17 nM; AS, 1.4 nM versus 0.3 nM), and 10% of the isolates showed lower susceptibilities to one of the antimalarial drugs, 13.3% to two antimalarial drugs, and 3.3% to more than three antimalarial drugs. It should be highlighted that despite the extensive use of chloroquine in Colombia, P. vivax continues to be susceptible to antimalarials. This is the first report, to our knowledge, showing in vitro susceptibilities of P. vivax isolates to antimalarials in Colombia.
Assuntos
Antimaláricos/farmacologia , Malária Vivax/tratamento farmacológico , Plasmodium vivax/efeitos dos fármacos , Amodiaquina/farmacologia , Artemisininas/farmacologia , Artesunato , Cloroquina/farmacologia , Colômbia , Resistência a Medicamentos , Malária Vivax/parasitologia , Mefloquina/farmacologia , Testes de Sensibilidade Parasitária , Plasmodium vivax/isolamento & purificação , Quinina/farmacologiaRESUMO
INTRODUCTION: Despite efforts to control malaria, around 10% of the world population is at risk of acquiring this disease. Plasmodium falciparum accounts for the majority of severe cases and deaths. Malaria control programs have failed due to the therapeutic failure of first-line antimalarials and to parasite resistance. Thus, new and better therapeutic alternatives are required. Proteomic analysis allows determination of protein expression levels under drug pressure, leading to the identification of new therapeutic drug targets and their mechanisms of action. OBJECTIVE: The aim of this study was to analyze qualitatively the expression of P.falciparum trophozoite proteins (strain ITG2), after exposure to antimalarial drugs, through a proteomic approach. MATERIALS AND METHODS: In vitro cultured synchronized parasites were treated with quinine, mefloquine and the natural antiplasmodial diosgenone. Protein extracts were prepared and analyzed by two-dimensional electrophoresis. The differentially expressed proteins were selected and identified by MALDI-TOF mass spectrometry. RESULTS: The following proteins were identified among those differentially expressed in the parasite in the presence of the drugs tested: enolase (PF10_0155), calcium-binding protein (PF11_0098), chaperonin (PFL0740c), the host cell invasion protein (PF10_0268) and proteins related to redox processes (MAL8P1.17). These findings are consistent with results of previous studies where the parasite was submitted to pressure with other antimalarial drugs. CONCLUSION: The observed changes in the P. falciparum trophozoite protein profile induced by antimalarial drugs involved proteins mainly related to the general stress response.
Assuntos
Antiprotozoários/farmacologia , Mefloquina/farmacologia , Plasmodium falciparum/efeitos dos fármacos , Proteínas de Protozoários/biossíntese , Quinina/farmacologia , Compostos de Espiro/farmacologia , Triterpenos/farmacologia , Sequência de Aminoácidos , Eletroforese em Gel Bidimensional , Eritrócitos/parasitologia , Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas de Choque Térmico/biossíntese , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/isolamento & purificação , Humanos , Técnicas In Vitro , Concentração Inibidora 50 , Dados de Sequência Molecular , Plasmodium falciparum/crescimento & desenvolvimento , Plasmodium falciparum/metabolismo , Proteoma , Proteínas de Protozoários/genética , Proteínas de Protozoários/isolamento & purificação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
Introduction: Despite efforts to control malaria, around 10% of the world population is at risk of acquiring this disease. Plasmodium falciparum accounts for the majority of severe cases and deaths. Malaria control programs have failed due to the therapeutic failure of first-line antimalarials and to parasite resistance. Thus, new and better therapeutic alternatives are required. Proteomic analysis allows determination of protein expression levels under drug pressure, leading to the identification of new therapeutic drug targets and their mechanisms of action. Objective: The aim of this study was to analyze qualitatively the expression of P.falciparum trophozoite proteins (strain ITG2), after exposure to antimalarial drugs, through a proteomic approach. Materials and methods: In vitro cultured synchronized parasites were treated with quinine, mefloquine and the natural antiplasmodial diosgenone. Protein extracts were prepared and analyzed by two-dimensional electrophoresis. The differentially expressed proteins were selected and identified by MALDI-TOF mass spectrometry. Results: The following proteins were identified among those differentially expressed in the parasite in the presence of the drugs tested: enolase (PF10_0155), calcium-binding protein (PF11_0098), chaperonin (PFL0740c), the host cell invasion protein (PF10_0268) and proteins related to redox processes (MAL8P1.17). These findings are consistent with results of previous studies where the parasite was submitted to pressure with other antimalarial drugs. Conclusion: The observed changes in the P. falciparum trophozoite protein profile induced by antimalarial drugs involved proteins mainly related to the general stress response.
Introducción. A pesar de los esfuerzos para controlar la malaria, esta sigue siendo un problema de salud pública. Plasmodium falciparum es responsable de la mayoría de los casos graves y de las muertes. Los programas de control de la malaria han sido cuestionados debido al fracaso del tratamiento y a la resistencia del parásito a los antipalúdicos de primera línea, por lo que se requieren nuevas y mejores alternativas. El análisis proteómico permite identificar y determinar los niveles de expresión de las proteínas bajo la presión de los medicamentos, lo que posibilita la identificación de nuevos blancos terapéuticos y mecanismos de acción. Objetivo. Analizar cualitativamente la expresión diferencial de proteínas del citosol del trofozoíto de P. falciparum bajo tratamiento con quinina, mefloquina y el compuesto natural diosgenona mediante una aproximación proteómica. Materiales y métodos. Se trataron trofozoítos sincronizados y cultivados in vitro de P. falciparum (cepa ITG2) con quinina, mefloquina y el compuesto natural diosgenona. Los extractos proteicos se prepararon y analizaron por electroforesis bidimensional. Las proteínas con aparente expresión diferencial se seleccionaron e identificaron mediante espectrometría de masas MALDI-TOF. Resultados. Se encontraron las siguientes proteínas diferencialmente expresadas en el trofozoíto: la enolasa (PF10_0155), la proteína de unión a calcio (PF11_0098), la chaperonina (PFL0740c), la proteína de invasión a la célula del huésped (PF10_0268) y la proteína relacionada con procesos de reducción y oxidación (redox) (MAL8P1.17). Estos hallazgos son congruentes con resultados previos de estudios en los que el parásito fue presionado con otros medicamentos antipalúdicos. Conclusión. Los cambios observados en el perfil de proteínas del trofozoíto de P. falciparum tratado con antipalúdicos involucraron preferencialmente proteínas relacionadas con la respuesta al estrés general.
Assuntos
Humanos , Antiprotozoários/farmacologia , Mefloquina/farmacologia , Plasmodium falciparum/efeitos dos fármacos , Proteínas de Protozoários/biossíntese , Quinina/farmacologia , Compostos de Espiro/farmacologia , Triterpenos/farmacologia , Sequência de Aminoácidos , Eletroforese em Gel Bidimensional , Eritrócitos/parasitologia , Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas de Choque Térmico/biossíntese , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/isolamento & purificação , Técnicas In Vitro , Dados de Sequência Molecular , Proteoma , Plasmodium falciparum/crescimento & desenvolvimento , Plasmodium falciparum/metabolismo , Proteínas de Protozoários/genética , Proteínas de Protozoários/isolamento & purificação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
This article addresses the discussion about quinine-resistant malaria plasmodium in the early decades of the twentieth century. Observed by Arthur Neiva in Rio de Janeiro in 1907, the biological and social resistance of malaria sufferers to preventive and curative treatment with quinine was corroborated three years later by Oswaldo Cruz during the construction of the Madeira-Mamoré Railway in the Brazilian Amazon. Likewise in 1910, ailing German workers were transferred from Brazil to Hamburg's Institute for Maritime and Tropical Diseases, where quinine resistance was confirmed by Bernard Nocht and Heinrich Werner. When the First World War saw failures in treating and preventing malaria with quinine along with violent outbreaks of the disease on the Turkish and Balkan fronts, resistance to this alkaloid became the topic of the day within the field of experimental medicine in Germany. New attempts were made to account for the resistance, especially by the physician Ernst Rodenwaldt, who explored the topic by applying modern theories on heredity. The present article offers a preliminary survey and analysis of pronouncements about quinine resistance, shedding new light on the circulation of knowledge in the field of tropical medicine.
Assuntos
Antimaláricos/história , Resistência a Medicamentos , Malária/história , Quinina/história , Antimaláricos/farmacologia , Antimaláricos/uso terapêutico , Brasil , Alemanha , História do Século XX , Humanos , Malária/tratamento farmacológico , Plasmodium/efeitos dos fármacos , Quinina/farmacologia , Quinina/uso terapêutico , Medicina Tropical/históriaRESUMO
Plants belonging to the genus Cinchona L. (Rubiaceae), whose active ingredient is quinine, was used for centuries to treat malaria. Plants of this genus are a potential source of new structural templates in the search for new antimalarial candidates. This study aimed to the identification, quantification of quinine and other metabolites present in extracts of different polarity of the stems of Cinchona pubescens Vahl. , oxoquinovic acid isolation, antiplasmodial activity, and measuring its cytotoxic effect. The results show a high activity to antiplasmodial alkaloids extract (IC50 = 2.20 +/- 0.0325 ug/mL), cytotoxicity (CC50 = 80.2 +/- 12.2 ug/mL), and a quinine content of 21.3+/-0.0247 ppm. The compound known as acid antiplasmodial activity oxoquinovic presented in IC50 = 11.3 +/- 0.741 ug/mL, and cytotoxicity CC50 = 72.4 +/- 3.85 ug/mL. These results motivate phytochemical studies in the search for active structural analogues quinine and quinolinic core as a source of new antimalarial agents.
Las plantas pertenecientes al género Cinchona L. (familia Rubiaceae), cuyo principio activo es la quinina, fueron utilizadas durante siglos para tratar la malaria. Este género es una fuente potencial de nuevas plantillas estructurales en la búsqueda de nuevos candidatos antimaláricos. El presente trabajo tuvo como objetivo la identificación y, cuantificación de la quinina y de otros metabolitos presentes en los extractos de diferente polaridad, de los tallos de Cinchona pubescens Vahl. , el aislamiento del ácido oxoquinóvico, la actividad antiplasmodial y, además, la medición de su efecto citotóxico. Los resultados muestran una alta actividad antiplasmodial para el extracto de los alcaloides (IC50 = 2,20 +/- 0,0325 ug/mL), una baja citotoxicidad (CC50 = 80,2 +/- 12,2 ug/mL), y un alto contenido de quinina el cual fue 21,3+/-0,0247 ppm. El compuesto ácido oxoquinóvico presentó una actividad antiplasmodial de IC50 = 11,3 +/- 0.741 ug/mL, y una citotoxicidad de CC50 = 72,4 +/- 3,85 ug/mL. Estos resultados motivan los estudios fitoquímicos en la búsqueda de principios activos y análogos estructurales en diferentes especies de Cinchonas como una fuente de nuevos agentes antimaláricos.
Assuntos
Antimaláricos/química , Cinchona/química , Extratos Vegetais/química , Quinina/isolamento & purificação , Quinina/farmacologia , Alcaloides/farmacologia , Antimaláricos/farmacologia , Cromatografia Líquida de Alta Pressão , Extratos Vegetais/farmacologia , Plasmodium falciparum , Quinina/química , Testes de Toxicidade , Caules de Planta/químicaRESUMO
Artemisinin is the active antimalarial compound obtained from the leaves of Artemisia annua L. Artemisinin, and its semi-synthetic derivatives, are the main drugs used to treat multi-drug-resistant Plasmodium falciparum (one of the human malaria parasite species). The in vitro susceptibility of P. falciparum K1 and 3d7 strains and field isolates from the state of Amazonas, Brazil, to A. annua infusions (5 g dry leaves in 1 L of boiling water) and the drug standards chloroquine, quinine and artemisinin were evaluated. The A. annua used was cultivated in three Amazon ecosystems (várzea, terra preta de índio and terra firme) and in the city of Paulínia, state of São Paulo, Brazil. Artemisinin levels in the A. annua leaves used were 0.90-1.13% (m/m). The concentration of artemisinin in the infusions was 40-46 mg/L. Field P. falciparum isolates were resistant to chloroquine and sensitive to quinine and artemisinin. The average 50% inhibition concentration values for A. annua infusions against field isolates were 0.11-0.14 µL/mL (these infusions exhibited artemisinin concentrations of 4.7-5.6 ng/mL) and were active in vitro against P. falciparum due to their artemisinin concentration. No synergistic effect was observed for artemisinin in the infusions.
Assuntos
Antimaláricos/farmacologia , Artemisia annua/química , Extratos Vegetais/farmacologia , Plasmodium falciparum/efeitos dos fármacos , Artemisininas/farmacologia , Brasil , Cloroquina/farmacologia , Sinergismo Farmacológico , Concentração Inibidora 50 , Testes de Sensibilidade Parasitária/métodos , Quinina/farmacologiaRESUMO
Artemisinin is the active antimalarial compound obtained from the leaves of Artemisia annua L. Artemisinin, and its semi-synthetic derivatives, are the main drugs used to treat multi-drug-resistant Plasmodium falciparum (one of the human malaria parasite species). The in vitro susceptibility of P. falciparum K1 and 3d7 strains and field isolates from the state of Amazonas, Brazil, to A. annua infusions (5 g dry leaves in 1 L of boiling water) and the drug standards chloroquine, quinine and artemisinin were evaluated. The A. annua used was cultivated in three Amazon ecosystems (várzea, terra preta de índio and terra firme) and in the city of Paulínia, state of São Paulo, Brazil. Artemisinin levels in the A. annua leaves used were 0.90-1.13% (m/m). The concentration of artemisinin in the infusions was 40-46 mg/L. Field P. falciparum isolates were resistant to chloroquine and sensitive to quinine and artemisinin. The average 50% inhibition concentration values for A. annua infusions against field isolates were 0.11-0.14 μL/mL (these infusions exhibited artemisinin concentrations of 4.7-5.6 ng/mL) and were active in vitro against P. falciparum due to their artemisinin concentration. No synergistic effect was observed for artemisinin in the infusions.
Assuntos
Antimaláricos/farmacologia , Artemisia annua/química , Extratos Vegetais/farmacologia , Plasmodium falciparum/efeitos dos fármacos , Artemisininas/farmacologia , Brasil , Cloroquina/farmacologia , Sinergismo Farmacológico , Testes de Sensibilidade Parasitária/métodos , Quinina/farmacologiaRESUMO
BACKGROUND: In animal models of continuous alcohol self-administration, in which physical dependence does not constitute the major factor of ethanol intake, 2 factors likely contribute to the perpetuation of alcohol self-administration: (i) the rewarding effects of ethanol and (ii) the contextual conditioning cues that exist along with the process of self-administration. Present studies are aimed at understanding the relative contribution of these factors on the perpetuation of heavy alcohol self-administration, as an indication of relapse. METHODS: Wistar-derived UChB high ethanol drinker rats were allowed access to 10% ethanol and water on a 24-hour basis. In initial studies, an anticatalase shRNA gene-coding lentiviral vector aimed at inhibiting acetaldehyde generation was administered into the ventral tegmental area (VTA) of the animals prior to ethanol access. In subsequent studies, the lentiviral vector was administered to animals, which had consumed ethanol on a 24-hour basis, or a 1-hour basis, after the animals had reached high levels of ethanol intake for 60 to 80 days. In final studies, quinine (0.01%) was added to the ethanol solution to alter the conditioning taste/smell cues of alcohol that animals had chronically ingested. RESULTS: Data indicate that the administration of an anticatalase vector into the VTA of naïve animals blocked reward and alcohol self-administration, while it was, nevertheless, inactive in inhibiting alcohol self-administration in rats that had been conditioned to ingest ethanol for over 2 months. The lack of inhibitory effect of the anticatalase vector on ethanol intake in animals that had chronically self-administered ethanol was fully reversed when the contextual conditioning cues of the alcohol solution were changed. CONCLUSIONS: Data highlight the importance of conditioning factors in relapse and suggest that only abolishing or blunting it, along with long-lasting pharmacological treatment to reduce ethanol reward, may have protracted effects in reducing alcohol self-administration.
Assuntos
Consumo de Bebidas Alcoólicas/psicologia , Alcoolismo/prevenção & controle , Alcoolismo/terapia , Recompensa , Acetaldeído/metabolismo , Consumo de Bebidas Alcoólicas/metabolismo , Consumo de Bebidas Alcoólicas/terapia , Alcoolismo/genética , Alcoolismo/metabolismo , Animais , Catalase/antagonistas & inibidores , Catalase/genética , Sinais (Psicologia) , Modelos Animais de Doenças , Etanol/administração & dosagem , Etanol/antagonistas & inibidores , Etanol/farmacologia , Vetores Genéticos/administração & dosagem , Humanos , Lentivirus/genética , Microinjeções , Quinina/farmacologia , RNA Interferente Pequeno/administração & dosagem , RNA Interferente Pequeno/uso terapêutico , Ratos , Ratos Wistar , Prevenção Secundária , Autoadministração , Área Tegmentar Ventral/efeitos dos fármacos , Área Tegmentar Ventral/metabolismoAssuntos
Antimaláricos/farmacologia , Antimaláricos/uso terapêutico , Malária Falciparum/tratamento farmacológico , Plasmodium falciparum/efeitos dos fármacos , Quinina/farmacologia , Quinina/uso terapêutico , Adulto , Doxiciclina/farmacologia , Doxiciclina/uso terapêutico , Resistência a Medicamentos/efeitos dos fármacos , Resistência a Medicamentos/genética , França , Guiana Francesa , Humanos , Malária Falciparum/diagnóstico , Masculino , Proteínas de Membrana Transportadoras/genética , Mutação/genética , Plasmodium falciparum/genética , Plasmodium falciparum/isolamento & purificação , Mutação Puntual , Polimorfismo Genético/genética , Proteínas de Protozoários/genética , Falha de TratamentoRESUMO
The effect of 16 alpha-acetoxy-26-hydroxycholest-4-ene-3,22-dione (SN-1) isolated from Solanum nudum Dunal (a Solanaceae traditionally used for treating fever in Colombia) on Plasmodium falciparum erythrocyte stages and its in vitro antiplasmodial activity when combined with the following conventional drugs was studied: chloroquine (CQ), amodiaquine (AQ), desethylamodiaquine (desethyl-AQ), quinine (QN), artemisinin (AR), atovaquone (ATV) and quinine (QN). It was found that SN-1 targeted trophozoites and had a synergistic effect when combined with CQ and QN; however, it had an antagonist effect when used with the other combinations.