Avaliação in vitro e in vivo da atividade antiplasmodial e citotoxicidade de novos compostos derivados de 4- aminoquinolinas

With the emergence of resistant strains of Plasmodium the new therapeutic strategies are necessary for malaria control. The use of the hybridized 4- aminoquinoline ring with different chemical groups has been shown to be a promising technique to obtain benefits from activity, even in the presence of resistant strains. The objective this study was to evaluate new candidates for antimalarial drugs by the analysis of physicochemical, pharmacokinetic and molecular docking in silico, cytotoxicity, mechanism of action in vitro and antiplasmodial activity (in vitro and in vivo). Two groups of molecules were synthesized from the 4-aminoquinoline ring and conjugated to different aromatic groups. The first group, designated H, has a hydrazone attached to the 4-aminoquinoline ring, and the second group, designated I, it has an imine group as the substituent, both having biological properties. Physical- chemical properties and docking were analyzed using computational tools. Cytotoxicity parameters were evaluated in human erythrocytes, VERO - kidney epithelial cells and WI26VA4 human fibroblasts. The antiplasmodial activity against P. falciparum W2 was performed by the HRPII-ELISA technique. Possible alterations in the digestive vacuole of the parasite were observed by confocal microscopy. Finally, in vivo antimalarial activity was determined by the Peters suppressive test, performed on P. berghei NK65 infected mice and treated with the derivatives. Most of all, in silico data showed that the molecules had good physicochemical and pharmacokinetic prediction, they are non-carcinogenic and no classified in category III acute oral toxicity. In the hemolysis test, it was found that no derivative promoted more than 10% cell lysis. In addition, the derivatives showed low cytotoxicity, and were selective to the parasites. The in vitro evaluation of the molecules influence on the vacuole pH showed that I6 and I7 promoted an increase in the internal pH of the organelle that coincided with the pharmacological effects of artesunate, which is standard drug. In relation to the in vivo activity, I6 and I7 obtained important values of IMP on the 5th day after infection (I6 15 mg/kg = 72.64% and I7 15 mg/kg = 71.15% and 25 mg/kg = 93,7%). In the 9th d.p.i there was reduction in the activity of both derivatives, but I7 maintained its activity. It was observed that the synthesis process of the series of 4-aminoquinoline derivatives of this study was promising, especially in group I, producing molecules with antiplasmodial activity.om o surgimento de cepas resistentes de Plasmodium, novas estratégias terapêuticas são necessárias para o controle da malária. A utilização do anel 4- aminoquinolínico hibridizado a diferentes grupos químicos demonstrou ser uma técnica promissora para obter derivados com atividade, mesmo na presença de cepas resistentes. O objetivo deste trabalho foi avaliar novos candidados a fármacos antimaláricos pela análise de propriedades fisico-quimicas, farmacocinéticas e docking molecular in silico, avaliação da citototoxicidade, mecanismo de ação in vitro e atividade antiplasmodial (in vitro e in vivo). Dois grupos de moléculas foram sintetizados a partir do anel 4-aminoquinolínico e conjugados a diferentes grupos aromáticos. O primeiro grupo, denominado H, apresenta uma hidrazona ligado ao anel 4 aminoquinolínico e o segundo grupo, denominado I, apresenta um grupo imina como substituinte, ambas com propriedades biológicas. As propriedades físico-químicas e o docking foram analisados por meio de ferramentas computacionais. Os parâmetros de citotoxicidade foram avaliados em eritrócitos humanos, células epiteliais de rim de macaco (VERO) e fibroblastos de pulmão humano (WI26VA4). A atividade antiplasmodial contra P. falciparum W2 foi realizada pela técnica de ELISA-HRPII. Possíveis alterações no vacúolo digestivo do parasito foram observadas por microscopia confocal. Finalmente, a atividade antimalárica in vivo foi determinada pelo teste supressivo de Peters, realizado em camundongos infectados com P. berghei NK65 e tratados com os candidatos à farmacos. Em geral, os dados in silico mostraram que as moléculas apresentaram boa predição físico- química e farmacocinética, não são carcinogênicas e são classificadas na categoria III de toxicidade aguda oral. No teste de hemólise verificou-se que nenhum candidato à farmaco promoveu mais de 10% de lise das células. Ademais, os derivados apresentaram baixa citotoxicidade, e foram seletivos aos parasitos. A avaliação in vitro da influência das moleculas no pH do vacúolo permitiu observar que I6 e I7 promovem aumento do pH interno da organela, o que coincidiu com os efeitos farmacológicos observados com a adição de drogas padrão, como o artesunato. Em relação à atividade in vivo, o tratamento com I6 e I7 resultou em valores importantes de IMP no 5º dia após a infecção (I6 15 mg/kg = 72,64% e I7 15 mg/kg = 71,15% e 25 mg/kg = 93,7%) . No 9º d.p.i houve redução na atividade de ambos derivados, porém I7 ainda apresentava ativo. O processo de síntese da série de derivados 4-aminoquinolínicos deste estudo foi promissor, especialmente no grupo I, produzindo moléculas com atividade antiplasmodial.FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerai

Análise da função fagocítica de macrófagos de animais infectados com Plasmodium berghei NK65

Malaria is a major tropical disease with worldwide distribution. The disease is caused by protozoa of the genus Plasmodium which infects humans and other animal species. Experimental models of infection by Plasmodium berghei NK65A (PbBNK65A) in Balb/c mice is important in the understanding of human disease. Immune response to malaria configures itself extremely, involving different elements. Macrophages are important cells against the erythrocytic parasite stage. Thus, the study aimed to evaluate different aspects of macrophage functions during infection by PbNK65A. The results showed that the parasite does not alter the frequency on peritoneal macrophages. However, the infected animals showed higher expression of coestimulatory molecules, mainly CD80 and significant reduction in the ability to phagocytosis infected erythrocytes during the infection. The production of IL-12 cytokine, important for activation of the cellular response, was also affected during infection. Thus, we suggest that infection by Plasmodium affects the innate immune response, and this can be attributed to the negative character of the infection on the macrophages, which has changed its principal functions, such as phagocytosis and IL-12 production. Although co-stimulation is preserved and even higher in this model, is insufficient to generate a host cell response that limits the proliferation of Plasmodium, and especially the host death.A malária é uma importante doença tropical com distribuição mundial. A doença é causada por protozoários do gênero Plasmodium que infectam humanos e outras espécies animais. Modelos experimentais de infecção por Plasmodium berghei NK65A (PbNK65A) em camundongos Balb/c auxiliam na compreensão da doença humana. A resposta imune à malária é extremamente complexa. Os macrófagos apresentam-se como importantes células no combate ao estágio eritrocítico do parasito. O trabalho buscou avaliar diferentes aspectos da função destas células durante a infecção por PbNK65. Os resultados demonstraram que a parasitose não altera a frequência relativa da população de macrófagos peritoneais nos camundongos. Porém, os animais infectados, apresentaram maior expressão de moléculas co-estimuladoras, principalmente CD80, e expressiva redução da capacidade de fagocitar hemácias parasitadas ao longo da infecção. A produção da IL-12, citocina importante para ativação da resposta celular também foi intensamente prejudicada pelo parasito no decorrer da infecção. Diante dos resultados, podemos sugerir que a infecção por Plasmodium berghei NK65 interfere na resposta imune inata, e esta pode ser atribuída ao caráter negativo da infecção sobre o macrófago, que possui suas principais funções alteradas, como a fagocitose e a produção de IL-12. Ainda que a co-estimulação seja preservada e até elevada neste modelo, é insuficiente para o hospedeiro gerar uma resposta celular eficiente que limitaria a proliferação de Plasmodium e, sobretudo, a morte do hospedeiro.CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

Improvement of antimalarial activity of a 3-alkylpiridine alkaloid analog by replacing the pyridine ring to a thiazole-containing heterocycle : mode of action, mutagenicity profile, and Caco-2 cell-based permeability.

The development of new antimalarial drugs is urgent to overcome the spread of resistance to the current treatment. Herein we synthesized the compound 3, a hit-to?lead optimization of a thiazole based on the most promising 3-alkylpyridine marine alkaloid analog. Compound 3 was tested against Plasmodium falciparum and has shown to be more potent than its precursor (IC50 values of 1.55 and 14.7??M, respectively), with higher selectivity index (74.7) for noncancerous human cell line. This compound was not mutagenic and showed genotoxicity only at concentrations four-fold higher than its IC50. Compound 3 was tested in vivo against Plasmodium berghei NK65 strain and inhibited the development of parasite at 50?mg/kg. In silico and UV?vis approaches determined that compound 3 acts impairing hemozoin crystallization and confocal microscopy experiments corroborate these findings as the compound was capable of diminishing food vacuole acidity. The assay of uptake using human intestinal Caco-2 cell line showed that compound 3 is absorbed similarly to chloroquine, a standard antimalarial agent. Therefore, we present here compound 3 as a potent new lead antimalarial compound

NEOTROPICAL CARNIVORES: a data set on carnivore distribution in the Neotropics

Mammalian carnivores are considered a key group in maintaining ecological health and can indicate potential ecological integrity in landscapes where they occur. Carnivores also hold high conservation value and their habitat requirements can guide management and conservation plans. The order Carnivora has 84 species from 8 families in the Neotropical region: Canidae; Felidae; Mephitidae; Mustelidae; Otariidae; Phocidae; Procyonidae; and Ursidae. Herein, we include published and unpublished data on native terrestrial Neotropical carnivores (Canidae; Felidae; Mephitidae; Mustelidae; Procyonidae; and Ursidae). NEOTROPICAL CARNIVORES is a publicly available data set that includes 99,605 data entries from 35,511 unique georeferenced coordinates. Detection/non-detection and quantitative data were obtained from 1818 to 2018 by researchers, governmental agencies, non-governmental organizations, and private consultants. Data were collected using several methods including camera trapping, museum collections, roadkill, line transect, and opportunistic records. Literature (peer-reviewed and grey literature) from Portuguese, Spanish and English were incorporated in this compilation. Most of the data set consists of detection data entries (n = 79,343; 79.7%) but also includes non-detection data (n = 20,262; 20.3%). Of those, 43.3% also include count data (n = 43,151). The information available in NEOTROPICAL CARNIVORES will contribute to macroecological, ecological, and conservation questions in multiple spatio-temporal perspectives. As carnivores play key roles in trophic interactions, a better understanding of their distribution and habitat requirements are essential to establish conservation management plans and safeguard the future ecological health of Neotropical ecosystems. Our data paper, combined with other large-scale data sets, has great potential to clarify species distribution and related ecological processes within the Neotropics. There are no copyright restrictions and no restriction for using data from this data paper, as long as the data paper is cited as the source of the information used. We also request that users inform us of how they intend to use the data

NEOTROPICAL ALIEN MAMMALS: a data set of occurrence and abundance of alien mammals in the Neotropics

Biological invasion is one of the main threats to native biodiversity. For a species to become invasive, it must be voluntarily or involuntarily introduced by humans into a nonnative habitat. Mammals were among first taxa to be introduced worldwide for game, meat, and labor, yet the number of species introduced in the Neotropics remains unknown. In this data set, we make available occurrence and abundance data on mammal species that (1) transposed a geographical barrier and (2) were voluntarily or involuntarily introduced by humans into the Neotropics. Our data set is composed of 73,738 historical and current georeferenced records on alien mammal species of which around 96% correspond to occurrence data on 77 species belonging to eight orders and 26 families. Data cover 26 continental countries in the Neotropics, ranging from Mexico and its frontier regions (southern Florida and coastal-central Florida in the southeast United States) to Argentina, Paraguay, Chile, and Uruguay, and the 13 countries of Caribbean islands. Our data set also includes neotropical species (e.g., Callithrix sp., Myocastor coypus, Nasua nasua) considered alien in particular areas of Neotropics. The most numerous species in terms of records are from Bos sp. (n = 37,782), Sus scrofa (n = 6,730), and Canis familiaris (n = 10,084); 17 species were represented by only one record (e.g., Syncerus caffer, Cervus timorensis, Cervus unicolor, Canis latrans). Primates have the highest number of species in the data set (n = 20 species), partly because of uncertainties regarding taxonomic identification of the genera Callithrix, which includes the species Callithrix aurita, Callithrix flaviceps, Callithrix geoffroyi, Callithrix jacchus, Callithrix kuhlii, Callithrix penicillata, and their hybrids. This unique data set will be a valuable source of information on invasion risk assessments, biodiversity redistribution and conservation-related research. There are no copyright restrictions. Please cite this data paper when using the data in publications. We also request that researchers and teachers inform us on how they are using the data