Anthelmintics used for intestinal helminthiasis treatment are generally effective; however, their effectiveness in tissue parasitosis (i.e. visceral toxocariasis) is moderate. The aim of this study was to evaluate the in vitroactivity of lapachol, β-lapachone and phenazines in relation to the viability of Toxocara canis larvae. A concentration of 2 mg/mL (in duplicate) of the compounds was tested using microculture plates containing Toxocara canis larvae in an RPMI-1640 environment, incubated at 37 °C in 5% CO2 tension for 48 hours. In the 2 mg/mL concentration, four phenazines, lapachol and three of its derivatives presented a larvicide/larvistatic activity of 100%. Then, the minimum larvicide/larvistatic concentration (MLC) test was conducted. The compounds that presented the best results were nor-lapachol (MLC, 1 mg/mL), lapachol (MLC 0.5 mg/mL), β-lapachone, and β-C-allyl-lawsone (MLC, 0.25 mg/mL). The larvae exposed to the compounds, at best MLC with 100% in vitro activity larvicide, were inoculated into healthy BALB/c mice and were not capable of causing infection, confirming the larvicide potential in vitro of these compounds.
RESUMO Justificativa e objetivos:A vasta biodiversidade amazônica tem sido apontada como uma fonte de produtos naturais candidatos a diversas atividades farmacológicas, principalmente no combate a doenças infecciosas. Algumas espécies, tais como as pertencentes ao gênero Duroia, da família Rubiaceae, têm sido caracterizadas pela produção de metabólitos secundários com propriedades biológicas importantes, porém são escassos os estudos com espécies deste gênero. Desta forma, o objetivo deste estudo foi avaliar a atividade antimicobacteriana, antifúngica e antiparasitária de extratos de D. macrophylla e D. saccifera. Métodos: Foram coletados materiais vegetais de D. macrophylla e D. saccifera na Reserva Florestal A. Ducke em Manaus-AM, a partir dos quais foram preparados extratos diclorometânico, metanólico e aquoso e determinada a concentração inibitória e concentração larvicida mínima. Resultados: No que diz respeito aos extratos de D. saccifera¸ o extrato diclorometânico dos galhos foi o mais ativo frente às espécies fúngicas e as cepas micobacterianas avaliadas. Por outro lado, o extrato metanólico e o diclorometânico das folhas de D. macrophylla, foram os mais ativos frente a Candida sp. e Mycobacterium tuberculosis, respectivamente, porém, nenhum dos seis extratos avaliados apresentaram atividade antiparasitária frente a Toxocara canis. Conclusão: Esses resultados demonstram as propriedades antimicrobianas dessas plantas amazônicas para o desenvolvimento de novas alternativas terapêuticas no tratamento de doenças infecciosas, tais como a tuberculose e candidíase. DESCRITORES: Candida. Rubiaceae. Mycobacterium tuberculosis. Toxocara canis. ABSTRACT Bachground and objective:The wide Amazonian biodiversity has been identified as a source of natural product candidates to various pharmacological activities, particularly in combating infectious diseases. Some species, such as the genus Duroia, belonging to the Rubiaceae family, has been characterized by the production of secondary metabolites with important biological properties, but there are few studies with species of this genus. Thus, the objective of this study was to evaluate the antimycobacterial, antifungal and antiparasitic activity of D. macrophylla and D. saccifera extracts by determining the minimum inhibitory concentration and minimum larvicide concentration. Methods: Were collected plant materials of the D. macrophylla and D. saccifera in Forest Reserve A. Ducke in Manaus AM, from which were prepared dichloromethane, methanol and aqueous extracts and determined the minimum inhibitory concentration and larvicidal concentration. Results: With regard to D. saccifera¸ extracts the dichloromethane extract of the branches was the most active against the fungal species and mycobacterial strains evaluated. On the other hand, the methanol and dichloromethane extract of the D. macrophylla leaves, were most active against Candida sp. and Mycobacterium tuberculosis, respectively, but none of the six evaluated extracts showed antiparasitic activity against Toxocar...
Human toxocarosis is a chronic tissue parasitosis most often caused by Toxocara canis. The seroprevalence can reach up to 50%, especially among children and adolescents. The anthelmintics used in the treatment have moderate efficacy. The aim of this study was to evaluate the in vitro and in vivo anthelmintic activity of quinones and their derivatives against T. canis larvae and the cytotoxicity of the larvicidal compounds. The compounds were evaluated at 1 mg mL(-1) concentration in microculture plates containing third stage larvae in an Roswell Park Memorial Institute (RPMI) 1640 environment, incubated at 37 °C in 5% CO2 tension for 48 h. Five naphthoxiranes were selected for the cytotoxicity analysis. The cell viability evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and lactate dehydrogenase assays using murine peritoneal macrophages isolated from C57BL/6 mice revealed that the naphthoxiranes (1 and 3) were less cytotoxic at a concentration of 0.05 mg mL(-1). The efficacy of naphthoxiranes (1 and 3) was examined in murine toxocarosis also. The anthelmintic activity was examined by evaluating the number of larvae in the brain, carcass, liver, lungs, heart, kidneys and eyes. Compound (3) demonstrated anthelmintic activity similar to that of albendazole by decreasing the number of larvae in the organs of mice and thus could form the basis of the development of a new anthelmintic drug.
Prevalência de enteroparasitas em crianças atendidas em unidades básicas de saúde em uma cidade do sul do BrasilPrevalence of enteroparasites in children attended at basic health unities in a Brazilian southern city RESUMOAs helmintoses e protozooses intestinais constituem sério problema de saúde pública nos países em desenvolvimento. Este estudo analisou a prevalência de parasitas intestinais em crianças pré-escolares atendidas em Unidades Básicas de Saúde (UBS) na cidade do Rio Grande, Rio Grande do Sul, Brasil. Foram examinadas amostras de fezes de 144 crianças, no período de outubro de 2009 a março de 2010. A prevalência de parasitas patogênicos foi de 17,4 %, em que foram detectados ovos dos nematoides Ascaris lumbricoides (11,1 %) e Trichuris trichiura (6,3 %), e cistos do protozoário Giardia lamblia (4,9 %). Foram também identificados cistos de protozoários considerados não patogênicos, como Entamoeba coli, Endolimax nana e Enteromonas hominis, em 28,5 % das crianças. Em relação às prevalências nas UBS, as positividades foram de 36,4 % na UBS-1, 11,1 % na UBS-3, 14,8 % na UBS-4, 8 % na UBS-5 e 19,2 % na UBS-6. Na UBS-2 não foi detectada positividade nas amostras de fezes analisadas. A prevalência de parasitas patogênicos registrada na população estudada sugere a ocorrência de prováveis condições de reinfecção e a necessidade de implementar medidas de saneamento básico e de programas que possibilitem a melhoria da condição de vida dessas crianças. Palavras-chave. parasitas intestinais, pré-escolar, saúde pública. ABSTRACTHelminthes and enteric protozoa are serious problem of public health in developing countries. This study analyzed the prevalence of intestinal parasites in preschool children attend at basic health unities (BHS) in the city of Rio Grande, Rio Grande do Sul, Brazil. Stool samples collected from 144 children were analyzed, from October 2009 to March 2010. The observed prevalence rate for enteroparasites was 17.4 %, including eggs of nematodes Ascaris lumbricoides (11.1 %) and Trichuris trichiura (6.3 %), and cysts of protozoan Giardia lamblia (4.9 %). Also, cysts of protozoa considered as non-pathogenic, such as Entamoeba coli, Endolimax nana and Enteromonas hominis were found in 28.5 % of children. Regarding to the BHSs prevalence, in BHS-1 was detected a positivity of 36.4 %, 11.1 % in BHS-3, 14.8 % in BHS-4, 8 % in BHS-5 and 19.2 % in BHS-6. No positivity was detected in the stool samples from BHS-2. The prevalence of intestinal parasites registered in the studied population suggests the occurrence of probable conditions for re-infection, and the need to implement the basic sanitation procedures and programs which will provide an improvement in the life quality of these children.
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