The prophylactic and therapeutic arsenal against malaria is quite restricted and all the antimalarials currently in use have limitations. Thus, there is a need to investigate medicinal plants in the search for phytochemicals which can be developed into drugs. In our investigation, essential oils (EOs) were obtained from Vanillosmopsis arborea (Gardner) Baker, Lippia sidoides Cham. and Croton zehntneri Pax & K. Hoffm., aromatic plants abundant in northeastern Brazil, which are found in the caatinga region and are used in traditional medicine. The chemical composition of these EOs was characterized by GC-MS, and monoterpenes and sesquiterpenes were well represented. We assessed the in vitro activity of these EOs and also individual EO chemical components against the human malaria parasite Plasmodium falciparum (K1 strain) and the in vivo activity of EOs in mice infected with Plasmodium berghei. The acute toxicity of these oils was assessed in healthy mice and in vitro cytotoxicity was determined at different concentrations against HeLa cells and mice macrophages. The EO of V. Arborea was partially active only when using the subcutaneous route (inhibited from 33 up to 47 %). In relation to the EOs, L. sidoides and C. zehntneri were active only by the oral route (per gavage) and partially inhibited the growth of P. berghei from 43 up to 55 % and showed good activity against P. falciparum in vitro (IC (50) = 7.00, 10.50, and 15.20 µg/mL, respectively). Individual EO constituents α-bisabolol, estragole, and thymol also exhibited good activity against P. falciparum (IC (50) = 5.00, 30.70, and 4.50 µg/mL, respectively). This is the first study showing evidence for the antimalarial activity of these species from northeastern Brazil and the low toxicity of their EOs.
RESUMO:Tendo em vista que bactérias resistentes a antimicrobianos representam um desafi o no tratamento de infecções, é notória a necessidade de encontrar novas substâncias com propriedades antimicrobianas para serem utilizadas no combate a esses microrganismos. Este trabalho relata a avaliação da atividade antibacteriana, toxicidade e identifi cação dos componentes químicos do óleo essencial de Croton zehntneri (variedade estragol), planta utilizada na medicina popular como calmante e estimulante do apetite. A atividade antimicrobiana e a concentração inibitória mínima (CIM) foram determinadas pelo método de difusão em discos. A avaliação da toxicidade foi realizada frente à Artemia salina com resultado considerado ativo (CL 50 < 100 μg/mL). O óleo essencial das folhas apresentou atividade antibacteriana frente a todas as bactérias testadas exceto contra Salmonella typhimurium, sendo o melhor resultado frente a Shigella fl exneri com CIM de 50 μg/mL. A análise da composição química foi obtida por cromatografi a gasosa acoplada a espectrometria de massa (CG/EM) e permitiu identifi car um total de 97,4% dos componentes, com presença majoritária de estragol (76,8%). A presença de tal constituinte nos impulsiona a realização de estudos com outras bactérias, já que o estragol foi anteriormente relatado como sendo responsável por atividades antibacterianas. Unitermos:Croton zehntneri, Euphorbiaceae, estragol, óleo essencial, atividade antibacteriana, toxicidade, CIM.ABSTRACT: "Chemical composition and evaluation of the antibacterial activity and toxicity of the essential oil of Croton zehntneri (variety estragol)". Observing that bacteria resistant to antimicrobials represent a challenge in the treatment of infections, it is notorious the need of fi nding new substances with antimicrobial features to be used in the fi ght against these microorganisms. This work relates the evaluation of the antibacterial activity, toxicity and identifi cation of the chemical components of the essential oil of Croton zehntneri (variety estragol), plant used in the popular medicine as tranquilizer and appetite stimulant. The antimicrobial activity and minimum inhibitory concentration (MIC) were determined by the method of diffusion in discs. The evaluation of the toxicity was held through brine shrimp test with results considered active (LC 50 < 100 μg/mL). The essential oil of leaves presented antibacterial activity with all the bacteria tested except with Salmonlla typhimurium, being the best result with the Shigella fl exneri with MIC of 50 μg/mL. The analysis of the chemical composition was obtained by gas chromatography coupled to mass spectrometry (GC/MS) and permitted to identify a total of 97.4 % of the components, with major presence of estragol (76.8%). The presence of the latter drives us to studies with other bacteria, as the estragol was previously reported as being responsible for antibacterial activities.
"Chemical-biological study of the essential oils of Hyptis martiusii, Lippia sidóides and Syzigium aromaticum against larvae of Aedes aegypti and Culex quinquefasciatus." The interest for a biological assay against larvae of Aedes aegypti and Culex quinquefasciatus is due to the fact that these species are distributed by the whole national territory, being therefore an activity carried out by countless researchers of Brazil. The essential oils of Syzigium aromaticum, Hyptis martiusii and Lippia sidoides were tested in the combat of the transmitter of the dengue and of the fi lariosis, using larvae of third stadium were exposed in triplicate to different concentrations (1000, 500, 250, 100, 50, 25 and 10 ppm). The larvicidal activity was observed after ten minutes of the beginning of the treatment, in the end showed very signifi cant results, with mortality potentials of up to 100% of the tested larvae, indicating accentuated toxical effects in some representatives of the volatile compounds present in the oils. For the oils of S. aromaticum, L. sidoides and H. martiusii DL 50 of 1,0; 1,0 and 8,0 ppm, respectively, were observed. Keywords:Aedes aegypti, Culex quinquefasciatus, Hyptis martiusii, Lippia sidoides, Syzigium aromaticum, essential oil, larvicidal activity. INTRODUÇÃOO dengue é uma doença infecciosa aguda de curta duração podendo assumir formas graves e letais que vem preocupando as autoridades médico sanitárias de todo o mundo. É transmitida pelos culicídeos do gênero Aedes, especifi camente pela picada do mosquito fêmea infectado. Aedes aegypti é o principal vetor de dengue no mundo, sendo que essa espécie está amplamente distribuída nas regiões tropicais e subtropicais. No Brasil sua existência é conhecida desde o século XVII (Halsted et al., 1997).Nos últimos anos o número de casos registrados e de mortes vítimas da dengue aumentou, visto que o mosquito se tornou resistente aos inseticidas convencionais (Hemingway et al., 2000). Sabe-se que a maneira mais efi caz e ideal para o controle do dengue
Despite all the efforts to contain the HIV/AIDS epidemics, there still are individuals of unknown diagnosis. These present high risk of mortality and after diagnosis respond very poorly to treatment. Late testing also represents a reduced opportunity in controlling the transmission of HIV and causes an indirect increase in the transmission rates of other diseases, such as tuberculosis. In European countries, as well as in the United States, a great number of people, represented especially by illegal immigrants, black individuals, and women, markedly present at a later state of infection. In 1996, Brazil was the very first developing country to offer free and universal access to antiretroviral therapy, as well as easy access to HIV testing and care. Nonetheless, there is still a significant number of young and adult subjects who look for HIV/AIDS services and hospitals at later stage of infection by HIV (late presenters). Here we discuss important aspects related to the late diagnosis of HIV in Brazil and worldwide.
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