Made available in DSpace on 2014-12-17T14:10:25Z (GMT). No. of bitstreams: 1 GracielleRD_DISSERT.pdf: 641978 bytes, checksum: 570ea10863ca885dc9cff38e172d53f2 (MD5) Previous issue date: 2012-03-07 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Malaria is a major parasitic disease worldwide, accounting for about 500 million cases and causing 2 million to 3 million deaths annually. Four species are responsible for transmitting this disease to humans: Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae and Plasmodium ovale. The parasite resistance to antimalarial drugs and the usual limitations of the vector control implications are contributing to the spread of the disease. The most of significant advances in the search for new antimalarial drugs is based on natural components, the main ones being currently used antimalarial drugs derived from plants. Research on natural products of marine origin (particularly algae) show that some species possess antiplasmodial activity. Knowing that the coast of Rio Grande do Norte is home to several species of algae, the present study was to evaluate, for the first time, the antimalarial activity of ethanolic extracts of seaweed Spatoglossum schroederi, Gracilaria birdiae and Udotea flabellum against Plasmodium falciparum 3D7 strain tests and in vitro using the murine model (Plasmodium berghei) for evaluation in vivo. These species were ground, macerated with ethanol for 24 hours and the extracts concentrated in rotaevaporador (45 ? C ? 5 ? C). For in vitro tests, the extracts were diluted and tested at concentrations between 100 and 1.56 μg/ml (seven concentrations in triplicate), in order to obtain IC50 of each extract. The cytotoxicity tests with macrophages and BGM were performed using the MTT colorimetric assay. BGM macrophages and cells were distributed in 96 wells per plate (1x 105 to macrophages and 1x104 cells per well for BGM) and incubated for 24h at 37 ? C. The ethanol extracts were diluted and tested at concentrations of 100 to 1,56 μg/ml (seven concentrations in triplicate). After periods of 24 hours of incubation with the extracts, 100 μg of MTT was added to each well, and 3 hours elapsed, the supernatant was removed and added 200 μl of DMSO in each well. The absorbance of each well was obtained by reading on a spectrophotometer at 570 nm filter. To evaluate the acute toxicity in vivo, Swiss mice received a single dose (oral) 2000 mg/kg/animal of each extract tested. The parameters of acute toxicity were observed for 8 days. For in vivo tests, Swiss mice were inoculated with 1x105 erythrocytes infected with P. berghei. The treatment was given first to fourth day after infection with 0.2 ml of the extracts in doses of 1000 and 500 mg//g animal. The negative control group received 0.2 ml of 2% Tween-20, whereas the positive control group received sub-dose of chloroquine (5 mg/kg/animal). The assessment of antimalarial activity was done by suppressing suppressing the parasitemia at 5 and 7 days after infection. The growth inhibition of parasites was determined relative to negative control (% inhibition = parasitaemia in control - parasitemia in sample / parasitemia control x 100), the mortality of animals was monitored daily for 30 days The results showed that algae Spatoglossum schroederi and Udotea flabellum showed antimalarial activity in vitro, with reduced parasitemia of 70.54% and 54, respectively. The extracts of the three algae tested showed moderate to high cytotoxicity. Algae S. schroederi and U. flabellum were active against P. berghei only at doses of 500 mg / kg with reduction ranging from 54.58 to 52.65% for the fifth day and from 32.24 to 47.34% for the seventh day, respectively. No toxicity was observed in vivo at the dose tested, over the 8 days of observation. Although preliminary data, the bioactive components in those possible seaweed may be promising for the development of new anti-malarial drugs / A mal?ria ? a maior doen?a paras?tica mundial, respons?vel por cerca de 500 milh?es de casos e causando 2 a 3 milh?es de mortes anualmente. Quatro esp?cies s?o respons?veis pela transmiss?o dessa doen?a ao homem: Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae e Plasmodium ovale. A resist?ncia do parasito aos antimal?ricos usuais e as limita??es existentes no combate ao vetor s?o implica??es que contribuem para a expans?o dessa parasitose. Os avan?os mais significativos na busca de novos medicamentos contra a mal?ria baseiam-se em componentes naturais, sendo os principais antimal?ricos atualmente utilizados derivados de plantas. Pesquisas com produtos naturais de origem marinha (particularmente as algas) mostram que algumas esp?cies possuem atividade antiplasm?dica. Sabendo que o litoral do Rio Grande do Norte abriga v?rias esp?cies de algas, o presente estudo consistiu em avaliar, pela primeira vez, a atividade antimal?rica dos extratos etan?licos das algas Spatoglossum schroederi, Gracilaria birdiae e Udotea flabellum contra a cepa 3D7 Plasmodium falciparum em testes in vitro e utilizando o modelo murino (P. berghei) para avalia??o in vivo. As algas foram trituradas, maceradas com etanol por 24 horas e os extratos concentrados em rotaevaporador (45? C ? 5?C). Para os testes in vitro, os extratos foram dilu?dos e testados nas concentra??es entre 100 e 1,56 μg/ml (sete concentra??es em triplicata), com a finalidade de obten??o da CI50 de cada extrato. Os testes de citotoxicidade com macr?fagos e c?lulas BGM foram realizados usando o ensaio colorim?trico MTT. Macr?fagos e c?lulas BGM foram distribu?das em 96 po?os por placa (1x 105 para macr?fagos e 1x104 c?lulas por po?o para BGM), sendo incubadas por 24h a 37?C. Os extratos etan?licos foram dilu?dos e testados nas concentra??es de 100 at? 1,56 μg/ml (sete concentra??es em triplicata). Ap?s per?odos de 24h de incuba??o com os extratos, 100 μl de MTT foi adicionado a cada po?o, e decorridas 3h, o sobrenadante foi removido e adicionou-se 200 μl DMSO em cada po?o. A absorb?ncia de cada po?o foi obtida atrav?s de leitura em espectrofot?metro com filtro de 570 nm. Para avaliar a toxicidade aguda in vivo, camundongos Swiss receberam dose ?nica (oral) de 2000 mg/kg/animal dos extratos testados. Os par?metros de toxicidade aguda foram observados durante 8 dias. Para os testes in vivo, camundongos Swiss foram inoculados com 1x105 hem?cias infectadas com Plasmodium berghei. O tratamento deu-se do primeiro ao quarto dia ap?s a infec??o, com 0,2 ml dos extratos em doses de 1000 e 500 mg/kg/animal. O grupo controle negativo recebeu 0,2 ml de Tween-20 2%, enquanto que o grupo controle positivo recebeu sub-dose de cloroquina (5 mg/kg/animal). A avalia??o da atividade antimal?rica foi feita atrav?s da supress?o da parasitemia no 5? e 7? dias ap?s infec??o. A inibi??o do crescimento dos parasitos foi determinada em rela??o ao grupo controle negativo (% inibi??o = parasitemia do controle parasitemia com amostra/ parasitemia do controle x 100); a mortalidade dos animais foi acompanhada diariamente por 30 dias. Os resultados mostraram que as algas Spatoglossum schroederi e Udotea flabellum apresentaram atividade antimal?rica in vitro, com redu??o da parasitemia de 70,54 e 54%, respectivamente. Os extratos das tr?s algas testadas mostraram citotoxicidade moderada a elevada. As algas S. schroederi e U. flabellum foram ativas contra o P. berghei apenas nas doses de 500 mg/kg com redu??o variando de 54,58 a 52,65% para o quinto dia e 32,24 a 47,34% para o s?timo dia, respectivamente. N?o foi observada toxicidade in vivo para a dose testada, durante os 8 dias de observa??o. Embora sejam dados preliminares, os poss?veis componentes bioativos presentes nessas algas marinhas podem ser promissores para o desenvolvimento de novas drogas antimal?ricas