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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
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/13079 |
| Date | 07 March 2012 |
| Creators | Dantas, Gracielle Rodrigues |
| Contributors | CPF:59626305487, http://lattes.cnpq.br/4863082845974813, Pontes, Daniel de Lima, CPF:61954225334, http://lattes.cnpq.br/1903229358912987, Rocha, Hugo Alexandre de Oliveira, Andrade Neto, Valter Ferreira de |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Ci?ncias Biol?gicas, UFRN, BR, Biodiversidade; Biologia Estrutural e Funcional. |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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