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Previous issue date: 2014-10-20 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / A prospec??o de polissacar?deos farmacologicamente ativos provenientes de subprodutos agr?colas ainda ? uma pr?tica pouco explorada no meio cient?fico. Dessa forma, este trabalho pretendeu ampliar o conhecimento relacionado ?s atividades farmacol?gicas de polissacar?deos extra?dos do sabugo de milho. A partir da farinha de sabugo de milho, um extrato polissacar?dico foi obtido ao combinar ondas de ultrassom em meio alcalino, e ao final do processo o produto foi denominado de EPSM. Esse extrato foi caracterizado fisico-quimicamente e, atrav?s de ensaios in vitro, foi avaliado como agente antioxidante, citot?xico, anticoagulante e imunomodulator. Os resultados indicaram que o EPSM apresentou significativa a??o quelante de metal, al?m de n?o apresentar efeito t?xico para c?lulas de linhagem normal, mas evidenciar efeito citot?xico contra as c?lulas tumorais HeLa, quando causou a morte celular por apoptose. Em adi??o, outros efeitos farmacol?gicos foram observados, o EPSM diminuiu a produ??o de ?xido n?trico (NO) por macr?fagos ativados, e estendeu o tempo de coagula??o sangu?nea quando avaliado pelo ensaio de APTT. Posteriormente, fra??es metan?licas, etan?licas e cet?nicas foram obtidas a partir do fracionamento dos polissacar?deos presentes no EPSM. Foram obtidas cinco fra??es metan?licas, seis fra??es etan?licas e duas cet?nicas; e todas avaliadas quanto ?s atividades antioxidante, citot?xica, anticoagulante e imunomodulat?ria. Dentre as fra??es, E1.4 exibiu significativo efeito qualante de metal, a??o t?xica em c?lulas HeLa por indu??o da apoptose, reduziu a produ??o de NO por macr?fagos ativados, e ampliou o tempo de coagula??o sangu?nea. Esses resultados sinalizaram que os polissacar?deos farmacologicamente ativos do EPSM estariam presentes na fra??o E1.4. A partir do fracionamento da E1.4 foram obtidas seis subfra??es polissacar?dicas com tamanhos distintos: -3; 3-10; 10-30; 30-50; 50-100 e +100 KDa. Cerca de 80% dos polissacar?deos de E1.4 apresentou tamanho inferior a 10 KDa, e todas as subfra??es apresentaram mais de 61% de a??car em suas composi??es qu?micas. Essas subfra??es exibiram diferentes composi??es monossacar?dicas, mas todas apresentaram xilose. As subfra??es evidenciaram distintos efeitos nos ensaios farmacol?gicos in vitro. As subfra??es de menor tamanho (< 30 KDa) demonstraram maior atividade quelante de metal e maior atividade citot?xica contra c?lulas tumorais. As intermedi?rias (entre 30 e 100 KDa) diminu?ram mais a produ??o de NO por macr?fagos ativados, mas a de maior tamanho (+100 KDa) modulou um maior n?mero de citocinas inflamat?rias, e demonstrou um maior efeito anticoagulante. Portanto, a an?lise conjunta dos resultados indica que os polissacar?deos farmacologicamente ativos do ESPM s?o heteroxilanas e foram concentrados nas subfra??es de E1.4, al?m disso, os efeitos farmacol?gicos dessas heteroxilanas dependem do seu tamanho molecular. / Prospecting pharmacological active polysaccharides from agricultural
byproducts, such as corncobs, is an underexplored practice in the scientific community.
Thus, this work aims to expand knowledge about pharmacological activities of
polysaccharides extracted from corncobs. From corn cob flour a extract was obtained by
ultrasound waves in an alkaline medium, and the end of the process the product was
termed PECC (polysaccharidic extract from corncobs). This extract was physicochemical
characterized and evaluated by in vitro assays as an antioxidant, cytotoxic,
anticoagulant and imunomodulator agent. Results indicated significant activity metal
chelating by PECC, and the use of PECC in cell culture cells showed no toxic effects to
normal cell lines, but toxic action against HeLa tumor cells due promoting cell death by
apoptosis. In addition, other pharmacological effects were observed, the PECC
decreased nitric oxide (NO) production by activated macrophages, and prolonged blood
clotting time through APTT assay. Then methanolic, ethanolic and ketone fractions
were obtained from fractionation of PECC polysaccharides. Five methanolic fractions,
six ethanolic fractions and two ketones were obtained; and all fractions were evaluated
for antioxidant, cytotoxic, anticoagulant, immunomodulatory activities. E1.4 fraction
exhibited significant metal chelating effect, a toxic action to induce apoptosis in HeLa
cells, decreased NO production by activated macrophages, and extended blood clotting
time. These results showed that the PECC pharmacological active polysaccharides
would be present in the fraction E1.4. From fractionation of E1.4 polysaccharide six
subfractions with different sizes were obtained: <3; 3-10; 10-30; 30-50; 50-100 and
>100 KDa. About 80% of E1.4 polysaccharides had lower size to 10 KDa, and all the
subfractions showed over 61% sugar in their chemical compositions. These subfractions
exhibited different monosaccharide compositions, but xylose was presented in all of
them. The subfractions exhibited distinct pharmacological effects in in vitro assays.
Smaller subfractions (<30 KDa) had highest metal chelating activity and greater toxic
action in tumor cells. The intermediate fractions (between 30-100 KDa) decreased more
NO production of activated macrophages, for other side, the larger size (>100 KDa)
modulated a greater number of inflammatory cytokines, and the had greatest
anticoagulant effect. Therefore, when analyzing all the results together it is evident that
the PECC pharmacological polysaccharides are heteroxylans, and were concentrated in
E1.4 fraction, and heteroxilanas pharmacological effects depends on their molecular
size. Thus, corncobs could be used as source from molecules with biotechnology
potential
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/19441 |
| Date | 20 October 2014 |
| Creators | Silveira, Raniere Fagundes de Melo |
| Contributors | 76111830449, http://lattes.cnpq.br/4651814546820796, Barbosa, Carlos Augusto Galv?o, 67269621420, http://lattes.cnpq.br/5004397230198722, Lanza, Daniel Carlos Ferreira, 05372896663, http://lattes.cnpq.br/6851351991421755, Albuquerque, Ivan Rui Lopes de, 91237386420, http://lattes.cnpq.br/2266021166245706, Bezerra, Ranilson de Souza, 74436767434, http://lattes.cnpq.br/2205151409139871, Rocha, Hugo Alexandre de Oliveira |
| Publisher | Universidade Federal do Rio Grande do Norte, PROGRAMA DE P?S-GRADUA??O EM BIOQU?MICA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| 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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