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Previous issue date: 2009-03-26 / Recently, it has been a increasing interest in the antioxidative role of natural products to aid
the endogenous protective biological systems against the deleterious effects of oxygen (ROS)
and nitrogen (RNS) reactive species. Many antioxidant compounds, naturally occurring from
plant sources. Natural antioxidants can protect and prevent the human body from oxidative
stress and retard the progress of many diseases in which free radical are involved. Several
plants used in the folk medicine to treat certain disorders that are accompanied by
inflammation and other pharmacological properties have been proved their attributed
properties, such antioxidant activity. Turnera ulmifolia Linn. var. elegans (Turneraceae),
frequently employed by population as a medicinal plant, demonstrated antioxidant activity by
in vitro and in vivo assays, using its leaf hydroethanolic extract (10%) he in vitro DPPH
radical-scanvenging activity showed a strong antioxidant activity (86.57% ? 0.14), similar to
Carduus marianus and catequine effects. For the in vivo assays, adult female Wistar rats
(n=48) with carbon tetrachloride hepatic injury induced (2,5mL/kg i.p.) were used, Six groups
or rats were uses (n=8) [G1 = control (1,25 mL/kg i.p. vehicle); G2 = CCl4 (2,5 mL/kg i.p.);
G3 = CCl4 + extract 7 days (500 mg/kg p.o.); G4 = CCl4 + Legalon? 7 days (50 mg/kg p.o.),
G5 = CCl4 + extract 21 days (500 mg/kg p.o.) e G6 = CCl4 + Legalon? 21 days (50 mg/kg
p.o.)]. The hepatic oxidative injury was evaluated through biochemical parameters [alanine
amino transferase (ALT), aspartate amino transferase (AST)] histopathological study, while
thiobarbituric acid reactive products (TBAR), glutathione (GSH), catalase (CAT), superoxide
dismutase (SOD), and glutathione peroxidase (GPx) levels were used to evaluate proantioxidant
parameters. The plant extract tested was found effective as hepatoprotective as
evidenced by a decreasing in the ALT and AST activities (p<0.001) and TBAR (plasma,
p<0.001 and liver, p<0.001). Levels of GSH (blood, p<0.001 and liver, p<0.001) and
antioxidant enzymes [CAT erythrocyte (p<0.05) and hepatic (p<0.01); SOD erythrocyte
(p<0.001) and hepatic (p<0.001); GPx erythrocyte (p<0.001) and hepatic (p<0.001)] were
also significantly increased. Histopathological changes induced by CCl4 were significantly
reduced by the extract treatment. The data obtained were comparable to that of Legalon?, a
reference hepatoprotective drug. The results showed that T. ulmifolia leaf extract protects
against CCl4 induced oxidative damage. Therefore, this effect must be associated to its
antioxidant activity, attributed to the phenolic compounds, present in these extract, which can
act as free radical scavengers / Atualmente existe um crescente interesse no estudo dos antioxidantes, classe de subst?ncias
que protegem os sistemas biol?gicos dos efeitos delet?rios das esp?cies reativas de oxig?nio
(ERO) e de nitrog?nio (ERN). Muitos desses antioxidantes s?o mol?culas de origem vegetal
que contribuem para a preven??o e para o tratamento de doen?as nas quais o estresse
oxidativo est? envolvido. Na medicina popular, plantas com comprovada atividade antiinflamat?ria,
apresentam diversas atividades farmacol?gicas, dentre elas, a antioxidante.
Turnera ulmifolia Linn. var. elegans (Turneraceae), uma planta medicinal, largamente
utilizada pela popula??o, apresentou atividade antioxidante quando avaliada in vitro e in vivo,
utilizando-se o extrato hidroetan?lico (10 %) obtidos das folhas dessa planta. A capacidade
antioxidante in vitro desse extrato foi avaliada atrav?s do seq?estro do radical 1,1-difenil-2-
picril-hydrazyl (DPPH ). O resultado apresentou um marcado potencial antioxidante ao
seq?estrar 86,57%?0,14 do radical DPPH , compar?vel ao obtido com as subst?ncias de
refer?ncia. No ensaio in vivo, empregando-se modelo experimental murino (48 ratas Wistar),
inj?ria hep?tica foi induzida com CCl4 (2,5 mL/kg i.p. dose ?nica) e o dano oxidativo
hep?tico foi avaliado atrav?s da atividade das transaminases (ALT e AST) e pelo exame
histopatol?gico, enquanto que as subst?ncias reativas ao ?cido tiobarbit?rico (SRAT),
conte?do de glutationa reduzida (GSH) e atividade das enzimas catalase (CAT), super?xido
dismutase (SOD) e glutationa peroxidase (GPx) foram os par?metros pr?-antioxidante
avaliados. Os animais foram divididos em seis grupos (n=8) [G1 = controle (1,25 mL/kg i.p.
de ve?culo); G2 = CCl4 (2,5 mL/kg i.p.); G3 = CCl4 + extrato 7 dias (500 mg/kg p.o.); G4 =
CCl4 + Legalon? 7 dias (50 mg/kg p.o.), G5 = CCl4 + extrato 21 dias (500 mg/kg p.o.) e G6 =
CCl4 + Legalon? 21 dias (50 mg/kg p.o.)]. O p?s-tratamento com o extrato provocou um
decr?scimo na atividade da ALT e AST (p<0,001) e de SRAT (plasma, p<0,001 e f?gado,
p<0,001), aumentando o conte?do da GSH (sangue, p<0,001 e em f?gado, p<0,001), bem
como a atividade das enzimas antioxidantes, [CAT eritrocit?ria (p<0,05) e hep?tica (p<0,01);
SOD eritrocit?ria (p<0,001) e hep?tica (p<0,001); GPx eritrocit?ria (p<0,001) e hep?tica
(p<0,001)]. A an?lise histopatol?gica mostrou uma redu??o do dano hep?tico causado pelo
CCl4. Os resultados obtidos com o extrato foram an?logos aqueles do tratamento com
Legalon?, padr?o antioxidante, utilizado in vivo. Com base nesses dados, conclui-se que o
extrato de folhas de T. ulmifolia apresenta capacidade hepatoprotetora diante do quadro de
estresse oxidativo induzido pelo CCl4. Efeitos estes, que, provavelmente, est?o associados ?
atividade antioxidante detectada, atribu?das ?s subst?ncias fen?licas presentes no extrato, que
devem agir como seq?estradores de radicais livres, bloqueando as rea??es em cadeias
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/13468 |
| Date | 26 March 2009 |
| Creators | Brito, Naira Josele Neves de |
| Contributors | CPF:20054548420, http://lattes.cnpq.br/0321740024191482, Ferreira, Aurigena Antunes Ara?jo, CPF:83806059420, http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4792980U2, Rodriguez, Jorge Alberto Lopez, CPF:27657779420, http://lattes.cnpq.br/6940701204545519, Almeida, Maria das Gra?as |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Ci?ncias Farmac?uticas, UFRN, BR, Bioan?lises e Medicamentos |
| 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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