Tesis
Avaliação da atividade e mecanismo de ação antiúlcera gástrica do extrato hidroetanólico da entrecasca do caule de Virola elongata (Benth.) Warb
Fecha
2016-12-07Registro en:
ALMEIDA, Guilherme Vieira Botelho de. Avaliação da atividade e mecanismo de ação antiúlcera gástrica do extrato hidroetanólico da entrecasca do caule de Virola elongata (Benth.) Warb. 2016. 88 f. Dissertação (Mestrado em Ciências da Saúde) - Universidade Federal de Mato Grosso, Faculdade de Medicina, Cuiabá, 2016.
Autor
Martins, Domingos Tabajara de Oliveira
http://lattes.cnpq.br/3794477872946546
Martins, Domingos Tabajara de Oliveira
109.726.923-04
http://lattes.cnpq.br/3794477872946546
Jesus, Neyres Zínia Taveira de
469.179.851-04
http://lattes.cnpq.br/2760653304094924
109.726.923-04
Hiruma, Clélia Akiko
089.645.898-90
http://lattes.cnpq.br/3814504901386844
Karuppusamy, Arunachalam
706.801.091-10
http://lattes.cnpq.br/8737379045278143
Institución
Resumen
Virola elongata (Myristicaceae) is a native tree, but not endemic to Brazil, popularly
known as “mucuíba”, “bicuíba” or “ucuúba” whose stem bark is traditionally used in
the form of macerate or infusion by riverine populations for the treatment of gastric
ulcers. The present work aimed to evaluate the toxicity, activity and possible
mechanism of action of the hydroethanolic extract of the stem bark of V. elongata
(HEVe), as well as to analyze the phytochemical composition of the extract. HEVe was
obtained by maceration of the stem bark powder in 70% hydroethanolic solution (1:10,
w/v). Phytochemical analysis was carried out by phytochemical screening, revealing the
presence of phenolic compounds, flavonoids, alkaloids and phytosterols, followed by
identification of the secondary metabolites rutin, catechin and gallic acid through high-
performance liquid chromatography (HPLC). Acute toxicity of HEVe was evaluated by
the Hippocratic assay with a single dose of 2,000 mg/kg b.w. on Swiss mice, which
presented increased relative weight of the spleen in female mice and of the stomach for
males, even though no macroscopic anomalies were present, as well as a reduction in
weight gain for HEVe treated male mice. The difference found between both genders
may be related the effect of lignans on hormonal levels. Cytotoxicity assay using
hamster ovary cells (CHO-k1) and gastric adenocarcinoma cells (AGS) indicate that
HEVe can be considered as non-cytotoxic in treatments of 24 and 72 h (IC50 > 200
μg/mL). On the micronucleus assay, used to evaluate genotoxic potential, HEVe was
shown to be non-genotoxic. Antiulcerogenic activity of HEVe was evaluated through
animal models of ulcer induced by acidified ethanol, in mice, piroxicam and by
hypothermic restraint stress in Wistar rats, as well as the antiulcer activity of HEVe via
acetic acid induced chronic ulceration model. In all tested models of activity, HEVe
XVIII
presented potent gastroprotective effects. In order to determine of the possible
mechanisms of action of HEVe, its effects over gastric acid secretion in Shay’s pyloric
ligation model, the mucogenic activity through Alcian Blue method, the participation of
nitric oxide (NO) on the gastroprotective mechanism of action, the activity of
myeloperoxidase (MPO), catalase (CAT), concentrations of interleulkin-10 (IL-10),
tumor necrosis factor-α (TNF-α) interleukin-1β (IL-1β) in mice gastric tissue
homogenate were evaluated. The mechanism of action by which HEVe exerts its effects
seem to be independent form mucogenic action, but involving reduction of total acidty
and volume of gastric content, NO activity, the modulation of the expression of TNF-α
and stimulation of tissue repair, as well as reducing MPO and CAT activity, indicating
reduction on the concentration of tissue reactive oxygen species. The results obtained in
this study validate the use of the stem bark of V. elongata by the riverine population of
Mato Grosso, however, further studies are necessary to elucidate the gastroprotective
mechanism of action and the subchronic toxic potential of HEVe.