Navegando por Assunto "Ensaio cometa"

Agora exibindo 1 - 3 de 3

Acesso aberto (Open Access)
Application of the comet assay in erythrocytes of Oreochromis niloticus (Pisces): a methodological comparison
(2009) CHRISTOFOLETTI, Cintya Aparecida; DAVID, José Augusto de Oliveira; FONTANETTI, Carmem Silvia
The present study applied the comet assay to erythrocytes of Oreochromis niloticus with the aim of improving protocols to detect DNA damage in these cells, by using two distinct pHs (pH = 12.1 and pH > 13) and evaluating whether there is a correspondence between silver and ethidium bromide staining. Comets were visually examined and, the frequency of cells with and without damage was obtained, as well as the distribution of classes and scores. By using the Kruskal-Wallis test, our results revealed that pH 12.1 is more effective, although both pHs can be used. Our findings also suggest that silver staining can substitute ethidium bromide, an expensive and highly toxic stain that requires specific equipment for examination.
Acesso aberto (Open Access)
Avaliação in vitro dos possíveis efeitos citotóxicos e genotóxicos do alcalóide julocrotina em linfócitos humanos
(Universidade Federal do Pará, 2011-11-04) CORREA, Regianne Maciel dos Santos; BAHIA, Marcelo de Oliveira; http://lattes.cnpq.br/3219037174956649
Leishmaniasis is considered a public health problem, mainly due to the presence of different species of enzootic Leishmania, involving many different hosts and insect vectors. The pentavalent antimony remain the first choice drugs for the treatment of leishmaniasis for more than 50 years, however, its use has been compromised due mainly to the parasite developed resistance to the drug. Thus, the choice of drugs derived from plants based on the study and use of traditional medicine practices should appear as a new strategy for the control of leishmaniasis. However, it is important to note that some of these drugs can be toxic to the body and may even have genotoxic properties, causing changes in DNA with consequent increased risk of carcinogenesis. Julocrotine (2 -[N-(2-methylbutanolyl)]-N-phenylethylglutarimide) is an alkaloid isolated from the species Croton pullei var. glabrior Lanj. (Euphorbiaceae), widely found in the Amazon jungle and known to possess potent leishmanicidal effect. Thus, the present study evaluated the cytotoxic and genotoxic effects of julocrotina using the MTT and the Comet Assays in cultured human lymphocytes. Our results showed that the alkaloid did not show cytotoxicity in human lymphocytes at the concentrations tested. However, julocrotine showed to be genotoxic to human lymphocytes treated with the highest concentration (632μM) of the substance. Although the cytotoxicity results seem promising with respect to the use of julocrotina in the treatment of leishmaniasis, the genotoxic effect observed reinforces the need to obtain the necessary cautions for its use as an herbal leishmanicidal.
Acesso aberto (Open Access)
Estudos de citotoxicidade e genotoxicidade de Eleutherine plicata Herb
(Universidade Federal do Pará, 2014-09-30) GALUCIO, Natasha Costa da Rocha; BAHIA, Marcelo de Oliveira; http://lattes.cnpq.br/3219037174956649; DOLABELA, Maria Fâni; http://lattes.cnpq.br/0458080121943649
The purpose of this study was phytochemical studies of E. plicata, and to evaluate the cytotoxicity, the role of oxidative stress and genotoxicity. The powder of E. plicata bulbs underwent maceration with ethanol, the solution concentrated to residue in rotaevaporator. The ethanol extract was subjected to fractionation by open column chromatography over silica gel, being used as the mobile phase solvents of increasing polarity. The dichloromethane fraction was subjected to fractionation by preparative layer chromatography using dichloromethane as mobile phase, and 3 subfractions obtained. The ethanol extract, fractions and subfractions were subjected to chromatographic and spectrophotometric analysis. All samples were subjected to the tests: cellular viability (MTT), the antioxidant capacity (DPPH), comet and micronucleus assays. From the ethanol extract obtained a rich fraction naphthoquinone (dichloromethane fraction). Fractionation of this led to the isolation of: S1, S2 (major fraction), and fraction of minority S3 (unidentified, not tested). Chromatographic studies and spectrophotometric allowed the identification of S2 (isoeleuterin). Fractionation contributed positively to cytotoxicity on VERO cells, the sample being more cytotoxic to S1. The cytotoxicity in HepG2 cells was concentration dependent, being the fractionation did not contribute positively to this. Also, over time, the longer the exposure time, the lower the cytotoxicity to HepG2 cells. The maximum antioxidant activity was observed for subfraction S1, and this low genotoxicity possessed by both methods and it was the most cytotoxic. The dichloromethane fraction has an intermediate antioxidant capacity, but had a high genotoxicity in micronucleus assay. The isoeleuterin (S2) was lower antioxidant capacity, lower cytotoxicity and genotoxicity conflicting results. The ethanol extract possessed the lowest antioxidant capacity, moderate genotoxicity and lower cytotoxicity. When analyzing the results occur that: a subfraction S1 is the most promising candidate as the antimalarial drug, as have cytotoxicity and genotoxicity rates at acceptable levels. The isoeleuterin needs additional research on 11 genotoxicity. Regarding the dichloromethane fraction was not advisable to use for the development of an antimalarial drug, since it is more genotoxic.