Loading...
6 results
Search Results
Now showing 1 - 6 of 6
- The effect of high concentrations of vitamin C on a H2O2 - oxidative stress induced yeast modelPublication . Costa, Ana Rita; Cunha, Sofia; Nascimento, Ana Paula; Vieira, Mónica; Prudêncio, CristinaNowadays, the ageing of population is conducting to a rise in the number of individuals with age-related illnesses, in which neurodegenerative diseases (ND) are included. Regardless of many variations in etiology and diverse mechanisms of cell injury, most of ND share high levels of oxidative stress, which have been highly referred not only as an underlying factor, but also as a feature. Thus, an actual challenge is to evaluate the role of antioxidants on oxidative stress states and evaluate the magnitude of possible therapeutic effects of these agents. In the present study, the toxic effect of hydrogen peroxide (H2O2) and the antioxidative function of vitamin C were investigated using Saccharomyces cerevisiae as a model. Results were achieved by exposing the yeast model to different concentrations of H2O2 and vitamin C, itself or combined, and colony forming units counting after 48 h incubation at 30ºC in Yeast Extract Peptone Dextrose agar plates. The results demonstrated that H2O2 exposure decreased yeast cells viability in a dose-dependent manner and that, at an optimal concentration, vitamin C was able to revert its effects. These results improved the understanding of the reversal effect of antioxidant treatment and, therefore, may be helpful on providing insights on a natural antioxidant-based therapy for ND.
- Development of a chromatographic method for simultaneous analysis of glutathione formsPublication . Teixeira, Dulce; Coelho, Pedro; Prudêncio, Cristina; Azenha, Manuel; Vieira, MónicaReduced glutathione (GSH)is the most abundant low molecular weight thiol-containing tripeptide (glycine, cysteine, and glutamate) which is synthesized in the cells. GSHplays critical roles in protecting cells from oxidative damage and the toxicity of xenobiotics. Besides, it is also involved in the regulation of intracellular redox homeostasis, which leads to its oxidation into oxidized glutathione (GSSG). Determining the ratio of GSH/GSSG in different biological samples is a major procedure for the evaluation of an individual’s oxidative status and can be a potential biomarker of oxidative stress.
- Modulation of oxidative stress with Vitamin E in Sacharomyces cerevisiaePublication . Alves, M.; Cunha, Sofia; Costa, A.; Nascimento, Ana Paula; Vieira da Silva, Manuela; Prudêncio, CristinaNeurodegenerative diseases, such as Parkinson’s Disease or Alzheimer’s Disease, are characterized by the death of a subset of neurons over long periods of time.
- Melanoma and obesity: Should antioxidant vitamins be addressed?Publication . Oliveira, Sofia; Coelho, Pedro; Prudêncio, Cristina; Vieira, Mónica; Soares, Raquel; Guerreiro, Susana G.; Fernandes, RúbenMelanoma is an aggressive form of skin cancer refractory to conventional therapies. Obesity has reached epidemic dimensions acting as a risk factor for several cancer types, such as melanoma. Several reactive species of oxygen are also involved in melanoma initiation and progression. Low levels of antioxidant content and/or activity in lightly pigmented cells could expose them to an extremely oxidative environment and rise the susceptibility to oxidative damage and consequently loss of cell homeostasis. Despite the knowledge about melanoma biology, pathogenesis and developed therapies, is extremely important to understand the antioxidant modulation of melanoma under an environment of obesity, especially the effect of some natural compounds of the diet, such as antioxidant vitamins A, C and E and selenium in order to establish alternatives to conventional therapies, which are known to be ineffective against melanoma.
- Oxidative Stress Modulation and Radiosensitizing Effect of Quinoxaline-1,4-Dioxides DerivativesPublication . Silva, Liliana; Coelho, Pedro; Teixeira, Dulce; Monteiro, Armanda; Pinto, Gabriela; Soares, Raquel; Prudêncio, Cristina; Vieira, MónicaQuinoxaline-1,4-dioxide (QNX) derivatives are synthetic heterocyclic compounds with multiple biological and pharmacological effects. In this study, we investigated the oxidative status of quinoxaline-1,4-dioxides derivatives in modulating melanoma and glioma cell lines, based on previous results from the research group and their capability to promote cell damage by the production of Reactive Oxygen Species (ROS).
- Study of oxidant and anti-oxidant molecular alterations in an eukaryotic modelPublication . Allen, A.; Cunha, S.; Prudêncio, Cristina; Vieira, MónicaMitochondrial dysfunction and protein aggregation are two phenomena that have been correlated with neurodegenerative diseases and are both interlinked with cellular oxidative stress. Mitochondrial dysfunction is associated with nucleic acid damage and protein aggregation with mistakes in protein folding. However, aggregation has not yet been defined as a cause or consequence of neurodegenerative diseases.