64 research outputs found
Comparison between in vitro chemical and ex vivo biological assays to evaluate antioxidant capacity of botanical extracts
The anti-oxidative activity of plant-derived extracts is well-known and confers health-promoting effects on functional foods and food supplements. Aim of this work is to evaluate the capability of two different assays to predict the real biological antioxidant efficiency. At this purpose, extracts from five different plant-derived matrices and commercial purified phytochemicals were analyzed for their anti-oxidative properties by using well-standardized in vitro chemical method (TEAC) and an ex vivo biological assay. The biological assay, a cellular membrane system obtained from erythrocytes of healthy volunteers, is based on the capability of phytochemicals treatment to prevent membrane lipid peroxidation under oxidative stress by UV-B radiation. Plant extracts naturally rich in phenols with different structure and purified phytochemicals showed different in vitro and ex vivo antioxidant capacities. A high correlation between phenolic contents of the plant-derived extracts and their ability to prevent oxidative injuries in a biological system was found, thus underlying the relevance of this class of metabolites in preventing oxidative stress. On the other hand, a low correlation between the antioxidant capacities was shown between in vitro and ex vivo antioxidant assay. Moreover, data presented in this work show how food complex matrices are more effective in preventing oxidative damages at biological level than pure phytochemicals, even if for these latter, the antioxidant activity was generally higher than that observed for food complex matrices
The soluble proteome of tobacco Bright Yellow-2 cells undergoing H2O2-induced programmed cell death
Plant programmed cell death (PCD) is a genetically controlled process that plays an important role in development and stress responses. Reactive oxygen species (ROS) are key inducers of PCD. The addition of 50 mM H2O2 to tobacco Bright Yellow-2 (TBY-2) cell cultures induces PCD. A comparative proteomic analysis of TBY-2 cells treated with 50 mM H2O2 for 30 min and 3 h was performed. The results showed early down-regulation of several elements in the cellular redox hub and inhibition of the protein repair–degradation system. The expression patterns of proteins involved in the homeostatic response, in particular those associated with metabolism, were consistently altered. The changes in abundance of several cytoskeleton proteins confirmed the active role of the cytoskeleton in PCD signalling. Cells undergoing H2O2-induced PCD fail to cope with oxidative stress. The antioxidant defence system and the anti-PCD signalling cascades are inhibited. This promotes a genetically programmed cell suicide pathway. Fifteen differentially expressed proteins showed an expression pattern similar to that previously observed in TBY-2 cells undergoing heat shock-induced PCD. The possibility that these proteins are part of a core complex required for PCD induction is discussed
A REGULATORY ROLE OF NAD REDOX STATUS ON FLAVIN COFACTOR HOMEOSTASIS IN S. cerevisiae MITOCHONDRIA
Programmed cell death in Daucus carota cell lines showing reduced expression of the top1b gene
Redox regulation in plant programmed cell death
Programmed cell death (PCD) is a genetically controlled
process described both in eukaryotic and prokaryotic
organisms. Even if it is clear that PCD occurs in plants, in
response to various developmental and environmental
stimuli, the signalling pathways involved in the triggering of
this cell suicide remain to be characterized. In this review,
the main similarities and differences in the players involved
in plant and animal PCD are outlined. Particular attention
is paid to the role of reactive oxygen species (ROS) as key
inducers of PCD in plants. The involvement of different
kinds of ROS, different sites of ROS production, as well as
their interaction with other molecules, is crucial in activating
PCD in response to specific stimuli. Moreover, the
importance is stressed on the balance between ROS production
and scavenging, in various cell compartments, for
the activation of specific steps in the signalling pathways
triggering this cell suicide process. The review focuses on
the complexity of the interplay between ROS and antioxidant
molecules and enzymes in determining the most suitable
redox environment required for the occurrence of
different forms of PCD
Different involvement of the mitochondrial, plastidial and cytosolic ascorbate-glutathione redox enzymes in heat shock responses
Relationships between NAD redox status and FAD degradation in S. cerevisiae mitochondria.
Changes in the ascorbate metabolism during programmed cell death and moderate oxidative stress in TBY-2 cells
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