Oxidative stress is now suggested to be one of the major causes for the induction of many chronic diseases. In this context, populations consuming diets rich in fruits and vegetables have shown to have lower incidences of many oxidation-linked chronic diseases such as cancer, cardiovascular diseases and diabetes. This has led to a recent surge in interest in the use of diet as a potential tool to manage oxidation-linked diseases. Phenolic phytochemicals with antioxidant properties are now believed to be an important component in fruits and vegetables responsible for these beneficial health effects. However, ability of phytochemicals in managing diseases linked to oxidative stress is not clearly understood. Phenolic phytochemicals that have positive health benefits are believed to be functioning by countering the effects of reactive oxygen species (ROS) species generated during cellular metabolism. The known models explaining the mechanism of action do not explain the more comprehensive antioxidant-related functions in maintaining specific cellular homeostasis which contribute to its preventive mode of action. The currently accepted models are also deficient in explaining beneficial effects of phenolic phytochemicals across diverse biological systems and cell types. Here I will discuss several theories that have been suggested for the mode of action of phenolic phytochemicals by their ability to counter the negative effects of oxidative stress at late stages of pathogenecity. These are either by directly aiding the regeneration of cellular antioxidants such as glutathione or activating/inducing cellular antioxidant enzyme systems. I will also discuss a comprehensive model proposed by us for the antioxidant response-linked mechanism of action of phenolic phytochemicals at the early stages of host cellular response through modulation of enzyme response to maintain cellular homeostasis in eukaryotes and inhibiting the survival in prokaryotes.
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Back to The 56th Southeast Regional Meeting 2004 (November 10-13, 2004)