Dietary oxidative stress and antioxidant defense with an emphasis on plant extract administration.
Study Goal
The researchers aimed to examine the effects of antioxidant supplementation, particularly polyphenolic compounds, in vivo, focusing on their potential to promote oxidative stress when administered separately from a diet, especially during exercise.
Results Summary
The study found that polyphenolic antioxidants may promote oxidative stress in animals and humans when given as supplements, particularly during exercise, contrasting with their in vitro potency. It highlights the need for careful examination of in vitro findings before applying them to in vivo models.
Population
Animals and humans, particularly in the context of exercise.
Effective Dosage
Not specified
Duration
Not specified
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
Polyphenolic compounds present in plant extracts | increase | antioxidant activity | in vitro | - | are potent antioxidants | #1 |
Polyphenolic compounds present in plant extracts | increase | oxidative stress | animals and humans | - | may promote oxidative stress | #2 |
antioxidant molecules administered separately and not as part of a diet | increase | oxidative stress | animals and humans | - | may promote oxidative stress | #3 |
antioxidant supplementation | no change | applicability of in vitro findings | - | - | demonstrates the need for a meticulous examination of the in vitro findings before applying them to in vivo models | #4 |
Eukaryotic cells generally function in a reduced state, but an amount of reactive species is essential for several biochemical processes. The antioxidant network is the defensive mechanism that occurs when the concentration of reactive species exceeds a threshold. Polyphenolic compounds present in plant extracts are potent antioxidants in vitro, but they may promote oxidative stress when administered in animals and humans, especially when given as supplements in exercise, a modality usually adopted as an oxidant stimulus. This is mainly observed when antioxidant molecules are administered separately and not as part of a diet. Exercise is usually adopted as a physiological model for examining the effects of reactive species in human or animal physiology. The use of exercise as a model demonstrates that reactive species do not always have adverse effects, but are necessary in physiological processes that are beneficial for human health. This review summarizes what is known about antioxidant supplementation and demonstrates the need for a meticulous examination of the in vitro findings before applying them to in vivo models. The term "antioxidant" seems elusive, and it is more appropriate to characterize a compound as "antioxidant" if we know in which concentration it is used, when it is used, and under which conditions.