What is it about?
Oxidative stress in the brain microvasculature is a common characteristic in models of cerebrovascular disease. It is, therefore, naturally prudent to hypothesize how antioxidant (AO) supplementation in brain vasculature, may be beneficial for combating cerebrovascular disease. Hyper doses of AOs in supplements and food, are commonly used as an ongoing remedial, ‘over the counter,’ treatment for most seasonal ailments. For the first time, this study reports the adverse effects of excess AOs on angiogenic properties of the blood-brain barrier (BBB) which have clinical implications. A medicinal tea, known as rooibos (Aspalathus linearis), commonly used in South Africa and marketed globally, for its prominent AO profile, demonstrated its effects on brain endothelial cellular (BEC) proliferation, toxicology, mitochondrial activity and permeability. In the current study, mouse BECs were seeded at passage numbers 30 to 40, at cell densities ranging from 103-106 cells/ml and were incubated at pre-determined time intervals. Daily exposure to a selected concentration range of fermented A. linearis caused exacerbated effects with dose-related decreases in cellular proliferation, and unequivocally increased impermeability across an in vitro BBB model. No toxicity was observed for all selected concentrations of A. linearis. The data conclusively show that the use of excess AOs perturb BBB functionality and angiogenic properties, adversely implicating brain homeostasis. This suggests that excess AOs will lead to an impaired response to mechanical-induced injury and pathogenic infection of the BBB, resulting in compromised patient recovery.
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Why is it important?
It is important because of the pervasive view that antioxidants is a cure to all ailments, from the common cold to treatment of strokes. Our research show that excess doses of antioxidants may indeed be detrimental to cellular function and tissue repair, especially with regards to brain capillaries
Perspectives
Our research data was puzzling at first as we treated brain endothelial cells with the common tea (Rooibos), which has high quantities of the molecule Aspalathin, a well known antioxidant. However, understanding that all cells produce and regulate their own endogenous antioxidants which are strictly regulated, and that the addition of exogenous antioxidants might suppress the production of endogenous antioxidants, destabilizing the redox balance of the cell which is crucial for cellular function.
Prof David Fisher
University of the Western Cape
Read the Original
This page is a summary of: The blood-brain barrier is adversely affected by excess Aspalathus linearis derived anti-oxidants, South African Journal of Botany, March 2017, Elsevier,
DOI: 10.1016/j.sajb.2017.01.113.
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