Oxidative Stress and Antioxidants - A Critical Review on in-vitro Antioxidant Assays

Authors: KOTHA, RAGHAVENDHAR - University Of Maryland; TAREQ, FAKIR - University Of Maryland; YILDIZ, ELIF - Uludag University; Luthria, Devanand - Dave

Submitted to: Molecules
Publication Type: Literature Review
Publication Acceptance Date: 11/19/2022
Publication Date: 12/1/2022
Citation: Kotha, R.R., Tareq, F.S., Yildiz, E., Luthria, D.L. 2022. Oxidative Stress and Antioxidants - A Critical Review on in-vitro Antioxidant Assays. Molecules. 11:2388. https://doi.org/10.3390/antiox11122388.
DOI: https://doi.org/10.3390/antiox11122388

Interpretive Summary: This review provides a comprehensive and critical aspect of the status of antioxidants. It outlines the challenges associated with antioxidant analysis methodologies. Antioxidants have been widely studied in the fields of biology, medicine, food, and nutrition sciences. There has been extensive data available on the causes, mechanisms, and consequences of oxidative stress in biological systems. However, the absolute health efficacy and the mode of action of exogenous dietary antioxidants are still debatable. This may be attributed to several factors, including a wide array of assays and reporting methodologies, lack of suitable standards, validated analytical procedures, bioavailability and bioaccessibility information, the correlation between different assay procedures, and detailed clinical trials. Hence, there is a significant amount of incoherence regarding the performance and acceptability of dietary antioxidants as it relates to human health. In this review, we have illustrated the variations in the current methodologies, their mechanisms, and their reported values of the antioxidant activity using six common food substrates (fruits, vegetables, processed foods, grains, legumes, milk, and dairy-related products) as documented in peer-reviewed literature. Also, we have highlighted the advantages and shortcomings of the different assays and analytical methods.

Technical Abstract: Antioxidants have been widely studied in the fields of biology, medicine, food, and nutrition sciences. There has been extensive work on the development of assays for foods and biological systems. However, the health efficacy and the possible action of exogenous dietary antioxidants are still questionable. This may be attributed to several factors, including a lackof basic understanding of the interaction of exogenous antioxidants in the body, lack of agreement of the many assays, and the lack of specificity of the assays which leads to an inability to relate specific dietary components to health outcomes. Hence, there is a significant doubt regarding the relationship of dietary antioxidants to human health. In this review, the variations in the current methodologies, their mechanisms, and the highly varying values for six common food substrates (fruits, vegetables, processed foods, grains, legumes, milk, and dairy-related products) are docuimented. Finally, we discuss the strengths and weaknesses of the antioxidant assays and examine the challenges in correlating antioxidant activity of foods to human health