Dietary antioxidants have been a dynamic research topic in the agricultural sciences for a number of years, and, as the evidence suggests, antioxidants may be beneficial in reducing oxidative stress, which is believed to be the culprit of chronic illnesses such as cardiovascular disease, cancer, and chronic inflammation, among others.

“We hope our work can add to the understanding of antioxidants from a chemistry point of view and facilitate the research of developing effective dietary antioxidants for disease prevention and health promotion.”

Logically, it is important to know the dietary antioxidant capacity of foods and dietary supplements. However, there are many different antioxidant activity quantitation methods that lead to confusion among researchers and the food industry.

Our review article analyzed the chemical principles behind these assays and exposed the advantages and limitations of the assays by putting them into the perspective of a broader scope of antioxidants. Evidently, there is a great need of such a review, as I received numerous requests for reprints.

The high citation rate is an indication that the field of antioxidants is a very active research area and that researchers want to become more knowledgeable about the antioxidant capacity assays.

The article is a critical review of the chemical principles of common in vitro antioxidant assays. It also summarized our own work regarding different methods of measuring the radical scavenging capacity of food and biological samples.

Antioxidant is a household word and you may think you know the meaning well enough. If you do, think again. You will find it is actually much more complex. Our article sheds some light on only one aspect of antioxidants—the antioxidant capacity as measured in a test tube by different methods.

It may help you to critically interpret the antioxidant power labeled on the bottle of a beverage you may buy from your neighborhood grocery store. In terms of the benefits of antioxidants to human health, it is a totally different and far more complex story, not even touched upon in our article.

When I was employed at Brunswick Laboratories (Norton, MA. USA) from 2001 to 2004, one of my roles was to develop assays to measure antioxidant capacity using chemical reactions. My colleague, Dr. Boxin Ou (one of the coauthors of the paper) and I, faced the challenge of developing new assays and choosing the scientifically sound ones from among numerous reported protocols in order to fully measure the antioxidant capacity of food and biological samples received from our clients.

To make the most sensible choices, we analyzed the pros and cons of existing methods. In the process, we realized that it is a non-trial task to comprehensively and correctly evaluate antioxidant capacity. It is not possible to have a "one-size-fits-all" approach in antioxidant measurements. Instead, multiple assays are needed and each assay should build on solid chemistry principles in measuring one aspect of antioxidants.

Lack of funding was the major hurdle. We worked hard and were successful in securing a highly competitive grant from the USDA through the Small Business Innovative Research (SBIR) Fund.

An aging population and age-related diseases are on the rise as the baby boomers in the USA are at or near the retirement age. Globally, aging populations are a great concern in many countries, such as in China. Consequently, health-care costs become a greater social burden.

The quality of life can be improved if we can effectively alleviate the symptoms of, or prevent, age-related diseases. Mounting evidence suggests that dietary antioxidants play a pivotal role in disease prevention.

We hope our work can add to the understanding of antioxidants from a chemistry point of view and facilitate the research of developing effective dietary antioxidants for disease prevention and health promotion. We also hope that our work can provide a scientific basis for the governmental regulatory bodies and the food and nutraceutical industries to set standardized protocols for antioxidant capacity measurements.