Natural Phenolic Antioxidants in Human Fluids: Analytical Approaches and Antioxidant Capacity Studies

Abstract

Phenolic compounds are the most abundant natural antioxidants in our diet. Epidemiological studies have shown the possible prevention effects of consumption of fruits and vegetables rich in phenolic compounds on degenerative diseases, such as cardiovascular diseases and cancers. However, there is a serious lack of fundamental knowledge on the uptake and metabolism of phenolic compounds in humans. It is clear that phenolic molecules, only absorbed by humans, can exert biological effects. This review presents a current knowledge on the analytical methods, antioxidant capacity measurements, as well as research strategies related to natural phenolic antioxidants on human health. Both GC-MS and LC-MS have proved to be very useful analytical techniques that can be employed to identify and quantitate targeted phenolic antioxidants and their metabolites in biofluids. Free radical quenching tests provide a direct measurement of antioxidant capacity but lack specificity and may oversimplify the in vivo human physiological environment. Research strategies are diverse and mainly focused on positive health effect of antioxidants. In the future studies, multiple potential bioactivities, both positive and negative, should be considered.