His scientific career has addressed to the study of the role of polyphenols from plant-derived foods in
their quality, and health-promoting properties in humans. On a first period regarding polyphenol
analysis as botanical and geographical origin biomarkers both in honey and in processed plant-origin
foods, to continue later with their role in organoleptic properties, to end with their role in human
health. During the last decade of the last century we discovered that UV irradiation could be used to
enhance postharvest the content of resveratrol in grapes, and this process as optimized, patented and
licensed to the company Actafarma, and the patent gave CSIC more than 1Million € in royalties until
2018. Since 2000, the group that I was leading started studies on the effects of dietary polyphenols in
human health, with an especial interest in their antioxidant activity. In 2000 we (Gil M.I. &
Tomas-Barberan, F.A.) demonstrated the high antioxidant activity of pomegranates, and particularly the
processed juices that contained high amounts of ellagitannins (Gil et al., 2000, J. Agric. Food Chem.),
and that the antioxidant activity evaluated in vitro was superior to those of red wine and green tea.
This research article has been cited over 2000 times. We also studied how processing affects the
polyphenol content and how this treatment enhanced the in vitro antioxidant activity which was related
to the high content in ellagitannins. In further studies we evaluated the bioavailability, metabolism,
and tissue distribution of these polyphenols in animal models (rat, mouse and pig) and humans,
demonstrating the relevance of the gut microbiota metabolites, as they are much more bioavailable than
the original phenolics, they persist long time in the body, and show significant biological effects,
despite decreasing the antioxidant activity evaluated in vitro. In this sense, the focus of our research
has been the identification of the polyphenol metabolites that are finally absorbed, with a particular
interest in those produced by the gut microbiota, the identification of polyphenol intake biomarkers,
and the determination of the mechanisms for the biological activity of these metabolites, using models
that are compatible with the conditions observed in vivo (metabolite concentration in the tissues, kind
of metabolite, and type of human tissue). We have also completed human intervention trials with the
objective of the evaluation of the effects of the dietary polyphenols in cardiovascular function,
intestinal and systemic inflammation, metabolic syndrome, and colorectal cancer.
