**5. Conclusions**

Urolithin A, a gastrointestinal metabolite from ellagitannins, is a promising therapeutic antioxidant agent with potential pharmaceutical or food applications for the prevention of oxidative stress-associated disorders, probably though the improvement of the cell antioxidant capacity by increasing the expression of thiol-dependent peroxidases.

**Author Contributions:** Conceptualization, V.L. and M.H.; investigation, G.C., F.L., and C.C.-F., analysis, G.C.; writing—original draft preparation, G.C.; writing—review and editing, V.L. and M.H., funding acquisition, V.L. and M.H. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work has been partially financed by Universidad San Jorge and by Spanish Government grants (RTI 2018-094203-B-I00 to A.M.R and IJCI-2017-34170 to M.H.).

**Acknowledgments:** Industrias Químicas del Ebro (IQE) and Universidad San Jorge (USJ) are acknowledged for the PhD grant for Guillermo Cásedas. M.H. holds a Juan de la Cierva-Incorporación contract from the Agencia Estatal de Investigación (Spanish Government), reference number IJCI-2017-34170. We thank Antonio Martínez-Ruiz (Unidad de Investigación, Hospital Universitario Santa Cristina, Instituto de Investigación Sanitaria Princesa (IIS-IP), E-28009 Madrid, Spain) for allowing Guillermo Cásedas to perform the Western blot analysis at his lab.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
