**4. Conclusions**

All in all, our findings indicated that wild Italian blackthorn fruit is rich in polyphenol compounds, shows an in vitro antioxidant activity, and exhibits a selective growth inhibition of some potentially pathogenic bacteria strains. Moreover, this study is the first to evaluate an In Vivo antioxidant activity of PSF. In particular, our findings indicated that the oxidative stress arising in HFD group is decreased in liver and brain tissues by the intake of blackthorn fruit. The PSF supplementation demonstrated In Vivo antioxidant capacities, reducing liver and brain oxidative stress, probably due to the presence of polyphenols, such as rutin, 4-hydroxybenzoic acid, gallic acid, trans-sinapic acid, quercetin, trans-ferulic acid, caffeic acid, rosmarinic acid, trans coumaric acid, genistin, and myricetin, which were identified in the blackthorn fruit.

Thus, it is supposed that the regular consumption of wild Italian blackthorn fruit should increase the circulation of bioactive compounds, such as polyphenols, which could possibly improve the endogenous antioxidant system and protect tissues against oxidative stress damage induced by high-fat diet and hyperglycemia. Considering its beneficial properties, wild Italian blackthorn fruit can be potentially used to produce natural functional food, novel nutraceuticals, and it can also be employed in food processing.

**Author Contributions:** Investigation, L.P., R.R., F.V., A.V. and C.M.D.C.; Methodology, L.P., R.R., S.F., J.A., M.P. and C.M.D.C.; Supervision, D.C. and V.L.; Writing—original draft, L.P., R.R., F.V. and A.V. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Acknowledgments:** This study was supported by Institute of Biology and Agricultural Biotechnology of National Research Council (Italy), by Department of Agricultural, Environmental and Food Sciences, University of Molise (Italy) and by AgroBioTech Research Center (Slovakia), built in accordance with the project Building AgroBioTech Research Center ITMS 26220220180.

**Conflicts of Interest:** No conflict of interest was reported by the authors.
