**4. Conclusions**

This study showed that phenolic acids significantly protected endothelial cells against H2O2-induced oxidative damage by modulating NO, GSH, MDA, and ROS levels. Sinapic acid alleviated endothelial dysfunction by enhancing HO-1, NQO-1, GCLC, p-Akt, and p-eNOS expression levels, as well as activating Nrf2 nuclear translocation. Overall, these results illustrate that sinapic acid, which exists abundantly in cereals, spices, vegetables, oil seed crops, citrus, and berry fruits, has the potential as a treatment option for hypertension. However, further in vivo studies and clinical trials are needed to determine the underlying mechanism of action.

**Author Contributions:** Conceptualization and writing—original draft preparation: M.Y.; project administration: H.J.K.; methodology: H.H.; data curation: M.K. and Y.J.; writing—review and editing: H.L.; supervision: J.L. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the Rural Development Administration, grant number PJ01415004.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

**Conflicts of Interest:** The authors declare no conflict of interest.

**Sample Availability:** Not available.
