**4. Conclusions**

In this study, the composition of phenolic compounds in the leaf extracts of 18 different *H. acetosella* accessions was determined and how it contributed to their antioxidant and antibacterial activities. The antioxidant activity was significantly associated with the level of anthocyanins in the phenolic extracts. This study is the first to report the antibacterial activity of *H. acetosella* against both Gram-positive and Gram-negative bacteria. These results could be useful for exploring the potential of medicinal crops as a valuable resource for discovering new pharmaceutical drugs.

**Supplementary Materials:** The Supplementary Materials are available online. Figure S1: Ultra-high performance liquid chromatography (UPLC) 3D profiles of the 18 *H. acetosella* accessions. The numbers in the boxes correspond to the numbers in column 1 of Table 1. Figure S2: Agar-well diffusion test demonstrating inhibition zones against *S. aureus* and *P. aeruginosa* bacteria. All test were performed three replicates. Table S1: DPPH radical activity of 18 different *H. acetosella accessions*.

**Author Contributions:** Conceptualization, J.I.L. and J.R.; formal analysis, J.I.L., J.R., K.-S.S., and C.H.J.; investigation, D.-G.K., J.M.K., and S.H.K.; writing—original draft preparation, J.I.L., J.R. and C.H.J.; writing—review and editing, J.I.L. and S.-J.K.; supervision, J.-B.K.; project administration, S.-Y.K.; funding acquisition, J.-W.A. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was supported by the research program of Korea Atomic Energy Research Institute, Republic of Korea and the Radiation Technology R&D Program (NRF-2017M2A2A6A05018538) through the National Research Foundation of Korea, funded by the Ministry of Science and ICT.

**Acknowledgments:** We thank Philip Creed, from Edanz Group (https://en-author-services.edanzgroup.com/) for editing a draft of this manuscript.

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