**4. Conclusions**

In this study, we evaluated the protective e ffect of LJSF4 against UVB-induced photodamage by in vitro and in vivo models. Treatment with LJSF4 prior to UVB exposure considerably protected the HaCaT cells against ROS generation. In addition, the ROS, the cell death, the nitric oxide, and the lipid peroxidation induced by UVB radiation in zebrafish were reduced by the addition of LJSF4. This study suggested the potential use of LJSF4 from *S. japonica* for the treatment of UVB-caused skin damage, which indicated that LJSF4 has a grea<sup>t</sup> potential to be used in cosmetic products as an e ffective natural anti-UVB agent.

**Author Contributions:** Conceptualization, funding acquisition and Supervision, X.F.; methodology, investigation, data curation, W.S., L.W. and L.N.; project administration, X.F., J.X. and X.G.; sample preparation and collection, D.D.; formal analysis and writing, W.S. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by National Key R&D Program of China (Grant No. 2018YFD0901104), and the Major Scientific and Technological Innovation Project of Shandong Province (Grant No. 2019JZZY020613).

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