**4. Conclusions**

In general, Gram-positive bacteria had higher resistance against tested compounds than Gram-negative bacteria. Fluorine, as the most electronegative element, modifies electron distribution which can diversify cell surface permeability leading to cell death. Since the experiment has proven that synthesized compounds are inactive as inhibitors of tyrosinase, a docking study has been performed and has indicated that the compound with the dimethoxyphenyl ring could be potent as an inhibitor of phosphodiesterase.

**Author Contributions:** Conceptualization, M.M.; methodology, H.B., M.M., V.R., I.S., M.L., M.K. and V.P.; software, V.R.; validation, M.M., V.P. and V.R.; formal analysis, V.R. and V.P.; investigation, H.B., I.S., M.L. and M.K.; resources, M.M.; data curation, M.M., V.P., and V.R.; writing—original draft preparation, V.P.; writing—review and editing, V.P., V.R.; visualization, M.M.; supervision, V.P.; project administration, V.R.; funding acquisition, V.P.

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

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