**5. Conclusions**

In conclusion, both PSRE and PACN revealed antibacterial and antiinflammatory efficiency in periodontitis mimicking conditions. However, the combination of strong pathogen-selective antibacterial, antiinflammatory and gingival tissue protecting properties of PACN suggests this preparation as a potential candidate for treatment and prevention of periodontal disease.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2072-6643/11/11/2829/s1, Figure S1: The concentration-dependent toxicity of *Pelargonium sidoides* root extract (PSRE) and proanthocyanidins from PSRE (PACN) for rat gingival fibroblasts, Figure S2: E ffects of *Pelargonium sidoides* root extract (PSRE) and proanthocyanidins from PSRE (PACN) on human peripheral blood mononuclear cell viability, Figure S3: The effect of Pelargonium sidoides DC root extract (PSRE) and proanthocyanidins from PSRE (PACN) on Detection of apoptosis by staining bone-marrow derived macrophages (BMDM).

**Author Contributions:** Conceptualization, M.D., A.J., L.R. (Lia Rimondini), and N.S.; methodology, M.D., A.J., L.R. (Lia Rimondini), A.C., I.S., M.M.-K., E.M., L.R. (Lina Raudone); investigation, I.S., A.C., M.M.-K., G.L., E.M., R.B. (Rasa Bernotiene), E.V., L.R. (Lina Raudone), R.B. (Rasa Baniene), A.S.; data curation, I.S., A.C., M.M.-K., E.M., G.L., A.J.; writing—original draft preparation, A.J., M.D., A.C.; writing—review and editing, All authors; supervision, M.D., A.J., L.R. (Lia Rimondini), N.S.; funding acquisition, N.S., M.D., L.R. (Lia Rimondini).

**Funding:** This research is a part of the project PELARGODONT ("Engineering and functionalization of delivery system with *Pelargonium sidoides* biologically active substance on inflamed periodontal surface area") funded by a gran<sup>t</sup> (No. S-M-ERA.NET-17-2) from the Research Council of Lithuania, the State Education Development Agency of Latvia, and Italian Ministry of Education, University and Research.

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