## 4 Conclusions  
In summary, this is the first extensive study that focused on the chemical compositions and biological activities of seed and cone EOs from Greek fir. _Abies cephalonica_ seeds are a valuable source of EO and possess an intriguing, fresh, forest-like scent, while the EO from cone scales contains relatively fewer volatile compounds. While the quantitative and qualitative makeup compositions of the tested seed and cone EOs differ, they both primarily consist of monoterpene hydrocarbons. The seed EO is predominantly characterized by its high limonene content, while the cone EO is composed of \(\alpha\)-pinene, \(\beta\)-pinene, and limonene. Notably, the significant presence of the levorotatory form of these main terpen is a distinctive feature of _Abies_ species. The results indicate that the EOs derived from _Abies cephalonica_ seeds and cone scales exhibit no adverse effects on human skin fibroblasts and keratinocytes when used at low concentrations and cultured for 24 h. Furthermore, the tested EOs, especially those from the cones, have promising antimicrobial properties, which could offer a compelling therapeutic option, particularly at a time when bacterial resistance to conventional antibiotics is on the rise. Surprisingly, the seeds of the Greek fir tree can serve as an excellent source of essential oil and enantiomerically pure natural limonene. In the current era of natural and organic product trends, this rich source of EO and (S)-limonene might serve as a viable alternative to synthetic fragrance compositions. However, the usage of Greek fir essential oil as a raw material in cosmetics needs to be controlled due to the high content of limonene, which is one of the volatile allergens according to European Union regulations. This research material is the first study on the chemical compositions and biological properties of essential oils from Greek fir.  
**Supplementary Materials:** The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app132413238/s1](https://www.mdpi.com/article/10.3390/app132413238/s1)]([https://www.mdpi.com/article/10.3390/app132413238/s1](https://www.mdpi.com/article/10.3390/app132413238/s1)), details of gas chromatograms of EOs and fractions of seed EO as well NMR-spectra of seed EO fractions see the Supplementary Materials: Section S1.  
**Author Contributions:** Conceptualization, A.W.-B.; methodology, experiments, and analysis, A.W.-B., L.S. and P.K.; writing--original draft, A.W.-B., E.M., L.S. and P.K.; writing--review and editing, A.W.-B., E.M., P.K. and L.S.; visualization, A.W.-B. and L.S. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research received no external funding.  
\begin{table}
\begin{tabular}{l c c c c} \hline \hline
**Substance** & **MIC 2** & **MBC 3** & **MBC/MIC Ratio 4** & **Effectiveness** \\ \hline _Staphylococcus aureus_ ATCC 29213 & & & & \\ Seed EO & 3.91 \(\pm\) 0.00 A & 15.63 \(\pm\) 0.00 A & 4 & Bactericidal \\ Cone EO & 0.49 \(\pm\) 0.00 A & 0.81 \(\pm\) 0.28 A & 2 & Bactericidal \\ Thym1 & 1.90 \(\pm\) 0.00 B & 3.80 \(\pm\) 0.00 B & 2 & Bactericidal \\ Gentamicin sulfate 1 & 0.31 \(\pm\) 0.00 B & 0.61 \(\pm\) 0.00 B & 2 & Bactericidal \\ \hline _Escherichia coli_ ATCC 8739 & & & & \\ Seed EO & 7.81 \(\pm\) 0.00 A & 31.25 \(\pm\) 0.00 A & 4 & Bactericidal \\ Cone EO & 1.63 \(\pm\) 0.56 A & 3.91 \(\pm\) 0.00 A & 2 & Bactericidal \\ Thym1 & 4.07 \(\pm\) 1.41 B & 8.13 \(\pm\) 2.81 B & 2 & Bactericidal \\ Gentamicin sulfate 1 & 0.51 \(\pm\) 0.18 B & 1.22 \(\pm\) 0.00 B & 2 & Bactericidal \\ \hline \hline \end{tabular}  
* Positive controls; 2 MIC—minimum inhibitory concentration; 3 MBC—minimum bactericidal concentration; 4 MBC/MIC ratio \(\leq\) 4 – bactericidal; MBC/MIC ratio \(>\) 4 –bacteriostatic; \(\mu\)L/mL; 8 ug/mL.  
\end{table}
Table 3: The antibacterial effectiveness of the _Abies cephalonica_ seed and cone scale essential oils (seed EO, cone EO) against reference strains.