## 2 Results
### Composition of EOs
GC analysis performed by an enantioselective GC column allowed for the detection of seven \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline  & & & \multicolumn{8}{c}{**Oregano Subspecies/Hybrid**} \\ \cline{4-10}
**No.** & **Compound Name** & **Class** & \multicolumn{4}{c}{_Origanum vulgare ssp._} & \\ \cline{4-10}  & **Compound** & **Class** & \multicolumn{4}{c}{_viridulum \(\times\)_} & \multicolumn{4}{c}{_Origanum hexeloeticum L._} \\ \cline{4-10}  & & & & & & & & & \\  & & & & & & & & & \\  & & & & & & & & & \\  & & & & & & & & & \\ \hline
30 & \(\gamma\)-cadinene & SH & - & - & - & 0.15 & 0.12 & 0.10 & 0.08 & 0.12 \\
31 & \(\delta\)-cadinene & SH & - & - & - & 0.47 & 0.39 & 0.39 & 0.33 & 0.47 \\
32 & unknown & SH & - & - & - & 0.19 & 0.18 & 0.17 & 0.14 & 0.24 \\ \hline \multicolumn{10}{c}{**Total content of compounds grouped in chemical classes**} \\ \hline Monoterpene Hydrocarbons (MH) & 11.71 & 13.03 & 13.88 & 31.74 & 23.94 & 37.93 & 28.11 & 26.58 \\ Oxygenated Monoterpenes (OM) & 85.42 & 84.50 & 83.59 & 63.13 & 71.44 & 55.80 & 68.02 & 66.46 \\ Sesquiterpene Hydrocarbons (SH) & 2.66 & 2.25 & 2.33 & 5.13 & 4.61 & 6.27 & 3.87 & 6.85 \\ Others & 0.22 & 0.23 & 0.20 & - & - & - & - & - \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Cont._  
Figure 1: Principal component analysis (PCA) biplot of the first two PCs obtained in the dataset of the chemical compositions of EOs of the hybrid _Origanum vulgare ssp. viridulum \(\times\) Origanum vulgare ssp. hirthum_ (CAR1, CAR2, CAR3) and of the subspecies _Origanum hexeloeticum_ L. (THY1, THY2, THY3, THY4, THY5). pairs of enantiomers in four monoterepene hydrocarbons, \(\alpha\)-thujene, \(\alpha\)-pinene, \(\beta\)-pinene, \(\alpha\)-phellandrene and three oxygenated monoterepenes, linalool, terpinen-4-ol and \(\alpha\)-terpineol. This last compound was not quantified in the GC analysis with an achiral column (Table 1) because its level was lower than 0.05%, but it was included in the enantioselective analyses because it was possible to accurately determine its two enantiomers. The analysis of the isolates obtained from the dried leaves and flowers by HS-SPME allowed for the determination of a higher number of enantiomeric pairs than in the analysis of the EOs, because the former isolates were more concentrated. In the case of \(\alpha\)-thujene, it was not possible to identify the two enantiomers, due to unavailability of commercial standard pure compounds and lack of appropriate information from the literature of chromatographic data. The results obtained for both the dried aerial parts and EOs showed that the enantiomeric distribution was the same in plants belonging to the subspecies _Origanum heracleoticum_ L. and the hybrid _Origanum vulgare ssp. viridulum \(\times\) Origanum vulgare ssp. hitrum_, and it was not affected by the different environments of cultivation. Only in the case of the distribution of linalool enantiomers, as determined in the dried plant materials in one sample (CAR3), was there a slight difference in the distribution of enantiomers observed, with a 17% level of the S enantiomer instead of the 8-11% level observed in the other samples. Moreover, results obtained from the dried plant material showed less variability when compared to those obtained from the EOs. This could partly be due to the more concentrated isolate analyzed in the former case. Enantiomeric distribution as determined in the dried plant material was generally similar to that observed in the EOs, with some minor differences. For instance, the distribution of \(\alpha\)-pinene enantiomers was, on average, 5:95 and 10:90 in the EOs and plant material, respectively; the distribution of \(\beta\)-pinene was 81:19 and 73:27; the distribution of terpinene-4-ol was 61:39 and 51:49; and the distribution of \(\alpha\)-terpineol was 0:100 and 9:91. In all cases, a slightly higher enantiomeric excess was observed in the EOs than in the isolates from dried plant material.