## 2 Results and Discussion
### Chemical Composition of Essential Oils and Hydrolats by GC-MS  
Table 1 shows the chemical composition by GC-MS of the EOs and EWs summarized in Table 3 (see experimental section). Overall, 10 monoterepne hydrocarbons, 19 oxygenated monoterepenes, 2 sesquiterpene hydrocarbons, 2 aromatic monoterepenes (one of which oxygenated), 1 ester, 4 ketones, 1 aldehyde and 5 alcohols were identified. Some of the main molecules detected in the EWs and EOs are reported in Figure 1. Relative abundance of each of the molecules identified by GC-MS was calculated as a percentage of the peak area on the total area of the identified peaks. Peak areas from the total ion current were normalized by the use of the area of internal standard (tridecane). Figure 1: Chemical structure of some of the most abundant molecules in the EWs and EOs. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**n\({}^{\circ}\)**} & \multirow{2}{*}{**Compound**} & \multirow{2}{*}{**RL\({}_{\text{lat}}\)**} & \multirow{2}{*}{**RL\({}_{\text{lat}}\)**} & \multicolumn{10}{c}{**Hydromolosis (Area \%)**} & \multicolumn{10}{c}{**Ensential Ohio (Area \%)**} \\ \cline{4-14}  & & & **1-16-EW** & **2-4-EW** & **-14-EW** & **-14-EW** & **-1-27-EW** & **-1-16-EW** & **-1-16-CO** & **2-4-CO** & **3-4-CO** & **4-16-EW** & **-1-16-F-CO** \\ \hline \multicolumn{14}{c}{**Aromatic Monoterspenses**} \\
24 & \(p\)-\(\gamma\)-mence & 1455 & 1455 & - & - & - & - & - & 0.03 & 0.04 & 0.02 & 0.03 & 0.04 & 0.03 \\ \hline \multicolumn{14}{c}{**Oxygenated Aromatic Monoterspenses**} \\
41 & \(p\)-\(\gamma\)-mence & 1455 & 1455 & - & - & - & - & - & 0.03 & 0.04 & 0.02 & 0.03 & 0.04 & 0.03 \\ \hline \multicolumn{14}{c}{**Oxygenated Aromatic Monoterspenses**} \\
41 & \(p\)-\(\gamma\)-mence & 0.06 & 0.11 & 0.08 & 0.10 & 0.10 & 0.08 & - & - & - & - & - & - \\ \hline \multicolumn{14}{c}{**Galaxy**} \\
41 & \(p\)-\(\gamma\)-mence-sd & 1857 & 18690 & 0.06 \(\pm\) & 0.11 \(\pm\) & 0.08 & 0.10 \(\pm\) & 0.08 & - & - & - & - & - & - \\ \hline \multicolumn{14}{c}{**Galaxy**} \\
4 & \(\text{isomally-acetate}\) & 1125 & 1126 & - & - & - & - & - & 0.04 & - & - & - & 0.03 & 0.05 \\ \hline \multicolumn{14}{c}{**Ketenes**} \\
5 & \(\text{hepta-4-core}\) & 1132 & - & 0.21 & 0.22 & 0.20 & 0.23 & 0.20 & 0.27 & 0.24 & 0.20 & 0.25 & 0.24 & 0.22 & 0.22 \\ \hline \multicolumn{14}{c}{**Ketenes**} \\
5 & \(\text{hepta-4-core}\) & 1132 & - & 0.21 & 0.22 & 0.20 & 0.23 & 0.20 & 0.27 & 0.24 & 0.20 & 0.25 & 0.24 & 0.22 & 0.22 \\ \hline \multicolumn{14}{c}{**0.06**} \\
5 & \(\text{hepta-4-core}\) & 1132 & - & - & - & - & - & 0.06 & 0.08 & 0.04 & 0.04 & 0.04 & 0.04 & 0.05 \\ \hline \multicolumn{14}{c}{**0.06**} \\
6 & \(\text{hepta-3-core}\) & 1161 & 1163 & 0.05 \(\pm\) & 0.06 \(\pm\) & 0.06 \(\pm\) & 0.07 \(\pm\) & 0.05 \(\pm\) & 0.08 & 0.07 \(\pm\) & 0.06 & 0.07 & 0.06 & 0.06 & 0.07 \\ \hline \multicolumn{14}{c}{**0.07**} \\
9 & \(\text{hepta-2-core}\) & 1190 & 1185 & 0.12 \(\pm\) & 0.16 \(\pm\) & 0.14 \(\pm\) & 0.16 \(\pm\) & 0.13 \(\pm\) & 0.16 \(\pm\) & 0.12 \(\pm\) & 0.11 & 0.14 & 0.14 & 0.12 & 0.11 \\ \hline \multicolumn{14}{c}{**0.08**} \\
19 & \(\text{hepta-4-core}\) & 1346 & 1338 & 0.04 \(\pm\) & - & - & - & - & - & - & - & - & - & - \\ \hline \multicolumn{14}{c}{**0.08**} \\
22 & \(\text{nonval}\) & 1465 & 1401 & - & - & - & - & - & - & - & - & - & - & - \\ \hline \multicolumn{14}{c}{**0.08**} \\
10 & 3-mebly/bunMonoterpene hydrocarbons (MH): these terpenes were present in the EO samples with relative abundances between 6.74% and 10.76%. Limonene was the most abundant MH, with similar percentages in all the EOs (3.00-4.65%). Different abundances of the other MHs were pointed out for different _Eucalyptus_ species: in _Eucalyptus parvula_, similar amounts of \(p\)-cymene and \(\alpha\)-pinene were detected, followed by lower amounts of \(\gamma\)-terpinene and \(Z\)-ocimene. In _Eucalyptus cinerea_, similar amounts of \(\alpha\)-pinene and Limonene were detected, followed by lower amounts of \(p\)-cymene, \(\beta\)-myrcene, \(\beta\)-pinene and \(Z\)-ocimene.