# Obtaining Aromatic Extracts from Portuguese
## 3 Results and Discussion
### Chemical Composition of T. mastichina L. Product
\begin{tabular}{l l l c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**No**} & \multirow{2}{*}{**Compound**} & \multirow{2}{*}{**LRI\({}^{\ast}\)**} & \multicolumn{8}{c}{**FR**} & \multicolumn{8}{c}{**DR**} & \multirow{2}{*}{**Sensory Descriptors**} \\ \cline{3-14}  & & & \multicolumn{2}{c}{**RT (min)**} & \multicolumn{1}{c}{**EX**} & \multicolumn{1}{c}{**EO**} & \multicolumn{1}{c}{**HY**} & \multicolumn{1}{c}{**EX**} & \multicolumn{1}{c}{**EO**} & \multicolumn{1}{c}{**HY**} & \multicolumn{1}{c}{**EX**} & \multicolumn{1}{c}{**EO**} & \multicolumn{1}{c}{**HY**} & \\ \hline
**38** &
\begin{tabular}{c} Citronlly1 \\ propionate \\ \end{tabular} & 1438 & 16.505 & - & - & tr & - & - & - & - & - & - & - & - & - & floral and green [37] \\ \hline
**39** &
\begin{tabular}{c} p-Farmesene \\ \end{tabular} & 1454 & 16.785 & - & - & tr & - & - & - & - & - & tr & - & - & woody, citrus and herbal [37] \\ \hline
**40** &
\begin{tabular}{c} a-Humulene \\ \end{tabular} & 1458 & 16.872 & - & - & tr & - & - & - & - & - & tr & - & - & woody [37] \\ \hline
**41** &
\begin{tabular}{c} Germacene D \\ \end{tabular} & 1483 & 17.317 & 0.8 & 0.1 & tr & - & - & - & 0.2 & 0.0 & - & - & - & - & - \\ \hline
**42** &
\begin{tabular}{c} Germacene B \\ \end{tabular} & 1498 & 17.595 & - & - & tr & - & - & - & - & - & - & - & - & woody, earthty and spicy [37] \\ \hline
**43** &
\begin{tabular}{c} Carybyhene \\ oxide \\ \end{tabular} & 1585 & 19.088 & - & - & tr & - & - & - & - & - & - & - & - & woody and herbaceous [9] \\ \hline
**44** &
\begin{tabular}{c} \(\gamma\)-Eudesmol \\ \end{tabular} & 1612 & 19.725 & - & - & tr & - & - & - & - & tr & - & - & - & - \\ \hline
**45** &
\begin{tabular}{c} a-Cadinol \\ \end{tabular} & 1630 & 20.292 & - & - & tr & - & - & - & - & - & - & - & herbaceous and woody [9,37] \\ \hline
**46** &
\begin{tabular}{c} Isopropyl1 \\ myristate \\ \end{tabular} & 1723 & 22.850 & - & - & - & - & - & - & - & tr & - & - & - & - \\ \hline
**47** &
\begin{tabular}{c} Isopropyl1 \\ palmitate \\ \end{tabular} & 1927 & 26.102 & - & - & - & - & - & - & - & tr & - & - & - & - \\ \hline \multicolumn{12}{c}{**Identified total**} & **90.0** & **99.7** & **99.8** & **100.0** & **100.0** \\ \hline \hline \end{tabular}   
Figure 2: Chromatographic profile of FR and DR _T. mastichina_ products analysed in GC-MS and identified as (**a**) EX obtained by SFE-CO\({}_{2}\), (**b**) EO extracted by HD and (**c**) HY provided from the HD method. The samples were analysed at different injection concentrations: (**a**) 2.5 g/L, (**b**) 0.01 g/L and (**c**) HY 0.1 g/L, respectively. The numbers at each peak represent the compounds identified in Table 2.  
The thymol chemotype is a natural phenolic monoterpene group synthesized by the transformation of \(\gamma\)-terpinene and \(p\)-cymene precursors. Both thymol and carvacrol isomers are indicated as the end of the biosynthetic chain catalysed by the two-step oxidation of \(\gamma\)-terpinene under the action of the cytochrome P450 enzyme (\(\gamma\)-terpinene synthase), which is able to modify the polarity of the compounds and make them more water-soluble [47]. Geranyl diphosphate (GPP) plays an important role in the initial chemical route, followed by the \(\alpha\)-terpineol intermediate [48]. Through a series of steps, the molecules are converted into \(\gamma\)-terpinene, which, by cyclization and carbonisation reactions, form the \(p\)-cymene molecule [3]. \(p\)-cymene is a by-product of the premature release of substrate from the active site [8; 47], and, by terpene synthase (TPS) activity, it produces thymol or carvacrol molecules when it reaches the last step of biosynthetic conversion. The TPS offers a wide range of ideal characteristics to modify the metabolic profile of terpen [3]. At the same time, the final products are formed directly via \(\gamma\)-terpinene hydroxylation [47; 48]. Moreover, \(\alpha\)-thujene, \(\beta\)-myrorene, 3-carene and \(\beta\)-caryophyllene had some influence on the chemical profile of _T. mastichiua_ plant, mainly in DR samples.