## 2 Results and Discussion
### OC Kappa Induced an Increase in Total Essential Oils and a Reprogramming of Terpenoid Metabolism
Thus, the increase in terpenoids induced by OC kappa may enhance defense against insects and microbes in _Eucalyptus_ trees. In addition, six terpenoids were synthesized _de novo_ the leaves of treated _Eucalyptus_ trees. The monoterreponoids of the limonene family, carene and \(\alpha\)-terpinene, and that of pinene family, fenchene were synthesized _de novo_ in treated trees. The sequiterpenoid of cadinence family, \(\gamma\)-maaliene, that of isoledene family, spathulenol, as well as the monoterreponid related to camphenol, \(\alpha\)-camphenolic aldehyde, were also synthesized _de novo_ in treated _Eucalyptus_ trees. The newly synthesized terpenoids reached levels ranging from 3 to 9 \(\mathrm{\SIUnitSymbolMicro g}\)-\(\mathrm{g}^{-1}\) of FT (Table 3). Regarding terpenoids synthesized _de novo_ in response to OC kappa, it has been shown that the monoterpene carene has an insecticidal activity against the maize weevil _Sitophilus zeamaise_ (Coleoptera) [24]. In addition, the sesquiterpenoid spathulenol had a repellent activity against the yellow fever mosquitos _Aedes aegypti_ and _Anopheles stephensi_[25]. Thus, terpenoids that were \begin{table}
\begin{tabular}{c c c c} \hline \multirow{2}{*}{**Compound**} & \multicolumn{2}{c}{**Level in Control Trees**} & \multirow{2}{*}{**Level in Treated Trees**} & \multirow{2}{*}{**\% of Increase**} \\  & **(\(\mathrm{\SIUnitSymbolMicro g}\)-\(\mathrm{g}^{-1}\) FT)** & **(\(\mathrm{\SIUnitSymbolMicro g}\)-\(\mathrm{g}^{-1}\) FT)** & \\ \hline Silvestrene & \(142\pm 7\) & \(419\pm 21\) & 195 \\ \(\alpha\)-Phellandrene & \(9\pm 0.7\) & \(27\pm 2.2\) & 193 \\ \(\gamma\)-Terpinene & \(9\pm 0.7\) & \(22\pm 1.8\) & 151 \\ Limonene oxide & \(7\pm 0.6\) & \(12\pm 1\) & 70 \\ \(\beta\)-Pinene & \(28\pm 2.2\) & \(66\pm 5.3\) & 135 \\ \(\gamma\)-Cadinene & \(4\pm 0.3\) & \(5\pm 0.4\) & 44 \\ Aromadendrene & \(180\pm 9\) & \(267\pm 13.4\) & 49 \\ Viridiflorene & \(39\pm 3.1\) & \(82\pm 6.6\) & 110 \\ \(\alpha\)-Gurjunene & \(33\pm 2.6\) & \(208\pm 17\) & 529 \\ \(\gamma\)-Gurjunene & \(16\pm 1.3\) & \(78\pm 6.3\) & 390 \\ \(\alpha\)-Guaiene & \(1\pm 0.04\) & \(6\pm 0.5\) & 1041 \\ Myrcene & \(42\pm 3.4\) & \(53\pm 4.3\) & 26 \\ \hline \end{tabular}
\end{table} 
Table 2: Level of terpenoids that increased in leaves of _Eucalyptus_ trees treated with OC kappa. \begin{table}
\begin{tabular}{c c c} \hline \multirow{2}{*}{**Compound**} & \multirow{2}{*}{**Type**} & \multirow{2}{*}{**Level in Treated Trees (\(\mathrm{\SIUnitSymbolMicro g}\)-\(\mathrm{g}^{-1}\) FT)**} \\ \hline Carene & Monoterpene & \(4\pm 0.3\) \\ \(\alpha\)-Terpinene & Monoterpene & \(3\pm 0.3\) \\ \(\alpha\)-Fenchene & Monoterpene & \(8\pm 0.6\) \\ \(\gamma\)-Maaliene & Sesquiterpene & \(9\pm 0.8\) \\ Spathulenol & Sesquiterpene & \(5\pm 0.4\) \\ \(\alpha\)-Camphenolic aldehyde & Monoterpene & \(6\pm 0.4\) \\ \hline \end{tabular}
\end{table} 
Table 3: Level of _de novo_ synthesized terpenoids in leaves of _Eucalyptus_ trees treated with OC kappa. synthesized _de novo_ in response to OC kappa have repellent and insecticidal activities _in vitro_ suggesting that treated trees may have enhanced defenses against insects. Thus, treatment with OC kappa induced an increase and reprogramming of terpenoid metabolism in _E. globulus_ trees since the level of six terpenoids decreased, the level of 12 terpenoids increased and six terpenoids were synthesized _de novo_ in response to OC kappa. OC-Kappa Induced Reducing Redox Status Change the Level of Total Essential Oils and Induced Terpenoid Synthesis Reprogramming  
The level of total essential oils decrease in trees treated with CHS-828, an inhibitor of NAD(P)H synthesis, auranofine, an inhibitor of TRR activity, lycorine an inhibitor of ASC synthesis, and BSO, an inhibitor of GSH synthesis, and with OC kappa from 5.5 mg\(\cdot\)g\({}^{-1}\) of FT to 5.2, 4.9, 5 and 3.5 mg\(\cdot\)g\({}^{-1}\) of FT which correspond to decreases of 34%, 63%, 53% and 100%, respectively (Figure 2).