## 4 Discussion  
As published in previous reports, the EO of the _Eucalyptus_ genus was described by a great quantity of 1,8-cineole (eucalypt). Current data are in accordance with those published by [PERSON] et al. [18] and [PERSON] et al. [26], who found that the principal chemical element of EGEO was eucalypt. The chemical composition of a diversity of other _Eucalyptus_ species have been reported [7; 19; 27] and are also in accordance with our data. Different percentages of eucalypt in _Eucalyptus globulus_ leaf EO have been shown: 53.7% in Tunisia, 14.5% in Germany, 33.6% to 66.7% in India and 71% in Brazil. The majority of EO extracted from _Eucalyptus_ trees contains at least 10% to as high as 97% eucalypt (1,8-cineole). Ecological position (Table 5), climatic conditions and extraction methods have been invoked as reasons for the chemical composition disparities and variations [18; 20]. Figure 3: Effect of EGEO at different doses (0.08, 0.2 and 0.4 \(\mu\)L/mL) in association with moderate heat processing (70 \({}^{\circ}\)C for 2 min) on the viability of _Saccharomyces cerevisiae_ cells in Orangina beverage during storage. The fungal growth was followed up to 6 days after the heat processing. HT: Heat treatment at 70 \({}^{\circ}\)C for 2 min; PG: Positive control or juice with synthetic antimicrobial additives (sodium benzoate and potassium sorbate); EGEO: _Eucalyptus globulus_ essential oil; CFU: Colony-forming unit. * significant difference (\(p<0.05\)) according to ANOVA one-way analysis followed by [PERSON]’s post hoc multiple comparison tests. A few investigations have been completed to study the antioxidant activity of different _Eucalyptus_ EO such as _E. globulus_[28; 34; 35; 36; 37; 30]. Our IC\({}_{50}\) values are not in agreement with those published for the DPPH radical scavenging method [34]. The scavenging activity on the DPPH radical reported as IC\({}_{50}\) value was 57 \(\mu\)g/mL for Tunisian EGEO, but this result is inferior as compared to the BHT value obtained with the same test (11.5 \(\mu\)g/mL) [34]. _E. tereticornis_ EO presented powerful DPPH, OH and O\({}^{2-}\) radical scavenging activity [35]. In opposition, _E. camalduncisis_ and _E. radiata_ EOs have been reported to display a medium DPPH scavenging effect [38]. This variance in antioxidant power may be related to the variation in chemical composition, distillation methods and environmental aspects, age of the trees, storage conditions and geo-climatic situations [12]. In addition, [PERSON] et al. [35] tested the _Eucalyptus_ EO and its three main oxygenated terpen (isopulegol, \(\beta\)-citronello and citronellal) for antioxidant and scavenging effect. The authors reported that the EO extracted from _Eucalyptus_ displayed medium to powerful antioxidant effect in terms of metal chelating (877.3% \(\pm\) 9.27% inhibition), DPPH radical (IC\({}_{50}\) = 425.4 \(\pm\) 6.79 mg/mL) and lipid peroxidation inhibition. This research revealed that _Eucalyptus_ EO leaves contain oxygenated monoterenes rich EO presenting antioxidant action. The chelating property on metal ions is one of the important mechanisms of antioxidant activity. _Eucalyptus_ EO showed a better chelating effect (8.43 \(\pm\) 0.03 mg/mL) on ferrous ions in comparison with standards (BHA = 104.73 \(\pm\) 7.30 mg/mL) and ascorbic acid = 140.99 \(\pm\) 3.13 mg/mL). Analysis of metal ion chelating activities revealed that all EOs extracted from _Eucalyptus_ species were capable of  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Plants** & **Country** & **Period** & **Method** & **Composition (\%)** & **Authors** \\ \hline \multirow{4}{*}{_E. globulus_} & \multirow{4}{*}{Spain} & \multicolumn{3}{c}{Hydrodistillation of leaves and small branches of the tree.} & **Eucalyptus\(\pm\) 63.81** & \multirow{4}{*}{[PERSON]} \\  & & & Certified as biological products to & & Aromadendherene = 3.68 & \multirow{4}{*}{ et al. [28]} \\  & & & be used in humans. & & & \\ \cline{5-5}  
chelating iron (II) in a dose-dependent way [9].