## 4 Discussion
Another study reported that the antioxidant action of phytochemicals in lemon eucalyptus oil may be due to their redox activities of the phenolic compounds and oxygenated terpen and that make them good reducing, scavenging and chelating EO [8]. One of the probable modes of action of the antioxidative effect is the chelation of transition metals. There are very limited published studies about the antioxidant property of eucalypt as the principal chemical compound of the EGEO [36]. Consequently, antioxidant property detected for the volatile oil could be linked to the remaining compounds [35]. [PERSON] et al. [37] revealed a medium antioxidant property by preventing the oxidative alteration of linoleic acid (20%) for 12 days for the EO of _Eucalyptus canalduensis_. Instead, EOs extracted from aerial parts of _Eucalyptus canalduensis_, growing wild in different regions of Sardinia Island (Italy), have exhibited an _in vitro_ antioxidant potential that varied between 0.5 and 5.8 mM [38]. The mode of action involved in the lipid peroxidation and inhibition of DPPH assay is not analogous, thus, the results of the current experiment are not similar to those formerly published by [PERSON] et al. [37] and [PERSON] et al. [38] because the positive controls and units used in both assays for the determination of the IC\({}_{50}\) values are not identical. Numerous published reports have assessed and confirmed the _in vitro_ antibacterial, anti-yeast and antifungal potential of EGEO against a varied collection of pathogens [39,40]. For example, _Eucalyptus citriodora_ EO has been demonstrated to have a wide range of anti-yeast action. Moreover, _Eucalyptus urophylula_ and _Eucalyptus camaldulensis_ EOs are also recognized for their microbial inhibitory effect [38]. Though much research has been dedicated to the antifungal and anti-yeast effects of EGEO [40], only a limited number of studies have estimated their bio-activity against foodborne bacteria and fungi [7]. [PERSON] et al. [41] reported 85.8% of eucalypt in EGEO from Montenegro and demonstrated its important and significant effect in the inhibition of different yeast and bacteria growth. Furthermore, another study [18] revealed powerful antiviral, antiseptic and antimicrobial activities of eight EGEOs from Tunisia. The microbial inhibitory action of EGEO has been shown to diverge considerably within microorganisms and species. The higher antiseptic potential could be directly linked to their main chemical constituents detected in the EGEO (such as eucalypt and \(\alpha\)-pinene) or with the interaction among the minor and major components [18]. Previously published studies revealed that Gram-positive strains are more vulnerable than Gram-negative bacteria; the inhibitory effect against yeasts (_C. albicans_ and _S. cerevisiae_) and fungi (_Aspergillus_, _Mucor_, and _Penicillium_ species) has also been investigated [7]. According to one of the reports, _Eucalyptus odorata_ volatile oil presented the strongest _in vitro_ inhibitory effect against micro-organisms and _Eucalyptus bicostata_ EOs possess the greatest antiviral action [18]. The EGEO vapor could be extremely active against food spoilage microorganisms in minor doses in comparison with the liquid diffusion, thus producing less influence on the organoleptic and sensorial food properties [42]. Hence, estimating the _in vitro_ antifungal and antibacterial actions of EGEO vapor might open up a promising dimension with many possible uses, especially in the food industry. Current data obtained by both vapor diffusion and agar disc diffusion tests were not similar. The efficiency of the EGEO had previously been described but their use in the vapors phase requires an advanced approach [20]. This could be related to the variance in the chemical composition profile of the vapors and liquid oil because the oil must be enriched in terms of its volatile compounds [7].