## 3 Discussion  
More than 200 different components present in pure essential oils have been reported. These mixtures typically contain phenylpropanoic derivatives or terpen [16]. In general, gas chromatography (GC) is used for the analysis of volatile constituents present in essential oils, and liquid chromatography (LC) is used for the analysis of non-volatile constituents [17]. Usually, most essential oils are composed of volatile fractions, which contain monoterenes, sesquiterpenes, and their oxygenated derivatives, where aliphatic alcohols, esters, and aldehydes may also be present [18; 19]. The main compound found in the essential oil of _C. winterianus_ using the GC technique with mass spectrometry was geraion (3,7-dimethyl-2,6-octadian-8-oil) (42.13%), an acyclic monoterpenic alcohol in which biosynthesis occurs mainly in the cytosol of glandular trichomes via geranyl monophosphate (GP) through the action of a Nudix hydrolase [20; 21]. Secondarily, citronellal (17.31%) and citronellol (16.91%) were detected in median concentrations, in which biosynthesis is related to the expression of heterodimeric geranyl diphosphate synthases (GPPS-SSU) and plastid geranylgeranyl diphosphate (GGPP) [22]. Essential oils of _Cymbopogon_ spp. are diverse in chemical composition and have many bioactivities and potentials of great pharmaceutical and medicinal significance [23]. In this genus, it is possible to observe a remarkable variation in the composition and yield of the essential oil, which varies from 0.3% in _C. travancorensis_ to 1.2% in _C. martini_. The main components of citral essential oil \"a\" and \"b\" were detected in _Cymbopogon pendulus_, _C. flexuosus_, and _C. citratus_ with the largest in _C. citratus_. _Cymbopogon confertiforus_ and _C. nardus_ var. _contertiflorus_ present an essential oil with a high content of geraniol (67.7% and 46.0%, respectively), and another group including _C. nardus_ var. _nardus_, _C. nardus_ var. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Natural** & **Con. \(\underline{\text{\text{\text{\text{\text{\text{\text{\text{\text{\text{\text{ \text{\text{\text{\  
Java II, and C. winterianus_ have less geraniol in their essential oil (ranging from 20% to 25%) [24; 25]. Regarding the composition of the EOCw, the results obtained in the present study differ slightly from those already observed in the literature, according to which the proportion of citronellal (up to 40.23%) was higher than that of geraniol (up to 22.78%), with citronellol always having the third-highest proportion [26; 27]. In the study by [PERSON] et al. [28], it is possible to observe that the proportion of geraniol has a significant positive correlation (0.60) with the maximum temperature to which the plant is exposed. Studies that evaluated the cytotoxic effect of essential oils of species of the _Cymbopogon_ genus on mammalian cells showed that these are usually similar to that observed in the present study for C. _winterianus_ (LC\({}_{50}\) = 96.56 \(\mu\)L/mL) (Figures 2 and 5, Table 2) so that the LC\({}_{50}\) varies in the range of 50-300 \(\mu\)L/mL, where an LC\({}_{50}\)\(>\) 50 \(\mu\)L/mL is indicated as non-cytotoxic [29; 30]. In fact, in _Cymbopogon_ spp. with a similar proportion of constituents to that observed here in EOCW, a cytoprotective effect is observed [31]. In the literature, a great variation in the antioxidant capacity of EOCw can be observed (IC50 = 12. 66 \(\pm\) 0.56/743 \(\pm\) 18 \(\mu\)g/mL), especially with regard to its capacity to reduce the 2,2-diphenyl radical -1-picrylhydrazyl (DPPH), which may be related to its great variability in its composition [32; 33]. Essential oil of C. _winterianus_, as well as that of C. _citratus_, has already been shown to inhibit cytotoxicity in murine neutrophils through a mechanism not related to free radical scavenging [34]. The low cytotoxicity observed here (Figures 2 and 5, Table 2) is probably due to the absence of compounds known to be toxic to mammalian cells in EOCw (Table 1), such as citral [35].