## 4 Discussion  
The yield of fresh leaves of _M. armillaris_ EO was estimated from the amount of oil mass obtained, with an average yield of 1.01 \(\pm\) 0.0003% (\(w/w\)), a poor yield compared to others reported in the literature for the species studied in Indonesia, which was 3.47% [30]. Figure 4: Chemical structure of geranyl acetate isolated from _Melaleuca armillaris_ essential oil. Figure 3: GC/MS chromatogram of the EO from the leaves of _Melaleuca armillaris_ in a 5% phenyl-methylpolysiloxane column. The yield obtained varies according to different parameters, such as the type of plant material, extraction methods, environmental conditions and geographical distribution, among others [31]. On the other hand, the results of the physical properties are similar to studies with other species of the same genus, such as _M. alternifolia_, which has a density of 0.885 g/mL and a refractive index of 1.482 [17; 32; 33]. In the chemical analysis of _M. armillaris_ EO, more than 99.92% of the total constituents of the sample volatile fraction were identified on the DB-5 ms chromatography column. The most frequently reported major constituents were oxygenated monoterpenes (77.01%), hydrocarbon monoterpenes (21.31%) and hydrocarbon sesquiterpenes (1.31%). Compared to other studies, it has been reported that _M. armillaris_, in some cases, reports constituents as terpene compounds and their corresponding alcoholic derivatives [34]. Another EO of _M. armillaris_ presented that the main compounds were 1,8-cineol (66.51%), \(\alpha\)-terpineol (8.83%), limonene (10.34%), \(\alpha\)-pinene (5.23%), myrcene (2.22%) and \(\beta\)-pinene (1.55%). Other studies reported similar compounds for the same species, indicating that 1,8-cineol is the major component (71.9-72.3%), followed by limonene (7.8-8.2%) and \(\alpha\)-pinene (6%) [35; 36]. Another study showed that the EO from Pakistan was rich in 1,8-cineole (33.93%), terpinene-4-ol (18.79%), limonene (10.37%) and B-pinene (6.59%) [37]. When compared with the literature results, the results of this study were also consistent in the overall range of percentages of major compounds. In contrast to our study, the study by [PERSON] et al. [38] on the EO of _Melaleuca leucadendron_, a species of the same family, reported that the main compounds found were \(\beta\)-eudesmol (15.8%), \(\alpha\)-eudesmol (11.3%), viridifol (8.9%) and guaioi (9.0%), respectively. [PERSON] et al. (2012) showed that the concentration of the major compound in _Melaleuca_ species was markedly low (3.6%) [39]. Finally, other studies reported that the essential oil of this species contained mainly caryophyllene oxide (43.8%), followed by (--)-spathulenol (9.7%) [40]. Regarding the geranyl acetate isolation, the results obtained are in agreement with those presented by [PERSON] et al. (2007) for \({}^{1}\)H NMR (CDCl\({}_{3}\); 400 MHz), 1.61 (3H, s), 1.69 (3H, s), 1.71 (3H, s), 2.07 (3H, s), 2.08-2.15 (4H, m), 4.60 (2H, d, J = 7 Hz), 5.09 (1H, t, J = 7 Hz), 5.35 (1H, t, J = 7 Hz); \({}^{13}\)C NMR (100 MHz, CDCl\({}_{3}\)), \(\delta\) (ppm): 171.5, 142.6, 132.2, 124.5, 118.6, 61.8, 39.9, 26.7, 26.1, 21.4, 18.1, 16.8 [41]. Previous NMR studies confirmed the presence of geranyl acetate, and the \({}^{13}\)C NMR spectra showed characteristic peaks associated with the presence of carbon. The peak at \(\delta\) = 170.89 represents the R-CO-OR group. The peaks at \(\delta\) = 142.00 and \(\delta\) = 131.62 represent carbons with unsaturated (double) bonds. The peaks at \(\delta\) = 123.72 and \(\delta\) = 118.35 have positive signs and represent carbon atoms with double bonds, corresponding to CH groups. The \({}^{1}\)H NMR spectrum showed characteristic peaks of the CH group located at \(\delta\) = 5.36-5.33, \(\delta\) = 5.10-5.07, \(\delta\) = 4.60-4.58 and \(\delta\) = 2.23 [19]. The results obtained were consistent with the findings of [PERSON] et al. (2005).