## 3 Results and Discussions  
### Essential Oil Composition Analysis  
Hydrodistillation of _A. secundiramea_ Biv. subsp. secundiramea_ leaves (L) gave a pale-yellow oil, (yield (0.46%). Only four components were recognized, representing 99.2% of the total composition. The metabolites are listed in Table 1 according to their retention indices on an HP-5 MS column. All the four compounds were chrysantenyl derivatives with (_E_)-chrysanthenyl acetate (Figure 1) (91.5%) as main compounds, followed by chrysanthenone (4.2%), (_E_)-chrysanthenol (3.3%), and a small amount of (_Z_)-chrysanthenol (0.2%). Quite amazingly, hydrodistillation of _A. secundiramea_ Biv. subsp. secundiramea flowers (F) gave an oil (yield 1.55%) containing only (_E_)-chrysanthenyl acetate (100.0%). The positive optical rotation of the oil determined its absolute configuration as (+)-(_E_)-chrysanthenyl acetate, whose synthesis starting from (+)-verbenoe has been previously described [15]. The chromatograms of the two oils (L and F) are reported in Figure 2, whereas Figure 3 shows the \({}^{1}\)H-NMR spectrum of the oil from flowers. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \(\mathbf{K_{i}}\)a  & \(\mathbf{K_{i}}\)b  & \(\mathbf{L}\)c  & \(\mathbf{F}\)\% & \(\mathbf{L}\)\% \\ \hline
1114 & 1684 & (Z)-Chrysanthenol & 1,2 & & 0.2 \\ \hline
1126 & 1521 & Chrysanthenone & 1,2 & & 4.2 \\ \hline
1163 & 1764 & (\(E\))-Chrysanthenol & 1,2 & & 3.3 \\ \hline
1236 & 1585 & (\(E\))-Chrysanthenyl acetate & 1,2 & 100.0 & 91.5 \\ \hline
**Total** & & **100.0** & **99.2** \\ \hline \end{tabular}
\end{table} 
Table 1: Composition of essential oils from _A. secundiramea_ Biv. ssp. _secundiramea_ (Asteraceae). Figure 1: Structure of (+)-(\(E\))-chrysanthenyl acetate. Figure 2: Chromatograms of the essential oils of _A. secundiramea_ flowers (**F**) and leaves (**L**). Some interesting considerations can be made by comparing our results with those reported in the literature for _A. maritima_, _A. cupaniana_, and _A. secundirramea_, belonging to the same clade. A component analysis on the essential oil of six accessions from Corsica and twelve accessions from Sardinia of _A. maritima_ divided them into two groups. In the first one, comprising the populations of Corsica and west Sardinia, 6-methylhept-5-en-2-one was identified as the main component. Several chrysanthenyl derivatives were also present, but (_E_)-chrysanthenyl acetate was totally absent. On the other hand, the populations from east Sardinia, belonging to the second group, were characterized by the high quantity of (_E_)-chrysanthenyl acetate and other chrysanthenyl derivatives [16]. Subsequent investigations on six accessions of _A. maritima_ from Tuscany [17] and of five population collected on the Adriatic coast of Italy [18] confirmed the high variability of the occurrence of (_E_)-chrysanthenyl acetate ranging from 0 to 55.6% and from 0 to 28.1%, respectively. On the other hands, the analysis of the oil isolated from the aerial parts of _A. cupaniana_ showed a very poor content of chrysanthenyl derivatives with (_E_)-chrysanthenyl acetate completely absent [4]. Quite recently, the analysis of the essential oil of the aerial parts _A. secundirramea_, collected in the western part of Sicily, showed the presence of several irregular oxygenated monoterenes with (_Z_)-chrysanthenyl acetate (9.9%) and (_E_)-chrysanthenyl acetate (7.7%) among the main compounds [3]. Other species of _Anthemis_ showing a good occurrence of (_E_)-chrysanthenyl acetate were _A. cretica_ ssp. _messanensis_ from Sicily (28.8-24.2%) [19] and _A. montana_ from Serbia (11.3%) [20]. In Table 2, the occurrence of (_E_)-chrysanthenyl acetate in different species is reported.