## 3 Results and Discussion  
### Glucosinolates and Volatiles  
UHPLC-DAD-MS/MS analysis of _I. semperviens_ revealed the presence of five (5) desulfoGSLs, dominated by GSLs derived from methionine (homoMet) and chain elongated methionine (dihomoMet), but also contained GSLs derived from Phe and Trp (Table 2, Figures 1 and S1). The main GSLs originating from methionine biosynthesis with chain lengths C3-C4 were 3-(methylsulfonyl)propyl GSL (glucoiberin, 73), 3-(methylsulfonyl)propyl GSL (glucoibervirin, 95), and 4-(methylsulfonyl)butyl GSL (glucoercin, 84). Benzyl GSL (glucotropaeolin, 11) was the only arylaliphatic GSL identified, while 4-methoxyindol-3 ylmethyl GSL (4-methoxyglucobrassicin, **48**) was the only indolic type GSL; both were present in traces. Identification of desulfoGSLs was based on their m/z values and retention times, as well as the MS\({}^{2}\) spectra that contained the fragments, which enabled the confirmation of the structures identified (Figure S2). The MS\({}^{2}\) spectrum of methylsulfinylalkyl dGSL **d73** showed the fragment m/z 302 from a neutral loss of CH\({}_{3}\)SOH from the sodium adduct, while the MS\({}^{2}\) spectrum of methylsulfanyl analogue **d95** showed only fragments of sodium adducts with anhydroglucose and thioglucose due to the low polarity of the side chain. Additionally, the fragment formed by the loss of oxidized thioglucose (m/z 212) that is characteristic of this type of dGSL was also observed for **d95**[33]. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**No. \({}^{*}\)**} & **Glucosionate (GSL)** & \(\mathbf{t_{R}}\) & \multirow{2}{*}{**[M + Na]\({}^{*}\)**} & \multicolumn{4}{c}{**Glucosionate Content**} \\  & **(Trivial Name)** & & & & **(\(\mu\)mol/g DW)** & & \\ \cline{5-8}  & & & & & **Seed** & **Stem** & **Leaf** & **Flower** \\ \hline \multirow{3}{*}{**73**} & HomoMet-derived & & & & & & & \\  & 3-(Methylsulfinyl)propyl GSL & 1.14 & 366 & 5.52 \(\pm\) 0.21 & 6.94 \(\pm\) 0.09 & 35.37 \(\pm\) 1.13 & 19.76 \(\pm\) 0.97 \\  & (glucoiberin) & 5.50 & 350 & 18.51 \(\pm\) 0.18 & 11.20 \(\pm\) 0.54 & 1.12 \(\pm\) 0.07 & 2.88 \(\pm\) 0.10 \\  & (glucoibervirin) & & & & & & \\ \hline \multirow{3}{*}{**84**} & DihomoMet-derived & & & & & & \\  & 4-(Methylsulfinyl)butyl GSL & 6.40 & 364 & tr & tr & n.d. & n.d. \\ \hline \multirow{3}{*}{**11**} & Phe-derived & & & & & & \\  & Benzyl GSL (glucotropaeolin) & 6.50 & 352 & n.d. & tr & n.d. & tr \\ \hline \multirow{3}{*}{**48**} & Trp-derived & & & & & & \\  & 4-Methoxyindol-3-ylmethyl & & & & & & \\  & GSL (4-methoxyglucobrassicin) & & & & & & \\ \hline \multicolumn{8}{c}{Total (\(\mu\)mol/g DW)} & \multicolumn{4}{c}{24.03 \(\pm\) 0.39} & 18.14 \(\pm\) 0.63 & 36.49 \(\pm\) 1.20 & 22.64 \(\pm\) 1.07 \\ \hline \hline \end{tabular} \({}^{*}\) No.—numbers are related to the glucosionate number given in the review paper by [PERSON] et al. [15], and the structures are shown in Figure 1. All chromatograms are given in Figure S1, while MS\({}^{2}\) spectra are given in Figure S2. DW—dry weight; tr—traces \(<\) 0.01 \(\mu\)mol/g DW; n.d.—not detected. The data are expressed as the mean value \(\pm\) standard error (n = 3). homo—the higher homologue of a specified amino acid.  
\end{table} 
Table 2: Glucosinolate content in _Iberis sempercirens_. Figure 1: Structures of the GSLs identified in _Iberis sempercirens_ (see Table 1). The more lipophilic 3-(methylsulfonyl)propyl GSL **95** was the major GSL in seeds (18.51 umol/g DW) and stems (11.20 umol/g DW). Traces of the higher C4 homologue, GSL **84**, were also detected in the same plant parts. GSL **73**, the oxidized form of **95**, was found at the highest level in the leaves of _I. sempervirens_, with 35.37 umol/g of DW, followed by 19.76 umol/g of DW in the flowers. Phe-derived GSL **11** was identified in this species for the first time, as was Trp-derived GSL **48**. These types of GSLs found at low levels are not ubiquitous for the _Iberis_ genus (Table 1).