## 3 Results and Discussion
### Glucosinolates and Volatiles
The _Iberis_ genus appears to be limited to the biosynthesis of C3 and C4 GSLs derived from homoMet and dihomoMet amino acids (Table 1), which is consistent with the occurrence of GSLs derived from n-homoMet as well as from Phe and Trp in the Brassicaceae family [13]. Indirect analysis of GSLs via their degradation products was also performed. Myrosi-nase, both endogenous and exogenous, degraded GSLs enzymatically during the autolysis for 24 h, while thermal degradation was assessed using conventional (hydrodistillation, HD) and modern (microwave-assisted distillation, MAD; and microwave hydrodiffusion and gravity, MHG) techniques. The volatile isolates obtained from whole plant material were analyzed by GC-MS (Table 3). Sulfur-containing volatiles found in the analyzed samples differed depending on the method used for their isolation. Hydrodistillate and microwave distillate contained only one GSL degradation product, 3-(methylsulfonyl)propyl ITC, originating from **95**. On the other hand, three ITCs were identified in the dichloromethane extract with the highest percentage of allyl ITC (58.61%). Also, this was the only volatile isolate that contained 3-(methylsulfonyl)propyl ITC (iberin) derived from the main GSL **73** (28.2%), but with the lowest percentage of sulfanyl analogue (1.72%) among all isolates. Allyl ITC is an olefinic ITC derived from sinigrin (**107**) that was not detected by dGSL analysis (searched but not found), which is why it was concluded to be an artifact arising from the present methylsulfonyl ITC during GC-MS measurements (Figure 2). \begin{table}
\begin{tabular}{l l l l l l l} \hline \hline \multirow{2}{*}{**No. \({}^{*}\)**} & **Parent Glucosinolate** & **KI** & **HD** & **MAD** & **EXT** & **MHG** \\  & **Identified Breakdown Compound** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** \\ \hline
**95** & Glucoibervirin & & & & & \\  & 4-(Methylsulfonyl)butanenitrile \({}^{\text{b}}\) & 1083 & n.d. & n.d. & n.d. & 37.31 \\  & 3-(Methylsulfonyl)propyl isothi & \({}^{\text{a,b}}\) & 1308 & 99.90 & 99.11 & 1.72 & 60.05 \\  & Glucoiberin & & & & & \\  & Allyl isothi & \({}^{\text{a,b,c}}\) & 890 & tr & n.d. & 58.61 & n.d. \\  & 3-(Methylsulfonyl)propyl isothi & \({}^{\text{a,b}}\) & 1745 & n.d. & n.d. & 27.05 & n.d. \\ \hline  & Other volatiles & & & & & \\  & (Z)-Hex-2-enal \({}^{\text{b}}\) & 826 & n.d. & n.d. & 7.01 & n.d. \\  & \(S\)-methyl methanethiosulfinate \({}^{\text{b}}\) & 990 & tr & n.d. & tr & n.d. \\  & Nonanal \({}^{\text{b}}\) & 1105 & tr & tr & n.d. & n.d. \\  & Diethyl phtalate \({}^{\text{b}}\) & 1618 & n.d. & n.d. & 5.00 & 1.03 \\ \hline  & Total (\%) & & 99.90 & 99.11 & 99.39 & 98.39 \\  & Yield (\(\mu\)g/g) & & 243.03 & 137.23 & 40.36 & 51.49 \\ \hline  & & & & & & \\ \end{tabular} \({}^{*}\) No. –numbers are related to the glucosinolate number given in the review paper by [PERSON] et al. [15]. HD–hydrodistillate; MAD—microwave-assisted distillate; EXT—CH\({}_{2}\)Cl\({}_{2}\) extract after the 24 h autolysis with added myrosinase; MHG—extract obtained by microwave hydrodiffusion and gravity; KI—Kovats retention indices determined on a HP-SMS UI capillary column; n.d.—not detected, tr—traces. The percentages represent the average component precentes obtained from duplicate analyses on the HP-5 MS UI column. \({}^{\text{a}}\) Compound identified by mass spectra and KI comparison with a standard. \({}^{\text{b}}\) Compound identified by mass spectra comparison with the Wiley/NIST library. \({}^{\text{c}}\) This compound is the thermolysis product of 3-(methylsulfonyl)propyl ITC during GC-MS analysis (Figure 2).  
\end{table} 
Table 3: Volatiles obtained from the whole plant of _Iberis sempervirens_ using different methods of isolation. This was also observed in the case of GC-MS analyses of _Lunaria annua_ L. volatiles. Two alkenyl ITCs, pent-4-enyl ITC and hex-5-enyl ITC, were identified in the EXT and MHG, with no such alkenyl dGSLs identified by UHPLC-MS/MS analysis.