## 3 Results and Discussion
### Identification of Metabolites by LC/Q-TOF/HRMS Analysis
\begin{tabular}{c} 315.0492; \\ 308.1104 \\ \end{tabular}  & 7.20 & 623.1611 & \(-\)1.12 & \begin{tabular}{c} 315.0492; \\ 271.0245; \\ 243.0292; \\ 151.0401 \\ \end{tabular}  & 7.20 \\ \hline
12 & 260 & \begin{tabular}{c} Isohammetin \\ hexoside \\ \end{tabular}  & C\({}_{22}\)H\({}_{20}\)O\({}_{12}\) & & n.d. & \ \begin{tabular}{c} 447.1017 \\ 191.0334 \\ \end{tabular}  & \(-\)4.69 & \begin{tabular}{c} 315.0520; \\ 151.0045 \\ \end{tabular}  & 7.27 \\ \hline
13 & 213 & Cincinnati & L/D** & C\({}_{24}\)H\({}_{20}\)O\({}_{6}\) & 453.1175 & \(-\)1.10 & \ \begin{tabular}{c} 343.0794; \\ 191.0334 \\ \end{tabular}  & 7.54 & 451.1028 & \(-\)1.55 & \begin{tabular}{c} 341.08656; \\ 189.0190 \\ \end{tabular}  & 7.51 \\ \hline
14 & 220 & Resveratrol & C\({}_{41}\)H\({}_{20}\)O\({}_{3}\) & 229.0859 & 0.00 & \begin{tabular}{c} 135.0428; \\ 177.0497; \\ \end{tabular}  & 7.70 & n.d. & n.d. \\ \hline
15* & 218 & Luteolin & C\({}_{53}\)H\({}_{40}\)O\({}_{6}\) & n.d. & \ \begin{tabular}{c} 285.0392 \\ 25.0392 \\ \end{tabular}  & \(-\)4.56 & \begin{tabular}{c} 267.0258; \\ 151.9210 \\ \end{tabular}  & 9.14 \\ \hline
16 & - & Parillin & C\({}_{51}\)H\({}_{48}\)O\({}_{2}\) & 1049.5525 & \(-\)0.19 & \begin{tabular}{c} 273.2220; \\ 255.2120 \\ \end{tabular}  & 9.55 & n.d. & n.d. \\ \hline
17 & 277 & Naringenin & C\({}_{51}\)H\({}_{20}\)O\({}_{5}\) & n.d. & \ \begin{tabular}{c} 271.0622 \\ 17.0622 \\ \end{tabular}  & 3.69 &
\begin{tabular}{c} 151.0031; \\S. aspera_ as an important source of bioactive compounds, namely phenolic compounds and steroidal saponins. Regarding both positive and negative ionization modes, flavonoid glycosides and aglycons were identified as major metabolites of _S. aspera_ aerial parts, and rutin was the major compound detected. Compounds isoshaftoside, isorhamentin pentoside-hexoside, luteolin glucoside and isorhamentin hexoside have not been previously reported in the genus _Smilax_. In addition, types of steroidal saponins belonging to the furostane, spirostane and isospirostane classes were detected. Spirostane and isospirostane saponins are six-ring stereoisomers and differ at the \(R\) or \(S\) configuration of the methyl group at the position C-27 of the F ring. The sugar moiety is directly attached to the steroid nucleus, contrary to the five-ring furostane saponin that is adhered to the position C-26, separated from the saponin aglycon skeleton by a hemiacetal hydroxyl group. The position C-3 of the steroidal saponins is occupied by a group of sugar moieties most common of which are glucopyranosyl, rhamnopyranosyl, galactopyranosyl, fructopyranosyl and arabinopyranosyl residues [16]. Position C-26 is of crucial importance for the identification of the type of saponin presented. When this position is occupied by a sugar moiety, as in the case of furostane saponins, then the cleavage of the E-ring from which the characteristic neutral loss of 144 D arises, occurs after the elimination of the attached sugar moiety. In our study, the detected saponins presented a main peak at _m/z_ 253 (when a double bond at position C-C6 was presented) or at _m/z_ 255, arising from the main aglycon skeleton. The chemical profile of various Smilax species has been elucidated and many pharmacological properties are related to the presence of steroidal saponins and flavonoids [20; 21; 22]. Regarding _S. aspera_, the presence of steroidal saponins in the underground plant organs which is also the most well-studied part of the plant and the presence of carotenoids at the berries, has been reported [16; 23; 24]. Nevertheless, uncertainty still exists about the phytochemical profile and the antioxidant activity of leaves and stems. Natural antioxidants are considered more effective and less harmful than synthetic ones; therefore, the search for new natural antioxidant sources has been intensified [25; 26]. The especially rich Mediterranean flora offer remarkable research opportunities for the discovery of new natural antioxidants.