## 3 Results and Discussion
### Metabolites of Mertensia stylosa and M. serrulata: LC-MS Profile
#### 3.1.2. Phenolic Compounds  
Using HPLC-PDA-tQ-ESI-MS, twenty-six phenolic compounds were detected in both _Mertensia_ species (Figure 4, Table 3) and separated into hydroxycinnamates (22 compounds) and flavonoids (4 compounds) (Figure 5). The abundance of hydroxycinnamates was characteristic of the studied species of _Mertensia_. Derivatives of caffeic and quinic acids were authenticated by comparing the retention times and UV and MS spectral data with reference standards. Thus, derivatives of caffeic acid, including mono-caffeoylquinic (**5**, **9**, **12**), di-caffeoylquinic (**25**, **27**, **28**), caffeoylthreonic (**6**, **7**, **14**), caffeoylglyceric (**11**, **15**), caftaric (**22**), caffeoyltartronic (**20**), and rosmarinic (**30**) acids, were revealed. Derivatives of quinic acid, including feruloylquinic (**10**, **19**, **21**) and coumaroyulinic (**8**, **17**, **18**) acids, were also found. Components **13** and **16** produced a deprotonated ion with _m/z_ 311 and daughter ions with _m/z_ 179 and 161. The provisional structures of **13** and **16** were found to be _O_-caffeoyltartaric acid. Four flavonoid compounds were identified in the herbs of both _Mertensia_ species using the reference standards. The found flavonoids belonged to the flavonoid group depending on their aglycone structures and were derivatives of quercetin (**23**, **24**) and kaempferol (**26**, **29**). Quantification of the principal compounds of _M. stylosa_ and _M. serrulata_ herbs was achieved using HPLC-MS data, which allowed determination of 26 phenolic compounds. 5-O-Caffeoylquinic acid and quercetin-3-O-rutinoside were dominating compounds of the _M. stylosa_ herb while only quercetin-3-O-rutinoside dominated in the _M. serrulata_ herb. Additionally, a high content of rosmarinic acid was noted for the _M. stylosa_ herb. The total content of hydroxycinnamates in the _M. stylosa_ herb exceeded the content of flavonoids by 1.2 times, and the total content of phenolic compounds was 116.27 mg/g. Moreover, the total content of flavonoids in the _M. serrulata_ herb exceeded the total content of hydroxycinnamates by 2.54 times, and the total content of phenolic compounds was 41.90 mg/g. Earlier, rutin and rosmarinic acid were revealed in the seeds of _M. brevistyla_, _M. lancolata_, _M. arizonica_, _M. macdougalii_, _M. viridis_, _M. ciliata_, _M. alpinea_, _M. sibirica_, _M. virginica_, and _M. martima_ spp. _asiatica_[26]. Additionally, rosmarinic acid was found in the \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**No**} & \multirow{2}{*}{**tR, min**} & \multirow{2}{*}{**Compound 1**} & \multicolumn{3}{c}{**ESI-MS, _m/z_**} & \multicolumn{2}{c}{**Content, mg/g of Dry Plant**} \\  & & & & & **Weight \(\pm\) S.D.b** **} \\ \cline{3-6}  & & & **[M+H]\({}^{\ast}\)** & **MS/MS** & _M. stylosa_ & _M. serrulata_ \\ \hline
**1** & 7.11 & Lycopsamine 2 ** & 300 & 282, 256, 210, 156, 138, 120, 94 & 0.94 \(\pm\) 0.02 & 0.30 \(\pm\) 0.00 \\
**2** & 7.96 & Lycopsamine 3-oxide 2 ** & 316 & 298, 272, 254, 210, 172, 138, 120, 94 & 5.27 \(\pm\) 0.10 & 2.14 \(\pm\) 0.04 \\
**3*** & 9.65 & Isomer 3 ** & 342 & 324, 282, 256, 156, 138, 120, 94 & trace ** & trace  \\
**3** & 10.31 & Lycopsamine 7-O-acetate 4 ** & 342 & 300, 324, 282, 256, 156, 138, 120, 94 & 0.11 \(\pm\) 0.00 & 0.02 \(\pm\) 0.00 \\
**4*** & 10.90 & Isomer 4 ** & 358 & 340, 314, 298, 272, 254, 210, 172, 138, 120, 94 & trace  & trace  & trace  \\  & 11.53 & Lycopsamine \(N\)-oxide 2  & 358 & 340, 314, 298, 272, 254, 210, 172, 138, 120, 94 & 0.37 \(\pm\) 0.01 & trace  \\  & 7-O-acetate 5  & 6.69 & 2.46 \\ \hline \hline \end{tabular}  
* Compound identification was based on comparison of retention time and MS spectral data with reference standard (§) or interpretation of MS spectral data and comparison with literature data (§). b traces—LOQ (limit of quantification).  
\end{table} 
Table 2: Chromatographic (tR), mass-spectrometric data (ESI-MS), and content of pyrrolidine alkaloids in _Mertensia stylosa_ \(m\) _M. serrulata_ herb extracts.