# Phytochemical Screening and Antioxidant Activity of Selected Estonian _Galium_ Species
## 2 Results and Discussion
### Analysis of Volatiles by SPME-GC-MS  
The volatiles of _Galium verum_ blossoms, herb, _Galium aparine_ herb, and _Galium mollogo_ herb were quantified and are shown in Table 4, which includes only the compounds that amount to more than 1.0% of total volatiles in each sample. Significant quantitative and qualitative differences were observed between the different _Galium_ species. There were three volatile compounds, hexanal, anethole, \(\beta\)-caryophyllene, that were identified in all analysed samples (out of all compounds that made up more than 1.0% of total volatiles in a specific sample). According to the previous studies, these are all compounds that should be present in _Galium_ species [43; 44; 45; 46]. It has previously been proven that anethole is effective against yeast, bacterial and fungal strains [52; 53], and caryophyllene-rich oil has been reported to have high inhibitory activity against some fungi and bacteria [54]. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Compound**} & \multirow{2}{*}{\begin{tabular}{c} **Rt,** \\ **min** \\ \end{tabular} } & \begin{tabular}{c} _Galium verum_ \\ **Blossoms,** \\ **\%** \\ \end{tabular} & \begin{tabular}{c} _Galium verum_ \\ **Herb,** \\ **\%** \\ \end{tabular} & \
\begin{tabular}{c} _Galium aparine_ \\ **Herb,** \\ **\%** \\ \end{tabular} &
\begin{tabular}{c} _Galium mollogo_ \\ **Herb,** \\ **\%** \\ \end{tabular} \\ \hline \(\beta\)-Methylbutanal & 3.72 & - & - & 1.7 & \textless{}1.0 \\
2-Methyl-4-hydroxy-cyclobutanone & 3.84 & - & - & 2.2 & - \\ \(\alpha\)-MethylpOrganoic acid & 5.37 & - & - & 2.0 & - \\ Hexanal & 6.44 & 1.2 & 1.9 & 2.4 & 1.1 \\ \(\beta\)-Methylbutyric acid & 7.43 & \textless{}1.0 & - & 7.5 & 2.8 \\ \(\alpha\)-Methylbutyric acid & 7.72 & \textless{}1.0 & \textless{}1.0 & 3.1 & - \\ (\(E\))-2-Hexenal & 7.85 & - & - & - & 2.7 \\
2,5,5-Trimethyl-1,3,6-heptatriene & 9.98 & 1.8 & \textless{}1.0 & - & - \\ \(\beta\)-Terpinene & 11.38 & - & 4.0 & - & - \\ Hexanoic acid & 11.41 & \textless{}1.0 & - & - & 3.4 \\ \(\beta\)-Prene & 11.49 & - & 7.7 & - & - \\
4-Terpineyn acetate & 12.22 & 1.3 & - & - & - \\ D-Limonene & 13.04 & - & 1.0 & - & - \\ Eucalyptus & 13.12 & 3.4 & 4.8 & - & - \\ Salicylaldehyde & 13.47 & 4.3 & \textless{}1.0 & 2.1 & 1.4 \\ Artemisia ketone & 13.96 & 15.2 & \textless{}1.0 & - & 1.6 \\ Artemisia alcohol & 14.66 & 4.5 & \textless{}1.0 & - & - \\
2-Methylene-hexanal & 14.83 & - & 1.2 & - & - \\ Linalool & 15.10 & - & 2.0 & - & - \\ Nonanal & 15.21 & 2.9 & \textless{}1.0 & 4.1 & 5.6 \\ \(\delta\)-Thujone & 15.67 & 7.2 & \textless{}1.0 & - & 1.2 \\ Camphor & 16.50 & 2.2 & 11.1 & - & - \\ \(p\)-Menthene & 16.75 & \textless{}1.0 & 7.0 & 4.4 & \textless{}1.0 \\ Artemisyl acetate & 17.17 & 13.5 & \textless{}1.0 & - & 2.4 \\ \(\alpha\)-Terpineol & 17.80 & - & 1.1 & - & - \\ Methyl salicylate & 17.94 & 1.0 & \textless{}1.0 & - & - \\ Estragole & 17.99 & - & 2.3 & - & - \\ Thymol methyl ether & 18.96 & 5.5 & \textless{}1.0 & 3.8 & 9.2 \\ Carvone & 19.29 & \textless{}1.0 & 4.4 & - & 1.1 \\ Anethole & 20.40 & 1.1 & 4.8 & 31.4 & 11.9 \\ Thymol & 20.49 & \textless{}1.0 & - & 8.4 & 6.1 \\ Isomethyl acetate & 20.59 & - & 1 & - & - \\
2,3,5,8-Tetramethyl-decane & 20.67 & - & 1.1 & - & - \\
2-Ethyl-4,5-dimethyl-phenol & 20.77 & - & - & \textless{}1.0 & 1.5 \\ Copaene & 22.84 & - & 2.9 & - & - \\ \(\beta\)-Bourbonene & 23.11 & \textless{}1.0 & \textless{}1.0 & \textless{}1.0 & 1.0 \\ Helminthogermacene & 23.25 & 1.3 & 1.2 & - & \textless{}1.0 \\ Borryl isobutyrate & 23.79 & 1.5 & - & - & - \\ \(\beta\)-Caryophyllene & 24.00 & 3.6 & 3.1 & 3.0 & 10.0 \\ Calarene & 24.30 & - & 1.4 & - & - \\ \(\alpha\)-Caryophyllene & 24.82 & \textless{}1.0 & 1.0 & \textless{}1.0 & - \\ \(\gamma\)-Muurolene & 25.32 & \textless{}1.0 & 1.0 & - & - \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Identified volatile compounds in the samples of the _Galium_ species. In general, the volatiles in _Galium verum_ blossom and herb samples were similar.