## 2 Results and Discussion
Protocatechic acid is reported to possess an assortment of biological activities, i.e., antibacterial, antiviral, anticancer, antiosteoporotic, and antioxidant, among others [34]. The overall distribution of the different classes of metabolites is presented in Figure 1. \begin{table}
\begin{tabular}{l c c c c} \hline \hline
**RI** & **Class/Name** & **Modesto** & **Stanley** & **Stendesto** \\ \hline \multicolumn{5}{c}{**Sugar acids and alcohols**} \\
1920 & Sorbitol & 7.22 \(\pm\) 2.32 a & 12.31 \(\pm\) 3.95 a & 11.53 \(\pm\) 3.70 a \\
2009 & Gluconic acid & 0.12 \(\pm\) 0.04 b & 0.30 \(\pm\) 0.10 a & 0.11 \(\pm\) 0.03 b \\
2018 & Glucaric acid & 0.25 \(\pm\) 0.08 a & 0.15 \(\pm\) 0.05 a & 0.12 \(\pm\) 0.04 a \\
2041 & Myo-Inositol isomer & 0.83 \(\pm\) 0.27 a & 0.53 \(\pm\) 0.17 ab & 0.29 \(\pm\) 0.09 b \\
2101 & Myo-Inositol isomer & 2.05 \(\pm\) 0.66 a & 0.21 \(\pm\) 0.07 b & 0.74 \(\pm\) 0.24 b \\ \hline \multicolumn{5}{c}{**Mono- and disaccharides**} \\
1855 & Fructose isomer & 2.38 \(\pm\) 0.76 b & 6.48 \(\pm\) 2.08 ab & 7.05 \(\pm\) 2.11 a \\
1869 & Fructose isomer & 1.60 \(\pm\) 0.51 b & 4.95 \(\pm\) 1.59 ab & 5.51 \(\pm\) 1.77 a \\
1876 & 1-Methyl-a-D-glucopyranoside & 0.10 \(\pm\) 0.03 b & 0.27 \(\pm\) 0.09 ab & 0.36 \(\pm\) 0.12 a \\
1882 & Glucose isomer & 2.78 \(\pm\) 0.89 b & 9.90 \(\pm\) 2.18 a & 12.00 \(\pm\) 2.85 a \\
1898 & Glucose isomer & 0.83 \(\pm\) 0.27 b & 2.21 \(\pm\) 0.71 ab & 2.60 \(\pm\) 0.83 a \\
1937 & Glucose 1-phosphate & 0.16 \(\pm\) 0.05 b & 0.25 \(\pm\) 0.08 b & 4.05 \(\pm\) 1.30 a \\
2687 & Sucrose & 15.54 \(\pm\) 2.99 a & 7.39 \(\pm\) 1.37 b & 10.25 \(\pm\) 2.29 ab \\ \hline \multicolumn{5}{c}{**Phenolic acids**} \\
1835 & Protocatechic acid & 0.32 \(\pm\) 0.10 ab & 0.17 \(\pm\) 0.06 b & 0.60 \(\pm\) 0.19 a \\
1940 & _trans-p_-Coumaric acid & 0.55 \(\pm\) 0.18 a & 0.41 \(\pm\) 0.13 a & 0.24 \(\pm\) 0.10 a \\
2106 & _trans_-Ferulic acid & 0.19 \(\pm\) 0.07 a & 0.38 \(\pm\) 0.12 a & 0.26 \(\pm\) 0.08 a \\ \hline \multicolumn{5}{c}{**Others**} \\
1400 & Tetradecane & 0.64 \(\pm\) 0.21 a & 0.46 \(\pm\) 0.15 ab & 0.13 \(\pm\) 0.04 b \\
1600 & Hexadecane & 0.29 \(\pm\) 0.09 a & 0.20 \(\pm\) 0.06 a & 0.12 \(\pm\) 0.04 a \\ \hline \hline \end{tabular} Amino acids marked in blue color are essential; RI—retention index. Different letters in the same row indicate statistically significant differences (p \(<\) 0.05) according to ANOVA and the Tukey test.  
\end{table} 
Table 1: _Cont._The plum-apricot hybrid kernels had more mono- and disaccharides and phenolic acids compared to the parents, the same amount of amino acids as apricot kernels, and decreased sugar acids and alcohols. Considering the amount of fatty and organic acids, the amount was more similar to the apricot kernels than to the plum kernels. The distribution of the individual compounds was different, and their amounts contributed differently not only to the specific chemical family but also to the kernel variety. Due to the lack of relevant data, comparison with subject reference to other papers cannot be conducted. The fatty acids content is presented in Table 2, where a total of twelve compounds were identified, including four fatty alcohols. Although more saturated fatty acids were discovered, their amount did not exceed the value of unsaturated fatty acids. The polyunsaturated fatty acids were more frequent, but the amount of monounsaturated fatty acids was greater. The saturated/unsaturated ratios in the studied kernels are as follows: 0.93 (\"Modesto\"), 1.01 (\"Stanley\"), and 0.96 (\"Stendesto\"). Myristic, linoleic, and oleic acids were the predominant ones. Linoleic and oleic acids have been reported as promising anti-mycobacterial agents with high antioxidant