# Sea Buckthorn Leaves as a Potential Source of Antioxidant Substances
## 3 Results and Discussion
In the case of delphinidin as well as cyanidin, variation was observed in the content of these compounds in SBT by the experimental factors studied. The raw material obtained in the 2016 growing season was characterised by a significantly higher content of these compounds, and, among the cultivars, Hergo and Leikora were characterised by a higher content of delphinidin. The presence of pelargonidin, which is common in plant raw materials, was not found in the tested raw material. Previous studies have confirmed the presence of a few alkaloids in the biomass of sea buckthorn, e.g., hyppophamide (seeds), cauilexin (peels of fruits), or harman (leaves and branches) [57; 73]. This study confirmed the presence of benzophenanthridine alkaloidchelerythrine. This compound shows properties that make it likely that it will be a component of many new drugs, especially anticancer drugs [74]. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Factor**} & **Total Flavonoids** & **Flavonols mg** & **Anthocyanins** & **Proanthocyanindins** & **Total Tannins mg** \\  & **(mg QEE\({}^{2}\)/1 g DM \({}^{3}\)** & **QEE\({}^{1}\) g DM** & **mg/g DM** & **mg/g DM** & **TA\({}^{4}\)/1 g DM** \\ \hline \multicolumn{6}{c}{Year} \\ \(p\)\({}^{5}\) & =0.931 & =0.868 & =0.004 & =0.015 & =0.029 \\
2014 & 281.05 a \({}^{6}\) & 79.29 a & 10.928 b & 8.634 a & 1.429 a \\
2015 & 281.66 a & 80.71 a & 6.932 a & 7.860 a & 1.445 ab \\
2016 & 282.58 a & 80.70 a & 6.375 a & 18.517 b & 1.516 b \\ \hline \multicolumn{6}{c}{Cultivar} \\ \(p\) & =0.833 & =0.892 & =0.430 & =0.570 & =0.128 \\ Ascola & 283.54 a & 80.53 a & 9.202 a & 11.136 a & 1.491 a \\ Habego & 282.72 a & 81.37 a & 7.710 a & 14.547 a & 1.413 a \\ Hergo & 279.51 a & 79.18 a & 7.794 a & 10.426 a & 1.471 a \\ Leikora & 281.28 a & 79.56 a & 7.608 a & 10.573 a & 1.479 a \\ \hline \multicolumn{6}{c}{\({}^{1}\)SBT—sea buckthorn; \({}^{2}\)QE—quercetin equivalent; \({}^{3}\)DM—dry matter; \({}^{4}\)TA—tanic acid; \({}^{5}\)_p_—probability of null hypothesis rejection (H0; m = m2.... = m2); \({}^{6}\) means with at least one same letter (a, b) do not differ statistically at \(p\) = 0.05 (for all columns, separately).} \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Total and individual flavonoids in SBT \({}^{1}\) leaves. The content of cheylethrine in SBT leaves was determined by the climatic conditions of the growing season. By far, the highest content of the alkaloid was found in the 2016 raw material. The cheylethrine content in the raw material of the tested cultivars was close to statistical variation. The Ascola cv. showed a clear tendency to accumulate less of this valuable alkaloid. Extracts from medicinal plants with cheylethrine are components of veterinary and human phytopreparations. They display distinct antibacterial and anti-inflammatory properties. [PERSON] et al. (2017) showed that an average daily oral dose of alkaloids up to 5 mg per 1 kg of animal body weight is safe for piglets. [PERSON] et al. (2016) conducted a detailed evaluation of the pharmacokinetic characteristics of a mixture of sanguinarine and CHE in broiler chickens following p.o. and showed that this addition to feed is safe because of the first-pass effect after intestinal and liver metabolism. The state of knowledge on the biological activity of flavonoid compounds clearly indicates that their positive effects on the body are mainly due to their antioxidant properties. This is possible due to the presence of hydroxyl groups in their structure. It has been shown that the more hydroxyl groups in the molecule, the stronger the antioxidant effect ([PERSON], 1977; [PERSON], 1978). Of the labelled compounds, rutoside has the most -OH groups--10, delphinidin has 6, quercetin and cyanidin have 5, and peonidin has the least--4. The abundance of phenolic compounds in SBT leaves confirmed previous studies by other authors, including [PERSON] et al. (2019). The PCA analysis confirmed the significant variation in leaf quality of the studied SBT cultivars harvested in different growing seasons (Figure 3).