# Evaluation of _Sambucus nigra_ L. Biopotential as an Unused Natural Resource
## 3 Results and Discussion
### Total Bioactive Compounds and Phenolic Components
#### 3.1.2 Phenolic Profile

Table 1: Concentration \({}^{\ast}\) of detected ** phenolic acids in elderberry extracts (\(\upmu\)g/mg extract). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Extraction Technique** & **UAE** & **MAE** & **MAC** & **UAE** & **MAE** & **MAC** \\ \hline
**Solvent** & \multicolumn{3}{c}{**H\({}_{2}\)O**} & \multicolumn{3}{c}{**50\% EtOH**} \\ \hline
**Flavonoids** & & & **ug/mg** & & \\ \hline Narringenin & 0.003 \(\pm\) 0.001 \({}^{\rm d}\) & 0.006 \(\pm\) 0.000 \({}^{\rm c}\) & 0.003 \(\pm\) 0.000 \({}^{\rm d}\) & 0.007 \(\pm\) 0.001 \({}^{\rm b}\) & 0.007 \(\pm\) 0.001 \({}^{\rm c}\) & 0.010 \(\pm\) 0.001 \({}^{\rm a}\) \\ Epicatechinrespectively) obtained by MAC. The lower content of \(p\)-OH benzoic acid was observed in the extracts obtained by modern extraction techniques. Due to the non-polar characteristics of the terpene structure, the presence of unsolic acid was expected in ethanol extracts. MAE extract was the richest source of unsolic acid (6.623 \(\mathrm{\SIUnitSymbolMicro\text{g}}\)/mg), followed by MAC (4.978 \(\mathrm{\SIUnitSymbolMicro\text{g}}\)/mg), while the lowest unsolic acid content was recorded in UAE extract (2.486 \(\mathrm{\SIUnitSymbolMicro\text{g}}\)/mg). The presence of unsolic acid in fresh elderberry fruit extracts in high concentrations is of great importance for biological potential. Namely, unsolic acid is a potent natural agent that has the ability to prevent the proliferation of tumor cells, protect mental health and also has anti-oxidative, anti-inflammatory, and antimicrobial activity. Due to its high content, use of fresh elderberry fruits extracts as a potential antitumor agent can be implicated [31]. In terms of flavonoids, elderberry extracts are characterized by the dominant presence of ruin, quercetin, and quercetin-3-O-hexoside. Rutin was more prevalent in ethanol than in water extracts, and its highest concentration was identified in the extracts obtained by MAC, MAE, and UAE extraction (8.807, 8.086, and 7.388 \(\mathrm{\SIUnitSymbolMicro\text{g}}\)/mg, respectively). The presence of ruin in UAE and MAE water extracts did not differ significantly (7.260 and 6.302 \(\mathrm{\SIUnitSymbolMicro\text{g}}\)/mg, respectively). The higher concentration of ruin in ethanol extracts is caused by its poor solubility in water solutions; therefore, the selection of a suitable extraction technique will largely contribute to the more efficient isolation of the ruin from the plant material. A large number of food products that are present in the US market contain ruin in their composition, which is of utmost importance for the promotion of health and the enrichment of products with natural products [32]. Another very potent, biologically active compound, quercetin, was, next to ruin, the most prevalent flavonoid in fresh elderberry fruit extracts. The content of quercetin in the analyzed extracts follows the trend of ruin content, thus quercetin was mostly present in ethanol, while lower concentrations were detected in water elderberry extracts. The highest presence of quercetin was detected in MAC extract (0.466 \(\mathrm{\SIUnitSymbolMicro\text{g}}\)/mg), while extracts obtained by modern extraction techniques were a weaker source of quercetin. Regarding water extracts, MAE extract was a better source of quercetin than MAC and UAE extracts. An important carrier of the biological potential of elderberry extracts was quercetin-3-O-hexoside, which was most prevalent in ethanol MAC and MAE extracts (0.372 and 0.340 \(\mathrm{\SIUnitSymbolMicro\text{g}}\)/mg, respectively). The use of two different solvents for isolation of quercetin-3-O-hexoside in the case of UAE ethanol and water extracts did not cause significantly different results. Quinic acid is a plant product, a precursor in the synthesis of phenolic compounds, stored mainly in the bark of the plants. In this study, quinic acid was identified in significant concentration, which indicates the presence of different phenolic compounds, even those not included in this analysis.