## 3 Results and Discussion  
The steam extraction experiments gave a final water product (55-75 mL) and a small quantity of essential oil. This increased when leaves were used. The pH range of the hydrolates obtained was 4.5-5.2. For this reason the hydrolates could be applied to human skin (pH = 5). Hydrolates are lighter therapeutic agents than essential oils. They are mild, non-toxic and therefore ideal for use as a skin tonic or for therapeutic baths [25].  
The initial absorbance was measure from each experiment, to determine the extraction efficiency and thus to compare the extractions of ethanol and glycerine. The absorbance values are presented in Figures 2 and 3. The results showed that maceration with ethanol is slower that glycerine maceration. Recent research demonstrated the high capacity of glycerol as an extracting solvent, alone or combined eutectic solvents [26; 27; 28].  
\begin{table}
\begin{tabular}{c c c} \hline  & **Glycerol** & **Ethanol** \\ \hline NBP (\({}^{\circ}\)C) & 290 & 78.37 \\ Vapor pressure at 50 \({}^{\circ}\)C (mmHg) & \textless{}1 & 349 \\ Dielectric constant (25 \({}^{\circ}\)C) & 42.5 & 24.55 \\ Viscosity (cP) (30 \({}^{\circ}\)C) & 629 & 1.040 \\ \hline Density (g/mL) & 1.29 & 0.789 \\ \hline \end{tabular}
\end{table}
Table 2: Solvent properties.  
The yield was higher with ethanol than with glycerine--99% for ethanol and 90% for glycerine. The product obtained from ethanol maceration is a fluid liquid with a sweet and vegetal smell, soluble in water and alcohol. The product obtained from glycerine maceration is a viscous liquid with a sweet and vegetal smell, soluble in water and alcohol. The glycerine extract can be used as a dietary supplement because it contains appreciable amounts of anthocyanins and other nutrients [29].  
The total phenolic content of the flower extract was 59.3 \(\pm\) 2 mg gallic acid equivalent/g extract. The total flavonoid content of the extract was 16.2 \(\pm\) 0.2 mg quercetin equivalent/g extract. The alcohol extract of the flower has a good antioxidant activity similar to other extracts [30]. This antioxidant activity can be supported by previous literature, where the antioxidant effects of the flowers of _Sambucus nigra_ species have been demonstrated. [PERSON] et al. (2021) carried out aqueous extractions of elderflower, in which it was found to be a good source of natural antioxidants. Antimicrobial activity was also evaluated. The results were promising, showing the great potential of its bioactive compounds as nutraceuticalials, pharmaceuticals and cosmetics for therapeutic purposes [31]. Other studies, such as those by [PERSON] et al. (2020), highlighted the antioxidant activity of the fruits of this species due to their phenolic-compound content. Both studies found that the flavonoid with the greatest presence was quercetin, which would explain part of the high antioxidant activity of _Sambucus nigra_[20, 32].  
In conclusion, phenolic compounds have different disadvantages associated with them and it is necessary to develop strategies to improve their bioavailability, sustainable extraction technologies, and refinement and stability procedures to increase the range of applicability for industry [19].  
_Sambucus nigra_ species could be an important source of new compounds to be used in different industrial sectors, not only for the widely known pharmaceutical use but also  
Figure 3: Time variation of absorbance in glycerine maceration.  
Figure 2: Time variation of absorbance in ethanol maceration.  
for other sectors. The antimicrobial activity of various species is generally attributed to phenolic compounds present in the essential oils [33]. This makes it interesting to apply essential oils to the food industry as a preservative, thus avoiding the synthetic additives widely used today in many foodstuffs [34].