## 3 Results and Discussion  
### Preliminary Phytochemical Screening of Extracts  
The content of dried extract (d.e.) obtained after 48 h of maceration with 70% (v/v) aqueous ethanol ranged from 13.48-30.03% for bark and 19.71-29.13% for leaves of seven different _Salix_ species (Table 1). The highest extraction yield of bark was obtained for _S. triandra_, whereas _S. elegans_ and _S. purpurea_ had the greatest yield among the leaves.  
The amount of total phenolics in the analyzed species of the genus _Salix_ varied widely and ranged from 18.41-69.1 mg gallic acid equivalents (GAE)/g d.e. and 10.26-87.06 mg GAE/g d.e., for bark and leaves respectively (Table 1). The content of total flavonoids was in range from 2.88-31 mg quercetin equivalents (QE)/g d.e. for bark and 11.4-32.82 mg QE/g d.e. for leaves (Table 1). Generally, the amounts of phenolics were significantly higher in bark than in leaves extracts of different _Salix_ species, except for _S. triandra_. In addition, bark of the analyzed _Salix_ species contained larger amounts of phenolics than flavonoids. On the other hand, the amount of flavonoids was higher in leaves than in bark, except for _S. purpurea_ and _S. triandra_. In contrast to the total phenolics content in glycolic bark extract of _Salix alba_ (6.2 mg GAE/g) [26], the amounts of phenolics in ethanolic willow bark extracts from our study were 3-11 times higher, and in leaves extracts 1.75 to even 14 fold higher. This could be explained by differences in the polarity of solvents used for extraction, but genetic and environmental factors as well. Compared to another previously published study that reported very high concentrations of total phenolics in ethanolic bark extracts of _S. alba_ and _S. purpurea_, our results are 9.5 and 6 times lower in bark for these species, respectively [27]. Since the extractant and sample to solvent ratio was the same, differences could possibly be attributed to extraction length (2 days vs. 2 weeks). Comparing the obtained results with those reported earlier for _S. alba_ it can be noted that the analyzed extracts contain greater amounts of flavonoids [28]. Comparison of the obtained results with those previously published for other _Salix_ species indicate that beside salicin and its derivatives, flavonoids were one of the major fractions of phenolic compounds present in ethanolic bark extracts of _Salix_ species [27].  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Species**} & \multicolumn{2}{c}{**Vield [\%]1**} & \multicolumn{2}{c}{**Total Phenolics [mg GAE/g d.e.] 1**} & \multicolumn{2}{c}{**Total Flavonoids [mg QE/g d.e.] 1**} \\ \cline{2-7}  & **Bark** & **Leaf** & **Bark** & **Leaf** & **Bark** & **Leaf** \\ \hline _S. alba_ & 15.23 \(\pm\) 0.76 b  & 21.11 \(\pm\) 0.39 f  & 40.9 \(\pm\) 0.46 f  & 37.2 \(\pm\) 0.14 e  & 3.48 \(\pm\) 0.12 b  & 18.88 \(\pm\) 0.17 f  \\ _S.uplexica_ & 19.68 \(\pm\) 0.32 e  & 19.71 \(\pm\) 0.29 e  & 49 \(\pm\) 0.33 h  & 20.51 \(\pm\) 0.51 d  & 20.64 \(\pm\) 0.36 s  & 32.82 \(\pm\) 0.18 l  \\ _S. bulylonica_ & 17.41 \(\pm\) 0.19 c  & 19.82 \(\pm\) 0.38 e  & 20.17 \(\pm\) 0.42 d  & 10.88 \(\pm\) 0.18 a  & 3.13 \(\pm\) 0.37 d  & 11.4 \(\pm\) 0.52 d  \\ _S. elongas_ & 17.34 \(\pm\) 0.44 c  & 28.62 \(\pm\) 0.27 d  & 16.27 \(\pm\) 0.73 l  & 13.7 \(\pm\) 0.36 b  & 6.93 \(\pm\) 0.15 c  & 23.45 \(\pm\) 0.45 d  \\ _S. fragilis_ & 13.48 \(\pm\) 0.27 e  & 21.58 \(\pm\) 0.53 f  & 20.4 \(\pm\) 0.40 d  & 10.26 \(\pm\) 0.75 e  & 3.35 \(\pm\) 0.35 d  & 15.13 \(\pm\) 0.32 e  \\ _S. pur pururea_ & 18.45 \(\pm\) 0.68 d  & 29.13 \(\pm\) 0.88 h  & 69.1 \(\pm\) 0.25 l  & 42.83 \(\pm\) 0.17 g  & 31 \(\pm\) 0.54 k  & 28.38 \(\pm\) 0.22 l  \\ _S. triandra_ & 30.03 \(\pm\) 0.79 f  & 24.35 \(\pm\) 0.36 l  & 18.41 \(\pm\) 0.59 c  & 87.06 \(\pm\) 0.43 k  & 2.88 \(\pm\) 0.18 a  & 26.76 \(\pm\) 0.19 i  \\ \hline \hline \end{tabular}
\end{table}
Table 1: Yield of dried extract, total phenolics and total flavonoid content in bark and leaves extracts of the investigated _Salix_ species.