## 3 Results and Discussion  
### Polyphenol Content and Antioxidant Capacity  
The total content of polyphenols and flavonoids was determined in all tinctures. The antioxidant capacity was also measured using the FRAP, DPPH, and ABTS methods. The results are summarized in Table 2.  
In the basic control tincture (1) the total phenolic content was at the level of 3.56 mg GAE per mL. Maceration in the darkness resulted in a significant increase of phenolic content, as well as of the antioxidant capacity. The highest polyphenol content was determined in tinctures 2 and 5, prepared in darkness and enriched with bay leaves. Keeping the tincture in the dark may have a beneficial effect on the content of bioactive ingredients that can be degraded when exposed to light. The additives used enhanced the antioxidant activity of tinctures.  
The results obtained are comparable with the data available in the literature on traditional green walnut liquefurs (Nocino), which contained from 1.18-3.52 mg of catechin equivalents per mL [13,14]. In commercial tinctures, the variability was greater, from 0.23-3.88 mg of catechin equivalents per mL [13]. According to this data, tannins accounted for most of the polyphenols. Antiradical activity determined by the DPPH method according to the literature was from 0.019-2.38 umol TE/mL for commercial samples and up to 8.94 umol TE mL\({}^{-1}\) for liquefurs prepared with the infusion method [13,14]. The ABTS method was used to investigate the antioxidant potential of tinctures made from harvests at various stages of maturity (at the beginning and end of July), as well as from green husks and leaves of _J. regia_. The tinctures of walnuts harvested on 25 July and green husks were the most active [32]. The correlation between the content of total phenolic compounds and flavonoids and the antioxidant capacity measured with three methods was also investigated (Table 3). All calculated Pearson's correlation coefficients were significant at the level of \(p\) = 0.05, indicating that the share of polyphenols, including flavonoids, was key in shaping the antioxidant activity of the tinctures.  
\begin{table}
\begin{tabular}{c c c c c c} \hline
**Tincture** & **TPC** & **TFC** & **FRAP** & **DPPH** & **ABTS** \\
**[mg GAE mL\({}^{-1}\)]** & **[mg QE mL\({}^{-1}\)]** & **[umol TE mL\({}^{-1}\)]** & **[umol TE mL\({}^{-1}\)]** & **[umol TE mL\({}^{-1}\)]** \\ \hline \(1\) & 3.56 \(\pm\) 0.03 a & 1.80 \(\pm\) 0.06 a & 21.77 \(\pm\) 0.15 a & 11.37 \(\pm\) 0.51 a & 40.58 \(\pm\) 1.82 a,b \\ \hline \(2\) & 4.30 \(\pm\) 0.05 c & 2.18 \(\pm\) 0.01 c & 26.64 \(\pm\) 0.44 d & 13.69 \(\pm\) 0.33 b & 46.91 \(\pm\) 0.50 c \\ \hline \(3\) & 4.05 \(\pm\) 0.05 b & 1.99 \(\pm\) 0.03 b & 25.31 \(\pm\) 1.02 d,c & 12.23 \(\pm\) 0.22 a,b & 43.30 \(\pm\) 0.79 b \\ \hline \(4\) & 3.88 \(\pm\) 0.05 a & 2.40 \(\pm\) 0.06 d & 24.41 \(\pm\) 0.60 c & 11.59 \(\pm\) 1.37 a,b & 48.27 \(\pm\) 0.32 c,d \\ \hline \(5\) & 4.29 \(\pm\) 0.04 c & 1.93 \(\pm\) 0.09 a,b & 25.21 \(\pm\) 0.43 c,d & 13.15 \(\pm\) 0.85 a,b & 44.78 \(\pm\) 0.10 b,c \\ \hline \(6\) & 3.95 \(\pm\) 0.03 b & 1.87 \(\pm\) 0.04 a,b & 23.78 \(\pm\) 0.34 b & 12.09 \(\pm\) 0.80 a,b & 41.23 \(\pm\) 0.78 a,b \\ \hline \end{tabular} Values are the means \(\pm\) standard deviation (n = 3), means marked with the same letter are not statistically different (\(p\) > 0.05). GAE—gallic acid equivalents, QE—quercetin equivalents, TE—Trolox equivalents. 1-6—tinctures samples (see Table 1).  
\end{table}
Table 2: Polyphenolic and flavonoids contents as well as antioxidant properties of green walnut tinctures.