## 2 Materials and Methods
### Total Phenolic and Flavonoid Content and Antioxidant Capacity Measurements  
The total content of phenolic compounds was determined according to the [PERSON] and [PERSON] (1965) [24] original method modified to enable the measurement using a microplate reader. Briefly, 20 uL of diluted tinctures were pipetted into the microplate wells then, 100 uL of 10\(\times\) diluted Folin-Ciocalteu reagent was added to the wells and finally, 80 uL of 7.5% Na\({}_{2}\)CO\({}_{3}\) solution was added. The plate was put aside in a dark place for 1 h. After this time, the absorbance was measured using a microplate reader (EPOCH2, Biotek, Winooski, VT, USA) (\(\lambda\) = 760 nm) against the blank (sample replaced with an equal volume of distilled water). Results were expressed as gallic acid equivalents (GAE) from the prepared standard curve in the range of 0-150 ug/mL (y = 0.3364x, r\({}^{2}\) = 0.9914). The total content of flavonoids was determined according to the [PERSON] (2013) [25] method with the modification enabling the measurement using a microplate reader. One hundred \begin{table}
\begin{tabular}{c c c} \hline \hline  & **Sample** & **Description** \\ \hline
1 & Control tincture & 100 g walnuts + 100 mL 40\% ethanol (control; kept in light) \\
2 & Control tincture kept in dark & 100 g walnuts + 100 mL 40\% ethanol (control; kept in dark) \\
3 & Tincture with ginger & 100 g walnuts + 2 g fresh, grated ginger + 100 mL 40\% ethanol (kept in light) \\
4 & Tincture with cloves & 100 g walnuts + 2 g crushed cloves + 100 mL 40\% ethanol (kept in light) \\
5 & Tincture with bay leaves & 100 g walnuts + 2 g shredded bay leaves + 100 mL 40\% ethanol (kept in light) \\
6 & Tincture with juniper fruit & 100 g walnuts + 2 g crushed juniper fruit + 100 mL 40\% ethanol (kept in light) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The composition of the prepared tinctures. Figure 1: The scheme of the experiment. microliters of diluted tinctures were poured into the wells, then 100 \(\mu\)L of 2% methanolic AlCl\({}_{3}\) solution was added. The plate was placed aside in a dark place for 10 min. After this time, the absorbance was measured using a microplate reader (\(\lambda\) = 415 nm) against the blank (sample replaced with an equal volume of distilled water). Results were expressed in mg as quercetin equivalents (QE) using the prepared standard curve in the range of 0-120 \(\mu\)g/mL (y = 0.0655x, r\({}^{2}\) = 0.9999). The antioxidant activity was measured using FRAP, DPPH, and ABTS methods. Samples measured with the FRAP method were assayed according to [PERSON] (1996) [26] with the modification enabling measurement using a microplate reader. Twenty microliters of diluted samples were poured into the wells, 180 \(\mu\)L of FRAP reagent (5 mL of 10 mM 2,4,6-Tris(2-pyridyl)-s-triazine (TPTZ) in 40 mM of hydrochloric acid, 5 mL of 20 mM ferric chloride and 50 mL of acetate buffer (0.3 M; pH = 3.6) was added. Then the plate was incubated for 10 min at 37 \({}^{\circ}\)C. The absorbance was measured (\(\lambda\) = 593 nm) against the blank (sample replaced with an equal volume of distilled water). Results are expressed in \(\mu\)g of Trolox equivalents (TE) based on the prepared standard curve in the range of 0-300 \(\mu\)mol/mL (y = 0.1522x, r\({}^{2}\) = 0.9989). The DPPH method was assayed according to [PERSON] (1958) [27] with the modification enabling the measurement using a microplate reader. Twenty microliters of diluted tinctures were poured into the wells then, 180 \(\mu\)L of DPPH reagent diluted with methanol to the absorbance level of ca. 0.9 was added. The plate was placed in a dark place for 30 min. Absorbance was measured at 517 nm against the blank sample (pure methanol) using a Biottek EPOCH2 microplate reader.