### Methods
#### 2.2.3 Characterization of the Extracts  
The vitamins (B1, B2, B5, B6, P, PP, C, A, and E) in the investigated extracts was determined by qualitative analysis based on the qualitative chemical reactions [25]. The quantitative content of vitamin C in plant extracts was determined using the iodometric method [26]. The method is based on the oxidation of the vitamin C molecule by iodate ions in an acidic environment. The quantitative content of flavonoids in extracts was determined using spectrophotometric method. We selected 4 mL of the test extract (solution A), which was placed in a 25 mL volumetric flask, into which we added 2 mL of a 2% ethyl alcohol solution of aluminum chloride and brought the volume to the mark with 95% ethyl alcohol. After 20 min, we measured the optical density on a spectrophotometer at a wavelength of 410 nm in a cell with a layer thickness of 10 mm. For comparison, we prepared solution B as described below. We inserted 4 mL of solution A in a 25 mL volumetric flask into which we added 1-2 drops of 1% hydrochloric acid. Then, the solution volume was brought to the mark by adding 95% ethyl alcohol. The content of flavonoids in terms of avicularin (expressed as percent XF in the dried raw material) was calculated as:  
\[\mathrm{X_{F}=(D\text{-}25\text{-}100)/(330\text{-}m),} \tag{1}\]  
where D is the optical density of the test extract; 25 is the total volume of the sample taken for determination; 330 is the specific absorption rate of avicularin complex with aluminum chloride at 410 nm; and m is the mass of the sample expressed in grams. The content of tannins was determined using titrimetric methods. An amount of 2 mL of the final extract was selected and placed in a conical flask with a capacity of 100 mL. Then, we added 60 mL of distilled water and 2 mL of indigosulfonic acid solution (1 g of indigo carmine was dissolved in 25 mL of concentrated sulfuric acid, then an additional 25 mL of concentrated sulfuric acid was added and diluted with water to 1000 mL by carefully pouring the resulting solution into water in a volumetric flask with a capacity of  
Figure 1: Technological scheme of vegetable raw material extraction silicone extractants. 1000 mL, and then stirring it). The obtained mixture was titrated with 0.1 mol/L potassium permanganate solution to a golden yellow color. Separately, we conducted a control experiment by titrating 2 mL of indigosulfonic acid in 60 mL of distilled water with 1 mL of 0.1 mol/L potassium permanganate solution. This corresponds to 4.157 mg of tannins according to Equation (2) and takes into account the conversion factor reported in the literature [27]. The content of tannins is determined in percent \(X_{\mathrm{T}}\) by the following formula:  
\[X_{\mathrm{T}}=((V_{1}-V_{2})\cdot K\cdot D\cdot V100)/m\cdot V_{3}, \tag{2}\]  
where \(V_{1}\) and \(V_{2}\) are the volumes (mL) of the potassium permanganate solutions for the titration of the sample and control, respectively. \(K\) is the correction factor for the titer (oxalic acid), while \(D\) is the conversion factor for the tannin (for hydrolyzed=0.004157, condensed tannins--0.00582). Finally, \(V\) is the total volume (mL) of the extract, m represents the mass of the raw material, and \(V_{3}\) is the volume (10 mL) of the extract obtained for the titration. The content of the extractives was determined using gravimetric method, as described below. For the test pipette, we selected 25 mL of the final test extract; transferred it to one that was previously dried at a temperature of 100-105 \({}^{\circ}\)C to constant weight; accurately weighed a porcelain cup with a diameter of 7-9 cm; and evaporated it in a water bath until it reached dryness. The cup with the residue was dried at a temperature of 100-105 \({}^{\circ}\)C to constant weight, then cooled for 30 min in a desicactor, at the bottom of which was anhydrous calcium chloride, and weighed.