## 2 Materials and Methods
### Phytochemical Research  
The flavonoids were rigorously analyzed using HPLC on a chromatograph Agilent Technologies 1200. The mobile phase was precisely composed of acetonitrile (A) and a 0.1% formic acid solution in water (B). A systematic gradient elution was employed under the following conditions: at 0 min, A was set at 30% and B at 70%; by 20 min, A was increased to 70% while B decreased to 30%; at 22 min, A reached 100% and B dropped to 0%; and at 30 min, A remained at 100% and B at 0%. Separation was effectively achieved on a Zorbax SB-C18 chromatographic column (3.5 um, 150 \(\times\) 4.6 mm) from Agilent Technologies (Santa Clara, CA, USA), maintaining a flow rate of 0.25 ml/min. A sample injection volume of 100 \(\upmu\)L was utilized, and the column was consistently maintained at 25 \({}^{\circ}\)C. Detection was conducted using a diode-array detector, recording signals at 280 and 365 nm, with spectra comprehensively captured in the range of 210-270 nm [27; 28].  
The assay of hydroxycinnamic acids was carried out using the chromatograph Agilent Technologies 1200. The mobile phase served methanol (A) and 0.1% formic acid in water (B). The gradient elution parameters were precisely set at 0 min--A (25%): B (75%); at 25 min--A (75%): B (25%); at 27 min--A (100%): B (0%); and at 35 min--A (100%): B (0%). Separation was effectively achieved on a Zorbax SB-Aq column (4.6 mm \(\times\) 150 mm, 3.5 um) (Agilent Technologies, USA) with a flow rate of 0.5 ml/min, a column temperature maintained at 30\({}^{\circ}\)C, and an injection volume of 4 \(\upmu\)L. Detection was conducted with a diode-array detector, with signals meticulously monitored at 250 and 275 nm, and absorption spectra consistently recorded within the range of 210-270 nm [29; 30; 31].  
The analysis of tannin metabolites was conducted using the chromatograph Agilent Technologies 1200. The mobile phase effectively comprised methanol (A) and 0.1% formic acid in water (B). The gradient elution conditions were defined as follows: at 0 min--A (20%): B (80%); at 25 min--A (75%): B (25%); at 27 min--A (100%): B (0%); and at 35 min--A (100%): B (0%). The separation process employed a Zorbax SB-C18 chromatographic column (3.5 um, 150 \(\times\) 4.6 mm) from Agilent Technologies, USA, operating with a flow rate of 0.25 mL/min, a thermostat set to a precise 35 \({}^{\circ}\)C, and an injection volume of 4 \(\upmu\)L. Thediode-array detector reliably recorded signals at 250 and 275 nm, while absorption spectra were systematically captured across the range of 210-270 nm [32; 33].  
The substance identification and quantification were based on comparisons with standard reference materials from Sigma-Aldrich (Burlington, MA, USA). The quantitative analysis of the total flavonoid content, expressed as rutin, was carried out spectrophotometrically according to the _Ukrainian State Pharmacopoeia_ (SPHU) 2.0 [28; 34]. The quantitative determination of tannins and total amounts of polyphenols in terms of pyrogallol was carried out using the spectrophotometric method in accordance with the pharmacopeial method SPHU 2.0 [34; 35; 36]. The quantitative content of polysaccharides was determined according to the methodology described in the monograph \"Plantago major leaves\" in the SPHU 2.0, Vol. 3 [35].