## 3 Results and Discussion
### Antioxidant Activity  
Literature data and the results of the studies reported in this publication indicate that the chemical composition of extracts varies considerably depending on the extractant used, suggesting potential differences in the efficacy and use of each extract. The forms and stability of the compounds in the extracts from _H. perforatum_ determine their biological activity. It appears challenging to obtain the complete chemical composition of this plant using a single extraction method and a single solvent. The choice of extraction method, in addition to extraction conditions such as temperature, solvent concentration, and duration, depends significantly on the compounds present in the plant and their properties (polarity and solubility). All of these factors may impact the bioactive properties of the obtained extract [64]. The available research results refer to extracts prepared using, among others,methanol or water, while no data are available on glycerol extracts, glycol extracts, or their mixtures with water. A study by [PERSON] et al. [65] showed that scavenging activity depended on the type of extractant, as well as the extraction time, ranging from 53.89% to 91.98%. The highest results were obtained for samples prepared in undiluted methanol and extracted for 60 min, whereas the antioxidant capacity of the aqueous extracts was low. The results presented in Table 5 indicate that the GL-WE of _H. perforatum_ demonstrated stronger antioxidant properties than the PEG-WE due to higher DPPH scavenging activity and FRAP value.  
The well-known antioxidant activity of _H. perforatum_ extracts is related to the high content of phenolic compounds. However, there is still insufficient evidence to determine which class of phenols is most responsible for these antioxidant properties. In addition, the structures of antioxidants and the interactions between them play an important role in determining antioxidant activity [64]. It has been demonstrated that the free radical-scavenging activity is predominantly attributed to flavonoid glycosides and phenolic acids (such as chlorogenic acid), while phloroglucnols (which lack the polyphenic structure), biflavonoids (which lack the catechol moiety), and naphthodianthrones exhibit no significant activity [66]. Flavonoid glycosides (mainly quercetin-3-\(O\)-rutinoside) and phenolic acids, in combination with a sugar unit (mainly galactoside and rhamnoide), appear to contribute significantly to the neutralization of free radicals, i.e., showing high antioxidant activity [67]. As demonstrated by [PERSON] et al. [68], the antioxidant potential of _H. perforatum_ ethanolic extracts is directly correlated with the presence of phenolic compounds, with quercetin and its glycosidic derivatives being primarily responsible for this property. These compounds play an important role in both radical scavenging and inhibiting lipid peroxidation activity. A study by [PERSON] et al. [69] showed that the antioxidant activity of extracts is strongly correlated with their composition; the most active fractions are those rich in flavonoid glycosides (followed by very small amounts of phenolic acids) and poor in biflavonoids (amentoflavone and biapigenin). In our study, the higher antioxidant activity of GL-WE compared to PEG-WE was also associated with a higher concentration of quercetin glycosides: isoquercitrin, rutin, and hyperoside. The rutin contained in GL-WE, as indicated by the literature data, has antioxidant and antiaging potential by inhibiting the mitochondrial aging process and increasing GSH content and SOD activity [70].