## 3 Results and Discussion  
### Total Phenolic Content  
The first inquiry of the study focuses on the impact of the extraction temperature on the total phenolic content of the studied herbal aqueous extracts. Total phenolic content of chamomile and sage aqueous extracts affected by extraction temperature are presented in Table 1.  
Among the studied chamomile extracts, the aqueous extract at 80 \({}^{\circ}\)C presented higher total phenolic content in comparison with the extract at 100 \({}^{\circ}\)C, which contained the half-value, whereas at 25 \({}^{\circ}\)C did not detect phenolic content. Previously published data also reported that in cases of chamomile infusions at different temperatures total phenolic content was decreased in the following order: 80 \({}^{\circ}\)C \(>\) 100 \({}^{\circ}\)C [1]. In contrast to the obtained results in this investigation, another study reported that chamomile infused at 100 \({}^{\circ}\)C exhibited significantly higher total phenolic content than chamomile infused at 80 \({}^{\circ}\)C, but also reported that aqueous chamomile extracts had maximum total phenol concentration and minimum turbidity when extracted at 90 \({}^{\circ}\)C for 20 min [24]. Moreover, the obtained value of total phenolic content of chamomile aqueous extract at 80 \({}^{\circ}\)C (0.165 mg GAE/mL) was higher in comparison with the results of other literature sources' reports on chamomile aqueous extracts prepared at 100 \({}^{\circ}\)C with 0.102 mg GAE/mL, 0.115 mg GAE/mL, and 0.123 mg GAE/mL, respectively [25; 26; 27]. Concerning sage aqueous extracts, the extraction temperature had an effect on total phenolic content, showing that the most abundant content (between the temperatures 25, 80, and 100 \({}^{\circ}\)C) was obtained at 80 \({}^{\circ}\)C. In comparative studies, aqueous extracts of sage prepared at 100 \({}^{\circ}\)C had also demonstrated less total phenolic content in relation to the tested aqueous extract of sage at 80 \({}^{\circ}\)C [13; 25]. In addition, extraction with hot water (80 \({}^{\circ}\)C) differs significantly from other sage infusion preparation techniques in total phenolic content [5]. [PERSON] at al. concluded that total phenolic content in water extracts of sage increased slightly with the increase of extraction temperature [12]. Sage aqueous extract yielded higher total phenolic content at 25 \({}^{\circ}\)C than at 100 \({}^{\circ}\)C. Water as a polar solvent at room temperature can extract polar compounds. Moreover, due to the decrease of water polarity at higher temperatures, its capability to dissolve polar compounds is reduced [18]. In all the cases, increasing the extraction temperature from 25 \({}^{\circ}\)C to 80 \({}^{\circ}\)C caused extracts yielded with higher phenolic content. These results were explained by [PERSON] at al. who also studied sage aqueous extracts, reporting that the mass fraction of total polyphenols significantly depends on the extraction temperature [12]. An earlier research paper demonstrated that an increase in water temperature also causes a reduction in surface tension and viscosity, so the diffusion rate and the rate of mass transfer during extraction was increased [28]. [PERSON] and [PERSON] also mentioned that cool water extracted significantly less polyphenols than boiling water from dried Phylanthus amarus plant material [29]. A previous study on the effect of extraction temperature on polyphenol yield of papaya leaves aqueous extracts showed that the extraction yield of polyphenols increased when the extraction temperature increased from 50 to 70 \({}^{\circ}\)C. The yield however decreased when the temperature was raised to 100 \({}^{\circ}\)C, a result that may be linked to thermally-induced decomposition [30]. [PERSON] et al. explained the effect of elevated temperatures on the decrease of total phenolic content by trigger competing processes (decomposition and epimerization) [31].