## 3 Results and Discussion  
### Antioxidant Activity and Phenolic Content  
Medicinal and aromatic plants serve as prospective sources of natural bioactive compounds--including phenolic compounds--which hold significant potential for applications in the pharmaceutical, cosmetic, and food industries [5; 11; 28]. Particularly rich in these compounds are plants of the Lamiaceae family, which exhibit high biological activity. We have shown two Lamiaceae species--_T. vulgaris_ and _S. scardia_--to have significant phytochemical potential, and found differences between the extraction efficiency, chemical compositions and the antioxidant activities of the herb extracts derived from them (Tables 1-3). Sideritis extracts were found to have a higher total polyphenols content and total phenolic acids content, as well as better antioxidant activity (DPPH), compared to thyme extracts. Conversely, thyme extract had higher total flavonoids content and showed more antioxidant activity (FRAP) than sideritis extract. A high total polyphenols content in extracts is not necessarily accompanied by a high total flavonoids content, as the proportions of specific flavonoids in the total polyphenols content can vary [10]. _T. vulgaris_ is an established medicinal plant with notable antioxidative capacity [29]. [PERSON] et al. [30] reported thyme extracts MeOH as having the highest antioxidative capacity, exceeding that of other plants, \(\alpha\)-tocopherol and BHA. Antioxidant activity can also be estimated in MeOH extracts using ascorbic acid or total polyphenols content as a proxy measure, due to the strong correlation [25]. [PERSON] et al. [31] established that aqueous and EtOH thyme extracts have high antioxidant activity in terms of DPPH and ABTS radical scavenging activity, reducing potential, the inhibition of linoleic acid peroxidation, and iron/copper ion-reducing capacity. The differences in the chemical composition and antioxidant activity between the extracts under study were also attributed to the type of solvent (ACT, MeOH, EtOH-H\({}_{2}\)O, and EtOHAc) (Tables 1 and 2). Whereas both MeOH extracts (sideritis/ thyme) assayed had a similarly high total polyphenols content, the TMeOH proved superior to sideritis (SMeOH) in terms of total phenolic acids content (141.09 mg CA/g EX) and total flavonoids content (15.7 mg QE/g EX). [PERSON] et al. [32] compared the composition of two methanol extracts--one from saliva and one from thyme--and found that the saliva extract contained more total flavonoids (4.11 mg-QE/g-DW), but the thymi extract had more total polyphenols (8.89 mg-GAE/g-DW) and an improved extract yield (21.81%). In our study, the EtOH-H\({}_{2}\)O performed the best in terms of extraction yield, at 34.06% (thyme) and 32.14% (sideritis), followed by MeOH (31.05% sideritis and 27.82% thyme) (Table 1), which exhibited the highest antioxidant activity when measuring DPPH activity (Table 2). However, the activity of the 1% vitamin C solution, used as a control, was 90.03%. [PERSON] et al. [33] obtained the highest yield, at 46%, for the n-hexane fraction--conversely, however, the fraction exhibited no antioxidant activity and contained few phenolic compounds and flavonoid compounds. The EtOHAc fraction exhibited strong antioxidant activity, DPPH, and ABTS. The EtOHAc, butanol, and H\({}_{2}\)O fractions had more total polyphenols and total flavonoids, and higher antioxidant activity, compared to the n-hexane. This suggests that antioxidant activity, DPPH, ABTS, and FRAP are a function of secondary metabolites (phenolic compounds or flavonoid compounds). _S. scardia_ is one of the most bioactive and versatile medicinal plants. Its multi-tiered health benefits stem from the presence of phenol compounds--especially total phenolic acids content--in _S. scardia_ extracts [34]. Sideritis extracts possess remarkable DPPH scavenging activity and ensure lipid peroxidation inhibition. Furthermore, Sideritis plants with high levels of polyphenic compounds also exhibit the highest antioxidant activity [35].