## 4 Discussion  
There has been an increasing number of free radicals in cells due to current factors such as stress, malnutrition, sedentary lifestyles, and environmental pollution. This has led to an increase in diseases such as diabetes, hypertension, and cancer. Natural antioxidants play an important role in removing free radicals that have accumulated in the body. Natural antioxidants are obtained from parts of plants such as leaves, flowers, and seeds. Therefore, this study aimed to investigate the antioxidant and anticancer properties, phenolic compounds, and content profile of the _H. salsolifolium_ plant, which has not been previously studied, for use in the treatment of various diseases, especially cancer. To determine the biologically active substances, various extracts were made from the _H. salsolifolium_ plant. The results of the study showed that the highest total phenolic content (68.9 \(\pm\) 3.44 GAE mg/g) and total flavonoid content (104.69 \(\pm\) 5.23 QAE mg/g) were found in the methanolic extract. Similarly, in a study by [PERSON] et al., high total phenolic content and total flavonoid content were found in the methanolic extract [31]. In parallel with the current study, [PERSON] et al. also studied Hypericum species and reported that levels of phenolic substances were higher in the methanolic extract than in the other extracts [32]. Figure 4: The effect of _H. salsolifolium_ extract on A549 cell apoptosis. Figure 5: Demographic chart of cell cycle results in A549 cell line. The DPPH radical is a valid compound that reacts with antioxidants and provides information about activation. In the current study, the methanolic extract had the highest activity in the DPPH assay (66.14 \(\pm\) 3.30 mg Trolax/g). A previous study also examined Hypericum species and reported that the radical scavenging activation value of the methanolic extract in the DPPH assay was higher than that in the other extracts, similar to the current study results [33]. The ABTS radical also reacts with antioxidants and provides information about activation. In the current study, although the activity value in the ABTS assay was the highest for the aqueous extract, it was found to be close to that for the methanolic extract (75.01 \(\pm\) 3.75 and 73.38 \(\pm\) 3.66 mg Trolax/g, respectively). A previous study also showed that the activation values of aqueous and methanolic extracts in Hypericum species were close to each other according to the ABTS assay [33]. According to research on Hypericum species, the activation value of radical removal for the aqueous extract in the ABTS assay was higher than for the other extracts [34]. The reduction potential of FRAP by the _H. salsolifolium_ extracts was determined with iron-III ion. In the current study, the activation value of the methanolic extract was found to be highest in the FRAP assay (308.21 \(\pm\) 15.41 mg Trolax/g). In a study of Hypericum species, the activation value of the methanolic extract in the FRAP assay was higher than that of the other extracts [35]. The reduction potential of the _H. salsolifolium_ extracts in the CUPRAC assay was determined with copper-II ion. In the current study, the activation value of the aqueous extract was found to be highest in the CUPRAC assay (87.94 \(\pm\) 4.39 mg Trolax/g). A previous study also found that the activation value of the aqueous extract in the CUPRAC assay was higher than that of the other extracts [34]. In the phenolic compound content analysis performed on the methanolic extract of the _H. salsolifolium_ plant in the current study, mainly syringe acid (1714.43 \(\mu\)g/L) and vanillic acid (1577.83 \(\mu\)g/L) were found to have high levels. Similarly, syringic acid and vanillic acid were determined as the main phenolic compounds in a study of Hypericum species [36].