## 4 Discussion  
### Chemical Characteristics of Raw Material  
The infloreserences of mountain arnica are a very rich source of SLs and contain higher amounts of this metabolite than the level of approximately 0.1% detected in whole \(A\). _montana_ plants [11]. The SL content was within the ranges presented by other studies: [PERSON] et al. [7]--from 0.45% to 1.51%, [PERSON] et al. [36]--from 0.54% to 1.50%, and [PERSON] et al. [37]--from 0.40% to 1.55%, and definitely higher than those reported by [PERSON] et al. [38]--from 0.66% to 0.94%. Compared to the standards (minimum: 0.40%) presented in the Polish Pharmacopoeia VIII, the contents of these compounds were two-fold higher in the RM collected in the yellow bud stage and over three-fold higher in the material harvested in full flowering and at the end of flowering [33]. Our previous research revealed that nitrogen fertilization was a significant factor increasing the SL content in infloresences [3]. The stages of development clearly modified the concentration of SLs in the infloresences (Table 1), and the highest SL content was observed under full flowering (1.35%) and at the end of flowering (1.36%). A similar response of different plant species was reported earlier [38]. In a study on the localization of sesquiterpene lactone biosynthesis in mountain arnica flowers, [PERSON] et al. [12] showed that the lactone concentration increased from the top of the corolla to the ovary of single florets, with the pappus calyx as a source of their production. Therefore, the highest content of SLs is exhibited by \(A\). _montana_ infloresences at the end of flowering and possibly by the achene pappus, where the compounds may serve as protection against diseases [39].  
Figure 7: PCA analysis of the apoptosis (%) and necrosis (%) of the SW620 cell line induced by the ethanol and water extracts at the concentration of 1 \(\mu\)L/mL, and the chemical characteristics of \(A\). _montana_ raw material. SLs—sesquietrepene lactones; FS—flavonoids; EO—essential oil; EYB—ethanol extract prepared from infloresences in the stage of yellow buds; EBF—ethanol extract prepared from infloresences at the beginning of flowering; EFF—ethanol extract prepared from infloresences in full flowering; EEF—ethanol extract prepared from infloresences at the end of flowering; WYB—water extract prepared from infloresences in the stage of yellow buds; WBF—water extract prepared from infloresences in full flowering; and WEF—water extract prepared from infloresences at the end of flowering.  
The stages of development also clearly influenced the content of flavonoids in the armica infloresresences (Table 1). Their contents ranged from 0.43% DM at the end of flowering to 0.69% under full flowering, which confirms earlier findings. The data presented in the literature have also indicated that flavonoid compounds and SLs in _Arnicae anthodium_ can be modified using different cultivation models [9] and plant development stages [38]. The present study has confirmed that the highest content of these metabolites is stored in infloresences under the full flowering stage.  
The EO quantity in RM is significantly dependent on the level of infloresence maturity, along with nitrogen fertilization [3; 38]. The present results showed that the stages of development significantly modified the EO content in armica infloresences as well. The EO concentration in the armica infloresences analyzed in our study ranged from 0.19% to 0.29% (Table 1). The content of this SM in the infloresences was higher than that reported from Serbia [40] and Lithuania [41]. Analyses of its concentration in different plant parts showed higher EO content than in _A. montana_ achenes [23], but lower than in underground parts of plants cultivated in Poland [24] and Serbia [42].