# From Forest Berry Leaf Waste to Micellar Extracts with Cosmetic Applications
## 3 Results and Discussion
### Active Ingredient Contents in Berry Plant Leaves
#### 3.1.2 Vitamin C Content, Oxidative Activity, and Total Polyphenolic Content in Berry Plant Leaves  
The cosmetics industry is increasingly focusing on plant-based raw materials, which typically contain numerous biologically active and readily available ingredients, including vitamins and antioxidants [52; 53]. Vitamin C and phenolic compounds are antioxidants that play a role in protecting the body against free radicals. Vitamin C is an essential active ingredient that, among its numerous benefits, strengthens blood vessel walls, soothes skin redness, accelerates healing processes, and provides mild exfoliation [54; 55]. An alternative indicator of antioxidant capacity is oxidative activity. It is measured by the degree of reduction of free radicals DPPH [29]. Table 4 presents the results of the measurements of the vitamin C content, oxidative activity, and total polyphenolic content levels in the studied berry plant leaves. An analysis of the vitamin C levels in the tested raw materials revealed that the wild strawberry leaves had the highest vitamin C content (6.813 mg per 100 g DM). The vitamin C levels in the blackberry and blueberry leaves were similar, with no statistically significant differences (Table 4). The content of vitamin C in plant-based raw materials is influenced by numerous factors. The key aspects include the plant variety, cultivation location and \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Plant material** & **Vitamin C Content** & **Oxidative Activity** & **Total Polyphenolic** \\  & **[mg/100 g DM]** & **[\% Inhibition] DPPH** & **Content** \\  & & & **[mg GAE/100 g DM]** \\ \hline _Fragaria vesca_ L. & 6.813 b \(\pm\) 0.090 & 92.51 a \(\pm\) 0.665 & 65.641 b \(\pm\) 4.82 \\ _Rubus fruticosus_ L. & 4.718 a \(\pm\) 0.010 & 92.88 a \(\pm\) 0.166 & 59.553 a \(\pm\) 1.85 \\ _Vaccinium myrtillus_ L. & 4.851 a \(\pm\) 0.269 & 96.21 b \(\pm\) 0.307 & 85.093 a \(\pm\) 1.65 \\  & & \(p\) & \\  & \(<\)0.001 & \(<\)0.001 & \(<\)0.001 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Vitamin C content, oxidative activity, and total polyphenolic content results. methods, regional climatic conditions, degree of ripeness at harvest, and the time and methods of transport, processing, and preservation [56]. These factors may have also contributed to the variations observed in the determination of the vitamin C content in the analyzed plant leaves. The study found that the blueberry leaves exhibited the highest reduction of DPPH free radicals (96.21%) and the highest total polyphenic content (85.093 mg GAE/100 g DM). These values were statistically significant when compared to the blackberry and wild strawberry leaves tested (Table 4). In the next stage of the study, a correlation analysis (Table 5) was conducted to determine the relationship between the antioxidant activity (DPPH) and vitamin C and the total polyphenic content in the leaves of three plant species (wild strawberry, blackberry, and blueberry leaves). The analysis aimed to determine which of these components play a dominant role in neutralizing free radicals and how their content affects the antioxidant capacity of the leaves studied. These results (Table 5) indicated very strong and statistically significant correlations between the level of phenolic compounds and antioxidant activity (r = 0.9488). This confirms the antioxidant properties of phenolic compounds proven in many articles [1; 32; 57] and indicates that they are the most important antioxidants of the analyzed leaves. The trend is also confirmed by the negative and statistically insignificant correlation (r = \(-\)0.5303) between the level of vitamin C and the ability of the tested leaves to neutralize DPPH radicals. The favorable results from a cosmetic point of view (Sections 3.1.1 and 3.1.2) obtained for the dried leaves prompted the assumption that these valuable components (micro- and macroelements and vitamin C) would also be present in micellar extracts made with them. This is an analogous assumption applied to antioxidant activity and total phenolic content.