# Antioxidant Activity According to the Planting Interval and Collecting Time of _Rosa daavrica_
## 4 Discussion  
_R. davurica_ can be planted all over South Korea, but it thrives on rich, loamy soil. The best planting interval is indicated to be 120 cm row spacing and 100 cm inter-row spacing. According to the South Korean Ministry of Food and Drug Safety, _R. davurica_ can only be ingested in the form of fruit, buds, and petals. [PERSON] et al. discovered that the vitamin content of _R. davurica_ varied based on the portion of the plant taken, with the leaves having the highest concentration [15]. This means that to ensure its best utilization as a food source, the large-scale harvesting of components like buds and leaves is required. However, when _R. davurica_ is planted at the recommended density, bud size reduces dramatically. As a result, this study was carried out to identify whether the production of _R. davurica_ buds and leaves improved depending on the reproductive density (120 \(\times\) 50 cm, 120 \(\times\) 100 cm) and harvest date (May and September). The verification revealed considerable variations in the amounts of buds and leaves at various planting intervals and harvest dates. Regardless of harvest date, decreasing the planting interval from 100 cm to 50 cm boosted bud and leaf yields by more than 100% (Table 1). When harvest date was removed, September showed a considerable increase in yield for both buds and leaves, although statistical significance was not reached. As a result, it is claimed that planting interval influences yield more than harvest date. In order to enhance the cultivation efficiency of _R. davurica_, a 50 cm planting interval is suggested as a possibly better option than the standard 100 cm spacing. Furthermore, when the ethyl gallate content of _R. davurica_ buds and leaves was evaluated using HPLC, there were no variations in component levels based on planting interval or harvest date (Figure 2). This means that the two previously mentioned parameters have no effect on the composition of _R. davurica_ buds and leaves. Numerous recent studies have indicated that flavonoid molecules, which are widely distributed in plants, play a variety of physiological roles and have important properties, including antioxidant activity [16]. Furthermore, the phenolic hydroxyl (OH) groups found in phenolic compounds are known to have physiological features such as antioxidant, anticancer, and antibacterial actions via binding to proteins and other materials [17; 18]. In general, studies have indicated that as total polyphenol concentration increases, so do physiological activities such as antioxidant properties [19]. The purpose of this study was to determine the changes in the overall flavonoid and polyphenol contents of _R. davurica_ buds and leaves based on planting interval and harvest date (Table 2). According to our comparison of the experimental results, the flavonoid contents of _R. davurica_ bud and leaf extracts had no significant differences based on planting interval and harvest date. [PERSON] et al. 's study observed that the flavonoid content of _Turnera diffusa_ leaves was 108.8 mg QE/g extract [20]. Furthermore, [PERSON] et al. observed that the polyphenol content of _Centella asatica_ ranged between 2.14 and 2.82 mg GAE/g extract [21]. In this experiment, the flavonoid and polyphenol contents of _R. davurica_ bud and leaf extracts were greater. Figure 5: Effects of planting interval and collecting time on SOD relative activity of _Rosa davurica_ buds (**a**) and leaves (**b**). MB, May bud; SB, September bud; ML, May leaf; SL, September leaf. MB/ML/SB/SL-50 and MB/ML/SB/SL-100 refer to planting interval. All data are shown as the mean \(\pm\) SD. These results indicate that, depending on plant interval and harvest date, the _R. davurica_ bud and leaf extracts found in this study contain a rather high quantity of polyphenols. Furthermore, while planting interval had no effect on overall flavonoid and polyphenol concentrations, harvesting in September proved to be more successful overall.