## 3 Results and Discussion
### Selected Plant Growth Attributes
GAE/g and 30.2 mg/g in S1 (30 DAS) to 369.0 mg GAE/g and 224.2 mg/g in S3 (80 DAS), and these compound changes strongly influenced AOA (Figure 5C). DPPH and ABTS measured at 100 \(\upmu\)g/mL and 50 \(\upmu\)g/mL increased from 16.3 \(\pm\) 0.0% and 39.4 \(\pm\) 4.5% in S1 (30 DAS) to 61.1 \(\pm\) 1.0% and 65.0 \(\pm\) 0.7% in S3 (80 DAS). Natural antioxidants can delay or inhibit lipid oxidation by suppressing the initiation or propagation of oxidative chain reactions [46]. Phenolic compounds are widely recognized for their desirable antioxidant properties. They act as reducing agents, single oxygen quenchers, hydrogen donors, and chelating agents of metal ions [47; 48]. The antioxidant activity of phenolics typically depends on the arrangement and substitution pattern of hydroxyl groups, making the presence and proportion of active compounds crucial [46]. Although all plants in this study contained RA as the main component, their contributions to antioxidant activity were differently confirmed. According to the influence on the AOA of TPC and RAC, expressed as correlation coefficients, they could be divided into two major groups. The dominant group of the combination of phenolics included AR and SO, while the dominant group of RAC alone included OBP and MO. This was explained by the compound profiles and their respective antioxidant capacity in each plant species. For secondary metabolites of AR, numerous phenolics such as 4-hydroxybenzoic acid, chlorogenic acid, caffe acid, cinnamic acid, and flavonoids including quercetin, rutin, kaempfer, tilianin, and acacetin have been reported as well as RA [49; 50]. In particular, the amount and proportion of major phytochemicals such as tilianin, acacetin derivatives, and RA present in AR were found to vary [51; 52]. It was explained by the increase in RA and decrease in other components (quercetin, tilianin, acacetin, etc.) during the flower development process [49; 52]. The higher phenolic levels in flowers produced stronger antioxidant activity than in the stems and leaves, resulting in an improvement of the biological activities of the reproductive stage [53]. Therefore, the highest antioxidant activity observed at 70 DAS and the significant contribution of RA to this activity can be well explained by the entry into the reproductive stage. In the case of SO, the previous literature reported that carnosol [54], quercetin derivative [55], and campherd [56] are also included in SO as secondary metabolites. Furthermore, abietane-type di terpenoids, such as carnosol acid and carnosol, along with RA, significantly contribute to the antioxidant activities of SO [57]. However, during the transition from the vegetative stage to the reproductive stage, there is an opposite trend in the accumulation of active compounds, with an increase in phenolic diterpens (such as carnosol acid and carnosol) and flavonoids (such as apigenin, hispidulin, crismaritin, and naringin) and a decrease in RA [58]. Additionally, [PERSON] and [PERSON] [59] explained that flavonoids exhibit comparatively weaker antioxidant activity (AOA), while RA derivatives display stronger AOA, than Trolox in SO. During the experiment, SO did not enter the flowering period, so it was considered as a vegetative state with RA being dominant. Therefore, it was explained that the effect of RA on antioxidant activity was greater. Meanwhile, MO and OBP showed other antioxidant active compounds' effects on AOA. MO is known for containing RA as its main compound, along with other phenolic compounds including fertile acid, gallic acid, chlorogenic acid, syringic acid, p-counaric acid, and caffe acid, which are present in high proportions [60]. Caffeic acid, in particular, is found as another prominent phenolic in MO [61; 62] and is more effective in inhibiting lipid oxidation and oil-in-water emulsion oxidation activities than RA [63]. Phenolic compounds as well as flavonoids are important active compounds of MO, although their profiles vary depending on the variety. [PERSON] et al.