## 4 Discussion
### Correlation of TPC with Antioxidant and AChE Inhibitory Activities  
Antioxidant activities, as assessed through DPPH, ABTS, and FRAP assays, display significant correlations with TPC, underscoring the central role of phenolic compounds in determining radical scavenging capacity, reducing power, and overall antioxidant potential. DPPH assay, which measures free radical scavenging activity based on IC\({}_{50}\) values, demonstrates a strong negative correlation with TPC (\(r=-0.787\), \(p=0.007\)). This finding suggests that higher TPC is associated with lower IC\({}_{50}\) values, reflecting stronger antioxidant activity. This relationship can be attributed to the ability of phenolic compounds to donate electrons or hydrogen atoms, neutralizing free radicals effectively. Similarly, ABTS assay also reveals a strong negative correlation with TPC (\(r=-0.732\), \(p=0.016\)). Although DPPH and ABTS employ distinct radical systems, the consistent trends between the two assays reinforce the role of phenolic content as a critical determinant of antioxidant efficacy across varying methodologies. FRAP assay, which evaluates reducing power, exhibits the strongest positive correlation with TPC (\(r=0.969\), \(p<0.0001\)). This indicates that higher TPC contributes directly to an increased capacity to reduce Fe\({}^{3+}\) ions to Fe\({}^{2+}\) ions, a key indicator of reducing power. This robust correlation suggests that phenolic compounds, through their hydroxyl groups, serve as potent electron donors, thereby enhancing the antioxidant potential of the samples. Among the antioxidant activities, the FRAP assay's relationship with TPC highlights the pivotal role of phenolics in governing reducing power. In addition to antioxidant activity, TPC also correlates significantly with anti-AChE activity, as assessed by AChE IC\({}_{50}\) values. The positive correlation between TPC and AChE inhibitory activity (\(r=0.818\), \(p=0.004\)) reflects the contribution of phenolic compounds to the inhibition of AChE, an enzyme associated with neurodegenerative disorders like Alzheimer's disease. Phenolic compounds are known to interact with cholinesterase  
Figure 5: HPTLC–DPPH fingerprint (white light) for _Acer_ (A1–A10) samples and phenolic acids reference bands. CAF: caffeic acid; CGA: chlorogenic acid; COU: \(p\)-Coumaric acid; GAL: gallic acid; PRO: protocatechic acid. enzymes through various mechanisms, including hydrogen bonding, hydrophobic interactions, and \(\pi\)-\(\pi\) stacking. This finding underscores the dual role of phenolic content in contributing not only to antioxidant properties but also to neuroprotective effects. The correlation between TPC and AChE inhibitory activity suggests that phenolics play a central role in modulating enzyme activity, further reinforcing their multifunctional bioactivity [57]. The interrelationships among the activities themselves provide additional evidence of the importance of TPC in driving biological efficacy. For example, the strong correlation between DPPH and ABTS activities (\(r\) = 0.983, \(p\) < 0.0001) reflects overlapping mechanisms of radical scavenging facilitated by phenolic compounds, while the significant relationship between FRAP and anti-AChE activities (\(r\) = 0.902, \(p\) = 0.00036) highlights the interconnectedness between reducing power and enzyme inhibition. This interplay suggests that phenolic compounds influence these activities through shared biochemical pathways, making TPC a comprehensive marker of their bioactive potential. Overall, these findings emphasize the critical role of TPC in determining the antioxidant and anti-AChE activities of phenolic-rich samples. The strong correlations between TPC and these bioactivities underscore its importance as a predictor of functional properties, with higher TPC levels associated with enhanced biological efficacy [57]. These insights have significant implications for the development and application of natural products, particularly in therapeutic contexts where antioxidant and neuroprotective properties are desired.