## 3 Results
### MD Simulation and Stability
The overall movements that displayed an indirect correlation in the **4d_BSA complex remained consistent with those in the Aspirin complex. However, the movements indicating a negative correlation significantly increased, particularly in the regions marked by red boxes. Moreover, at the atomic level, the molecule **4d** formed a stable complex with the active site of BSA. The results of this study are in agreement with the molecular docking outcomes and the data from the dynamic simulations, confirming  
Figure 6: Evaluation of biomolecular stability during 300 ns of simulation, including RMSD, RMSF, Rg and SASA. The **4d_BSA complex is represented in green, while the Aspirin_BSA complex is shown in magenta. the ability of the proposed compounds to effectively inhibit the biological functions of the BSA protein. To examine the dynamics of the BSA protein following interactions with the Aspirin and **4d** molecules, we created a free energy landscape (FEL) to depict the changes in the BSA configurations. Two reaction parameters were chosen for the FEL: the RMSD of BSA, which indicates the stability of the protein over the 300 ns of the simulation, and Rg, which represents the BSA's folding state. Figure 8 presents the free energy landscape of the interactions between the BSA protein and the **4d** and Aspirin molecules. For **4d**, a significant energy well is observed at RMSD values of 0.10 and 0.32 nm, with Rg values of 2.66 and 2.77 nm. Similarly, the reference molecule Aspirin shows a prominent energy well at RMSD values of 0.12 and 0.31 nm, with corresponding Rg values of 2.64 and 2.77 nm. These results indicate that both **4d** and Aspirin exhibit stable binding conformations with the BSA protein, as reflected by the consistent energy wells. The slightly lower RMSD values for **4d** suggest a potentially more stable interaction compared to Aspirin, which aligns with its observed compactness in the free energy landscape. Additionally, the similar Rg values for both molecules indicate that the overall structural compactness of the protein-ligand complex remains comparable in both cases. This reinforces the potential of **4d** as a competitive molecule in binding stability and affinity when compared to Aspirin. Finally, the results of the free energy landscape (FEL) studies were particularly intriguing, as they provided a clear distinction between the biomolecular structures of the **4d** and Aspirin complexes. These findings align closely with the outcomes of the RMSD and DCCM analyses, further validating the structural differences and dynamics observed in the interactions. The MM-PBSA calculations were carried out to perform an extensive evaluation of the binding energies involved in the interaction between the two molecules and the BSA receptor, providing a detailed understanding of the forces that govern this interaction. The total binding energies of the **4d** and Aspirin molecules, calculated as \(-15.91\) and \(-14.25\) kcal.mol\({}^{-1}\) respectively, suggest that **4d** binds more strongly to the BSA receptor compared to Aspirin. This difference in binding energy indicates that **4d** may form a more stable complex with the protein, which could result in enhanced binding affinity and potentially greater inhibitory activity. The more negative binding energy of **4d** implies stronger intermolecular interactions. In contrast, the slightly higher binding energy of  
Figure 7: Cross-correlation maps based on C\(\alpha\) atom positions of the BSA protein: (**A**) **4d** and (**B**) Aspirin. Aspirin suggests that its interaction with BSA is less favorable, which could translate into a weaker or less stable binding. This analysis underscores the promising characteristics of **4d**, especially in the context of its biological activity, such as its potential as a drug candidate. Finally, the van der Waals interactions are the primary contributors to the stability of the formed complexes.