## 3 Results
### PLA2 Interactions  
The interaction parameters of the selected terpenes with PLA2, compared to AA, are summarized in Table 4.  
Limonene (\(-6.58\) kcal/mol) exhibits the lowest binding energy, followed by menthol (\(-6.57\) kcal/mol) and AA (\(-6.23\) kcal/mol), indicating stable interactions with PLA2. The remaining terpen also show good affinity, with \(\beta\)-pinene presenting the highest binding energy (\(-5.28\) kcal/mol), which may indicate weaker interaction with the enzyme.  
Among the terpenes, limonene (14.99 \(\upmu\)M) and menthol (15.22 \(\upmu\)M) exhibit the lowest Ki values, identifying them as the most promising potential inhibitors of PLA2. In contrast, \(\beta\)-pinene shows the highest Ki value (134.07 \(\upmu\)M), indicating a weaker affinity for the enzyme.  
High RMSD values are recorded for camphor (96.944 A), linalool (96.905 A), and menthol (98.205 A), suggesting significant structural changes upon binding to PLA2. Notably, \(\alpha\)-pinene (110.729 A) and \(\beta\)-pinene (100.997 A) exhibit the highest RMSD values, indicating pronounced flexibility during interaction.  
The highest torsional energies are observed for \(\alpha\)-pinene (+1.49 kcal/mol) and AA (+4.47 kcal/mol), suggesting greater conformational flexibility. In contrast, menthol (+0.60 kcal/mol) and limonene (+0.26 kcal/mol) display lower torsional energies, which may indicate more stable conformations when bound to PLA2.  
AA exhibits the lowest unbound energy (\(-1.91\) kcal/mol), consistent with its high affinity for PLA2. It is followed by \(\alpha\)-pinene (\(-0.26\) kcal/mol) and menthol (\(-0.17\) kcal/mol).  
The analysis reveals that limonene and menthol have the lowest binding energies, suggesting stable interactions with PLA2. These two compounds also demonstrate the lowest Ki values, identifying them as potential inhibitors of the enzyme. In contrast, \(\beta\)-pinene shows the weakest affinity, likely due to its high Ki value.  
A 3D visualization of the interactions between the terpenes, AA, and the PLA2 enzyme is presented in Figure 4. Ligands are shown in the ball-and-stick format, surrounded by a space-filling surface representation of the protein to illustrate spatial accommodation and  
\begin{table}
\begin{tabular}{l c c c c c c c} \hline \hline
**PLA2** & **Limonene** & **Camphor** & **Linalool** & **Menthol** & \(\alpha\)**-Pinene** & \(\beta\)**-Pinene** & **AA** \\ \hline Conformations & 19 & 6 & 11 & 6 & 8 & 25 & 2 \\ \hline RMSD from & & & & & & & \\ Reference Structure & 89.108 A & 96.944 A & 96.905 A & 98.205 A & 110.729 A & 100.997 A & 98.253 A \\ \hline Binding Energy & \(-6.58\) & \(-5.94\) & \(-6.00\) & \(-6.57\) & \(-6.49\) & \(-5.28\) & \(-6.23\) \\ kcal/mol & kcal/mol & kcal/mol & kcal/mol & kcal/mol & kcal/mol & kcal/mol & kcal/mol \\ \hline Inhibition & & & & & & & \\ Constant, Ki & 14.99 \(\upmu\)M & 44.43 \(\upmu\)M & 39.77 \(\upmu\)M & 15.22 \(\upmu\)M & 17.50 \(\upmu\)M & 134.07 \(\upmu\)M & 27.27 \(\upmu\)M \\ \hline Total Internal Energy & \(-0.13\) & +0.00 & +0.00 & \(-0.17\) & \(-0.26\) & +0.00 & \(-1.91\) \\ kcal/mol & kcal/mol & kcal/mol & kcal/mol & kcal/mol & kcal/mol & kcal/mol \\ \hline Torsional Free & +0.30 & +0.00 & +0.00 & +0.60 & +1.49 & +0.00 & +4.47 \\ Energy & kcal/mol & kcal/mol & kcal/mol & kcal/mol & kcal/mol & kcal/mol & kcal/mol \\ \hline Unbound Energy & \(-0.13\) & +0.00 & +0.00 & \(-0.17\) & \(-0.26\) & +0.00 & \(-1.91\) \\ kcal/mol & kcal/mol & kcal/mol & kcal/mol & kcal/mol & kcal/mol & kcal/mol \\ \hline \hline \end{tabular}
\end{table}
Table 4: In silico docking results for interactions between selected terpen and PLA2: binding energy, conformational parameters, inhibition constants (Ki), and energy descriptors compared to arachidonic acid (AA).  
surface contact. The visualization highlights the degree of penetration and positioning of each ligand within the catalytic pocket of PLA2.