Table 4.
The BuChE inhibition docking scoresa and type of binding interactions of the major compounds of the essential oil & the standard (Rivastigmine).
| Comp | Binding energy (Kcal/mol)a (docking score) | Type of binding interactions |
|---|---|---|
| Rivastigmine | − 13.7 | Interaction with a water molecule of the binding site that form hydrogen bond with Asp70 and Ser79 |
| Strong hydrophobic interaction with Trp82, His438, Gly116 and Phe329 | ||
| Ah major components | ||
| Caryophyllene | − 8.9 | Strong hydrophobic interaction with Trp82 and His438 |
| Caryophyllene oxide | − 12.0 | Interaction with a water molecule of the binding site that form hydrogen bond with Asp70 and Ser79 |
| Strong hydrophobic interaction with Trp82, His438 and Phe329 | ||
| ( +)- Sabinene | − 6.6 | Strong hydrophobic interaction with Trp82 and His438 |
| D-limonene | − 6.7 | Strong hydrophobic interaction with Trp82 and His438 |
| Alpha-Copaene | − 8.6 | Strong hydrophobic interaction with Trp82 and His438 |
| Beta-pinene | − 7.0 | Strong hydrophobic interaction with Trp82 and His438 |
| Trans-verbenol | − 7.8 | Interaction with a water molecule of the binding site that form hydrogen bond with Asp70 and Ser79 |
| Strong hydrophobic interaction with Trp82 and His438 | ||
| Alpha-pinene oxide | − 9.5 | Interaction with a water molecule of the binding site that form hydrogen bond with Asp70 and Ser79 |
| Strong hydrophobic interaction with Trp82, His438 and Phe329 | ||
Significant values are in bold.
Rivastigmine was used as reference butyryl choline esterase inhibitor compound.
Docking was carried out following the reported procedures27 against the BuChE enzyme pocket (PDB code ID: 4BDS).
aMore negative score refers to better capability of a molecule to dock with the target and make more desirable interactions.