Background: The azadirachtin is a triterpenoid associated with growth inhibition
in several kinds of insects which cause epidemic diseases like Dengue, Chikungunya
and Malaria. Azadirachtin acts by inhibiting the Ecdysone Receptor (EcR), which is responsible
from larvae phase in insects. However, the interaction between the azadirachtin
molecule and the Ecdysone Receptor is unknown. In this work, we used the program Dock
Thor to generate several azadirachtin conformations inside the EcR binding site. The ten
most stable conformations were optimized with the ONIOM approach present in the
Gaussian 09 program. The interaction energy was calculated between the azadirachtin
molecule and EcR receptor. Theoretical calculation shows that the azadirachtin molecule
interacts with the same amino acids present in the ecdysone EcR interaction. These results
will be useful to design new EcR inhibitors, which can be used in the control of some diseases
based on insect proliferations.
Objective: To understand the interaction between the natural insecticide azadirachtin and
the Ecdysone Receptor.
Methods: A combination of Dock Thor program with QM-MM calculation was used in order
to obtain the most favorable molecular structures.
Results: The hydrogens bond obtained by Dock Thor Program combined with QM-MM
calculation suggest the azadirachtin interact with EcR in the same way that ecdysone molecule.
Conclusion: The interaction mode that the molecule azadirachtin inhibits EcR in order to
avoid insect proliferation was described.