Dopamine docking studies of biologically active metabolites from Curcuma longa L.

The dopaminergic system is involved in a wide range of neuropsychiatric and neurodegenerative disorders. The lack of receptor subtype specificity is related to several pharmacological side effects that are observed during therapy among parkinsonian and schizophrenic patients. It is of paramount importance to search for new compounds that act on dopamine receptors with therapeutic potential, higher clinical effectiveness, and fewer adverse effects. In the present study, we performed a molecular docking study of D2, D3, and D4 receptor interactions with 92 metabolites from Curcuma longa using an in silico approach. We sought to identify compounds for possible drug development. A virtual library of compounds was built using molecules that were identified in the phytochemical characterization of C. longa. Protocols that were validated by redocking were applied to a virtual scan of this library using the Autodock-v4.2.3, Autodock Vina, and Molegro-v6.0 Virtual Docker programs, with four repetitions each. The three-dimensional structures of D2, D3, and D4 receptors in complex with risperidone, eticlopride, and nemonapride were obtained from the Protein Data Bank. Four compounds—stigmasterol, β-sitosterol, cholest-5-en-3-one, and cholestan-3-ol,2-methylene-(3β, 5α)—were the most likely to bind D2, D3, and D4 dopamine receptors, suggesting their potential for possible drug development.