Isolation, crystal structure, DFT calculation and molecular docking of uncinatine-A isolated from Delphinium...

The main objective of our present research work was to explore molecular insight for potentially active new acetylcholinesterase inhibitor from the aerial parts of Delphinium uncinatum. New norditerpenoid alkaloids, uncinatine-A, was isolated from the basic alkaloidal fraction of D. uncinatum, based on bioactivity guided isolation. The structure of uncinatine-A was determined through latest spectroscopic techniques including single X-Ray diffraction technique. The structural data and electronic properties of uncinatine-A was also calculated by Density Functional Theory (DFT) using B3LYP/6-31þ G (p) basis set. The isolated natural product was evaluated for their acetyl cholinesterase inhibitory potential in dose dependent protocol (62.5-1000 μg/mL), followed by molecular docking studies. Significant competitive type inhibition activity (IC_{50 =} 207.73 ± 0.3) was shown by isolated natural norditerpenoid against cholinesterase targets in comparison with standard drugs available in the market such as galanthamine. The molecular docking results showed that isolated natural product was well accommodated by AChE in the active site with docking scores -11.0326. This is the first report indicating uncinatine-A as a potent acetylcholinesterase inhibitor and can be used as a target drug in cerebral dementia and Alzheimer diseases.