Berberine alkaloid: Quantum chemical study of different forms by the DFT and MP2 methods

We investigated stable structures and electronic properties for berberine cation as well as possible ammonium, carbinol and amino-aldehyde forms of protoberberine salts in the presence of hydroxyl ions by DFT and MP2 methods. Their optimized structures are nonplannar propeller-twisted and buckled. The most stable form is the amino-aldehyde one.