Quantum Chemistry Calculation on Demethylated Metabolites of Aconitine

This study was aimed at evaluating the metabolites of aconitine by quantum chemistry calculation. The geometries of possible metabolites were optimized by using the density functional theory at B3LYP/6-31G(d) level. The energies of possible metabolites and hydrolysis reactions were obtained. Solvation effects were calculated by using IEFPCM. A comparison among the four possible reaction energies showed that the metabolites of aconitine were identified as 16-O-demethylaconitine and 16-O-demethylbenzoylaconine. The energy difference of possible metabolites was increased in the aqueous solution. It was concluded that the metabolites identified by quantum chemistry calculation are the same as those deduced by fragmentation regularity of mass spectrometry. Metabolites of aconitine can be studied by a combination of HPLC-MSn and quantum chemistry calculation.