Spectroscopic, quantum chemical and molecular docking studies on friedelin, the major triterpenoid isolated from Garcinia imberti

Abstract

Friedelin, a Garcinia imberti isolate, was subjected to a detailed theoretical study using the density functional theory. Theoretical calculations, such as optimized geometry, electronic, vibrational spectroscopic, intermolecular interactions, and insilico screening were performed. DFT at hybrid functional B3LYP was chosen, and the 6–311++G(d, p) level of theory was used for all simulations. The first three rings of the compound are in chair conformation (trans arrangement), while the remaining two rings are in boat conformation (cis arrangement). Transannular, flagpole, and stereo electronic hyperconjugative interactions are observable throughout the optimal geometry because of the conformation therein. Non-covalent H...H interactions is also confirmed by Hrishfeld surface analysis. NBO and NPA analyses have confirmed stereo electronic hyperconjugative interactions and C-H...O intramolecular hydrogen bonding interactions. The estimated vibrational wavenumbers and the experimentally determined values have an excellent correlation. The TD-DFT computations were performed both in solvent (chloroform) and gaseous phase, and agree with the experimental values. The molecule was tested insilico against tuberculosis protein 4FDO using the Schrodinger suite's Glide docking software. After the docking studies, the compound's drug-likeness and ADMET predictions were calculated, and the results indicated that it could be exploited as a tuberculosis treatment option.