4-Nerolidylcatechol (4NRC), a secondary metabolite described as a potent antioxidant that presents anti-inflammatory, antimalarial, analgesic, and cytotoxic properties, has been receiving prominence in the catechol class. In this work, a theoretical DFT study of the vibrational, structural, and quantum properties of 4-nerolidylcatechol (4NRC) using the B3LYP/6-311G (2d,p) level is presented. The theoretical molecular geometry data were compared with the X-ray data of a similar molecule in the associated literature and a conformational study is presented, with the aim of providing a good comprehension of the 4NRC structural arrangement and stability. Also, HOMO-LUMO energy gap and natural bond orbitals (NBOs) were performed and discussed. The calculated UV spectrum showed similarity to the experimentally obtained data, with transitions assigned. The comparative IR studies revealed that intermolecular hydrogen bonds that stabilize dimeric forms are plausible and also allowed the assignment of several characteristic vibrations. Molecular docking calculations with DNA topoisomerase I-DNA complex (TOPO-I), glyceraldehyde 3-phospate dehydrogenase (GAPDH), andPlasmodium falciparumlactate dehydrogenase (PfLDH) showed binding free energies of −6.3, −6.5, and −7.6 kcal/mol, respectively, which indicates that 4NRC is a good competitive inhibitor for these enzymes.

A detailed structural analysis and spectral behavior of the glucoalkaloid strictosidine, a precursor of all monoterpene indole alkaloids, are discussed. The experimental NMR, FTIR, and UV results were compared to the theoretical DFT spectra calculated by Becke using the three-parameter Lee-Yang-Parr (B3LYP) function with 6-31G(d) and 6-311++G(2d,p) basis sets. The theoretical geometry optimization data were compared with the X-ray data for precursors and similar structures in the associated literature. The similarity between the theoretical and experimental coupling constants values made it possible to affirm the values of dihedral angles and their configuration, reinforcing findings from previous stereochemical studies. Theoretical UV analysis agreed well with the measured experimental data, with bands assigned. Calculated HOMO/LUMO gaps show low excitation energy for strictosidine, justifying its stability and reaction kinetics. The molecular electrostatic potential map shows opposite potentials regions that form hydrogen bonds that stabilize the dimeric form, which were confirmed by excellent agreement of the dimeric form theoretical wavenumbers with the experimental IR spectrum. ESI-MS/MS data revealed patterns for the fragmentation of the protonated strictosidine molecule outlined by an NBO study.