Theoretical Investigation of Structural and Optical Peculiarities of Bikaverin Fungal Pigment in Chloroform Solution

Bikaverin is a polyketide pigment metabolite produced by certain <i>Fusarium</i> genus fungi. It has a number of promising applications due to its biological properties, including a cytotoxic effect against certain cancer cell lines, antioomycete and nematicidal biological activity, and potential antiviral activity. A more accurate structural characterization using quantum chemical calculation methods may facilitate the study of other useful biological properties. Therefore, in this study, a single-molecule density functional theory study of bikaverin in chloroform solvent was conducted. In addition to the lowest state, two rotational conformers with energies higher by 0.74 and 0.32 kcal/mol were found, as well as the presence of a stable low-energy tautomeric state higher in energy by 1 kcal/mol. IR absorption spectra and UV-visible electronic absorption spectra were modeled for certain states. The attribution of the observed spectral peculiarities was performed. Vibrational modes and peaks sensitive to structural peculiarities were proposed for the IR absorption spectra of various energy states. The results obtained can be used to further control the structure of bikaverin and its derivatives.