Molecular Structure and Antioxidant Properties of Alkali Metal Salts of Rosmarinic Acid. Experimental and DFT Studies
Renata Świsłocka , Ewa Krystyna Regulska , Joanna Karpińska , Grzegorz Świderski , Włodzimierz Lewandowski
AbstractThe molecular structure of alkali metal rosmarinates was studied in comparison to rosmarinic acid using FT-IR, FT-Raman, 1H and 13C NMR spectroscopy, as well as density functional theory (DFT) calculations. The B3LYP/6-311+G(d,p) method was used to calculate optimized geometrical structures of studied compounds, atomic charges, dipole moments, energies, as well as the wavenumbers and intensities of the bands in vibrational and NMR spectra. Theoretical parameters were compared to experimental data. Antioxidant activity was determined using two spectrophotometric methods: (i) Assessing the ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) stable radical and (ii) assay of antioxidant power of ferric ions reducing (FRAP). The linear correlations were found between HOMO–LUMO (highest occupied molecular orbital–lowest unoccupied molecular orbital) energy gap and the reducing power expressed as FRAP (R = 0.77) as well as between IC50 values (the ability of quenching DPPH radicals) and Δνas-s(COO) in IR spectra (differences between asymmetric and symmetric stretching vibrations bands) (R = 0.99). Photochemical properties of studied compounds were also evaluated. The influence of alkali metal on the electronic system of the rosmarinic acid molecule was discussed.
|Journal series||Molecules, ISSN 1420-3049, (N/A 100 pkt)|
|Publication size in sheets||1.05|
|Internal identifier||ROC 19-20|
|License||Journal (articles only); published final; ; with publication|
|Score||= 100.0, 12-02-2020, ArticleFromJournal|
|Publication indicators||: 2017 = 1.146; : 2018 = 3.06 (2) - 2018=3.38 (5)|
* presented citation count is obtained through Internet information analysis and it is close to the number calculated by the Publish or Perish system.