Next Article in Journal
Nutrition Quality Parameters of Almonds as Affected by Deficit Irrigation Strategies
Previous Article in Journal
Novel Derivatives of Deoxycholic Acid Bearing Linear Aliphatic Diamine and Aminoalcohol Moieties and their Cyclic Analogs at the C3 Position: Synthesis and Evaluation of Their In Vitro Antitumor Potential
Open AccessArticle

Molecular Structure and Antioxidant Properties of Alkali Metal Salts of Rosmarinic Acid. Experimental and DFT Studies

1
Department of Chemistry, Biology and Biotechnology, Bialystok University of Technology, Wiejska Street 45E, 15-351 Bialystok, Poland
2
Institute of Chemistry, University of Bialystok, Ciolkowskiego Street 1K, 15-245 Bialystok, Poland
*
Author to whom correspondence should be addressed.
Molecules 2019, 24(14), 2645; https://doi.org/10.3390/molecules24142645
Received: 2 July 2019 / Revised: 16 July 2019 / Accepted: 17 July 2019 / Published: 21 July 2019
The 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. View Full-Text
Keywords: rosmarinates; IR; Raman; NMR; DPPH; FRAP; DFT calculations rosmarinates; IR; Raman; NMR; DPPH; FRAP; DFT calculations
Show Figures

Graphical abstract

MDPI and ACS Style

Świsłocka, R.; Regulska, E.; Karpińska, J.; Świderski, G.; Lewandowski, W. Molecular Structure and Antioxidant Properties of Alkali Metal Salts of Rosmarinic Acid. Experimental and DFT Studies. Molecules 2019, 24, 2645.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Search more from Scilit
 
Search
Back to TopTop