The influence of metal ions on the structure parameters as well as some physical, chemical, and biological properties of biological active molecules were previously studied by our team. Data concerning the molecular structure of rosmarinic acid and its antioxidant activity are also available, but there is no information about alkali metal rosmarinates. Properties, biosynthetic pathway, and the determination of rosmarinic acid in plant extracts have already been described in the literature. reported that it might inhibit the metastasis of colorectal carcinoma. rosmarinic acid may be used as a potent chemopreventive agent in rat colon cancer. The antiviral, antiallergic, neuroprotective, antiinflammatory, anti-HIV, and antitumor effects of rosmarinic acid were described in the literature. Rosmarinic acid showed inhibitory and bactericidal exerts against some pathogenic bacteria, e.g., Staphylococcus epidermidis, Staphylococcus lugdunensis, Stenotrophomonas maltophilia, Enterococcus faecalis, Pseudomonas aeruginosa, Corynebacterium, Mycobacterium smegmatis, and Staphylococcus warneri. The antimicrobial activity was also studied.
LUMO AND HUMO SERIES
Its antioxidant activity is stronger than that of vitamin E and it is the highest in the series of hydroxycinnamic acid derivatives: Rosmarinic acid > chlorogenic acid > caffeic acid > ferulic acid > coumaric acid. Rosmarinic acid has a lot of interesting biological activities. Such a molecular structure entails specific properties of this compound. The molecule of rosmarinic acid contains carboxylic group, two aromatic rings A and A’ with the ortho-catechol structures, the unsaturated C=C bond, and the ester moiety ( Figure 1). Its structure was established as an ester of caffeic acid and 3,4-dihydroxyphenyllactic acid. The name of this compound comes from the plant from which rosmarinic acid was isolated for the first time (in 1958). It is commonly found in plants such as rosemary, sage, lemon balm, oregano, lavender, mint, and savory. Rosmarinic acid is a naturally occurring bioactive compound. The influence of alkali metal on the electronic system of the rosmarinic acid molecule was discussed. Photochemical properties of studied compounds were also evaluated. 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 IC 50 values (the ability of quenching DPPH radicals) and Δν as-s(COO) in IR spectra (differences between asymmetric and symmetric stretching vibrations bands) (R = 0.99). 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).
![lumo and humo lumo and humo](http://www.nanoer.net/ueditor/php/upload/image/20190212/1549971367794762.gif)
Theoretical parameters were compared to experimental data. 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. 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.