Mass Spectral Fragmentation of Pelargonium graveolens Essential Oil Using GC–MS Semi-Empirical Calculations and Biological Potential

Abstract

The volatile constituents of the essential oil of local Pelargonium graveolens growing in Egypt was investigated by gas chromatography–mass spectrometry (GC–MS), and the main constituents were citronellol (27.67%), cis-Menthone (10.23%), linalool (10.05%), eudesmol (9.40%), geraniol formate 6.87%, and rose oxide (5.77%), which represent the major components in the obtained GC total ion chromatogram. The structural determination of the main constitutes based on their electron ionization mass spectra have been investigated. The MS of these compounds are absolutely identical in mass values of peaks of fragment ions, where their relative intensities have minor differences. In the spectra of all studied compounds, the observed characteristic ions were [M-H2O]+ and [M-CH3]+. The latter has a structure with m/z 69, 83. Different quantum parameters were obtained using Modified Neglect of Diatomic Overlap (MNDO) semi-empirical method as total energy, binding energy, heat of formations, ionization energy, the energy of highest occupied molecular orbital (HOMO), the energy of the lowest unoccupied molecular orbital (LUMO), energy gap Δ, and dipole moment. The antibacterial and antifungal activities of P. graveolens essential oil and identified compounds were tested against wide collection of organisms. The individual identified compounds in the essential oil—citronellol, cis-Menthone, and linalool (except eudesmol)—showed comparable activity to antibiotics. The most active isolated compound was the citronellol and the lowest MIC was found against E. coli. The essential oil showed high antifungal effects and this activity was attributed to cis-Menthone, eudesmol, and citronellol (excluding linalool). cis-Menthone was the most active compound against selected fungi followed by the eudesmol The study recommends local P. graveolens and identified active compounds for further applications in the pharmaceutical industries.

Saudi Rosmarinus officinalis and Ocimum basilicum L. Polyphenols and Biological Activities

“…The absorbance was measured at 470 nm for β-carotene bleaching, at 517 nm for DPPH, and at 593 nm for FRAP. The FRAP reagent was prepared as described before [40][41][42][43]. Aliquots (100 µL) of leaf extracts/Trolox (Sigma-Aldrich, Berlin, Germany) were added to the reagent (3 mL), then mixed and incubated for 30 min at 37 • C. The calibration procedure of FRAP was done by applying serial dilutions of Trolox (0-0.5 mmol/L), as standard.…”

“…Bacterial isolates of L. monocytogenes (clinical isolate), S. aureus (ATCC 6538), E. coli (ATCC 35210) ria, B. cereus (ATCC 14579), P. aeruginosa (ATCC 27853), and M. flavus (ATCC 10240), were used in this assay. A microtiter plates based protocol (micro-dilution) was used following [7,[40][41][42], by preparing serial concentrations of the extracts that were mixed with bacterial inoculum of 1.0 × 10 4 CFU in each well with 100 µL tryptic soy broth per well, then incubated for one day at 37 • C on a rotary shaker. The minimum inhibitory concentration (MIC) was defined as the lowest concentration that caused no visible growth by binocular microscope.…”

Malus baccata var. gracilis and Malus toringoides Bark Polyphenol Studies and Antioxidant, Antimicrobial and Anticancer Activities

“…The bark extracts' bacterial control against Listeria monocytogenes (clinical isolate), Staphylococcus aureus (ATCC 6538), Escherichia coli (ATCC 35210), Bacillus cereus (ATCC 14579), Pseudomonas aeruginosa (ATCC 27853) and Micrococcus flavus (ATCC 10240), were tested using the micro-dilution protocol [5,34,62,63] in microtiter plates (96-well). Serial concentrations of bark extracts were mixed with 1.0 × 10 4 colony forming unit (CFU) bacterial inoculum in each well, with 100 µL tryptic soy broth per well, then incubated for one day at 37 • C on a rotary shaker.…”

Mass Spectroscopic Analysis, MNDO Quantum Chemical Studies and Antifungal Activity of Essential and Recovered Oil Constituents of Lemon-Scented Gum against Three Common Molds

“…The second way is by the loss of a C3H7 • radical to produce [M-H2O-C3H7] + at m/z 95. The third way is by the loss of C4H9 • to produce [M-H2O-C4H9] + at m/z 81 [39]. The second fragmentation pathway of the MI of citronellol is by the simple cleavage to produce directly the FI C5H9 + with m/z 69, which represents the BP in the MS as shown in Figure 1a.…”

“…From the fragmentation pattern of citronellol (citronellal isomer) compound, it is shown that the first fragmentation pathway of the molecular ion (MI) of citronellol is the formation of the FI at m/z 138 ( Figure 2). This could be could be explained by the formation of the [ [39]. The second fragmentation pathway of the MI of citronellol is by the simple cleavage to produce directly the FI C 5 H 9 + with m/z 69, which represents the BP in the MS as shown in Figure 1a.…”