Comparative Study on the Essential Oils Extracted from Tunisian Rosemary and Myrtle: Chemical Profiles, Quality, and Antimicrobial Activities

Abstract

Rosemary (Rosmarinus officinalis L.) and myrtle (Myrtus communis L.) are perennial herbs, typical of the Tunisian flora, with an intense aromatic flavor. Their essential oils, obtained by hydro-distillation, were analyzed by gas chromatography coupled to mass spectrometry and by infrared Fourier transform spectrometry. In addition, these oils were assessed for their physicochemical properties as well as their antioxidant and antibacterial activities. The physicochemical characterization proved to be of good quality by analyzing pH, water content (%), density at 15 °C (g/cm 3 ), and iodine values according to standard test methods. The study of the chemical composition allowed for the identification of 1,8-cineole (30%) and α-pinene (40.4%) as the main constituents of myrtle essential oil, while 1,8-cineole (37%), camphor (12.5%), and α-pinene (11.6%) were identified as principal components in rosemary essential oil. The evaluation of their antioxidant activities permitted to obtain the IC 50 values, which ranged between 22.3 and 44.7 μg/mL for DPPH and between 15.52 and 28.59 μg/mL for ferrous chelating assay, for rosemary and myrtle essential oils, respectively, thus indicating that rosemary essential oil is the most effective antioxidant. Furthermore, the antibacterial activity of the essential oils was tested in vitro against eight bacterial strains by the disc diffusion method. The essential oils showed antibacterial effects on both Gram-positive and Gramnegative bacteria.

Improvement of Microbial Quality, Physicochemical Properties, Fatty Acids Profile, and Shelf Life of Basa (Pangasius bocourti) Fillets during Chilling Storage Using Pepsin, Rosemary Oil, and Citric Acid

“…Besides the aforementioned compounds, there were several compounds detected with a considerable level, such as α-terpineol (5.61%), camphene (4.89), p-cymene (3.28), D-limonene (2.59), bornyl acetate (1.67%), and terpinen-4-ol (1.41%) (Table 3). Our findings are comparable with those of Diniz-Silva et al [37] and Dhouibi et al [38], who found that the most abundant compounds in rosemary EOs were eucalyptol, camphor, and α-pinene. In the same regard, the most predominant compounds in rosemary EOs originating from Russia and Serbia were α-pinene, eucalyptol, and camphor [39].…”

Rosmarinus officinalis Essential Oil Increases Hair Length and Follicle Diameter of Ultraviolet B-exposed Mice Through VEGF

“…(20) The IC 50 value of ROEO in the present study was lower than those in the previous studies, which was about 20-22 ppm. (21)(22)(23) Antioxidant activity of ROEO can be primarily attributed to the presence of phenolics, including flavonoids and tannins (15,24), as shown by the results of TPC, TFC, and TTC analyses. Phenolics counteract lipid peroxidation and reactive oxygen species (ROS) by stabilizing free electrons released by the oxidants through conversion to ketones.…”

Rosemary: Unrevealing an old aromatic crop as a new source of promising functional food additive—A review

“…The main bioactive components, monoterpenes, sesquiterpenes, terpenes (isoprene), and aliphatic and aromatic compounds (aldehydes and phenols), of REOs are characterized by low molecular weight and high biocompatibility with potent antimicrobial activity. The antibacterial activity of the main components of REO may be related to its bacteriostatic effect, and the lipophilic components can easily diffuse on the bacterial cell membrane to inhibit tested bacteria (Dhouibi, Flamini et al, 2023;Silva et al, 2019). Ojeda-Sana et al (2013) suggested that α-pinene had a broad antibacterial spectrum with excellent inhibition toward S. aureus, Enterococcus faecalis, and Klebsiella pneumoniae with MIC ranging from 0.8 to 8.0 µL/mL, while 1,8-cineole showed considerable antibacterial activity against pathogenic bacteria by causing cell membrane rupture.…”

“…The main bioactive components, monoterpenes, sesquiterpenes, terpenes (isoprene), and aliphatic and aromatic compounds (aldehydes and phenols), of REOs are characterized by low molecular weight and high biocompatibility with potent antimicrobial activity. The antibacterial activity of the main components of REO may be related to its bacteriostatic effect, and the lipophilic components can easily diffuse on the bacterial cell membrane to inhibit tested bacteria (Dhouibi, Flamini et al., 2023; Silva et al., 2019). Ojeda‐Sana et al.…”