Three main tools are used to determine the structures of organic molecules. These tools are infrared (IR) spectroscopy, mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy. Organic molecules absorb light (infrared, ultraviolet, etc.) at particular wavelengths based on different vibrational modes unique to the specific functional groups and structural features. In the present study, the volatile compounds of Lemon (Citrus limon L.) collected from Collo, Skikda city (Algeria), were detected and identified by Fourier Transformed Infrared Spectroscopy (FTIR) analysis (qualitative identification). FTIR allowed us to identify 10 volatile compounds and indicated than the functional groups of the essential oils are C-H (Alkene), C-H (aromatic) and C=C. The obtained results have shown that the essential oils can be fully utilized for pharmacy, cosmetology and industry.

Three main tools are used to determine the structures of organic molecules. These tools are infrared (IR) spectroscopy, mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy. Infrared Spectroscopy (IR), Mass Spectrometry (MS) and Nuclear Magnetic Resonance Spectroscopy (NMR). Organic molecules absorb light (infrared, ultraviolet, etc.) at particular wavelengths based on different vibrational modes unique to the specific functional groups and structural features. In the present study, the volatile compounds of Cinnamon (Cinnamomum zeylanicum) were detected and identified by Fourier Transformed Infrared Spectroscopy (FTIR) analysis. FTIR allowed us to identify 10 volatile compounds and indicated than the functional groups of the essential oils are CHx, C=C and C=O.

As part of the development of Algerian natural products, mainly of plant origin, we are interested in the study of the essential oil of Ruta chalepensis L. collected from Souk ahras (North-east of Algeria) obtained by hydro-distillation. Characterization of these species was made by determining yield and chemical composition. The essential oil yield of the dried plant obtained was 0.65 % (v/w). The identification of the chemical composition of the essential oil from aerial parts was carried out thanks to gas chromatography analysis coupled to mass spectrometry (GC/MS). Twenty compounds, representing for 97.25 % of the essential oil, were identified. The major constituents were 2-Dodecanone (40.15 %), 2-Nonanone (24.20 %) and 1-Nonene (15.10 %). Antimicrobial activity was tested against four pathogenic bacteria; Staphylococcus aureus (ATCC 29737), Bacillus subtilis (MTCC 5981), Escherichia coli (ATCC 25922) and Pseudomonas aeruginosa (ATCC 33988). The obtained results indicate possible applications for Ruta chalepensis L. in the treatment of various infectious and noninfectious diseases.

Medicinal plants are potential sources of natural compounds with biological activities and therefore attract the attention of researchers worldwide. Citrus oils are a complex mixture of more than a hundred components of differing chemical natures. Qualitative and quantitative analysis by gas chromatography coupled with mass spectrometry (GCMS) of the Citrus reticulata essential oil collected from El Hadaïk, Skikda City (Algeria), identified 28 compounds representing a total of 99.41%. The essential oil is constituted mainly of: D-Limonene (85.10%), Sabinene (2.49%), Linalyl acetate (2.00%), Copaene (1.80%) et α-Pinene (1.75%) totaling approximately 93.14%. The essential oil was also analyzed by Fourier transform infrared spectroscopy analysis (FTIR). FTIR spectroscopy allowed us to identify 10 volatile compounds and indicated that the functional groups of the essential oils are C-H (Alkene), C-H (aromatic) and C=C. The obtained results have shown that the essential oil can be fully utilized for pharmacy, cosmetology and industry.

Objective: This study aimed to identify the chemical composition and the antibacterial properties of essential oil from origanum vulgare growing wild in Algeria. Methods: The antibiotic activity of the essential oil was assessed on 05 strains of Bacillus (B. amyloliquefaciens FZB42, B. amyloliquefaciens S499, B. subtilis ATCC 21332, B. licheniformis ATCC 14580, B. pumilus), using the method of diffusion in a solid medium. MIC was determined by the method of integration in an agar medium. Results: The essential oil extracted from the aerial part of Origanum vulgare harvested in Azzaba located at Skikda city (North-east of Algeria) gave a yield of 2.50 %. Its analysis by CG/SM allowed the identification of 25 components, principally phenols and terpenes. The main constituents are p-Cymene (24.01 %), Thyme (23.49 %) and Carvacrol (21.31 %). The five strains showed high sensitivity towards the essential oil with inhibition diameters ranging from 21.5 mm to 41 mm and a MIC of 0.4 mg/ml. Conclusion: The essential oil of Origanum vulgare proved to be endowed with bactericidal properties against Bacillus strains.