"Extraction et étude de l’activité biologique des huiles essentielles du Myrte (Myrtus communis L.)"

Abstract

Extraction of leaves and fruits Myrtus communis L. essential oils (EO), harvested from the north west region of Algeria (Zeboudja and Ténès) was performed by steam distillation and the yield was variable depending on the harvest stage (0.55-1.15% on flowering vs 0.34- 0.39% on fruiting for leaves) and the organ (0.34-0.39% for fruits). The chemical composition of EO extracted was determined by using gas chromatography (GC) and gas chromatography coupling to mass spectrometry (GC / MS). The results have revealed the existence of new chemotypes of EO myrtle leaves; that extracted from myrtle harvested at forest Bissa (Chlef) during flowering stage with major components: limonene (23.4%), linalool (15.4%), geranyl acetate (10.9%), α-pinene (10.7%), linalyl acetate (8.2%) and 1,8-cineole (6.6%) and those extracted from myrtle harvested in 14 sites in regions of Zeboudja and Ténès rich on linalool and classified into two groups (group I characterized by the dominance of α-pinene 32-49%, limonene11-30%, 1,8-cineole 10-24% and linalool 2-20%; group II dominated by linalool 20-32%, α-pinene 23-28% 1,8-cineole 16-19% and limonene 15-17%). Fruits EO were qualitatively similar to leaf EO but quantitatively different (group I: α-pinene, 21-43%, limonene 25-35%, 1,8-cineole 5-12% and linalool 1-7% ; group II : α-pinene 34-43%, 1,8-cineole 13-31%, limonene 9-13% and linalool 2-5%). EO extracted during flowering stage had a remarkable antimicrobial power. Staphylococcus aureus (Gram +) was the most sensitive (36,67mm / 8μL vs 16,67mm / 20μL noted for Escherichia coli). Also, Proteus mirabilis (ATCC 43862) was very sensitive to the presence of EO (MIC = 0.12 and MBC = 16 g / mL). MIC of 0.25-4 g / mL were noted for Proteus mirabilis (clinical), Staphylococcus aureus (ATCC 25923) and Klebsiella pneumoniae (ATCC 35657). Pseudomonas aeruginosa (ATCC 27853) was resistant to all tested doses. At the maximum dose of 0.5%, the rate of inhibition of mycelial growth was most marked for Alternaria solani (92%) followed by Fusarium oxysporum (85%), Aschocyta rabiei (64%) and Aspergillus ochraceus ( 68%). Best reducing powers of DPPH (90-91%) were noted for the myrtle harvested from the sites (Oued Gousine, Teraghnia, Dalas and Bissa). EO of samples harvested from Oued khdhar and Oued Gousine (Ténès) had the best iron reducing powers while those of myrtle harvested at Oued Gousine -Place el Khazna- and Tigharghar (Ténès) had superior iron chelating powers of the remaining samples. However, for the reducing power of ABTS test, EO samples harvested from Tifless, Oued khdhar, Teraghnia and Boucheral showed reducing activities above 50%.