Chemical composition and bioactivity of the volatile oil from leaves and stems of Eucalyptus cinerea

Abstract

Context: Eucalyptus cinerea F. Muell. ex Benth. (Myrtaceae) is a medium-sized tree cultivated in Egypt.

Objective: First, to determine the chemical composition of the volatile oil of the juvenile leaves and stems of E. cinerea to identify its chemotype. Second, to study the in vivo antioxidant activity and in vitro antimicrobial activity of the studied volatile oils against selected Gram-positive, Gram-negative bacteria, yeast, and mycelia fungi.

Materials and methods: The volatile oil was prepared by hydrodistillation and then identified by GC/MS analysis. Broth microdilution and agar dilution methods were applied for determining the MIC. The antioxidant activity was studied by determination of glutathione level in blood of alloxan-induced diabetic rats.

Results: The yield of the volatile oil hydrodistilled from the juvenile leaves and stems of E. cinerea was 4.5 and 0.5%, respectively. 1,8-Cineole was the major identified oxygenated monoterpenoid (84.55% and 60.15% in the juvenile leaves and stems, respectively). The antibacterial activity of the oil of the juvenile leaves was more potent against all the tested organisms than that of the stems. The (MIC) of volatile oil of the juvenile leaves against Escherichia coli, Pseudomonas aeruginosa, Streptococcus faecalis, Candida albicans, and Aspergillus flavus were 5.2, 5.6, 4, 4.8, and 12.8 μg/ml, respectively. Also, the juvenile leaves’ oil was more active as an antioxidant than that of the stems. They restored glutathione level by 33.7 ± 1.1 and 29.6 ± 0.7 mg/dl, respectively, compared with vitamin E (35.9 ± 1.2 mg/dl) which was used as a reference.

Discussion and conclusion: Results suggest that the volatile oil is 1,8-cineole chemotype. Moreover, the oil of the juvenile leaves of E. cinerea might find usefulness as a therapeutic agent following further development.

• 1
• 8-Cineole
• antimicrobial
• antioxidant
• chemotype
• Eucalyptus cinerea
• F. Muell. ex Benth.
• GC/MS
• glutathione
• MIC
• Myrtaceae