Essential oil components of orange peels and antimicrobial activity

In this study, the orange peel of 12 cultivars of Citrus sinensis from central-eastern Sicily was employed to obtain essential oils and extracts. The ones were extracted through steam distillation, the others through extraction in hexane. Chemical constituents were evaluated in terms of qualitative and quantitative analyses by gas chromatography/mass spectrometry. Fifty-four components were identified in the steam essential oils and 44 in the extracts. In all the cultivars, the main component is d-limonene (73.9-97%); discrete percentages of linalool, geraniol and nerol were also found. Cluster analysis based on essential oils composition showed a certain degree of affinity between cultivars of the same type. The antimicrobial activity was investigated against three micro-organisms (Staphylococcus aureus, Listeria monocytogens and Pseudomonas aeruginosa). 'Sanguinello' and 'Solarino Moro' essential oils are significantly active against L. monocytogenes, while 'Valencia' hexanic extract against all the tested micro-organisms.