Abstract:Three citrus species, Citri Reticulatae Pericarpium (CRP), lemon and kumquat, were selected as raw materials for the extraction of essential oils by supercritical CO2 extraction. Gas chromatography-mass spectrometry (GC-MS) was used to analyze the components of the samples, and the microbiostatic activities of the three essential oils against Staphylococcus aureus and Aspergillus fumigatus were also studied. The results showed that lemon essential oil had relatively high levels of alcohols (3.41%), aldehydes (2.55%), ketones (2.03%), esters (7.17%) and terpenes (34.06%), whereas the content of D-limonene (46.52%) was the lowest among the three essential oils. CRP essential oil had relatively high levels of terpenes (86.34%) and phenolic compounds (1.82%), while kumquat essential oil had relatively high levels of acid compounds (12.71%) and D-limonene (72.69%). The microbiostatic activities of these essential oils against Staphylococcus aureus and Aspergillus fumigatus were ranked as follows: lemon essential oil>CRP essential oil>kumquat essential oil. D-limonene was not the only microbiostatic component in the three essential oils, and their microbiostatic activities were closely related to microbiostatic components other than D-limonene. Other microbiostatic components, including γ-pinene and β-pinene, which were abundant in lemon essential oil, can work synergistically with D-limonene to effectively improve its microbiostatic activity. Essential oils extracted by this method can help to facilitate the development of related natural microbiostatic products.
