二氧化碳膨胀乙醇提取香樟精油的工艺研究

本研究尝试采用一种新型的绿色溶剂二氧化碳膨胀乙醇(CO2-Expanded Ethanol, CXE)从香樟叶中提取精油,并在精油的化学组成,抗氧化活性和抑菌活性方面,与常规的水蒸气蒸馏(HD)、有机溶剂提取(OSE)以及超临界二氧化碳提取(SFE)进行综合对比研究。结果表明,CXE提取油的得率为1.35%,高于超临界二氧化碳提取油的1.14%。气相色谱-质谱(GC-MS)联用分析结果显示,CXE提取油中含氧单萜类化合物较少,而倍半萜烯类化合物高于其他三种方法提取油,含量为2.49%。抗氧化活性试验结果表明,CXE提取油对DPPH自由基的清除率为82.42%,对ABTS自由基的清除能力为85.88%,活性均高于其它三种方法提取油。通过微量稀释法测定了精油抑菌活性,CXE提取油对白色念珠菌的MIC值为39 μg/mL,对黑曲霉的MIC值为19.5 μg/mL,表明CXE提取油对真菌呈现较高的抑制活性。综上所述,CXE提取过程隔氧、低温,可开发成为一种提取高品质植物精油的新方法,具有一定的应用前景。

Extraction of the essential oil from Cinnamomum camphora leaves by CO2-expanded ethanol

A novel green solvent, CO2-Expanded Ethanol (CXE), was employed to extract essential oil from Cinnamomum camphora leaves in this paper. The comprehensive evaluations of new method were made by systematically comparing with the conventional methods including hydrodistillation (HD), organic solvent extraction (OSE) and supercritical carbon dioxide extraction (SFE). First of all, the yield of the CXE oil was up to 1.35%, higher than 1.14% of SFE oil. The chemical compositions from GC-MS analysis showed the content of oxygenated monoterpenoids in CXE oil was much lower, especially the sesquiterpene hydrocarbons of the CXE oil account for up to 2.49%, higher than oils from other methods. The DPPH radical scavenging rate and ABTS radical scavenging rate of CXE oil were 82.42% and 85.88%, respectively, presenting a significantly highest activity in contrast to other samples. Additionally, the CXE oil exhibited a prominent ability against two fungi, with the minimum inhibitory concentrations (MIC) for Candida albicans and Aspergillus niger being 312.5 g/mL and 19.5 g/mL, respectively. In conclusion, the CXE extraction could be performed under relatively low-temperature and oxygen-free conditions, so that it is hopeful to be developed as a promising alternative for the extraction of bioactive components from plant materials.