Study On The Extraction Process, Chemical Composition, In Vitro Antioxidant And Antibacterial Activity Of The Essential Oil Of Platycladus Orientalis

In order to obtain the best extraction process, the essential oil of Platycladus orientalis was extracted by supercritical fluid extraction and steam distillation extraction, the chemical compositions were analyzed and compared; the antioxidant and antibacterial activities was tested. The results were shown below.1. The orthogonal test was used to screen for the best extraction process of supercritical fluid extraction in extracting the essential oils of Platycladus orientalis. The essential oils were extracted by CO2 supercritical fluid extraction, under 15 MPa, the dynamic extraction times was 4 h, the rate of flow was 500 L/h, the temperature was 45℃, the static extraction time was 0 h, extraction yield was 4.59%. And the extraction yield was 1.02% when the essential oils were extracted by steam distillation extraction. Compared of the extraction yield, aroma, energy dissipation, benefit and color of essential oil form Platycladus orientalis by supercritical fluid extraction and steam distillation extraction, the SFE was better than SDE.2. Chemical composition of the essential oil of Platycladus orientalis by supercritical fluid extraction and steam distillation extraction determined by gas chromatography coupled to mass spectrometry (GC-MS). Forty-five and thirty-seven compounds were determined in the essential oil of Platycladus orientalis extracted by supercritical CO2 extraction and the essential oil of Platycladus orientalis extracted by steam distillation extraction. The major compounds identified in the oil by supercritical fluid extraction were Cedrol (36.41%), Thujopsen (17.09%), Cedrene (9.21%) and Curcumene (7.13%) whereas essential oil by steam distillation extraction were Cedrol (11.13%), Longifolene (6.5%), Thujopsen (31.31%) and Cedrene (23.7%). Fourteen compounds are same and fifty-four compounds are difference.3. Cedrol was isolated and purified by atmospheric distillation, solvent extraction and recrystallization from the essential oil of Platycladus orientalis, the Cedrol was 96.65%. Under the temperature of 4℃,70% ethanol was the optimal recrystallization solvent.4 The antioxidant activities showed that the essential oil of Platycladus orientalis extracted by supercritical CO2 extraction had good ability in scavenging potential DPPH radicals (EC50< 0.02 mg/mL), hydroxyl radicals (1.2 mg/mL< EC50<1.6 mg/mL) and inhibition of peanut oil peroxide. And the essential oil of Platycladus orientalis extracted by steam distillation extraction had ordinary ability in scavenging potential DPPH radicals (EC50> 2.4 mg/mL), hydroxyl radicals (EC50> 2.4 mg/mL) and inhibition of peanut oil peroxide.5. Filter paper method was used to screen for the microorganism which was more sensitive to the essential oil of Platycladus orientalis. Escherichia coli, Xanthomonas Campestris, Staphylococcus aureus and Bacillus subtilis were screened, Aspergillus Niger and Saccharomycete cerevisiae were eliminate. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were tested by the gradient dilution method. The MIC of the essential oil of Platycladus orientalis was 0.03,0.51,7.69 and 2.47 mg/mL by SFE, The MBC was 0.09,1.86,89.42 and 36.51 mg/mL. The MIC of the essential oil of Platycladus orientalis was 0.88,3.44,15.33 and 9.45 mg/mL by SDE, The MBC was 9.17,33.63,143.07 and 76.42 mg/mL.