Study On Improvement Of Extraction Technology And Antibacterial Effect Of Camphor Leaf Essential Oil

The roots,stems and leaves of Cinnamomum camphora are rich in essential oil.Essential oil has many effects such as antibacterial,antioxidant,insecticidal and anti-inflammatory.However,the oil yield in the extraction of essential oil from branches and leaves is generally low.In this paper,the improvement of the extraction process of essential oil from Cinnamomum camphora leaves and the study of antibacterial effect promote the reuse of waste resources of Cinnamomum camphora leaves and improve the economic benefits of Cinnamomum camphora.The effects of solid-liquid ratio,distillation time and NaCl concentration on the oil yield and pure dew yield of camphor leaf essential oil were determined by single factor test.The optimum extraction conditions of the two distillation methods were determined by response surface test.The essential oils extracted by the two distillation methods were analyzed by gas chromatography-mass spectrometry(GC-MS).The antibacterial effect of the essential oil and the by-product pure dew in the extraction process on Pseudomonas aeruginosa,Escherichia coli,Staphylococcus epidermidis and Staphylococcus aureus was studied by the method of inhibition zone diameter determination and 96-well plate method.The results showed that:(1)The oil yield of water distillation is higher than that of water distillation.The response surface optimization test showed that the optimum process of water distillation was solid-liquid ratio 1:10.00 g/mL,distillation time 95 min,NaCl concentration 3%,and the oil yield of camphor essential oil was 1.34%.The optimum process of water distillation was solid-liquid ratio 1:12.00 g/mL,distillation time 110 min,NaCl concentration 1%,and the oil yield of camphor essential oil was 0.76%.Under the experimental conditions,the influence degree of the oil yield efficiency of the two methods is distillation time>NaCl concentration>solid-liquid ratio.(2)The essential oil components extracted by water distillation were 29 less than those by water distillation,but the relative content of main components was more.A total of 24 compounds were detected in the essential oil of Cinnamomum camphora extracted by distillation in water.There were 6 substances with relative content of more than 5%of the total substance content,which were 29.53%of dipentene dioxide,5.30%of 3-octyne-2-ol,8.26%of 9-trans-tetradecenyl acetate,3-butene-2-ol,6.20%of 2-methyl-4 and 5.08%of palmitic acid.A total of 53 compounds were detected in the essential oil of Cinnamomum camphora extracted by water distillation.There were 6 kinds of substances with relative content of more than 5%of the total substance content,including linalool(7.17%),trans-nerolidol(13.85%),(-)-caryophyllene oxide(9.09%),naphthol AS-phosphate,free naphthol(7.96%),eucalyptol(9.15%),2,4-dimethyl-2,6-octadiene(6.74%).There are three common compounds in the essential oil of camphor extracted by water and water distillation,which are camphor,3-decyne-2-ol and dipentene dioxide.(3)The antibacterial effect of camphor essential oil extracted by water distillation is better than that by water distillation.The essential oil of camphor extracted by distillation in water has bacteriostatic effect on all three strains.The inhibition zone diameters of Staphylococcus epidermidis and Escherichia coli were 17.9 mm and 18.7 mm,respectively,which were highly sensitive.The MIC values were 3.125 μg/mL and the MBC values were 6.250 μg/mL.The inhibition zone diameter of Staphylococcus aureus was 15.4 mm,which was highly sensitive.The MIC value was 6.250 μg/mL and the MBC value was 12.50 μg/mL.However,it had no antibacterial effect on Pseudomonas aeruginosa.The essential oil of camphor extracted by water distillation performed well in the antibacterial test of the two strains.Among them,the diameter of the inhibition zone for Staphylococcus epidermidis reached 15.5 mm,which was highly sensitive;for Staphylococcus aureus,the inhibition zone diameter was 11.2 mm,which was moderately sensitive.The MIC value was 3.125 μg/mL,and the MBC value was 6.250 μg/mL.The MIC value was 12.50 μg/mL,and the MBC value was 50.00 μg/mL.However,it had no bacteriostatic effect on Escherichia coli and Pseudomonas aeruginosa.The results showed that the by-product of the two extraction methods,camphor pure dew,had no bacteriostatic effect on Pseudomonas aeruginosa,Escherichia coli,Staphylococcus aureus and Staphylococcus epidermidis.Based on a series of studies on camphor essential oil,this paper provides technical reference and scientific theoretical basis for the industrial production and further rational utilization of camphor essential oil by using the optimal process conditions of oil extraction and antibacterial effect.