Preparation process of melaleuca leucadendron essential oil

Abstract

The invention provides a preparation process of melaleuca leucas essential oil. The preparation process comprises the following steps: picking melaleuca leucas leaves, cleaning, shredding, carrying out ultrasonic treatment, carrying out molecular force gradient separation and carrying out component analysis. The molecular force gradient separation is that volatile compounds in the cajeput virens are sequentially separated for 2-100 gradients according to the molecular force from weak to strong by utilizing the molecular force intensity difference of essential oil compounds, and the essential oil of each gradient is obtained. According to the method, efficient separation of chemical components of the melaleuca leucas essential oil is achieved, and the biological activity of the essential oil can be improved and the components irritating to the skin or the tissue can be removed by enriching bioactive components and components irritating to the skin or the tissue. The essential oil with different chemical components and contents can be prepared according to actual requirements.

Description

Technical Field

[0001] The invention relates to the technical field of natural product extraction, and in particular to a preparation process of Niaouliu essential oil. Background Art

[0002] Melaleuca alternifolia ( Melaleuca viridiflora Sol. ex Gaertn. is a typical species of the genus Melaleuca, also known as five-veined melaleuca, broad-leaved melaleuca, and green tea tree. It is native to Australia and Asia and has been introduced and cultivated in China in provinces such as Hainan, Guangdong, and Yunnan. Niaouli essential oil contains a large number of monoterpenes and sesquiterpenes, which exhibit excellent antimicrobial activity. However, its strong irritation to skin and tissues limits its application. The enrichment and separation of the different chemical components of Niaouli essential oil has become a bottleneck for its industrialization. However, the relatively low polarity and molecular weight of the essential oil components make their separation difficult. Although molecular distillation can be used to separate essential oil components by exploiting differences in their molecular mean free paths, many chemical components with similar molecular mean free paths remain difficult to separate effectively. Furthermore, the systematic separation of essential oil components using molecular distillation is complex. Therefore, the systematic separation, purification, and preparation of essential oils containing the target components remain challenging. Summary of the Invention

[0003] The purpose of the present invention is to solve the problems existing in the above-mentioned prior art and to provide a preparation process for Niaouliu essential oil. The process can cause molecular force differences based on the differences in hydrogen bonds, ionic bonds, van der Waals forces, dipole-dipole interactions, functional groups, molecular weight, molecular surface area, and molecular symmetry of the compound molecules in the essential oil, and adopts molecular force ladder separation technology to separate the compounds in the volatile oil, enrich the active ingredients, and remove the irritating ingredients. In other words, by utilizing the characteristic that the strength of the molecular force of the compound is inversely proportional to the volatility, the compound molecules are volatilized in sequence from weak to strong at different temperature ladders (≤100°C), and the chemical components are collected separately according to the temperature ladder, thereby achieving the purpose of compound separation, active ingredient enrichment, and irritating ingredient enrichment, and obtaining different essential oils with enriched chemical components, which is conducive to removing chemical components that are irritating to the skin or tissue, and different Niaouliu essential oils are applied to different fields according to the characteristics of their chemical components.

[0004] In order to achieve the above object, the technical solution of the present invention is: to provide a preparation process of Niaouliu essential oil, which is prepared by the following steps.

[0005] S1. Pick the pure green and shiny Melaleuca alternifolia leaves.

[0006] S2, clean and dry the leaves of Melaleuca viridiflora, cut into shreds, the width of the shreds is 0.1-10 mm, and the length is 1-100 mm.

[0007] Preferably, the width of the shreds is 1-2 mm.

[0008] Preferably, the length of the shreds is 30-60 mm.

[0009] S3, mix the cut shreds of Melaleuca viridiflora leaves with distilled water, and then ultrasonically treat the mixture in a closed container, the mass ratio of the shreds to the distilled water is 1:1-1:10, the ultrasonic power is 200-2000 W, the ultrasonic time is 10-60 min, and the ultrasonic temperature is 30-90℃.

[0010] Preferably, the mass ratio of the shreds to the distilled water is 1:1-1:3.

[0011] Preferably, the ultrasonic power is 500-1000 W.

[0012] Preferably, the ultrasonic time is 20-40 min.

[0013] Preferably, the ultrasonic temperature is 50-80℃.

[0014] S4, place the mixture of the ultrasonically treated Melaleuca viridiflora leaves and distilled water in an essential oil extraction device, and vacuumize the upper end of a condenser tube of the essential oil extraction device, so that essential oils are extracted from the condenser tube in 2-100 temperature steps in an arithmetic sequence, and essential oils with different chemical components and contents are obtained.

[0015] Preferably, the number of the temperature steps in the arithmetic sequence is 10-20.

[0016] S5, essential oil chemical component analysis Various essential oils are analyzed by GC-MS, and compared with essential oils extracted by traditional steam distillation method, and the enrichment of chemical components of various essential oils is analyzed. The GC-MS conditions are as follows: in terms of gas chromatography conditions, HP-5MS (30 m × 250 μm, 0.25 μm) chromatographic column, the sample is diluted by 100-1000 times of chromatographic grade n-hexane, the injection port temperature is 250℃, the carrier gas (He) flow rate is 1.0 mL·min -1 , the injection amount is 1 μL, the septum purge is 3 mL·min -1 , the split ratio is 2:1, and the split flow is 2 mL·min -1 . In terms of temperature programming, the initial column temperature is 60℃, which is gradually increased to 220℃ at a rate of 8℃·min -1 , and then maintained for 2 min, and then increased to 10 ℃·min -1 .The run was performed from 220°C to 280°C and held for 10 minutes, for a total run time of 38 minutes. Mass spectrometry conditions included a 3-minute solvent delay, a quadrupole temperature of 150°C, a mass spectrometer ionization voltage of 70 eV, an AUX-2 temperature of 250°C, an EI ion source temperature of 230°C, and a mass scan range of m / z 50-1050. The comparison database was the NIST17 mass spectrometry data.

[0017] Preferably, the chromatography-grade n-hexane is diluted 400-600 times.

[0018] The beneficial effects of the present invention compared to the prior art are: 1. The present invention provides a preparation process for Niaouliu essential oil, which can classify the compounds in the essential oil according to the strength of the molecular forces of the compounds, thereby achieving the purpose of effectively separating and enriching the compounds and obtaining essential oils with different chemical components and their contents.

[0019] 2. By separating and enriching the compounds, the biologically active compounds can be enriched together, thereby improving the biological activity of the essential oil.

[0020] 3. By separating and enriching the compounds, the compounds that are irritating to the skin or tissues can also be enriched together, thereby reducing the side effects of other separated essential oils and expanding the application areas of essential oils.

[0021] 4. The present invention can prepare essential oils containing target compounds according to actual needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the fingerprint similarity between the essential oils of each level.

[0023] Figure 2 This is a superimposed comparison chart of the fingerprint maps of each level of Niaouliu essential oil.

[0024] Figure 3 This is an Upset diagram of the differences in the essential oil compounds of each level of Niaouliu.

[0025] Figure 4 The main chemical component categories and percentages of Niaouliu essential oils of each grade. DETAILED DESCRIPTION

[0026] The present invention is described in detail below with reference to the accompanying drawings and embodiments. It is apparent that the embodiments described are only a portion of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, other embodiments obtained by those of ordinary skill in the art without creative effort are also within the scope of protection of the present invention. Example 1:

[0027] The application discloses a preparation process of Melaleuca alternifolia essential oil.

[0028] S1, picking green pure and shiny Melaleuca alternifolia leaves.

[0029] S2, cleaning the Melaleuca alternifolia leaves, drying the leaves, cutting the leaves into strips, the width of the leaf strips being 1-2 mm, and the length of the leaf strips being 30-60 mm.

[0030] S3, mixing the cut leaf strips with distilled water, and carrying out ultrasonic treatment in a closed container, the mass ratio of the leaf strips to the distilled water being 1:2, the ultrasonic power being 720 W, the ultrasonic time being 25 min, and the ultrasonic temperature being 69 DEG C.

[0031] S4, placing the mixture of the ultrasonic treated leaf strips and the distilled water in an essential oil extraction device, and vacuumizing the upper end of a condenser tube of the essential oil extraction device, so that the extraction liquid boils at 40 DEG C plus or minus 1 DEG C, and the essential oil is obtained after 4 h of extraction, and the essential oil is named as MEO-40; then the pressure in the extraction device is adjusted to continue the extraction, so that the extraction liquid boils at 45 DEG C plus or minus 1 DEG C, and the essential oil is obtained after 4 h of extraction, and the essential oil is named as MEO-45; the extraction is continued at a gradient of 5 DEG C to obtain 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 and 100 DEG C essential oils, which are named as MEO-50, MEO-55, MEO-60, MEO-65, MEO-70, MEO-75, MEO-80, MEO-85, MEO-90, MEO-95 and MEO-100 respectively; and 13 kinds of Melaleuca alternifolia essential oils are obtained; in addition, the essential oil extracted by a traditional water vapor distillation method is named as MEO-Tr.

[0032] S5, the yield is measured as follows: the yield of MEO-40, MEO-45, MEO-50, MEO-55, MEO-60, MEO-65, MEO-70, MEO-75, MEO-80, MEO-85, MEO-90, MEO-95 and MEO-100 is 0.01%, 0.01%, 0.03%, 0.03%, 0.07%, 0.05%, 0.12%, 0.08%, 0.07%, 0.03%, 0.04%, 0.04% and 0.05% respectively.

[0033] S6, GC-MS was used to analyze the 13 kinds of essential oils separated above and compare them with essential oils extracted by traditional steam distillation method to analyze the separation and enrichment of the chemical components of various essential oils. The GC-MS conditions are as follows: in terms of gas chromatography conditions, HP-5MS (30 m x 250 μm, 0.25 μm) chromatographic column, the sample was diluted 500 times with chromatographic grade n-hexane, the injection port temperature was 250℃, the carrier gas (He) flow rate was 1.0 mL·min -1 , the injection volume was 1 μL, the septum purge was 3 mL·min -1 , the split ratio was 2:1, and the split flow was 2 mL·min -1 . In terms of temperature programming, the initial column temperature was 60℃, which was gradually increased to 220℃ at a rate of 8 ℃·min -1 , then maintained for 2 min, and then increased from 220℃ to 280℃ at a rate of 10 ℃·min -1 , maintained for 10 min, and the total running time was 38 min. In terms of mass spectrometry conditions, the solvent delay was 3 min, the quadrupole rod temperature was 150℃, the mass spectrometry ionization voltage was 70 eV, the AUX-2 temperature was 250℃, the EI ion source temperature was 230℃, and the mass scan range was m / z 50-1050. The comparison database was NIST17 mass spectrometry data.

[0034] S7, data analysis (1) Traditional Chinese medicine fingerprint similarity analysis To verify the separation effect of molecular force gradient separation technology on essential oils, the similarity of the fingerprint of each essential oil sample was analyzed. The closer the similarity value is to 1, the higher the similarity of the two chromatograms. The similarity of the essential oil fingerprint (Similarity, referred to as S) is shown in Figure 1 , and the similarity of each gradient separation essential oil is significantly different, among which the similarity of MEO-40 and MEO-100 is the lowest (S=0.430), and the similarity of MEO-45 and MEO-50 is the highest (S=0.999). The similarity between other essential oils is between 0.430-0.999, and the similarity of adjacent gradient separation essential oils is smaller. From the similarity trend analysis, the larger the temperature gradient during essential oil separation, the lower the similarity of essential oil components, and vice versa, indicating that the chemical components and their contents of essential oil components are different in different gradients, proving that it is feasible to separate essential oil components in different gradients by molecular force gradient separation technology in this experiment.

[0035] From Figure 2The retention time and abundance of the compounds in each essential oil can be seen intuitively, and the difference in retention time reflects the difference in compound types. The chemical components of the essential oil separated at 40-75℃ are relatively concentrated, and the retention time of the compounds is concentrated in the three intervals of 5.5-6 min, 7.5-9 min, and 14.5-15 min, and the relative content in the interval of 5.5-6 min is the highest; the retention time of the chemical components of the essential oil separated at 80-90℃ and traditional steam distillation is concentrated in the four intervals of 4-5 min, 5.5-6 min, 7.5-9 min, and 14.5-15 min; the retention time of the chemical components of the essential oil separated at 90-100℃ is concentrated in the three intervals of 4-5 min, 5.5-6 min, and 14.5-15 min. Figure 2 It can also be seen that compound retention times and abundances change with separation temperature, demonstrating the feasibility of utilizing the different molecular forces of essential oil chemical components to separate them in a cascade from low to high concentrations. This demonstrates that the molecular force cascade separation technique used in this experiment can effectively separate the components of Niaouliu essential oil.

[0036] (2) Chemical composition of Niaouliu essential oil Through the separation and identification of the essential oil components, a total of 43 compounds were extracted and identified, namely (1R)-(+)-α-pinene, benzaldehyde, β-pinene, myrcene, pseudolimonene, α-terpinene, 1,8-cineole, γ-terpinene, isoterpinene, linalool, fenchol, trans-1-methyl-4-(1-methylvinyl)cyclohex-2-en-1-ol, cis-2,8-menthadien-1-ol, (-)-trans-pine carveol, neoisotarexol, (1R,2S,5R)-endo-5-methyl-2-(1-methylvinyl)cyclohexanol, 2-camphenol, terpinen-4-ol, (+)-α-terpineol, citronellol, 3-allyl-6-methoxyphenol, isolongifolene, α-guruene, caryophyllene, 1H-Cycloprop[e] azulene,1a,2,3,4,6,7,7a,7b-octahydro-1,1,4,7-tetramethyl-, (1Z,4Z,7Z)-1,5,9,9-tetramethyl-1,4,7-cycloundecatriene, galanthus, γ-serinene, β-serinene, chlorophyllene, γ-cadinene, δ-cadinene, (+)-γ-gulurinene, epiglobol, 1,1,4,7-tetramethyl-2,3,4,5,6,7,7a,7b-octahydro-1aH-cyclopropyl[h]benzopentacyclic-4a-ol, caryophyllene oxide, chlorophyllene, trumpet alcohol, γ-eudesyl alcohol, 2-isopropyl-5-methyl-9-methylvinylidenebicyclo[4.4.0]dec-1-ene, α-eudesyl alcohol, (+)-trullene, longifolia aldehyde. Among them, MEO-40, MEO-50, MEO-55, MEO-60, MEO-65, MEO-70, MEO-75, MEO-80, MEO-85, MEO-90, MEO-95, and MEO-100 identified 20, 22, 23, 24, 25, 19, 23, 24, 29, 26, 31, 30, and 31 compounds, respectively. Traditional steam distillation yielded 28 compounds. The molecular force ladder separation technique, used to enrich and separate essential oil components, identified 15 more compounds than traditional steam distillation. Furthermore, the chemical components enriched in the 13 separated essential oils varied significantly, achieving the goal of enriching and separating the chemical components of essential oils.

[0037] Figure 3As shown in the Upset plot, a total of 43 compounds were identified across the 13 separated essential oils and those extracted by traditional steam distillation, 14 of which were shared. In the high-temperature separation, MEO-95 and MEO-100 had the most shared compounds, with 30 shared compounds; MEO-90 and MEO-100 had 29 shared compounds; and MEO-90, MEO-95, and MEO-100 had 28 shared compounds. The high-temperature separation yielded a high number of shared compounds, indicating that the separation of these oils using the high-temperature separation was less than ideal. In the low-temperature separation, MEO-40, MEO-45, and MEO-50 shared 19 shared compounds; MEO-65 shared 17 shared compounds with MEO-45 and MEO-50; and MEO-65 shared 19 shared compounds with MEO-70, indicating that the low-temperature separation yielded better results. Comparison between the low-temperature and high-temperature echelons revealed that MEO-65 had only 15 common compounds with MEO-90, MEO-95, and MEO-100 of the high-temperature echelon; MEO-45 and MEO-50 of the low-temperature echelon had only 16 common compounds with MEO-90, MEO-95, and MEO-100 of the high-temperature echelon; and MEO-55, MEO-60, and MEO-70 of the low-temperature echelon had only 18 common compounds with MEO-90, MEO-95, and MEO-100 of the high-temperature echelon. This indicates that the essential oil compositions of the low-temperature echelon are quite different from those of the high-temperature echelon, proving that it is feasible to separate the essential oil components in this experiment by using the molecular force size of the chemical components of the essential oils.

[0038] (3) Analysis of the main chemical components of Melaleuca alternifolia essential oil Figure 4The chemical composition of Melaleuca alternifolia essential oils is primarily composed of terpenes, including monoterpenes, monoterpenoids, sesquiterpenes, and sesquiterpenoids. The percentage of terpenes in all 14 essential oils was no less than 97.29%. MEO-45, MEO-60, MEO-65, and MEO-70 were all terpenoids, while the terpenoid contents of MEO-40, MEO-50, MEO-55, MEO-75, MEO-80, MEO-85, MEO-90, MEO-95, MEO-100, and MEO-Tr were 98.40%, 98.96%, 98.71%, 99.24%, 99.94%, 98.95%, 97.29%, 97.56%, 98.50%, and 99.80%, respectively. Although the percentages of terpenes in all essential oils were high, the percentages of different terpenes varied significantly. MEO-40, MEO-45, MEO-50, MEO-55, MEO-60, MEO-65, MEO-70, MEO-75, MEO-80 and MEO-Tr. are mainly composed of monoterpene alcohol compounds, with the percentage contents being 86.69%, 86.79%, 84.03%, 81.33%, 79.07%, 81.92%, 73.91%, 59.85%, 41.99% and 50.24%, respectively; however, MEO-85, MEO-90, MEO-95 and MEO-100 are mainly composed of sesquiterpene alcohol compounds, with the percentage contents being 32.6%, 33.99%, 37.21% and 39.13%, respectively. It can be seen that the chemical components of Melaleuca alternifolia essential oil are mainly monoterpene alcohols and sesquiterpene alcohols. The percentages of MEO-40, MEO-45, MEO-50, MEO-55, MEO-60, MEO-65, MEO-70, MEO-75, MEO-80, MEO-85, MEO-90, MEO-95, MEO-100 and MEO-Tr. alcohols are 95.76%, 97.49%, 94.52%, 93.91%, 92.93%, 88.84%, 88.33%, 80.04%, 68.11%, 63.77%, 56.76%, 55.60%, 53.54% and 75.78% respectively. Moreover, among the 13 essential oils separated, the percentage of alcohols shows an overall downward trend with the increase of separation temperature. In addition, Figure 4 It can also be seen intuitively that as the separation temperature increases, the monoterpene alcohol content of the 13 separated essential oils shows an overall decreasing trend, while the percentage content of monoterpenes, sesquiterpenes and sesquiterpene alcohols shows an increasing trend.

[0039] In summary, low temperature is conducive to the separation and enrichment of monoterpenoids, while high temperature is conducive to the separation and enrichment of monoterpenes, sesquiterpenes and sesquiterpenoids. This method has a significant effect on the separation of terpenoids in Melaleuca alternifolia essential oil, and its regularity is relatively strong. Example 2

[0040] A preparation process of a Melaleuca alternifolia essential oil, characterized in that the Melaleuca alternifolia essential oil contains a higher monoterpenol compound, and the preparation process comprises the following steps.

[0041] S1, picking Melaleuca alternifolia leaves with green color and good luster.

[0042] S2, washing the Melaleuca alternifolia leaves clean and drying the water, cutting the leaves into silk, the width of the leaf silk is 1-2 mm, and the length is 30-60 mm.

[0043] S3, mixing the cut Melaleuca alternifolia leaves with distilled water, and then ultrasonic treating in a closed container, the mass ratio of the material to the liquid is 1:2, the ultrasonic power is 720 W, the ultrasonic time is 25 min, and the ultrasonic temperature is 69℃.

[0044] S4, placing the mixture of the ultrasonic treated Melaleuca alternifolia leaf silk and distilled water in a round bottom flask of an essential oil extraction device, and vacuumizing from the upper end of a condenser tube of the essential oil extraction device, so that the extraction liquid is boiled at 40±1℃, and after 4 h of extraction, the essential oil is obtained.

[0045] S5, measuring the yield of 0.01%.

[0046] S6, analyzing the essential oil composition by GC-MS, and the GC-MS conditions are as follows: in terms of the gas chromatography conditions, the HP-5MS (30 m × 250 μm, 0.25 μm) chromatographic column, the sample is diluted 500 times with chromatographic grade n-hexane, the injection port temperature is 250℃, the carrier gas (He) flow rate is 1.0 mL·min -1 , the injection amount is 1 μL, the septum purge is 3 mL·min -1 , the split ratio is 2:1, and the split flow is 2 mL·min -1 . In terms of the temperature rising program, the initial column temperature is 60℃, which is gradually increased to 220℃ at a rate of 8 ℃·min -1 , and then kept for 2 min, and then increased to 280℃ at a rate of 10 ℃·min -1 , kept for 10 min, and the total running time is 38 min. In terms of the mass spectrometry conditions, the solvent delay is 3 min, the quadrupole rod temperature is 150℃, the mass spectrometry ionization voltage is 70 eV, the AUX-2 temperature is 250℃, the EI ion source temperature is 230℃, and the mass scan range is m / z 50-1050. The comparison database is NIST17 mass spectrometry data.

[0047] S7, data analysis A total of 20 compounds were identified from the essential oil, including (1R)-(+)-α-pinene, β-pinene, 1,8-cineole, γ-terpinene, terpinene, linalool, fenchol, neoisopalamol, (1R,2S,5R)-endo-5-methyl-2-(1-methylvinyl)cyclohexanol, 2-camphenol, terpinen-4-ol, (+)-α-terpineol, citronellol, caryophyllene, 1,1,4,7-tetramethyl-2,3,4,5,6,7,7a,7b-octahydro-1aH-cyclopropyl[h]benzopentacyclo-4a-ol, caryophyllene oxide, chlorophyllinol, terpinol, 2-isopropyl-5-methyl-9-methylvinylidenebicyclo[4.4.0]dec-1-ene, and α-cineole. The monoterpene content was 1.35%, the monoterpene alcohol content was 86.69%, the sesquiterpene content was 1.29%, the sesquiterpene alcohol content was 9.07%, and the content of other compounds was 1.60%. This method clearly favors the enrichment of monoterpene alcohols, with the extracted essential oil containing the highest monoterpene alcohol content, reaching 86.69%. However, it is not conducive to the enrichment of monoterpenes, with the monoterpene content being only 1.35%. Monoterpene alcohols possess antibacterial, anti-inflammatory, and antioxidant activities and are used in natural medicines and health supplements, whereas monoterpenes often cause allergies and skin irritation. Therefore, the essential oil extracted by this method has stronger biological activity and fewer side effects such as skin irritation.

[0048] Example 3: A preparation process of Niaouliu essential oil, characterized in that the Niaouliu essential oil contains a relatively high content of sesquiterpenoid compounds, and the preparation process comprises the following steps.

[0049] S1. Pick the pure green and shiny Melaleuca alternifolia leaves.

[0050] S2. Clean the Melaleuca alternifolia leaves, dry them in the air, and cut them into shreds with a width of 1-2 mm and a length of 30-60 mm.

[0051] S3. Mix the shredded Melaleuca alternifolia leaves with distilled water and perform ultrasonic treatment in a closed container with a material-liquid ratio of 1:2 by mass, an ultrasonic power of 720 W, an ultrasonic time of 25 min, and an ultrasonic temperature of 69°C.

[0052] S4. Place the mixture of ultrasonically treated Melaleuca alternifolia leaf shreds and distilled water in a round-bottom flask of an essential oil extraction device, and evacuate the upper end of the condenser of the essential oil extraction device to boil the extract at 40±1°C. After extraction for 4 hours, take the essential oil and discard it. Continue to extract the essential oils at 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 and 100°C in increments of 5°C. Only collect the 100°C essential oil and discard the other essential oils.

[0053] S5, measurement yield 0.05%.

[0054] S6. GC-MS was used to analyze the essential oil components. The GC-MS conditions were as follows: For gas chromatography, an HP-5MS (30 m × 250 μm, 0.25 μm) column was used, the sample was diluted 500 times with chromatographic grade n-hexane, the inlet temperature was 250°C, and the carrier gas (He) flow rate was 1.0 mL∙min -1 , injection volume 1 μL, septum purge 3 mL∙min -1 , split ratio 2:1, split flow rate 2 mL∙min -1 In terms of temperature program, the initial column temperature was 60℃, and the temperature was increased at 8℃∙min -1 Gradually increase the temperature from 60℃ to 220℃, maintain for 2 min, and then increase the temperature at 10℃∙min -1 The run was performed from 220°C to 280°C and held for 10 minutes, for a total run time of 38 minutes. Mass spectrometry conditions included a 3-minute solvent delay, a quadrupole temperature of 150°C, a mass spectrometer ionization voltage of 70 eV, an AUX-2 temperature of 250°C, an EI ion source temperature of 230°C, and a mass scan range of m / z 50-1050. The comparison database was the NIST17 mass spectrometry data.

[0055] S7. Data Analysis A total of 31 compounds were identified from the essential oil, including (1R)-(+)-α-pinene, benzaldehyde, β-pinene, pseudolimonene, α-terpinene, 1,8-cineole, γ-terpinene, terpinene, fenchol, 2-terpineol, terpinen-4-ol, (+)-α-terpineol, citronellol, isolongifolene, caryophyllene, 1H-Cycloprop[e] azulene,1a,2,3,4,6,7,7a,7b-octahydro-1,1,4,7-tetramethyl-, (1Z,4Z,7Z)-1,5,9,9-tetramethyl-1,4,7-cycloundecatriene, eugenol, γ-serinene, β-serinene, chlorophyllene, γ-cadinene, δ-cadinene, 1,1,4,7-tetramethyl-2,3,4,5,6,7,7a,7b-octahydro-1aH-cyclopropyl[h]benzopentacyclic-4a-ol, caryophyllene oxide, chlorophyllene, trumpet alcohol, 2-isopropyl-5-methyl-9-methylvinylidenebicyclo[4.4.0]dec-1-ene, α-eudesmol, (+)-trumpene, longifolia aldehyde. Among them, the monoterpene content is 21.43%, the monoterpene alcohol content is 14.41%, the sesquiterpene content is 23.53%, the sesquiterpene alcohol content is 39.13%, and the content of other compounds is 1.50%. It can be seen that this method is conducive to the enrichment of sesquiterpene alcohol compounds. The extracted essential oil has the highest sesquiterpene alcohol content, reaching 39.13%, especially enriched with chlorophyllin, whose content is 21.61%. Sesquiterpene alcohol compounds are widely used in the spice industry and can be used to formulate various flavors. Chlorophyll is also commonly used in medical research and has potential pharmacological research value. Therefore, the essential oil extracted by this method can be used in the field of spices and pharmacological research.

[0056] In summary, Example 1 can classify and segment the components of Niaouliu essential oil, and Examples 2 and 3 can separate essential oils with higher target compounds according to actual needs.

[0057] The above disclosure is merely a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope of the present invention.

Claims

1. A preparation process of Niaouliu essential oil, characterized in that, The preparation process of the Niaouliu essential oil is prepared by the following steps: S1. Pick pure green and shiny Melaleuca alternifolia leaves; S2. Wash the Melaleuca alternifolia leaves, dry them, and cut them into shreds with a width of 0.1-10 mm and a length of 1-100 mm. S3. Mix the shredded Melaleuca alternifolia leaves with distilled water, and then perform ultrasonic treatment in a sealed container, with a material-liquid ratio of 1:1-1:10 by mass, an ultrasonic power of 200-2000 W, an ultrasonic time of 10-60 min, and an ultrasonic temperature of 30-90°C; S4, placing the mixture of the ultrasonically treated Niaouliu leaves and distilled water in an essential oil extraction device, and evacuating the upper end of the condenser tube of the essential oil extraction device to extract the essential oil in sequence at 2-100 arithmetic increasing temperature steps to obtain essential oils with different chemical compositions and contents thereof; S5. Analysis of chemical components of essential oils GC-MS was used to analyze the chemical composition of the separated essential oils and compared them with those extracted by traditional steam distillation. The GC-MS conditions were as follows: HP-5MS (30 m × 250 μm, 0.25 μm) column, sample dilution 100-1000 times with chromatographic grade n-hexane, injection temperature 250°C, carrier gas (He) flow rate 1.0 mL∙min -1 , injection volume 1 μL, septum purge 3 mL∙min -1 , split ratio 2:1, split flow rate 2 mL∙min -1 ; In terms of heating program, the initial column temperature was 60℃, and the temperature was increased at 8℃∙min -1 The temperature was gradually increased from 60°C to 220°C and held for 2 min, then increased from 220°C to 280°C at a rate of 10°C∙min-1 and held for 10 min. The total running time was 38 min. In terms of mass spectrometry conditions, the solvent delay was 3 min, the quadrupole temperature was 150°C, the mass spectrometry ionization voltage was 70 eV, the AUX-2 temperature was 250°C, the EI ion source temperature was 230°C, and the mass scan range was m / z 50-1050. The comparison database was the NIST17 mass spectrometry data.

2. The preparation process of the Niaouliu essential oil according to claim 1, wherein: The width of the leaf thread is 1-2 mm, and the length of the leaf thread is 30-60 mm.

3. The preparation process of the Niaouliu essential oil according to claim 1, wherein: The mass ratio of the material to the liquid is 1:1-1:3, the ultrasonic power is 500-1000 W, the ultrasonic time is 20-40 min, and the ultrasonic temperature is 50-80° C.

4. The preparation process of Niaouliu essential oil as claimed in claim 1, wherein: The number of the arithmetic difference increasing temperature steps is 10-20.

5. The preparation process of Niaouliu essential oil as claimed in claim 1, wherein: The chromatography grade n-hexane was diluted 400-600 times.

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