Method for separating flavokawain and kavalactone, kavalactone, and microencapsulated kavalactone

Abstract

The present application relates to a technical field of separating kavalactone and flavokawain, and in particular, to a method for separating flavokawain and kavalactone, kavalactone, and microencapsulated kavalactone. The separation method includes: S1. grinding root of piper methysticum, extracting by supercritical carbon dioxide and collecting a residue for later use, in which an extraction temperature is 45-50 C. and an extraction pressure is 4-8 MPa; S2. extracting the residue by supercritical carbon dioxide, and collecting extracted oil for later use, in which an extraction temperature is 60-80 C. and an extraction pressure is 20-50 MPa; S3. performing re-extraction and adsorption on the extracted oil to obtain a primary product of the kavalactone; and S4. crystallizing the primary product of kavalactone to obtain the kavalactone. The obtained kavalactone is used for microencapsulated kavalactone.

Claims

1. A method for separating flavokawain and kavalactone, comprising the steps of: step S1: grinding root of piper methysticum, extracting by supercritical carbon dioxide and collecting a residue, wherein an extraction temperature during the step S1 is 45-50 C. and an extraction pressure during the step S1 is 4-8 MPa; step S2: extracting the residue by the supercritical carbon dioxide, and collecting extracted oil, wherein an extraction temperature during the step S2 is 60-80 C. and an extraction pressure during the step S2 is 20-50 MPa; step S3: performing re-extraction and an adsorption treatment on the extracted oil to obtain a primary product of the kavalactone; and step S4: crystallizing the primary product of the kavalactone to obtain the kavalactone; wherein the kavalactone is a mixture of six compounds, comprising: Methysticin, Dihydromethystcin, Kavain, Dihydrokavain, Yangonin and Desmethoxyangonin; wherein the re-extraction in the step S3 comprises the steps of: dissolving the extracted oil in a first solvent; and performing the re-extraction by using a re-extraction solvent to obtain an extraction mother solution, wherein the first solvent is 80-95 vol. % of an ethanol solution or 80-95 vol. % of a methanol solution, and the re-extraction solvent is one or more of N-hexane, petroleum ether, or ether; wherein the adsorption treatment in the step S3 uses an adsorbent, and the adsorbent is one or more selected from a group consisting of silicone, alumina, activated carbon, C18, polyamide, and Sephadex LH-20.

2. The method according to claim 1, wherein, in the step S1, an extraction time is 60-180 min, and a flow rate of the supercritical carbon dioxide is 10-50 mL/min; and, in step S2, an extraction time is 120-180 min, and a flow rate of the supercritical carbon dioxide is 60-100 mL/min.

3. The method according to claim 1, wherein an adsorption temperature in the step S3 is 50-90 C.

4. The method according to claim 1, wherein the adsorbent is a mixture of the C18, the silicone and the activated carbon in a weight ratio of (0.8-1.5):(4.5-5.8):(3-4).

5. The method according to claim 1, wherein the crystallizing in the step S4 comprises the following steps: dissolving the primary product of the kavalactone in a second solvent, heating, then adding a third solvent, stirring until a crystal appears, and standing for solid-fluid separation to obtain a kavalactone crystal.

6. The method according to claim 5, wherein a heating temperature in the step S4 is 40-80 C., the second solvent is one or more selected from a group consisting of methyl acetate, methyl butanone, methanol, ethanol, acetone, and ethyl acetate, and the third solvent is one or more selected from a group consisting of the petroleum ether, the N-hexane, and dichloromethane.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a liquid chromatogram of flavokawain in a kavalactone crystal obtained by separation method of Example 2;

(2) FIG. 2 is a liquid chromatogram of kavalactone in a kavalactone crystal obtained by separation method of Example 2.

DETAILED DESCRIPTION

(3) The present application was further described in detail below in combination with FIGS. 1-2.

(4) Examples of a Method for Separating Flavokawain and Kavalactone

Example 1 of the Separation Method

(5) A method for separating flavokawain and kavalactone included the following specific steps: S1. the root of piper methysticum was ground, 1 kg of powder of the piper methysticum root was weighed and added into a supercritical extraction kettle, then 50 C. of temperature and 8 MPa of pressure were set, supercritical CO.sub.2 was added at a flow rate of 10 mL/min to perform extraction for 60 min. Then extracted oil and residue were collected. The yield of the extracted oil was 1.8% by weight, that is, the obtained extracted oil was 18 g. In the extracted oil, a total amount of flavokawain A and flavokawain B was 8.51 wt %, that is, 1.53 g. In the extracted oil, the content of kavalactone was 1.02 wt %, i.e. 0.18 g. S2. the residue obtained in the step S1 was put into the supercritical extraction kettle again, then another extraction was performed at 60 C. of temperature, 20 MPa of pressure, and a supercritical CO.sub.2 flow rate of 60 mL/min. The extraction was stopped after 180 min, then the residue was removed, and extracted oil was collected for later use. The yield of the extracted oil was 12.4 wt %, that is, the obtained extracted oil was 124 g. The content of kavalactone in the extracted oil was 75.43 wt %, i.e. 94 g. The content of flavokawain (flavokawain A and the flavokawain B) in the extracted oil was 2.02 wt %, i.e. 2.50 g. S3. The extracted oil obtained in the step S2 was re-extracted and adsorbed. Specific steps were as follow: The extracted oil was dissolved in 80 Vol. % of methanol solution having a volume twice that of the extracted oil, and then n-hexane with equal volume of 80 Vol. % of methanol solution was added for re-extracting. The solution was sufficiently mixed under shaking, and left to stand, achieving a further separation of kavalactone and flavokawain (flavokawain A and the flavokawain B). The collected alcohol phase was used as an extraction mother solution, and the extraction mother solution was concentrated into an oil-like solution, which weighed 120 g, for later use. The concentrated extraction mother solution was dissolved in 80 Vol. % of methanol solution, heated up to 50 C., added with 1.2 g of adsorbent, left for absorption under stirring for 4 h, and then filtered to obtain a filtrate, and the obtained filtrate was concentrated into a paste, which weighed 90 g, for later use. The adsorbent was SephadexLH-20, that is, Sephadex LH. S4. The paste obtained in the step S3 was dissolved in ethyl acetate having an addition amount of 0.5 times the weight of the paste, that is, 45 g. The solution was heated, added with petroleum ether slowly, and stirred at a rotary speed of 25 rpm, in which, volume ratio of ethyl acetate and petroleum ether was 8.5:1.8. When there was crystal appearing, the stirring was stopped, and the solution was left to stand for crystallization for 12 h, thereby obtaining kavalactone crystal.

Example 2 of the Separation Method

(6) A method for separating flavokawain and kavalactone included the following specific steps: S1. the root of piper methysticum was ground, 1 kg of powders of the piper methysticum root was weighed and added into a supercritical extraction kettle, and then 48 C. of temperature and 6 MPa of pressure were set, supercritical CO.sub.2 was added at a flow rate of 30 mL/min to perform extraction for 120 min. Then extracted oil and residue were collected. The yield of the extracted oil was 2% by weight, that is, the obtained extracted oil was 20 g. In the extracted oil, the total amount of flavokawain A and flavokawain B was 10.04 wt %, that is, 2 g. In the extracted oil, the content of kavalactone was 1.5 wt %, i.e. 0.3 g. About 50% of flavokawain (flavokawain A and the flavokawain B) were removed by the step. S2. the residue obtained in the step S1 was put into the supercritical extraction kettle again, then another extraction was performed at 70 C. of temperature and 35 MPa of pressure, and a supercritical CO.sub.2 flow rate of 80 mL/min. The extraction was stopped after 150 min, then the residue was removed, and extracted oil was collected for later use. The yield of the extracted oil was 13 wt %, that is, the obtained extracted oil was 130 g. The content of kavalactone in the extracted oil was 85.62 wt %, i.e. 111.3 g. The content of flavokawain (flavokawain A and the flavokawain B) in the extracted oil was 2.53 wt %, i.e. 3.3 g. S3. The extracted oil obtained in step S2 was re-extracted and adsorbed. Specific steps were as follow: the extracted oil was dissolved in a 90 Vol. % of ethanol having a volume 3.5 times that of the extracted oil, and then n-hexane with equal volume of 90 Vol. % of ethanol solution was added to for re-extracting. The solution was sufficiently mixed under shaking, and was left to stand, achieving a further separation of kavalactone and flavokawain (flavokawain A and the flavokawain B). The collected alcohol phase was used as an extraction mother solution, and the extraction mother solution was concentrated into oil-like solution, which weighed 125 g, for later use. The concentrated extraction mother solution was dissolved in 90 Vol. % of ethanol solution, heated up to 70 C., added with 4.6 g of adsorbent, left for adsorption under stirring for 5 h, and then filtered to obtain a filtrate, and the filtrate was concentrated into paste, which weighed 98 g, for later use. The adsorbent was a mixture of C18, silicone and activated carbon in a weight ratio of 1.2:5.3:3.5. S4. The paste obtained by the step S3 was dissolved in methanol having an addition amount of 98 g. The solution was heated, added with dichloromethane slowly, and stirred at a rotary speed of 25 rpm, in which, volume ratio of methanol and dichloromethane was 9.2:1.8. When there was crystal appearing, stirring was stopped, and the solution was left to stand for crystallization for 20 h, thereby obtaining kavalactone crystal. Liquid chromatograms of flavokawain and kavalactone in the kavalactone crystal were shown in FIG. 1 and FIG. 2, respectively.

Example 3 of the Separation Method

(7) A method for separating flavokawain and kavalactone included the following steps: S1. the root of piper methysticum was ground, 1 kg of powder of the piper methysticum root were weighed and added into a supercritical extraction kettle, and then 45 C. of temperature and 4 MPa of pressure were set, supercritical CO.sub.2 was added at a flow rate of 50 mL/min to perform extraction for 180 min. Then extracted oil and residue was collected. The yield of the extracted oil was 2.5% by weight, that is, the obtained extracted oil was 25 g. In the extracted oil, the total amount of flavokawain A and flavokawain B was 13.07 wt %, that is, 3.27 g. In the extracted oil, the content of kavalactone was 2.07 wt %, i.e. 0.5 g. S2. the residue obtained in the step S1 was put into the supercritical extraction kettle again, another extraction was performed at 80 C. of temperature and 50 MPa of pressure, and a supercritical CO.sub.2 flow rate of 100 mL/min. The extraction was stopped after 120 min, then the residue was removed, and extracted oil was collected for later use. The yield of the extracted oil was 11 wt %, that is, the obtained extracted oil was 110 g. The content of kavalactone in the extracted oil was 88.16 wt %, i.e. 97.0 g. The content of flavokawain (flavokawain A and the flavokawain B) in the extracted oil was 3.07 wt %, i.e. 3.4 g. S3. The extracted oil obtained by the step S2 was re-extracted and adsorbed. Specific steps were as follow: the extracted oil was dissolved in a 95 Vol. % of ethanol having a volume 5 times the volume of the extracted oil, and then n-hexane with equal volume of 95 Vol. % of ethanol solution was added to for re-extracting. The solution was sufficiently mixed under shaking, and was left to stand, achieving a further separation of kavalactone and flavokawain (flavokawain A and the flavokawain B). The collected alcohol phase was used as an extraction mother solution, and the extraction mother solution was concentrated into oil-like solution, which weighed 122 g, for later use. The concentrated extraction mother solution was dissolved in 95 Vol. % of ethanol solution, heated up to 90 C., added with 6.7 g of adsorbent, left for adsorption under stirring for 8 h, and then filtered to obtain a filtrate, and the filtrate was concentrated into paste which weighed 103 g, for later use. The adsorbent was a mixture of silicone and activated carbon in a weight ratio of 5.3:3.5. S4. The paste obtained by the step S3 was dissolved in acetone having an addition amount of acetone 2 times weight of the paste, that is, 206 g. The solution was heated, added with n-hexane slowly, and stirred at a rotary speed of 25 rpm, in which, volume ratio of acetone and n-hexane was 10:1.8. When there was crystal appearing, stirring was stopped, and the solution was left to stand for crystallization for 24 h, thereby obtaining kavalactone crystal.

Examples 4-11 of the Separation Method

(8) The following examples differed from Example 2 in that process temperatures or process pressures were different in the supercritical extraction kettle of the steps S1 or S2, as shown in Table 1.

(9) TABLE-US-00001 TABLE 1 process temperatures and pressures in the S1 and S2 of different examples step S1 step S2 Process Process Process Process Process pressure/ temperature/ pressure/ temperature/ parameter MPa C. MPa C. Example 6 48 35 70 2 Example 4 48 35 70 4 Example 8 48 35 70 5 Example 6 45 35 70 6 Example 6 50 35 70 7 Example 6 48 20 70 8 Example 6 48 50 70 9 Example 6 48 35 60 10 Example 6 48 35 80 11

Example 12 of the Separation Method

(10) The present example differs from Example 2 in that the adsorbent used in the step S3 was different. Specifically, the adsorbent used in the present example was a mixture of C18, silicone and activated carbon in a weight ratio of 0.8:4.5:3. Other conditions were the same as those in Example 2.

Example 13 of the Separation Method

(11) The present example differs from Example 2 in that the adsorbent used in the step S3 was different. Specifically, the adsorbent used in the present example was a mixture of C18, silicone and activated carbon in a weight ratio of 1.5:5.8:4. Other conditions were the same as those in Example 2.

Comparative Examples 1-8 of the Separation Method

(12) The following comparative examples differed from Example 2 in that the process time or flow rate of supercritical CO.sub.2 were different in the supercritical extraction kettle of the step S1 or S2 as shown in Table 2.

(13) TABLE-US-00002 TABLE 2 process time and flow rate of supercritical CO.sub.2 in the S1 and S2 of different examples step S1 step S2 Process Flow rate of Process Flow rate of Process time/ supercritical CO.sub.2/ time/ supercritical CO.sub.2/ parameter min (mL/min) min (mL/min ) Example 2 120 30 150 80 Comparative 40 30 150 80 Example 1 Comparative 200 30 150 80 Example 2 Comparative 120 5 150 80 Example 3 Comparative 120 55 150 80 Example 4 Comparative 120 30 100 80 Example 5 Comparative 120 30 200 80 Example 6 Comparative 120 30 150 40 Example 7 Comparative 120 30 150 120 Example 8

Comparative Examples 1-7 of the Separation Method

(14) The following comparative examples differed Example 2 in that the process temperatures or pressures were different in the supercritical extraction kettle of the steps S1 or S2, as shown in Table 3.

(15) TABLE-US-00003 TABLE 3 process temperatures and pressures in the S1 and S2 of different comparative examples step S1 step S2 Process Process Process Process Process pressure/ temperature/ pressure/ temperature/ parameters MPa C. MPa C. Example 2 6 48 35 70 Comparative 2 48 35 70 Example 1 Comparative 12 48 35 70 Example 2 Comparative 6 40 35 70 Example 3 Comparative 6 55 35 70 Example 4 Comparative 6 48 15 70 Example 5 Comparative 6 48 35 55 Example 6 Comparative 6 48 35 85 Example 7

Comparative Example 8 of the Separation Method

(16) The present comparative example differed from Example 2 in that the step S1 was removed from the separation method, and the separation method was as follows: S1. the root of piper methysticum was ground, 1 kg of powders of the piper methysticum root were weighed and added into a supercritical extraction kettle, and then 70 C. of temperature and 35 MPa of pressure were set, supercritical CO.sub.2 was added at a flow rate of 80 mL/min and extracted for 150 min. Then residue was removed, and extracted oil was collected for later use. S2. Specific steps were same as those in step S3 of Example 2. S3. Specific steps were same as those in step S4 of Example 2, by which kavalactone crystal was obtained. The content of kavalactone in the kavalactone crystal was 93.64 wt %, and total amount of flavokawain A and the flavokawain B was 1.21 wt %.

Comparative Example 9 of the Separation Method

(17) The present comparative example differed from Example 2 in that, merely a re-extraction process was included in the step S3 of the separation method, and the separation method were as follow: S1 and S2 were same as the S1 and the S2 of Example 2, and 130 g of extracted oil was obtained. S3. extracted oil obtained in the step S2 was re-extracted.

(18) Specific steps were as follow: the extracted oil was dissolved in a 90 Vol. % of ethanol having a volume 3.5 times the volume of the extracted oil, and then petroleum ether with equal volume of 90 Vol. % of ethanol solution was added for re-extracting. The solution was sufficiently mixed under shaking, and was left to stand, achieving a further separation of kavalactone and flavokawain (flavokawain A and the flavokawain B). The collected alcohol phase was extraction mother solution, the extraction mother solution was concentrated into oil-like solution, which weighed 125 g, for later use.

(19) S4. The extraction mother solution concentrated into oil-like solution obtained in the step S3 was dissolved in 125 g of methanol, and treated by the same subsequent steps as those in Example 2, thereby obtaining the kavalactone crystal.

Comparative Example 10 of the Separation Method

(20) The comparative example differed from Example 2 in that, merely an adsorption process was performed in the step S3 of the separation method, and the separation method was as follows: S1 and S2 were same as the S1 and the S2 of Example 2, and 130 g of extracted oil was obtained. S3. The extracted oil obtained in the step S2 was adsorbed. Specific steps were as follow: the extracted oil was dissolved in 90 Vol. % of ethanol solution; and the dissolved solution was heated up to 70 C., added with 4.6 g of adsorbent, and left for adsorption under stirring for 5 h, and then filtered to obtain a filtrate, and the filtrate was concentrated into paste for later use. The adsorbent was a mixture of C18, silicone and activated carbon in a weight ratio of 1.2:5.3:3.5. S4 was same as the S4 of Example 2.

Comparative Example 11 of the Separation Method

(21) The present comparative example differed from Example 2 in that adsorption process was firstly performed and re-extraction process was secondly performed. The separation method was as follows:

(22) S1 and S2 were same as the S1 and the S2 of Example 2, and 130 g of extracted oil was obtained.

(23) S3. The extracted oil obtained by the step S2 was adsorbed. Specific steps were as follow: The extracted oil was dissolved in a 90 Vol. % of ethanol having a volume 3.5 times the volume of the extracted oil, and the dissolved solution was heated up to 70 C., added with 4.6 g of adsorbent, left for adsorption under stirring for 5 h, and then filtered to obtain a filtrate, and the filtrate was concentrated into paste for later use. The adsorbent was a mixture of C18, silicone and activated carbon in a weight ratio of 1.2:5.3:3.5.

(24) The concentrated into paste-like filtrate was dissolved in 90 Vol. % of ethanol having a volume 3.5 times the volume of the paste-like filtrate; and then petroleum ether with equal volume of 90 Vol. % ethanol solution was added for re-extracting. The solution was sufficiently mixed under shaking, and was left to stand, achieving a further separation of kavalactone and flavokawain (flavokawain A and the flavokawain B). The collected alcohol phase was used as extraction mother solution, and the extraction mother solution was concentrated into oil-like solution for later use.

(25) S4. The oil-like concentrated extraction mother solution was dissolved in methanol, and then treated by the same subsequent steps as those in Example 2, thereby obtaining kavalactone crystal.

(26) Performance Tests Experiments

(27) The detection of contents of kavalactone and flavokawain A and the flavokawain B were public in the literature of Piper methysticum Rootstock Dry Extract on the Herbal Medicines Compendium; and the contents were tested by using a high-performance Liquid Chromatographic. Results were shown in Table 4.

(28) TABLE-US-00004 TABLE 4 the content of kavalactone and flavokawain in the products obtained from each stage in different examples Exam- Exam- Exam- Exam- Exam- Exam- Exam- Embodiment ple 1 ple 2 ple 3 ple 4 ple 5 ple 6 ple 7 After Yield of 1.8 2.0 2.5 1.8 2.5 1.8 2.1 being extracted treated oil % by step Content of 8.51 10.04 13.07 8.92 12.63 8.97 12.53 S1 kavalactone in the extracted oil % Contents of A 1.02 1.54 2.07 1.36 1.92 1.31 2.06 and B in the extracted oil % After Yield of 12.4 13.0 11.0 12.9 13.0 13.1 12.9 being extracted treated oil %% by step Content of 75.43 85.62 88.16 85.33 85.21 85.29 85.47 S2 kavalactone in the extracted oil % Contents of A 2.02 2.53 3.07 3.04 2.35 3.17 2.51 and B in the extracted oil % Kavalactone Content of 98.12 99.02 98.51 98.68 99.22 98.56 99.12 crystal kavalactone/ % Contents of A 0.05 0.05 0.07 0.07 0.05 0.08 0.04 and B % the content of kavalactone and flavokawain in the products obtained from each stage in different examples Comparative Exam- Exam- Exam- Exam- Exam- Exam- Exam- Embodiment ple 8 ple 9 ple 10 ple 11 ple 12 ple 13 ple 1 After Yield of 2.0 2.1 2.0 1.9 2.0 2.1 1.4 being extracted treated oil % by step Content of 10.05 10.03 10.05 10.02 10.01 10.04 8.63 S1 kavalactone in the extracted oil % Contents of A 1.51 1.54 1.52 1.54 1.53 1.51 1.31 and B in the extracted oil % After Yield of 11.5 13.3 11.2 13.7 13.0 13.0 12.8 being extracted treated oil % by step Content of 85.03 86.21 84.82 87.12 85.67 85.21 85.56 S2 kavalactone in the extracted oil % Contents of A 2.42 2.69 2.54 2.93 2.49 2.52 3.32 and B in the extracted oil % Kavalactone Content of 99.39 99.11 99.54 99.06 99.23 99.41 98.31 crysta kavalactone/ % Contents of A 0.05 0.08 0.05 0.06 0.06 0.03 0.15 and B % the content of kavalactone and flavokawain in the products obtained from each stage in different examples Com- Com- Com- Com- par- par- par- par- ative ative ative ative Comparative Comparative Comparative Exam- Exam- Exam- Exam- Exam- Exam- Exam- Embodiment ple 2 ple 3 ple 4 ple 5 ple 6 ple 7 ple 8 After Yield of 2.8 1.2 2.7 2.0 2.1 1.9 2.0 being extracted treated oil % by step Content of 14.92 8.54 14.53 10.02 10.06 10.01 10.05 S1 kavalactone in the extracted oil % Contents of A 1.97 1.16 1.92 1.52 1.54 1.50 1.53 and B in the extracted oil % After Yield of 13.0 12.9 13.1 10.5 13.7 10.2 13.8 being extracted treated oil % by step Content of 85.43 85.52 85.56 84.01 82.25 83.24 86.94 S2 kavalactone in the extracted oil % Contents of A 2.73 3.36 2.81 2.48 2.42 3.12 2.81 and B in the extracted oil % Kavalactone Content of 98.63 98.42 98.02 98.02 98.82 98.21 99.01 crysta kavalactone/ % Contents of A 0.12 0.16 0.14 0.09 0.15 0.18 0.15 and B % the content of kavalactone and flavokawain in the products obtained from each stage in different examples Com- Com- Com- Com- par- par- par- par- Comparative Comparative Comparative ative ative ative ative Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Embodiment ple 1 ple 2 ple 3 ple 4 ple 5 ple 6 ple 7 After Yield of 0.8 3.2 1.2 3.0 2.1 2.0 1.9 being extracted treated oil % by step Content of 5.21 20.32 7.55 18.01 10.06 10.02 10.01 S1 kavalactone in the extracted oil % Contents of A 0.52 2.51 1.04 2.64 1.52 1.51 1.49 and B in the extracted oil % After Yield of 13.1 13.2 13.0 12.9 8.6 9.3 13.8 being extracted treated oil % by step Content of 86.33 88.26 87.63 88.03 80.13 81.42 88.06 S2 kavalactone in the extracted oil % Contents of A 7.13 4.01 6.84 4.06 5.04 4.51 3.82 and B in the extracted oil % Kavalactone Content of 95.82 97.13 97.16 97.89 96.28 97.32 93.26 crysta kavalactone/ % Contents of A 1.22 0.48 1.06 0.50 1.03 0.84 0.36 and B % the content of kavalactone and flavokawain in the products obtained from each stage in different examples Com- Com- parative parative Comparative Comparative Embodiment ple 8 ple 9 Example 10 Example 11 After Yield of / 2.1 2.1 2.0 being extracted treated oil % by step Content of / 10.04 10.04 10.03 S1 kavalactone in the extracted oil % Contents of A / 1.52 1.51 1.53 and B in the extracted oil % After Yield of / 13.1 13.0 13.2 being extracted treated oil % by step Content of / 85.57 85.61 85.7 S2 kavalactone in the extracted oil % Contents of A / 2.56 2.53 2.56 and B in the extracted oil % Kavalactone Content of 93.64 98.63 98.82 98.84 crysta kavalactone % Contents of A 1.21 0.51 0.92 0.74 and B %

(29) Comparing the results of Example 2, Examples 4-5 and Comparative Examples 1-2, it can be seen that, in step S1, it is suggested that the extraction pressure should be set as 4-8 MPa in the step S1: when the extraction pressure is lower than 4 MPa (Comparative Example 1), it resulted in a poor separation efficiency of flavokawain (flavokawain A and the flavokawain B), and a large amount of flavokawain (flavokawain A and the flavokawain B) was remained in the residue, such that a large amount of flavokawain (flavokawain A and the flavokawain B) were extracted together with kavalactone in the step S2; however, flavokawain (flavokawain A and the flavokawain B) and kavalactone were not sufficiently separated by re-extraction and adsorption, therefore the content of flavokawain (flavokawain A and the flavokawain B) in the obtained kavalactone crystal was relatively high. When the pressure was higher than 8 MPa (comparative Example 2), a large amount of kavalactone and flavokawain (flavokawain A and the flavokawain B) was extracted together and discarded as waste liquid, which directly resulted in excessive loss of kavalactone; meanwhile, cells of raw materials were damaged by excessive extraction pressure in the extraction process of S1, such that containing inside the cells were more easily extracted, therefore, after re-extraction of S2 was finished, the content of flavokawain (flavokawain A and the flavokawain B) were higher in the extracted oil, and the content of other impurities were also higher. Therefore, considering from two aspects, that is, the utilization rate of kavalactone and the content of flavokawain in kavalactone crystal, extraction pressure of more than 8 MPa in the step S1 was not suggested.

(30) Comparing the results of Example 2, Examples 6-7 and Comparative Examples 3-4, it can be seen that, it is suggested that extraction temperature in the step S1 should be set as 45-50 C.: when the extraction temperature was lower than 45 C. (Comparative Example 3), it also resulted in that a large amount of flavokawain (flavokawain A and the flavokawain B) was remained in the residue, thereby a large amount of flavokawain (flavokawain A and the flavokawain B) was extracted together with kavalactone in the step S2, finally the content of flavokawain (flavokawain A and the flavokawain B) in the obtained kavalactone crystal was relatively higher; and when the temperature was higher than 50 C. (Comparative Example 4) in the step S1, it also resulted in problems such as excessive loss of kavalactone, high content of flavokawain (flavokawain A and the flavokawain B). Therefore extraction temperature of more than 50 C. in the step S1 was not suggested.

(31) Comparing the test results of Example 2, Examples 8-9 and Comparative Examples 5, it can be seen that, it is suggested that extraction pressure in the step S2 should be set as 20-50 MPa: when the extraction pressure was lower than 20 MPa (Comparative Example 5), it resulted in that a large amount of kavalactone were remained in the residue and discarded as waste material, therefore, considering from the utilization rate of kavalactone, extraction pressure of lower than 20 MPa in the step S2 was not suggested; and, under an extraction pressure of lower than 20 MPa, flavokawain (flavokawain A and the flavokawain B) was more easily extracted, which resulted in a problem of high content on flavokawain (flavokawain A and the flavokawain B) in the kavalactone crystal. In addition, considering an affordable pressure for the equipment, an extraction pressure of more than 8 MPa was not suggested.

(32) Comparing the results of Example 2, Examples 10-11 and comparative Examples 6-7, it can be seen that, it is suggested that extraction temperature should be set as 60-80 C. in the step S2: when the extraction temperature was lower than 60 C. (Comparative Example 6), it also resulted in that a large amount of kavalactone were remained in the residue and discarded as waste materials; in addition, the lower temperature was more suitable for extraction of flavokawain (flavokawain A and the flavokawain B), so that there was a poor separation efficiency of kavalactone and flavokawain (flavokawain A and the flavokawain B). Therefore, considering from two aspects, that is, the utilization rate of kavalactone and separation efficiency of kavalactone and flavokawain (flavokawain A and the flavokawain B), the temperature of lower than 60 C. is not suggested. When temperature was higher than 80 C. (comparative Example 7), other impurities except for kavalactone and flavokawain (flavokawain A and the flavokawain B) were extracted, which directly resulted in more and more impurities in the kavalactone crystal and low content of kavalactone.

(33) In the process, the influence of extraction pressure and temperature on separation efficiency is significant, meanwhile, extraction time and flow rate of supercritical CO.sub.2 are also one of parameters promising technical effects.

(34) Comparing the results of Example 2 and Comparative Examples 1-2, it can be seen that, it is suggested that, extraction time should be set in a range of 60-80 min. When the extraction time was higher than 180 min (Comparative Example 2), separation efficiency of kavalactone and flavokawain will be reduced, and the content of flavokawain (flavokawain A and the flavokawain B) in the kavalactone crystal will be increased. That's because a sufficient separation can be achieved between flavokawain (flavokawain A and the flavokawain B) and kavalactone of the residue in the step S1, however, a greater degree of damage to cells of piper methysticum in the step S1 can be caused by excessive extraction time, so the containing inside the cells were more easily extracted. After the residue was processed by the step S2, kavalactone was extracted with more flavokawain (flavokawain A and the flavokawain B) and other impurities, resulting in a relatively high content of flavokawain (flavokawain A and the flavokawain B) in the obtained kavalactone crystal.

(35) Comparing the test results of Example 2, Comparative Examples 3-4, it can be seen that flow rate of supercritical CO.sub.2 for extracting in the step S2 was recommended in the range of 10-50 mL/min. Exceeding the range will also had an impact on the separation efficiency of kavalactone and flavokawain.

(36) In addition, Comparative Examples 5-8 can be seen that separation efficiency was affected by extraction time and flow rate of supercritical CO.sub.2 in the step S2. The yield of extracted oil was affected by a short extraction time of Comparative Example 5, and the extraction of kavalactone was not sufficient, resulting in a relatively high proportion of flavokawain (flavokawain A and the flavokawain B) in the extracted oil, and a relatively high content (0.09 wt %) of flavokawain (flavokawain A and the flavokawain B) in the obtained kavalactone crystal. The extraction time was excessively long in the Comparative Example 6, other impurities were extracted with kavalactone and flavokawain (flavokawain A and the flavokawain B), therefore, the relative content of kavalactone was reduced, however, the content (0.09 wt %) of flavokawain (flavokawain A and the flavokawain B) in the obtained kavalactone crystal was higher. Likewise, flow rate of supercritical CO.sub.2 had a similar impact on separation efficiency. High content of flavokawain (flavokawain A and the flavokawain B) in the kavalactone crystal was caused by the flow rate of supercritical CO.sub.2 was lower than 60 mL/min or higher than 100 mL/min in the Comparative Example 7.

(37) However, among the four extraction parameters (temperature, pressure, time and flow rate of supercritical CO.sub.2) of S1 and S2, temperature and pressure had a relatively greater impact on separation efficiency, and time and flow rate of supercritical CO.sub.2 had a less impact on separation efficiency.

(38) However, comparing the test results of Example 2 and comparative Example 8, it can be seen that kavalactone and flavokawain (flavokawain A and the flavokawain B) were separated by using extraction method of high temperature and pressure, which is difficult to achieve the purpose of effective separation, such as there was still 1.21 wt % of flavokawain in the obtained kavalactone crystal.

(39) Further combining comparative Examples 9-11, it can be seen that re-extraction and adsorption were also important to the separation of kavalactone and flavokawain. Firstly, the separation of kavalactone and flavokawain can be achieved by using re-extraction method, secondly, the separation of kavalactone and flavokawain can be achieved by using adsorption. It was not recommended that the separation of kavalactone and flavokawain can be achieved by using first re-extraction and second adsorption in the technical solution, otherwise it is difficult to achieve separation efficiency, and the content of flavokawain in the obtained kavalactone crystal was still higher than 0.1 wt %.

Examples of the Microencapsulated Kavalactone

Example 1 of the Microencapsulated Kavalactone

(40) The microencapsulated kavalactone includes an inner core and an outer cladding layer, raw materials of the inner core were as follow: kavalactone crystal and 85 Vol. % of ethanol solution, raw materials of the outer cladding layer were as follow: excipient, film former and water. The weight ratio of excipient and kavalactone was 1:1; the excipient was a combination of emulsified starch and dextrine in a weight ratio of 1:1. Film former was xanthan gum, and the weight ratio of the film former and the excipient was 1:100. Kavalactone crystal was obtained by using the separation method of Example 1.

(41) A method for preparing the microencapsulated kavalactone was as follows: I. Preparation of oil phase: dissolving 200 g of kavalactone crystal in 85-95 Vol. % of ethanol solution, then concentrating into a grease, and storing at 75 C. for later use; preparation of water phase: dissolving 200 g of excipient into 1600 g of hot water with 80 C. for later use; II. Adding the oil phase into the water phase in the high-speed shearing with 8000 rpm of rotation rate, then adding xanthan gum, and shearing for 30 min at the high-speed, and then spray-drying at 80 C. to obtain the microencapsulated kavalactone. The microencapsulated kavalactone can be stored for 24 months at the room temperature.

Example 2 of the Microencapsulated Kavalactone

(42) The microencapsulated kavalactone includes an inner core and an outer cladding layer, raw materials of the inner core were as follow: kavalactone crystal and 90 Vol. % of ethanol solution, raw materials of the outer cladding layer were as follow: excipient, film former and water. The weight ratio of excipient and kavalactone was 22:10; the excipient was a combination of emulsified starch and dextrine in a weight ratio of 4:1. Film former was arabic gum, and the weight ratio of the film former and the excipient was 2:100. Kavalactone crystal was obtained by using the separation method of Example 2.

(43) A method for preparing the microencapsulated kavalactone was as follows: I. Preparation of oil phase: dissolving 200 g of kavalactone crystal in 90 Vol. % of ethanol solution, then concentrating into a grease, and storing at 80 C. for later use; preparation of water phase: dissolving 440 g of excipient into 3960 g of hot water with 90 C. for later use; II. Adding the oil phase into the water phase in the high-speed shearing with 10000 rpm of rotation rate, then adding 0.88 g of arabic gum, and shearing for 45 min at the high-speed, and then spray-drying at 85 C. to obtain the microencapsulated kavalactone. The microencapsulated kavalactone can be stored for 26 months at the room temperature. The content of kavalactone was 30.52 wt % in the microencapsulated kavalactone.

Example 3 of the Microencapsulated Kavalactone

(44) The microencapsulated kavalactone includes an inner core and an outer cladding layer, raw materials of the inner core were as follow: kavalactone crystal and 95 Vol. % of ethanol solution, raw materials of the outer cladding layer were as follow: excipient, film former and water. The weight ratio of excipient and kavalactone was 20:1; the excipient was a combination of emulsified starch and dextrine in a weight ratio of 10:1. Film former was carrageenan, and the weight ratio of the film former and the excipient was 3:100. Kavalactone crystal was obtained by using the separation method of Example 3.

(45) A method for preparing the microencapsulated kavalactone was as follows: I. Preparation of oil phase: dissolving 200 g of kavalactone crystal in 95 Vol. % of ethanol solution, then concentrating into a grease, and storing at 82 C. for later use; preparation of water phase: dissolving 4 kg of excipient into 40 kg of hot water with 100 C. for later use; II. Adding the oil phase into the water phase in the high-speed shearing with 12000 rpm of rotation rate, then adding 0.88 g of carrageenan, and shearing for 60 min at the high-speed, and then spray-drying at 90 C. to obtain the microencapsulated kavalactone. The microencapsulated kavalactone can be stored for 25 months at the room temperature.

Example 4 of the Microencapsulated Kavalactone

(46) Comparing the microencapsulated kavalactone of Example 2, the difference was that there was no film former in the raw material of the packing layer, other components were same as the microencapsulated kavalactone of Example 2.

(47) While preparing the microencapsulated kavalactone, the step of I was same as the microencapsulated kavalactone of Example 2, the step of II was as follows: II. Adding the oil phase into the water phase in the high-speed shearing with 10000 rpm of rotation rate, shearing for 45 min at the high-speed, and then spray-drying at 85 C. to obtain the microencapsulated kavalactone. The microencapsulated kavalactone can be stored for 26 months at the room temperature.

(48) If kavalactone crystal was not microencapsulated, shelf life of kavalactone crystal will be cut to 5-7 months. That was because part grease was contained in the obtained kavalactone crystal, the untreated grease was prone to going bad, such that the shelf life of kavalactone crystal was shorter. After microencapsulated treatment, the grease contained in the kavalactone crystal was adsorbed in the excipient, which was not prone to contact with air, thereby achieving the purpose of improving shelf time.

(49) The above are the preferred embodiments of the present application, which are not intended to limit the protection scope of the present application. Therefore, all equivalent changes made according to the structure, shape and principle of the present application should be covered within the protection scope of the present application.