JP2008105957A - Hinokitiol extraction method, hinokitiol-containing water extract, and antibacterial agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hinokitiol extraction method capable of extracting hinokitiol from wood without any loss and of giving hinokitiol as a water extract. <P>SOLUTION: Wood is subjected to extraction with subcritical water or supercritical water. The extraction temperature is in the range of 60-400°C, and the extraction pressure is in the range of 0.1-22 MPa. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for extracting hinokitiol, a hinokitiol-containing aqueous extract and an antibacterial agent, and more specifically, a method for extracting hinokitiol using subcritical water or supercritical water, and a hinokitiol-containing aqueous extract obtained thereby. And an antibacterial agent containing this extract.

  Conventionally, natural ingredients contained in wood and the like have been studied for use in various fields because of their high safety. Of these, hinokitiol has been studied extensively because it has antibacterial properties, antifungal properties, anti-inflammatory properties, and the like. Hinokitiol is attracting attention for its high safety obtained from natural products as described above, and is used in the fields of hair care products, skin care products, termite control, wood preservation, etc., and also for paints, waxes, adhesives, etc. There are also uses. Such a natural product-derived hinokitiol is usually obtained by steam distillation of wood such as hiba and husahiba (for example, Patent Document 1).

However, when the wood is subjected to steam distillation, the distillate becomes two layers of a large amount of an aqueous layer and a small amount of an oil layer, and hinokitiol is dissolved in both the aqueous layer and the oil layer. Moreover, since hinokitiol dissolves in the oil layer at a higher concentration than the water layer, using only the water layer or only the oil layer does not use all of the obtained hinokitiol. Therefore, in order to use hinokitiol without waste, it is necessary to solubilize the oil layer containing hinokitiol at a high concentration in the aqueous layer by adding ethanol, for example. However, if ethanol or the like is added, it cannot be an original natural product, which may impair safety. In addition, the use is restricted, which is disadvantageous in terms of cost.
JP 2000-226301 A (paragraphs [0009] to [0010])

  The present invention has been made to solve such problems of the prior art, and an object of the present invention is to extract hinokitiol present in wood without waste and to obtain hinokitiol as an aqueous extract. It is to provide a method for extracting hinokitiol that can be used.

  The extraction method of hinokitiol of the present invention is characterized by extracting wood using subcritical water or supercritical water. When subcritical water or supercritical water is used, hinokitiol can be obtained as an aqueous solution rather than as a two-layered water layer and oil layer such as a steam distillate.

  Wood that can be used as a raw material in the present invention is not particularly limited as long as it contains hinokitiol or β-trabrin having the same action as hinokitiol, but hiba, kusahiba, hinokisunaro (Aomori hiba), Taiwan hinoki, Cypresses such as western red cedar and asunaro can be preferably used.

  Here, in the present specification, supercritical water refers to water whose temperature and pressure are in the state of the critical point (374 ° C., 22 MPa) or higher, and subcritical water refers to the present specification. In this case, the pressure is 0.2 MPa or more and the temperature is lower than 374 ° C. and 100 ° C. or more, and the water is compressed to the saturated vapor pressure or higher at that temperature.

  In the case of performing extraction using subcritical water or supercritical water, the temperature during wood extraction is preferably in the range of 60 to 400 ° C, more preferably in the range of 100 to 300 ° C, and further in the range of 170 to 230 ° C. Most preferred. Moreover, the pressure at the time of wood extraction has the preferable range of 0.1-22 MPa, The range of 0.1-15 MPa is more preferable, Furthermore, the range of 1-12 MPa is the most preferable. When the temperature at the time of extraction is lower than the above, the amount of hinokitiol that remains in the wood without being extracted increases, and when the temperature at the time of extraction is higher than the above, hinokitiol is thermally decomposed during the extraction, which is not preferable. Moreover, when the pressure at the time of extraction is lower than the above, the system may approach the water vapor phase, and when the pressure at the time of extraction is higher than the above, facilities and operating costs increase, which is not preferable in practice. That is, hinokitiol is extracted if there is a pressure equal to or higher than saturated water vapor, and even if the pressure is increased excessively, the extraction rate is not significantly affected.

  Although the time at the time of wood extraction changes with the kind and extraction conditions of wood, the range for 1 to 60 minutes is preferable, and the range for 2 to 30 minutes is more preferable. In addition, if the extraction time is shorter than the above, the amount of hinokitiol that remains in the wood without being extracted increases, and if the extraction time is longer than the above, hinokitiol is thermally decomposed during extraction, which is not preferable. .

  The hinokitiol-containing aqueous extract of the present invention can be obtained by the hinokitiol extraction method described above. The hinokitiol-containing aqueous extract of the present invention contains, in addition to hinokitiol, water-soluble hemicellulose, degradation product oligosaccharides, etc., and it is considered that components other than these hinokitiol contribute to solubilization of hinokitiol. It is done.

  According to the method for extracting hinokitiol of the present invention, hinokitiol can be obtained in a form extracted in an aqueous solution. Therefore, the hinokitiol-containing aqueous extract obtained by this method does not need to be solubilized with ethanol or the like, and can be used as it is as an antibacterial agent or the like. Furthermore, by adopting a continuous system that continuously supplies subcritical water or supercritical water, it is possible to fractionate hinokitiol-containing aqueous extracts into fractions with different concentrations, which allows high to low concentrations. Thus, it becomes possible to supply a hinokitiol-containing aqueous extract having a concentration according to the purpose.

  FIG. 1 is a conceptual diagram illustrating an apparatus for carrying out the hinokitiol extraction method of the present invention. This device is for producing subcritical water. As shown in the figure, the high pressure pump 2 that feeds water from the water tank 1 and the water from the high pressure pump 2 are heated to prepare subcritical water. And a damper 4 disposed between the high-pressure pump 2 and the electric furnace 3. Valves 5 and 6 are provided between the high-pressure pump 2 and the electric furnace 3, and between the high-pressure pump 2 and the damper 4, respectively.

  The subcritical water discharged from the electric furnace 3 is introduced into an extraction tube 7 that extracts hinokitiol from wood. A bypass channel 14 is provided in parallel with the extraction pipe 7. A valve 8 is provided on the inlet side of the extraction pipe 7, and a valve 9 for bypassing the water sent from the electric furnace 3 so as not to enter the extraction pipe 7 until the subcritical water supply is stabilized. It is provided on the bypass circuit 14. Although not shown in the drawing, a filter or the like is attached as necessary in order to prevent discharge of solid components from the wood near the outlet of the extraction tube.

  The subcritical water discharged from the extraction pipe 7 is cooled by the cooling pipe 10 via the valve 11. The aqueous extract discharged from the cooling pipe 10 is constantly discharged to the outside through the control valve 12. The control valve 12 functions to maintain the pressure in the extraction pipe 7 and the electric furnace 3 constant (here, 11 MPa) by controlling the opening and closing thereof by the actuator 13.

  Using the hinokitiol extraction apparatus of FIG. 1, hinokitiol was extracted with subcritical water from about 33.5 g of Wajima hiba as a raw material. The temperature of subcritical water was measured by thermometers T2 and T3 (FIG. 1) at the inlet and outlet of the extraction tube 7, respectively. Here, even when subcritical water (temperature T2) having a constant temperature is constantly supplied to the extraction pipe 7, the extraction pipe 7 and the wood in the inside are gradually heated. As a result of the gradient, the outlet temperature (T3) will increase with time. Therefore, the actual subcritical water temperature at the time of extraction can be expressed by a numerical value having a width between the inlet temperature and the lowest outlet temperature, for example.

  Table 1 shows the temperature at the inlet of subcritical water (T2), which is a constant value of 155 ° C, 180 ° C, 225 ° C, and 270 ° C. It shows the result of measuring the lowest value (initial temperature in the fraction) and the highest value (final temperature in the fraction) of (T3).

  Next, each fraction shown in Table 1 was analyzed by high performance liquid chromatography (HPLC) to determine the content of hinokitiol, and the results are shown in FIG. The content of hinokitiol in FIG. 2 was obtained by integrating the areas on the HPLC chart using the reagent hinokitiol as a standard in the HPLC chart illustrated in FIG. FIG. 3 shows the result of HPLC analysis of a sample for each fixed fraction of the extract extracted at an inlet temperature of 225 ° C. The chromatochart of the standard hinokitiol is represented by a broken line. Here, the conditions of HPLC analysis are as described in FIG. In addition, since the area of each chart in FIG. 3 is standardized for every measurement, it does not necessarily correspond to the absolute value of the content.

  As is apparent from the bar graph A1 of the fraction “0 to 0.5 L” in FIG. 2 and the temperature in Table 1 corresponding to this fraction, hinokitiol was extracted with subcritical water at an inlet temperature of 155 ° C. and an outlet temperature of 60 to 111 ° C. It can be seen that Further, as apparent from the bar graph D3 of the fraction “1 to 1.5 L” in FIG. 2 and the temperature of Table 1 corresponding to this fraction, hinokitiol is an aqueous extract at an inlet temperature of 270 ° C. and an outlet temperature of 228 to 236 ° C. You can see that it doesn't exist inside. Similarly, as is apparent from the bar graph D4 of fraction “1.5-2 L” and the temperature in Table 1 corresponding to this fraction, hinokitiol is still present in the aqueous extract at an inlet temperature of 270 ° C. and an outlet temperature of 236-238 ° C. You can see that it doesn't exist. This suggests that hinokitiol may be thermally decomposed, which is also expected from the fact that the “Total” bar graph D0 in FIG. 2 is small and the total amount of extracted hinokitiol is small. The From the comparison of the bar graphs A0 to D0 of “Total” in FIG. 2, it is understood that the extraction efficiency is the best when the inlet temperature is 225 ° C. (bar graph C0).

  About each fraction of each hinokitiol containing aqueous extract of inlet temperature 180 degreeC, 225 degreeC, and 270 degreeC which were obtained above, the antibacterial test with respect to Staphylococcus aureus was done by the conventional method using the cylindrical plate method. In the antibacterial test, the surface of the heart infusion medium inoculated with Staphylococcus aureus on a petri dish was divided into 12 areas, and the hinokitiol-containing aqueous extract of each fraction was dropped into each area and cultured at 30 ° C. for 20 hours. Later, the effect on S. aureus was observed. The results are shown in Table 2.

  In Table 2, each cell corresponds to the cell in Table 1 and represents antibacterial activity against the same position fraction on Table 1. From Table 2, antibacterial properties were recognized in all of the fractions having an inlet temperature of 180 ° C. and 225 ° C. For the inlet temperature of 270 ° C., the 0-0.5 L and 0.5-1 L fractions have antibacterial properties, but the 1-1.5 L and 1.5-2 L fractions have antibacterial properties. There wasn't. This result is consistent with the hinokitiol content data in FIG.

  According to the method for extracting hinokitiol of the present invention, hinokitiol derived from natural products having antibacterial properties and the like can be obtained as the properties of an aqueous extract, so that it is used in the fields of hair care products, skin care products, termite control, wood preservation, etc. can do.

It is a conceptual diagram which illustrates the apparatus for enforcing the extraction method of hinokitiol of this invention. It is a bar graph showing hinokitiol content calculated | required by the high performance liquid chromatography (HPLC) analysis about each fraction about each inlet_port | entrance temperature. The chart which measured the sample for every fixed fraction by HPLC about the extract extracted at 225 degreeC of inlet temperature is represented.

Explanation of symbols

1 Water tank
2 High pressure pump
3 Electric furnace
4 Damper 5, 6 Valve
7 Extraction tube 8, 9, 11 Valve
10 Cooling pipe
12 Control valve
13 Actuator
14 Bypass channel

Claims (6)

  A method for extracting hinokitiol, comprising extracting wood using subcritical water or supercritical water.   The method for extracting hinokitiol according to claim 1, wherein the temperature during extraction of the wood is in the range of 60 to 400 ° C.   The method for extracting hinokitiol according to claim 1 or 2, wherein a pressure at the time of extraction of the wood is in a range of 0.1 to 22 MPa.   The hinokitiol according to any one of claims 1 to 3, wherein a hinokitiol-containing aqueous extract is steadily obtained by constantly supplying subcritical water or supercritical water and extracting the hinokitiol, followed by cooling. Extraction method.   A hinokitiol-containing aqueous extract obtained by the extraction method according to claim 1.   An antibacterial agent comprising the hinokitiol-containing aqueous extract according to claim 5.

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