JP7264244B2 - Method for decomposing flavonoid glycosides and method for producing flavonoids - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for decomposing flavonoid glycosides and a method for producing flavonoids.

Flavonoids are a group of naturally occurring organic compounds, and are contained in flowers, leaves, roots, stems, fruits, seeds, etc. of various plants, including citrus fruits and legumes. Flavonoids have different characteristics and actions depending on their types, but most of them have strong antioxidant action. For example, polymethoxyflavone, which is a flavonoid contained in citrus fruits, is known to have antioxidant, carcinogenic, antibacterial, antiviral, antiallergic, melanin production inhibitory, and blood sugar inhibitory effects. It is expected to be applied to various uses such as pharmaceuticals, health foods, and cosmetics.

As a method for producing flavonoids from citrus fruits, for example, a method of extracting flavonoids from citrus peels or the like with an aqueous ethanol solution and recovering the extracted flavonoids from the solution is known (see, for example, Patent Document 1).

JP 2005-145824 A

However, conventional methods for producing flavonoids have the problem of low flavonoid yields. Therefore, development of a production method capable of improving the yield of flavonoids is desired.

For example, citrus peel contains flavonoids and flavonoid glycosides in a larger amount than flavonoids. If these can be recovered as flavonoids, the yield of flavonoids can be improved. Methods for decomposing flavonoid glycosides into flavonoids include a method of reacting flavonoid glycosides with an acid such as hydrochloric acid. However, this method has the problem that the used acid may remain and contaminate the product, and a side reaction product between the acid and the flavonoid may be generated. As a method for removing impurities such as acids and by-products, there is a method of separating and purifying flavonoids in decomposition products by liquid chromatography, but there are problems of high cost and poor production efficiency. Therefore, a new method for decomposing flavonoid glycosides without using acid is desired.

The present invention has been made in view of the above problems of the prior art, and is a flavonoid glycoside capable of efficiently decomposing flavonoid glycosides into flavonoids without using an acid and improving the yield of flavonoids. An object of the present invention is to provide a decomposition method and a flavonoid production method.

In order to achieve the above objects, the present invention provides a hydrothermal treatment step of decomposing the flavonoid glycosides into flavonoids by hydrothermally treating a raw material solution containing flavonoid glycosides in an autoclave, and after the hydrothermal treatment step and a decompression step of reducing the pressure in the autoclave at a decompression rate of 150 kPa/min or less.

According to the above method, flavonoid glycosides can be efficiently decomposed into flavonoids by hydrothermal treatment without using an acid. Moreover, by using this method, flavonoids can be efficiently produced at low cost.

In addition, the present inventors have found that in the method of decomposing flavonoid glycosides by hydrothermal treatment, a phenomenon occurs in which the raw material liquid suddenly boils and scatters when the pressure is reduced after the hydrothermal treatment. This scattering of the raw material liquid is one of the causes of the decrease in flavonoid yield. In order to solve this problem, the present inventors conducted extensive studies and found that the yield of flavonoids can be greatly improved by decompressing at a predetermined decompression rate during decompression. That is, by reducing the pressure in the autoclave after the hydrothermal treatment step at a decompression rate of 150 kPa/min or less, it is possible to sufficiently suppress bumping and scattering of the raw material liquid, and greatly improve the flavonoid yield. can be done.

In the decomposition method, the hydrothermal treatment may be performed by externally supplying steam into the autoclave. By supplying steam from the outside, it is possible to raise the temperature and pressure in the autoclave in a short time, and to easily form and maintain the hydrothermal treatment environment.

In the hydrothermal treatment step of the decomposition method, the pressure in the autoclave may be 0.2-1.6 MPa and the temperature may be 120-200.degree. By performing the hydrothermal treatment within the above pressure and temperature ranges, the flavonoid glycosides can be decomposed into flavonoids more efficiently, and the yield of flavonoids can be further improved.

In the decomposition method, the flavonoid glycoside may include sudatitin glycoside and/or demethoxysudatitin glycoside. According to the above decomposition method, sudatitin glycoside and demethoxysudatitin glycoside can be decomposed particularly efficiently.

The present invention also provides a method for producing flavonoids, comprising a decomposition step of decomposing flavonoid glycosides by the decomposition method of the present invention, and an extraction step of extracting flavonoids from the decomposition products obtained in the decomposition step. offer. According to such a production method, flavonoids can be efficiently produced at a high yield at low cost.

INDUSTRIAL APPLICABILITY According to the present invention, a method for decomposing flavonoid glycosides capable of efficiently decomposing flavonoid glycosides into flavonoids without using an acid and improving the yield of flavonoids, and a method for producing flavonoids are provided. can be done.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic cross section which shows an example of the autoclave used for the decomposition|disassembly method of the flavonoid glycoside of this embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will now be described in detail with reference to the drawings as the case may be. However, the present invention is not limited to the following embodiments. Also, the dimensional ratios in the drawings are not limited to the illustrated ratios.

In this specification, a numerical range indicated using "to" indicates a range including the numerical values before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described stepwise in this specification, the upper limit value or lower limit value of the numerical range in one step can be arbitrarily combined with the upper limit value or lower limit of the numerical range in another step. In the numerical ranges described herein, the upper or lower limits of the numerical ranges may be replaced with the values shown in the examples. "A or B" may include either A or B, or may include both. The materials exemplified in this specification can be used singly or in combination of two or more unless otherwise specified.

(Method for decomposing flavonoid glycosides)
The method for decomposing flavonoid glycosides according to the present embodiment includes a hydrothermal treatment step of hydrothermally treating a raw material solution containing flavonoid glycosides in an autoclave to decompose the flavonoid glycosides into flavonoids, and the hydrothermal treatment. and a decompression step of reducing the pressure in the autoclave after the step at a decompression rate of 150 kPa/min or less.

Flavonoid glycosides are hydrophilic compounds having a structure in which flavonoids and sugars are linked via glycosidic bonds. Flavonoids, which are the origin of flavonoid glycosides, are aromatic compounds having a phenylchroman skeleton as a basic structure. and the like. Among these, the flavonoid may be polymethoxyflavone, which is a flavone class.

Examples of polymethoxyflavone include sudatitin, demethoxysudatitin, nobiletin, tangeretin, pentamethoxyflavone, tetramethoxyflavone, heptamethoxyflavone and the like. Among these, the polymethoxyflavone may be sudatitin or demethoxysudatitin.

The sugar from which the flavonoid glycoside is derived is not particularly limited, and includes known sugars capable of forming a glycoside by binding to the flavonoid described above through a glycosidic bond.

The raw material liquid to be subjected to hydrothermal treatment is obtained by dissolving or dispersing a raw material containing flavonoid glycosides in water. In addition, the raw material may contain components other than the flavonoid glycoside. Other ingredients include, for example, flavonoids, water-soluble dietary fibers, sparingly soluble dietary fibers, sugars, and the like. Moreover, the raw material liquid may contain a solvent other than water. Solvents other than water include alcohols.

The content of flavonoid glycosides in the raw material is preferably 0.1% by mass or more, more preferably 0.25 to 30% by mass, more preferably 0.5 to 30% by mass, based on the total solid content of the raw material. More preferably, it is 5% by mass. When the raw material further contains flavonoids, the content of flavonoid glycosides is preferably 0.25 parts by mass or more and 0.5 to 100 parts by mass with respect to 1 part by mass of the flavonoid content. is more preferred, and 5 to 50 parts by mass is even more preferred.

The concentration of the raw material in the raw material liquid is preferably 1 to 30% by mass, more preferably 3 to 20% by mass, and even more preferably 5 to 10% by mass, based on the total amount of the raw material liquid. . When the raw material concentration is 1% by mass or more, the yield of decomposition products increases, so the amount of flavonoids obtained in a single decomposition treatment tends to increase. decomposition can be performed more reliably and efficiently.

Specific examples of raw materials that can be used include flowers, leaves, roots, stems, fruits, and seeds of plants and seaweeds. In particular, since the peel contains a large amount of polymethoxyflavone and their glycosides, the juice residue of citrus fruits can be preferably used. Moreover, the raw material may be a dry powder obtained from citrus fruits, or may be a dry powder obtained from the pericarp of citrus fruits. Examples of citrus include sudachi, mandarin orange, ponkan, and shikuwasa. The citrus fruit may be sudachi, which is rich in polymethoxyflavones such as sudachitin and demethoxysudachitin, and their glycosides.

The hydrothermal treatment can be performed by sealing the raw material liquid in an autoclave and heating it at a temperature exceeding 100° C. while the autoclave is sealed. By heating the raw material liquid in the autoclave, the inside of the autoclave becomes a heated and pressurized environment, and hydrothermal treatment (hydrothermal synthesis) is performed. The hydrothermal treatment may be performed while stirring the raw material liquid. Further, the hydrothermal treatment may be performed by supplying steam from the outside into the autoclave. For example, by supplying high-temperature, high-pressure saturated steam into the autoclave, the inside of the autoclave becomes a heated and pressurized environment, and hydrothermal treatment (hydrothermal synthesis) is performed. The autoclave is not particularly limited, and may be either vertical or horizontal. When a vertical autoclave is used, the tank may be directly filled with the raw material liquid, or the raw material liquid may be placed in a raw material container and placed on a table. When putting the raw material liquid into the raw material container, water may be put into the tank of the autoclave separately from the raw material liquid. On the other hand, when using a horizontal autoclave, the hydrothermal treatment can be performed, for example, by the following method.

FIG. 1 is a schematic cross-sectional view showing an example of an autoclave (horizontal circulation autoclave) used in the above decomposition method. In the autoclave 100 shown in FIG. 1, a cylindrical muffle furnace 3 with both ends open is arranged in a cylindrical pressure vessel (tank) 2 having a sealable door (sealing door) 1 at one end. , an air passage 4 is formed between the inner wall of the pressure vessel 2 and the outer wall of the muffle furnace 3 . One end of the muffle furnace 3 is connected to a circulation fan 8 via a cooler 6 , a heater 5 and an air passage 9 . The circulation fan 8 is attached to the rotary shaft of the motor 7 arranged outside the end of the pressure vessel 2 opposite to the sealing door 1 .

A movable table 12 is arranged inside the muffle furnace 3 , and the raw material container 11 filled with the raw material liquid 10 is placed on the movable table 12 . A boiler 13 for supplying steam is connected to the pressure vessel 2 through a pipe having a valve 14 . Further, the pressure vessel 2 is connected to a pipe having a pressure gauge 15 and a pressure valve 16 for adjusting the internal pressure.

The raw material container 11 is not particularly limited as long as it can withstand the temperature and pressure during the hydrothermal treatment and contains few impurities in the raw material liquid 10. Examples include metals such as stainless steel, titanium and alloys thereof, or A tank-shaped, bottle-shaped, cup-shaped, tray-shaped, or drum-shaped container made of a resin such as polytetrafluoroethylene can be used. In addition, at least the inner surface of the raw material container 11 may be coated with a heat-resistant, pressure-resistant, chemically stable material such as enamel or polytetrafluoroethylene.

In the hydrothermal treatment step, steam supplied from the boiler 13 into the pressure vessel 2 circulates in the autoclave 100 along the arrows in FIG. That is, the water vapor is sent to the air passage 4 by the circulation fan 8, flows toward the closed door 1, flows into the muffle furnace 3, flows around the raw material container 11, and flows through the cooler 6, the heater 5, and the air passage 9. It passes through and is sucked by the circulation fan 8 and sent out to the air passage 4 again. The amount of steam supplied is adjusted by operating the valve 14 so that the inside of the autoclave 100 has a predetermined temperature and pressure. Note that the temperature inside the autoclave 100 may be adjustable by the heater 5 and the cooler 6 . Also, the pressure inside the autoclave 100 may be adjusted by opening and closing the pressure valve 16 . By the above operation, the inside of the autoclave 100 becomes a heated and pressurized environment, and hydrothermal treatment (hydrothermal synthesis) is performed.

The reaction conditions for the hydrothermal treatment are not particularly limited, but can be, for example, 110 to 300° C. for 0.5 to 20 hours. The reaction temperature is preferably 120 to 200°C, more preferably 120 to 190°C, even more preferably 140 to 185°C. When the reaction temperature is 110° C. or higher, the hydrothermal reaction tends to occur more favorably, and when it is 300° C. or lower, carbonization of the raw materials and flavonoids is difficult to proceed, and the yield tends to be further improved. . The reaction time is preferably 0.5 to 20 hours, more preferably 1 to 10 hours. When the reaction time is 0.5 hours or longer, the reaction tends to proceed more easily, and when the reaction time is 20 hours or shorter, it tends to be easier to balance the progress of the reaction and the cost.

The pressure in the autoclave during the hydrothermal treatment may be the saturated vapor pressure corresponding to the above reaction temperature or higher, but from the viewpoint of the pressure resistance of the apparatus, the saturated vapor pressure is preferable. When steam is supplied from the boiler into the autoclave, it is preferable to supply saturated steam at the reaction temperature described above. The pressure inside the autoclave during hydrothermal treatment can be, for example, 0.2 to 1.6 MPa.

By performing hydrothermal treatment under the above conditions, flavonoid glycosides can be efficiently decomposed into flavonoids (more specifically into flavonoids and sugars).

Next, after performing the hydrothermal treatment step by the method described above, the depressurization step of reducing the pressure in the autoclave at a depressurization rate of 150 kPa/min or less is performed. The pressure in the autoclave can be reduced by opening a pressure valve to discharge the water vapor in the autoclave. The rate of decompression during decompression can be adjusted with a pressure valve. It is preferable to reduce the pressure while checking the pressure inside the autoclave with a pressure gauge. By reducing the pressure at the above pressure reduction speed, bumping and scattering of the raw material liquid can be sufficiently suppressed, and the flavonoid yield can be improved. From the viewpoint of further improving the yield of flavonoids, the pressure reduction rate is preferably 100 kPa/min or less, more preferably 50 kPa/min or less, even more preferably 30 kPa/min or less, and 20 kPa/min. Minutes or less are particularly preferred, and 10 kPa/min or less is extremely preferred. The lower limit of the decompression rate is not particularly limited, but from the viewpoint of shortening the time required for the decompression step, it may be 1 kPa/min or more, or 5 kPa/min or more. In the depressurization step, the depressurization speed does not always need to be constant, and the depressurization speed may be varied within the range of 150 kPa/min or less.

As the pressure inside the autoclave is reduced due to the discharge of water vapor, the temperature inside the autoclave also drops. As a result, the temperature around the raw material container decreases, the raw material liquid boils and gradually volatilizes, and the liquid temperature of the raw material liquid also follows the surrounding temperature. By setting the decompression rate within the above range, the pressure inside the autoclave is maintained at the saturated vapor pressure or more, and it is possible to suppress the raw material liquid from becoming overheated and prevent bumping. The pressure may be reduced while cooling the inside of the autoclave with a cooler.

After the inside of the autoclave is depressurized to atmospheric pressure (0.1 MPa) by the depressurization step, the raw material liquid can be cooled to room temperature by natural cooling. Thereby, a decomposition product of the flavonoid glycoside (glycoside decomposition product) can be obtained.

(Method for producing flavonoid)
The flavonoid production method according to the present embodiment includes a decomposition step of decomposing flavonoid glycosides, and an extraction step of extracting flavonoids from the decomposition products obtained in the decomposition step. The decomposition step is a step of decomposing flavonoid glycosides by the method for decomposing flavonoid glycosides according to the present embodiment described above.

In the extraction step, flavonoids are extracted from the decomposition products obtained in the decomposition step. Decomposition products include, in addition to flavonoids, sugars, flavonoid glycosides left undecomposed, water-soluble and sparingly soluble celluloses, decomposition products thereof, and the like. Here, flavonoids are hydrophobic, whereas sugars, flavonoid glycosides, water-soluble cellulose and their decomposition products are hydrophilic. Therefore, the components insoluble in the aqueous solution after the hydrothermal treatment contain flavonoids at a high concentration, and the flavonoids can be concentrated by separating the aqueous solution and the insoluble matter after the hydrothermal treatment. Furthermore, the water-insoluble matter is dissolved in a solvent that dissolves the flavonoid, such as ethanol, ethyl acetate, hexane, toluene, etc., and a mixed solvent thereof, and the insoluble matter is removed by filtration or the like to further extract the flavonoid.・Can be refined. After that, by drying the filtrate, a high-concentration flavonoid can be obtained.

By the above method, flavonoids can be efficiently produced with high yield. The flavonoid produced by the production method of the present embodiment may be polymethoxyflavone, or sudatitin and/or demethoxysudatitin. The production method of the present embodiment is suitable for producing polymethoxyflavone, particularly sudatitin and demethoxysudatitin, and can greatly improve the yield.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments. For example, the autoclave 100 shown in FIG. 1 is equipped with one circulation fan 8, but an autoclave equipped with a plurality of circulation fans may be used. For example, when circulation fans are installed at a plurality of locations in the muffle furnace 3, the temperature in the muffle furnace 3 can be easily made uniform, and even when a plurality of raw material liquids are accommodated, the temperature of each raw material liquid can easily be made uniform. . Also, although the autoclave 100 shown in FIG. 1 includes the cooler 6 and the heater 5, one or both of them may be omitted.

EXAMPLES The present invention will be described in more detail below based on examples and comparative examples, but the present invention is not limited to the following examples.

(Example 1)
Citrus peel extract powder (manufactured by Ikeda Yakuso Co., Ltd.) having a sudachitin content of 1,000 mass ppm and a glycoside-derived sudachitin content of 9,000 mass ppm was dissolved/dispersed in ultrapure water to a concentration of 5% by mass. An aqueous dispersion was prepared. This aqueous dispersion was placed in a 15 L stainless steel tank (manufactured by Nitto Metal Industry Co., Ltd., container depth: 27 cm) and a 1 L polytetrafluoroethylene (PTFE) bottle (manufactured by AS ONE Corporation, trade name: Big Boy wide mouth 1000 ml, container depth 20 cm). ) was charged in a predetermined amount shown in Table 1.

Samples 1 to 3 shown in Table 1 were placed in a hot air circulating autoclave (manufactured by Ashida Seisakusho Co., Ltd.) with a tank internal volume of 2 m ³ , and the sudachi pericarp extract aqueous dispersion was subjected to glycoside decomposition treatment at 180 ° C. for 1 hour. bottom. In the decomposition treatment, saturated steam at 180°C is supplied from the boiler into the autoclave tank (pressure vessel), and the pressure inside the tank is 1 MPa, which is the saturated steam pressure of water at 180°C. I went while adjusting the After the decomposition treatment, the pressure inside the tank is 1 MPa (temperature inside the tank: 180°C) at a decompression rate of 7.5 kPa/min to 0.1 MPa (temperature inside the tank: 100°C), which is the saturated water vapor pressure of water at 100°C. was adjusted to reduce the pressure and temperature. The time required for pressure reduction was 2 hours. After the internal pressure of the tank reached 0.1 MPa, the lid of the tank was opened and the containers (Samples 1 to 3) were taken out and cooled naturally to room temperature (25°C).

After cooling, the solution and solid content in each container are decompressed using a diaphragm pump using a hydrophilic PTFE membrane filter with an opening of 0.2 μm (manufactured by Merck-Millipore, trade name: Omnipore 0.2 μm JG). filtered. Decomposed glycoside-derived sugars were dissolved in the separated solution, and the solid matter contained a high concentration of decomposed sudatitin. and dried in an oven at 120° C. for 5 hours to obtain a powdery glycoside degradation product. Next, the glycoside degradation product was dispersed in ethanol to prepare a 5% by mass dispersion, treated under reflux at 60° C. for 1 hour, and sudatitin was extracted into ethanol. Thereafter, the dispersion was filtered under reduced pressure using a diaphragm pump using a hydrophilic PTFE membrane filter with an opening of 0.2 μm (manufactured by Merck-Millipore, trade name: Omnipore 0.2 μm JG) to obtain a sudatitin solution. got The sudatitin solution was vacuum-dried at 60° C. using a diaphragm pump to obtain a powdery sudatitin concentrated powder.

(Examples 2-4)
A glycoside hydrolyzate and a sudatitin concentrated powder were obtained in the same manner as in Example 1, except that the pressure reduction rate after the decomposition treatment was changed to the conditions shown in Table 2.

(Comparative example 1)
After the decomposition treatment, a glycoside decomposition product and a sudatitin concentrated powder were obtained in the same manner as in Example 1, except that the pressure was reduced by fully opening the pressure valve. The pressure reduction rate was 180 kPa/min.

<Evaluation method>
(Measurement of sudatitin concentration of sudatitin concentrated powder)
The sudatitin concentration of the sudatitin-concentrated powder obtained in each example and comparative example was measured by the following method. First, 0.1 g of sudatitin concentrated powder was dissolved/dispersed in ethanol at a dilution ratio of 500 and filtered through a PTFE filter with a pore size of 0.1 μm to obtain an ethanol solution. This ethanol solution was subjected to component analysis by high performance liquid chromatography (HPLC). A calibration curve was prepared using a commercially available sudatitin standard purified sample as a standard substance, and the sudatitin concentration in the sudatitin concentrated powder was roughly estimated using it. Hitachi High-Tech's "Chrome master" was used for the HPLC apparatus. Table 2 shows the results.

(Calculation of sudatitin yield)
The yield of sudatitin was determined from the mass of the sudatitin concentrated powder and the sudatitin concentration. The yield indicates the ratio of the mass of sudatitin contained in the obtained sudatitin-concentrated powder to the total mass of sudatitin and glycoside-derived sudatitin in the sample before decomposition treatment. Table 2 shows the results.

In Comparative Example 1 in which the pressure was reduced by fully opening the pressure valve during the pressure reduction after the decomposition treatment, the yield decreased in all containers. Moreover, it was confirmed that the sample was scattered from the container when the pressure was reduced. On the other hand, in Examples 1 to 4 in which the pressure reduction rate was adjusted to 150 kPa/min or less, scattering of the sample from the container was greatly suppressed compared to Comparative Example 1, and the decrease in yield was small. was confirmed. In particular, in Examples 1 and 2 in which the decompression rate was adjusted to 15 kPa/min or less, almost no scattering from the container was observed in any of the samples, and it was confirmed that the yield was high.

DESCRIPTION OF SYMBOLS 1... Sealing door, 2... Pressure vessel, 3... Muffle furnace, 4... Air course, 5... Heater, 6... Cooler, 7... Motor, 8... Circulation fan, 9... Air course, 10... Raw material liquid, 11... Raw material Container 12 Movable table 13 Boiler 14 Valve 15 Pressure gauge 16 Pressure valve.

Claims (5)

A hydrothermal treatment step of hydrothermally treating a raw material solution containing flavonoid glycosides in an autoclave to decompose the flavonoid glycosides into flavonoids;
a decompression step of reducing the pressure in the autoclave after the hydrothermal treatment step at a decompression rate of 150 kPa/min or less;
A method for decomposing flavonoid glycosides. 2. The decomposition method according to claim 1, wherein the hydrothermal treatment is performed by supplying steam from the outside into the autoclave. The decomposition method according to claim 1 or 2, wherein in the hydrothermal treatment step, the pressure in the autoclave is 0.2 to 1.6 MPa and the temperature is 120 to 200°C. 4. The decomposition method according to any one of claims 1 to 3, wherein the flavonoid glycoside comprises sudatitin glycoside and/or demethoxysudatitin glycoside. A decomposition step of decomposing flavonoid glycosides by the method according to any one of claims 1 to 4;
an extraction step of extracting flavonoids from the decomposition products obtained in the decomposition step;
A method for producing a flavonoid, comprising:

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