JP7851342B2 - Method for producing ginger extract - Google Patents

Description

This invention relates to a method for producing ginger extract.

Shokyo is the rhizome of ginger (Zingiber officinale Roscoe), a member of the Zingiberaceae family, and has been used as an aromatic stomachic since ancient times. Its main components are known to be gingerols (6-gingerol, 8-gingerol, 10-gingerol, etc.) and shogaol. Due to its effects such as increasing blood flow, ginger extracts are used in hair growth products and other applications.

However, because gingerols have strong skin irritant properties, ginger extracts that substantially do not contain gingerols have been investigated. A method for producing an aqueous ginger extract has been reported (Patent Document 1), which involves extracting ginger with 20%, 50%, or 70% (v/v) aqueous alcohol, followed by charcoal treatment of the extract with activated charcoal.

On the other hand, ginger contains fructosyl dipeptides such as Fru-Val-Tyr and Fru-Ile-Tyr, and these fructosyl dipeptides have been reported to have wrinkle-preventing and wrinkle-improving effects, as well as hair growth-inhibiting effects (Patent Document 2).

Japanese Patent Publication No. 2003-48845 Japanese Patent Publication No. 2010-180240

Patent Document 2 describes the production of fructosyl dipeptides by separating and purifying ginger extract using chromatography. However, this method is complicated and has drawbacks in terms of industrial productivity. Furthermore, while the method in Patent Document 1 can reduce gingerols, particularly 6-gingerol, which are pungent and irritating components in ginger extract, it also has the problem of producing only a small amount of fructosyl dipeptides.
Accordingly, the present invention relates to providing a method for producing ginger extract containing a large amount of fructosyl dipeptide while reducing 6-gingerol.

The inventors of this invention investigated various methods for extracting ginger and found that by extracting ginger with water or an aqueous ethanol solution of 30% (v/v) or less, and then contacting the extract with activated carbon in an aqueous alcohol solution of 40-60% (v/v), a ginger extract with a high amount of fructosyl dipeptide and a low amount of 6-gingerol can be obtained.

In other words, the present invention relates to the following 1) and 2).
1) The following steps (1) and (2):
A method for producing ginger extract, comprising the steps of (1) extracting ginger with water or an aqueous solution of ethanol with a concentration of 30% (v/v) or less, and (2) contacting the extract obtained in step (1) with activated carbon in an aqueous solution of alcohol with a concentration of 40-60% (v/v).
2) Ginger extract containing 100 ppb or more of fructosyl dipeptide and less than 1 ppm of 6-gingerol.

According to the present invention, it is possible to produce a ginger extract containing a large amount of fructosyl dipeptide while reducing 6-gingerol. Therefore, the ginger extract of the present invention is expected to exhibit the beneficial physiological functions of fructosyl dipeptide.

A diagram showing the results of component analysis of water or ethanol extract of ginger. A diagram showing the results of the component analysis of ginger extract.

The present invention provides a method for producing ginger extract, comprising: (1) extracting ginger with water or an aqueous ethanol solution of 30% (v/v) or less; and (2) contacting the extract obtained in step (1) with activated carbon in an aqueous alcohol solution of 40-60% (v/v). Steps (1) and (2) will be described below.

[Step (1)]
Step (1) is the step of extracting ginger with water or an aqueous solution of ethanol with a concentration of 30% (v/v) or less.
In this specification, "ginger" refers to the rhizome of ginger (Zingiberaceae), sometimes with the periderm removed. Ginger is preferably heated and dried, but may also be processed by cutting, crushing, or other methods.
The extraction method is not particularly limited, and conventional methods such as immersion, decoction, leaching, reflux extraction, ultrasonic extraction, microwave extraction, and stirring can be used.

Water or an aqueous solution of ethanol with a concentration of 30% (v/v) or less is used as the extraction solvent.
Examples of water include tap water, distilled water, deionized water, and purified water.
In this invention, "% (v/v)" means volume percentage at 25°C.

In this invention, the extraction solvent is preferably an aqueous ethanol solution with a concentration of more than 0% (v/v) and 30% (v/v) or less, and more preferably an aqueous ethanol solution with a concentration of 10% (v/v) or more and 30% (v/v) or less, from the viewpoint of preservation and increasing the concentration of fructosyl dipeptides in the extract while reducing gingerols.

The amount of solvent used for extraction can be appropriately selected depending on the extraction method, but from the viewpoint of yield and manufacturing efficiency of fructosyl dipeptides, it is preferable to use 2 to 100 times the amount of ginger (on a dry weight basis), and more preferably 5 to 20 times the amount of solvent.
The extraction conditions are not particularly limited as long as they allow for sufficient extraction, but for example, the extraction time is preferably 0.5 hours to 10 days, and more preferably 1 to 7 days.
The extraction temperature is preferably 5 to 60°C, and more preferably 5 to 30°C. Generally, extraction is performed for a longer time at low temperatures and for a shorter time at high temperatures.

After the extraction process, the extract can be separated into solid and liquid components. Examples of solid-liquid separation methods include filter filtration using filter paper, filter separation using metal filters such as stainless steel, centrifugal separation, and membrane treatment, and these can be performed individually or in combination of two or more methods.
Furthermore, the extract can be concentrated. The concentration method is not particularly limited and includes, for example, atmospheric pressure concentration, in which the solvent is evaporated at atmospheric pressure; reduced pressure concentration, in which the solvent is evaporated at reduced pressure; and membrane concentration, in which the solvent is removed by membrane separation. In addition, drying may be performed as needed. Examples of drying methods include spray drying and freeze-drying.

[Step (2)]
This step involves contacting the extract obtained in step (1) with activated carbon in a 40-60% (v/v) aqueous alcohol solution.
Examples of raw materials from which activated carbon is derived include sawdust, coal, and coconut shells. Among these, coconut shell-derived activated carbon is preferred from the viewpoint of reducing gingerols without reducing the concentration of fructosyl dipeptides. Furthermore, activated carbon activated with gases such as water vapor or chemicals is preferably used. The shape of the activated carbon is not particularly limited and examples include powder, granular, and fibrous forms.
As activated carbon, commercially available products such as Shirasagi P (Osaka Gas Chemical Co., Ltd.) and Kuraray Coal GW (Kuraray Co., Ltd.) can be used.
From the viewpoint of not reducing the concentration of fructosyl dipeptides and reducing gingerols, the amount of activated carbon used is preferably 0.1 to 100 times the mass of the solid content of the extract obtained in step (1), more preferably 0.1 to 10 times the mass, and more preferably 1 to 5 times the mass.
In this specification, "solid content" refers to the residue obtained after concentrating the sample under reduced pressure using a rotary evaporator, followed by hydration and freeze-drying to remove volatile substances.

Examples of alcohols include monohydric, dihydric, and polyhydric alcohols. Examples of monohydric alcohols include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, and t-butanol. Examples of dihydric alcohols include alkylene glycols such as ethylene glycol, propylene glycol, 1,3-propanediol, and 1,3-butylene glycol. An example of a trihydric alcohol is glycerin. Alcohols can be used individually or in combination of two or more.
From the viewpoint of reducing gingerols while retaining fructosyl dipeptides, monohydric and dihydric alcohols are preferred, ethanol and 1,3-butylene glycol are more preferred, and ethanol is even more preferred.
The alcohol concentration of the aqueous alcohol solution in this process is 40-60% (v/v), from the viewpoint of reducing gingerols while retaining fructosyl dipeptides.
For example, the concentration of the alcohol aqueous solution can be adjusted by adding and mixing alcohol and water to the extract so that the alcohol concentration in the alcohol aqueous solution falls within the above range, or by adding and mixing alcohol to the extract, and then adding water to adjust the alcohol concentration to fall within the above range.

From the viewpoint of yield and manufacturing efficiency of fructosyl dipeptides, the amount of aqueous alcohol solution used is preferably 10 to 10,000 times the mass of the solid content of the extract obtained in step (1), and more preferably 100 to 1,000 times the mass.

Methods for contacting the extract obtained in step (1) with activated carbon include, for example, batch processing, continuous processing, etc.
In a batch process, for example, activated carbon can be added to an alcohol aqueous solution containing the extract, stirred to allow adsorption, and then the activated carbon can be recovered by filtration. The processing atmosphere can be air or an inert gas (nitrogen gas, argon gas, helium gas, carbon dioxide).
In the case of a continuous process, for example, contact can be maintained by continuously processing using a column packed with activated carbon. The liquid flow conditions can be set as appropriate.

The contact temperature between the extract obtained in step (1) and the activated carbon is preferably 5°C to 35°C, and more preferably 10°C to 30°C, from the viewpoint of gingerol removal efficiency, fructosyl dipeptide yield, and manufacturing efficiency.

The contact time between the extract obtained in step (1) and activated carbon can be appropriately selected depending on the contact method and scale, but from the viewpoint of gingerol removal efficiency, fructosyl dipeptide yield, and manufacturing efficiency, 0.5 hours to 7 days is preferred, and 2 hours to 1 day is more preferred.

The ginger extract of the present invention can be obtained by recovering the treated liquid after contact with activated carbon, through solid-liquid separation operations such as centrifugation and filtration.
The form of the ginger extract of the present invention is not particularly limited and may be solid, semi-solid, or liquid. Furthermore, the processed liquid recovered as described above can be concentrated or dried. The concentration method and drying method are as described above.

The ginger extract of the present invention has a high amount of fructosyl dipeptide and a low amount of 6-gingerol. Hereinafter, "fructosyl dipeptide" is a collective term for Fru-Val-Tyr, Fru-Ile-Tyr, Fru-Val-Phe, Fru-Ile-Val, and Fru-Val-Ile. Fru represents a fructosyl residue, Val represents a valine residue, Tyr represents a tyrosine residue, Ile represents an isoleucine residue, and Phe represents a phenylalanine residue. The fructosyl residue may be the D-form or L-form, α-form or β-form, and may be either the furanose type or the pyranose type. In solution, the α-form, β-form, furanose type, and pyranose type interconvert to each other, resulting in a mixture thereof. For example, in water, it becomes a mixture of β-pyranose type (67%), β-furanose type (12%), α-furanose type (15%), and α-pyranose type (6%). The stereochemistry of each amino acid residue can be either D-form or L-form, but L-form is preferred. In this invention, it is sufficient to contain at least one of the five types of fructosyl dipeptides described above. The fructosyl dipeptide may also be in the form of a salt or hydrate. The salt is not particularly limited as long as it is physiologically acceptable, but examples include alkali metal salts, alkaline earth metal salts, amine salts, amino acid salts, and acid addition salts.

The fructosyl dipeptide content in the ginger extract of the present invention is preferably 100 ppb or more, and more preferably 200 ppb or more. The fructosyl dipeptide content can be measured by the method described in the examples below, and the fructosyl dipeptide content is defined based on the total amount of the five types described above.

The 6-gingerol content in the ginger extract of the present invention is preferably less than 1 ppm, more preferably less than 0.1 ppm, and even more preferably substantially absent (for example, below the detection limit of HPLC). The 6-gingerol content can be measured by the method described in the examples below.

Furthermore, the mass ratio of fructosyl dipeptide content to 6-gingerol content in the ginger extract of the present invention is preferably 1 or more.

The ginger extract of the present invention can be used in various fields such as pharmaceuticals, quasi-drugs, cosmetics, and foods. It is particularly suitable for use in topical skin preparations. The ginger extract of the present invention may be used alone, or it may be used in combination with various additives used in formulations, such as oils, pigments, fragrances, preservatives, chelating agents, pigments, antioxidants, vitamins, minerals, sweeteners, seasonings, preservatives, binders, bulking agents, disintegrants, surfactants, lubricants, dispersants, buffers, coating agents, carriers, and diluents.

With regard to the embodiments described above, the present invention further discloses the following aspects.

<1> The following steps (1) and (2):
A method for producing ginger extract, comprising the steps of (1) extracting ginger with water or an aqueous solution of ethanol with a concentration of 30% (v/v) or less, and (2) contacting the extract obtained in step (1) with activated carbon in an aqueous solution of alcohol with a concentration of 40-60% (v/v).

<2> The manufacturing method according to <1>, wherein the water or aqueous ethanol solution of 30% (v/v) or less is preferably an aqueous ethanol solution of more than 0% (v/v) and 30% (v/v) or less, and more preferably an aqueous ethanol solution of 10% (v/v) or more and 30% (v/v) or less.
<3> The manufacturing method according to <1> or <2>, wherein the amount of activated carbon used is preferably 0.1 to 100 times the mass of the solid content of the extract obtained in step (1), more preferably 0.1 to 10 times the mass, and even more preferably 1 to 5 times the mass.
<4> The manufacturing method according to any one of <1> to <3>, wherein the aqueous alcohol solution is preferably one or more selected from monohydric alcohols and dihydric alcohols, more preferably one or more selected from ethanol and 1,3-butylene glycol, and even more preferably ethanol.

<5> Ginger extract containing 100 ppb or more of fructosyl dipeptide and less than 1 ppm of 6-gingerol.

<6> The ginger extract according to <5>, wherein the fructosyl dipeptide content is preferably 200 ppb or more, and the 6-gingerol content is preferably less than 0.1 ppm.

In the following examples, "%" means "%(v/v)".

<Fructosyl dipeptide analysis conditions>
The sample was diluted 10-fold with ultrapure water and methanol in a 1:1 ratio, filtered, and then measured by LC-MS/MS under the following conditions.
[Measurement conditions]
Column: Inertsustein AQ-18 HP (3mm x 250mm, 3μm)
Column temperature: 40°C
Mobile phase: A; 0.1% formic acid/ _H₂O
B; CH ₃ CN

Flow rate: 0.4mL/min
Injection volume: 3μL
Ionization: ESI (+)
MS/MS: 443.2/359.4Da (Fru-Val-Tyr)
457.3/373.1Da (Fru-Ile-Tyr)
393.1/309.1Da (Fru-Ile-Val)
393.2/309.3 (Fru-Val-Ile)
427.2/343.2 (Fru-Val-Phe)

<6. Analytical conditions for gingerol>
The sample was diluted 100-fold with ultrapure water and methanol in a 1:1 ratio, filtered, and then measured by HPLC under the following conditions.
[Measurement conditions]
Column: Inertil ODS3 (3 mm x 150 mm, 5 μm)
Column temperature: 40°C
Mobile phase: A; 0.1% formic acid/ _H₂O
B; CH ₃ CN

Flow rate: 0.4mL/min
Injection volume: 5μL
Detection: UV 280 nm

Reference example 1
50 mg of ginger (manufactured by Tochimoto Tenkaido Co., Ltd.) was extracted at 25°C for 1 day with 1 mL of ion-exchanged water and 10-100% ethanol aqueous solution, and then filtered to obtain the extract. The analytical results of the extract are shown in Figure 1.

As shown in Figure 1, it was confirmed that extracts obtained by extracting ginger with water or an ethanol aqueous solution of 30% or less contained more fructosyl dipeptides compared to extracts obtained by extracting with an ethanol aqueous solution of 40% or more.

Examples 1-6
10 g of ginger (manufactured by Tochimoto Tenkaido Co., Ltd.) was extracted in 200 mL of 10% ethanol aqueous solution at 25°C for 3 days, then filtered to obtain the extract.
Four mL of each obtained extract was concentrated and redissolved in four mL of each solvent. 500 μL of each redissolved solution was taken, and 10 mg of activated carbon (Shirasagi P, Osaka Gas Chemical Co., Ltd.) was added to each. After one hour, the solutions were filtered to obtain ginger extract (Table 3). The analytical results of the ginger extract are shown in Figure 2.

Comparative Example 1
10 g of ginger (manufactured by Tochimoto Tenkaido Co., Ltd.) was extracted in 200 mL of 20% ethanol aqueous solution at 25°C for 3 days, and then filtered to obtain an extract. 10 mg of activated carbon (Shirasagi P) was added to 500 μL of this extract, and after 1 hour, it was filtered to obtain ginger extract (Table 3). The analytical results of the ginger extract are shown in Figure 2.

Comparative Example 2
Ginger extract was obtained by the same procedure as in Comparative Example 1, except that a 50% 1,3-butylene glycol aqueous solution was used as the extraction solvent (Table 3). The analytical results of the ginger extract are shown in Figure 2.

Comparative Example 3
Ginger extract was obtained by the same procedure as in Comparative Example 1, except that a 70% 1,3-butylene glycol aqueous solution was used as the extraction solvent (Table 3). The analytical results of the ginger extract are shown in Figure 2.

As shown in Figure 2, it was confirmed that by extracting ginger with a low-concentration ethanol aqueous solution and then contacting the extract with activated carbon in a 40-60% alcohol aqueous solution, a ginger extract containing a high amount of fructosyl dipeptide while substantially free of 6-gingerol was obtained. In contrast, the ginger extracts of Comparative Examples 1-3, which were treated with activated carbon in a 20% ethanol extract or a 50% or 70% 1,3-butylene glycol extract, contained substantially no 6-gingerol or only a small amount of 6-gingerol, and also contained a small amount of fructosyl dipeptide.

Claims (3)

The following steps (1) and (2):
A method for producing ginger extract, comprising: (1) extracting ginger with water or an aqueous ethanol solution of 30% (v/v) or less; and (2) contacting the extract obtained in step (1) with activated carbon in an aqueous alcohol solution of 40-60% (v/v) ,
The aforementioned aqueous alcohol solution is an aqueous ethanol solution or an aqueous 1,3-butylene glycol solution.
A method for producing the ginger extract, wherein the ginger extract contains 100 ppb or more of fructosyl dipeptide and has a 6-gingerol content of less than 1 ppm. A method for producing ginger extract according to claim 1, wherein the amount of activated carbon used is 0.1 to 100 times the mass of the solid content of the extract obtained in step (1). A method for producing a topical skin preparation containing ginger extract produced by the manufacturing method described in claim 1 or 2.