JPH02311474A - Production of tea catechin - Google Patents

Abstract

PURPOSE:To obtain the subject compounds simply at low cost in both high purity and recovery through such processes that, using a column packed with a synthetic adsorbent, water-soluble components extracted from tea leaves as raw material are injected, the column is washed with e.g. water, and the non-effluent components are then eluted with a specific aqueous solution. CONSTITUTION:Water-soluble components extracted from tea leaves are injected into a column packed with a synthetic adsorbent with a polymer from styrene- divinylbenzene or methacrylic ester as matrix. The column is washed using water and/or a solvent such as chloroform, and the components remained within the column are then eluted with a 10 to 65% aqueous solution containing methanol, ethanol or acetone or a mixture thereof, thus obtaining the objecting compounds i.e., L-epicatechin, L-epigallocatechin, L-epicatechin gallate and L-epigallocatechin gallate, having strong antioxidant power, vasodepressor activity, etc. Use of only hydrophilic organic solvents will ensure the safety of the work involved in the above processes.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing catechins using tea leaves as a raw material.

(Conventional technology) Catechins, which are polyphenols extracted from tea leaves, have strong antioxidant power, suppress blood cholesterol, lower blood pressure,
Recently, its antibacterial, anticancer, deodorizing, and other various functions and uses have begun to attract attention.

In order to produce tea catechins with high purity, it is essential to separate coexisting impurities such as caffeine, brown pigment, amino acids, sugars, steroids, and tea tannin oxides. For this reason, for example, as shown in Japanese Patent Application Laid-Open No. 59-219284,
A so-called liquid-liquid extraction method using a solvent has been used, in which a tea extract is washed with chloroform, a hydrophobic material such as ethyl acetate is dissolved in an organic solvent, the solvent is distilled off, and the remainder is dried. This method takes advantage of the fact that catechins, unlike sugars and free amino acids, have a strong affinity for hydrophobic organic solvents, and uses both solvents to selectively transfer catechins to hydrophobic organic solvents.

(Problem to be solved by the invention) However, in this method, since catechins have affinity for both hydrophilic and hydrophobic solvents, a large amount remains in the hydrophilic organic solvent even after extraction. It was necessary to repeat the extraction procedure several times in order to increase the yield. In addition, impurities also have a slight affinity for hydrophobic organic solvents, so even though it is selective, the purity of catechins will only be less than 50% with one extraction, so it is necessary to extract again with a hydrophilic organic solvent. However, the recovery rate of catechins had to be reduced accordingly.

In this way, conventional methods require repeated extraction operations, which are cumbersome, require the use of large amounts of expensive hydrophobic organic solvents, and are difficult to clean (up to 75% purity).
%) and recovery rate (about 75 to 78%) were low.

The present invention is a novel method for producing catechins that eliminates the above-mentioned drawbacks, and provides a method for producing catechins (L-shrimp catechin, L-epigallocatechin, L-shrimp catechin gallate, L-epigallocatechin gallate) using conventional methods. It is an object of the present invention to provide a manufacturing method that is simpler and cheaper than that, and can be obtained with high purity and high recovery rate.

(Means for Solving the Problems) In order to achieve the above object, the present invention relates to a method for extracting catechins using an adsorbent, in which water-soluble components extracted from tea leaves are injected into a column filled with a synthetic adsorbent, Tea catechins prepared by washing the column with at least one of water and a solvent, and eluting the components remaining in the column with an approximately 10-65% aqueous solution consisting of one or a mixture of methanol, ethanol, or acetone. The gist is the manufacturing method.

Examples of the synthetic adsorbent include an adsorbent based on styrene-divinylbenzene or methacrylic acid ester.

(Function) Impurities are separated from the water-soluble components of tea leaves by the synthetic adsorbent packed in the column, the impurities are washed away by water or a solvent, and tea catechins are extracted from the components remaining in the column by methanol, ethanol or acetone. class is extracted.

(Example) The present invention will be explained in further detail below.

Although it is preferable to use warm water or hot water to extract the components from the tea leaves in terms of efficiency, it can also be carried out using water or a hydrophilic organic solvent.

The water-soluble components of tea injected into the column may be the extract as it is, or may be a tea extract obtained by cooling the extract.

Water-soluble components can be washed with chloroform to remove some of the caffeine and pigments.

Caffeine interacts with catechins to form insoluble components (
Although it is preferable to remove the catechins since it forms a cream (cream-down) and reduces the recovery of catechins during concentration, this step is not absolutely necessary.

After injecting water-soluble components into a column packed with a synthetic adsorbent, the column is washed with an aqueous solution of distilled water and a hydrophilic organic solvent such as acetone, and caffeine, brown pigment, amino acids, sugars, steroids, and brown tannin oxides are removed. However, the concentration of the organic solvent should be around 5 to 10%. If it is too low, the removal effect will not be sufficient; if it is too high, some of the catechins will begin to elute, reducing the recovery rate of catechins.

Next, by adjusting the concentration of the hydrophilic organic solvent to about 10 to 65%, catechins can be eluted, and catechins can be selectively recovered with high purity and high yield. If the solvent concentration is too low, it will be difficult to elute catechins, and if it is too high, it will be impractical due to the high cost of maintaining the flow rate required for elution by the volume of the column and distilling off the solvent.

According to the method of the present invention using a synthetic adsorbent, if the concentration of the hydrophilic organic solvent is around 60%, all the catechins can be recovered in a short time and it is also economically efficient. .

Note that the amount of solvent is approximately 1.5 times the amount of filler. Most preferably 5 to 3 times.

Example 1 1 kg of tea was extracted with hot water 101 for 10 minutes, the juice obtained by squeezing was collected, and the juice was concentrated under reduced pressure and centrifuged using a conventional method to produce tea extract 1.51. After washing this with the same amount of chloroform, a synthetic adsorbent based on styrene-divinylbenzene (trade name: Duolite S-876, manufactured by Duolite International INC.) 1. Injected into a column with a diameter of 10 cm and a column height of 20 cm filled with 5 J,
It was made to flow down quickly by pump pressurization method.

After the entire amount was injected, a 10% acetone aqueous solution 4.5β was allowed to flow down to remove impurities, and a 60% acetone aqueous solution 31 was allowed to flow down to elute and separate tea catechins.

After distilling off the solvent, 102 g of crude catechins were produced. Breakdown of crude catechins: L-epicatechin 10°6%, L-epigallocatechin 24.5%, L-epicatechin gallate 11.6%, L-epigallocatechin gallate 4'3.5
%, and the purity was 90.2%. Further, 85% of catechins were recovered based on the total amount of catechins contained in the tea extract. Caffeine was removed by washing with chloroform.

The purity was determined by dissolving a portion of the crude catechin in a certain amount of water, analyzing it by high performance liquid chromatography, and determining the weight of each catechin using the absolute calibration curve method. L
The tAl ratio was calculated by dividing the total amount of catechin iJ contained in the raw material by the total amount contained in the recovered material using the above analysis method.

Comparative Example 1 In order to compare with the above example of the present invention, extraction was performed using a conventionally known method. The results were as follows.

After washing 1.5N of the same tea extract as in Example 1 with the same amount of chloroform three times (4.51 times in total), 1.5I! The extract was treated with ethyl acetate three times (total of 4.5j' was used) to transfer the extracted components. The ethyl acetate layers were combined and the ethyl acetate was distilled off under reduced pressure to produce 104 g of a crude catechin compound. The purity of the crude catechins was 75%, and 76% of the catechins were recovered based on the tea extract.

The method of the present invention was excellent in both purity and recovery rate.

Example 2 Crude catechins were produced by the same method as in Example 1.

However, the column is equipped with a synthetic adsorbent based on methacrylic acid ester (manufactured by Mitsubishi Kasei, product name: Diaion HP).
IMG) and was not washed with chloroform.

In addition, the elution solvent after the entire injection was 15% methanol 4.5
1 and 80% methanol aqueous solution 31 were used.

As a result, 121g of crude catechins were produced, with a purity of 79%.
%, and contained approximately 11% caffeine. Furthermore, 92% of catechins were recovered from the tea extract.

In this case, even if chloroform washing was not performed and caffeine was contained, the method of the present invention was superior to conventional methods in terms of purity and recovery rate.

(Effects of the Invention) As described above, according to the present invention, work safety is ensured because only a hydrophilic organic solvent is used, and since a single solvent is used, post-processing is not troublesome. In particular, crude catechins could be produced with high purity and high recovery even by using extremely inexpensive column packing materials.

Claims (2)

[Claims] (1) Inject water-soluble components extracted from tea leaves into a column packed with synthetic adsorbent, wash the column with at least one of water and a solvent, and remove the remaining components in the column with methanol, ethanol, or A method for producing tea catechins eluted with an approximately 10-65% aqueous solution consisting of one type or a mixture of acetones. (2) The first synthetic adsorbent is an adsorbent based on styrene-divinylbenzene or methacrylic acid ester.
A method for producing tea catechins as described in Section 1.