JP4044998B2 - Method for producing indirubin - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing indirubin.
[0002]
[Prior art]
Indirubin is valuable as a natural red pigment, but it has been difficult to obtain it in a practical state. Also, industrially, it can be produced from indigo synthetic intermediate indoxyl and its oxide isatin, but it is very expensive and cannot be put into practical use, and indirubin cannot be obtained as a commercial product. It was.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to provide a method capable of producing such indirubin using natural Indian indigo or the like as a natural pigment without using a special synthetic method.
[0004]
[Means for Solving the Problems]
The present inventor has found that indirubin is produced by irradiating a composition containing indigo with ultraviolet rays, and has solved the above problems.
[0005]
In the present invention, the composition containing indigo is irradiated with ultraviolet rays, and then the composition is put into a solvent in which indigo is insoluble but indirubin is soluble, and indirubin is extracted, filtered, and recovered. To do.
[0006]
The composition containing indigo may be a solid composition or a liquid composition, such as commercially available indigo indigo, spider indigo, indigo, or indigo and indoxyl, isatin, indigo yellow or indigo brown. A mixture of at least one kind or the like can be used, and a residue obtained by extracting and dissolving indirubin, indigo yellow, indigo brown, and the like contained therein with boiling ethanol (solid powder containing indigo as a main component) can also be used.
[0007]
The ultraviolet irradiation of such a composition may be irradiation with sunlight, or may be irradiation with artificial ultraviolet rays such as a germicidal lamp or a fade meter.
[0008]
As for the solvent for extracting indirubin after ultraviolet irradiation, indigo is insoluble, but any indirubin may be used as long as it is soluble. Examples include boiling ethanol, dimethylformamide, dimethyl sulfoxide, pyridine, polyethylene glycol, and a mixed solvent of these and water.
[0009]
In addition, the extraction residue filtered after extracting indirubin with a solvent after UV irradiation can be irradiated with UV again to extract indirubin with a solvent.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in more detail with reference to examples.
Example 1
Indian indigo was boiled in ethanol for 1 hour and filtered hot. From the filtrate, indirubin, indigo yellow and indigo brown were qualitatively detected, and the solid composition (first extraction residue) separated by filtration was mainly composed of indigo.
The solid composition was irradiated with sunlight for 12 days (8 days on a fine day), and then 15 g of the solid composition was boiled in 85 g of ethanol for 1 hour and filtered. When this filtrate was developed on a filter paper using a 5: 1 mixed solution of ethanol and water as a developing solvent, a clear red layer of indirubin was widely formed as shown in FIG.
Furthermore, the same sunlight irradiation and ethanol extraction as the previous time were repeated again for the solid composition (second extraction residue) separated here. When the filtrate was spread on the filter paper in the same manner as the previous time, a clear red layer of indirubin was formed as shown in FIG.
[0011]
Example 2
The first extraction residue of Example 1 was subjected to ultraviolet irradiation with a 15 W germicidal lamp for 5 days, extracted with ethanol as in Example 1, and the filtrate was filtered using the same developing solvent as in Example 1. When developed above, a clear red layer of indirubin was widely formed as shown in FIG.
[0012]
Example 3
The second extraction residue of Example 1 was put into a 6: 4 mixed solvent of dimethylformamide and water, uniformly dispersed, and filtered to obtain a thick red-purple filtrate. When this filtrate was developed on the filter paper using the same developing solvent as in Example 1, a clear red layer of indirubin was widely formed as shown in FIG.
[0013]
Example 4
The method of Example 1 was carried out using Sukumo indigo instead of Indian indigo. As a result, it was found that indirubin was obtained from both the first extraction residue and the second extraction residue as in Example 1.
[0014]
Example 5
The red layer portion developed on the filter paper in Example 1 was separated, the red pigment was extracted with water-containing ethanol, and the silk fabric was immersed in the concentrated extract concentrate. As a result, the silk fiber became a pinkish beautiful red color. Stained.
[0015]
Example 6
The red layer portion developed on the filter paper in Example 3 was separated, the red pigment was extracted with water-containing ethanol, and the silk fabric was immersed in the concentrated extract concentrate. As a result, the silk fiber became a pinkish beautiful red color. Stained. Also, nylon and acrylic fibers could be dyed red by the same method.
[0016]
【The invention's effect】
In the present invention, indirubin, which is a natural red pigment, can be produced by a method called simple ultraviolet irradiation without using a special synthesis technique or apparatus.
[Brief description of the drawings]
FIG. 1 shows a paper chromatogram obtained in Example 1 of the present invention.
FIG. 2 shows a paper chromatogram obtained in Example 2 of the present invention.
FIG. 3 shows a paper chromatogram obtained in Example 3 of the present invention.

Claims (1)

The composition containing indigo is irradiated with ultraviolet rays, and then the composition is put in a solvent in which indigo is insoluble but indirubin is soluble, and indirubin is extracted, filtered, and recovered. A method for producing indirubin.

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