JPH02215727A - Concentration of gymnema sylvestre leaf extract - Google Patents

Abstract

PURPOSE:To effectively concentrate the thermally unstable active ingredient of Gymnema Sylvestre without decomposing the active ingredient by concentrating the extraction solution of the leaves of the Gymnema Sylvestre with a reverse osmosis membrane. CONSTITUTION:The leaves of Gymnema Sylvestre are, if necessary, dried and extracted with water or a mixture of water and an alcohol and the extraction solution is filtered with a filter paper and further filtered with a precise filter paper. The filtrate is filtered with a reverse osmosis having a NaCl-stopping ability of >=60% under conditions comprising a pressing pressure of 1-50kgf/cm<2>, a flow amount of 1-10l/min and a temperature of 10-30 deg.C to effectively concentrate the filtrate without decomposing an active ingredient. The concentrated product has remarkable pharmacological activities (dental caries-resistant activity and sugar absorption-suppressing activity in intestinal tracts), thereby permitting to effectively utilize the concentrated product for medicines, low calorie beverages, etc.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention provides an effective method for extracting active ingredients from Gymnema sylvestre leaves without contaminating them with microorganisms and preventing thermal decomposition of the active ingredients. Concerning a method of concentrating.

(Conventional technology) Gymnema sylvestre (Rainbow y mutual ■ Gong μ individuals; hereinafter G
S) is a vine-like plant of the Asclepiadaceae family that grows naturally in tropical to subtropical regions such as India, China, Southeast Asia, and Africa. GS leaf extract is known to have effects such as masking sweetness, anti-inflammatory properties, and inhibiting sugar absorption in the intestinal tract, and has been used for the treatment of diabetes since ancient times.

The main active ingredient contained in GS leaves is called gymnemic acid (hereinafter abbreviated as GA), which is a glycoside in which glucuronic acid is bonded to a triterpene skeleton.

It is thought that GA has several homologs depending on the difference in the acyl group in the trivertene skeleton, and their molecular weights are said to be 700 to 800. However, these have not been identified and generally GA from 03 leaves
Extracts containing mixtures of congeners are used.

An example of extracting the active ingredient from 03 leaves and shrinking the leaves by 1 m is disclosed in Japanese Patent Application Laid-Open No. 62-246591. In this publication, the OS active ingredients are extracted by contacting dried GS leaves with aqueous ethanol with a concentration of 60% or more at a temperature of 30 to 70°C, and the resulting extract is heated at a temperature of 40 to 70°C. By concentrating under reduced pressure, a concentrated solution with a solute concentration of 10% or more is obtained. As seen in this bulletin, 0
3. The leaf extract is extracted under certain high temperature conditions.2.
It is concentrated under reduced pressure at a temperature of 60°C or higher. Conventionally, in such a concentration process.

It was believed that the components contained therein were relatively stable. However, when the present inventors concentrated the 03 leaf extract using such a method, it was confirmed that some of the contained components were decomposed. moreover.

Since GA is a type of saponin, it tends to foam when the pressure is reduced, which significantly reduces the concentration efficiency. As the concentration progresses, the alcohol in the extract evaporates, resulting in a decrease in the alcohol content of the resulting concentrate, which is disadvantageous in that it is susceptible to contamination by microorganisms when the concentrate is stored. In addition, 0 obtained in this way
The three-leaf extract and concentrate have a black-rimmed turbidity and a characteristic bitter taste, which is visually and tastefully undesirable.

(Problem to be solved by the invention) The present invention solves the above-mentioned conventional problems.

The purpose is to provide a method for effectively concentrating a 03 leaf extract without decomposing the active ingredients.

Another object of the present invention is to suppress the bitterness characteristic of GS.

Moreover, a transparent aS active ingredient concentrate can be obtained. An object of the present invention is to provide a method for concentrating a B. 03 leaf extract.

(Means for Solving the Problems) The inventors investigated the stability of active ingredients in Gymnema sylvestre leaf extract against temperature.

Some preliminary experiments were conducted. First, when an extract from dried leaves of Gymnema sylvestre was analyzed by high performance liquid chromatography (IPLc), the presence of several component peaks was confirmed. Among them, the peak of gymnemic acid (GA), which is considered to be an active ingredient, is.

It is said that it appears after a retention time of 10 minutes. When this 03 leaf extract was heat-treated at 60°C, 80°C, and 94°C for 5 hours and analyzed by HI'LC, the peak that appeared between 19 and 30 minutes was significantly reduced. was confirmed. For example, retention time 21 due to heat treatment
FIG. 1 shows the decrease over time in the peak area appearing at minutes and 26 minutes as a percentage (%) of the peak area before heat treatment. In Figure 1, Figure (A) shows the decrease in peak area due to heat treatment at a retention time of 21 minutes;
(B) The figure shows the decrease in peak area at a retention time of 26 minutes due to heat treatment. In the figure, the white circle mark (0) indicates the treatment at 60°C, the black triangle mark (mu) indicates the treatment at 80°C, and the black circle mark (.
) indicates treatment at 94°C. Thus, it was revealed that the active ingredients in the 03 leaf extract are decomposed by heat treatment. Therefore, the two inventors investigated various methods for effectively concentrating the 03 leaf extract without heating, and as a result, they developed the method of the present invention.

The method for concentrating Gymnema sylvestre leaf extract of the present invention includes concentrating Gymnema sylvestre leaf extract using a reverse osmosis membrane, thereby achieving the above object. achieved.

Here, GS leaves refer to those in which a small amount of petioles and branches are mixed. This is because GS is a climbing plant and usually grows entwined with tall trees, so when the leaves are collected, some of the petioles and branches are mixed in.

To extract the active ingredient from the 03 leaves, the 03 leaves are dried if necessary and extracted with a suitable solvent. As the extraction solvent, 9 usually water or a mixture of water and alcohol is used. As the alcohol, methanol, ethanol, propatool, etc. are used. Its concentration is usually 2,
7 about 15% to about 60% is preferred. Extraction can be accelerated by heating during extraction or crushing the dried GS leaves to be extracted, but heating should be done within a temperature range that does not cause the active ingredients of the GS leaves to undergo thermal decomposition.1 Usually below 50°C. It will be done.

The extract thus obtained is filtered through a filter paper and then through a microfiltration membrane (MP membrane). MF membrane.

There is no particular restriction on the material as long as the membrane pore diameter is 100 μm or less, and membranes such as those shown in Table 1 below may be used.

(Margin below) deep red cellulose acetate type Nitrocellulose-based Aromatic polyamide system Aliphatic polyamide system Polybenzimidacylon series Polysulfone type Polyacrylonitrile type Polyvinylidene fluoride Polytetrafluoroethylene polyethylene polypropylene polycarbonate PVC polyvinyl alcohol *Composite membrane ○ ○ ○ ○ ○ Laminate made of films of various materials above wood What are the forms of the MF membrane and the reverse osmosis membrane (RO membrane) described below?

It may be of any type, such as a flat plate type, tube type, spiral type, or holofiber type. Using such an MP membrane, the pressurizing pressure is 1 to 10 kg f/cm2. Flow rate 4
By filtering under conditions of ~1120L/win and a temperature of IO ~30°C, the turbidity was removed and the product became transparent and amber in color.

Moreover, a filtrate with suppressed bitterness characteristic of GS can be obtained aseptically.

Next, the filtrate treated with the MP membrane in this way.

Treatment is performed using a reverse osmosis membrane (RO membrane). The material of the RQ film is not particularly limited as long as it has a NaCl rejection rate of 60% or more. For example, films as shown in Table 1 above may be used. An RO membrane with a NaCl rejection rate of less than 60% is undesirable because a significant amount of the active ingredient leaks to the permeate side during 'a contraction (see Comparative Example 1). As for the NaCl rejection rate of such RO membranes, the nominal value for each membrane is published by the manufacturer. However, since the definition and measurement method of NaCt rejection rate may differ depending on the manufacturer, in the present invention, RO
Let us define the NaCl rejection rate of the membrane as follows.

(Definition of NaCl rejection rate of RO membrane) A 0.15% NaCl aqueous solution with a pH of 6 to 7 is used as the feed solution. Flow rate 5L/+ein
Processed at. Here, the pressurizing pressure suitable for the type of RO membrane used is 1. For example, 1. NTI made by Nitto Denko Corporation? -7
10kgf for 29HF membrane and NTR-739HF membrane
/cm”, 30kgf/c for NTR-7197 membrane
It is m2. The NaCl concentration of 14 degrees in the feed solution, the NaCl concentration in the obtained concentrate, and the NaCl concentration of 11 degrees in the permeate are each measured, and the value calculated by the quadratic equation is defined as the NaCl rejection rate.

NaCl rejection rate (%) Using such an RO membrane, pressurization pressure of 1 to 50 kgf/
cm2. Flow fi l = 10, t/rs in,
By performing filtration at a temperature of lO to 30°C, the active ingredients are effectively concentrated without being thermally decomposed.

(Example) The invention is illustrated by the following examples.

In the experiment, an extraction solvent (distilled water to which a preservative (dehydroacetic acid) was added) in an amount 10 times its Mm was added to 100 g of dried leaves of O3, and the mixture was extracted at 40° C. for 16 hours with shaking.

The obtained extract was filtered through a filter paper, and then filtered through an NTF-5200 flat plate membrane (manufactured by Nitto Denko Corporation, membrane pore diameter: 0.2 μm), which is a nitrocellulose-based MP membrane. This il
a! When M was analyzed by HPLC, an OA peak was observed at a retention time of 21 minutes. Next, il! The liquid was subjected to a flow f
f1l.

/sin, pressurization pressure 5 kgf/am", and concentrated at 25° C. to obtain a 5-fold concentrated solution. This concentrated solution was again analyzed by HPLC.

When we investigated the peak area at a retention time of 21 minutes, it was approximately 4.3
It was found that the permeate was concentrated twice and the loss to the permeate side was about 15%. No peak considered to be a decomposition product of GA was observed.

Using 30% aqueous ethanol as the extraction solvent and a composite membrane type NTR-729HF flat plate membrane (manufactured by Nitto Denko Corporation + NaCl rejection rate 92%) as the RO membrane, the pressurizing pressure was 20 kgf/cm2. The extraction and concentration operations of the dried GS leaves were carried out in the same manner as in Example 1, except that the procedure was as follows. The resulting 5-fold concentrated solution was analyzed by HPLC.

It was found that the peak corresponding to GA with a retention time of 21 minutes was concentrated approximately 5.5 times. No peak considered to be a decomposition product of GA was observed.

Extraction of GS dried leaves was carried out according to Example 1, except that a composite membrane type NTR-73911F flat plate membrane (manufactured by Nitto Denko Corporation, NaCl rejection rate 95%) was used as the RO membrane. and concentration operation was performed. The obtained 5-fold concentrated liquid was HP
When analyzed by LC, the retention time corresponding to GA was 21.
It was found that the peak of 10 minutes was concentrated about 11.5 times. No peak considered to be a decomposition product of GA was observed. No peak considered to be a decomposition product of GA was observed.

Extraction of GS dried leaves was carried out according to the number of layers carried out, except that a composite membrane type NTR-7410 flat plate membrane (manufactured by Nitto Denko Corporation, NaCl rejection rate 15%) was used as the RO membrane. and concentration operation was performed. The obtained 5-fold concentrated solution was subjected to IPL
When analyzed using C, the peak with a retention time of 21 minutes corresponding to GA was approximately 2.8 times more concentrated than 7.

It was found that approximately 60% of the peak leaked to the permeate side and was lost due to this concentration operation. No peak considered to be a GA product was observed.

5a of GS leaf extract obtained according to Example 1 in a test tube
Dispense +1 at 60°C, 80°C or 94° respectively.
The mixture was heated at C for 1 hour 23 hours or 5 hours. after that
When this extract was analyzed by HPLC, it was confirmed that the peaks at retention times of 21 minutes and 26 minutes corresponding to OA were significantly reduced. The results are shown in FIGS. 1(A) and 1(B). FIG. 1(A) shows a decrease in peak area at a retention time of 21 minutes due to heat treatment, and FIG. 1(B) illustrates a decrease in peak area at a retention time of 26 minutes due to heat treatment. In the figure, the white circle mark (O) indicates the treatment at 60℃, the black triangle mark (mu) indicates the treatment at 80℃, and the black circle mark (・)
indicates treatment at 94°C.

As is clear from FIG. 1, the peak area decreases due to heat treatment at a temperature higher than 60°C, indicating that GA is decomposed.

(Effects of the Invention) As described above, the present invention provides a method for effectively concentrating the heat-labile active components of a GS leaf extract without decomposing them. By this method, it is possible to obtain a transparent OS active ingredient concentrate with suppressed bitterness characteristic of GS. This GS active ingredient concentrate has significant pharmacological effects and can be effectively used in pharmaceuticals, low-calorie foods, and the like.

4. of. Figures 1 (A) and (B) are graphs showing changes over time in the peak area of gymnemic acid when a Gymnema sylvestre leaf extract is heat-treated.

Figure 1 (A) Figure 1 (8) Heat treatment time (hr)

Claims (1)

[Claims] 1. Gymnema sylvestre (¥Gymnema¥¥Sy
A method for concentrating a Gymnema sylvestre leaf extract, which includes concentrating the leaf extract using a reverse osmosis membrane. 2. The method according to claim 1, wherein the extraction solvent is water or a mixture of water and alcohol. 3. The NaCl rejection rate of the reverse osmosis membrane exceeds 60%;
The method according to claim 1.