JPH0426627A - Insulin secretagogue derived from gymnema sylvestre - Google Patents

Abstract

PURPOSE:To obtain an insulin secretagogue useful for a curing agent to a patient of hyperglycemia or ketoacidosis, etc., instead of insulin containing an insulin secretion-accelerating substance collected from Gymnema sylvestre with isolation as an active ingredient. CONSTITUTION:An insulin secretion-accelerating substance collected from Gymnema sylvestre with isolation is contained in the aimed agent as an active ingredient. Said accelerating substance is obtained by extracting Gymnema sylvestre with water, alcohol or water-containing alcohol, removing precipitating component in an aqueous solution of pH1-4, neutralizing by alkali such as caustic soda and purifying using an ion exchange resin. In isolation and collection of said accelerating substance, an extracting solution is used in dividing to 1-several times in usually 5-20 pts.wt. to 1 pt.wt. dried Gymnema sylvestre.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an insulin secretagogue active substance derived from Gymnema sylvestre (a species of Asclepiadaceae), a method for separating and collecting the same, a method for purifying the same, and a method for using the same as an active ingredient. This invention relates to an insulin secretion promoter.

More specifically, the present invention provides Gymnema sylvestre water,
From extracts with alcohol or hydroalcohol, pH
A method for separating and collecting an insulin secretagogue active substance, which comprises separating and collecting the insulin secretagogue active substance after removing the components precipitated in the aqueous solution of 1 to 4, and purification of the insulin secretagogue active substance using an ion exchange resin. The present invention provides an insulin secretagogue, which contains as an active ingredient a novel insulin secretagogue active substance derived from Gymnema sylvestre that has been isolated, collected, and purified using a method.

The novel insulin secretagogue of the present invention is useful for various patients treated by administration of insulin, such as hyperglycemia, hyperglycemia, etc.
It is expected to have a wide range of uses as a therapeutic agent in place of insulin for patients with ketoacidosis, schizophrenia, etc.

[Conventional technology]

Gymnema 5ylves
tre) is a tropical and subtropical plant belonging to the Asclepiadaceae family native to India, and is a gymnemic acid that suppresses the absorption of glucose in the small intestine and suppresses the rise in blood sugar level after sugar loading. Because it contains medicinal ingredients, the leaves of this plant can be roasted in the air and served as bancha, or the components in the leaves can be separated and added to foods to suppress the rise in blood sugar levels. It is known to reduce the calorie content of meals (Japanese Patent Application Laid-Open Nos. 61-5023 and 6485058).

Academic literature [J.
Agr, Food Chem, 17.704 (19
69), ], and the separation of their main components is described in academic literature [J, Pharm, Sci,
59.622.629 (1970), ].

The present inventors first noticed that Gymnema sylvestre extract has the effect of suppressing sweetness and exhibiting a strong bitter taste, which is problematic as a food additive.
We discovered that by removing the components that precipitate in the aqueous solution of No. 4, this taste suppressing effect could be reduced without impairing the blood sugar level rise suppressing effect, and we filed a patent application (Japanese Patent Application Laid-Open No. 2002-79
No. 955).

However, until now, it has not been known at all that an insulin secretagogue active substance exists in Gymnema sylvestre extract.

[Problem to be solved by the invention]

The present inventors have conducted various studies with the aim of collecting new pharmacologically active substances from the Gymnema sylvestre plant.

[Means for solving the invention]

The present invention is based on the success in separating and collecting a substance having excellent insulin secretagogue activity from an extract of the Gymnema sylvestre plant.

The insulin secretion promoting active substance of the present invention is obtained by removing components that precipitate in an aqueous solution of pH 1 to 4 from the extract of G. mnema sylvestre with water, alcohol, or hydrous alcohol, and then neutralizing it with an alkali such as caustic soda. Purified using ion exchange resin.

In separating and collecting the insulin secretion-promoting active substance of the present invention, the extraction solvent is 1 dry weight of Gymnema sylvestre.
It is usually used once or divided into several times at a ratio of 5 to 20 parts per part.

The appropriate extraction temperature is room temperature to 100°C for water extraction, and room temperature to 80°C for alcohol or hydrous alcohol. The extraction time and number of extractions vary depending on the type of solvent, temperature, stirring conditions, etc. However, it is usually sufficient to repeat the extraction three times for three hours each time.

As a method for removing components that precipitate in an aqueous solution with a pH of 1 to 4 from an extract, in the case of water extraction, the extract is directly diluted with hydrochloric acid, sulfuric acid, etc. to a pH of 1 to 4, preferably 1.5 to 2.
5, the formed precipitate can be removed by filtration or centrifugation, and when extracted with alcohol or hydrous alcohol, the alcohol is distilled off in advance, the extract is made into an aqueous solution with a concentration of about 2 to 10 parts, and then water is added. As in the case of extraction, the pH can be adjusted by adding an acid such as hydrochloric acid to generate and remove a precipitate. As a method for separating and collecting or purifying the insulin secretion promoting active substance from the extract from which the precipitate generated in the aqueous solution of p111-4 has been removed, adsorption removal of impurities using an adsorbent is utilized.

Strongly acidic ion exchange resin (SK IB) is used as an adsorbent.
and a strongly basic ion exchange resin (SAIOAX, both manufactured by Mitsubishi Kasei Kin).

As mentioned above, the insulin secretion promoting active substance of the present invention has very low toxicity and can be used as an insulin secretion promoting agent (medicine), and can be formulated into conventional dosage forms such as oral preparations and injections. For patients requiring insulin administration, usually 0.000 mg/kg body weight. O1~0
．． When administered at a rate of about 2 g, it is expected to be effective in treating hyperglycemia, ketoacidosis, schizophrenia, etc.

EXAMPLES The embodiments of the present invention will be specifically described below with reference to Examples.

Example 1 20 g of dried leaves of Gymnema sylvesta were placed in 240 m (!) of 30% ethanol, extracted at 30°C for 2 hours (while stirring or standing still), and then filtered to obtain an extract. The extraction was repeated two more times under similar conditions using fresh 30% ethanol.

A total of three extracts were combined, the ethanol was evaporated, the solution was concentrated under reduced pressure to a volume of about 360 mJ', and hydrochloric acid was added at room temperature to adjust the pH of the aqueous solution to 1.5 for precipitation. After removing the precipitate by centrifugation and neutralizing the supernatant with caustic soda (cation or anion), 100 g of exchange resins SK I B and 5A10A (both manufactured by Mitsubishi Kasei Metal Co., Ltd.) were charged. It was passed through a column to adsorb and remove impurities, and the effluent was collected, concentrated under reduced pressure, and then lyophilized to obtain 1.0 g of a white powder, which was used as a standard product of the insulin secretion promoting active substance of the present invention. .

〔Effect of the invention〕

The novel insulin secretagogue active substance of the present invention (hereinafter referred to as r
RGSJ) is expected to find wide use as a novel therapeutic agent in place of insulin for various patients suffering from hyperglycemia, ketoacidosis, schizophrenia, etc., who are treated by insulin administration.

Test examples will be shown below to specifically explain the effect as an insulin secretagogue.

Test Example 1 (Therapeutic Effect Test) Ten 8-week-old Wistar rats (male) were divided into two groups of five rats each, one group was given 1 g of glucose/kg rat body weight, and the other group was given Ig glucose. +O, Ig RG
S/kg body weight was orally administered using a sonde, and blood was collected by decapitation at 15, 30, 60, 90, and 120 minutes after administration, and the concentrations of insulin and glucose in the blood were measured. Insulin concentration was measured using EIA Test Insulin ■ (BMY) (manufactured by Boehringer Mannheim Yamanouchi Company), and glucose concentration was measured using New Blood Sugar Test (manufactured by Boehringer Mannheim Yamanouchi Company).

The measured values (increase/decrease values) of insulin concentration are shown in Table 1.
Measured values (increase/decrease values) of glucose concentration are shown in Table 2.

In addition, the measured values in the table are shown as the average value of 5 animals.

Table 1 (Margins below this page) Table 1 As is clear from the results in Tables 1 and 2 above, RG
S administration significantly promoted insulin secretion and suppressed the rise in blood sugar levels.

Test Example 2 (Preventive Effect Test) Seven-week-old Wistar rats (male) were kept in metabolic cages for six weeks, divided into an RGS administration group and a non-administration group. R
GS administration was performed by adding 0.5% RGS to the feed (equivalent to 1/100 of the amount of sugar in the feed).
Water and feed were available ad libitum. After 6 weeks of rearing, each rat in both groups was orally administered 1 g of glucose/kg of rat body weight using a sonde, and 45 minutes after administration, the blood was collected by decapitation and the concentration of insulin and glucose in the blood was measured. (
increase/decrease value).

The results of this test are shown in Table 3.

The results in the table are the average values of 5 animals per group.

As shown in the results in Table 3, insulin secretion was significantly promoted in the rats in the group to which RGS was prophylactically administered, and the increase in blood sugar concentration was suppressed.

Claims (1)

[Scope of Claims] 1. An insulin secretagogue characterized by containing an insulin secretagogue active substance isolated and collected from Gymnema sylvestre as an active ingredient. 2. Obtain an extract from Gymnema sylvestre using water, alcohol, or hydroalcohol as an extraction solvent, and after removing components that precipitate in an aqueous solution with a pH of 1 to 4, separate and collect the insulin secretion promoting active substance. A method for separating and collecting an insulin secretion promoting active substance, characterized by: 3. A method for purifying an insulin secretagogue active substance, which comprises contacting an aqueous solution of a crude insulin secretagogue active substance derived from Gymnema sylvestre with an ion exchange resin to remove adsorbed impurities.