JP2011037800A - Blood glucose level elevation inhibitor and food material for preventing diabetes by using apios blossom - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substance exhibiting a health function in a human body by using blossoms which are waste materials in the production of apios, and a food raw material based on such the substance. <P>SOLUTION: The extract of apios blossom is prepared and fractionated by a column chromatographic means, and components are separated and purified by using radical scavenging activity and α-glucosidase inhibitory activity as indices. As a result, as a component having a maltase inhibitory effect, AFL60F28-1 is isolated and identified as (E)-3-(3, 4-dihydroxyphenyl)acrylic acid β-D-glucopyranosyl(caffeoyl β-D-glucopyranoside) or 2-O-[3-(3, 4-dihydroxyphenyl)acryloyl]-D-glucopyranose. As a result of administering an active fraction AFL60 containing the component to mice, the elevation inhibitory effect of blood sugar level is observed in normal mice as well as diabetes model mice. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a blood glucose level increase inhibitor using an Apios flower and a food material for diabetes prevention, and in particular, an increase in a blood glucose level using an Apios flower that can be obtained by effective use of a flower that is a waste in Apios production. The present invention relates to an inhibitory substance and a food material for diabetes prevention.

  Apios (aka Hodimo) is a leguminous creeping plant native to North America, and is said to have spread from Aomori Prefecture in Japan. In other words, it is thought that Apios was mixed in the seedling soil when the apple was introduced, and the cultivation in Japan originated from Aomori Prefecture both in seed and cultivation methods. What is currently handled as an agricultural product is Apios americana Medikus, and the spherical rhizome is edible.

  In the past, it was taken up by the media as a dream healthy crop based on the experiences of users, and Hoshikawa et al. Studied the cultivation method (K. Hoshikawa., Et al .: The growth of Apios (Apios americana Medikus ), a new crop, under field conditions. Jpn. J. Crop Sci., 64, 323-327, 1995.). However, various physiological actions such as nourishing and tonic effects are just a kind of tradition, and scientific basis was scarce.

  Therefore, the inventors of the present application have found that 7 to 11% of the antihypertensive effect and the effect of reducing triglycerides are given to the hypertensive rat (SHR). In a study conducted based on this result, an anti-hypertensive component of Apios was searched using angiotensin converting enzyme (ACE) inhibitory activity as an index, and an ACE inhibitory peptide was discovered and patented (Patent Document 1). In addition, Kuraishi Regional Promotion Corporation in Gonocho, one of the prefecture's production areas, is developing new products in cooperation with the inventors of the present application.

  In addition, about the potato part of Apios, the present inventors have already scientifically reported the physiological action (Non-patent Documents 1 and 2). In Apios cultivation, it is said that picking flowers that bloom in summer is one way to make good potatoes, and the picked flowers are currently discarded.

  On the other hand, according to the summary of the results of the 2006 National Health and Nutrition Survey (Ministry of Health, Labor and Welfare, Health Bureau, General Affairs Division, Lifestyle-related Disease Control Office) It is estimated that there are about 10.5 million people who cannot deny the possibility of diabetes, a total of about 18.7 million people, and 800,000 people who are strongly suspected of having diabetes compared to 2002 There was an increase of 2.5 million people who could not. Moreover, in 40-74 years old, one in two men and one in five women are considered to be highly suspected of metabolic syndrome (visceral fat syndrome) or its reserve group.

  Under such circumstances, the importance of primary prevention of lifestyle-related diseases by improving dietary habits has increased, and the public's health consciousness has increased. In addition, a specific medical checkup system was started in April 2008. Depending on the results of the medical checkup, guidance for improvement and reporting of the results are required, and a shift from treatment to prevention is being promoted as a measure to reduce medical expenses. Yes. Against this backdrop, interest in functional health foods as an aid to preventive medicine has increased, and the market size including foods for specified health use and so-called health foods approved by the Ministry of Health, Labor and Welfare is larger than the annual sales of over-the-counter drugs. It is over trillion yen, and the Biotechnology Strategic Chart estimates that it will exceed 3.2 trillion yen in 2010.

JP 2007-326790 A "Apios Acetic Acid / Enzyme Processed Product Production Method, Apios Derived Peptide, and Production Method Thereof"

K. Iwai., Et al .: Ingestion of Apios americana Medikus tuber suppresses blood pressure and improves plasma lipids in spontaneously hypertensive rats. Nutr. Res., 27, 218-224, 2007. Kunihisa Iwai, et al .: “Industry Promotion Model Using Agricultural and Fishery Products Produced by Prefectural Government” Results Report, 21 Aomori Industry Support Center, 2005.

  As mentioned above, in Apios cultivation, flowers are picked to make good potatoes, and they are discarded and their effective use is being sought. If this flower can be used effectively, both the effective use of resources and the reduction of waste production can be achieved. Furthermore, as described above, the present inventors have clarified a good health effect on the body, such as a blood pressure lowering action, for the physiological action of the Apios potato part. There is no particular technical disclosure document in the past.

  Therefore, the problem to be solved by the present invention is to provide a substance that can exert a health function in the human body by using a flower that is a waste in the production of Apios, and a food material based on such a substance.

  The inventors of the present application investigated the physiological action of polyphenols contained in Apios flowers and searched for physiologically active components that contribute to the prevention of lifestyle-related diseases that have been increasing in recent years. As the physiological action, the present inventors focused on α-glucosidase inhibitory activity that contributes to the prevention of diabetes, where the increase is particularly remarkable. Furthermore, an animal test was conducted to confirm the usefulness of physiological activity. As a result, it was found that Apios flowers have useful physiologically active ingredients, and the present invention has been completed. That is, the invention claimed in the present application, or at least the disclosed invention, as means for solving the above-described problems is as follows.

[1] A substance having an effect of suppressing an increase in blood glucose level using an Apios americana Medikus flower.
[2] A substance for suppressing an increase in blood glucose level using an Apios americana Medikus flower extract.
[3] A substance for suppressing an increase in blood glucose level, using a compound having an α-glucosidase inhibitory action, which is extracted from Apios americana Medikus flowers.
[4] A food material for preventing diabetes using the blood glucose level increase inhibitory substance according to [1].
[5] A food material for preventing diabetes using the substance for suppressing an increase in blood glucose level according to [2] or [3].

  Since the blood glucose level increase inhibitor and the food material for diabetes prevention using the Apios flower of the present invention are configured as described above, according to this, the flower which is waste in the production of Apios that has not been used conventionally is effectively used. Utilizing this, a food material having an α-glucosidase inhibitory action and an effect of suppressing an increase in blood glucose level can be obtained, and based on this, a food having such an action effect can be realized. Furthermore, waste production in Apios cultivation can also be reduced.

  The present invention demonstrates the usefulness of Apios flowers, broadens the potential for the development of new healthy food ingredients, and is therefore of great significance in helping to stop the disease from the increasing group of lifestyle-related diseases. It's deep. Conventionally, there are only a limited number of plant foods that can eat flowers, such as broccoli and chrysanthemums. That is, according to the present invention, a new food resource that contributes to the prevention of lifestyle-related diseases can be provided and developed by the α-glucosidase inhibitory activity revealed in Apios flowers.

It is a photograph of Apios flowers. It is a photograph of a dried Apios flower. It is a flowchart which shows the fractionation method of an active fraction. It is a semi-preparative HPLC chromatogram of AFL40 and AFL60. It is a HPLC chromatogram which shows the result which further refine | purified AFL60F28. It is a chromatogram which shows the result of having analyzed AFL60F28-1 by LC / MS / MS. It is a graph showing the results of ¹ H-NMR analysis of AFL60F28-1. It is a graph which shows the ¹³ C-NMR analysis result of AFL60F28-1. It is a graph which shows the DEPT analysis result of AFL60F28-1. It is structural formula which shows the chemical structure of AFL60F28-1. It is structural formula which shows the chemical structure of AFL60F28-1. It is a graph which shows plasma glucose level transition after a single oral administration of AFL60 and maltose simultaneously to a normal mouse. It is a graph which shows plasma glucose level transition after a single oral administration of AFL60 and maltose simultaneously to a diabetes model mouse.

The present invention will be described in detail.
1A and 1B are photographs of Apios flowers and dried Apios flowers, respectively.
The “equipment of suppressing blood glucose level increase using Apios americana Medikus flower” of the present invention refers broadly to those having an effect of suppressing blood glucose level increase by using Apios flower. In other words, regardless of how the Apios flower is processed or not, whether it is a processing form or a usage form, any use of the Apios flower falls under this invention.

  Furthermore, "things" with such effects include not only irregular shapes such as powder, granules, liquids and fluids, but also those with certain forms, and conversely, substance levels such as chemical levels. The thing of this is also included widely. Therefore, an extract from Apios (Apianas americana medikus) flower and having an effect of suppressing an increase in blood glucose level is naturally within the scope of the present invention.

  In addition, the food material for diabetes prevention using such “blood sugar level increase inhibitory effect ingredient” is not limited in its kind, form, etc., as long as it uses the blood sugar level increase inhibitory effect ingredient of the present invention. All kinds and forms of food materials fall under the present invention.

  In particular, the “suppressing substance for increasing blood glucose level using Apios americana Medikus flower extract” of the present invention uses a compound having an α-glucosidase inhibitory action extracted from Apios flowers as described later in Examples. It was a substance that suppresses blood sugar levels.

  In addition, the food material for diabetes prevention using such a “blood sugar level increase-inhibiting substance” is not limited in its type, form, etc., as long as it is a substance that has the effect of suppressing blood sugar level increase according to the present invention. Types and forms of food materials fall under the present invention.

Hereinafter, the present invention will be described in more detail with reference to research progress that has led to the completion of the present invention, but the present invention is not limited to such examples.
Prior to detailed description of the examples, some terms in the course of the study will be explained in part, including the relationship with this study.

<Α-Glucosidase inhibitory activity>
Most of the carbohydrates ingested by humans are polysaccharide starches, but eventually they are broken down into monosaccharides by several types of α-glucosidase (disaccharide hydrolase) present in the brush border membrane of small intestinal mucosal epithelial cells. Absorbed from the epithelium. In diabetic patients, these enzyme activities in the small intestine are enhanced, and it is considered that the rapid increase in blood glucose after meal is associated with an increase in enzyme activity along with insufficient insulin secretion and insulin resistance. In particular, diet therapy is fundamental to improving hyperglycemia in patients with type 2 diabetes, but α-glucosidase inhibitors have been developed from the viewpoint of blood glucose control by delaying digestion and absorption of carbohydrates (W. Puls, U. Keup: Influence of an α-amylase inhibitor (Bay 7791) on blood glucose serum insulin and NEFA in starch loading tests in rats dog and man. Diabetologia, 9, 97-101, 1973.).

Recently, research on searching for α-glucosidase-inhibiting ingredients from food materials has been actively conducted due to its strong relationship with meals and great merit for development as food for specified health use (T. Matsui, et al .: In vitro survey of α-glucosidase inhibitory food components. Biosci. Biotechnol. Biochem., 60, 2019-2022, 1996.), Banaba (Yuko Suzuki, et al.) Postprandial blood glucose elevation-inhibiting action and its mode of action in rats. Journal of Japanese Society of Nutrition and Food Science. 54, 131-137, 2001.), Mulberry Leaf (Yoshihiro Kojima: Health Function of Mulberry Leaf, Food and Development, 37 (10), 54-56, 2002.), Tamogitake (Fujino Masayuki, Whatmoaki Akira: Tamogitake hot water extract suppresses blood glucose level in type II diabetes model mice. Journal of Japanese Society for Food Science and Technology, 45, 618-623, 1998.) Has been.

  In particular, a component having a structure similar to glucose was extracted from mulberry leaves and identified as 1-deoxynojirimycin (DNJ) (N. Peyrieras, et al .: Effects of the glucosidase inhibitors nojirimycin and deoxynojirimycin on the biosynthesis of membrane and secretory. glycoproteins. EMBO J., 2, 823-832, 1983., etc.). In this way, α-glucosidase inhibitory action is beneficial for the suppression and improvement of hyperglycemia, and many food developments and researches aimed at diabetes prevention inhibit and delay carbohydrate degradation and absorption to improve hyperglycemia. What you do is mainstream.

<Polyphenol>
Polyphenols have the function of helping the generation and activation of plant cells. Since its effectiveness is based on an antioxidant action, it is related to various biological adjustment functions such as arteriosclerosis, diabetes, prevention of cancer and the like, and aging suppression. As the polyphenols in Apios flowers, anthocyanins and the like have been inferred by the present inventor (Kunihisa Iwai, et al .: “Industrial Promotion Model Using Agricultural and Fishery Products Produced by the Prefectural Government” Result report, 21 Aomori Industrial Support Center) , 2005), details are not elucidated.

<A Research Method>
In order to increase the utility value of Apios flowers, we searched for beneficial physiological activities of Apios flowers, especially α-glucosidase inhibitory activity, antioxidant activity, etc., and elucidated their active components (determined structure).
<A-1. Sample preparation>
Apios flowers collected in August in the Kuraishi area of Gonomachi were dried with warm air at 50-60 ° C. This was homogenized in formic acid, trifluoroacetic acid (TFA) and 1% formic acid-containing methanol (formic acid / MeOH), stirred and extracted, and the supernatant obtained by centrifugation was concentrated to dryness, freeze-dried and crudely extracted. A polyphenol concentration by the Folin-Denis method (Gao X., et al .: J. Sci. Food Agric., 80, 2021-2027, 2000. The same applies below), DPPH radical scavenging activity (Tatsuo Suda) : Antioxidant function, spectroscopic antioxidative function evaluation. Food function research method, Kazuaki Shinohara et al., Pp.218-220, Mitsuru, 2000. The same applies to this), α-glucosidase (maltase) inhibitory activity (Suzuki) Yuko, et al .: Banana (Lagerstroemia speciosa L.) leaf extract suppresses postprandial blood glucose elevation in rats and its mode of action. Journal of Japanese Society of Nutrition and Food Science. 54, 131-137, 2001. The optimal extraction method was determined.

<A-2. Measurement of physiological activity>
In the measurement of DPPH radical scavenging activity, a sample was dissolved and diluted with ethanol, a DPPH solution was added and mixed, and the absorbance at 520 nm was measured. A calibration curve was prepared from the absorbance of Trolox as a standard substance, and the radical scavenging activity per 1 μg of the sample was calculated as the equivalent of Trolox.

  For the measurement of maltase inhibitory activity, maltose (substrate) was mixed with a sample prepared with maleic acid buffer (pH 6.0) and pre-incubated. To this mixture, a crude enzyme solution derived from rat small intestine powder was added and mixed, and incubated at 37 ° C. Sampling with time, the enzyme reaction rate was determined from the amount of glucose produced measured by the murotase-GOD method, the reaction rate of the enzyme + substrate alone was taken as 100%, and the enzyme activity inhibition rate at the time of sample addition was calculated. From the relationship between the sample concentration and the inhibition rate, the 50% inhibition concentration (IC50) was calculated as the inhibitory activity.

<A-3. Large-scale preparation of Apios flower active fraction>
A large amount of Apios flower formic acid / MeOH extract was prepared and fractionated by Sephadex LH-20 column chromatography (37 × 980 mm). 2 g of the extract was loaded in one treatment, and 450 mL of a 1% formic acid / MeOH mixed solution having an MeOH content of 0, 20, 40, 60, 99 and 100% was flowed at a flow rate of 2 mL / min. The eluate (AFL0, AFL20, AFL40, AFL60, AFL99, AFL100) was collected, concentrated and lyophilized, and this treatment was repeated to prepare a large amount of the active fraction. The total polyphenol concentration, DPPH radical scavenging activity and maltase inhibitory activity of all fractions were measured to determine the active fraction.
FIG. 2 is a flowchart showing the fractionation method of the active fraction.

<A-4. Analysis of Apios Flower Polyphenol>
AFL0, AFL20, AFL40, AFL60, AFL99 and AFL100 fractionated with Sephadex LH-20 were analyzed by high performance liquid chromatography-photodiode array detection (HPLC-PDA), and polyphenols contained in each fraction were analyzed. . The analysis system was Waters 2695 (Waters), the column was Inertsil ODS-3 (particle size 5 μm, 4.6 × 150 mm), and A solution 10% formic acid and B solution acetonitrile were used as the mobile phase at a column temperature of 40 ° C. The flow rate was 1.0 mL / min with a linear gradient changing from 0 to 70% in solution B in 35 minutes. The analytical injection volume was 10 μL, and it was detected with a 2998 PDA detector (Waters) in the wavelength range of 200 to 800 nm.

<A-5. Separation of major polyphenols, separation and purification of active ingredients>
AFL60 (maltase inhibition fraction) was subjected to preparative HPLC, and the main peak was fractionated. Preparative HPLC uses W600 (Waters) for the pump and injector, Inertsil ODS-3 (20 × 300 mm) for the column, A solution 10% formic acid and B solution acetonitrile for the mobile phase, and a column temperature of 40 ° C. The elution was performed at a flow rate of 5.0 mL / min under a linear gradient condition in which the concentration was changed from 0% to 70% in 0 to 70 minutes (liquid B was 100% in 70 to 90 minutes and then equilibrated to initial conditions). The injection amount of AFL60 was 500 μL, and detection was performed at a wavelength of 280 nm. Using a fraction collector DC-1500 manufactured by EYELA, peaks were fractionated at intervals of 1 minute in a fractionation section of 10 to 54 minutes. The fractionated active polyphenol was analyzed and purified by HPLC-PDA. The apparatus, column, and mobile phase were the same as the analysis conditions described above, and the gradient condition of the mobile phase was changed to a linear gradient that changed from 0 to 35% in 0 to 60 minutes.

<A-6. Structure determination of active ingredient>
The structure was determined by nuclear magnetic resonance (NMR) and liquid chromatography mass spectrometry (LC / MS / MS) to identify the structure of the active ingredient.

<A-7. Physiological effects of Apios flower active fraction>
In order to prepare a large amount of Apios flower active fraction AFL60 and examine physiological effects, a glucose tolerance test was conducted in which maltose was administered. As animals, male ddY mice (10 weeks old) as normal mice and male KK-Ay mice (10 weeks old) as diabetic model mice were mixed, and AFL60 and maltose were mixed and administered orally once under fasting for 20 hours. did. The doses of AFL60 were suspended in 0.5% carboxymethylcellulose as 0,62.5,125 and 250 mg / kg, and the dose of maltose was 0.6 g / kg. At 0, 0.5, 1 and 2 hours after administration, blood was collected from the orbit using a heparinized plastic capillary tube, and the blood was immediately centrifuged with a hematocrit centrifuge (3220, Kubota) (12,000 rpm × 2 minutes). Plasma was collected. The solution was appropriately diluted with a 0.15 M NaCl solution, and the plasma glucose concentration was measured with Glucose CII-Test Wako (Wako Pure Chemical Industries).

<B Results and discussion>
<B-1. Large-scale preparation of Apios flower active fraction>
In the extraction of Apios flowers, 1% formic acid / MeOH extraction is superior in total polyphenol concentration, DPPH radical scavenging activity and α-glucosidase inhibitory activity compared to formic acid and TFA extraction. / MeOH extraction was found to be suitable.
Table 1 shows the yield, total polyphenol concentration, DPPH radical scavenging activity and α-glucosidase inhibitory activity when Apios flower formic acid / MeOH extract was fractionated by Sephadex LH-20 column chromatography.

  The fractionated 70% was collected in AFL0, but this contained almost no polyphenol, neither DPPH radical scavenging activity nor glucosidase inhibitory activity was observed, suggesting that most were carbohydrates. AFL40 had the highest total polyphenol concentration, but AFL60 had the strongest DPPH radical scavenging activity and glucosidase inhibitory activity. Therefore, AFL60 was used for sorting for active ingredient identification.

<B-2. Elucidation of active ingredients of Apios flowers>
1) Fractionation of main polyphenols by using semi-preparative reverse phase column Fractionation by semi-preparative HPLC was performed under linear gradient elution conditions, and a large amount of peaks were separated from AFL60. Using a fraction collector, peak fractionation was performed at 1 minute intervals with a retention time of 10 to 54 minutes.
FIG. 3 is a semi-preparative HPLC chromatogram of AFL40 and AFL60. As a result, as shown in the figure, very large peaks were obtained at 33 minutes and 36 minutes from AFL60. Also, when AFL40 was treated in the same manner, major peaks were obtained at 34, 37 and 39 minutes.

  When the maltase inhibitory activity of these fractionated peaks was measured, the strong inhibitory activity was that of Fr. 25, Fr. 28 and Fr. 29, and the maltase inhibition rate in these was 50% or more. Fr. 25 has a low yield, so Fr. 28 and Fr. 29 was collected as the active polyphenol and further purified. AFL40 is also Fr. 29 and Fr. Since 30 were considered similar to these, they were collected in the same way.

2) Separation and purification of active polyphenols Fr. When 28 (AFL60F28) was analyzed again by HPLC, 4 to 5 peaks were mixed. These were suggested to be polyphenol compounds.
Accordingly, as a result of further purification of AFL60F28 by changing the HPLC conditions, main peaks # 1 to # 5 were obtained. These were one type of component having an absorption maximum at 320 nm, two types of components having an absorption maximum at 280 nm, and two types of components having an absorption maximum at 525 nm.
FIG. 4 is an HPLC chromatogram showing the results of further purification of AFL60F28.

  Table 2 shows the maltase inhibitory activity of these peaks # 1 to # 5. Each yield was 0.4-0.8 mg, corresponding to 3-6% of AFL60F28. Peaks # 4 and # 5 were shown to be anthocyanins, but the inhibition rate was as low as 30% or less, and # 1 (AFL60F28-1) showed the strongest inhibition, and this component had an absorption maximum at 330 nm. It was suggested that this is a polyphenol compound.

FIG. 5 is a chromatogram showing the results of analyzing AFL60F28-1 by LC / MS / MS. As a result, AFL60F28-1 was estimated to have a molecular weight of 342. Also,
FIG. 6 is a graph showing the results of ¹ H-NMR analysis of AFL60F28-1.
FIG. 7 is a graph showing the result of ¹³ C-NMR analysis of AFL60F28-1, and FIG. 8 is a graph showing the result of DEPT analysis of AFL60F28-1.

From the above analysis results, AFL60F28-1
(E) -3- (3,4-dihydroxyphenyl) acrylate β-D-glucopyranosyl (caffeoyl β-D-glucopyranoside) having a molecular formula of C ₁₅ H ₁₈ O ₉ , or
It was shown to be any of 2-O- [3- (3,4-dihydroxyphenyl) acryloyl] -D-glucopyranose.
9A and 9B show these structural formulas.

<B-3. Physiological effects of Apios flower active fraction>
A load test was conducted in which AFL60 was mixed with maltose as an Apios flower active fraction and administered to mice once orally.
FIG. 10 is a graph showing changes in plasma glucose concentration after a single oral administration of AFL60 and maltose simultaneously to normal mice. The dose of maltose is 0.6 g / kg, and the data show the mean value ± standard deviation of 5 animals. As shown in the figure, when the male ddY mouse, which is a normal mouse, was loaded, the blood glucose level at 0.5 hours after administration was increased to 2.5 times the fasting blood glucose level by administration of maltose (Mal) alone. On the other hand, when AFL60 was mixed and loaded, the increase in blood glucose level was suppressed to 2 times or less. Although there was no statistically significant difference, this suppression was seen not only at 0.5 hours after administration but also at 1 hour. A dose dependency was also observed. Therefore, it was shown that Apios flowers have an inhibitory effect on the blood glucose level of normal mice.

A similar study was performed on diabetes model KK-Ay mice.
FIG. 11 is a graph showing changes in plasma glucose concentration after a single oral administration of AFL60 and maltose simultaneously to a diabetes model mouse. The dose of maltose is 0.6 g / kg, and the data show the mean value ± standard deviation of 5 animals. As a result, as shown in the figure, the blood glucose level reached its maximum 1 hour after maltose administration, and the level reached 2.7 times the fasting blood glucose level. Compared to ddY, the blood glucose level decreased slowly and showed a blood glucose level transition specific to the diabetes model. When AFL60 was administered, maltose alone and blood glucose level were not different at 0.5 hours, but showed a lower blood sugar level transition than maltose alone after 1 hour, indicating a tendency to suppress or suppress an increase in blood glucose level. It was done.

  From these results, it was shown that AFL60 has an effect of suppressing an increase in blood sugar. In diabetic model mice, a higher effect was observed at a lower dose. That is, it was shown that a sufficient increase in blood sugar can be obtained by using a small amount. On the contrary, when the dose is higher than necessary, a mechanism may be considered in which components contained in AFL60 cause some change in the digestive tract, leading to absorption as a carbohydrate and an increase in blood glucose level. Although such a phenomenon was not observed in normal mice, it is considered that a difference in biological functions regarding carbohydrate absorption and glycoside degradation between ddY mice and KK-Ay mice is involved.

  As described above, in the present invention, bioactivity was searched and active ingredients were identified for the purpose of high added value and effective use of conventionally discarded Apios flowers. That is, an Apios flower extract was prepared, fractionated by column chromatography, and components were separated and purified using radical scavenging activity and α-glucosidase inhibitory activity as indicators. As a result, AFL60F28-1 was isolated as a component having an inhibitory action on maltase (a kind of α-glucosidase), which was obtained from (E) -3- (3,4-dihydroxyphenyl) acrylate β-D-glucopyranosyl (cafe). Oil β-D-glucopyranoside), or 2-O- [3- (3,4-dihydroxyphenyl) acryloyl] -D-glucopyranose. It was first demonstrated by the present invention that these compounds have an α-glucosidase inhibitory action.

Furthermore, as a result of administering an active fraction AFL60 containing this component to mice, an effect of suppressing an increase in blood glucose level was observed in normal mice and diabetic model mice. From these results, it became clear that AFL60F28-1, AFL60 fraction containing AFL60F28-1 and Apios flower are useful as a new healthy food material that contributes to diabetes prevention. The importance of primary prevention of lifestyle-related diseases by improving dietary habits has increased, and the significance of the present invention, which is the basis for the development of food ingredients and foods that have the effect of suppressing the increase in blood sugar levels, is greatly significant in a situation where the public's health consciousness is increasing. It is an invention with high industrial applicability.

Claims (5)

There is an effect of suppressing the increase in blood glucose level using Apios (Apianas americana Medikus) flowers. A substance for suppressing an increase in blood glucose level, which uses an Apios americana Medikus flower extract. A substance for suppressing an increase in blood glucose level using a compound having an α-glucosidase inhibitory action, which is extracted from an Apios americana Medikus flower. A food material for diabetes prevention using the blood glucose level increase inhibitory substance according to claim 1. A food material for diabetes prevention using the blood sugar level increase-suppressing substance according to claim 2 or 3.