Diabetes appears to be one of the most frequent noncommunicable diseases in the world. A permanent growth in the incidence of diabetes can be observed and according to the International Diabetes Federation (IDF) the year 2030 will mark the increase in the number of diabetics to 439 mln worldwide. Type 2 diabetes accounts for about 90% of all diabetes incidence. Nutrition model modification not only features the basic element in type 2 diabetes treatment but also constitutes the fundamental factor influencing a morbidity rate decrease. Leguminous plants are a key factor in the diabetic diet; plants such as pulses or soybeans are nutritious products valued highly in nutrition. These legumes are high in the content of wholesome protein and contain large amounts of soluble alimentary fiber fractions, polyunsaturated fatty acids, vitamins and minerals, and bioactive substances with antioxidant, anti-inflammatory, and anticancer activity. They are distinguished by the high amount of bioactive compounds that may interfere with the metabolism of glucose. The most significant bioactive compounds displaying antidiabetic activity in leguminous plants are as follows: genistein and daidzein, alpha-amylase inhibitors, and alpha-glucosidase inhibitors.
Diabetes appears to be one of the most frequent noncommunicable diseases in the world. A permanent growth in the incidence of diabetes can be observed and according to the International Diabetes Federation (IDF) the year 2030 will mark the increase in the number of diabetics to 439 mln worldwide. In Europe, the highest morbidity rates are observed in Germany (8.9% population), Spain (8.7%), and Belgium (8.0%) and the lowest rates in Great Britain (4.9%) and Sweden (5.2%). The biggest populations of diabetics worldwide, however, are to be found in India (51 mln), China (43 mln), and the USA (27 mln).
Type 2 diabetes accounts for about 90% of all diabetes incidence. It is estimated that about 50% of diabetics remain undiagnosed [
Leguminous plants, for example, pulses (dry beans, chickpeas, lentils, and peas) and oil seed (soybeans), are a key factor in the diabetic diet. These plants are nutritious products valued highly in nutrition. This specific group provides wholesome products of vegetable protein whose volume ranges from 20% in beans and peas up to 38–40% in soya beans. These proteins contain a large amount of lysine, especially in beans, which is the reason they are regarded as wholesome. Protein nutritive value is reduced by subdued sensitivity to proteolysis, low contents of sulphur amino acids, and the presence of nonprotein substances such as phytic acid and tannic acid and nonphysiological proteins (lactinine, protease inhibitors). The legumes are known to contain large amount of soluble alimentary fiber fractions (4–6%), polyunsaturated fatty acids (18% in soya bean), B group vitamins, and minerals (phosphorus, potassium, calcium, magnesium, iron, zinc, and copper). They are described as possessing a low glycaemia index (<50) and they are alkalogenic products, which is especially vital in acid-alkaline balance maintenance in organisms [ carbohydrate digestion inhibition and the suppression of glucose absorption in the intestine, stimulation of insulin secretion from pancreatic insulin receptor activation [
Legume intake worldwide differs depending on the region. The highest intakes are registered in South America (10.7 kg/person annually), Africa (9.8 kg/person annually), and Asia (5.9 kg/person annually) [
The most crucial bioactive compounds displaying antidiabetic activity in leguminous plants are as follows: genistein and daidzein, alpha-amylase inhibitors, alpha-glucosidase inhibitors.
Genistein and daidzein are natural estrogens found in soya beans and soya derivative products. Their similarity to estrogens enables binding to receptors in human cells and in choriocarcinoma cell lines as well (BeWo and Jeg3) [
Equol is a metabolite of soy isoflavones—daidzin and daidzein. It is produced by intestinal bacteria but not in all people. The term equol-producers identifies those individuals who can produce equol in response to consumption of soy isoflavones. There is also an established hypothesis that equol-producers consuming soy diet had greater health benefits than equol-nonproducers [
The alpha-amylases inhibitors are, inter alia, compounds which suppress carbohydrate absorption through inhibiting enzymes responsible for starch digestion. Alpha-amylase inhibitors are found in legumes, fruit, green and black teas, wheat, and rice. Three isoforms of alpha-amylase inhibitors are found in legumes: alpha-amylase inhibitor isoform 1 (Alpha- AI1), alpha-amylase inhibitor isoform 2 (Alpha-A12), and alpha-amylase inhibitor isoform like (Alpha-AIL). The alpha-AI1 isoform displays activity in humans. Phaseolamin is the generic name for the common white bean extract containing alpha-amylase inhibitors. Alpha-AI1 is found in germs and seeds and cannot be found in other plant parts. Alpha-AI1 synthesis occurs at the same time as the phaseoline and phytohaemagglutinin (PHA), stored in vacuole. These are typical lectines, synthesised in rough endoplasmic reticulum and modified through Golgi apparatus in the form of signal peptide removal and N-glycosylation. They possess homologous amino acid sequences, from 50 to 90% [
Alpha-AI1 is detected 17 days after pollination in seed axes and cotyledons. Regular growth happens up till the 28th day. The level of Alpha-AI1 decreases slightly during the drying process [
The antidiabetic effect of the active compounds from legumes in research conducted in 2004–2014.
Authors | Type of study | Bioactive compounds | Glycaemia | Insulin | Body weight | Food intake | Other activities |
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Udani et al., 2004 [ |
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1500 mg water extract of a common white bean/day | — | — | ↓BMI | — | ↓Triglycerides level |
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Udani and Singh, 2007 [ |
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1000 mg fractionated white bean extract/day | — | — | ↓BMI | — | — |
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Celleno et al., |
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445 mg Phase 2 + 0.5 mg of chromium picolinate | — | — | ↓BMI | — |
↓Body weight |
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Maruyama et al., |
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Azuki juice 150 g * 5/day | — | — | ↓BMI | — | ↓Triglycerides level |
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Maruyama et al., |
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100 mg Azuki bean extract | — | — | — | — | ↓Activity alpha-glucosidase by 32.6% |
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Yao et al., |
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Vitexin and isovitexin |
↓Blood glucose level | ↑Insulin immunoreactivity | — | — | ↓Plasma C-peptide, ↓Glucagon, ↓total cholesterol, ↓Triglycerides, ↓BUN |
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Choi et al., |
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Genistein and daidzein |
↓Glucose level in blood | ↑Insulin production | — | — | ↓Triglycerides gradient in liver |
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Kim et al., |
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5 g genistein/100 g diet | — | ↑Insulin production |
— | — | — |
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Cederroth et al., |
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198 ppm daidzein and 286 ppm genistein/day | — | ↑Insulin sensitivity | — | — |
↓Lipid contents in adipocytes, ↑Phosphorylation of AMPK and acetyl-CoA carboxylase (ACC), ↑Expression of (PPR-l |
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Fu and Liu, 2009 [ |
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Genistein | — | ↑Glucose-stimulated insulin secretion | — | — | — |
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Vinson et al., |
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Phase 2 |
↓Blood glucose level | — | — | — | — |
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Udani et al., |
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Phase 2 |
↓Blood glucose level | — | — | — | — |
Wu et al., 2010 |
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Phase 2 |
— | — | ↓BMI | — | No changes in WHR |
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Gobert et al., 2010 |
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88 mg isoflavones (genistein, daidzein, and glycitein)/day |
No change in fasting and postprandial glucose or insulin levels | No change in indexes of insulin sensitivity and resistance | — | — | No change in HbA1c levels |
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Bertoglio et al., |
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↓Glucose level in blood | — | — | — | — |
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Bertoglio et al., |
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↓Glucose level in blood | — | — | — | — |
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Dove et al., 2011 [ |
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22 g lupin protein | ↓Postprandial glycaemia | — | — | — | — |
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Spadafranca et al., |
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Alpha-amylase inhibitor 6% * 100 mg |
↓Blood glucose |
↑Insulin level | — | ↓Food intake |
↓C-Peptide concentration in blood plasma |
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Choo et al., |
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Vitexin 1, 3, and 15 mg |
↓Postprandial glycaemia | — | — | — | — |
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Fu et al., 2012 [ |
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Genistein |
↓Hyperglycaemia |
↑Insulin levels in the blood |
No change | No change | — |
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Squadrito et al., |
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Genistein |
↓Glucose levels | ↓Insulin levels | No change | — |
↓Total cholesterol and triglyceride |
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Kim and Lim, 2013 [ |
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Genistein |
0.025 ↓FBG | No change | ↑Food intake | — | |
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Loi et al., |
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Alpha-amylase inhibitor/caffeoylquinic acid | ↓Blood glucose level | — | — | ↓Food intake | — |
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Park et al., 2013 [ |
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Daidzein 10 mg * kg body weight/day | ↓Postprandial glycaemia | — | — | — | — |
Yao and Ren, |
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Extruded adzuki bean extract |
↓Blood glucose level | — | — | — | — |
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Capraro et al., |
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↓Glucose level in blood | — | — | ↓Food intake | — |
Genistein and daidzein are two of the the best known flavonoids which have effects on secretory pancreas functions. Research confirms that these substances in physiologically achieved concentrations exert beneficial effects on the functions of pancreatic
Choi et al. tested the genistein and daidzein influence on glucose and insulin metabolism in nonfat mice, in which autoimmunological, insulin-dependent diabetes was developed [
Soya isoflavonoids also display the regulatory ability of triglyceride synthesis in the liver. According to the mentioned examination by Lu et al. carried out on nonobese, diabetic mice, soya isoflavonoids, genistein, and daidzein were applied at the ratio of 0.2 mg/kg lower glucose levels in blood thus decreasing triglyceride gradients in the liver. The research corroborated diminishing glucose-6-phosphatase activity and phosphoenolpyruvate carboxykinase (PEPCK) as well, together with a glucokinase activity increase, suggesting that genistein and daidzein block glucose production in the liver [
Cederroth et al. tested the effect of daidzein and genistein supplementation in healthy mice CD-1. As a result of a phytoestrogen rich diet (198 ppm daidzein and 286 ppm genistein) from the conception period up to adult age, AMP-activated protein kinase (AMPK) activation was observed in the liver and in white fatty tissue, as well as in muscles. This includes reduced lipid contents in adipocytes, increased phosphorylation of AMPK and acetyl-CoA carboxylase (ACC), increased expression of peroxisome proliferator-activated receptor gamma coactivator (PPAR-l
Kim and Lim studied diabetic mice which were divided into two groups according to fasting glucose levels (FBG): medium high FBG (DMMH; FBG 250–450 mg/dL) and high FBG (DMH; FBG 450–600 mg/dL). Mice were fed with different diets and further divided into the following groups (
Fu et al. tested 32 male C57BL/6 mice with obesity and diabetes generated by the high fat content of the diet and low dosage streptozotocin injections. The mice were divided into 4 groups (8 mice in each group) and fed a standard diet with 10% of calories from fat, a diet with a high fat content of 60% of calories from fat, and a diet containing 250 mg genistein/kg body weight. Consumption of genistein (250 mg/kg (−1)) resulted in improved hyperglycaemia, glucose tolerance, and insulin levels in the blood. This diet did not affect body weight gain, food intake, fat deposits, serum lipid profiles, or peripheral insulin sensitivity. Genistein caused an increase in the number of insulin-positive
Park et al. conducted research on male Slc: ICR mice in which diabetes was induced by injection of STZ, for the inhibitory effect of daidzein on alpha-amylase and alpha-glucosidase. Healthy mice and mice with STZ-induced diabetes were randomly divided into 3 groups of 7 mice. In the fasting state, the mice were orally administered soluble starch (2 g/kg) or daidzein, starch (10 mg/kg) or acarbose, and starch (10 mg/kg). The effect of daidzein in postprandial blood glucose levels was studied in normal and diabetic mice. Blood glucose levels in mice treated with daidzein were lower than in both the control mice and mice fed a diet supplemented with acarbose. When daidzein was added to healthy mice diet, the increase in postprandial blood glucose levels was significantly inhibited (
Clinical studies show conflicting results.
Genistein does not affect glucose transporter-2 expression or adenosine triphosphate (ATP) cellular production but increases pyruvate-stimulated insulin secretion in INS-1E cells, which indicates that insulin secretory function improvement through long-lasting exposure to genistein is not connected with alternative glucose uptake or glycolysis pathways. Increased insulin secretion due to genistein is connected with increased intracellular Ca2+ ion gradient and is protein kinase A dependent together with new proteins synthesis, and this effect is utterly blocked by N-[2-(p-bromocinnamylamino)ethyl]-5 or isoquinoline sulphonamide cycloheximide. These results prove that genistein may be a new bioactive compound displaying antidiabetic effects owing to pancreatic
In a randomized study of a 12-month, double-blind trial, a placebo controlled trial was attended by 120 women with metabolic syndrome, aged 49–67 years, and postmenopausal for at least 12 months. They received either genistein (
In a randomized, double-blind, placebo-controlled group, Gobert et al. studied the effects of soy protein and isoflavones and did not receive a positive result. Adults with type 2 diabetes (
When the authors considered the analysis of equol excretors as a variable in the statistical model the results were not changed and there was no significant interaction between equol production by individuals and diet treatment without the markers of glycemic control [
Proteins are one of the basic components of food but have different nutritional values because they contain very different amino acid compositions. The value is determined by the number of amino acids of proteins, their qualitative composition, bioavailability, and digestibility. Proteins ensure proper construction of tissue, regulate metabolic processes, and facilitate the absorption of minerals. Peptides derived from food proteins affect the circulatory system, nervous system, alimentary system, immune system, and functional properties. One of several activities is regulation of enzyme inhibitory peptides. At the cellular level proteins can act by inactivating ribosomes or inhibiting the active site cell, such as alpha-amylase inhibitors [
The monitoring of carbohydrate digestion as well as glucose absorption enables better control of postprandial glycaemia, especially after highly carbohydratic meals. Released glucose is absorbed by intestinal enterocytes through transmitters. Digestive enzyme inhibition or glucose transporters reduce glucose release and absorption in the small intestine and, as a consequence, suppress postprandial hyperglycaemia.
In the
In three experiments on healthy Wistar rats, Loi et al. studied the effect on hypoglycaemia and decreasing food intake of
White bean extract, apart from alpha-amylase inhibition, stimulates cholecystokinin (CCK) and disturbs the food uptake mechanism. A high ratio of phaseolamin application weakens rat growth speed [
Udani et al. tested the influence of water extract of a common white bean on weight loss and triglyceride level. The randomized examination was carried out using a double-blank test on a panel of 39 obese people (35 women and 4 men) who were given 1500 mg water extract of a common white bean with their meals, twice a day. The examination lasted 8 weeks. The results showed a higher weight loss and triglyceride level decrease in the group obtaining the extract. The differences were not statistically significant [
In a randomized, double-blind, placebo-controlled study examining 60 overweight (5–15 kg above) people, Celleno et al. showed that the use of Phase 2 results in a statistically significant decrease in body weight, fat mass, and WHR. Patients received either one 445 mg tablet of Phase 2 + 0.5 mg chromium picolinate or a placebo daily for 30 consecutive days prior to a meal rich in carbohydrates (2000–2200 calories). Body weight, BMI, fat mass, adipose tissue thickness, and waist,/hip/ thigh circumferences were reduced after 30 days [
Wu et al. in a randomized, double-blind, and placebo-controlled study examined 101 volunteers ( 50 placebo group and 51 study group) with a BMI between 25 and 40. The study group received two 1000 mg Phase 2 capsules or a reference substance in the form of two capsules containing microcrystalline cellulose of a volume and appearance of the capsules of Phase 2. Subjects treated with Phase 2 showed a statistically significantly greater decrease in both body weight 1.9 kg compared to 0.4 kg in the placebo group and waist circumference 1.9 cm compared to 0.4 cm. Accordingly, body weight and BMI dropped significantly too. There was no significant change in hip circumference. Among the biochemical parameters, only the creatinine value was higher and GPT lower in the group receiving Phase 2; however, the differences were not statistically significant [
In further studies, the authors obtained statistically significant results but the tested groups were not very large.
Udani and Singh research used a randomized, double-blank test method, which lasted 4 weeks and involved 25 healthy participants. Twice a day the tested subjects consumed 1000 mg fractionated white bean PVE or placebo between meals. All the tested participants were additionally subjected to a weight-loss plan which was based on a diet (some participants consumed high-carbohydratic meals) and exercises. In both groups, that obtaining the extract and that receiving the placebo, weight loss was observed. A division was made in respect to the amount of consumed carbohydrates. In the group placed in the highest tertile of carbohydrate uptake, the tested panel obtaining fractionated white bean PVE, there was a significantly bigger weight loss together with fatty mass decrease compared to the placebo group (
Udani et al. again tested Phase 2 impact on blood glucose levels in conducted open-label, crossover, 6-arm, randomized study of 13 people with a BMI of 18–25. This time the authors wanted to determine whether the addition of Phase 2 of high-GI foods (white bread) lowers GI. They carried out GI standardized tests by measuring blood glucose concentrations after consumption of white bread with butter, with and without the addition of Phase 2 in the form of capsules or powder. In both preparations, Phase 2 was administered at dosages up to 1500 mg, 2000 mg, and 3000 mg. Phase 2 powder was mixed with butter. The dosage of 2000 mg and 3000 mg Phase 2 capsules resulted in a slight reduction in GI. The dosage of 1500 mg and 2000 mg of Phase 2 powder caused a slight reduction in GI. A significant result was obtained with dosage of 3000 mg Phase 2 powder which is about 34.11% reduction in blood glucose levels after a meal (
Vinson et al. obtained similar results to Udani et al. when they conducted 2 studies, a crossover study and a placebo-controlled one. The first study involved 11 respondents (men and women, aged 21 to 57). Subjects were given 4 slices of white bread and 42 g margarine supplemented or not with 1500 mg of Phase 2. Phase 2 was added to the margarine. The meals were 610 calories and 60.5 g carbohydrates. Tests were made one week apart measuring glucose concentrations in blood plasma. In the study group average plasma glucose concentration versus the time curve was 66% lower compared to the control group (
Spadafranca et al., as with previous authors, studied the impact of PVE on the levels of glucose and insulin, C-peptide concentrations in blood plasma, and ghrelin after a meal and the impact on the control of appetite. A double-blind, randomized, crossover study included 12 healthy subjects (6 women, 6 men) aged 20–26 years, with normal weight (BMI: 19.7–23.5, fat: 31.5–11.5%). The subjects, in fasting state for at least 12 hours, received standardized meals consisting of a sandwich of white bread, ham, butter, and tomato +100 mg tablets of PVE (≥6% tested alpha-amylase inhibitor and phytohemagglutinin) or 100 mg placebo tablets. PVE or placebo tablets were consumed just before a meal. After a 7-day washout period the test was repeated. PVE supplementation reduced postprandial glucose, insulin, and C-peptide excursions and affected satiety sensations, inducing a lower desire to eat [
Alpha-glucosidase generated by the small intestine epithelium is one of the key enzymes responsible for carbohydrate digestion and triglyceride absorption. Its function is one of the modulating factors of postprandial hyperglycaemia. Intestinal alpha-glucosidase activity suppressors, just like alpha-amylase, may delay the digestion process and carbohydrate absorption and lower postprandial hyperglycaemia [
“Azuki” beans underwent thorough research into their biological activity. In Asia, especially in Japan, Korea, and China, this food is recommended as suitable for diabetic patients owing to its high alimentary fibre contents as well as protein [
Sreerama et al. in their research conducted on extracts of four-bean variations (mung, moth, red, and black “Azuki” variations) confirmed the biggest influence in terms of alpha-glucosidase blocking in the black “Azuki” bean variation. Mung beans showed the least activity [
In their research, Yao et al. for the first time ascribed compounds present in “Azuki” beans which are active and display alpha-glucosidase enzyme blocking activity. Using 70% of ethanol, the authors extracted four fractions out of “Azuki” beans. The ethyl acetate (EtOAc) soluble fraction manifested the biggest alpha-glucosidase blocking activity. Two major active components, vitexin and isovitexin, were isolated from “Azuki” beans. Fluorescent spectroscopy examination corroborated these flavonoid properties. The most beneficial effect is achieved at the temperature of 37°C, in laboratory conditions [
Earlier authors have studied the antidiabetic effects of mung bean sprout extract (MBS: DCI, vitexin and isovitexin: 24.16, 11.68, 5.40 mg/g) and mung bean seed coat extract (MBSC: DCI, vitexin and isovitexin: 0.0053, 15.22 and 11.42 mg/g) using mice with type 2 diabetes: 50 KK-Ay male mice and 10 healthy male mice C57BL/6. Diabetic mice were divided into five groups and fed different dosages MBS (1, 2, 3 g/kg), MBSC (3 g/kg), and without extracts. Group 6 included C57BL/6 mice. For all mice the following were measured: glucose blood, the plasma C-peptide, glucagon, total cholesterol, triglycerides, and blood urea nitrogen (BUN). Oral administration of MBS (3 and 2 g/kg) and MBSC (3 g/kg) showed lowered blood glucose levels compared with control KK-Ay mice. The supplementation of MBS (2 g/kg) and MBSC (3 g/kg) reversed the blood C-peptide and glucagon levels in type 2 diabetic animals as compared with untreated diabetic mice. In mice fed with MBSC and 3 and 2 g/kg MBS increases in triglycerides and total cholesterol level were eliminated. The plasma levels of BUN in MBS groups (2 g/kg) were lowered as compared with the KK-Ay mice control group. Mice which have taken MBS (2 g/kg) and MBSC (3 g/kg) had a significant increase in insulin immunoreactivity as compared with untreated diabetic mice [
Choo et al. obtained positive results in healthy and diabetic animals, and they also investigated the inhibitory effect of isovitexin and vitexin from
Authors used healthy mice and rats with STZ-induced diabetes divided into 8 groups of 6 animals. Six groups of mice were dosed by oral gavage at three different dosages (1 mg/kg, 3 mg/kg, and 15 mg/kg) of vitexin or isovitexin. A positive control group of mice were given acarbose (3 mg/kg). Six groups of rats were dosed by oral gavage with various dosages of vitexin (50, 100, and 200 mg/kg) or isovitexin (20, 50, and 100 mg/kg). Positive control rats received acarbose (5 mg/kg). After administration of treatments to mice and rats, they were treated with sucrose at 2.5 g/kg and 4 g/kg, respectively. Normoglycemic mice given 1 mg/kg vitexin showed a significant (
The extrusion is the next method to obtain extracts from “Azuki” beans. This method decreases the antioxidant activity in extruded “Azuki” beans by 41.86% and increases the antidiabetic activity in inhibited rat intestinal alpha-glucosidase in extruded “Azuki” beans by 307.60% compared to raw “Azuki” beans.
Yao and Ren studied the antidiabetic effects of extruded “Azuki” beans on 80 male rats fasting. In 40 rats, diabetes was induced using 45 mg/kg STZ. Healthy and diabetic rats were divided into 4 groups each: control group, positive control group (50 mg/kg acarbose), extract “Azuki” bean group (ABE, 200 mg/kg), and extract extruded “Azuki” bean group (EABE, 200 mg/kg). 30 minutes after administration of treatment the animals were orally administered fasted sucrose (2 g/kg). In the control group of healthy rats, blood glucose levels averaged 10.4 mmol/L 30 minutes after the administration of sucrose. In the group treated with EABE the glucose level after 30 min only averaged 8.79 mmol/L j in comparison with the control group. Blood glucose levels dropped by 15.6% in the treatment with EABE and by 22.6% in the treatment with acarbose. In the control group of diabetic rats blood glucose levels rose to an average of 31.2 mmol/L 30 minutes after sucrose administration. However, the measurement of blood glucose levels in the groups that received EABE and acarbose was difficult to do. Compared with the control group, the glucose level decreased by 28.4% in the case of administration of 300 mg/kg EABE and 23.0% when administered with 20 mg/kg acarbose [
For comparison, Maruyama et al. tested “Azuki” bean extract activity on a panel of 33 female students. The mean age of the 33 subjects was
Lupin plants, growing in popularity in Western Europe and Australia, are acknowledged alongside soya as one of the most valued vegetable protein sources. In
Capraro et al. studied controlled body weight gain and hypoglycemic properties proteins derived from Lupin plants including conglutin gamma. Authors observed by 3 weeks, two groups of rats (fed pasta with or without addition of pure protein from Lupinus). In the results a significant reduction in food intake and glycaemia was observed in animals fed pasta with supplemented lupin protein [
In another experiment, Bertoglio et al. investigated the characteristics of dried extract rich in conglutin gamma (conglutin gamma content was about 47% of the total proteins in the dry powder) in rats, and for the first time in humans. The animal study was conducted on 100 rats divided into 5 groups: placebo, positive control group (50 mg/kg metformin), and three groups with different dosages of conglutin gamma (10.5, 21.0, and 42.0 mg). 30 minutes before the glucose overloading experiment (2 g/kg) the treatment was administrated. At 0, 30, 60, and 90 min from glucose administration all rats received a dose of 50 mg/kg Na thiopental. Another part of the study concerned humans (a placebo-controlled study) and was performed on 15 healthy adult participants. By 7 weeks, participants were offered either one of three doses of powder from Lupin plant extract (750, 1500, and 3000 mg = 157.3, 315, and 630 mg conglutin gamma) or placebo 30 minutes before a meal consisting of 85 g of white rice (75 g carbohydrate). A study on rats showed a statistically significant correlation between the dosage of powder extract and blood glucose level. According to the dosage level of glucose, it was reduced by 14%, 42%, and 64%. The effect obtained after administration of the highest dosage was not different from the effect of the administration of 50 mg/kg metformin. The results of human studies confirmed the hypoglycemic properties of conglutin gamma. Compared to the control group, after three doses in 60 minutes lowered glucose levels averaged 81%. In 90 minutes, the 750 mg dosage caused an increase of the glucose level to 83% when compared to the placebo, but 1500 mg increased about 61% and the dosage of 3000 mg increased the glucose level about 71% compared to the placebo group. As a result of measurements of the areas under the curve glucose was significantly decreased by dosages of 1500 mg of 75% and 3000 mg of 79% compared to placebos. There were no significant differences in the level of serum insulin [
The interest in active components included in food is caused predominantly by the results of epidemiological examinations. In order to establish unambiguous evidence of the effectiveness of these compounds, including polyphenols, in their role as disease prophilaxy, it is indispensable to determine their bioavailability and next their biological activity. Bioavailability of assorted phenol compounds varies a lot, and those which are mostly consumed in a staple diet do not always manifest positive bioavailability profiles [
The majority of the research tasks dealing with the influence of phenol compounds coming from food products were conducted under
The main factors influencing polyphenol bioavailability are as follows: environmental factors (exposure to sun rays, maturity level), food product availability, cooking and heat treatment, homogenisation, lyophilisation, storage, and the presence of other compounds which suppress or enhance assimilation, compounds made with proteins or other polyphenols with similar absorption mechanisms, chemical structure, concentrations in food, the amounts consumed with food, enzyme activity, intestinal passage time, intestinal microflora composition, age, health condition, genetic factors, and physiological conditions [
Compounds found in leguminous plants, whose antidiabetic activity is supported by laboratory tests and on animal models (e.g. genistein, daidzein, alpha-amylase, and alpha-glucosidase inhibitors) display low bioavailability, genistein mainly due to its poor solubility in water. Alpha-amylase and alpha-glucosidase enzymes inhibitors lose their properties in heat treatment time [
Legumes should constitute a permanent dietary element in a balanced diet, especially with type 2 diabetic patients. Legumes are a source of wholesome protein, alimentary fiber, and bioactive substances displaying antioxidant activity together with anti-inflammatory and antineoplastic properties. The Leguminous plants should be employed in the promotion of a healthy lifestyle as a form of functional food. More studies are required to estimate the potential role of the leguminous plants in therapy including cancer, inflammation, and coronary diseases.
Adzuki bean extract/extruded adzuki bean extract
Acetyl-CoA carboxylase
a-Amylase inhibitor isoform 1
a-Amylase inhibitor isoform 2
a-Amylase inhibitor isoform like
AMP-activated protein kinase
Adenozynotrifosforan
Body mass index
Blood urea nitrogen
Concentrated Azuki
Cyclic adenosine monophosphate
Cholecystokinin
Diabetic mice control group
Diabetic mice height FBG/-control group
Diabetic mice medium hight FBG/-control group
Epigallocatechingallate
Ethylacetate
Fasting blood glucose
Glycemic index
Insulin-regulated glucose transporter
Glutamate pyruvate transaminase
Glucose-stimulated insulin secretion
Clone cells insulin secretion
Insulin receptor substrate 1
ATP-sensitive potassium
Mung bean sprouts extract/mung bean seed coat extract
Pathway mammalian target of rapamycin
Phosphoenolpyruvate carboxykinase
Peroxisome proliferator-activated receptor
Phytohaemagglutinin
Peroxisome proliferator-activated receptor alpha
Peroxisome proliferator-activated receptor gamma coactivator
Reactive oxygen species
Ribosomal protein S6 kinase beta-1
Hypoxia-regulated transcription factor
Diet containing soy protein/diet containing milk protein.
The authors declare that there is no conflict of interests.