tannins and Hyperglycemia

Diabetes mellitus is a group of metabolic disorders characterized by hyperglycaemia, and predicted by the World Health Organization as the expected 7th leading cause of death in 2030. Diabetes mellitus type 2 (DMT2) comprises the majority of diabetic individuals around the world (90%-95%). Pathophysiologically, this disorder results from a deregulation of glucose homeostasis, worsened by overweight and by a sedentary lifestyle, culminating in life-threatening cardiovascular events. The currently available anti-diabetic drugs are not devoid of undesirable side effects, sometimes responsible for poor therapeutic compliance. This represents a challenge for contemporary medicine, and stimulates research focused on the development of safer and more efficient anti-diabetic therapies. Amongst the most promising sources of new bioactive molecules, seaweeds represent valuable, but still underexploited, biofactories for drug discovery and product development. In this review, the role of phlorotannins, a class of polyphenols exclusively produced by brown seaweeds, in the management of DMT2 will be discussed, focusing on various pharmacologically relevant mechanisms and targets, including pancreatic, hepatic and intestinal enzymes, glucose transport and metabolism, glucose-induced toxicity and β-cell cytoprotection, and considering numerous in vitro and in vivo surveys.

Topics: alpha-Amylases; alpha-Glucosidases; Blood Glucose; Diabetes Mellitus, Type 2; Glycation End Products, Advanced; Humans; Hyperglycemia; Hypoglycemic Agents; Insulin-Secreting Cells; Phaeophyceae; Polyphenols; Seaweed; Tannins

It is well known that accumulation of advanced glycation ends products (AGEs) lead to various diseases such as diabetes and diabetic complications. In this study we showed that hydrolysable tannin from Sumac (Rhus typhina L.)-3,6-bis-O-di-O-galloyl-1,2,4-tri-O-galloyl-β-D-glucose (C

Topics: Antioxidants; Glucose; Glycation End Products, Advanced; Hyperglycemia; Rhus; Spectroscopy, Fourier Transform Infrared; Tannins

Topics: Adipose Tissue, White; Adiposity; Animals; Anti-Obesity Agents; Blood Glucose; Cholesterol; Diet, High-Fat; Dietary Sucrose; Disease Models, Animal; Dyslipidemias; Hyperglycemia; Hyperinsulinism; Hypoglycemic Agents; Hypolipidemic Agents; Insulin; Male; Mice, Inbred C57BL; Myrtaceae; Obesity; Phenols; Plant Extracts; Tannins; Time Factors; Weight Gain

We studied the influence of long-term treatment with sucrose and tannic acid in drinking water on the fatty acid profile and lipid peroxidation in rat testes. Male Wistar rats were supplemented with sucrose (30% w/v) or with sucrose and tannic acid (sucrose 30% w/v, tannic acid 0.1% w/v) in drinking water. The treatment with sucrose elevated blood glucose levels in the plasma (p < .05) and decreased the testis weight (p < .05) and testis index (p < .05) of the rats. Sucrose treatment increased monounsaturated fatty acids (MUFA) and C22:6n3, and decreased n6 fatty acids in testis tissue. Lipid peroxidation was significantly increased after sucrose administration in plasma (p < .05) and testis tissue (p < .01). The addition of tannic acid led to the decrease in lipid peroxidation in the plasma (p < .05) and testis (p < .05), a further increase in MUFA and decrease in n6 fatty acids. In conclusion, sucrose significantly altered the testis fatty acid profile with an increase in MUFA and C22:6n3, and a decrease in n6 fatty acids. Tannic acid attenuated oxidative stress and hyperglycaemia, but it did not improve pathological changes in the fatty acid composition of the testis.

Topics: Animals; Drinking Water; Fatty Acids; Fatty Acids, Unsaturated; Hyperglycemia; Hypoglycemic Agents; Lipid Peroxidation; Lipogenesis; Male; Oxidative Stress; Rats; Rats, Wistar; Sucrose; Sweetening Agents; Tannins; Testis

Topics: Acarbose; alpha-Amylases; alpha-Glucosidases; Animals; Blood Glucose; Flavonoids; Fruit; Glucose Tolerance Test; Hyperglycemia; Hypoglycemic Agents; Male; Mice; Phenols; Phoeniceae; Plant Extracts; Tannins

Corn silk (Zea mays L., Stigma maydis) is an important herb used traditionally in many parts of the world to treat array of diseases including diabetes mellitus. Inhibitors of α-amylase and α-glucosidase offer an effective strategy to modulate levels of post prandial hyperglycaemia via control of starch metabolism.. This study evaluated α-amylase and α-glucosidase inhibitory potentials of corn silk aqueous extract. Active principles and antioxidant attributes of the extract were also analysed.. The α-amylase inhibitory potential of the extract was investigated by reacting its different concentrations with α-amylase and starch solution, while α-glucosidase inhibition was determined by pre-incubating α-glucosidase with different concentrations of the extract followed by addition of p-nitrophenylglucopyranoside. The mode(s) of inhibition of the enzymes were determined using Lineweaver-Burke plot.. In vitro analysis of the extract showed that it exhibited potent and moderate inhibitory potential against α-amylase and α-glucosidase, respectively. The inhibition was concentration-dependent with respective half-maximal inhibitory concentration (IC50) values of 5.89 and 0.93mg/mL. Phytochemical analyses revealed the presence of alkaloids, flavonoids, phenols, saponins, tannins and phytosterols as probable inhibitory constituents. Furthermore, the extract remarkably scavenges reactive oxygen species like DPPH and nitric oxide radicals, elicited good reducing power and a significant metal chelating attributes.. Overall, the non-competitive and uncompetitive mechanism of action of corn silk extract is due to its inhibitory effects on α-amylase and α-glucosidase, respectively. Consequently, this will reduce the rate of starch hydrolysis, enhance palliated glucose levels, and thus, lending credence to hypoglycaemic candidature of corn silk.

Topics: Alkaloids; alpha-Amylases; alpha-Glucosidases; Antioxidants; Flavonoids; Glycoside Hydrolase Inhibitors; Hyperglycemia; Hypoglycemic Agents; Kinetics; Nitric Oxide; Phenols; Phytosterols; Plant Extracts; Poaceae; Reactive Oxygen Species; Saponins; Tannins; Zea mays

Medicinal plants have long been used against life-threatening diseases including diabetes, with more or less success. Some of these plants have been shown to possess antioxidant activities, which could help improving diabetes inconveniences. In that context, we investigated the effects of spirulina supplementation on alloxan-induced diabetic rats, hypothesizing that co-administration of spirulina with rat diet could ameliorate diabetes complications and provide as benefits as the common antidiabetic insulin. Following alloxan treatment, male Wistar rats were fed daily with 5% spirulina-enriched diet or treated with insulin (0.5 IU/rat) for 21 days. Both spirulina and insulin treatments of diabetic rats resulted in a significant reduction in fasting blood glucose and an increase of glycogen level. Spirulina supplementation also impeded loss of body weight and ameliorated hepatic toxicity indices, i.e. alkaline phosphatases and transaminases activities, bilirubin levels and lipid peroxidation. Besides, triglycerides, total cholesterol, and low-density lipoprotein cholesterol levels decreased in the serum. Moreover, diabetic rats fed with spirulina exhibited sig changes in antioxidant enzyme activities in the liver (ie, decrease in superoxide dismutase and increase in catalase and glutathione peroxidase activities). The beneficial effects of spirulina or insulin were confirmed by histological study of the liver of diabetic rats. Overall, this study indicates that treatment with spirulina decreased hyperglycemia and oxidative stress in diabetic rats, this amelioration being even more pronounced than that provided by insulin injection. Therefore, administration of this alga would be very helpful in the prevention of diabetic complications.

Topics: Alloxan; Animals; Anthocyanins; Blood Glucose; Catalase; Cholesterol; Diabetes Mellitus, Experimental; Diet; Flavonoids; Glycogen; Hyperglycemia; Hypoglycemic Agents; Insulin; Lipid Peroxidation; Liver; Male; Oxidative Stress; Rats; Rats, Wistar; Spirulina; Superoxide Dismutase; Tannins; Thiobarbituric Acid Reactive Substances; Triglycerides

In recent decades, there has been a drastic increase in the incidence and prevalence of diabetic mellitus. The aim of this study was to evaluate the in vitro inhibitory effect of Azadirachita indica leaf extract on the activity of alpha-amylase and alpha-glucosidase as a means of alleviating hyperglycemia and managing diabetes mellitus. Aqueous extract of Azadirachita indica exhibited most potent alpha-amylase inhibitory activity with IC50 value of 9.15 mg mL(-1) and acetone extract exhibited most potent alpha-glucosidase inhibitory activity with IC50 value of 5.00 mg mL(-1). Kinetic studies revealed both acetone and aqueous extract to exhibit mixed non-competitive inhibition for alpha-amylase and alpha-glucosidase. It can be concluded that the antidiabetic potential of Azadirachta indica may be due to its ability to inhibit both alpha-amylase and alpha-glucosidase. The presence of phytochemicals such as flavonoids, tannins and saponins in this plant may be responsible for its inhibitory activity on the two enzymes studied.

Topics: alpha-Amylases; alpha-Glucosidases; Azadirachta; Diabetes Mellitus; Enzyme Inhibitors; Flavonoids; Glycoside Hydrolase Inhibitors; Hyperglycemia; Hypoglycemic Agents; Kinetics; Plant Extracts; Plant Leaves; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Saponins; Tannins

The present work investigates protein tyrosine phosphatase 1B (PTP1B) and the α-glucosidase inhibitory activities of two edible brown algae, Ecklonia stolonifera and Eisenia bicyclis, as well as in their isolated phlorotannins. Since the individual extracts and fractions showed significant inhibitory activities, column chromatography was performed to isolate six phlorotannins, phloroglucinol (1), dioxinodehydroeckol (2), eckol (3), phlorofurofucoeckol-A (4), dieckol (5), and 7-phloroeckol (6). Phlorotannins 3-6 were potent and noncompetitive PTP1B inhibitors with IC(50) values ranging from 0.56 to 2.64 µM; 4-6 exhibited the most potent α-glucosidase inhibition with IC(50) values ranging from 1.37 to 6.13 µM. Interestingly, 4 and 6 were noncompetitive, while 5 exhibited competitive inhibition in an α-glucosidase assay. E. stolonifera and E. bicyclis as well as their isolated phlorotannins therefore possessed marked PTP1B and α-glucosidase inhibitory activities; this could lead to opportunities in the development of therapeutic agents to control the postprandial blood glucose level and thereby prevent diabetic complications.

Topics: alpha-Glucosidases; Benzofurans; Blood Glucose; Complex Mixtures; Diabetes Mellitus; Dioxins; Enzyme Inhibitors; Glycoside Hydrolase Inhibitors; Humans; Hyperglycemia; Hypoglycemic Agents; Kinetics; Magnetic Resonance Spectroscopy; Phaeophyceae; Phloroglucinol; Protein Tyrosine Phosphatase, Non-Receptor Type 1; Solutions; Spectrophotometry; Tannins; Yeasts