Anti-diabetic functional foods as sources of insulin secreting, insulin sensitizing and insulin mimetic agents

In Vitro Studies of Pumpkin (Cucurbita moschata var. Kashi Harit) Seed Protein Fraction(s) to Evaluate Anticancer and Antidiabetic Properties

Chronic diseases like cancer and diabetes are the major public health concerns of India and worldwide. Nowadays, plant-derived products are in great demand for the treatment of these diseases. Pumpkin seeds are traditionally implicated for their pharmacological properties, as exemplified by benign prostatic hyperplasia. Earlier, pumpkin seed proteins were extracted by the Osborne method, and their functional and nutritional qualities were evaluated. Here, the aim is to assess in vitro, the anticancer and antidiabetic properties of seed protein fractions. HepG2, MDA-MB-231, and MCF-7 cell lines were treated with water-soluble (WF) and alkali-soluble fractions (AF) to assess cytotoxicity, while pancreatic β-cells and insulin resistance (IR) - HepG2 cell lines were treated with WF to evaluate the antidiabetic potential. WF and AF showed cytotoxic effects towards HepG2 and MDA-MB-231 cell lines, suggesting apoptosis-mediated anticancerous activity. WF potentiates glucose-stimulated insulin secretion in pancreatic β-cells, in a dose-dependent manner. In IR-HepG2 cell line studies, control, metformin, and WF-treated groups showed uptake of glucose, when compared to the diabetic group, which is well-correlated with the upregulated expressions of GLUT2 and GLUT4 transporters in these groups. These results indicate that proteins from WF and AF may have anticancerous and antidiabetic properties and thus have the potential to utilize pumpkin proteins in the management of cancer and diabetes.

Functional foods of sub-Saharan Africa and their implications in the management of type 2 diabetes: A review

Throughout the world, the prevalence of metabolic diseases in general and type 2 diabetes (T2DM) in particular is constantly growing, and sub-Saharan Africa (SSA) is not spared. The use of functional foods is a more practical option among the different approaches used in the management of T2DM owing to the fact that they are relatively less costly, safer, and more accessible. In addition to their low glycemic index just like foods currently used to manage diabetes, functional foods contain bioactive compounds such as polyphenols, dietary fibers, saponins, and peptides. They are so named because they have additional health advantages beyond their basic nutritional worth. Bioactive compounds can be found in a variety of SSA plant-based foods, such as spices, fruits, vegetables, legumes, starchy foods, prepared foods, mixed foods, and prepared dishes. The goal of this review is to highlight some of the investigations into the effectiveness of local food and their antidiabetic mechanisms that have been studied in various SSA regions. Using the literature review as a basis, the authors state that SSA foods are rich in various bioactive compounds capable of regulating blood sugar through enhanced glucose tolerance, antioxidant effects, insulin sensitivity, and inhibition or activation of some key enzymes of the glucose metabolism that are linked to the prevention and management of T2DM. Many of the cited findings are preliminary, obtained from cell and preclinical studies, and therefore other studies need to be done to demonstrate the full potential of these foods to serve as bases for dietary guidelines.

Prospective Nutraceutical Effects of Cinnamon Derivatives Against Insulin Resistance in Type II Diabetes Mellitus-Evidence From the Literature

Apart from advances in pharmaceutical antidiabetic agents, efforts are being made toward hypoglycemic agents derived from natural sources. Cinnamon has been reported to have significant benefits for human health, particularly as an anti-inflammatory, antidiabetic, and anti-hypertriglyceridemic agent. The phytochemicals in cinnamon can be extracted from different parts of plant by distillation and solvent extraction. These chemicals help in decreasing insulin resistance and can act against hyperglycemia and dyslipidemia, inflammation and oxidative stress, obesity, overweight, and abnormal glycation of proteins. Cinnamon has shown to improve all of these conditions in in vitro, animal, and/or human studies. However, the mechanism of action of active ingredients found in cinnamon remains unclear. The current review presents the outstanding ability of cinnamon derivatives to control diabetes by various pathways modulating insulin release and insulin receptor signaling. It was also found that the type and dosage of cinnamon as well as subject characteristics including drug interactions are likely to affect the response to cinnamon. Future research directions based on this review include the synergistic usage of various cinnamon derivatives in managing and/or preventing diabetes and possible other relevant chronic diseases.

Chemical Characterization, α-Glucosidase, α-Amylase and Lipase Inhibitory Properties of the Australian Honey Bee Propolis

The use of functional foods and nutraceuticals as a complementary therapy for the prevention and management of type 2 diabetes and obesity has steadily increased over the past few decades. With the aim of exploring the therapeutic potentials of Australian propolis, this study reports the chemical and biological investigation of a propolis sample collected in the Queensland state of Australia which exhibited a potent activity in an in vitro α-glucosidase inhibitory screening. The chemical investigation of the propolis resulted in the identification of six known prenylated flavonoids including propolins C, D, F, G, H, and solophenol D. These compounds potently inhibited the α-glucosidase and two other enzymes associated with diabetes and obesity, α-amylase, and lipase on in vitro and in silico assays. These findings suggest that this propolis is a potential source for the development of a functional food to prevent type 2 diabetes and obesity. The chemical analysis revealed that this propolis possessed a chemical fingerprint relatively similar to the Pacific propolis found in Okinawa (South of Japan), Taiwan, and the Solomon Islands. This is the first time the Pacific propolis has been identified in Australia.

Clinical efficacy of capsules containing standardized extract of Bauhinia forficata Link (pata-de-vaca) as adjuvant treatment in type 2 diabetes patients: A randomized, double blind clinical trial

ETHNOPHARMACOLOGICAL RELEVANCE

Bauhinia forficata Link, is a Brazilian native plant and popularly known as pata-de-vaca ("paw-of-cow"). The tea prepared with their leaves has been extensively used in the Brazilian traditional practices for the diabetes treatment. The aim of the present study was to investigate the effect of capsules containing granules of a standardized extract of B. forficata leaves as adjuvant treatment on the glycemic control of patients with type-2 diabetes melitus.

MATERIALS AND METHODS

A double-blind, randomized clinical trial using capsules containing granules prepared by wet granulation of a standardized extract from B. forficata leaves as adjuvant treatment, was conducted. 92 patients aged 18-75 years from an outpatient clinic with type-2 diabetes were randomly assigned by a simple randomization scheme, in a 1:1 ratio to receive capsules of B. forficata or placebo for four months. The capsules used contain 300 mg of standardized extract from B. forficata leaves, yielding 2% of total flavonoid content per capsule. Primary outcome was glycated hemoglobin levels and fasting plasma glucose at 4 months. Possible harms were also determined.

RESULTS

The findings showed that at 4 months, the mean fasting plasma glucose levels and glycated hemoglobin were both significantly lower in the B. forficata group than in the placebo group.

CONCLUSION

The present study suggests that the adjunctive use of capsules containing standardized extract of B. forficata can add to regular oral anti-diabetics in the metabolic and inflammatory control of type-2 diabetes patients.

Antidiabetic Phytochemicals From Medicinal Plants: Prospective Candidates for New Drug Discovery and Development

Diabetes, a chronic physiological dysfunction affecting people of different age groups and severely impairs the harmony of peoples' normal life worldwide. Despite the availability of insulin preparations and several synthetic oral antidiabetic drugs, there is a crucial need for the discovery and development of novel antidiabetic drugs because of the development of resistance and side effects of those drugs in long-term use. On the contrary, plants or herbal sources are getting popular day by day to the scientists, researchers, and pharmaceutical companies all over the world to search for potential bioactive compound(s) for the discovery and development of targeted novel antidiabetic drugs that may control diabetes with the least unwanted effects of conventional antidiabetic drugs. In this review, we have presented the prospective candidates comprised of either isolated phytochemical(s) and/or extract(s) containing bioactive phytoconstituents which have been reported in several in vitro, in vivo, and clinical studies possessing noteworthy antidiabetic potential. The mode of actions, attributed to antidiabetic activities of the reported phytochemicals and/or plant extracts have also been described to focus on the prospective phytochemicals and phytosources for further studies in the discovery and development of novel antidiabetic therapeutics.

Cabbage (Brassica oleracea var. capitata): A food with functional properties aimed to type 2 diabetes prevention and management

Type 2 diabetes mellitus (T2DM) is increasing the prevalence worldwide at an alarming rate, becoming a serious public health problem that mainly affects developing countries. Functional food research is currently of great interest because it contributes to developing nutritional therapy strategies for T2DM prevention and treatment. Bioactive compounds identified in some plant foods contribute to human health by mechanisms of action that exert biological effects on metabolic pathways involved in the development of T2DM. Hence, vegetables with high bioactive compounds content may be a source of functional value for the control of T2DM. Cabbages varieties (Brassica oleracea var. capitata) such as green (GCB), white (WCB), and red (RCB) are foods consumed (raw or cooked) and cultivated in different regions of the world. Scientific evidence shows that cabbage has multi-target effects on glucose homeostatic regulation due to its high content of bioactive compounds. It has also been shown to decrease damage to organs affected by T2DM complications, such as the liver and kidney. Additionally, it could contribute as a preventive by attenuating problems underlying the development of T2DM as oxidative stress and obesity. This review highlights the functional properties of cabbage varieties involved in glucose regulation and the main mechanisms of the action exerted by their bioactive compounds. In conclusion, cabbage is a valuable food that can be employed as part of nutritional therapy or functional ingredient aimed at the prevention and treatment of T2DM.

Kudzu Resistant Starch: An Effective Regulator of Type 2 Diabetes Mellitus

Kudzu is a traditional medicinal dietary supplement, and recent research has shown its significant benefits in the prevention/treatment of type 2 diabetes mellitus (T2DM). Starch is one of the main substances in Kudzu that contribute decisively to the treatment of T2DM. However, the underlying mechanism of the hypoglycemic activity is not clear. In this study, the effect of Kudzu resistant starch supplementation on the insulin resistance, gut physical barrier, and gut microbiota was investigated in T2DM mice. The result showed that Kudzu resistant starch could significantly decrease the value of fasting blood glucose and the levels of total cholesterol, total triglyceride, and high-density lipoprotein, as well as low-density lipoprotein, in the blood of T2DM mice. The insulin signaling sensitivity in liver tissue was analyzed; the result indicated that intake of different doses of Kudzu resistant starch can help restore the expression of IRS-1, p-PI3K, p-Akt, and Glut4 and thus enhance the efficiency of insulin synthesis. Furthermore, the intestinal microorganism changes before and after ingestion of Kudzu resistant starch were also analyzed; the result revealed that supplementation of KRS helps to alleviate and improve the dysbiosis of the gut microbiota caused by T2DM. These results validated that Kudzu resistant starch could improve the glucose sensitivity of T2DM mice by modulating IRS-1/PI3K/AKT/Glut4 signaling transduction. Kudzu resistant starch can be used as a promising prebiotic, and it also has beneficial effects on the gut microbiota structure of T2DM mice.

Antihyperglycemic and hypoglycemic activity of Mayan plant foods in rodent models

BACKGROUND

Postprandial hyperglycemia and decreased insulin secretion are relevant to risk factors in the development of type 2 diabetes and its complications. Plant foods with antidiabetic properties could be an affordable alternative in the prevention and treatment of this disease. In the present study, the antihyperglycemic and hypoglycemic activity of Bixa orellana, Psidium guajava L., Cucurbita moschata, Raphanus sativus L. and Brassica oleracea var. capitata - Mayan plant foods - were evaluated at doses of 5 and 10 mg kg^-1 . Antihyperglycemic activity was measured in healthy Wistar rats and those with obesity induced by high-sucrose diet (group HSD) (20%). The hypoglycemic activity was measure in healthy CD1 mice.

RESULTS

Fasting glucose, Lee index and the body weight of HSD rats increased significantly (P ≤ 0.05) after 12 weeks of induction compared to healthy rats. In healthy rats, P. guajava and Bixa orellana (10 mg kg^-1 ) demonstrated higher and statistically different (P ≤ 0.05) antihyperglycemic activity compared to control acarbose (0.5 mg kg^-1 ). In the HSD rat group, all Mayan plant foods (10 mg kg^-1 ) demonstrated antihyperglycemic activity statistically equal (P ≤ 0.05) to control acarbose. However, Brassica oleracea and R. sativus registered the highest antihyperglycemic activity. Bixa orellana and P. guajava (5 mg kg^-1 ) showed similar hypoglycemic activity (P ≤ 0.05) to glibenclamide (0.5 mg kg^-1 ) but was not significant (P ≤ 0.05) compared to insulin (5 UI kg^-1 ).

CONCLUSION

The present study provides valuable evidence on the possible health benefits of Mayan plant foods. These foods could contribute to the development of therapeutic diet strategies for the prevention and treatment of diabetes. © 2021 Society of Chemical Industry.

Ameliorative effect of white tea from 50-year-old tree of Camellia sinensis L. (Theaceae) on kidney damage in diabetic mice via SIRT1/AMPK pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetic kidney damage (DKD) is one of the most common complications of diabetes, which is known as a chronic inflammatory kidney disease caused by persistent hyperglycemia. White tea was originally used as a folk medicine to treat measles in ancient China. What arouses our interest is that there is a traditional method to treat diabetes with white tea taken from over 30-year-old tree of Camellia sinensis L. However, there are few reports on the renal protection of white tea.

AIM OF THE STUDY

This present study was designed to study the potential protective effects of white tea (WT) and old tree white tea (OTWT) on high-fat-diet (HFD) combined with streptozotocin (STZ)-induced type 2 diabetic mice to explore the possible mechanism of WT/OTWT against DKD.

MATERIALS AND METHODS

C57BL/6 mice were randomly divided into four groups: NC, T2D, WT (400 mg/kg·b.w, p.o.), OTWT (400 mg/kg·b.w, p.o.). Diabetes was established in all groups except NC group, by six weeks of HFD feeding combined with STZ (50 mg/kg, i.p.) for 3 times, treatments were administered for six weeks and then all the animals were decapitated; kidney tissues and blood samples were collected for the further analysis, including: levels of insulin, lipid metabolism (TG, TC, HDL, LDL, FFA), antioxidative enzymes (catalase (CAT), super oxide dismutase (SOD), glutathione peroxidase (GPx)), blood urea nitrogen (BUN) and creatine, inflammatory cytokines (TNF-α, IL-1β, COX-2, iNOS, MCP-1), advanced glycation end products (AGE), receptor of AGE (RAGE), Nrf2, AMPK, SIRT1, and PGC-1α. H&E, PAS and Masson staining were performed to examine the histopathological alterations of the kidneys.

RESULTS

Our data showed that WT and OTWT reversed the abnormal serum lipids (TG, TC, HDL, LDL, FFA) in T2D mice, upregulated antioxidative enzymes levels (CAT, SOD, GPx) and inhibit the excessive production of proinflammatory mediators (including MCP-1, TNF-α, IL1β, COX-2 and iNOS) by varying degrees, and OTWT was more effective. In histopathology, OTWT could significantly alleviate the accumulation of renal AGE in T2D mice, thereby improving the structural changes of the kidneys, such as glomerular hypertrophy, glomerular basement membrane thickening and kidney FIbrosis.

CONCLUSIONS

Both WT and OTWT could alleviate the diabetic changes in T2D mice via hypoglycemic, hypolipidemic, anti-oxidative and anti-inflammatory effects, while OTWT was more evident. OTWT could prominently alleviate the accumulation of AGE in the kidneys of T2D mice, thereby ameliorating the renal oxidative stress and inflammatory damage, which was associated with the activation of SIRT1/AMPK pathway.

Phenolic compounds and antioxidant properties of wheat fermented with Agaricus brasiliensis and Agaricus bisporus

Solid-state fermentation with Agaricus brasiliensis and Agaricus bisporus on whole grain wheat was carried out. Phenolic compounds and antioxidant properties of fermented wheat were determined. The results showed that the maximum values of polyphenols contents in wheat fermented with A. brasiliensis and A. bisporus reached, respectively (3.16 ± 0.21) and (3.93 ± 0.23) mg GAE/g, which were 2.90 and 3.61 times of unfermented control. By employing ultra performance liquid chromatography coupled to mass spectrometry (UPLC-MS), 18 kinds of phenolic compounds were identified from fermented wheat. Compared with control, only 4-hydroxy-benzaldehyde was the same compound. It indicated that fermentation with the two fungi changed polyphenols contents and phenolic compounds composition in wheat to a great extent. Among these phenolic compounds, except for 4-hydroxy-benzaldehyde, 4-hydroxy-benzoic acid and β-N-(γ-glutamyl)-4-formylphenylhydrazine, other 15 kinds of phenolic compounds were first identified from mushroom samples (including fruit bodies, mycelia and fermentation products). DPPH radical scavenging capacity, reducing power, ferrous ion chelating ability and inhibition of lipid peroxidation of fermented wheat were significantly stronger than control (P < 0.05).

Effects of different levels of dietary black cumin (Nigella sativa L.) and fenugreek (Trigonella foenum-graecum L.) and their combination on productive traits, selected blood constituents, microbiota and immunity of broilers

The effects of inclusion of powdered seeds of black cumin (B) (Nigella sativa L.) and fenugreek (F) (Trigonella foenum-graecum L.) on productive traits, selected blood constituents, microbiota and immunity of broilers were studied. A total of 648 day-old chicks were randomly assigned to nine treatments, with four pen replicates, each with 18 birds, including three levels of B seed powder (BSP; 0, 5 or 10 g/kg) and three levels of F seed powder (FSP; 0, 5 or 10 g/kg) in a 3 × 3 factorial arrangement. Neither powder affected feed intake. The FSP increased (p = 0.048) feed conversion ratio (FCR), but decreased daily BW gain (p = 0.02) between days 0 and 21, while BSP increased daily gain between days 22 and 42 and overall (both p = 0.005). Abdominal fat was decreased (p = 0.003) by BSP. Blood constituents were unaffected by either powder, but ileal Escherichia coli were decreased (p = 0.039) at day 42. The BSP increased a range of immunological titers, where BSP affected positively the measured variables. The interactions between BSP and FSP, specifically on broiler carcass cuts, suggested that where BSP is included at 10 g/kg, the inclusion of FSP at the same level may provide no additional benefit. Thus, while either powder could be included separately, the co-inclusion of both at 10 g/kg is not recommended.

Hypoglycemic effect and bioactive compounds associated with the ripening stages of the Cucurbita ficifolia Bouché fruit

BACKGROUND

The fruit of Cucurbita ficifolia Bouché is known in Mexico as 'chilacayote'. The scientific interest that C. ficifolia Bouché has acquired is due to its important hypoglycemic effect. The present research aimed (i) to discover whether this hypoglycemic property is present at different stages of development of this fruit, and (ii) to characterize some bioactive compounds with antioxidant or anti-inflammatory properties. Ethylene production, respiration rate, and maturity indices were determined during fruit development. The chemical characterization of the aqueous extracts of each stage of maturity studied was determined and their hypoglycemic effects were bioassayed using groups of normal mice with diabetes induced by streptozotocin at a dose of 500 mg^-1 kg^-1 body weight.

RESULTS

Respiration rate and ethylene production showed a typical pattern for non-climacteric fruit and the quality parameters did not show significant changes. Phenolic compounds such as gallic acid and chlorogenic acid were found to have the highest concentration at 15 days of development. Extracts at 15 days showed a hypoglycemic effect that was 11% greater than that of glibenclamide in diabetized mice.

CONCLUSION

All stages of development of C. ficifolia fruit had a hypoglycemic effect; however, the aqueous extract from the fruit at 15 days of development showed a better effect than glibenclamide. This finding highlights the potential of this maturity stage, and shows that it is appropriate for inclusion in treatments of type 2 diabetes mellitus. The results also indicate that phenolic compounds are mainly responsible for this effect and not d-chiro-inositol as previously thought. © 2020 Society of Chemical Industry.

Structural characterization of a homopolysaccharide with hypoglycemic activity from the roots of Pueraria lobata

A water-soluble neutral homopolysaccharide (PLP-1) was obtained from the roots of Pueraria lobata by DEAE cellulose and Sephadex G-200 gel chromatography purification. The average molecular weight of PLP-1 was 16.2 kDa. Monosaccharide composition analysis showed that PLP-1 was composed of glucose as a glucan. The structure of PLP-1 was characterized on the basis of extensive physical and chemical analysis, which indicated that the backbone of PLP-1 was mainly composed of →3)-α-d-Glcp(1→ and →4)-β-d-Glcp(1→ with a molar ratio of 7.0 : 1.0. Moreover, the hypoglycemic activity of PLP-1 was investigated by palmitic acid and high glucose induced insulin resistant HepG2 cells. The results elucidated that PLP-1 could decrease the glucose concentration by up-regulating the expression of PI3K and AKT, and down-regulating the expression of FoxO1, PCK2, and G6Pase in insulin resistant cells. Therefore, PLP-1 could serve as a dietary supplement to ameliorate insulin resistance for diabetic patients.

Physicochemical properties of polysaccharide fractions from Sargassum fusiforme and their hypoglycemic and hypolipidemic activities in type 2 diabetic rats

Two polysaccharide fractions (SFPs, designated as respectively SFP-1 and SFP-2) were acquired from Sargassum fusiforme by ultrasound-assisted enzymatic extraction, and their physicochemical properties and hypoglycemic and hypolipidemic effects were investigated. Structural analysis indicated that SFPs were obvious different in the zeta potential, molecular weight distribution, characteristic organic group, microstructure and the contents of total sugar, uronic acid, sulfate and moisture. SFPs consisted of fucose, mannose, rhamnose, glucose, galactose and glucuronic acid with different molar ratios. Congo red test explained that SFPs had no triple-helix structure. SFP-1 exhibited lower viscosity due to its lower molecular weight. Regarding to hypoglycemic and hypolipidemic effects, oral administration of SFPs prominently restrained loss of body weight and increase of water intake, and also significantly controlled the increase of levels of fasting blood glucose, triglyceride (TG), total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), uric acid (UA), urea nitrogen (BUN), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) of diabetic rats, and SFP-2 showed better effects in controlling fasting blood glucose, ALT, UA and BUN levels. Intervention of SFP-2 reduced the levels of insulin, FFA and TBA of diabetic rats. Histomorphological observation further demonstrated that SFPs could attenuate liver and kidney damage caused by hyperglycemia and hyperlipidemia. Data indicated that SFPs, especially SFP-2, significantly improved hyperglycemia, hyperlipidemia and liver and kidney function of diabetic rats.

Insulin signaling pathway and related molecules: Role in neurodegeneration and Alzheimer's disease

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases. Its major pathological hallmarks, neurofibrillary tangles (NFT), and amyloid-β plaques can result from dysfunctional insulin signaling. Insulin is an important growth factor that regulates cell growth, energy utilization, mitochondrial function, autophagy, oxidative stress, synaptic plasticity, and cognitive function. Insulin and its downstream signaling molecules are located majorly in the regions of cortex and hippocampus. The major molecules involved in impaired insulin signaling include IRS, PI3K, Akt, and GSK-3β. Activation or inactivation of these major molecules through increased or decreased phosphorylation plays a role in insulin signaling abnormalities or insulin resistance. Insulin resistance, therefore, is considered as a major culprit in generating the hallmarks of AD arising from neuroinflammation and oxidative stress, etc. Moreover, caspases, Nrf2, and NF-κB influence this pathway in an indirect way. Various studies also suggest a strong link between Diabetes Mellitus and AD due to the impairment of insulin signaling pathway. Moreover, studies also depict a strong correlation of other neurodegenerative diseases such as Parkinson's disease and Huntington's disease with insulin resistance. Hence this review will provide an insight into the role of insulin signaling pathway and related molecules as therapeutic targets in AD and other neurodegenerative diseases.

Jiaogulan tea (Gpostemma pentaphyllum) potentiates the antidiabetic effect of white tea via the AMPK and PI3K pathways in C57BL/6 mice

The use of plant-based beverages to interfere with the onset of diabetes may be a promising approach towards type 2 diabetes mellitus (T2DM).

Cinnamon Shows Antidiabetic Properties that Are Species-Specific: Effects on Enzyme Activity Inhibition and Starch Digestion

Despite considerable research the evidence around the antidiabetic properties of cinnamon remains equivocal, and this may be due to varietal differences which is an aspect that is understudied. This study systematically compared the anti-hyperglycaemic properties of the four major commercial cinnamon types used around the world (Chinese; Cinnamomum cassia [CC], Indonesian; C. burmanii [IC], Vietnamese; C. loureirii [VC], and Ceylon; C. zeylanicum [SC]). LC-MS analysis showed distinct diffrences in the phytochemical profiles of cinnamon with SC showing the lowest coumarin concentration. CC and IC had the highest polyphenol levels and antioxidant potential, and all four types differed significantly in their content (P < 0.001). All cinnamon types showed potent species-specific effects on starch digestion enzyme activity inhibition (P < 0.001), CC was most effective against α-amylase and all four strongly inhibited α-glucosidase compared to acarbose. Cinnamon significantly reduced starch breakdown during oral (P = 0.006) and gastric (P = 0.029) phases of gastro-intestinal digestion with IC and SC showing consistent effects. No effects of cinnamon were seen in the intestinal phase. IC, VC and SC showed the greatest potential to inhibit formation of advanced glycation endproducts (AGEs) during digestion. In conclusion, cinnamon demonstrates anti-hyperglycaemic properties, however effects are species-specific with best overall properties seen for Ceylon cinnamon.

Effect of Ishophloroglucin A, A Component of Ishige okamurae, on Glucose Homeostasis in the Pancreas and Muscle of High Fat Diet-Fed Mice

Ishophloroglucin A (IPA), a component of Ishige okamurae (IO), was previously evaluated to standardize the antidiabetic potency of IO. However, the potential of IPA as a functional food for diabetes prevention has not yet been evaluated. Here, we investigated if 1.35 mg/kg IPA, which is the equivalent content of IPA in 75 mg/kg IO, improved glucose homeostasis in high-fat diet (HFD)-induced diabetes after 12 weeks of treatment. IPA significantly ameliorated glucose intolerance, reducing fasting glucose levels as well as 2 h glucose levels in HFD mice. In addition, IPA exerted a protective effect on the pancreatic function in HFD mice via pancreatic β-cells and C-peptide. The level of glucose transporter 4 (GLUT4) in the muscles of HFD mice was stimulated by IPA intake. Our results suggested that IPA, which is a component of IO, can improve glucose homeostasis via GLUT4 in the muscles of HFD mice. IO may be used as a functional food for the prevention of diabetes.

Capsaicin Analogues Derived from n-3 Polyunsaturated Fatty Acids (PUFAs) Reduce Inflammatory Activity of Macrophages and Stimulate Insulin Secretion by β-Cells In Vitro

In this study, two capsaicin analogues, N-eicosapentaenoyl vanillylamine (EPVA) and N-docosahexaenoyl vanillylamine (DHVA), were enzymatically synthesized from their corresponding n-3 long chain polyunsaturated fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), both dietary relevant components. The compounds significantly reduced the production of some lipopolysaccharide (LPS)-induced inflammatory mediators, including nitric oxide (NO), macrophage-inflammatory protein-3α (CCL20) and monocyte chemoattractant protein-1 (MCP-1 or CCL2), by RAW264.7 macrophages. Next to this, only EPVA increased insulin secretion by pancreatic INS-1 832/13 β-cells, while raising intracellular Ca2+ and ATP concentrations. This suggests that the stimulation of insulin release occurs through an increase in the intracellular ATP/ADP ratio in the first phase, while is calcium-mediated in the second phase. Although it is not yet known whether EPVA is endogenously produced, its potential therapeutic value for diabetes treatment merits further investigation.

Spice-Derived Bioactive Ingredients: Potential Agents or Food Adjuvant in the Management of Diabetes Mellitus

Spices possess tremendous therapeutic potential including hypoglycemic action, attributed to their bioactive ingredients. However, there is no study that critically reviewed the hypoglycemic potency, safety and the bioavailability of the spice-derived bioactive ingredients (SDBI). Therefore, the aim of the study was to comprehensively review all published studies regarding the hypoglycemic action of SDBI with the purpose to assess whether the ingredients are potential hypoglycemic agents or adjuvant. Factors considered were concentration/dosages used, the extent of blood glucose reduction, the IC50 values, and the safety concern of the SDBI. From the results, cinnamaldehyde, curcumin, diosgenin, thymoquinone (TQ), and trigonelline were showed the most promising effects and hold future potential as hypoglycemic agents. Conclusively, future studies should focus on improving the tissue and cellular bioavailability of the promising SDBI to achieve greater potency. Additionally, clinical trials and toxicity studies are with these SDBI are warranted.

Protective effect of rosmarinic acid and carnosic acid against streptozotocin-induced oxidation, glycation, inflammation and microbiota imbalance in diabetic rats

This study evaluated the protective effects of two rosemary components, rosmarinic acid (RA) and carnosic acid (CA), against hypoglycemia, hyperlipidemia, oxidative stress and an imbalanced gut microbiota architecture in diabetic rats. Treatment with RA and CA (30 mg kg-1) decreased the levels of fasting plasma glucose (23.7%, 15.6%), total cholesterol (30.4%, 14.1%) and triglyceride (65.7%, 47.8%) at 15 weeks. RA and CA also exhibited an anti-oxidative and anti-glycative effect by lowering the formation of malondialdehyde and advanced glycation end products. In addition, they showed protective effects against tissue damage and inflammation in the abdominal aorta, based on microscopic observations and the analysis of protein expression. Finally, the prebiotic effects of RA and CA on gut microbiota were demonstrated by increasing the population of diabetes-resistant bacteria and decreasing the amounts of diabetes-sensitive bacteria. Overall, RA showed a stronger protective effect than CA in mitigating diabetic symptoms in rats.

Phenolic compounds and biological effects of edible Rumex scutatus and Pseudosempervivum sempervivum: potential sources of natural agents with health benefits

The present study outlines a chemical characterization and further effects beneficial to health of edible Rumex scutatus and Pseudosempervivum sempervivum, in addition to presenting the antioxidant, enzyme inhibitory effects and antimicrobial properties of different extracts. The phenolic compounds composition of the extracts was assessed by RP-HPLC-DAD, outlining benzoic acid and rutin as major constituents in P. sempervivum and rutin and hesperidin in R. scutatus. Moreover, further biological effects were tested on key enzymes involved in diabetes mellitus, Alzheimer's disease and skin melanogenesis revealing an important tyrosinase inhibitory effect of Pseudosempervivum water extract. Moreover, both species possessed antimicrobial properties towards bacteria and fungi relevant to public health. Accordingly, we find that R. scutatus and P. sempervivum can be considered as novel functional foods because they are rich sources of biologically active compounds that provide health benefits.

Phenolic Acid Content and Antioxidant Properties of Extruded Corn Snacks Enriched with Kale

Prohealth food contains specific components which have positive influence on the health and well-being of the consumer. An important position among bioactive compounds occurs for polyphenols. Many results have indicated that an increased intake of phenolic compounds may reduce the risk of cardiovascular diseases and type 2 diabetes. The objective of the study was production of extruded corn snacks with addition (0, 2, 4, 6, and 8%) of kale (Brassica oleracea L. var. sabellica)-a polyphenol-rich plant. Afterwards, high-performance liquid chromatography-mass spectrometry (LC-ESI-MS/MS) and antioxidant activity analyses of snack extracts were performed. In the corn snacks enriched with kale, fifteen phenolic acids were indicated. These were protocatechuic, 4-OH-benzoic, vanillic, trans-caffeic, cis-caffeic, trans-p-coumaric, cis-p-coumaric, trans-ferulic, cis-ferulic, salicylic, gentisic, syringic, 3-OH-cinnamic, trans-sinapic, and cis-sinapic acids. Both the qualitative and quantitative content of polyphenols increased with the addition of B. oleracea. Data from spectrophotometric analyses of the samples showed high DPPH radical scavenging potential of snacks enriched with 4, 6, and 8% of kale. Snacks enriched with kale contain high level of phenolic acids and, therefore, have great potential to make a valuable source of natural antioxidants. High-temperature short-time extrusion-cooking process had no negative impact on polyphenol's activity.

Cellular apoptosis and cardiac dysfunction in STZ-induced diabetic rats attenuated by anthocyanins via activation of IGFI-R/PI3K/Akt survival signaling

Anthocyanins are known cyto-protective agents against various stress conditions. In this study cardio-protective effect of anthocyanins from black rice against diabetic mellitus (DM) was evaluated using a streptozotocin (STZ)-induced DM rat model. Five-week-old male Wistar rats were administered with STZ (55 mg kg^-1 , IP) to induce DM; rats in the treatment group received 250 mg oral anthocyanin/kg/day during the 4-week treatment period. DM and the control rats received normal saline through oral gavage. The results reveal that STZ-induced DM elevates myocardial apoptosis and associated proapoptotic proteins but down-regulates the proteins of IGF1R mediated survival signaling mechanism. Furthermore, the functional parameters such as the ejection-fraction and fraction-shortening in the DM rat hearts declined considerably. However, the rats treated with anthocyanins significantly reduced apoptosis and the associated proapoptotic proteins and further increased the survival signals to restore the cardiac functions in DM rats. Anthocyanin supplementation enhances cardiomyocyte survival and restores cardiac function.

The novel contributors of anti-diabetic potential in mulberry polyphenols revealed by UHPLC-HR-ESI-TOF-MS/MS

To explore the comprehensive phenolic profile of mulberry (Morus alba L.) fruit and reveal the novel anti-diabetic constituents, mulberry polyphenols (MP) were fractionated through gradient ethanol elution and subjected to composition and bioactivity analysis. Forty-seven phenolic compounds were identified and quantified through UHPLC-HR-ESI-TOF-MS/MS, including twenty-one newly identified compounds such as delphinidin 3-rutinoside-5-glucoside and cyanidin 3-rutinoside dimer. The antioxidant activity and anti-diabetic potential of fractionated MP were analyzed in vitro and ex vivo with HepG2 and pancreatic β-cell RIN-m5F. Hierarchical cluster analysis and Pearson correlation coefficients revealed compounds such as syringic acid and galloylcyanidin-glycoside contributed most to inhibit α-glucosidase activity. Quercetin and cyanidin-glycosides were essential for cellular antioxidant activity. Dihydroquercetin and 1,5-dicaffeoylquinic acid were newly identified and validated as the main contributors after rutin to protect RIN-m5F cells against glucotoxicity. Such findings suggest the promising role of MP for type II diabetics and lay the foundation of further utilization and investigation.

Mulberry anthocyanin extract ameliorates insulin resistance by regulating PI3K/AKT pathway in HepG2 cells and db/db mice

This study evaluated the capacity of mulberry anthocyanin extract (MAE) on insulin resistance amelioration in HepG2 cells induced by high glucose and palmitic acid and diabetes-related metabolic changes in type 2 diabetic mice. In vitro, MAE alleviated insulin resistance in HepG2 cells and increased glucose consumption, glucose uptake and glycogen content. Enzyme activities of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) were decreased due to PPARγ coactivator 1α (PGC-1α) and forkhead box protein O1 (FOXO1) inhibition. Furthermore, phosphorylation of protein kinase B (AKT) and glycogen synthase kinase-3β (GSK3β) in model cells was recovered after treated with MAE, leading to an up-regulation of glycogen synthase 2 (GYS2), and this effect was blocked by the phosphatidylinositol-3-kinase (PI3K) inhibitor LY294002. In vivo, MAE supplementation (50 and 125 mg/kg body weight per day) markedly decreased fasting blood glucose, serum insulin, leptin, triglyceride and cholesterol levels and increased adiponectin levels in db/db mice. The improvement of related metabolic parameters was in part associated with the impact of MAE on activating AKT and downstream targets in liver, skeletal muscle and adipose tissues. In summary, these findings suggest that MAEs have potential benefits on improving dysfunction in diabetic mice and mitigating insulin resistance in HepG2 cells via activation of PI3K/AKT pathways.