Antidiabetic potential of dietary polyphenols: A mechanistic review

Advances of nanoparticle derived from food in the control of α-dicarbonyl compounds-A review

α-Dicarbonyl compounds (α-DCs) are predominantly generated through the thermal processing of carbohydrate and protein-rich food. They are pivotal precursors to hazard formation, such as advanced glycation end products (AGEs), acrylamide, and furan. Their accumulation within the body will be genotoxicity and neurotoxicity. Recently, significant advancements have been made in nanotechnology, leading to the widespread utilization of nanomaterials as functional components in addressing the detrimental impact of α-DCs. This review focuses on the control of α-DCs through the utilization of nanoparticle-based functional factors, which were prepared by using edible components as resources. Four emerging nanoparticles are introduced including phenolic compounds-derived nanoparticle, plant-derived nanoparticle, active peptides-derived nanoparticle, and functional minerals-derived nanoparticle. The general control mechanisms as well as the recent evidence pertaining to the aforementioned aspects were also discussed, hoping to valuable helpful references for the development of innovative α-DCs scavengers and identifying the further scope of research.

The Chemical Profiles and Antioxidant Properties of Live Fruit or Vegetable Vinegars Available on the Polish Food Market

Live vinegar is a product formed through a two-step fermentation process of a sugar substrate that has not been subjected to filtration or pasteurization. This is considered to preserve all nutrients and biologically active microorganisms, making it a product with a valuable composition and beneficial properties. Therefore, the purpose of this study was to analyze the chemical composition and antioxidant properties of the selected vinegars available on the Polish food market. The material in the study consisted of four live (naturally turbid, unfiltered, unpasteurized) fruit or vegetable vinegars: apple, pear, rhubarb, and lemon. Spectrophotometric, HPLC, and GC methods were used. Among the vinegars tested, lemon vinegar had the highest vitamin C content-15.95 mg/100 mL. Apple vinegar proved to be the best source of polyphenols and flavonoids (TPC-191.97 mg GAE/L, TFC-70.22 mg RE/L). All of the vinegars contained dihydroxybenzoic acid, 4-hydroxybenzoic acid, caffeic acid, 2-hydroxycinnamic acid, and myricetin. The acetic acid content of the tested vinegars ranged from 29.180 to 38.125 mM/L. The pH values ranged from 3.14 to 3.41. In conclusion, the most promising nutraceutical with potentially beneficial health-promoting properties seems to be apple vinegar.

An insight into the mechanistic role of (-)-Ampelopsin F from Vatica chinensis L. in inducing insulin secretion in pancreatic beta cells

Resveratrol oligomers, ranging from dimers to octamers, are formed through regioselective synthesis involving the phenoxy radical coupling of resveratrol building blocks, exhibiting remarkable therapeutic potential, including antidiabetic properties. In this study, we elucidate the mechanistic insights into the insulin secretion potential of a resveratrol dimer, (-)-Ampelopsin F (AmF), isolated from the acetone extract of Vatica chinensis L. stem bark in Pancreatic Beta-TC-6 cell lines. The AmF (50 µM) treated cells exhibited a 3.5-fold increase in insulin secretion potential as compared to unstimulated cells, which was achieved through the enhancement of mitochondrial membrane hyperpolarization, elevation of intracellular calcium concentration, and upregulation of GLUT2 and glucokinase expression in pancreatic Beta-TC-6 cell lines. Furthermore, AmF effectively inhibited the activity of DPP4, showcasing a 2.5-fold decrease compared to the control and a significant 6.5-fold reduction compared to the positive control. These findings emphasize AmF as a potential lead for the management of diabetes mellitus and point to its possible application in the next therapeutic initiatives.

Melon peel flour: utilization as a functional ingredient in bakery products

Food by-products are a major concern with a direct impact on the economy, society, and environment. The valorisation of these by-products could be an advantageous approach to face the increase in food waste since it can compromise environmental health and food sustainability. On the other hand, this valorisation would allow the development of new food products with health benefits for the population. Cucumis melo L. is a highly consumed fruit all over the world since it has excellent sensory and nutritional qualities, being also a good source of bioactive compounds. However, its peel and seeds are usually discarded. The aim of this study was to evaluate the potential of melon peel flour as a functional ingredient for innovative food products. For that, two different formulations containing melon peel flour were developed (a biscuit and a muffin) by replacing a conventional flour (wheat flour) in different percentages (50% and 100%, respectively). The nutritional composition, total phenolic content, and antioxidant potential of the developed products were studied, showing a high content of fibre, high levels of phenolic compounds and good sensory acceptability. These results show that it is possible to enrich different foods with melon peel flour in order to improve their nutritional properties, contributing to improving public health, simultaneously valorising a usually rejected by-product, reducing food waste and the environmental impact.

Comparison of the anti-diabetic effects of various grain and legume extracts in high-fat diet and streptozotocin-nicotinamide-induced diabetic rats

The anti-diabetic properties of whole groats and dietary fibers from various grains and legumes are well known. Nevertheless, studies on the anti-diabetic effects of their extracts are limited, and it is difficult to compare their efficacy. This study investigated the anti-diabetic potential of ethanol extracts from oats (OE), sorghum (SE), foxtail millet (FE), proso millet (PE), adzuki bean (AE), and black soybean (BE) in a high-fat diet and streptozotocin-nicotinamide-induced diabetic rat models. The extracts, obtained using 99.9 % ethanol, were orally administered to diabetic rats for four weeks. Various parameters were evaluated, including fasting blood glucose levels, glucose tolerance, insulin sensitivity, serum insulin levels, and pancreas histological analysis. OE and SE effectively reduced fasting blood glucose levels and the area under the curve (AUC) in the oral glucose tolerance test. Only OE significantly decreased the AUC in the insulin tolerance test and increased insulin concentration and homeostatic model assessment of the β-cell function index, indicating improved insulin sensitivity and β-cell function. Histological and immunohistochemical analysis of the pancreas supported these findings, demonstrating that OE protected against pancreatic cell damage. In contrast, FE, PE, AE, and BE did not have a significant effect on diabetes-related parameters. These findings identify OE as the most promising natural intervention for diabetes management.

Phenolic profile, acute and subacute oral toxicity of the aqueous extract from Moroccan Mentha longifolia L. aerial part in Swiss Albino mice model

ETHNOPHARMACOLOGICAL RELEVANCE

Mentha longifolia (L.) (Lamiaceae) is a native plant in Morocco, traditionally used in different countries to treat several disorders notably gastrointestinal illnesses, respiratory disorders, infectious diseases, inflammatory diseases, and menstrual problems. Robust scientific evidence has confirmed multiple pharmacological properties of M. longifolia including antihemolytic, anti-inflammatory, antibacterial, hepatoprotective, anti-cancer, antidiabetic, gastroprotective effect, and antispasmodic activity.

AIM OF THE STUDY

The current study aimed to determine the phytochemical profile and assess the toxic effect of an aqueous extract of the arial parts of M. longifolia in male and female Swiss albino mice during acute and subacute oral toxicity.

MATERIALS AND METHODS

High-performance Liquid Chromatography Diode Array Detector (HPLC-DAD) was used to provide qualitative and quantitative analyses of phenolic compounds of M. longifolia aqueous extract. In acute toxicity experiments, four distinct groups of mice (n = 5/group/sex) were administered Mentha longifolia aqueous extract at single oral dosages of 0.5; 1; 2; 4, and 8 g/kg BW given by gavage and intraperitoneal for up to 14 days. Regarding the subacute toxicity investigation, Swiss albino mice were given M. longifolia aqueous extract orally at dosages of 100; 500; and 1000 mg/kg BW daily for 28 days. Body weight is measured every 7 days and suggested biochemical and hematological parameters were quantified, at the finish of 28 days of daily administration, sections of the liver, kidney, and spleen were histologically evaluated for showing damage to organs.

RESULTS

The data of High-performance Liquid chromatography analysis revealed that M. longifolia aqueous extract was rich in interesting phytochemical compounds, mainly quercetin, and rutin, followed by a hydroxybenzoic acid-like syringic acid. Regarding the acute test in mice, no mortality or symptoms of toxicity were detected following oral administration with a single dose of M. longifolia aqueous extract at any dosage limit up to 4 g/kg, which was the no-observed side effect threshold (NOAEL). The mortality rate as well as acute toxicity of the M. longifolia aqueous extract delivered intraperitoneally, are increased progressively with increasing dosage. The non-observed adverse effect level (NOAEL) for the intraperitoneal dosage was 1 g/kg BW, and the lowest observed adverse effect level (LOAEL) was 2 g/kg BW, the estimated acute toxicity (LD50) of intraperitoneally given M. longifolia aqueous extract in mice was 4.800 g/kg BW. Concerning subacute examinations in mice, the M. longifolia aqueous extract did not induce substantial modifications in biochemical or hematological indicators, preserving a slight increase in creatinine and urea levels. At the end of the experiment, a histopathological examination of the kidneys, liver, and spleen revealed normal architecture, suggesting no morphological damage.

CONCLUSION

The data we obtained indicate that acute or subacute administration of Mentha longifolia aqueous extract is relatively non-toxic in male and female Swiss albino mice.

Flours from Spondias mombin and Spondias tuberosa seeds: Physicochemical characterization, technological properties, and antioxidant, antibacterial, and antidiabetic activities

Yellow mombin (Spondias mombin) and Brazil plum (Spondias tuberosa) seeds are byproducts of exploiting their pulp and currently have no relevant food or industrial applications. Thus, the present study aimed to evaluate the physicochemical, technological, and functional characteristics of flours obtained from yellow mombin (YMF) and Brazil plum (BPF) residues. The flours presented a high percentage of insoluble fiber (68.8-70.2 g/100 g) and low carbohydrate (2.7-4.0 g/100 g) and caloric (91.9-95.3 kcal) values. The flours showed potential for technological application. In addition, the highest concentration of total phenolic content (31.1-50.2 mg GAE/g) was obtained with 70% acetone, which provided excellent results for antioxidant capacity evaluated by 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (81.0%-89.7%) and 2,2-diphenyl-1-picrylhydrazyl (60.6%-69.1%) radical scavenging capacity assays. Flour extracts in 70% acetone also exhibited inhibition of α-amylase (63.3%-78.8%) and amyloglucosidase (63.5%-71.0%). The antibacterial study revealed that extracts inhibited the growth of Escherichia coli, Burkholderia cepacia, and Burkholderia multivorans. Therefore, this study suggests the use of yellow mombin and Brazil plum residues for different food or industrial applications. PRACTICAL APPLICATION: The knowledge gained from this study will open a new approach to add value to yellow mombin and Brazil plum fruit seeds as sources of fiber and bioactive compounds, with promising application in the formulation of functional and nutraceutical products, benefiting both a sustainable environment and a sustainable industry.

Potential roles of cereal bioactive compounds in the prevention and treatment of type 2 diabetes: A review of the current knowledge

Diabetes is one of the most common non-communicable diseases in both developed and underdeveloped countries with a 9.3% prevalence. Unhealthy diets and sedentary lifestyles are among the most common reasons for type 2 diabetes mellitus (T2DM). Diet plays a crucial role in both the etiology and treatment of T2DM. There are several recommendations regarding the carbohydrate intake of patients with T2DM. One of them is about reducing the total carbohydrate intake and/or changing the type of carbohydrate to reduce the glycaemic index. Cereals are good sources of carbohydrates in the diet with a significant amount of soluble and non-soluble fiber content. Apart from fiber, it has been shown that the bioactive compounds present in cereals such as proteins, phenolic compounds, carotenoids, and tocols have beneficial impacts in the prevention and treatment of T2DM. Moreover, cereal by-products especially the by-products of milling processes, which are bran and germ, have been reported to have anti-diabetic activities mainly because of their fiber and polyphenols content. Considering the potential functions of cereals in patients with T2DM, this review focuses on the roles of cereal bioactive compounds in the prevention and treatment of type 2 diabetes.

Identification of Polyphenols in Sea Fennel (Crithmum maritimum) and Seaside Arrowgrass (Triglochin maritima) Extracts with Antioxidant, ACE-I, DPP-IV and PEP-Inhibitory Capacity

Sea fennel and seaside arrowgrass are two abundant but underutilized halophytes along the Atlantic and Mediterranean coasts. This study investigated the antioxidant capacity and the potential antihypertensive (Angiotensin Converting Enzyme I, ACE-I inhibition), hypoglycaemic (Dipeptidyl Peptidase IV, DPP-IV inhibition), and nootropic (Prolyl Endopeptidase, PEP inhibition) activity of their polyphenol extracts. They had a high phenol content (21-24 mEq GA/g), antioxidant capacity evaluated using the ABTS (17-2 mg ascorbic acid/g) and FRAP (170-270 mM Mohr's salt/g) assays, and effective ACE-inhibiting properties (80-90% inhibiting activity at final concentration of 0.5 mg/mL). Additionally, the sea fennel extract displayed high DPP-IV inhibitory capacity (73% at 1 mg/mL), while the seaside arrowgrass extract exhibited potent Prolyl endopeptidase inhibitory capacity (75% at 1 mg/mL). Fractionation by HPLC concentrated the bioactive molecules in two fractions, for which the composition was analyzed by LC-MS/MS. Different chlorogenic acids seemed to play an important role in the bioactivity of sea fennel extract, and different flavonoids, mainly apigenin, luteolin and chrysoeriol, in the bioactivity of the seaside arrowgrass extract. Given their potential health benefits, these extracts could serve as valuable bioactive ingredients and could potentially encourage the cultivation of these species in regions where traditional crops face challenges in growth.

New anti-α-Glucosidase and Antioxidant Ingredients from Winery Byproducts: Contribution of Alkyl Gallates

Wine-making activity entails the production of solid and semisolid byproducts (grape stems and pomace and wine lees) that negatively impact the environment and industrial sustainability. Their features as sources of bioactive compounds support valorization procedures for functional and healthy ingredients. This work uncovers the quantitative alkyl gallates (gallic acid esters, C1-C12) profile of fresh (freeze-dried) materials and the effect of oven-drying on their stability by UHPLC-ESI-QqQ-MS/MS. The functionality was established concerning DPPH• scavenging and antihyperglycemic power. Wine lees exerted the highest high-free concentration of galloyl derivatives, ethyl gallate being the most abundant ester (3472.62 ng/g dw, on average). About the impact of the stabilization process, although as a general trend, the thermal treatment reduced the concentration, the reduction dimensions depended on the compound/matrix, remaining in valuable concentrations. Concerning radical scavenging, ze-dried stems and pomace displayed the highest capacity (24.11 and 18.46 mg TE/g dw, respectively), being correlated with propyl gallate (r2 = 0.690), butyl gallate (r2 = 0.686), and octyl gallate (r2 = 0.514). These two matrices exerted α-glucosidase inhibitory activity (1.58 and 1.46 units/L) equivalent to that of acarbose (a recognized α-glucosidase inhibitor). The newly described bioactive phytochemicals in winery residues (galloyl esters) and their correlation with functional traits allow for envisioning valorization alternatives.

Two polysaccharides from Rehmannia glutinosa: isolation, structural characterization, and hypoglycemic activities

Rehmannia glutinosa (RG) as a Chinese herbal medicine can be used both in medicine and food. As the main component of RG, the polysaccharides have a hypoglycemic effect, however, the hypoglycemic activity of RG homopolysaccharides remains unknown. We isolated and purified two polysaccharides, RGP70-1-1 and RGP70-1-2 (4.9 kDa and 2.8 kDa) from RG. The structural characteristics, including monosaccharide composition, linkage, and configuration were analyzed by FT-IR, HPLC, GC-MS, NMR spectroscopy, Congo test, and SEM. RGP70-1-1 and RGP70-1-2 consist of four monosaccharides (glucose, mannose, arabinose, and galactose). RGP70-1-1 contains 14 connection modes, with the linkages including l-Araf-(1→, →3)-l-Araf-(1→, →5)-l-Araf-(1→, →3,5)-l-Araf-(1→, →2,5)-l-Araf-(1→, d-Manp-(1→, →2)-d-Manp-(1→, →4)-d-Manp-(1→, d-Galp-(1→, →4)-d-Galp-(1→, →4,6)-d-Galp-(1→, →6)-d-Glcp-(1→, →4,6)-d-Glcp-(1→, →3,6)-d-Glcp-(1→. The linkages of RGP70-1-2 is including →5)-l-Araf-(1→, →3,5)-l-Araf-(1→, →4)-d-Manp-(1→, →3,6)-d-Manp-(1→, d-Galp-(1→, →6)-d-Galp-(1→, d-Glcp-(1→, →6)-d-Glcp-(1→, →4,6)-d-Glcp-(1→. Furthermore, RGP70-1-1 and RGP70-1-2 can inhibit α-glucosidase and α-amylase. RGP70-1-1 stimulated GLP-1 secretion in STC-1 cells and was related to the up-regulation of PI3K and p-AKT protein expression. The findings revealed a natural product with potential hypoglycemic activity, which may be used as a GLP-1 secretagogue and a beneficial functional food ingredient for T2D.

Impact of Polyphenols on Inflammatory and Oxidative Stress Factors in Diabetes Mellitus: Nutritional Antioxidants and Their Application in Improving Antidiabetic Therapy

Diabetes mellitus is a chronic metabolic disorder characterized by hyperglycaemia and oxidative stress. Oxidative stress plays a crucial role in the development and progression of diabetes and its complications. Nutritional antioxidants derived from dietary sources have gained significant attention due to their potential to improve antidiabetic therapy. This review will delve into the world of polyphenols, investigating their origins in plants, metabolism in the human body, and relevance to the antioxidant mechanism in the context of improving antidiabetic therapy by attenuating oxidative stress, improving insulin sensitivity, and preserving β-cell function. The potential mechanisms of, clinical evidence for, and future perspectives on nutritional antioxidants as adjuvant therapy in diabetes management are discussed.

Cardiometabolic Risk: Characteristics of the Intestinal Microbiome and the Role of Polyphenols

Cardiometabolic diseases like hypertension, type 2 diabetes mellitus, atherosclerosis, and obesity have been associated with changes in the gut microbiota structure, or dysbiosis. The beneficial effect of polyphenols on reducing the incidence of this chronic disease has been confirmed by numerous studies. Polyphenols are primarily known for their anti-inflammatory and antioxidant properties, but they can also modify the gut microbiota. According to recent research, polyphenols positively influence the gut microbiota, which regulates metabolic responses and reduces systemic inflammation. This review emphasizes the prebiotic role of polyphenols and their impact on specific gut microbiota components in patients at cardiometabolic risk. It also analyzes the most recent research on the positive effects of polyphenols on cardiometabolic health. While numerous in vitro and in vivo studies have shown the interaction involving polyphenols and gut microbiota, additional clinical investigations are required to assess this effect in people.

Research Progress of α-Glucosidase Inhibitors Produced by Microorganisms and Their Applications

Based on the easy cultivation of microorganisms and their short cycle time, research on α-glucosidase inhibitors (α-GIs) of microbial origin is receiving extensive attention. Raw materials used in food production, such as cereals, dairy products, fruits, and vegetables, contain various bioactive components, like flavonoids, polyphenols, and alkaloids. Fermentation with specific bacterial strains enhances the nutritional value of these raw materials and enables the creation of hypoglycemic products rich in diverse active ingredients. Additionally, conventional food processing often results in significant byproduct generation, causing resource wastage and environmental issues. However, using bacterial strains to ferment these byproducts into α-GIs presents an innovative solution. This review describes the microbial-derived α-GIs that have been identified. Moreover, the production of α-GIs using industrial food raw materials and processing byproducts as a medium in fermentation is summarized. It is worth analyzing the selection of strains and raw materials, the separation and identification of key compounds, and fermentation broth research methods. Notably, the innovative ideas in this field are described as well. This review will provide theoretical guidance for the development of microbial-derived hypoglycemic foods.

The Protective Role of Dietary Polyphenols in Urolithiasis: Insights into Antioxidant Effects and Mechanisms of Action

Urolithiasis is a common urological disease with increasing prevalence and high recurrence rates around the world. Numerous studies have indicated reactive oxygen species (ROS) and oxidative stress (OS) were crucial pathogenic factors in stone formation. Dietary polyphenols are a large group of natural antioxidant compounds widely distributed in plant-based foods and beverages. Their diverse health benefits have attracted growing scientific attention in recent decades. Many literatures have reported the effectiveness of dietary polyphenols against stone formation. The antiurolithiatic mechanisms of polyphenols have been explained by their antioxidant potential to scavenge free radicals and ROS, modulate the expression and the activity of endogenous antioxidant and prooxidant enzymes, regulate signaling pathways associated with OS, and maintain cell morphology and function. In this review, we first describe OS and its pathogenic effects in urolithiasis and summarize the classification and sources of dietary polyphenols. Then, we focus on the current evidence defining their antioxidant potential against stone formation and put forward challenges and future perspectives of dietary polyphenols. To conclude, dietary polyphenols offer potential applications in the treatment and prevention of urolithiasis.

Evaluation of α-Glucosidase Inhibition and Antihyperglycemic Activity of Extracts Obtained from Leaves and Flowers of Rumex crispus L

Among antihyperglycemic drugs used for treating diabetes, α-glucosidase inhibitors generate the least adverse effects. This contribution aimed to evaluate the potential antidiabetic activity of Rumex crispus L. by testing its in vitro α-glucosidase inhibition and in vivo antihyperglycemic effects on rats with streptozotocin (STZ)-induced diabetes. Better inhibition of α-glucosidase was found with the methanol extract versus the n-hexane and dichloromethane extracts. The methanol extract of the flowers (RCFM) was more effective than that of the leaves (RCHM), with an IC50 of 7.3 ± 0.17 μg/mL for RCFM and 112.0 ± 1.23 μg/mL for RCHM. A bioactive fraction (F89s) also showed good α-glucosidase inhibition (IC50 = 3.8 ± 0.11 μg/mL). In a preliminary study, RCHM and RCFM at 150 mg/kg and F89s at 75 mg/kg after 30 days showed a significant effect on hyperglycemia, reducing glucose levels (82.2, 80.1, and 84.1%, respectively), and improved the lipid, renal, and hepatic profiles of the rats, comparable with the effects of metformin and acarbose. According to the results, the activity of R. crispus L. may be mediated by a diminished rate of disaccharide hydrolysis, associated with the inhibition of α-glucosidase. Thus, R. crispus L. holds promise for the development of auxiliary drugs to treat diabetes mellitus.

Pseudobombax parvifolium Hydroalcoholic Bark Extract: Chemical Characterisation and Cytotoxic, Mutagenic, and Preclinical Aspects Associated with a Protective Effect on Oxidative Stress

Plants have long been used in traditional medicine to treat illnesses. Nevertheless, their chemical diversity requires studies to establish the extract dosage and its safe use. Pseudobombax parvifolium, an endemic species of the Brazilian Caatinga biome, is commonly used in folk medicine, due to its anti-inflammatory properties related to cellular oxidative stress; however, its biological properties have scarcely been studied. In this study, we chemically characterized the P. parvifolium hydroalcoholic bark extract (EBHE) and evaluated its cytotoxic, mutagenic, and preclinical aspects, as well as its antioxidant effect. Our phytochemical analysis revealed a significative total polyphenol content and identified loliolide for the first time in this species. Cytotoxicity, mutagenicity, and acute oral and repeated dose indicated no toxic effects on cell culture, Drosophila melanogaster, and Wistar rat exposure to different EBHE concentrations, respectively. Furthermore, we observed a significant decrease in lipid peroxidation and a mild hypoglycemic and hypolipidemic effect with repeated oral dosing of EBHE. Although there were no significant changes in glutathione content, we did observe a significant increase in superoxide dismutase at a dose of 400 mg/kg and in glutathione peroxidase at doses of 100, 200, and 400 mg/kg. These findings suggest that EBHE has potential as a source of bioactive molecules, and it can be used safely in traditional medicine and in the development of herbal medicines for application in the public health system.

Nanoformulations for the Delivery of Dietary Anthocyanins for the Prevention and Treatment of Diabetes Mellitus and Its Complications

Diabetes mellitus (DM) is a metabolic disease characterized by abnormal blood glucose levels-hyperglycemia, caused by a lack of insulin secretion, impaired insulin action, or a combination of both. The incidence of DM is increasing, resulting in billions of dollars in annual healthcare costs worldwide. Current therapeutics aim to control hyperglycemia and reduce blood glucose levels to normal. However, most modern drugs have numerous side effects, some of which cause severe kidney and liver problems. On the other hand, natural compounds rich in anthocyanidins (cyanidin, delphinidin, malvidin, pelargonidin, peonidin, and petunidin) have also been used for the prevention and treatment of DM. However, lack of standardization, poor stability, unpleasant taste, and decreased absorption leading to low bioavailability have hindered the application of anthocyanins as therapeutics. Therefore, nanotechnology has been used for more successful delivery of these bioactive compounds. This review summarizes the potential of anthocyanins for the prevention and treatment of DM and its complications, as well as the strategies and advances in the delivery of anthocyanins using nanoformulations.

Polyphenols and Cardiometabolic Health: Knowledge and Concern among Romanian People

The cardiometabolic health of the population is a crucial indicator of public health, considering the significant impact of cardiovascular disease (CVD) and diabetes on global mortality. Determining the population's knowledge and the predictors of these pathologies is essential in developing effective educational and clinical strategies for the prevention and management of cardiometabolic risk (CMR). Polyphenols are natural compounds with a multitude of beneficial effects on cardiometabolic health. This study explored the current knowledge, understanding, and awareness of CMR, the benefits of polyphenols among Romanians, and how sociodemographic and clinical characteristics influence this aspect. Five hundred forty-six subjects responded anonymously to an online questionnaire designed to assess their knowledge. The data were collected and analyzed based on gender, age, education level, and BMI status. Most respondents expressed concern to a great or very great extent about their health (78%) and food (60%), with significant differences (p < 0.05) depending on age, educational level, and BMI status. Of the respondents, 64.8% declared that they were familiar with the CMR term. Still, the results showed a weak correlation between the stated risk factors and the self-assessment of increased risk (r = 0.027) for CVD or diabetes. Only 35% of the respondents reported a good or very good knowledge of the term "polyphenols", 86% recognized the antioxidant effect, and significantly fewer (26%) recognized the prebiotic effect. Developing and implementing targeted educational strategies to enhance learning and individual behaviors related to CMR factors and the benefits of polyphenols is necessary.

Phenolic Phytochemicals for Prevention and Treatment of Colorectal Cancer: A Critical Evaluation of In Vivo Studies

Colorectal cancer (CRC) is the third most diagnosed and second leading cause of cancer-related death worldwide. Limitations with existing treatment regimens have demanded the search for better treatment options. Different phytochemicals with promising anti-CRC activities have been reported, with the molecular mechanism of actions still emerging. This review aims to summarize recent progress on the study of natural phenolic compounds in ameliorating CRC using in vivo models. This review followed the guidelines of the Preferred Reporting Items for Systematic Reporting and Meta-Analysis. Information on the relevant topic was gathered by searching the PubMed, Scopus, ScienceDirect, and Web of Science databases using keywords, such as "colorectal cancer" AND "phenolic compounds", "colorectal cancer" AND "polyphenol", "colorectal cancer" AND "phenolic acids", "colorectal cancer" AND "flavonoids", "colorectal cancer" AND "stilbene", and "colorectal cancer" AND "lignan" from the reputed peer-reviewed journals published over the last 20 years. Publications that incorporated in vivo experimental designs and produced statistically significant results were considered for this review. Many of these polyphenols demonstrate anti-CRC activities by inhibiting key cellular factors. This inhibition has been demonstrated by antiapoptotic effects, antiproliferative effects, or by upregulating factors responsible for cell cycle arrest or cell death in various in vivo CRC models. Numerous studies from independent laboratories have highlighted different plant phenolic compounds for their anti-CRC activities. While promising anti-CRC activity in many of these agents has created interest in this area, in-depth mechanistic and well-designed clinical studies are needed to support the therapeutic use of these compounds for the prevention and treatment of CRC.

The α-Amylase and α-Glucosidase Inhibition Capacity of Grape Pomace: A Review

The concept of functional foods is gaining more importance due to its role in maintaining a healthy status and preventing some metabolic diseases. The control of diabetes, in particular type-2 (T2DM), could be considered a big challenge since it involves other factors such as eating habits. From the pharmacological point of view, inhibiting digestive enzymes, such as α-amylase and α-glucosidase, is one of the mechanisms mainly used by synthetic drugs to control this disease; however, several side effects are described. For that reason, using bioactive compounds may appear as an alternative without presenting the complications synthetic drugs available on the market have. The winemaking industry generates tons of waste annually, and grape pomace (GP) is the most important. GP is recognized for its nutritional value and as a source of bioactive compounds that are helpful for human health. This review highlights the importance of GP as a possible source of α-amylase and α-glucosidase inhibitors. Also, it is emphasized the components involved in this bioactivity and the possible interactions among them. Especially, some phenolic compounds and fiber of GP are the main ones responsible for interfering with the human digestive enzymes. Preliminary studies in vitro confirmed this bioactivity; however, further information is required to allow the specific use of GP as a functional ingredient inside the market of products recommended for people with diabetes.

Graphical abstract

Citrus flavanone metabolites protect pancreatic β-cells against cholesterol stress through a multi-proteomic mechanism

Citrus flavanones may improve oxidative stress and insulin resistance induced by western diets. However, there is a paucity of studies investigating the change in protein expression levels. This study evaluated the protection and the mechanisms of action of citrus flavanone metabolites, hesperetin 7-glucuronide (H7G) and 3-(4'-hydroxyphenyl) propanoic acid (PA), on pancreatic β-cell function under oxidative stress induced by cholesterol using the global proteomics approach. Cholesterol induced changes in the global proteomic profile in the pancreatic β-cell line Min6. On the other hand, proteomics analysis identified 254 proteins differentially expressed with H7G and 352 with PA treatments, most of them were opposite to the changes induced by cholesterol. Bioinformatics analysis showed that these proteins are implicated in cell functions like cell signaling (insulin signaling, p30MAPK signaling, and others), metabolism (glucokinase and glutathione metabolisms), and inflammation pathways (TNF-α and NF-κB pathways). Also, the results of molecular docking suggest that H7G and PA could bind to putative transcription factors (PPAR-γ, STAT-3, CREB1, NF-κB, NFYA) and cell signaling proteins (IKK, RAS, Pi3K, ERK), which results in changes in protein expression observed. Altogether, these data suggest that the treatment with H7G and PA protects pancreatic β-cells against stress induced by cholesterol through multi-proteomic mechanisms of action.

Dietary polyphenols and their relationship to the modulation of non-communicable chronic diseases and epigenetic mechanisms: A mini-review

Chronic Non-Communicable Diseases (NCDs) have been considered a global health problem, characterized as diseases of multiple factors, which are developed throughout life, and regardless of genetics as a risk factor of important relevance, the increase in mortality attributed to the disease to environmental factors and the lifestyle one leads. Although the reactive species (ROS/RNS) are necessary for several physiological processes, their overproduction is directly related to the pathogenesis and aggravation of NCDs. In contrast, dietary polyphenols have been widely associated with minimizing oxidative stress and inflammation. In addition to their antioxidant power, polyphenols have also drawn attention for being able to modulate both gene expression and modify epigenetic alterations, suggesting an essential involvement in the prevention and/or development of some pathologies. Therefore, this review briefly explained the mechanisms in the development of some NCDs, followed by a summary of some evidence related to the interaction of polyphenols in oxidative stress, as well as the modulation of epigenetic mechanisms involved in the management of NCDs.

The anti-diabetic activity of polyphenols-rich vinegar extract in mice via regulating gut microbiota and liver inflammation

Polyphenols in vinegar are benefit to human health. The purpose of this research was to identify the polyphenols-rich vinegar extract (VE) and evaluate the anti-diabetic mechanisms in vivo. The results showed that 29 polyphenols were identified by UPLC-Q/Trap-MS/MS analysis. 4-Hydroxybenzoic acid, ferulic acid, and ethyl ferulate were the main polyphenols. In addition, VE relieved the symptoms of type 2 diabetes mellitus (T2DM) by down-regulating blood glucose and lipemia. VE reduced inflammation by inhibiting TLR4/NF-κB signaling pathway. Furthermore, VE treatment restored gut microbiota dysbiosis (upregulating Bacteroidetes, Lactobacillus, Bifidobacterium, and Bacteroides and downregulating Firmicutes, Proteobacteria, and Enterorhabdus abundances), and increased short chain fatty acids contents in diabetic mice, which participated in anti-diabetic effect of VE by correlation analysis. These findings suggest that VE may be a candidate for T2DM intervention by regulating gut microbiota and inflammation.

Polyphenols in Metabolic Diseases

Polyphenols (PPs) are a large group of phytochemicals containing phenolic rings with two or more hydroxyl groups. They possess powerful antioxidant properties, multiple therapeutic effects, and possible health benefits in vivo and in vitro, as well as reported clinical studies. Considering their free-radical scavenging and anti-inflammatory properties, these substances can be used to treat different kinds of conditions associated with metabolic disorders. Many symptoms of metabolic syndrome (MtS), including obesity, dyslipidemia, atherosclerosis, elevated blood sugar, accelerating aging, liver intoxication, hypertension, as well as cancer and neurodegenerative disorders, are substantially relieved by dietary PPs. The present study explores the bioprotective properties and associated underlying mechanisms of PPs. A detailed understanding of these natural compounds will open up new opportunities for producing unique natural PP-rich dietary and medicinal plans, ultimately affirming their health benefits.

Household Processing Methods and Their Impact on Bioactive Compounds and Antioxidant Activities of Sweetpotato Genotypes of Varying Storage Root Flesh Colours

Sweetpotato storage roots, peeled and unpeeled, of varying flesh colours (white, cream, yellow, pale orange, deep orange, and purple) were spectrophotometrically evaluated for their bioactive compounds and antioxidant activities. Roots were boiled, steamed, baked, fried, or microwaved. The unpeeled roots had relatively higher (p < 0.001) bioactive compounds and antioxidant activities than the peeled ones. All cooking methods increased phenolic compounds, flavonoids, and tannins in all genotypes. Significant losses of total carotenoids occurred with all cooking methods (ranging from 24.18 to 172.76 µg/g in raw sweetpotatoes vs. 10.06 to 118.17 µg/g in cooked ones; p < 0.001), except the deep-orange-fleshed genotype, in which frying slightly increased carotenoids from 269.81 to 304.74 µg/g. Microwaving retained 69% vitamin C in the cream-fleshed one, the highest among the cooking methods. Anthocyanins decreased with baking and frying in the purple-fleshed one but increased with other methods; microwaving being highest at 13.9% (17.43 mg/g). While the 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid antioxidant activity decreased with all cooking techniques in some genotypes, ferricyanide-reducing antioxidant potential increased. The retention of bioactive compounds in sweetpotato storage roots depends on the processing method. Thus, to obtain the most health benefits, consumers should use different cooking methods but retain the peels.

In Vitro and In Vivo Digestive Fate and Antioxidant Activities of Polyphenols from Hulless Barley: Impact of Various Thermal Processing Methods and β-Glucan

The unfavorable bioaccessibility of polyphenols in cereal-based food limits their physiological functions as most polyphenols bind spontaneously to the cell-wall polysaccharides. Effects of β-glucan and various thermal processing methods including flaking and roasting, stir-frying, steam-flash explosion, and popping expansion on the bioaccessibility and antioxidant properties of polyphenols from hulless barley in vitro and in vivo were investigated in this study. The bioaccessibility and antioxidant capacity (via DPPH, ·OH, and ·O₂^- free radical scavenging, TAC, and FRAP assays) of polyphenol extracts from hulless barley treated by steam-flash explosion and popping expansion increased significantly before and after in vitro digestion compared to those from raw and other processed hulless barley. Further, the total polyphenol content of hulless barley elevated dramatically following hydrolyzing with β-glucanase, which was positively correlated with the antioxidant activity. Additionally, the hulless barley treated with steam-flash explosion exhibited potent antidiabetic effects and antioxidant capacity (via TAC, SOD, GSH-Px, CAT, and MDA assays) in type 2 diabetic rats. The absorption of individual phenolic compounds in the alimentary canal of rats was impacted obviously by thermal processing. This study provides new insights into enhancing the bioaccessibility of the polyphenols and suggests that β-glucans interact with polyphenols and proteins in the hulless barley matrix.

Antioxidant, Antihypertensive, Hypoglycaemic and Nootropic Activity of a Polyphenolic Extract from the Halophyte Ice Plant (Mesembryanthemum crystallinum)

This study aims to determine the potential antioxidant, antihypertensive, hypoglycaemic and nootropic activity of a purified polyphenolic extract from the halophyte ice plant (Mesembryanthemum crystallinum). The ice plant extract showed good antioxidant activity measured by DPPH, ORAC, TEAC, FRAP and ferrous ion chelating activity. Moreover, the extract showed potent ACE, DPP-IV and PEP-inhibitory activity (90.5%, 98.6% and 73.1%, respectively, at a final concentration of 1 mg/mL). The extract was fractionated and the fraction with the highest content of total phenolic compounds showed the highest bioactivity, suggesting that polyphenols could be mainly responsible for the abovementioned activities. The tentative polyphenol identification by HPLC-ESI-QTOF-MS in this fraction revealed that flavones (>65%) are the major group, with apigenin (38%) predominating, followed by diosmin (17.7%) and luteolin (11.9%). They could presumably be the main elements responsible for the enzymatic inhibition activity. Additionally, 4-hydroxybenzoic acid, p-coumaric acid and a hydroxycinnamic acid derivative (2-O-(p-cumaroyl)-l-malic acid) were found in the extract. To our knowledge, this is the first time that some of these activities have been reported for halophyte extracts.

Cherries and Blueberries-Based Beverages: Functional Foods with Antidiabetic and Immune Booster Properties

Nowadays, it is largely accepted that the daily intake of fruits, vegetables, herbal products and derivatives is an added value in promoting human health, given their capacity to counteract oxidative stress markers and suppress uncontrolled pro-inflammatory responses. Given that, natural-based products seem to be a promising strategy to attenuate, or even mitigate, the development of chronic diseases, such as diabetes, and to boost the immune system. Among fruits, cherries and blueberries are nutrient-dense fruits that have been a target of many studies and interest given their richness in phenolic compounds and notable biological potential. In fact, research has already demonstrated that these fruits can be considered functional foods, and hence, their use in functional beverages, whose popularity is increasing worldwide, is not surprising and seem to be a promising and useful strategy. Therefore, the present review reinforces the idea that cherries and blueberries can be incorporated into new pharmaceutical products, smart foods, functional beverages, and nutraceuticals and be effective in preventing and/or treating diseases mediated by inflammatory mediators, reactive species, and free radicals.

Licania rigida leaf extract: Protective effect on oxidative stress, associated with cytotoxic, mutagenic and preclinical aspects

Brazilian plant biodiversity is a rich alternative source of bioactive compounds since plant-derived extracts and/or their secondary metabolites exhibit potential properties to treat several diseases. In this context, Licania rigida Benth (Chrysobalanaceae Family), a large evergreen tree distributed in Brazilian semi-arid regions, deserves attention for its widespread use in popular medicine, although its biological properties are still poorly studied. The aim of this study was to examine (1) acute and sub-chronic oral toxicity at 2000 mg/kg dose; (2) in vitro cytotoxicity at 0.1; 1; 10; 100 or 1000 µg/ml; (3) in vivo mutagenicity at 5, 10 or 20 mg/ml, and (4) potential antioxidant protective effect of L. rigida aqueous leaf extract of (AELr). No marked apparent toxic and genotoxic effects were observed using in vitro and in vivo assays after in vitro treatment of Chinese hamster ovary cell line (CHO-K1) with AELr or in vivo exposure of Wistar rats and Drosophila melanogaster to different extract concentrations. Concerning the antioxidant effect, the extract exhibited a protective effect by decreasing lipid peroxidation as determined by malondialdehyde levels. No significant changes were observed for glutathione (GSH) levels and activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx). Data demonstrate the beneficial potential of AELr to be employed for therapeutic purposes. However, further studies are required to validate the pharmacological application of this plant extract to develop as a phytotherapeutic formulation.

Cooking and In Vitro Digestion Modulate the Anti-Diabetic Properties of Red-Skinned Onion and Dark Purple Eggplant Phenolic Compounds

The intake of phenolic-rich foods is an emerging preventive approach for the management of type 2 diabetes, thanks to the ability of these compounds to inhibit some key metabolic enzymes. In this study, the influence of cooking and in vitro digestion on the α-glucosidase, α-amylase, and dipeptidyl-peptidase IV (DPP-IV) inhibitory activity of red-skinned onion (RSO) and dark purple eggplant (DPE) phenolic fractions was assessed. The applied cooking procedures had different influences on the total and individual phenolic compounds gastrointestinal bioaccessibility. DPE in vitro digested phenolic fractions displayed no inhibitory activity versus α-amylase and DPP-IV, whereas the fried DPE sample exhibited moderate inhibitory activity against α-glucosidase. This sample mainly contained hydroxycinnamic acid amides that can be responsible for the observed effect. Contrariwise, raw and cooked in vitro digested RSO phenolic fractions inhibited all three enzymes but with different effectiveness. Fried and raw RSO samples were the most active against them. Statistical analysis pointed out that quercetin mono-hexosides (mainly quercetin-4′-O-hexoside) were responsible for the inhibition of α-glucosidase, whereas quercetin di-hexosides (mainly quercetin-3-O-hexoside-4′-O-hexoside) were responsible for the DPP-IV-inhibitory activity of RSO samples. An accurate design of the cooking methods could be essential to maximize the release of individual phenolic compounds and the related bioactivities.

A Systematic Review of the Cardiometabolic Benefits of Plant Products Containing Mixed Phenolics and Polyphenols in Postmenopausal Women: Insufficient Evidence for Recommendations to This Specific Population

Menopause is characterized by endocrine and physiological changes and is often accompanied by increased body weight and cholesterol, glucose intolerance, and/or hypertension. These alterations are associated with increased risk for cardiovascular diseases (CVDs) and Type II diabetes mellitus (T2DM) that may be moderate by dietary plant phenolic compounds. In this review, we examine the current evidence of the impact of a variety of plant products (foods, extracts, beverages) rich in a mixture of phenolics and polyphenols on: (i) glucose and insulin levels; (ii) lipid profile; (iii) blood pressure; and (iv) biomarkers of inflammation and oxidative stress in postmenopausal women. We critically evaluate both the results of a range of intervention studies conducted in this specific subpopulation and the level of evidence supporting the benefits of consuming those products after the menopause. Overall, the current available evidence does not allow for specific dietary recommendations of these plant products rich in phenolics and polyphenols in this high-risk subpopulation. Our data show rather variable and small effects of the different products examined on the cardiometabolic biomarkers and further support the need to: (1) improve the quality of the study designs and data reporting; and (2) understand the variability in the response of the different biomarkers and establish clear differences between healthy and cardiometabolic disease levels.