Blueberry intake alters skeletal muscle and adipose tissue peroxisome proliferator-activated receptor activity and reduces insulin resistance in obese rats

Diet-Induced Rodent Obesity Is Prevented and the Fecal Microbiome Is Improved with Elderberry (Sambucus nigra ssp. canadensis) Juice Powder

Anthocyanin-rich edible berries protect against diet-induced obesity in animal models. Prevention is mediated through the bidirectional relationship with the fecal microbiome, and gut-derived phenolic metabolite absorption increases with physical activity, which may influence bioactivity. The objective of this study was to test elderberry juice powder on the development of diet-induced obesity and its influence on the fecal microbiome alone or in combination with physical activity. Male C57BL/6J mice were assigned to one of four treatments, including (1) high-fat diet without wheel access; (2) high-fat diet with unlimited wheel access; (3) high-fat diet supplemented with 10% elderberry juice powder without wheel access; and (4) high-fat diet supplemented with 10% elderberry juice powder with unlimited wheel access. Body weight gain, fat pads, and whole-body fat content in mice fed elderberry juice were significantly less than in mice fed the control diet independent of wheel access. At the end of the study, active mice fed elderberry juice ate significantly more than active mice fed a control diet. There was no difference in the physical activity between active groups. Elderberry juice increasedBifidobacterium, promotedAkkermansia and Anaeroplasma, and prevented the growth of Desulfovibrio. Elderberry juice is a potent inhibitor of diet-induced obesity with action mediated by the gut microbiota.

Anthocyanins: Potential phytochemical candidates for the amelioration of non-alcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is described by too much hepatic fat deposition causing steatosis, which further develops into nonalcoholic steatohepatitis (NASH), defined by necroinflammation and fibrosis, progressing further to hepatic cirrhosis, hepatocellular carcinoma, and liver failure. NAFLD is linked to different aspects of the metabolic syndrome like obesity, insulin resistance, hypertension, and dyslipidemia, and its pathogenesis involves several elements including diet, obesity, disruption of lipid homeostasis, and a high buildup of triglycerides and other lipids in liver cells. It is therefore linked to an increase in the susceptibility to developing diabetes mellitus and cardiovascular diseases. Several interventions exist regarding its management, but the availability of natural sources through diet will be a benefit in dealing with the disorder due to the immensely growing dependence of the population worldwide on natural sources owing to their ability to treat the root cause of the disease. Anthocyanins (ACNs) are naturally occurring polyphenolic pigments that exist in the form of glycosides, which are the glucosides of anthocyanidins and are produced from flavonoids via the phenyl propanoid pathway. To understand their mode of action in NAFLD and their therapeutic potential, the literature on in vitro, in vivo, and clinical trials on naturally occurring ACN-rich sources was exhaustively reviewed. It was concluded that ACNs show their potential in the treatment of NAFLD through their antioxidant properties and their efficacy to control lipid metabolism, glucose homeostasis, transcription factors, and inflammation. This led to the conclusion that ACNs possess efficacy in the amelioration of NAFLD and the various features associated with it. However, additional clinical trials are required to justify the potential of ACNs in NAFLD.

Effect of Blueberry Supplementation on a Diet-Induced Rat Model of Prediabetes-Focus on Hepatic Lipid Deposition, Endoplasmic Stress Response and Autophagy

Blueberries, red fruits enriched in polyphenols and fibers, are envisaged as a promising nutraceutical intervention in a plethora of metabolic diseases. Prediabetes, an intermediate state between normal glucose tolerance and type 2 diabetes, fuels the development of complications, including hepatic steatosis. In previous work, we have demonstrated that blueberry juice (BJ) supplementation benefits glycemic control and lipid profile, which was accompanied by an amelioration of hepatic mitochondrial bioenergetics. The purpose of this study is to clarify the impact of long-term BJ nutraceutical intervention on cellular mechanisms that govern hepatic lipid homeostasis, namely autophagy and endoplasmic reticulum (ER) stress, in a rat model of prediabetes. Two groups of male Wistar rats, 8-weeks old, were fed a prediabetes-inducing high-fat diet (HFD) and one group was fed a control diet (CD). From the timepoint where the prediabetic phenotype was achieved (week 16) until the end of the study (week 24), one of the HFD-fed groups was daily orally supplemented with 25 g/kg body weight (BW) of BJ (HFD + BJ). BW, caloric intake, glucose tolerance and insulin sensitivity were monitored throughout the study. The serum and hepatic lipid contents were quantified. Liver and interscapular brown and epidydimal white adipose tissue depots (iBAT and eWAT) were collected for histological analysis and to assess thermogenesis, ER stress and autophagy markers. The gut microbiota composition and the short-chain fatty acids (SCFAs) content were determined in colon fecal samples. BJ supplementation positively impacted glycemic control but was unable to prevent obesity and adiposity. BJ-treated animals presented a reduction in fecal SCFAs, increased markers of arrested iBAT thermogenesis and energy expenditure, together with an aggravation of HFD-induced lipotoxicity and hepatic steatosis, which were accompanied by the inhibition of autophagy and ER stress responses in the liver. In conclusion, despite the improvement of glucose tolerance, BJ supplementation promoted a major impact on lipid management mechanisms at liver and AT levels in prediabetic animals, which might affect disease course.

Synthetic Strategies of Thiazolidine-2,4-dione Derivatives for the Development of New Anti-diabetic Agents: Compressive Review

BACKGROUND

Thiazolidine-2,4-dione (2,4-TZD) is a flexible pharmacophore and a privileged platform and contains a five-membered ring with a 2-oxygen atom with double bond 2,4- position and one nitrogen atom as well as sulphur containing in the heterocyclic compound. A famous electron-rich nitrogen transporter combines invigorating electronic properties with the prospective for elemental applications. Thiazolidine-2,4-dione analogues have been synthesized using a variety of methods, all of which have shown to have a strong biological effect.

OBJECTIVES

The study of the biological activity of Thiazolidine-2,4-dione derivatives has been a fascinating field of pharmaceutical chemistry and has many purposes. This derivative described in the literature between 1995 to 2023 was the focus of this study. Thiazolidine-2,4-diones have been discussed in terms of their introduction, general method, synthetic scheme and antidiabetic significance in the current review.

CONCLUSION

Thiazolidine-2,4-diones are well-known heterocyclic compounds. The synthesis of Thiazolidine-2,4-diones has been described using a variety of methods. Antidiabetic activity has been discovered in several Thiazolidine-2,4-dione derivatives, which enhance further research. The use of Thiazolidine-2,4-diones to treat antidiabetics has piqued researchers' interest in learning more about thiazolidine-2,4-diones.

Anthocyanins' effects on diabetes mellitus and islet transplantation

The incidence of diabetes mellitus is dramatically increasing every year, causing a huge global burden. Moreover, existing anti-diabetic drugs inevitably bring adverse reactions, and the application of islet transplantation is often limited by the damage caused by oxidative stress after transplantation. Thus, new approaches are needed to combat the growing burden of diabetes mellitus. Anthocyanins are of great nutritional interest and have been documented that have beneficial effects on chronic diseases, including diabetes mellitus. Here, we describe the health effects of anthocyanins on diabetes mellitus and islet transplantation. Epidemiological studies demonstrated that moderate intake of anthocyanins leading to a reduction in risk of diabetes mellitus. Numerous experiments both animal and clinical studies also showed positive effects of anthocyanins on prevention and treatment of diabetes and diabetic complications. These effects of anthocyanins may be related to mechanisms of improving glucose and lipid metabolism and insulin resistance, antioxidant, and anti-inflammatory activities. In addition, damage and function of pancreatic islets after transplantation are also improved by anthocyanins. These findings suggest that daily intake of anthocyanins may not only improve nutritional metabolism in healthy individuals to prevent from diabetes, but also as a supplementary treatment of diabetes mellitus and islet transplantation. Thus, more evidence is needed to better understand the potential health benefits of anthocyanins.

Identification of Potential Mechanisms of Rk1 Combination with Rg5 in the Treatment of Type II Diabetes Mellitus by Integrating Network Pharmacology and Experimental Validation

In this study, we aimed to explore the potential targets and functional mechanisms of Rk1 combined with Rg5 (Rk1+Rg5) against type II diabetes mellitus (T2DM). Network pharmacology and molecular docking were used to predict and verify the targets and signaling pathways of Rk1+Rg5 against T2DM. The results were further confirmed by a db/db mouse model and a model using PA-induced L6 cells. According to network pharmacology, a total of 250 core targets of Rk1+Rg5 towards T2DM were identified; the insulin resistance signaling pathways were enriched by KEGG. Results of molecular docking indicated good binding affinity of Rk1 and Rg5 to Akt1. In vivo and in vitro studies further showed that Rk1+Rg5 is an inhibitor of skeletal muscle insulin resistance. The results showed that Rk1+Rg5 significantly improved the hyperglycemic state of db/db mice, alleviated dyslipidemia, and promoted skeletal muscle glucose uptake. This phenomenon was closely related to the alleviation of the insulin resistance in skeletal muscles. Finally, the combination activated the Akt signaling pathway and promoted GLUT4 translocation to the cell membrane for glucose uptake. Altogether, our findings, for the first time, demonstrate that the combination of Rk1 and Rg5 could be beneficial for anti-T2DM, possibly involving ameliorated insulin resistance.

Nutraceutical management of metabolic syndrome as a palliative and a therapeutic to coronavirus disease (COVID) crisis

The global market for medicinal plants and herbs is on the increase due to their desirability, efficacy, and less adverse effects as complementary and alternative medications to the orthodox pharmaceuticals, perhaps due to their natural components and qualities. Metabolic syndromes are managed with changes in diet, exercise, lifestyle modifications and the use of pharmacological agents. Plants are now known to have potent antioxidant and cholinergic activities which are relevant to the management of several metabolic syndromes, which are unfortunately, co-morbidity factors in the coronavirus disease crisis. This review will focus on the biological activities of some plant products used as complementary and alternative medicines in the management of metabolic syndromes, and on their reported antiviral, antithrombotic, angiotensin-converting enzyme inhibitory properties, which are integral to their usage in the management of viral infections and may give an avenue for prophylactic and therapeutics especially in the absence of vaccines/formulated antiviral therapies.

Food Polyphenols and Type II Diabetes Mellitus: Pharmacology and Mechanisms

Type II diabetes mellitus and its related complications are growing public health problems. Many natural products present in our diet, including polyphenols, can be used in treating and managing type II diabetes mellitus and different diseases, owing to their numerous biological properties. Anthocyanins, flavonols, stilbenes, curcuminoids, hesperidin, hesperetin, naringenin, and phenolic acids are common polyphenols found in blueberries, chokeberries, sea-buckthorn, mulberries, turmeric, citrus fruits, and cereals. These compounds exhibit antidiabetic effects through different pathways. Accordingly, this review presents an overview of the most recent developments in using food polyphenols for managing and treating type II diabetes mellitus, along with various mechanisms. In addition, the present work summarizes the literature about the anti-diabetic effect of food polyphenols and evaluates their potential as complementary or alternative medicines to treat type II diabetes mellitus. Results obtained from this survey show that anthocyanins, flavonols, stilbenes, curcuminoids, and phenolic acids can manage diabetes mellitus by protecting pancreatic β-cells against glucose toxicity, promoting β-cell proliferation, reducing β-cell apoptosis, and inhibiting α-glucosidases or α-amylase. In addition, these phenolic compounds exhibit antioxidant anti-inflammatory activities, modulate carbohydrate and lipid metabolism, optimize oxidative stress, reduce insulin resistance, and stimulate the pancreas to secrete insulin. They also activate insulin signaling and inhibit digestive enzymes, regulate intestinal microbiota, improve adipose tissue metabolism, inhibit glucose absorption, and inhibit the formation of advanced glycation end products. However, insufficient data are available on the effective mechanisms necessary to manage diabetes.

Analysis of Phenolic Acids and Flavonoids in Rabbiteye Blueberry Leaves by UPLC-MS/MS and Preparation of Nanoemulsions and Extracts for Improving Antiaging Effects in Mice

Rabbiteye blueberry leaves, a waste produced after harvest of blueberry, are rich in polyphenols. This study aims to analyze phenolic acids and flavonoids in blueberry leaves by UPLC-MS/MS and prepare nanoemulsions for determining anti-aging activity in mice. Overall, 30% ethanol was the most suitable extraction solvent for total phenolic acids and total flavonoids. A total of four phenolic acids and four flavonoids were separated within seven minutes for further identification and quantitation by UPLC-MS/MS in selective reaction monitoring (SRM) mode, with 3-O-caffeoylquinic acid being present in the highest amount (6474.2 μg/g), followed by quercetin-3-O-galactoside (1943.9 μg/g), quercetin-3-O-rutinoside (1036.6 μg/g), quercetin-3-O-glucoside (867.2 μg/g), 5-O-caffeoylquinic acid (815.8 μg/g), kaempferol-3-O-glucoside (309.7 μg/g), 3,5-dicaffeoylquinic acid (195.3 μg/g), and 4,5-dicaffeoylquinic acid (60.8 μg/g). The blueberry nanoemulsion was prepared by using an appropriate ratio of soybean oil, Tween 80, glycerol, ethanol, and water at 1.2%, 8%, 2%, 2%, and 86.8%, respectively, and mixing with dried blueberry extract, with the mean particle size and zeta potential being 16 nm and -54 mV, respectively. A high stability was observed during storage of nanoemulsion for 90 days at 4 °C and heated at 100 °C for 2 h. An animal study revealed that this nanoemulsion could elevate dopamine content in mice brain as well as superoxide dismutase, glutathione peroxidase, and catalase activities in mice liver while reducing the contents of malondialdehyde and protein carbonyl in mice brains. Collectively, the high-dose nanoemulsion possessed the highest efficiency in improving mice aging with a promising potential for development into a health food.

One-Week Elderberry Juice Treatment Increases Carbohydrate Oxidation after a Meal Tolerance Test and Is Well Tolerated in Adults: A Randomized Controlled Pilot Study

Obesity in the United States continues to worsen. Anthocyanin-rich fruits and vegetables provide a pragmatic dietary approach to slow its metabolic complications. Given American diet patterns, foods with high anthocyanin content could address dose-response challenges. The study objective was to determine the effect of 100% elderberry juice on measures of indirect calorimetry (IC) and insulin sensitivity/glucose tolerance in a placebo-controlled, randomized, crossover pilot study. Overweight and obese adults were randomized to a 5-week study which included 2 1-week periods of twice-daily elderberry juice (EBJ) or sugar-matched placebo consumption separated by a 3-week washout period. Following each 1-week test period, IC and insulin sensitivity/glucose tolerance was measured with a 3 h meal tolerance test (MTT). Treatment differences were tested with linear mixed modeling. A total of 22 prospective study volunteers (18 F/4 M) attended recruitment meetings, and 9 were analyzed for treatment differences. EBJ was well tolerated and compliance was 99.6%. A total of 6 IC measures (intervals) were created, which coincided with 10-20 min gaseous samplings in-between MTT blood samplings. Average CHO oxidation was significantly higher during the MTT after 1-week EBJ consumption (3.38 vs. 2.88 g per interval, EBJ vs. placebo, p = 0.0113). Conversely, average fat oxidation was significantly higher during the MTT after 1-week placebo consumption (1.17 vs. 1.47 g per interval, EBJ vs. placebo, p = 0.0189). This was in-line with a significantly lower average respiratory quotient after placebo treatment (0.87 vs. 0.84, EBJ vs. placebo, p = 0.0114). Energy expenditure was not different. There was no difference in serum glucose or insulin response between treatments. This pilot study of free-living volunteers describes significant change in IC but not insulin sensitivity with an EBJ intervention. Controlled feeding and increased sample size will help determine the utility of EBJ on these outcomes.

Vaccinium as Potential Therapy for Diabetes and Microvascular Complications

Diabetes mellitus is one of the most critical global health concerns, with a fast-growing prevalence. The incidence of diabetic vascular complications is also rapidly increasing, exacerbating the burden on individuals with diabetes and the consumption of public medical resources. Despite the overall improvements in the prevention, diagnosis, and treatment of diabetic microvascular complications in recent years, safe and effective alternative or adjunctive therapies are urgently needed. The mechanisms underlying diabetic vascular complications are complex, with hyperglycemia-induced oxidative stress and inflammation being the leading causes. Therefore, glycemic control, antioxidation, and anti-inflammation are considered the main targets for the treatment of diabetes and its vascular comorbidities. Vaccinium L. (Ericaceae) is a genus of plants enriched with polyphenolic compounds in their leaves and fruits. Vaccinium and its extracts have demonstrated good bioactivity in reducing blood glucose, oxidative stress, and inflammation, making them excellent candidates for the management of diabetes and diabetic vascular complications. Here, we review recent preclinical and clinical studies on the potential effect of Vaccinium on ameliorating diabetes and diabetic complications, particularly diabetic kidney disease and diabetic retinopathy.

The Role of Gut Microbiota in High-Fat-Diet-Induced Diabetes: Lessons from Animal Models and Humans

The number of diabetes mellitus patients is increasing rapidly worldwide. Diet and nutrition are strongly believed to play a significant role in the development of diabetes mellitus. However, the specific dietary factors and detailed mechanisms of its development have not been clearly elucidated. Increasing evidence indicates the intestinal microbiota is becoming abundantly apparent in the progression and prevention of insulin resistance in diabetes. Differences in gut microbiota composition, particularly butyrate-producing bacteria, have been observed in preclinical animal models as well as human patients compared to healthy controls. Gut microbiota dysbiosis may disrupt intestinal barrier functions and alter host metabolic pathways, directly or indirectly relating to insulin resistance. In this article, we focus on dietary fat, diabetes, and gut microbiome characterization. The promising probiotic and prebiotic approaches to diabetes, by favorably modifying the composition of the gut microbial community, warrant further investigation through well-designed human clinical studies.

Anthocyanins as Promising Molecules Affecting Energy Homeostasis, Inflammation, and Gut Microbiota in Type 2 Diabetes with Special Reference to Impact of Acylation

Anthocyanins, the red-orange to blue-violet colorants present in fruits, vegetables, and tubers, have antidiabetic properties expressed via modulating energy metabolism, inflammation, and gut microbiota. Acylation of the glycosyl moieties of anthocyanins alters the physicochemical properties of anthocyanins and improves their stability. Thus, acylated anthocyanins with probiotic-like property and lower bioavailability are likely to have different biological effects from nonacylated anthocyanins on diabetes. This work highlights recent findings on the antidiabetic effects of acylated anthocyanins from the perspectives of energy metabolism, inflammation, and gut microbiota compared to the nonacylated anthocyanins and particularly emphasizes the cellular and molecular mechanisms associated with the beneficial effects of these bioactive molecules, providing a new perspective to explore the different biological effects induced by structurally different anthocyanins. Acylated anthocyanins may have greater modulating effects on energy metabolism, inflammation, and gut microbiota in type 2 diabetes compared to nonacylated anthocyanins.

Blueberry Consumption and Changes in Obesity and Diabetes Mellitus Outcomes: A Systematic Review

Low-grade inflammation and oxidative stress are key mechanisms involved in obesity and related disorders. Polyphenols from blueberry (BB) and bilberries (BiB) might protect against oxidative damage and inflammation. To summarize the effects of BiB or BB consumption in parameters related to obesity and its comorbidities, a search of the literature was performed in PubMed, Embase, and Cochrane Library repositories to identify all studies that evaluated associations of whole BB or BiB with obesity and associated disorders. Thirty-one studies were eligible for inclusion in this review: eight clinical trials and 23 animal studies. In humans, BB consumption only consistently decreased oxidative stress and improved endothelial function. In rodents, BB or BiB consumption caused positive effects on glucose tolerance, nuclear factor-kappa B (Nf-κb) activity, oxidative stress, and triglyceride (TG) content in the liver and hepatic steatosis. The high content of anthocyanins present in BB and BiB seems to attenuate oxidative stress. The decrease in oxidative stress may have a positive impact on glucose tolerance and endothelial function. Moreover, in rodents, these berries seem to protect against hepatic steatosis, through the decreased accumulation of hepatic TGs. BB and BiB might also attenuate inflammation by decreasing Nf-κb activity and immune cell recruitment into the adipose tissue.

The effect of dietary supplementation with blueberry, cyanidin-3-O-β-glucoside, yoghurt and its peptides on gene expression associated with glucose metabolism in skeletal muscle obtained from a high-fat-high-carbohydrate diet induced obesity model

Obesity is a leading global health problem contributing to various chronic diseases, including type II diabetes mellitus (T2DM). The aim of this study was to investigate whether blueberries, yoghurt, and their respective bioactive components, Cyanidin-3-O-β-glucoside (C3G) and peptides alone or in combinations, alter the expression of genes related to glucose metabolism in skeletal muscles from diet-induced obese mice. In extensor digitorum longus (EDL), yoghurt up-regulated the expression of activation of 5’adenosine monophosphate-activated protein kinase (AMPK), insulin receptor substrate-1 (IRS-1), phosphatidylinositol-3 kinase (PI3K) and glucose transporter 4 (GLUT4), and down-regulated the expression of angiotensin II receptor type 1 (AGTR-1). The combination of blueberries and yoghurt down-regulated the mRNA expression of AGTR-1 and Forkhead box protein O1 (FoxO1) in the EDL. Whereas the combination of C3G and peptides down-regulated AGTR-1 and up-regulated GLUT4 mRNA expression in the EDL. In the soleus, blueberries and yoghurt alone, and their combination down-regulated AGTR-1 and up-regulated GLUT4 mRNA expression. In summary blueberries and yoghurt, regulated multiple genes associated with glucose metabolism in skeletal muscles, and therefore may play a role in the management and prevention of T2DM.

Recent advances in nuclear receptors-mediated health benefits of blueberry

BACKGROUND

Blueberry is rich in bioactive substances and has anti-oxidant, anti-inflammatory, anti-obesity, anti-cancer, neuroprotective, and other activities. Blueberry has been shown to treat diseases by mediating the transcription of nuclear receptors. However, evidence for nuclear receptor-mediated health benefits of blueberry has not been systematically reviewed.

PURPOSE

This review aims to summarize the nuclear receptor-mediated health benefits of blueberry.

METHODS

This study reviews all relevant literature published in NCBI PubMed, Scopus, Web of Science, and Google Scholar by January 2022. The relevant literature was extracted from the databases with the following keyword combinations: "biological activities" OR "nuclear receptors" OR "phytochemicals" AND "blueberry" OR "Vaccinium corymbosum" as well as free-text words.

RESULTS

In vivo and in vitro experimental results and clinical evidence have demonstrated that blueberry has health-promoting effects. Supplementing blueberry is beneficial to the treatment of cancer, the alleviation of metabolic syndrome, and liver protection. Blueberry can regulate the transcription of PPARs, ERs, AR, GR, MR, LXRs, and FXR and mediate the expressions of Akt, CYP 1Al, p53, and Bcl-2.

CONCLUSION

Blueberry can be targeted to treat various diseases by mediating the transcription of nuclear receptors. Nevertheless, further human research is needed.

Chronic Consumption of Cranberries (Vaccinium macrocarpon) for 12 Weeks Improves Episodic Memory and Regional Brain Perfusion in Healthy Older Adults: A Randomised, Placebo-Controlled, Parallel-Groups Feasibility Study

Background

Ageing is highly associated with cognitive decline and modifiable risk factors such as diet are believed to protect against this process. Specific dietary components and in particular, (poly)phenol-rich fruits such as berries have been increasingly recognised for their protection against age-related neurodegeneration. However, the impact of cranberries on cognitive function and neural functioning in older adults remains unclear.

Design

A 12-week parallel randomised placebo-controlled trial of freeze-dried cranberry powder was conducted in 60 older adults aged between 50 and 80 years. Cognitive assessment, including memory and executive function, neuroimaging and blood sample collection were conducted before and after the intervention to assess the impact of daily cranberry consumption on cognition, brain function and biomarkers of neuronal signalling.

Results

Cranberry supplementation for 12 weeks was associated with improvements in visual episodic memory in aged participants when compared to placebo. Mechanisms of action may include increased regional perfusion in the right entorhinal cortex, the accumbens area and the caudate in the cranberry group. Significant decrease in low-density lipoprotein (LDL) cholesterol during the course of the intervention was also observed. No significant differences were, however, detected for BDNF levels between groups.

Conclusions

The results of this study indicate that daily cranberry supplementation (equivalent to 1 small cup of cranberries) over a 12-week period improves episodic memory performance and neural functioning, providing a basis for future investigations to determine efficacy in the context of neurological disease. This trial was registered at clinicaltrials.gov as NCT03679533 and at ISRCTN as ISRCTN76069316.

Blueberry Supplementation in Midlife for Dementia Risk Reduction

Late-life dementia typically develops over a period of many years beginning in midlife. Prevalence of metabolic disturbance also accelerates in middle age and is a prominent risk factor for dementia. Preliminary studies indicate that blueberry supplementation can improve cognitive performance and influence metabolism and brain function and therefore may have a role in early intervention to prevent neurodegeneration. In a randomized controlled trial, we investigated the effects of daily blueberry supplementation in a middle-aged sample of insulin-resistant participants with elevated risk for future dementia. We enrolled overweight men and women, aged 50 to 65 years, with subjective cognitive decline (SCD) and performed pre- and post-intervention assessments of cognition and metabolism and exploratory measures of peripheral mitochondrial function. We observed improved performances for the blueberry group on measures of lexical access, p = 0.003, and memory interference, p = 0.04, and blueberry-treated participants reported reduced memory encoding difficulty in daily life activities, p = 0.03. The blueberry-treated group also exhibited correction of peripheral hyperinsulinemia, p = 0.04, and a modest trend for increased mitochondrial uncoupling, p = 0.11. The cognitive findings indicated improved executive ability in this middle-aged sample. In addition, the changes in metabolic and bioenergetic measures imply potential mechanistic factors associated with anthocyanin and proanthocyanidin actions. The demonstration of these benefits in middle-aged individuals with insulin resistance and SCD suggests that ongoing blueberry supplementation may contribute to protection against cognitive decline when implemented early in at-risk individuals.

Hypoglycemic bioactivity of anthocyanins: A review on proposed targets and potential signaling pathways

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease with complicated interrelationships responsible for initiating its pathogenesis. Novel strategies for the treatment of this devastating disease have attracted increasing attention worldwide. Anthocyanins are bioactive compounds that are widely distributed in the plant kingdom, and multiple studies have elucidated their beneficial role in preventing and managing T2DM. This review summarizes and comments on the hypoglycemic actions of anthocyanins from the perspective of molecular mechanisms and different target-related signaling pathways in vitro, in vivo, and clinical trials. Anthocyanins can ameliorate T2DM by functioning as carbohydrate digestive enzyme inhibitors, facilitating glucose transporter 4 (GLUT4) translocation, suppressing the effectiveness of dipeptidyl peptidase IV (DPP-IV), promoting glucagon-like peptide-1 (GLP-1) secretion, inhibiting protein tyrosine phosphatase 1B (PTP1B) overexpression, and interacting with sodium-glucose co-transporter (SGLT) to delay glucose absorption in various organs and tissues. In summary, anthocyanin is a promising and practical small molecule that can hyperglycemic symptoms and accompanying complications suffered by patients with diabetes. However, rational and potent doses for daily intake and clinical studies are required in the future.

The Multifunctional Role of Herbal Products in the Management of Diabetes and Obesity: A Comprehensive Review

Obesity and diabetes are the most demanding health problems today, and their prevalence, as well as comorbidities, is on the rise all over the world. As time goes on, both are becoming big issues that have a big impact on people’s lives. Diabetes is a metabolic and endocrine illness set apart by hyperglycemia and glucose narrow-mindedness because of insulin opposition. Heftiness is a typical, complex, and developing overall wellbeing worry that has for quite some time been connected to significant medical issues in individuals, all things considered. Because of the wide variety and low adverse effects, herbal products are an important hotspot for drug development. Synthetic compounds are not structurally diverse and lack drug-likeness properties. Thus, it is basic to keep on exploring herbal products as possible wellsprings of novel drugs. We conducted this review of the literature by searching Scopus, Science Direct, Elsevier, PubMed, and Web of Science databases. From 1990 until October 2021, research reports, review articles, and original research articles in English are presented. It provides top to bottom data and an examination of plant-inferred compounds that might be utilized against heftiness or potentially hostile to diabetes treatments. Our expanded comprehension of the systems of activity of phytogenic compounds, as an extra examination, could prompt the advancement of remedial methodologies for metabolic diseases. In clinical trials, a huge number of these food kinds or restorative plants, as well as their bioactive compounds, have been shown to be beneficial in the treatment of obesity.

Beneficial effects of blueberry supplementation on the components of metabolic syndrome: a systematic review and meta-analysis

Metabolic syndrome (MetS) is a combination of interconnected disorders that puts a heavy burden on societies. This study investigated the impact of blueberry (BB) supplementation on components of MetS. A...

Blueberry Counteracts Prediabetes in a Hypercaloric Diet-Induced Rat Model and Rescues Hepatic Mitochondrial Bioenergetics

The paramount importance of a healthy diet in the prevention of type 2 diabetes is now well recognized. Blueberries (BBs) have been described as attractive functional fruits for this purpose. This study aimed to elucidate the cellular and molecular mechanisms pertaining to the protective impact of blueberry juice (BJ) on prediabetes. Using a hypercaloric diet-induced prediabetic rat model, we evaluated the effects of BJ on glucose, insulin, and lipid profiles; gut microbiota composition; intestinal barrier integrity; and metabolic endotoxemia, as well as on hepatic metabolic surrogates, including several related to mitochondria bioenergetics. BJ supplementation for 14 weeks counteracted diet-evoked metabolic deregulation, improving glucose tolerance, insulin sensitivity, and hypertriglyceridemia, along with systemic and hepatic antioxidant properties, without a significant impact on the gut microbiota composition and related mechanisms. In addition, BJ treatment effectively alleviated hepatic steatosis and mitochondrial dysfunction observed in the prediabetic animals, as suggested by the amelioration of bioenergetics parameters and key targets of inflammation, insulin signaling, ketogenesis, and fatty acids oxidation. In conclusion, the beneficial metabolic impact of BJ in prediabetes may be mainly explained by the rescue of hepatic mitochondrial bioenergetics. These findings pave the way to support the use of BJ in prediabetes to prevent diabetes and its complications.

Anthocyanins Promote Learning through Modulation of Synaptic Plasticity Related Proteins in an Animal Model of Ageing

Anthocyanin-rich foods, such as berries, reportedly ameliorate age-related cognitive deficits in both animals and humans. Despite this, investigation into the mechanisms which underpin anthocyanin-mediated learning and memory benefits remains relatively limited. The present study investigates the effects of anthocyanin intake on a spatial working memory paradigm, assessed via the cross-maze apparatus, and relates behavioural test performance to underlying molecular mechanisms. Six-week supplementation with pure anthocyanins (2% w/w), administered throughout the learning phase of the task, improved both spatial and psychomotor performances in aged rats. Behavioural outputs were accompanied by changes in the expression profile of key proteins integral to synaptic function/maintenance, with upregulation of dystrophin, protein kinase B (PKB/Akt) and tyrosine hydroxylase, and downregulation of apoptotic proteins B-cell lymphoma-extra-large (Bcl-xL) and the phosphorylated rapidly accelerated fibrosarcoma (p-Raf). Separate immunoblot analysis supported these observations, indicating increased activation of extracellular signal-related kinase (ERK1), Akt Ser473, mammalian target of rapamycin (mTOR) Ser2448, activity-regulated cytoskeleton-associated protein (Arc/Arg 3.1) and brain-derived neurotrophic factor (BDNF) in response to anthocyanin treatment, whilst α-E-catenin, c-Jun N-terminal kinase (JNK1) and p38 protein levels decreased. Together, these findings suggest that purified anthocyanin consumption enhances spatial learning and motor coordination in aged animals and can be attributed to the modulation of key synaptic proteins, which support integrity and maintenance of synaptic function.

Probiotic-fermented blueberry juice prevents obesity and hyperglycemia in high fat diet-fed mice in association with modulating the gut microbiota

Blueberry dietary interventions have demonstrated remarkable potential against obesity and type 2 diabetes mellitus. However, the effects of fermented blueberry juice on metabolic syndrome, the gut microbiota, and insulin resistance have not yet been reported. This study aimed to investigate the potential of fermented blueberry juice against obesity, hyperglycemia, and gut microbiota dysbiosis in high fat diet (HFD)-fed mice. Our study findings revealed that supplementation with fresh blueberry juice (BBJ), and fermented blueberry juice with homemade probiotic starter (FBJ) or commercial starter (CFBJ) significantly decreased fat accumulation and low density lipoprotein cholesterol (LDL-C) levels in HFD-fed mice. FBJ showed relatively more potency to reduce body weight than BBJ and CFBJ. The percentage increase in the body weight of the FBJ group was almost the same as that in the normal chow diet (NCD) group, and was approximately 10% lower than the BBJ and CFBJ groups. Overall, all blueberry juices significantly ameliorated hyperlipidemia and insulin resistance in HFD-fed mice. Moreover, the dietary interventions with BBJ, FBJ, and CFBJ for 17 weeks significantly improved the community richness and diversity of the gut microflora along with an altered structure in the HFD-fed mice group. The FBJ treated mice group showed relatively low abundance of Firmicutes, obesity-related bacteria (Oscillibacter and Alistipes), and high abundance of lean bacteria (Akkermansia, Barnesiella, Olsenella, Bifidobacterium, and Lactobacillus) compared to the HFD-fed mice group. Furthermore, BBJ and FBJ treatments regulated the liver mRNA and protein expression levels involved in lipid and glucose metabolism. This study inferred that fermented blueberry juice could be used as a functional food to prevent the modern pandemics i.e., obesity and insulin resistance.

Review of Functional and Pharmacological Activities of Berries

Functional plant-based foods (such as fruits, vegetables, and berries) can improve health, have a preventive effect, and diminish the risk of different chronic diseases during in vivo and in vitro studies. Berries contain many phytochemicals, fibers, vitamins, and minerals. The primary phytochemicals in berry fruits are phenolic compounds including flavonoids (anthocyanins, flavonols, flavones, flavanols, flavanones, and isoflavonoids), tannins, and phenolic acids. Since berries have a high concentration of polyphenols, it is possible to use them for treating various diseases pharmacologically by acting on oxidative stress and inflammation, which are often the leading causes of diabetes, neurological, cardiovascular diseases, and cancer. This review examines commonly consumed berries: blackberries, blackcurrants, blueberries, cranberries, raspberries, black raspberries, and strawberries and their polyphenols as potential medicinal foods (due to the presence of pharmacologically active compounds) in the treatment of diabetes, cardiovascular problems, and other diseases. Moreover, much attention is paid to the bioavailability of active berry components. Hence, this comprehensive review shows that berries and their bioactive compounds possess medicinal properties and have therapeutic potential. Nevertheless, future clinical trials are required to study and improve the bioavailability of berries' phenolic compounds and extend the evidence that the active compounds of berries can be used as medicinal foods against various diseases.

Research progress on intervention effect and mechanism of protocatechuic acid on nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) has become a surge burden worldwide due to its high prevalence, with complicated deterioration symptoms such as liver fibrosis and cancer. No effective drugs are available for NALFD so far. The rapid growth of clinical demand has prompted the treatment of NAFLD to become a research hotspot. Protocatechuic acid (PCA) is a natural secondary metabolite commonly found in fruits, vegetables, grains, and herbal medicine. It is also the major internal metabolites of anthocyanins and other polyphenols. In the present manuscript, food sources, metabolic absorption, and efficacy of PCA were summarized while analyzing its role in improving NAFLD, as well as the mechanism involved. The results indicated that PCA could ameliorate NAFLD by regulating glucose and lipid metabolism, oxidative stress and inflammation, gut microbiota and metabolites. It was proposed for the first time that PCA might reduce NAFLD by enhancing the energy consumption of brown adipose tissue (BAT). However, the PCA administration mode and dose for NAFLD remain inconclusive. Fresh insights into the specific molecular mechanisms are required, while clinical trials are essential in the future. This review provides new targets and reasoning for the clinical application of PCA in the prevention and treatment of NAFLD.

Dietary anthocyanins as potential natural modulators for the prevention and treatment of non-alcoholic fatty liver disease: A comprehensive review

Nonalcoholic fatty liver disease (NAFLD) refers to a metabolic syndrome linked with type 2 diabetes mellitus, obesity, and cardiovascular diseases. It is characterized by the accumulation of triglycerides in the hepatocytes in the absence of alcohol consumption. The prevalence of NAFLD has abruptly increased worldwide, with no effective treatment yet available. Anthocyanins (ACNs) belong to the flavonoid subclass of polyphenols, are commonly present in various edible plants, and possess a broad array of health-promoting properties. ACNs have been shown to have strong potential to combat NAFLD. We critically assessed the literature regarding the pharmacological mechanisms and biopharmaceutical features of the action of ACNs on NAFLD in humans and animal models. We found that ACNs ameliorate NAFLD by improving lipid and glucose metabolism, increasing antioxidant and anti-inflammatory activities, and regulating gut microbiota dysbiosis. In conclusion, ACNs have potential to attenuate NAFLD. However, further mechanistic studies are required to confirm these beneficial impacts of ACNs on NAFLD.

Anthocyanin Bioactivity in Obesity and Diabetes: The Essential Role of Glucose Transporters in the Gut and Periphery

Obesity and type-2 diabetes trends continue to worsen in the United States. Dietary anthocyanins (typically provided by berries and other fruits) are reported to have protective effects against both conditions using a variety of experimental research models including animal and human feeding studies. This review highlights studies that explore the biochemical pathways in both tissue and rodent models which could explain clinical improvements noted with anthocyanin consumption. First, the primary mode of intestinal absorption of anthocyanins is through both sGLT1 and GLUT2 glucose transporters. Stronger binding affinities may allow anthocyanins to be more inhibitive to glucose absorption compared to the reverse, where GLUT2 expression may also be affected. Genetic or chemical inhibition of sGLT1 or GLUT2 demonstrate their essential function in anthocyanin absorption across the enterocyte, where the former interacts with a greater variety of anthocyanins but the latter is the major transporter for specific anthocyanin-glycosides. Once absorbed, anthocyanins positively modulate GLUT4 density and function in both skeletal muscle and adipose tissues via the upregulation of AMPK and restoration of insulin sensitivity. Antioxidant properties and phosphodiesterase inhibition by anthocyanins promote both mitochondrial function and density which could be novel targets for dietary management of obesity and its complications.

Blueberry Consumption Challenges Hepatic Mitochondrial Bioenergetics and Elicits Transcriptomics Reprogramming in Healthy Wistar Rats

An emergent trend of blueberries’ (BB) “prophylactic” consumption, due to their phytochemicals’ richness and well-known health-promoting claims, is widely scaled-up. However, the benefits arising from BB indiscriminate intake remains puzzling based on incongruent preclinical and human data. To provide a more in-depth elucidation and support towards a healthier and safer consumption, we conducted a translation-minded experimental study in healthy Wistar rats that consumed BB in a juice form (25 g/kg body weight (BW)/day; 14 weeks’ protocol). Particular attention was paid to the physiological adaptations succeeding in the gut and liver tissues regarding the acknowledged BB-induced metabolic benefits. Systemically, BB boosted serum antioxidant activity and repressed the circulating levels of 3-hydroxybutyrate (3-HB) ketone bodies and 3-HB/acetoacetate ratio. Moreover, BB elicited increased fecal succinic acid levels without major changes on gut microbiota (GM) composition and gut ultra-structural organization. Remarkably, an accentuated hepatic mitochondrial bioenergetic challenge, ensuing metabolic transcriptomic reprogramming along with a concerted anti-inflammatory pre-conditioning, was clearly detected upon long-term consumption of BB phytochemicals. Altogether, the results disclosed herein portray a quiescent mitochondrial-related metabolomics and hint for a unified adaptive response to this nutritional challenge. The beneficial or noxious consequences arising from this dietary trend should be carefully interpreted and necessarily claims future research.

The Therapeutic Potential of Anthocyanins: Current Approaches Based on Their Molecular Mechanism of Action

Anthocyanins are natural phenolic pigments with biological activity. They are well-known to have potent antioxidant and antiinflammatory activity, which explains the various biological effects reported for these substances suggesting their antidiabetic and anticancer activities, and their role in cardiovascular and neuroprotective prevention. This review aims to comprehensively analyze different studies performed on this class of compounds, their bioavailability and their therapeutic potential. An in-depth look in preclinical, in vitro and in vivo, and clinical studies indicates the preventive effects of anthocyanins on cardioprotection, neuroprotection, antiobesity as well as their antidiabetes and anticancer effects.

Select Polyphenol-Rich Berry Consumption to Defer or Deter Diabetes and Diabetes-Related Complications

Berries are considered "promising functional fruits" due to their distinct and ubiquitous therapeutic contents of anthocyanins, proanthocyanidins, phenolic acids, flavonoids, flavanols, alkaloids, polysaccharides, hydroxycinnamic, ellagic acid derivatives, and organic acids. These polyphenols are part of berries and the human diet, and evidence suggests that their intake is associated with a reduced risk or the reversal of metabolic pathophysiologies related to diabetes, obesity, oxidative stress, inflammation, and hypertension. This work reviewed and summarized both clinical and non-clinical findings that the consumption of berries, berry extracts, purified compounds, juices, jams, jellies, and other berry byproducts aided in the prevention and or otherwise management of type 2 diabetes mellitus (T2DM) and related complications. The integration of berries and berries-derived byproducts into high-carbohydrate (HCD) and high-fat (HFD) diets, also reversed/reduced the HCD/HFD-induced alterations in glucose metabolism-related pathways, and markers of oxidative stress, inflammation, and lipid oxidation in healthy/obese/diabetic subjects. The berry polyphenols also modulate the intestinal microflora ecology by opposing the diabetic and obesity rendered symbolic reduction of Bacteroidetes/Firmicutes ratio, intestinal mucosal barrier dysfunction-restoring bacteria, short-chain fatty acids, and organic acid producing microflora. All studies proposed a number of potential mechanisms of action of respective berry bioactive compounds, although further mechanistic and molecular studies are warranted. The metabolic profiling of each berry is also included to provide up-to-date information regarding the potential anti-oxidative/antidiabetic constituents of each berry.

The role of anthocyanins as antidiabetic agents: from molecular mechanisms to in vivo and human studies

Diabetes mellitus is a chronic metabolic disease characterized by high blood glucose concentration. Nowadays, type 2 diabetes or insulin resistant diabetes is the most common diabetes, mainly due to unhealthy lifestyle. Healthy habits like appropriate nutritional approaches or the consumption of certain natural products or food supplements have been suggested as non-pharmacological strategies for the treatment and prevention of type 2 diabetes. Some of the main bioactive compounds from plant foods are polyphenols, important mainly for their antioxidant capacity in oxidative stress conditions and ageing. Anthocyanins are polyphenols of the flavonoid group, which act as pigments in plants, especially in fruits such as berries. A search of in vitro, in vivo and human studies in relation with antidiabetic properties of anthocyanins has been performed in different electronic databases. Results of this review demonstrate that these compounds have the ability to inhibit different enzymes as well as to influence gene expression and metabolic pathways of glucose, such as AMPK, being able to modulate diabetes and other associated disorders, as hyperlipidaemia, overweight, obesity and cardiovascular diseases. Additionally, human interventional studies have shown that high doses of anthocyanins have potential in the prevention or treatment of type 2 diabetes; nevertheless, anthocyanins used in these studies should be standardized and quantified in order to make general conclusions about its use and to claim benefits for the human population.

The Influence of Supplementation of Anthocyanins on Obesity-Associated Comorbidities: A Concise Review

Anthocyanins are water-soluble plant pigments, and based on their chemical structure (nature, position, and the number of sugar moieties attached; the number of hydroxyl groups; acylation of sugars with acids) about 635 different anthocyanins have been identified and reported from plants. Cyanidin, peonidin, pelargonidin, petunidin, and malvidin are the commonly found anthocyanidins (aglycon forms of anthocyanins) in edible plants out of almost 25 anthocyanidins that are identified (based on the position of methoxyl and hydroxyl groups in the rings) in nature. Anthocyanins are known for numerous health benefits including anti-diabetes, anti-obesity, anti-inflammatory bowel disease, anti-cancer, etc. Obesity can be defined as excessive or abnormal adipose tissue and body mass, which increases the risk of developing chronic diseases such as diabetes, cardiovascular diseases, cancers, etc. The manuscript summarizes the recent updates in the effects of anthocyanins supplementation on the health status of obese subjects, and briefly the results of in vitro and in vivo studies. Several studies confirmed that the consumption of anthocyanins-rich food improved obesity-associated dysbiosis in gut microbiota and inflammation in adipose tissue. Anthocyanin consumption prevents obesity in healthy subjects, and aids in maintaining or reducing the body weight of obese subjects, also improving the metabolism and energy balance. Though preclinical studies proved the beneficial effects of anthocyanins such as the fact that daily intake of anthocyanin rich fruits and vegetables might aid weight maintenance in every healthy individual, Juҫara pulp might control the inflammatory status of obesity, Queen garnet plum juice reduced the blood pressure and risk factors associated with metabolic disorders, and highbush organic blueberries improved the metabolism of obese individuals, we don't have an established treatment procedure to prevent or manage the over-weight condition and its comorbidities. Thus, further studies on the optimum dose, duration, and mode of supplementation of anthocyanins are required to develop an anthocyanins-based clinical procedure.

Recent Research on the Health Benefits of Blueberries and Their Anthocyanins

Awareness of the human health benefits of blueberries is underpinned by a growing body of positive scientific evidence from human observational and clinical research, plus mechanistic research using animal and in vitro models. Blueberries contain a large number of phytochemicals, including abundant anthocyanin pigments. Of their various phytochemicals, anthocyanins probably make the greatest impact on blueberry health functionality. Epidemiological studies associate regular, moderate intake of blueberries and/or anthocyanins with reduced risk of cardiovascular disease, death, and type 2 diabetes, and with improved weight maintenance and neuroprotection. These findings are supported by biomarker-based evidence from human clinical studies. Among the more important healthful aspects of blueberries are their anti-inflammatory and antioxidant actions and their beneficial effects on vascular and glucoregulatory function. Blueberry phytochemicals may affect gastrointestinal microflora and contribute to host health. These aspects have implications in degenerative diseases and conditions as well as the aging process. More evidence, and particularly human clinical evidence, is needed to better understand the potential for anthocyanin-rich blueberries to benefit public health. However, it is widely agreed that the regular consumption of tasty, ripe blueberries can be unconditionally recommended.

Wild blueberry proanthocyanidins shape distinct gut microbiota profile and influence glucose homeostasis and intestinal phenotypes in high-fat high-sucrose fed mice

Blueberries are a rich source of polyphenols, widely studied for the prevention or attenuation of metabolic diseases. However, the health contribution and mechanisms of action of polyphenols depend on their type and structure. Here, we evaluated the effects of a wild blueberry polyphenolic extract (WBE) (Vaccinium angustifolium Aiton) on cardiometabolic parameters, gut microbiota composition and gut epithelium histology of high-fat high-sucrose (HFHS) diet-induced obese mice and determined which constitutive polyphenolic fractions (BPF) was responsible for the observed effects. To do so, the whole extract was separated in three fractions, F1) Anthocyanins and phenolic acids, F2) oligomeric proanthocyanidins (PACs), phenolic acids and flavonols (PACs degree of polymerization DP < 4), and F3) PACs polymers (PACs DP > 4) and supplied at their respective concentration in the whole extract. After 8 weeks, WBE reduced OGTT AUC by 18.3% compared to the HFHS treated rodents and the F3 fraction  contributed the most to this effect. The anthocyanin rich F1 fraction did not reproduce this response. WBE and the BPF restored the colonic mucus layer. Particularly, the polymeric PACs-rich F3 fraction increased the mucin-secreting goblet cells number. WBE caused a significant 2-fold higher proportion of Adlercreutzia equolifaciens whereas oligomeric PACs-rich F2 fraction increased by 2.5-fold the proportion of Akkermansia muciniphila. This study reveals the key role of WBE PACs in modulating the gut microbiota and restoring colonic epithelial mucus layer, providing a suitable ecological niche for mucosa-associated symbiotic bacteria, which may be crucial in triggering health effects of blueberry polyphenols.

Fruits

Fruits come in a wide variety of colors, shapes, and flavors. This chapter will cover selected fruits that are known to be healthy and highly nutritious. These fruits were chosen due to their common usage and availability. Since it is not possible to cover all health benefits or essential nutrients and important phytochemicals of the fruit composition, this chapter will focus on the key valuable constituents and their potential health effects.

Dietary plant flavonoids in prevention of obesity and diabetes

Obesity and diabetes are the most prevailing chronic metabolic diseases worldwide from mainly lipid and glucose metabolic dysfunctions and their incidence is increasing at an alarming high rate. Obesity is characterized by excess fat accumulation in WAT and liver and is the central player of insulin resistance in the peripheral tissues from chronic inflammation, lipotoxicity and gut dysbiosis, and plays a key role for development of type 2 diabetes (T2DM) and vascular diseases. Diabetes mellitus, known as diabetes, is chiefly characterized by hyperglycaemia from impaired insulin secretion and insulin resistance. Several identified mutant genes in insulin secretion and resistance and various environmental factors are considered responsible for the onset of this disease. Currently available oral synthetic drugs, biguanides, incretin mimetic, GLP-1R and PPAR agonists and DPP-4 inhibitors for management of obesity and diabetes have several adverse effects in patients on long-term use. Emerging evidence supports the efficacy of dietary plant flavonoids in prevention and attenuation of obesity and diabetes by the protection and proliferation of pancreatic beta-cells and improvement of their insulin secretory function via activation of cAMP/PKA signaling pathway as well as in the improvement of insulin sensitivity in the peripheral metabolic tisssues for glucose uptake and utilization via inhibition of inflammation, lipotoxicity and oxidative stress. These flavonoids improve GLUT-4 expression and translocation to plasma membrane by activation of insulin-sensitive PI3K/Akt signaling and insulin-independent AMPK, SIRT-1 and MOR activation pathways for regulation of glucose homeostasis, and improve fat oxidation and reduce lipid synthesis by regulation of related genes for lipid homeostasis in the body of obese diabetic animals. In this chapter, we have highlighted all these beneficial anti-obesity and antidiabetic potentials of some dietary plant flavonoids along with their molecular actions, bioavailability and pharmacokinetics. In addition, the present understanding and management of obesity and diabetes are also focused.

An Anthocyanin-Rich Mixed-Berry Intervention May Improve Insulin Sensitivity in a Randomized Trial of Overweight and Obese Adults

Evidence supports the beneficial effects of berries on glucoregulation, possibly related to flavonoid content, fiber content, or both. The purpose of this study was to assess the potential of mixed berries to improve insulin sensitivity and to identify the potential role of flavonoids and fiber. In a randomized cross-over trial with four treatment periods, overweight/obese men and women were fed a controlled 45% fat diet for one week prior to a meal-based glucose tolerance test. The same base diet was provided during each feeding period with the addition of one of four treatments: whole mixed berries, sugar matched mixed berry juice, sugar matched gelatin, and sugar/fiber matched gelatin. Subjects then completed a meal-based oral glucose tolerance test. Serum glucose, insulin and non-esterified fatty acids were not different between individual treatments. However, in a secondary analysis, the combined berry preparations resulted in a lower serum insulin area under the curve (difference of 0.15 ± 0.066 ln pmol min/mL, mean ± SE, p = 0.0228), compared to the combined gelatin treatments, while the difference for serum glucose did not quite meet statistical significance (difference of 0.17 ± 0.093 ln mg·min/dL, mean ± SE, p = 0.0738). These results suggest the potential for mixed berry preparations to improve post-prandial insulin response.

The effect of total anthocyanin-base standardized (Cornus mas L.) fruit extract on liver function, tumor necrosis factor α, malondealdehyde, and adiponectin in patients with non-alcoholic fatty liver: a study protocol for a double-blind randomized clinical trial

Background

Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases worldwide. Evidence showed that anthocyanins might have effects on NAFLD. Protective effects of Cornelian cherry (Cornus mas L.) extract, as an anthocyanins-rich source, on liver were reported in animal studies. However, very few clinical trials were conducted in this regard. Thus, the aim of this research will be to evaluate the effect of supplementation with total anthocyanin-base standardized cornelian cherry fruit extract on liver function (Serum levels of Alanine aminotransferase (ALT), Aspartate aminotransferase (AST), cytokeratin-18 fragment M30 (CK-18 M30), as well as steatosis and fibrosis of liver), tumor necrosis factor α (TNF-α), malondealdehyde (MDA), and adiponectin in patients with NAFLD.

Methods

In a double-blind randomized clinical trial, 80 NAFLD patients will be studied. The patients will be randomly assigned into two groups. The intervention group will receive the cornelian cherry extract, containing 320 mg.d^− 1 anthocyanins, per day for 12 weeks. The control group will also take the placebo daily for 12 weeks. Liver function (Serum levels of AST, ALT and CK-18 M30; steatosis and fibrosis of liver), serum levels of TNF-α, MDA, and adiponectin will be measured at the baseline and the end of trial for both groups and their results will be compared.

Discussion

Considering evidences about the useful impacts of anthocyanins on NAFLD, the effects of supplementation with cornelian cherry extract will be investigated on the important variables related to NAFLD.

Trial registration

Iranian Registry of Clinical Trials (IRCT20180419039359N1).

Whole blueberry protects pancreatic beta-cells in diet-induced obese mouse

Background

Blueberry is rich in bioactive substances and possesses powerful antioxidant potential, which can protect against oxidant-induced and inflammatory cell damage and cytotoxicity. The aim of this study was to determine how blueberry affects glucose metabolism and pancreatic β-cell proliferation in high fat diet (HFD)-induced obese mice.

Methods

Wild type male mice at age of 4 weeks received two different kinds of diets: high-fat diet (HFD) containing 60% fat or modified HFD supplemented with 4% (wt:wt) freeze-dried whole blueberry powder (HFD + B) for 14 weeks. A separate experiment was performed in mice fed with low-fat diet (LFD) containing 10% fat or modified LFD + B supplemented with 4% (wt:wt) freeze-dried whole blueberry powder. The metabolic parameters including blood glucose and insulin levels, glucose and insulin tolerances were measured.

Results

Blueberry-supplemented diet significantly increased insulin sensitivity and glucose tolerance in HFD + B mice compared to HFD mice. However, no difference was observed in blood glucose and insulin sensitivity between LFD + B and LFD mice. In addition, blueberry increased β-cell survival and prevented HFD-induced β-cell expansion. The most important finding was the observation of presence of small scattered islets in blueberry treated obese mice, which may reflect a potential role of blueberry in regenerating pancreatic β-cells.

Conclusions

Blueberry-supplemented diet can prevent obesity-induced insulin resistance by improving insulin sensitivity and protecting pancreatic β-cells. Blueberry supplementation has the potential to protect and improve health conditions for both type 1 and type 2 diabetes patients.

Electronic supplementary material

The online version of this article (10.1186/s12986-019-0363-6) contains supplementary material, which is available to authorized users.

Health promoting properties of blueberries: a review

With the strengthening of the link between diet and health, several foodstuffs have emerged as possessing potential health benefits such as phenolic rich fruits and vegetables. Blueberries, along with other berries, given their flavonoid and antioxidant content have long since been considered as a particularly interesting health promoting fruit. Therefore, the present work aimed to compile the existing evidences regarding the various potential benefits of blueberry and blueberry based products consumption, giving particular relevance to in vivo works and epidemiological studies whenever available. Overall, the results demonstrate that, while the evidences that support a beneficial role of blueberry and blueberry extracts consumption, further human based studies are still needed.