Pharmacokinetic profile of bilberry anthocyanins in rats and the role of glucose transporters: LC–MS/MS and computational studies

Stabilization effect and interaction mechanism of mannoprotein on anthocyanins in mulberry juice

This study aimed to investigate the problem of color instability in mulberry juice, examine the effect of mannoprotein (MP) dosage on improving the stability of anthocyanins in mulberry juice, and explore the molecular binding mechanism between them. As the mass ratio of anthocyanins to MP of 1.07 × 10-3: 1-1.65 × 10-3: 1, the retention rates of anthocyanins in mulberry juice and simulated system were significantly improved in the photostability experiment, with the highest increase of 128.89 % and 24.11 %, respectively. In the thermal stability experiment, it increased by 7.96 % and 18.49 %, respectively. The synergistic effect of combining MP with anthocyanins has been demonstrated to greatly enhance their antioxidant capacity, as measured by ABTS, FRAP, and potassium ferricyanide reduction method. Furthermore, MP stabilized more anthocyanins to reach the intestine in simulated in vitro digestion. MP and cyanidin-3-glucoside (C3G) interacted with each other through hydrogen bonding and hydrophobic interactions. Specific amino acid residues involved of MP in binding process were identified as threonine (THR), isoleucine (ILE) and arginine (ARG). The identification of the effective mass concentration ratio range and binding sites of MP and anthocyanins provided valuable insights for the application of MP in mulberry juice.

Co-encapsulation of curcumin and anthocyanins in bovine serum album-fucoidan nanocomplex with a two-step pH-driven method

BACKGROUND

Curcumin (CUR) and anthocyanins (ACN) are recommended due to their bioactivities. However, their nutritional values and health benefits are limited by their low oral bioavailability. The incorporation of bioactive substances into polysaccharide-protein composite nanoparticles is an effective way to enhance their bioavailability. Accordingly, this study explored the fabrication of bovine serum albumin (BSA)-fucoidan (FUC) hybrid nanoparticles using a two-step pH-driven method for the delivery of CUR and ACN.

RESULTS

Under a 1:1 weight ratio of BSA to FUC, the point of zero charge moved from pH ⁓ 4.7 for BSA to around 2.5 for FUC-coated BSA, and the formation of BSA-FUC nanocomplex was pH-dependent by showing the maximum CUR emission wavelength shifting from 546 nm (CUR-loaded BSA-FUC at pH 4.7) and 544 nm (CUR/ACN-loaded BSA-FUC nanoparticles at pH 4.7) to 540 nm (CUR-loaded BSA-FUC at pH 6.0) and 539 nm (CUR/ACN-loaded BSA-FUC nanoparticles at pH 6.0). Elevated concentrations of NaCl from 0 to 2.5 mol L-1 caused particle size increase from about 250 to about 800 nm, but showing no effect on the encapsulation efficiency of CUR. The CUR and ACN entrapped, respectively, in the inner and outer regions of the BSA-FUC nanocomplex were released at different rates. After incubation for 10 h, more than 80% of ACN was released, while less than 25% of CUR diffused into the receiving medium, which fitted well to Logistic and Weibull models.

CONCLUSION

In summary, the BSA-FUC nanocomposites produced by a two-step pH-driven method could be used for the co-delivery of hydrophilic and hydrophobic nutraceuticals. © 2023 Society of Chemical Industry.

The promising stability of carboxylpyranocyanidin-3-O-glucoside during food processing and simulated digestion and its bioavailability research

BACKGROUND

Pyranoanthocyanins are stable anthocyanin derivatives. Carboxylpyranoanthocyanin is one of the simplest pyranoanthocyanin, among which the production of carboxylpyranocyanidin-3-O-glucoside (crboxyl-pycy-3-gluc) is most feasible as a result of the abundance of its reactant, cyanidin-3-O-glucoside (Cy-3-gluc).

RESULTS

In the present study, carboxyl-pycy-3-gluc was synthesized and its stability during processing and after ingestion as well as its bioavailability in vivo were comprehensively evaluated. Our results indicated that the color of carboxyl-pycy-3-gluc remained more stable compared to Cy-3-gluc when facing the large-span pH variation. The high retention of anthocyanin symbolized the superb stability under thermal processing, sulfur dioxide bleaching and ultrasonic treatment of carboxyl-pycy-3-gluc. Because of the stability under the alkaline condition, carboxyl-pycy-3-gluc is more stable after oral-gastrointestinal digestion. After in vitro gut microbiota fermentation, the retention of carboxyl-pycy-3-gluc was significantly higher than that of Cy-3-gluc. The larger molecular size made absorption of carboxyl-pycy-3-gluc into blood more difficult than its precursor.

CONCLUSION

The present study demonstrated the promising stability of carboxyl-pycy-3-gluc during food processing and after digestion, confirming the potential of carboxyl-pycy-3-gluc as a colorant. © 2023 Society of Chemical Industry.

Lowering glycemic levels via gastrointestinal tract factors: the roles of dietary fiber, polyphenols, and their combination

Dietary fiber (DF) and polyphenols (DP) are typical blood sugar-lowering components, and both play distinct yet interconnected roles in exerting their blood sugar-lowering effects. We comprehensively summarized the single and combined effects of DF and DP on blood glucose homeostasis through regulating the relevant factors in the upper gastrointestinal tract (UGT) and lower gastrointestinal tract (LGT). In the UGT, DF slowed down glucose metabolism by enhancing digesta viscosity and hindering enzyme-substrate interaction. DP primarily targeted enzymes and substrates. When combined, DP enhanced the adsorption capacity of DF for glucose. DF weakened DP's inhibitory effect on enzymes. Both DF and DP disrupted glucose intestinal uptake via physical or genomic modulation, but the co-consumption of DF and DP demonstrated a lower inhibitory effect on glucose uptake than DP alone. In the LGT, DF and DP showed synergistic or antagonistic effects on gut microbiota. Remarkably, whole foods exhibited potent prebiotic effects due to their compound-rich matrix, potentially enhancing glucose homeostasis and expanding dietary options for glucose regulation research.

Advances in the Preparation, Stability, Metabolism, and Physiological Roles of Anthocyanins: A Review

Anthocyanins are natural flavonoid polyphenolic compounds widely found in fruits and vegetables. They exhibit antioxidant properties and prophylactic effects in the immune and cardiovascular systems, confer protection against cancer, and contribute to the prevention of cardiovascular diseases. Thus, their incorporation into functional foods, pharmaceuticals, supplements, and cosmetic formulations aims at promoting human well-being. This review comprehensively outlined the structural attributes of anthocyanins, expanding upon diverse methodologies employed for their extraction and production. Additionally, the stability, metabolic pathways, and manifold physiological functions of anthocyanins were discussed. However, their constrained fat solubility, susceptibility to instability, and restricted bioavailability collectively curtail their applicability and therapeutic efficacy. Consequently, a multidimensional approach was imperative, necessitating the exploration of innovative pathways to surmount these limitations, thereby amplifying the utilitarian significance of anthocyanins and furnishing pivotal support for their continual advancement and broader application.

Anthocyanins as Immunomodulatory Dietary Supplements: A Nutraceutical Perspective and Micro-/Nano-Strategies for Enhanced Bioavailability

Anthocyanins (ACNs) have attracted considerable attention for their potential to modulate the immune system. Research has revealed their antioxidant and anti-inflammatory properties, which play a crucial role in immune regulation by influencing key immune cells, such as lymphocytes, macrophages, and dendritic cells. Moreover, ACNs contribute towards maintaining a balance between proinflammatory and anti-inflammatory cytokines, thus promoting immune health. Beyond their direct effects on immune cells, ACNs significantly impact gut health and the microbiota, essential factors in immune regulation. Emerging evidence suggests that they positively influence the composition of the gut microbiome, enhancing their immunomodulatory effects. Furthermore, these compounds synergize with other bioactive substances, such as vitamins and minerals, further enhancing their potential as immune-supporting dietary supplements. However, detailed clinical studies must fully validate these findings and determine safe dosages across varied populations. Incorporating these natural compounds into functional foods or supplements could revolutionize the management of immune-related conditions. Personalized nutrition and healthcare strategies may be developed to enhance overall well-being and immune resilience by fully understanding the mechanisms underlying the actions of their components. Recent advancements in delivery methods have focused on improving the bioavailability and effectiveness of ACNs, providing promising avenues for future applications.

Pre-Protection and Mechanism of Crude Extracts from Dioscorea alata L. on H2O2-Induced IPEC-J2 Cells Oxidative Damage

The purple tubers of Dioscorea alata L. have been found to contain a variety of bioactive chemical components, including anthocyanins, which make it significant to investigate the pre-protective effects of Dioscorea alata L. and its crude extracts on cells prior to oxidative stress. To establish a suitable oxidative damage model, an injured model of IPEC-J2 cells was created using H₂O₂ as the oxidant. Specifically, when the concentration of H₂O₂ was 120 μmol/L and the injured time was 8 h, the survival rate of cells decreased to approximately 70%, and the cells exhibited a noticeable oxidative stress reaction. Moreover, the crude extracts of Dioscorea alata L. demonstrated beneficial pre-protective effects on IPEC-J2 cells by increasing the total antioxidant capacity (T-AOC) and catalase (CAT) activities, augmenting the expression of total superoxide dismutase (T-SOD) and its genes, reducing the content of malondialdehyde (MDA) and the activity of glutathione peroxidase (GSH-P_X) and its expression of genes, and promoting the expression of glucose transporter SGLT1 gene while reducing that of GULT2 gene, thereby facilitating the entry of anthocyanins into cells. In addition, the 50 μg/mL crude extracts effectively inhibited the phosphorylation of IκB and the p65 protein, thus reducing cellular oxidative stress. Given these findings, Dioscorea alata L. can be considered a natural antioxidant for practical breeding and production purposes, with an optimal concentration of crude extracts in this experiment being 50 μg/mL.

Distribution, Antioxidant Capacity, Bioavailability and Biological Properties of Anthocyanin Pigments in Blood Oranges and Other Citrus Species

Anthocyanins are natural pigments that give a red, purple, and blue color to many plant, flower, fruit, and vegetable species. Their presence within the genus Citrus was first reported in 1916, and it is well-known that the red color of the flesh and rind of blood (red or pigmented) oranges (Citrus sinensis L. Osbeck) is due to the presence of anthocyanins. They are also present in the young shoots, flowers, and peel of lemon (Citrus limon (L.) Burm. f.), citron (Citrus medica L.), and other citrus species. Since then, the scientific community has expressed increasing interest in studying their profile and distribution, with many published studies focused on the quali-quantitative pattern in the different vegetative tissues belonging to the genus Citrus. Moreover, with the discovery of their relevant antioxidant activity, owing to their ability to capture free radicals, much research has been performed in the last two decades on their radical scavenging power, in vitro and in vivo biological properties, and anticarcinogenic capacity, also focusing attention on their bioavailability for humans. The present work is intended as a comprehensive review of the advances in scientific research on anthocyanin pigments naturally occurring within the genus Citrus, including their natural distribution, antioxidant capacity, bioavailability, and biological value and properties. The scientific evidence herein reported can be used to further increase the knowledge of this class of compounds and represents a valuable and comprehensive contribution to promoting anthocyanin-rich citrus fruit consumption as a healthy dietary habit.

The Effect of Ferulic Acid-Grafted Chitosan (FA-g-CS) on the Transmembrane Transport of Anthocyanins by sGLT1 and GLUT2

This work aims to evaluate the effect of ferulic acid-grafted chitosan (FA-g-CS) on the interaction between anthocyanin (ANC) and sGLT1/GLUT2 and their functions in ANC transmembrane transport using Caco-2 cells. The transmembrane transport experiments of ANC showed its low transport efficiency (Papp < 10⁻⁶ cm/s), whereas the phenomenon of a significantly rise in anthocyanins transport efficiency was observed with the incubation of FA-g-CS (p < 0.05). In order to investigate the mechanism of FA-g-CS improving ANC transmembrane transport, Caco-2 cells were transfected with small interfering RNA (siRNA) specific for transporters sGLT1 and GLUT2, and incubated with ANC, FA-g-CS, or their combination. Subsequently, Western blot analyses and immunofluorescence staining were carried out to monitor the intracellular sGLT1 and GLUT2 levels. These siRNA-transfected cells, incubated with compounds, indicate that sGLT1 and GLUT2 participated in the ANC transmembrane transport and that FA-g-CS, ANC, or their combination enhance sGLT1/GLUT2 expression. In particular, Caco-2 cells incubated with both FA-g-CS and ANC show significantly increased sGLT1 or GLUT2 expression (>80%) compared with exclusively using FA-g-CS or ANC (<60%). Molecular docking results demonstrate that there is a good binding between FA-g-CS/ANC and sGLT1 or GLUT2. These results highlight that FA-g-CS promotes the transmembrane transport of ANC by influencing the interaction between ANC and sGLT1/GLUT2; the interaction between FA-g-CS and ANC could be another key factor that improves the bioavailability of ANC.

Nanoencapsulated anthocyanin as a functional ingredient: Technological application and future perspectives

Anthocyanins are an important group of phenolic compounds responsible for pigmentation in several plants, and regular consumption is associated with a reduced risk of several diseases. However, the application of anthocyanins in foods represents a challenge due to molecular instability. The encapsulation of anthocyanins in nanostructures is a viable way to protect from the factors responsible for degradation and enable the industrial application of these compounds. Nanoencapsulation is a set of techniques in which the bioactive molecules are covered by resistant biomaterials that protect them from chemical and biological factors during processing and storage. This review comprehensively summarizes the existing knowledge about the structure of anthocyanins and molecular stability, with a critical analysis of anthocyanins' nanoencapsulation, the main encapsulating materials (polysaccharides, proteins, and lipids), and techniques used in the formation of nanocarriers to protect anthocyanins. Some studies point to the effectiveness of nanostructures in maintaining anthocyanin stability and antioxidant activity. The main advantages of the application of nanoencapsulated anthocyanins in foods are the increase in the nutritional value of the food, the addition of color, the increase in food storage, and the possible increase in bioavailability after oral ingestion. Nanoencapsulation improves stability for anthocyanin, thus demonstrating the potential to be included in foods or used as dietary supplements, and current limitations, challenges, and future directions of anthocyanins' have also been discussed.

Anti-Inflammatory and Anti-Rheumatic Potential of Selective Plant Compounds by Targeting TLR-4/AP-1 Signaling: A Comprehensive Molecular Docking and Simulation Approaches

Plants are an important source of drug development and numerous plant derived molecules have been used in clinical practice for the ailment of various diseases. The Toll-like receptor-4 (TLR-4) signaling pathway plays a crucial role in inflammation including rheumatoid arthritis. The TLR-4 binds with pro-inflammatory ligands such as lipopolysaccharide (LPS) to induce the downstream signaling mechanism such as nuclear factor κappa B (NF-κB) and mitogen activated protein kinases (MAPKs). This signaling activation leads to the onset of various diseases including inflammation. In the present study, 22 natural compounds were studied against TLR-4/AP-1 signaling, which is implicated in the inflammatory process using a computational approach. These compounds belong to various classes such as methylxanthine, sesquiterpene lactone, alkaloid, flavone glycosides, lignan, phenolic acid, etc. The compounds exhibited different binding affinities with the TLR-4, JNK, NF-κB, and AP-1 protein due to the formation of multiple hydrophilic and hydrophobic interactions. With TLR-4, rutin had the highest binding energy (−10.4 kcal/mol), poncirin had the highest binding energy (−9.4 kcal/mol) with NF-κB and JNK (−9.5 kcal/mol), respectively, and icariin had the highest binding affinity (−9.1 kcal/mol) with the AP-1 protein. The root means square deviation (RMSD), root mean square fraction (RMSF), and radius of gyration (RoG) for 150 ns were calculated using molecular dynamic simulation (MD simulation) based on rutin’s greatest binding energy with TLR-4. The RMSD, RMSF, and RoG were all within acceptable limits in the MD simulation, and the complex remained stable for 150 ns. Furthermore, these compounds were assessed for the potential toxic effect on various organs such as the liver, heart, genotoxicity, and oral maximum toxic dose. Moreover, the blood–brain barrier permeability and intestinal absorption were also predicted using SwissADME software (Lausanne, Switzerland). These compounds exhibited promising physico-chemical as well as drug-likeness properties. Consequently, these selected compounds portray promising anti-inflammatory and drug-likeness properties.

Liquid Chromatography-High-Resolution Mass Spectrometry (LC-HRMS) Profiling of Commercial Enocianina and Evaluation of Their Antioxidant and Anti-Inflammatory Activity

Enocianina is an anthocyanin-rich extract obtained from grape pomace. It is widely used as a colorant in the food industry and, in addition to anthocyanins, it also contains a variety of polyphenols. To understand whether enocianina, besides its coloring effect, may offer potential health benefit applications, we aimed to fully characterize the profile of four commercial enocianinas and assess their radical scavenging, enzymatic, antioxidant, and anti-inflammatory activities. LC-ESI-MS/MS analysis identified 90 phytochemicals. The relative content of each anthocyanin was assessed by a semi-quantitative analysis, with malvidin derivatives being the most abundant. UV-VIS spectroscopy detected total amounts of polyphenols and anthocyanins of 23% and 3.24%, respectively, indicating that anthocyanins represent a minor fraction of total polyphenols. Multiple linear regression analysis indicated that the radical scavenging activity is related to the total polyphenol content and not to anthocyanins. All four enocianinas dose-dependently activate Nrf2, and such activity was correlated with catechol-containing polyphenol content. Finally, all enocianinas showed dose-dependent anti-inflammatory activity, which at the highest concentrations tested was closely related to the total polyphenol content and was explained by radical scavenging, Nrf2 activation, and other mechanisms related to the polyphenolic components.

Nanotechnology as a Tool to Mitigate the Effects of Intestinal Microbiota on Metabolization of Anthocyanins

Anthocyanins are an important group of phenolic compounds responsible for pigmentation in several plants. For humans, a regular intake is associated with a reduced risk of several diseases. However, molecular instability reduces the absorption and bioavailability of these compounds. Anthocyanins are degraded by external factors such as the presence of light, oxygen, temperature, and changes in pH ranges. In addition, the digestion process contributes to chemical degradation, mainly through the action of intestinal microbiota. The intestinal microbiota has a fundamental role in the biotransformation and metabolization of several dietary compounds, thus modifying the chemical structure, including anthocyanins. This biotransformation leads to low absorption of intact anthocyanins, and consequently, low bioavailability of these antioxidant compounds. Several studies have been conducted to seek alternatives to improve stability and protect against intestinal microbiota degradation. This comprehensive review aims to discuss the existing knowledge about the structure of anthocyanins while discussing human absorption, distribution, metabolism, and bioavailability after the oral consumption of anthocyanins. This review will highlight the use of nanotechnology systems to overcome anthocyanin biotransformation by the intestinal microbiota, pointing out the safety and effectiveness of nanostructures to maintain molecular stability.

Natural deep eutectic solvent (NADES): A strategy to improve the bioavailability of blueberry phenolic compounds in a ready-to-use extract

This study investigated whether a ready-to-use extract obtained using a natural deep eutectic solvent (NADES) affects the pharmacokinetic profile of blueberry phenolic compounds compared to organic solvent (SORG)-extracted compounds. SORG extract was administered as an aqueous solution after solvent removal. Wistar rats received a single dose of crude extract of blueberry obtained using NADES (CE-NADES) or SORG (CE-SORG), followed by LC-DAD-MS/MS analysis of blood and cecal feces. Non-compartmental pharmacokinetic analysis revealed that CE-NADES increased the bioavailability of anthocyanins by 140% compared to CE-SORG. CE-NADES increased the stability of phenolic compounds during in vitro digestion by delaying gastric chyme neutralization. These results suggest that besides being an eco-friendly solvent for the extraction of phytochemicals, choline chloride:glycerol:citric acid-based NADES can be used as a ready-to-use vehicle for increasing oral absorption of bioactive compounds such as anthocyanins.

Effects of α-Casein on the Absorption of Blueberry Anthocyanins and Metabolites in Rat Plasma Based on Pharmacokinetic Analysis

Blueberry anthocyanins are well known for their beneficial biological activities. However, the poor bioavailability of anthocyanins limits their functional capacity in vivo. Our current study aimed to detect the effects of α-casein on the absorption of blueberry anthocyanins and their metabolites in rats. Blueberry anthocyanins with and without α-casein were intragastrically administered to two groups of rats and their blood samples were collected within 24 h. Results illustrated that rapid absorption of anthocyanins was observed in the rat plasma, but their concentration was relatively low. With the complexation of α-casein, the maximum concentration (C_max) of bioavailable anthocyanins and metabolites could increase by 1.5-10.1 times (P < 0.05 or P < 0.01). The promotional effect on the plasma absorption of malvidin-3-O-galactoside and vanillic acid was outstanding with the C_max increasing from 0.032 to 0.323 and from 0.360 to 1.902 μg/mL, respectively (P < 0.01). Besides, the molecular docking models presented that anthocyanins could enter the structural cavity and interact with amino acid residues of α-casein, which was in accordance with the improved bioavailability of anthocyanins. Therefore, α-casein could assist more blueberry anthocyanins and their metabolites to enter blood circulation.

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.

Berry polyphenols metabolism and impact on human gut microbiota and health

Berries are rich in phenolic compounds such as phenolic acids, flavonols and anthocyanins. These molecules are often reported as being responsible for the health effects attributed to berries. However, their poor bioavailability, mostly influenced by their complex chemical structures, raises the question of their actual direct impact on health. The products of their metabolization, however, may be the most bioactive compounds due to their ability to enter the blood circulation and reach the organs. The main site of metabolization of the complex polyphenols to smaller phenolic compounds is the gut through the action of microorganisms, and reciprocally polyphenols and their metabolites can also modulate the microbial populations. In healthy subjects, these modulations generally lead to an increase in Bifidobacterium, Lactobacillus and Akkermansia, therefore suggesting a prebiotic-like effect of the berries or their compounds. Finally, berries have been demonstrated to alleviate symptoms of gut inflammation through the modulation of pro-inflammatory cytokines and have chemopreventive effects towards colon cancer through the regulation of apoptosis, cell proliferation and angiogenesis. This review recapitulates the knowledge available on the interactions between berries polyphenols, gut microbiota and gut health and identifies knowledge gaps for future research.

Preparation of Lipid-Soluble Bilberry Anthocyanins through Acylation with Cinnamic Acids and their Antioxidation Activities

To enable the use of anthocyanins in food with high oil content, bilberry anthocyanins were acylated with cinnamic acids to address their poor lipid solubility. Structural analyses based on Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and ¹H nuclear magnetic resonance analyses indicated that cinnamic acids were efficiently grafted onto 6-OH of glucoside and galactoside and 5-OH of arabinose through an esterification reaction. The higher the dose of the acylating agent, the higher the acylation degree (AD) and the lower the total anthocyanidin content (TAC) of bilberry anthocyanins. An-Ci4 presented the highest AD value (6.61%), and An-Ci3 exhibited the lowest TAC value (50.16 mg/g). After acylating with lipophilic cinnamic acids, the lipid solubility of acylated bilberry anthocyanins significantly improved. The color of the native bilberry anthocyanin solution dissolved in ethyl acetate and dioxane was transparent. By contrast, the acylated anthocyanin solution dissolved in these solvents was unmistakably red. In terms of the antioxidant activity, acylated bilberry anthocyanins demonstrated inferior performance in 2,2-diphenyl-1-picrylhydrazyl (DPPH) clearance but a better inhibition ratio in β-carotene bleaching assay compared with native bilberry anthocyanins. As AD value increased, the DPPH clearance of acylated anthocyanins decreased and their inhibition ratio increased in β-carotene bleaching assay.

Anthocyanins As Modulators of Cell Redox-Dependent Pathways in Non-Communicable Diseases

Chronic Noncommunicable Diseases (NCDs), mostly represented by cardiovascular diseases, diabetes, chronic pulmonary diseases, cancers, and several chronic pathologies, are one of the main causes of morbidity and mortality, and are mainly related to the occurrence of metabolic risk factors. Anthocyanins (ACNs) possess a wide spectrum of biological activities, such as anti-inflammatory, antioxidant, cardioprotective and chemopreventive properties, which are able to promote human health. Although ACNs present an apparent low bioavailability, their metabolites may play an important role in the in vivo protective effects observed. This article directly addresses the scientific evidences supporting that ACNs could be useful to protect human population against several NCDs not only acting as antioxidant but through their capability to modulate cell redox-dependent signaling. In particular, ACNs interact with the NF-κB and AP-1 signal transduction pathways, which respond to oxidative signals and mediate a proinflammatory effect, and the Nrf2/ARE pathway and its regulated cytoprotective proteins (GST, NQO, HO-1, etc.), involved in both cellular antioxidant defenses and elimination/inactivation of toxic compounds, so countering the alterations caused by conditions of chemical/oxidative stress. In addition, supposed crosstalks could contribute to explain the protective effects of ACNs in different pathological conditions characterized by an altered balance among these pathways. Thus, this review underlines the importance of specific nutritional molecules for human health and focuses on the molecular targets and the underlying mechanisms of ACNs against various diseases.

Effect of Blueberry Consumption on Cardiometabolic Health Parameters in Men with Type 2 Diabetes: An 8-Week, Double-Blind, Randomized, Placebo-Controlled Trial

BACKGROUND

Blueberries are dietary sources of polyphenols, specifically anthocyanins. Anthocyanins have been identified as having a strong association with type 2 diabetes risk reduction; however, to date few human clinical trials have evaluated the potential beneficial health effects of blueberries in populations with type 2 diabetes.

OBJECTIVES

We investigated the effects of blueberry consumption for 8 wk on cardiometabolic parameters in men with type 2 diabetes.

METHODS

In a double-blind, parallel-arm, randomized controlled trial, 52 men who are US veterans [mean baseline characteristics: age, 67 y (range: 51-75 y); weight, 102 kg (range: 80-130 kg); BMI (in kg/m2), 34 (range: 26-45)] were randomly assigned to 1 of 2 intervention groups. The interventions were either 22 g freeze-dried blueberries or 22 g placebo. The study participants were asked to consume 11 g freeze-dried blueberries or placebo with each of their morning and evening meals along with their typical diet.

RESULTS

Mean ± SE hemoglobin A1c (7.1% ± 0.1% compared with 7.5% ± 0.2%; P = 0.03), fructosamine (275.5 ± 4.1 compared with 292.4 ± 7.9 µmol/L; P = 0.04), triglycerides (179.6 ± 10.1 compared with 199.6 ± 19.9 mg/dL; P = 0.03), aspartate transaminase (23.2 ± 1.4 compared with 30.5 ± 2.7 units/L; P = 0.02), and alanine transaminase (35.6 ± 1.5 compared with 48.3 ± 2.9 units/L; P = 0.0003) were significantly lower for those consuming blueberries for 8 wk than for those consuming the placebo. Fasting plasma glucose concentrations; serum insulin, total cholesterol, LDL-cholesterol, HDL-cholesterol, and C-reactive protein concentrations; blood pressure; and body weight were not significantly different after 8 wk consumption of blueberries compared with the placebo.

CONCLUSIONS

Consumption of 22 g freeze-dried blueberries for 8 wk may beneficially affect cardiometabolic health parameters in men with type 2 diabetes.This trial was registered at clinicaltrials.gov as NCT02972996.

GLUT1 and GLUT3 involvement in anthocyanin gastric transport- Nanobased targeted approach

Anthocyanins may protect against a myriad of human diseases. However few studies have been conducted to evaluate their bioavailability so their absorption mechanism remains unclear. This study aimed to evaluate the role of two glucose transporters (GLUT1 and GLUT3) in anthocyanins absorption in the human gastric epithelial cells (MKN-28) by using gold nanoparticles to silence these transporters. Anthocyanins were purified from purple fleshed sweet potatoes and grape skin. Silencing of GLUT1 and/or GLUT3 mRNA was performed by adding AuNP@GLUT1 and/or AuNP@GLUT3 to MKN-28 cells. Downregulation of mRNA expression occurred concomitantly with the reduction in protein expression. Malvidin-3-O-glucoside (Mv3glc) transport was reduced in the presence of either AuNP@GLUT1 and AuNP@GLUT3, and when both transporters were blocked simultaneously. Peonidin-3-(6'-hydroxybenzoyl)-sophoroside-5-glucoside (Pn3HBsoph5glc) and Peonidin-3-(6'-hydroxybenzoyl-6″-caffeoyl)-sophoroside-5-glucoside (Pn3HBCsoph5glc) were assayed to verify the effect of the sugar moiety esterification at glucose B in transporter binding. Both pigments were transported with a lower transport efficiency compared to Mv3glc, probably due to steric hindrance of the more complex structures. Interestingly, for Pn3HBCsoph5glc although the only free glucose is at C5 and the inhibitory effect of the nanoparticles was also observed, reinforcing the importance of glucose on the transport regardless of its position or substitution pattern. The results support the involvement of GLUT1 and GLUT3 in the gastric absorption of anthocyanins.

Daily Consumption of Bilberry ( Vaccinium myrtillus L.) Extracts Increases the Absorption Rate of Anthocyanins in Rats

The effects of daily consumption of anthocyanins on bioavailability has remained unclear. In this study, we evaluated whether daily consumption affects the absorption rate of anthocyanins in rats when consumed during the active and sleep phase. Eighty rats were randomly divided into two groups. The first group consumed AIN-93G control diets, and the second group consumed AIN-93G diets containing 1% bilberry extract for 2 weeks. After 12 h fast, anthocyanins were not detected in plasma of rats. Bilberry extract (500 mg/kg body weight) was then orally administered at the beginning of the diurnal light period (ZT0, sleep phase) or at the end of the diurnal light period (ZT12, active phase). Blood concentrations of anthocyanins peaked 1 h after administration in both groups. Maximum blood concentration in rats that consumed bilberry extract daily (852 nM) was higher than that in control rats (630 nM) when the extract was administered at ZT0 but not at ZT12. Daily consumption of anthocyanins increases their absorption rate, but this effect is limited to the beginning of the sleep phase.

Effect of dark sweet cherry powder consumption on the gut microbiota, short-chain fatty acids, and biomarkers of gut health in obese db/db mice

Cherries are fruits containing fiber and bioactive compounds (e.g., polyphenolics) with the potential of helping patients with diabetes and weight disorders, a phenomenon likely related to changes in the complex host-microbiota milieu. The objective of this study was to investigate the effect of cherry supplementation on the gut bacterial composition, concentrations of caecal short-chain fatty acids (SCFAs) and biomarkers of gut health using an in vivo model of obesity. Obese diabetic (db/db) mice received a supplemented diet with 10% cherry powder (supplemented mice, n = 12) for 12 weeks; obese (n = 10) and lean (n = 10) mice served as controls and received a standard diet without cherry. High-throughput sequencing of the 16S rRNA gene and quantitative real-time PCR (qPCR) were used to analyze the gut microbiota; SCFAs and biomarkers of gut health were also measured using standard techniques. According to 16S sequencing, supplemented mice harbored a distinct colonic microbiota characterized by a higher abundance of mucin-degraders (i.e., Akkermansia) and fiber-degraders (the S24-7 family) as well as lower abundances of Lactobacillus and Enterobacteriaceae. Overall this particular cherry-associated colonic microbiota did not resemble the microbiota in obese or lean controls based on the analysis of weighted and unweighted UniFrac distance metrics. qPCR confirmed some of the results observed in sequencing, thus supporting the notion that cherry supplementation can change the colonic microbiota. Moreover, the SCFAs detected in supplemented mice (caproate, methyl butyrate, propionate, acetate and valerate) exceeded those concentrations detected in obese and lean controls except for butyrate. Despite the changes in microbial composition and SCFAs, most of the assessed biomarkers of inflammation, oxidative stress, and intestinal health in colon tissues and mucosal cells were similar in all obese mice with and without supplementation. This paper shows that dietary supplementation with cherry powder for 12 weeks affects the microbiota and the concentrations of SCFAs in the lower intestinal tract of obese db/db diabetic mice. These effects occurred in absence of differences in most biomarkers of inflammation and other parameters of gut health. Our study prompts more research into the potential clinical implications of cherry consumption as a dietary supplement in diabetic and obese human patients.

Approaching Pharmacological Space: Events and Components

With a view to introducing the concept of pharmacological space and its potential applications in investigating and predicting the toxic mechanisms of xenobiotics, this opening chapter describes the logical relations between conformational behavior, physicochemical properties and binding spaces, which are seen as the three key elements composing the pharmacological space. While the concept of conformational space is routinely used to encode molecular flexibility, the concepts of property spaces and, particularly, of binding spaces are more innovative. Indeed, their descriptors can find fruitful applications (a) in describing the dynamic adaptability a given ligand experiences when inserted into a specific environment, and (b) in parameterizing the flexibility a ligand retains when bound to a biological target. Overall, these descriptors can conveniently account for the often disregarded entropic factors and as such they prove successful when inserted in ligand- or structure-based predictive models. Notably, and although binding space parameters can clearly be derived from MD simulations, the chapter will illustrate how docking calculations, despite their static nature, are able to evaluate ligand's flexibility by analyzing several poses for each ligand. Such an approach, which represents the founding core of the binding space concept, can find various applications in which the related descriptors show an impressive enhancing effect on the statistical performances of the resulting predictive models.