Influence of diabetes on plasma pharmacokinetics and brain bioavailability of grape polyphenols and their phase II metabolites in the Zucker diabetic fatty rat

Crop, Host, and Gut Microbiome Variation Influence Precision Nutrition: An Example of Blueberries

Epidemiological studies have shown associations between polyphenol-rich fruit intake and bone health, and preclinical studies have shown that blueberries improve bone health. To determine the genotype and dose of blueberries that are effective in ameliorating age-related bone loss, a multi-institutional team of investigators performed in vitro, preclinical, and clinical studies on blueberry varieties that differed in flavonoid profiles. Principal component analysis was used to select blueberry genotypes that varied in anthocyanin profiles. Total phenolic content did not predict the bioavailability of polyphenolic compounds in rats. A range in bioavailability was observed in individual polyphenolic compounds across genotypes. Both alpha and beta diversity analyses indicated that gut microbiome profiles varied with blueberry dose in rats. Additionally, the identification of specific taxa, such as Prevotellaceae_UCG-001 and Coriobacteriales, increasing after blueberry consumption adds to the mounting evidence of their role in polyphenol metabolism. All of the sources of variation can inform blueberry breeding practices to influence precision nutrition.

Anthocyanins from Aronia melanocarpa Bound to Amylopectin Nanoparticles: Tissue Distribution and In Vivo Oxidative Damage Protection

The in vivo applications of anthocyanins are limited by their instability. Nano-encapsulation using amylopectin nanoparticles (APNPs) stabilizes anthocyanins to deliver them to tissues to ameliorate their physiological functions. Herein, rats are fed four Aronia melanocarpa anthocyanins encapsulated with APNPs, and their subsequent distributions and bioactivity in nine tissues are revealed using UHPLC-MS. Among digestive tissues, the concentration of the APNP-protected cyanidin 3-O-arabinoside in the stomach is 134.54% of that of the free anthocyanin, while among non-digestive tissues, the APNP-protected cyanidin 3-O-glucoside concentration in the lungs improved by 125.49%. Concentration maxima "double peaks" in the liver and kidney arise from different modes of transport. Sustained release of anthocyanins from anthocyanin-APNPs and stable concentration curves suggest controlled delivery, with most APNPs consumed in the digestive system. APNPs did not affect the overall anthocyanin absorption time or tissues. The superoxide dismutase and malondialdehyde concentrations indicate that APNPs enhance the oxidative damage protection in vivo.

Hypoglycemic medicines in the treatment of Alzheimer's disease: Pathophysiological links between AD and glucose metabolism

Alzheimer's Disease (AD) is a global chronic disease in adults with beta-amyloid (Aβ) deposits and hyperphosphorylated tau protein as the pathologic characteristics. Although the exact etiology of AD is still not fully elucidated, aberrant metabolism including insulin signaling and mitochondria dysfunction plays an important role in the development of AD. Binding to insulin receptor substrates, insulin can transport through the blood-brain barrier (BBB), thus mediating insulin signaling pathways to regulate physiological functions. Impaired insulin signaling pathways, including PI3K/Akt/GSK3β and MAPK pathways, could cause damage to the brain in the pathogenesis of AD. Mitochondrial dysfunction and overexpression of TXNIP could also be causative links between AD and DM. Some antidiabetic medicines may have benefits in the treatment of AD. Metformin can be beneficial for cognition improvement in AD patients, although results from clinical trials were inconsistent. Exendin-4 may affect AD in animal models but there is a lack of clinical trials. Liraglutide and dulaglutide could also benefit AD patients in adequate clinical studies but not semaglutide. Dipeptidyl peptidase IV inhibitors (DPP4is) such as saxagliptin, vildagliptin, linagliptin, and sitagliptin could boost cognitive function in animal models. And SGLT2 inhibitors such as empagliflozin and dapagliflozin were also considerably protective against new-onset dementia in T2DM patients. Insulin therapy is a promising therapy but some studies indicated that it may increase the risk of AD. Herbal medicines are helpful for cognitive function and neuroprotection in the brain. For example, polyphenols, alkaloids, glycosides, and flavonoids have protective benefits in cognition function and glucose metabolism. Focusing on glucose metabolism, we summarized the pharmacological mechanism of hypoglycemic drugs and herbal medicines. New treatment approaches including antidiabetic synthesized drugs and herbal medicines would be provided to patients with AD. More clinical trials are needed to produce definite evidence for the effectiveness of hypoglycemic medications.

Phenolic composition of grape pomace and its metabolism

Grape pomace is the most important residual after wine making, and it is considered to be a very abundant source for the extraction of a wide range of polyphenols. These polyphenols exhibit a variety of bioactivities, such as antioxidant, anti-inflammatory, and anti-cancer. They are also beneficial in alleviating metabolic syndrome and regulating intestinal flora, etc. These health effects are most likely contributed by polyphenol metabolite, which are formed by the grape pomace phenolics after a complex metabolic process in vivo. Therefore, understanding the phenolic composition of grape pomace and its metabolism is the basis for an in-depth study of the biological activity of grape pomace polyphenols. In this paper, we first summarize the composition of phenolics in grape pomace, then review the recent studies on the metabolism of grape pomace phenolics, including changes in phenolics in the gastrointestinal tract, their pharmacokinetics in the systemic circulation, the tissue distribution of phenolic metabolites, and the beneficial effects of metabolites on intestinal health, and finally summarize the effects of human health status and dietary fiber on the metabolism of grape polyphenols. It is expected to provide help for the in-depth research on the metabolism and biological activity of grape pomace polyphenol extracts, and to provide theoretical support for the development and utilization of grape pomace.

A Screening of Native (Poly)phenols and Gut-Related Metabolites on 3D HCT116 Spheroids Reveals Gut Health Benefits of a Flavan-3-ol Metabolite

SCOPE

Epidemiological evidence suggests that a reduced risk of colorectal cancer (CRC) is correlated with high consumption of fruits and vegetables, which are major sources of fiber and phytochemicals, such as flavan-3-ols. However, it remains unknown how these phytochemicals and their specific gut-related metabolites may alter cancer cell behavior.

METHODS AND RESULTS

A focused screening using native (poly)phenols and gut microbial metabolites (GMMs) on 3D HCT116 spheroids is carried out using a high-throughput imaging approach. Dose-responses, IC50 , and long-term exposure are calculated for the most promising native (poly)phenols and GMMs. As a result, this research shows that (poly)phenol catabolites may play a key role in preventing cancer propagation. Indeed, µM concentration levels of (4R)-5-(3',4'-dihydroxyphenyl)-γ-valerolactone significantly decrease spheroid size at early stages of spheroid aggregation and gene expression of matrix metalloproteinases.

CONCLUSION

A chronic exposure to (4R)-5-(3',4'-dihydroxyphenyl)-γ-valerolactone may lead to a reduced CRC risk. Daily intake of monomeric, oligomeric, and polymeric flavan-3-ols may increase the colonic concentrations of this metabolite, and, in turn, this compound may act locally interacting with intestinal epithelial cells, precancerous and cancer cells.

Investigating Polyphenol Nanoformulations for Therapeutic Targets against Diabetes Mellitus

Diabetes mellitus (DM) is a fatal metabolic disorder, and its prevalence has escalated in recent decades to a greater extent. Since the incidence and severity of the disease are constantly increasing, plenty of therapeutic approaches are being considered as a promising solution. Many dietary polyphenols have been reported to be effective against diabetes along with its accompanying vascular consequences by targeting multiple therapeutic targets. Additionally, the biocompatibility of these polyphenols raises questions about their use as pharmacological mediators. Nevertheless, the pharmacokinetic and biopharmaceutical properties of these polyphenols limit their clinical benefit as therapeutics. Pharmaceutical industries have attempted to improve compliance and therapeutic effects. However, nanotechnological approaches to overcome the pharmacokinetic and biopharmaceutical barriers associated with polyphenols as antidiabetic medications have been shown to be effective to improve clinical compliance and efficacy. Therefore, this review highlighted a comprehensive and up-to-date assessment of polyphenol nanoformulations in the treatment of diabetes and vascular consequences.

Bioaccessibility, gut microbial metabolism and intestinal transport of phenolics from 100% Concord grape juice and whole grapes are similar in a simulated digestion and fecal fermentation model

Phenolic rich 100% grape juice has been associated with many health benefits, but its place in dietary guidance is controversial relative to whole fruit. Direct comparisons of phenolic profiles and bioavailability between these food forms are needed. Phenolic bioaccessibility and metabolism from Concord (CG) and Niagara (NG) grapes and corresponding 100% juices were investigated using an in vitro digestion coupled with anaerobic gut fermentation model. Intestinal transport of resulting bioaccessible phenolics and microbial metabolites was estimated using a Caco-2 cell model. Total bioaccessible phenolics from both upper and lower digestion were similar (P > 0.05) between NG (400.9 ± 26.3 μmol per 100 g) and NGJ (349.5 ± 8.3 μmol per 100 g) and significantly different (P < 0.05) between CG (417.2 ± 24.4 μmol per 100 g) and CGJ (294.3 ± 45.4 μmol per 100 g) total cellular transport of phenolics was similar (P > 0.05) between whole grapes (89.4 ± 5.3 μmol per 100 g for CG, and 71.8 ± 2.4 μmol per 100 g for NG) and 100% juices (88.0 ± 5.6 μmol per 100 g for CGJ, and 85.3 ± 9.4 μmol per 100 g for NGJ). Differences were observed between the location of phenolic metabolism, bioaccessibility and subsequent cellular transport of individual phenolics between grapes and juice matrices. Specifically, greater amounts of phenolics were transported from grape juices than whole grapes from the upper tract. However, cumulative bioaccessibility and transport from upper and lower GI digestion/fermentation together indicates that the absorbable phenolics from 100% grape juice is similar to that of whole grapes, suggesting that phenolic-mediated health benefits from consumption of whole fruit and juice may be similar.

Comparative analysis of absorbed ingredients and metabolites, and pharmacokinetic studies of Zhimu-Huangbai herb pair in the plasma of normal and type 2 diabetes mellitus rats by UHPLC-linear trap quadrupole-orbitrap MS and LC-MS/MS

A new rapid ultra-high-performance liquid chromatography coupled with linear trap quadrupole orbitrap mass spectrometry method was established for the qualitative analysis of absorbed ingredients and metabolites of Zhimu-Huangbai herb pair, which is used to treat type 2 diabetes mellitus. A total of 16 absorbed ingredients and 11 metabolites were identified in normal and type 2 diabetes mellitus rats, respectively. Such findings indicated that the diabetic model had no effect on the type of components in plasma. Seven absorbed ingredients and 11 metabolites were first identified after the oral administration of Zhimu-Huangbai herb pair. Thereafter, ultra-high-performance liquid chromatography coupled with linear trap quadrupole orbitrap mass spectrometry and liquid chromatography-API4000⁺ triple quadrupole mass spectrometer methods were established and validated for pharmacokinetic comparative studies of seven major bioactive components in normal and type 2 diabetes mellitus rats. Partial pharmacokinetic parameters in the plasma of type 2 diabetes mellitus rats were significantly different from those in normal rats. To our knowledge, this is the first comparison of absorbed ingredients and metabolites of Zhimu-Huangbai herb pair, and its use in pharmacokinetic studies between normal and type 2 diabetes mellitus rats. Ultimately, our findings provide insights into the clinical usage of Zhimu-Huangbai herb pair.

Changes in polyphenol serum levels and cognitive performance after dietary supplementation with Concord grape juice in veterans with Gulf War Illness

AIMS

We investigated whether the consumption of Concord grape juice (CGJ) was associated with increased bioavailability of serum metabolites and their potential impact on cognitive performance in Veterans with Gulf War Illness (GWI).

MAIN METHODS

Twenty-six veterans were selected from a cohort of 36 enrolled in a 24-week randomized, double-blind, Phase I/IIA clinical trial exploring whether the consumption of Concord grape juice (CGJ) was tolerable and safe in Veterans with GWI and improved cognitive function and fatigue. These 26 veterans were selected based on their completion of the entire 24-week protocol and documented adherence to the study beverage ≥80%. Differences in serum metabolite levels between CGJ and placebo at midpoint and endpoint were evaluated using two-way repeated measures ANOVA with post hoc Sidak's multiple comparison test. Bivariate correlations to assess for possible relationships between change in serum metabolite levels and change in cognitive function as measured by the Halstead Category Test-Russell Revised Version (RCAT) were also conducted.

KEY FINDINGS

Seventy-six metabolites were identified and quantified in this study, with three (cyanidin-glucuronide, me-cyanidin-glucuronide, and me-malvidin-glucuronide) found to be significantly higher (p < 0.05) in the CGJ group compared to placebo at 24 weeks. Significant associations between changes in cognitive function and changes in serum levels of epicatechin-sulphate (r = 0.48, p = 0.01) and petunidin-glucuronide (r = 0.53, p < 0.01) from baseline to 24 weeks were also observed.

SIGNIFICANCE

Our data suggest that dietary supplementation with CGJ is associated with increased bioavailability of specific phenolic metabolites, some of which may be correlated with cognitive performance.

Development of grape polyphenols as multi-targeting strategies for Alzheimer's disease

Alzheimer's disease (AD) is by far the most prevalent neurodegenerative disease of aging and is a major burden for patients, caregivers, and the overall health care system. The complexity of AD pathophysiology and the lack of deep understanding of disease mechanisms impeded the development of AD therapy. Currently approved treatments for AD only modestly improve cognitive function but do not modify disease course. The lack of pharmacological approaches has led to the consideration of alternative strategies to prevent or to slow down the progression of AD. There has been a growing interest in the scientific community regarding the impact of diet and nutrition on AD. Grape derived nutraceuticals and phytochemical compounds have demonstrated anti-amyloidogenic, antioxidative, anti-inflammatory and neurotrophic properties and present as potential novel strategies for AD treatment. In this review, we summarize promising grape derived polyphenols that have been shown to modulate AD pathophysiology including amyloid plaques and neurofibrillary tangles formation, AD-induced oxidative stress, neuroinflammation and synaptic dysfunction.

Lactucaxanthin protects retinal pigment epithelium from hyperglycemia-regulated hypoxia/ER stress/VEGF pathway mediated angiogenesis in ARPE-19 cell and rat model

Hyperglycemia mediated perturbations in biochemical pathways induce angiogenesis in diabetic retinopathy (DR) pathogenesis. The present study aimed to investigate the protective effects of lactucaxanthin, a predominant lettuce carotenoid, on hyperglycemia-mediated activation of angiogenesis in vitro and in vivo diabetic model. ARPE-19 cells cultured in 30 mM glucose concentration were treated with lactucaxanthin (5 μM and 10 μM) for 48 h. They were assessed for antioxidant enzyme activity, mitochondrial membrane potential, reactive oxygen species, and cell migration. In the animal experiment, streptozotocin-induced diabetic male Wistar rats were gavaged with lactucaxanthin (200 μM) for 8 weeks. Parameters like animal weight gain, feed intake, water intake, urine output, and fasting blood glucose level were monitored. In both models, lutein-treated groups were considered as a positive control. Hyperglycemia-mediated angiogenic marker expressions in ARPE-19 and retina of diabetic rats were quantified through the western blot technique. Expression of hypoxia, endoplasmic reticulum stress markers, and vascular endothelial growth factor were found to be augmented in the hyperglycemia group compared to control (P < 0.05). Hyperglycemia plays a crucial role in increasing cellular migration and reactive oxygen species besides disrupting tight junction protein. Compared to lutein, lactucaxanthin aids retinal pigment epithelium (RPE) function from hyperglycemia-induced stress conditions via downregulating angiogenesis markers expression. Lactucaxanthin potentiality observed in protecting tight junction protein expression via modulating reactive oxygen species found to conserve RPE integrity. Results demonstrate that lactucaxanthin exhibits robust anti-angiogenic activity for the first time and, therefore, would be useful as an alternative therapy to prevent or delay DR progression.

The Role of High-Resolution Analytical Techniques in the Development of Functional Foods

The approaches based on high-resolution analytical techniques, such as nuclear magnetic resonance or mass spectrometry coupled to chromatographic techniques, have a determining role in several of the stages necessary for the development of functional foods. The analyses of botanical extracts rich in bioactive compounds is one of the fundamental steps in order to identify and quantify their phytochemical composition. However, the compounds characterized in the extracts are not always responsible for the bioactive properties because they generally undergo metabolic reactions before reaching the therapeutic targets. For this reason, analytical techniques are also applied to analyze biological samples to know the bioavailability, pharmacokinetics and/or metabolism of the compounds ingested by animal or human models in nutritional intervention studies. In addition, these studies have also been applied to determine changes of endogenous metabolites caused by prolonged intake of compounds with bioactive potential. This review aims to describe the main types and modes of application of high-resolution analytical techniques in all these steps for functional food development.

Simultaneous determination of five alkaloids from Rauvolfia vomitoria in rat plasma by LC-MS/MS: Application to a comparative pharmacokinetic study in normal and type 2 diabetic rats

Rauvolfia vomitoria is widely distributed in the tropical regions of Africa and Asia, and has been used in traditional folk medicine in China. Indole alkaloids were found to be major bioactive components, while the effects of diabetes mellitus on the pharmacokinetic parameters of the components have not been reflected in vivo. In this study, an efficient and sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous determination of five ingredients of R. vomitoria in rats. Detection was implemented in multiple-reaction-monitoring mode with an electrospray positive-ionization source. Validation parameters were all in accordance with the current criterion. The established method was effectively employed to compare the pharmacokinetic behaviors of five alkaloids (reserpine, yohimbine, ajmaline, ajmalicine, and serpentine) between normal and type 2 diabetic rats. The single-dose pharmacokinetic parameters of the five alkaloids were determined in normal and diabetic rats after oral administration of 100 and 200 mg/kg body weight. The results indicated that diabetes mellitus significantly altered the pharmacokinetic characteristics of yohimbine, ajmaline, and ajmalicine after oral administration in rats. This is an attempt to provide some evidence for clinicians that may serve as a guide for the use of antidiabetic medicine in clinical practice.

Flavonoids as an Intervention for Alzheimer's Disease: Progress and Hurdles Towards Defining a Mechanism of Action

Attempts to develop a disease modifying intervention for Alzheimer's disease (AD) through targeting amyloid β (Aβ) have so far been unsuccessful. There is, therefore, a need for novel therapeutics against alternative targets coupled with approaches which may be suitable for early and sustained use likely required for AD prevention. Numerous in vitro and in vivo studies have shown that flavonoids can act within processes and pathways relevant to AD, such as Aβ and tau pathology, increases in BDNF, inflammation, oxidative stress and neurogenesis. However, the therapeutic development of flavonoids has been hindered by an ongoing lack of clear mechanistic data that fully takes into consideration metabolism and bioavailability of flavonoids in vivo. With a focus on studies that incorporate these considerations into their experimental design, this review will evaluate the evidence for developing specific flavonoids as therapeutics for AD. Given the current lack of success of anti-Aβ targeting therapeutics, particular attention will be given to flavonoid-mediated regulation of tau phosphorylation and aggregation, where there is a comparable lack of study. Reflecting on this evidence, the obstacles that prevent therapeutic development of flavonoids will be examined. Finally, the significance of recent advances in flavonoid metabolomics, modifications and influence of the microbiome on the therapeutic capacity of flavonoids in AD are explored. By highlighting the potential of flavonoids to target multiple aspects of AD pathology, as well as considering the hurdles, this review aims to promote the efficient and effective identification of flavonoid-based approaches that have potential as therapeutic interventions for AD.

Early-life supplementation of grape polyphenol extract promotes polyphenol absorption and modulates the intestinal microbiota in association with the increase in mRNA expression of the key intestinal barrier genes

Early-life nutritional supplementation can dramatically influence health status. Dietary polyphenols are a widespread group of phytochemicals with potential bioactive functions. However, how polyphenol intake during early life affects health status remains largely unknown. Mice aged 3- and 6-weeks were used to investigate how grape polyphenol extract (GPE) administration during early life altered polyphenol absorption, the intestinal microbiota, and the intestinal barrier. After a 2-week GPE supplementation, there were more diverse polyphenol metabolites in the plasma of 3-week-old mice than in the plasma of 6-week-old mice. Correspondingly, GPE supplementation increased the mRNA expression of genes related to polyphenol absorption in 3-week-old mice but not 6-week-old mice. Early-life GPE administration also stimulated the key genes of the small intestinal barrier in mice. Moreover, the key genes of the small intestinal barrier were positively associated with the genes related to polyphenol absorption in the small intestine of 3-week-old mice. In addition, fecal Akkermansia and Lactobacillus were increased, as evidenced by 16S rRNA gene sequencing. As a result, the acetate and butyrate production in the large intestinal content was enhanced, and the mRNA expression of the key genes involved in the large intestinal barrier was also increased. Thus, our study demonstrates that dietary polyphenol intake in early life induces improvements in polyphenol absorption, the intestinal microbiota, and the intestinal barrier, suggesting the importance of polyphenol-rich nutritional programming during early life on health status.

Chokeberry anthocyanins and their metabolites ability to cross the blood-cerebrospinal fluid barrier

The aim of this study was to determine whether anthocyanins and their phase II metabolites permeate the blood-cerebrospinal fluid barrier (B-CSF-B) of sheep and to profile these compounds in sheep biofluids after chokeberry intraruminal administration. Anthocyanins were analyzed using micro-HPLC-MS/MS. After chokeberry administration, anthocyanins were absorbed and occurred in body fluids mainly in the form of methylated, glucuronidated, and sulfated derivatives (in total, 21 derivatives were identified). The study showed that anthocyanins penetrated the B-CSF-B and their change in profile and concentration in the cerebrospinal fluid (CSF) resulted from fluctuations in concentrations of these compounds in blood plasma, although the presence of various cyanidin derivatives in CSF also depended on their chemical structure. The biological fate of chokeberry anthocyanins, from absorption into blood to penetration into CSF, was tracked to facilitate the design of further experimental procedures to determine the biological properties of these compounds, including potentially neuroprotective activities.

Resveratrol Modulates the Gut-Brain Axis: Focus on Glucagon-Like Peptide-1, 5-HT, and Gut Microbiota

Resveratrol is a natural polyphenol that has anti-aging and anti-inflammatory properties against stress condition. It is reported that resveratrol has beneficial functions in various metabolic and central nervous system (CNS) diseases, such as obesity, diabetes, depression, and dementia. Recently, many researchers have emphasized the connection between the brain and gut, called the gut-brain axis, for treating both CNS neuropathologies and gastrointestinal diseases. Based on previous findings, resveratrol is involved in glucagon-like peptide 1 (GLP-1) secreted by intestine L cells, the patterns of microbiome in the intestine, the 5-hydroxytryptamine (5-HT) level, and CNS inflammation. Here, we review recent evidences concerning the relevance and regulatory function of resveratrol in the gut-brain axis from various perspectives. Here, we highlight the necessity for further study on resveratrol's specific mechanism in the gut-brain axis. We present the potential of resveratrol as a natural therapeutic substance for treating both neuropathology and gastrointestinal dysfunction.

Cyanidin-3-glucoside as a possible biomarker of anthocyanin-rich berry intake in body fluids of healthy humans: a systematic review of clinical trials

Context

Anthocyanins are phenolic compounds found in berries. They exhibit promising health benefits in humans, but no accurate biomarkers of berry intake have been identified thus far.

Objective

The aim of this systematic review is to propose a biomarker of anthocyanin-rich berry intake in human plasma and urine.

Data Sources

PubMed and Cochrane databases were searched from January 2008 to January 2019.

Study Selection

Databases were searched for human intervention studies that assessed the presence of anthocyanins in human body fluids using high-throughput techniques. Non-English articles and studies publishing targeted analyses were excluded.

Data Extraction

Ten clinical trials, in which 203 phenolic compounds were identified, were included and assessed qualitatively. The following criteria were used to identify biomarkers of berry intake: frequency, plausibility, dose-response, time response, robustness, reliability, stability, analytical performance, and reproducibility. Sensitivity and specificity of potential biomarkers were determined by the receiver operating characteristic curve.

Results

Of the 203 phenolic compounds identified in human samples, the anthocyanin cyanidin-3-glucoside was the molecule found most frequently in urine (58.06%) and plasma (69.49%). Cyanidin-3-glucoside fulfills the essential criterion of plausibility as well as the dose-response, time response, stability, and analytical performance criteria. Its positive predictive value is 74% (P = 0.210) in plasma, which is acceptable, and 61.7% (P = 0.402) in urine.

Conclusions

Current evidence suggests that cyanidin-3-glucoside is a potential biomarker of anthocyanin-rich berry intake in plasma and urine of healthy humans.

PROSPERO registration number

CRD42018096796.

The Blood-Cerebrospinal Fluid Barrier Is Selective for Red Cabbage Anthocyanins and Their Metabolites

The study aim was to determine whether strongly bioactive hydrophilic red cabbage anthocyanins possess the ability to cross the blood-cerebrospinal fluid barrier (blood-CSF barrier) and whether there is a selectivity of this barrier toward these compounds. To fulfill objectives, red cabbage preparation, containing nonacylated and acylated anthocyanins, was administered to 16 sheep with implanted cannulas into the brain third ventricle, and next, within 10 h, blood, urine, and the cerebrospinal fluid (CSF) were collected and analyzed with HPLC-MS/MS. Though, in blood plasma and urine after red cabbage intake, both, acylated and nonacylated anthocyanins and their metabolites occurred, but only nonacylated derivatives were present in the CSF, and their changes in the profile and concentration in the CSF resulted from the fluctuation of these pigments' concentration and profile in blood, their different abilities to permeate via the blood-CSF barrier, and their transformations in this barrier. Results indicate that the blood-CSF barrier is selective for red cabbage anthocyanins.

Influence of Diet-Induced Obesity on the Bioavailability and Metabolism of Raspberry Ketone (4-(4-Hydroxyphenyl)-2-Butanone) in Mice

OBJECTIVES

Raspberry ketone (RK) is the primary aroma compound in red raspberries and a dietary supplement for weight loss. This work aims to 1) compare RK bioavailability in male versus female, normal-weight versus obese mice; 2) characterize RK metabolic pathways.

METHODS

Study 1: C57BL/6J male and female mice fed a low-fat diet (LFD; 10% fat) receive a single oral gavage dose of RK (200 mg kg-1 ). Blood, brain, and white adipose tissue (WAT) are collected over 12 h. Study 2: Male mice are fed a LFD or high-fat diet (45% fat) for 8 weeks before RK dosing. Samples collected are analyzed by UPLC-MS/MS for RK and its metabolites.

RESULTS

RK is rapidly absorbed (Tmax  ≈ 15 min), and bioconverted into diverse metabolites in mice. Total bioavailability (AUC0-12 h ) is slightly lower in females than males (566 vs 675 nmol mL-1 min-1 ). Total bioavailability in obese mice is almost doubled that of control mice (1197 vs 679 nmol mL-1 min-1 ), while peaking times and elimination half-lives are delayed. Higher levels of RK and major metabolites are found in WAT of the obese than normal-weight animals.

CONCLUSIONS

RK is highly bioavailable, rapidly metabolized, and exhibits significantly different pharmacokinetic behaviors between obese and control mice. Lipid-rich tissues, especially WAT, can be a direct target of RK.

A Comprehensive Review on Preclinical Diabetic Models

BACKGROUND

Preclinical experimental models historically play a critical role in the exploration and characterization of disease pathophysiology. Further, these in-vivo and in-vitro preclinical experiments help in target identification, evaluation of novel therapeutic agents and validation of treatments.

INTRODUCTION

Diabetes mellitus (DM) is a multifaceted metabolic disorder of multidimensional aetiologies with the cardinal feature of chronic hyperglycemia. To avoid or minimize late complications of diabetes and related costs, primary prevention and early treatment are therefore necessary. Due to its chronic manifestations, new treatment strategies need to be developed, because of the limited effectiveness of the current therapies.

METHODS

The study included electronic databases such as Pubmed, Web of Science and Scopus. The datasets were searched for entries of studies up to June, 2018.

RESULTS

A large number of in-vivo and in-vitro models have been presented for evaluating the mechanism of anti-hyperglycaemic effect of drugs in hormone-, chemically-, pathogen-induced animal models of diabetes mellitus. The advantages and limitations of each model have also been addressed in this review.

CONCLUSION

This review encompasses the wide pathophysiological and molecular mechanisms associated with diabetes, particularly focusing on the challenges associated with the evaluation and predictive validation of these models as ideal animal models for preclinical assessments and discovering new drugs and therapeutic agents for translational application in humans. This review may further contribute to discover a novel drug to treat diabetes more efficaciously with minimum or no side effects. Furthermore, it also highlights ongoing research and considers the future perspectives in the field of diabetes.

Improving natural product research translation: From source to clinical trial

While great interest in health effects of natural product (NP) including dietary supplements and foods persists, promising preclinical NP research is not consistently translating into actionable clinical trial (CT) outcomes. Generally considered the gold standard for assessing safety and efficacy, CTs, especially phase III CTs, are costly and require rigorous planning to optimize the value of the information obtained. More effective bridging from NP research to CT was the goal of a September, 2018 transdisciplinary workshop. Participants emphasized that replicability and likelihood of successful translation depend on rigor in experimental design, interpretation, and reporting across the continuum of NP research. Discussions spanned good practices for NP characterization and quality control; use and interpretation of models (computational through in vivo) with strong clinical predictive validity; controls for experimental artefacts, especially for in vitro interrogation of bioactivity and mechanisms of action; rigorous assessment and interpretation of prior research; transparency in all reporting; and prioritization of research questions. Natural product clinical trials prioritized based on rigorous, convergent supporting data and current public health needs are most likely to be informative and ultimately affect public health. Thoughtful, coordinated implementation of these practices should enhance the knowledge gained from future NP research.

Anthocyanins and Their C6-C3-C6 Metabolites in Humans and Animals

Research on the bioavailability of anthocyanins has focused, historically, on the non-flavonoid (C6-Cn) products that arise from anthocyanins in vivo. However, this review focuses on the products of anthocyanins that still possess the flavonoid structure (C6-C3-C6). Described herein are aspects of the in vivo pool of C6-C3-C6 anthocyanin-derived intermediates. Properties related to molecular size, shape, and polarity conveyed by six major anthocyanidin structures are discussed. The presence of a glycoside or not, and a variety of possible phase 2 conjugates, gives rise to a chemically diverse pool of C6-C3-C6 intermediates. Chemical properties influence the in vivo stability of anthocyanin-derived products, as well as their suitability as a substrate for xenobiotic conjugation and transport, and their association with the biomatrix. The flavonoid structure is associated with bioactivity and the particular properties of these C6-C3-C6 products of anthocyanins determines their deposition in the body, which may influence in vivo processes and ultimately health outcomes.

Dietary polyphenols as a safe and novel intervention for modulating pain associated with intervertebral disc degeneration in an in-vivo rat model

Developing effective therapies for back pain associated with intervertebral disc (IVD) degeneration is a research priority since it is a major socioeconomic burden and current conservative and surgical treatments have limited success. Polyphenols are naturally occurring compounds in plant-derived foods and beverages, and evidence suggests dietary supplementation with select polyphenol preparations can modulate diverse neurological and painful disorders. This study tested whether supplementation with a select standardized Bioactive-Dietary-Polyphenol-Preparation (BDPP) may alleviate pain symptoms associated with IVD degeneration. Painful IVD degeneration was surgically induced in skeletally-mature rats by intradiscal saline injection into three consecutive lumbar IVDs. Injured rats were given normal or BDPP-supplemented drinking water. In-vivo hindpaw mechanical allodynia and IVD height were assessed weekly for 6 weeks following injury. Spinal column, dorsal-root-ganglion (DRG) and serum were collected at 1 and 6 weeks post-operative (post-op) for analyses of IVD-related mechanical and biological pathogenic processes. Dietary BDPP significantly alleviated the typical behavioral sensitivity associated with surgical procedures and IVD degeneration, but did not modulate IVD degeneration nor changes of pro-inflammatory cytokine levels in IVD. Gene expression analyses suggested BDPP might have an immunomodulatory effect in attenuating the expression of pro-inflammatory cytokines in DRGs. This study supports the idea that dietary supplementation with BDPP has potential to alleviate IVD degeneration-related pain, and further investigations are warranted to identify the mechanisms of action of dietary BDPP.

A Dietary Intervention of Bioactive Enriched Foods Aimed at Adults at Risk of Metabolic Syndrome: Protocol and Results from PATHWAY-27 Pilot Study

Around a quarter of the global adult population have metabolic syndrome (MetS) and therefore increased risk of cardiovascular mortality and diabetes. Docosahexaenoic acid, oat beta-glucan and grape anthocyanins have been shown to be effective in reducing MetS risk factors when administered as isolated compounds, but their effect when administered as bioactive-enriched foods has not been evaluated.

OBJECTIVE

The overall aim of the PATHWAY-27 project was to evaluate the effectiveness of bioactive-enriched food consumption on improving risk factors of MetS. A pilot study was conducted to assess which of five bioactive combinations provided within three different food matrices (bakery, dairy or egg) were the most effective in adult volunteers. The trial also evaluated the feasibility of production, consumer acceptability and gastrointestinal tolerance of the bioactive-enriched food.

METHOD

The study included three monocentric, parallel-arm, double-blind, randomised, dietary intervention trials without a placebo. Each recruiting centre tested the five bioactive combinations within a single food matrix.

RESULTS

The study was completed by 167 participants (74 male, 93 female). The results indicated that specific bioactive/matrix combinations have effects on serum triglyceride or HDL-cholesterol level without adverse effects.

CONCLUSION

The study evidenced that bioactive-enriched food offers a promising food-based strategy for MetS prevention, and highlighted the importance of conducting pilot studies.

Review of the Effect of Natural Compounds and Extracts on Neurodegeneration in Animal Models of Diabetes Mellitus

Diabetes mellitus is a chronic metabolic disease with a high prevalence in the Western population. It is characterized by pancreas failure to produce insulin, which involves high blood glucose levels. The two main forms of diabetes are type 1 and type 2 diabetes, which correspond with >85% of the cases. Diabetes shows several associated alterations including vascular dysfunction, neuropathies as well as central complications. Brain alterations in diabetes are widely studied; however, the mechanisms implicated have not been completely elucidated. Diabetic brain shows a wide profile of micro and macrostructural changes, such as neurovascular deterioration or neuroinflammation leading to neurodegeneration and progressive cognition dysfunction. Natural compounds (single isolated compounds and/or natural extracts) have been widely assessed in metabolic disorders and many of them have also shown antioxidant, antiinflamatory and neuroprotective properties at central level. This work reviews natural compounds with brain neuroprotective activities, taking into account several therapeutic targets: Inflammation and oxidative stress, vascular damage, neuronal loss or cognitive impairment. Altogether, a wide range of natural extracts and compounds contribute to limit neurodegeneration and cognitive dysfunction under diabetic state. Therefore, they could broaden therapeutic alternatives to reduce or slow down complications associated with diabetes at central level.

A critical review on grape polyphenols for neuroprotection: Strategies to enhance bioefficacy

The aging of populations worldwide is driving greater demands for dietary polyphenols which have been recognized as promising prophylactic and/or therapeutic agents in the context of neurodegeneration, and are ubiquitously present in plant-based diets. In particular, grape-derived products encompass a wide array of phenolic compounds purported with multiple health benefits including neuroprotective efficacy. Despite the increasing preclinical and clinical evidence demonstrating high potential of grape polyphenol (GPP)-rich botanicals in preventing and attenuating diverse neurodegenerative disorders, the limited bioavailability of GPPs, especially in the brain, generates questions as to their applications and effectiveness in neuroprotection. To address this issue, significant research efforts have been made to enhance oral bioavailability of GPPs via application of novel strategies. This review highlights some critical issues related to the bioavailability and neuroprotective efficacy of GPPs and GPP-rich botanicals. The representative bioavailability-enhancing strategies are critically reviewed to provide practical solutions for augmenting the bioefficacy of GPP-rich botanicals. Synergistic applications of encapsulation techniques (for physiochemical protection and bypassing xenobiotic metabolism) and dietary intervention strategies involving modulation of gut microbiota (for generating more bioavailable phenolic metabolites) appear promising, and may substantially enhance the bioefficacy, especially the neuroprotective efficacy, of orally consumed GPPs.

Anthocyanin Tissue Bioavailability in Animals: Possible Implications for Human Health. A Systematic Review

Anthocyanins (ACNs) are promising health-enhancing phenolic compounds. We focus on ACN animal tissue bioavailability to provide an evidentiary link between tissue ACNs and their associated health properties. We performed a systematic review of electronic libraries; 279 results were retrieved, and 13 publications met inclusion criteria. Extracted information included animal model employed, administration route, doses, analysis method, and ACN concentration values in tissues. Total ACN concentrations were detected in mice kidney (2.17 × 10⁵ pmol/g), liver (1.73 × 10⁵ pmol/g), heart (3.6 × 10³ pmol/g), and lung (1.16 × 10⁵ pmol/g); and in pig brain (6.08 × 10³ pmol/g). ACNs showed a predominance of parent ACNs in long-term experiments versus an ACN metabolite predominance in short-term experiments. ACNs detected in animal tissues, such as cyanidin-3-glucoside, suggest it may have an important role in human health. This information could be useful to determine proper ACN-intake biomarkers in biological samples in futures studies.

Neuroprotective Mechanisms of Resveratrol in Alzheimer's Disease: Role of SIRT1

Alzheimer's disease (AD) is a progressive and neurodegenerative disorder of the cortex and hippocampus, which eventually leads to cognitive impairment. Although the etiology of AD remains unclear, the presence of β-amyloid (Aβ) peptides in these learning and memory regions is a hallmark of AD. Therefore, the inhibition of Aβ peptide aggregation has been considered the primary therapeutic strategy for AD treatment. Many studies have shown that resveratrol has antioxidant, anti-inflammatory, and neuroprotective properties and can decrease the toxicity and aggregation of Aβ peptides in the hippocampus of AD patients, promote neurogenesis, and prevent hippocampal damage. In addition, the antioxidant activity of resveratrol plays an important role in neuronal differentiation through the activation of silent information regulator-1 (SIRT1). SIRT1 plays a vital role in the growth and differentiation of neurons and prevents the apoptotic death of these neurons by deacetylating and repressing p53 activity; however, the exact mechanisms remain unclear. Resveratrol also has anti-inflammatory effects as it suppresses M1 microglia activation, which is involved in the initiation of neurodegeneration, and promotes Th2 responses by increasing anti-inflammatory cytokines and SIRT1 expression. This review will focus on the antioxidant and anti-inflammatory neuroprotective effects of resveratrol, specifically on its role in SIRT1 and the association with AD pathophysiology.

Chemoprotective Effects of Dietary Grape Powder on UVB Radiation-Mediated Skin Carcinogenesis in SKH-1 Hairless Mice

Skin cancer is the most frequently diagnosed cancer in the United States, and solar UVR is an established causative factor for approximately 90% of these cases. Despite efforts aimed at UV protection, including use of sunscreen and clothing, annual cases of skin cancer continue to rise. Here, we report that dietary grape powder mitigates UVB-mediated skin carcinogenesis in an SKH-1 hairless mouse model. Using a UVB initiation-promotion protocol, whereby mice were exposed to 180 mJ/cm² UVB two times per week for 28 weeks, we determined the effects of a grape powder-fortified diet (3% or 5%) on skin carcinogenesis. Grape powder consumption at both doses resulted in marked inhibition in tumor incidence, as well as a delay in onset of tumorigenesis. Molecular analyses of skin and tumor tissue showed that grape powder-mediated protective response against UVB-induced skin cancer was accompanied by enhanced DNA damage repair, reduced proliferation, increased apoptosis, and modulations in several oxidative stress markers specifically related to inhibition of oxidative stress and increased reactive oxygen species metabolism. NRF2, an activator of cellular antioxidant response, was decreased by grape powder feeding, suggesting a supportive role in tumor cell survival. Overall, our study suggested that dietary grape, containing several antioxidants in natural amalgamation, may protect against UVB-mediated skin carcinogenesis.