Cocoa flavanols show beneficial effects in cultured pancreatic beta cells and liver cells to prevent the onset of type 2 diabetes

Bioavailable Microbial Metabolites of Flavanols Demonstrate Highly Individualized Bioactivity on In Vitro β-Cell Functions Critical for Metabolic Health

Dietary flavanols are known for disease preventative properties but are often poorly absorbed. Gut microbiome flavanol metabolites are more bioavailable and may exert protective activities. Using metabolite mixtures extracted from the urine of rats supplemented with flavanols and treated with or without antibiotics, we investigated their effects on INS-1 832/13 β-cell glucose stimulated insulin secretion (GSIS) capacity. We measured insulin secretion under non-stimulatory (low) and stimulatory (high) glucose levels, insulin secretion fold induction, and total insulin content. We conducted treatment-level comparisons, individual-level dose responses, and a responder vs. non-responder predictive analysis of metabolite composition. While the first two analyses did not elucidate treatment effects, metabolites from 9 of the 28 animals demonstrated significant dose responses, regardless of treatment. Differentiation of responders vs. non-responder revealed that levels of native flavanols and valerolactones approached significance for predicting enhanced GSIS, regardless of treatment. Although treatment-level patterns were not discernable, we conclude that the high inter-individual variability shows that metabolite bioactivity on GSIS capacity is less related to flavanol supplementation or antibiotic treatment and may be more associated with the unique microbiome or metabolome of each animal. These findings suggest flavanol metabolite activities are individualized and point to the need for personalized nutrition practices.

Cocoa seeds and chocolate products interaction with gut microbiota; mining microbial and functional biomarkers from mechanistic studies, clinical trials and 16S rRNA amplicon sequencing

In recent years, gut microbiome has evolved as a focal point of interest with growing recognition that a well-balanced gut microbiota is highly relevant to an individual's health status. The present review provides a mechanistic insight on the effects of cocoa chemicals on the gut microbiome and further reveals in silico biomarkers, taxonomic and functional features that distinguish gut microbiome of cocoa consumers and controls by using 16S rRNA gene sequencing data. The polyphenols in cocoa can change the gut microbiota either by inhibiting the growth of pathogenic bacteria in the gut such as Clostridium perfringens or by increasing the growth of beneficial microbiota in the gut such as Lactobacillus and Bifidobacterium. This paper demonstrates the holistic effect of gut microbiota on cocoa chemicals and how it impacts human health. We present herein the first comprehensive review and analysis of how raw and roasted cocoa and its products can specifically influence gut homeostasis, and likewise, how microbiota metabolizes cocoa chemicals. In addition to that, our 16S rRNA amplicon sequencing analysis revealed that the flavone and flavonols metabolism, aminobenzoate degradation and fatty acid elongation pathways represent the three most important signatures of microbial functions associated with cocoa consumption.

Cocoa extract exerts sex-specific anti-diabetic effects in an aggressive type-2 diabetes model: A pilot study

Type 2 diabetes (T2D) is characterized by hyperglycemia and insulin resistance. Cocoa may slow T2D development and progression. This study employed male and female BTBR.Cg-Lep^ob/ob/WiscJ (ob/ob) and wild type (WT) controls to assess the potential for cocoa to ameliorate progressive T2D and compare responses between sexes. Mice received diet without (WT, ob/ob) or with cocoa extract (ob/ob + c) for 10 weeks. Acute cocoa reduced fasting hyperglycemia in females, but not males, after 2 weeks. Chronic cocoa supplementation (6-10 weeks) ameliorated hyperinsulinemia in males and worsened hyperlipidemia and hyperinsulinemia in females, yet also preserved and enhanced beta cell survival in females. The underlying mechanisms of these differences warrant further study. If sex differences are apparent in subsequent preclinical studies, clinical studies will be warranted to establish whether these differences are relevant in humans. Sex differences may need to be considered when designing human dietary interventions for T2D.

Traceability of polyphenols in cocoa during the postharvest and industrialization processes and their biological antioxidant potential

Noncommunicable diseases, the leading cause of mortality around the world, are responsible for approximately 75% of premature adult deaths (ages 30-69). To tackle this issue, a healthy diet based on functional foods, including cocoa and its derivatives, has been increasingly promoted. The polyphenols present in cocoa have been of interest due to their antioxidant potential and their possible protective role in the context of noncommunicable diseases, such as diabetes and cardiovascular conditions. However, during cocoa postharvest and industrialization, the concentration of these bioactive compounds is reduced, possibly affecting their health-promoting properties. Therefore, this paper reviews in the literature in this field to find the total polyphenol content in cocoa during the postharvest and industrialization processes in order to define concentration ranges as a reference point for future research. In addition, it discusses in vitro and in vivo studies into the biological antioxidant potential of cocoa and its derivatives. This review covers publications in indexed databases from 2010 to 2020, their data were processed and presented here using box plots. As a result, we identified the concentration ranges of polyphenols depending on the type of matrix, treatment and country, as well as their relationship with the main bioactive compounds present in cocoa that are associated with their possible antioxidant biological potential and health-related benefits.

Pre-Treatment with Grape Seed Extract Reduces Inflammatory Response and Oxidative Stress Induced by Helicobacter pylori Infection in Human Gastric Epithelial Cells

Helicobacter pylori (H. pylori) is a pathogenic bacteria identified as a potential risk factor for gastritis, gastric ulcers and gastric cancer. During the stomach colonization, H. pylori triggers a strong inflammatory response and subsequent oxidative stress, which are associated with tissue damage. For this reason, it is of particular interest to develop alternative natural tools that enable modulation of the associated damaging immune response. With this purpose, we obtained grape seed extract (GSE) from sweet (not fermented) food grade seeds. The aim of our study was to investigate the effect of GSE and its two enriched procyanidins fractions (OPC and PPC) on the inflammatory process and oxidative stress produced by different H. pylori strains in human gastric epithelial cells (AGS). Anti-inflammatory activity was evaluated by measuring the level of interleukin-8 (IL-8) secretion. IL-8 production was significantly reduced in H. pylori-infected human gastric epithelial cells pre-treated with GSE or its enriched fractions when compared with non-pre-treated infected cells (from 21.6% to 87.8%). Pre-treatment with GSE or its fractions significantly decreased intracellular reactive oxygen species (ROS) production in AGS cells after infection, depending on the H. pylori strain. Our results also showed that GSE and its fractions demonstrate antibacterial activity against all strains of H. pylori used in the study. This work demonstrates the effectiveness of GSE enriched in procyanidins against the main events associated with H. pylori infection.

Flavanols and triterpenoids from Myrianthus arboreus ameliorate hyperglycaemia in streptozotocin-induced diabetic rats possibly via glucose uptake enhancement and α-amylase inhibition

Myrianthus arboreus is use traditionally as an antidiabetic agent in Ghana. We reported the in vivo antidiabetic activity of its 70 % ethanol stem bark extract (MAB) which we found to be strongly concentrated in its EtOAc fraction using glucose uptake and enzyme inhibitory assays. The present study sought to investigate the in vivo hypoglycaemic and anti-hyperlipidaemic activity of this ethyl acetate fraction of MAB (MAB-EtOAc, 50 and 100 mg/kg) in streptozotocin (STZ)-induced diabetic rats for 21 days, isolate and evaluate the bioactive constituents responsible for the antidiabetic activity. In silico pharmacokinetic and toxicity properties of the most active compound was also determined. MAB-EtOAc significantly (p < 0.001) reduced the blood glucose levels while normalizing considerably the altered serum lipid parameters of the diabetic rats which was comparable to glibenclamide (5 mg/kg). Chemical investigation of MAB-EtOAc led to the isolation of seven known compounds including three flavanols which are reported for the first time in the plant: epicatechin (1), epigallocatechin (2), dulcisflavan (3), euscaphic acid (4), tormentic acid (5), sitosterol-3-O-β-d-glucopyranoside (6) and arjunolic acid (7). The compounds markedly inhibited the action of α-amylase and, except for 4 and 6, which stimulated considerably glucose uptake in C2C12 cells. Compounds 2, 3, 5, 6 and 7 which were further evaluated in STZ-induced diabetic rats demonstrated hypoglycaemic and anti-hyperlipidaemic activities which, however, were not comparable with MAB-EtOAc. Compound 3, the most active compound was predicted to be non-toxic, non-mutagenic, has reasonable oral bioavailability and a decent substrate for further drug development. The findings of this study show that the isolated compounds may contribute to the antidiabetic activity of M. arboreus and could serve as marker compounds for the quality control of herbal medicines that would be made from the plant.

Modulation of Antibacterial, Antioxidant, and Anti-Inflammatory Properties by Drying of Prunus domestica L. Plum Juice Extracts

The consumption of plums in a fresh form is seasonal, therefore the transformation of plum juice extracts into powdered form is a good alternative for its longer availability throughout the year. The drying process can moderate the physical and chemical properties of the plum extracts, thus, this study examined the changes in biological activity, i.e., antibacterial, antioxidant, and anti-inflammatory properties moderated by freeze, vacuum, and spray drying. It was suggested that the drying processes and the applied parameters might moderate the content of polyphenolic compounds in the powders, which influence the different levels of growth inhibition against the foodborne pathogens (17% to 58% of inhibition), demonstrating a strain-dependent effect. These powders could also induce cellular protection against oxidative stress by preventing intracellular reactive oxygen species (ROS) accumulation (23% to 37% of reduction), but the level of antioxidant capacity may be determined by the conditions applied during the drying process. Moreover, plum extract powders exhibited a greater anti-inflammatory capacity (24% to 39% of inhibition), which would be influenced both, by the type of treatment used and by the temperature used in each treatment. The results demonstrate that the selection of the drying method can be an effective tool for modulating the composition, physical, and bioactive properties of plum extracts powders.

Anti-inflammatory effects of grape seed procyanidin B2 on a diabetic pancreas

The prevalence of type 2 diabetes mellitus (T2DM) has increased considerably in recent years, highlighting the importance of developing new therapeutic strategies. Insulin-resistance and gradual dysfunction of pancreatic islets are the mainstay in the progression of T2DM. Therefore, preserving the function of the pancreas may lead to new prospective approaches. Our previous studies suggested that grape seed procyanidin B2 (GSPB2), a natural polyphenol product, exhibited protective effects on diabetic vasculopathy. However, effects of GSPB2 on a diabetic pancreas remain unknown. In this study, we provided strong evidence that GSPB2 exerted protective effects on a diabetic pancreas. GSPB2 attenuated the elevated body weights, food intake and advanced glycation end-product (AGE) levels in db/db mice (p < 0.05), though it had no significant effect on glucose levels. The increased islet sizes, insulin levels, as well as HOMA-IR were also improved by GSPB2 treatment in db/db mice (p < 0.05). Milk fat globule epidermal growth factor-8 (MFG-E8), an estimated target of GSPB2 in our previous studies, was up-regulated in pancreatic tissues whereas GSPB2 treatment down-regulated the protein level (p < 0.05). Since MFG-E8 is highly involved in inflammation, we further investigate pro-inflammatory cytokines interleukin-1β (IL-1β) and NLRP3 levels. We found that levels of IL-1β and NLRP3 increased in a diabetic pancreas while GSPB2 treatment notably attenuated these alterations (p < 0.05). In conclusion, our results suggest that inflammation is involved in the damage of a diabetic pancreas and GSPB2 provides protective effects at least in part through anti-inflammation.

A protective effect of anthocyanins and xanthophylls on UVB-induced damage in retinal pigment epithelial cells

Cyanidin-3-glucoside and zeaxanthin, alone or in combination, protect against UVB-induced retinal cells damage throw redox and MAPK activation regulation.