Determination of Catechin and Epicatechin Content in Chocolates by High-Performance Liquid Chromatography

Topical Antioxidant Cocoa Polyphenol Skin Penetration

BACKGROUND

Cocoa powder derived from the Theobroma cacao plant is rich in polyphenols, such as catechin and epicatechin. These polyphenols are strong antioxidants when consumed orally; however, their ability to enter the stratum corneum following the topical application has never been demonstrated.

OBJECTIVE

The objective of this study was to demonstrate the deposition of catechin and epicatechin in the stratum corneum following the topical application of 6% aqueous cocoa powder 1 and 2 h after application.

METHODS

Five healthy female subjects aged 25-60 years were enrolled. A 6% aqueous cocoa powder solution was prepared and applied to two randomized designated spots on the left forearm. 2 cc of the solution was applied under a ¼-inch gauze square covered with plastic wrap and held in place with a Coban dressing. The 15 d-squame 7/8-inch circular tape strips were applied to the predetermined area on the forearm 1 h and 2 h after application of the 6% cocoa powder solution. The tape strips were immediately placed in a -80°C freezer for storage until extraction in preparation for LC-MS evaluation for catechin and epicatechin levels.

RESULTS

More catechin and epicatechin were detected at 2 h than 1 h for both compounds, although the difference was not statistically significant. Higher epicatechin levels than catechin levels were detected from the cocoa powder at both time points. This is consistent with published data from food-grade cocoa powder.

SUMMARY

It is detected that 6% aqueous cocoa powder delivers the antioxidants catechin and epicatechin to the stratum corneum 1 h and 2 h after topical application.

Cocoa flavanols, Nrf2 activation, and oxidative stress in peripheral artery disease: mechanistic findings in muscle based on outcomes from a randomized trial

The pathophysiology of muscle damage in peripheral artery disease (PAD) includes increased oxidant production and impaired antioxidant defenses. Epicatechin (EPI), a naturally occurring flavanol, has antioxidant properties that may mediate the beneficial effects of natural products such as cocoa. In a phase II randomized trial, a cocoa-flavanol-rich beverage significantly improved walking performance compared with a placebo in people with PAD. In the present work, the molecular mechanisms underlying the therapeutic effect of cocoa flavanols were investigated by analyzing baseline and follow-up muscle biopsies from participants. Increases in nuclear factor erythroid 2-related factor 2 (Nrf2) target antioxidants heme oxygenase-1 (HO-1) and NAD(P)H dehydrogenase [quinone] 1 (NQO1) in the cocoa group were significantly associated with reduced accumulation of central nuclei, a myopathy indicator, in type II muscle fibers (P = 0.017 and P = 0.023, respectively). Protein levels of the mitochondrial respiratory complex III subunit, cytochrome b-c1 complex subunit 2 (UQCRC2), were significantly higher in the cocoa group than in the placebo group (P = 0.032), and increases in UQCRC2 were significantly associated with increased levels of Nrf2 target antioxidants HO-1 and NQO1 (P = 0.001 and P = 0.035, respectively). Exposure of non-PAD human myotubes to ex vivo serum from patients with PAD reduced Nrf2 phosphorylation, an indicator of activation, increased hydrogen peroxide production and oxidative stress, and reduced mitochondrial respiration. Treatment of myotubes with EPI in the presence of serum from patients with PAD increased Nrf2 phosphorylation and protected against PAD serum-induced oxidative stress and mitochondrial dysfunction. Overall, these findings suggest that cocoa flavanols may enhance antioxidant capacity in PAD via Nrf2 activation.NEW & NOTEWORTHY The current study supports the hypothesis that in people with PAD, cocoa flavanols activate Nrf2, thereby increasing antioxidant protein levels, protecting against skeletal muscle damage, and increasing mitochondrial protein abundance. These results suggest that Nrf2 activation may be an important therapeutic target for improving walking performance in people with PAD.

Fluorescent dual-mode sensor for the determination of graphene oxide and catechin in environmental or food field

The novel fluorescent sensor is proposed in this work based on the competitive interactions between the known bioactive compounds, riboflavin and catechin, which act as guests, and graphene oxide (GO) material that acts as host. Specifically, this proposal is based on an indicator displacement assay which allows the detection of GO and catechin (fluorescence quenching of riboflavin signal by GO and increase in fluorescence by catechin on the GO-riboflavin system). Three GO structures with different lateral dimensions and thickness were synthesized and tested, being able to be the three differentiated depending on the attenuation capacity of the fluorescent signal that each one possesses. The environmental analytical control of GO is more and more important, being this method sensitive and selective in the presence of other potential interferent substances. On the other hand, the other sensing capacity of the sensor also allows the determination of catechin in food samples based on the formation of riboflavin-GO complex. It is a rapid, simple and non-expensive procedure. Thus, the same 2D nanomaterial (GO) is seen to play a double role in this sensing strategy (analyte and analytical tool for the determination of another compound).

Application of the herbal chemical marker ranking system (Herb MaRS) to the standardization of herbal raw materials: a case study

INTRODUCTION

Phytochemical standardization of herbal materials involves establishing consistent levels of one or more active ingredients or markers. It ensures the authenticity and quality of herbal materials, extracts, and their products. This research aimed to apply the herbal chemical marker ranking system (Herb MaRS) originally proposed for quality assurance of complex herbal products to establish markers for controlling the quality of herbal raw materials.

METHODS

The assessment of compounds for suitability as markers was based on the Herb MaRS, with minor modifications as follows: for more objective scoring, evidence of biological activity of the potential marker compound(s) was determined at three levels based on the number of symptoms of the disease condition a compound can treat or alleviate: (i) one symptom (1 point), two symptoms (2 points), and 3 or more symptoms (3 points). The reported concentrations of the compounds were also scored as follows: concentration not determined (0 points), concentration ≥ 5 ppm (1 point), concentration ≥ 50 ppm (2 points) and availability of analytical standards (1 point). Finally, the compounds were scored for the availability of an analytical method (1 point). The compounds were scored from 0 to 8, where 8 indicated the most suitable chemical marker.

RESULTS

The selected markers were as follows: aromadendrine, α-terpineol, globulol, and 1,8-cineol (in Eucalyptus globulus Labill. ); aloin, aloe emodin, acemannan (in Aloe barbadensis (L.) Burm.f. ), lupeol, lupenone, betulinic acid, betulin, and catechin (in Albizia coriaria Oliv.); mangiferin, catechin, quercetin, and gallic acid (in Mangifera indica L.); polygodial (in Warburgia ugandensis Sprague); azadirachtin, nimbin, nimbidin (in Azadirachta indica A. Juss. ); and 6,8,10-gingerols, and 6-shogaol (in Zingiber officinalis Roscoe).

CONCLUSIONS

Herb MaRS can be efficiently applied to select marker compounds for quality control of herbal materials. However, for herbs whose phytochemicals have not been sufficiently researched, it is difficult to establish evidence of activity, and there are no analytical standards and/or methods; this is the case for plants exclusively used in Africa. The markers identified should be incorporated into chromatographic fingerprints, their quantitative methods developed, and evaluated for applicability at the various stages of the production chain of herbal medicines; then, they can be included in future local plant monographs. There is also a need to build local capacity to isolate marker compounds, particularly those that are not sold by current vendors.

Release of phenolic compounds from fermented cocoa powder during fast heating in a novel hot plate reactor

This article studies the release of phenolic compounds during cocoa heating under vacuum, N₂, and air atmospheres, and proposes fast heating (60 °C • s^-1) as a methodology that allows the release of polyphenols from fermented cocoa powder. We aim to demonstrate that gas phase transport is not the only mechanism to extract compounds of interest and that convective-type mechanisms can facilitate the process by reducing their degradation. The oxidation and transport phenomena were evaluated both in the extracted fluid and in the solid sample during the heating process. Polyphenols transport phenomena were assessed based on the fluid (chemical condensate compounds) that was collected cold with an organic solvent (methanol) in a hot plate reactor. Out of all the polyphenolic compounds present in cocoa powder, we assessed specifically the release of catechin and epicatechin. We found that high heating rates combined with vacuum or N₂ favor the ejection of liquids; then, it is possible to extract compounds such as catechin-which is dissolved/entrained and transported in the ejected liquids-and avoid degradation phenomena.

Evaluation of in vitro whey protein digestibility in a protein-catechins model system mimicking milk chocolate: Interaction with flavonoids does not hinder protein bioaccessibility

Flavonoids are largely present in plant food such as cocoa and derived products. These compounds can interact with proteins inherently contained in the food matrix and/or the proteolytic enzymes involved in gastrointestinal digestion. The flavonoid/protein interaction might hamper protein bioaccessibility and digestibility, affecting the nutritional quality. However, information on the digestion fate of proteins in food matrices containing both proteins and flavonoids is limited. The aim of this work was to evaluate the interaction between proteins and flavonoids and verify the potential effects of this interaction on protein digestibility. Taking milk chocolate as model, first a simple whey proteins/catechins mixed system was evaluated, and then the effects on digestibility were also verified in a real sample of commercial milk chocolate. The effects of the catechins/whey proteins interaction in the model system were evaluated by optical and chiro-optical spectroscopy, outlining a slight protein structure modification upon interaction with catechins. The digestibility of the protein fraction both in the model system, with and without catechins, and also in milk chocolate, was then determined by the application of INFOGEST in vitro digestion method: the bioaccessibility was evaluated in terms of protein hydrolysis and protein solubilisation, and major peptides generated by the digestion were also determined by LC/HR-MS. Despite the slight interaction with proteins, flavonoids were found to not hinder nor modify protein solubilization, protein hydrolysis and peptide profile by digestive enzymes. Also protein digestibility in milk chocolate, evaluated by SDS-PAGE, was found to be complete. The present data clearly indicate that the interaction of the proteins with the flavonoids present in the cocoa matrix does not to affect protein bioaccessibility during digestion.

The Study of Mineral Elements Participation in Brewing Products Foam Structure Formation

The article is devoted to the study of the metal ion’s role in the formation of the foam colloidal structure. The nitrogenous compounds prominent role as structuring compounds of the colloidal film on the carbon dioxide bubbles surface is noted. Based on the calculation of the correlation strength between beer samples organic compounds obtained based on light and dark malts, as well as barley and corn as unmalted raw materials, the effect of Ca, Mg, Mn, Co and Na mineral ions on the foam structure was evaluated. It was shown that Ca, Mg, Mn, Na, Co ions take part in the foam structure formation in conjunction with the grain raw materials thiol nitrogen, and Ca, Mg, Mn ions in conjunction with catechins of both grain and hop raw materials. High correlation coefficients between foam resistance and all ions (r-0.991÷0.998), foam resistance, catechins and Co ions (r 0.991), as well as foam resistance and Ca and Mg ions (r -0.987) ensure the elasticity of the foam structure colloidal film.

UPLC-QToF-MS based fingerprinting of polyphenolic metabolites in the bark extract of Boehmeria rugulosa Wedd

Boehmeria rugulosa Wedd. is an evergreen tree of Urticaceae family. Its bark has been extensively used in ethno-medicinal system for various ailments such as bone fracture, sprain, snakebite, and wound healing. Phyto-metabolites, which are considered as the principle components for biological activities, have been least explored for this plant. The present work investigated metabolite profiling of the stem bark of B. rugulosa in water extract using Ultra Performance Liquid Chromatography Quadrupole Time of Flight Mass Spectrometry (UPLC-QToF-MS) technique coupled with the UNIFI platform. We identified, for the first time, 20 polyphenolic metabolites belonging to seven groups: caffeoylquinic acids, coumaroylquinic acids, flavan-3-ols, oligomeric flavonoids, caffeic acid derivatives, coumaric acid derivative, and flavone glycoside in the B. rugulosa extract. UNIFI informatics-coupled UPLC-QToF-MS platform aids in the quick identification and fragmentation pattern of metabolites, with higher degree of reproducibility. The present study provides a chemical and therapeutic basis for further exploration of B. rugulosa as a valuable source of phytochemicals that could be instrumental in deciphering its ethno-medicinal utility for various human diseases.

Developing colloidal structure of beer by grain organic compounds

The present article introduces the problem of determining the general structure of beer as a complex system of related biomolecules. The objective was to establish the correlation of various quantities of organic compounds in beer formulation. The research featured samples of filtered pasteurized beer obtained from a retail chain shop in Moscow (Russia). The experiment relied on standard research methods, including instrumental methods of analysis, e.g., high-performance liquid chromatography (HPLC). The obtained experimental data underwent a statistical analysis using the Statistica software (StatSoft, 2016). The research established the correlation between the type of grain (barley or wheat malt) and the content of organic compounds, e.g., β-glucan, polyphenols, soluble nitrogen, etc. The research also revealed some patterns in the distribution of proteins, which served as a framework for the system of organic compounds. The distribution of thiol proteins proved to depend on the dissolution degree of the grain and was different in barley light, barley dark, and wheat malt samples. The fraction distribution of β-glucan depended on the color of the malt. In light beer samples, it concentrated in high- and medium-molecular fractions of nitrogenous substances, in dark beer – in low-molecular fractions (≤ 63%). Initial wort density and alcohol content affected the amount of catechins and total polyphenols. Nitrogenous compounds depended on the color, initial extract, and alcohol content. The nitrogenous structure and other organic compounds of beer proved to depend on protein substances. The research also revealed a number of factors that affected the fraction distribution of biomolecules in different beer sorts.

Interaction between Chocolate Polyphenols and Encapsulated Probiotics during In Vitro Digestion and Colonic Fermentation

This study evaluated the interaction between probiotics and polyphenols in chocolates (45% and 70% cocoa) fortified with encapsulated probiotics. Cocoa powder was used as the main encapsulation component in a Na-alginate plus fructooligosaccharides formulation. Probiotic-chocolates (PCh) were produced by adding 1% encapsulated probiotics to the final mixture. The chocolate samples were subjected to in vitro gastrointestinal digestion and colonic fermentation. The data revealed that the most bioaccessible polyphenols in both formulations of PCh containing 45% and 70% cocoa were released in the gastric digested supernatant. The bioaccessible polyphenols from PCh with 70% cocoa reached 83.22–92.33% and 8.08–15.14% during gastrointestinal digestion and colonic fermentation, respectively. Furthermore, the polyphenols with higher bioaccessibility during colonic fermentation of both PChs developed with the CA1 formulation (cocoa powder 10%, Na-alginate 1% and fructooligosaccharides 2%) were detected in the presence of Streptococcus thermophilus and Lactobacillus sanfranciscensis. The results showed that PCh with specific probiotics favored the bioconversion of a specific polyphenol. For example, chocolate fortified with Lacticaseibacillus casei released larger quantities of epicatechin and procyanidin B1, while Lactiplantibacillus plantarum released more catechin and procyanidin B1 for Lacticaseibacillus rhamnosus LGG. Overall, the study findings concluded that chocolate polyphenols could be utilized by probiotics for their metabolism and modulating the gut, which improved the chocolates’ functionality.

Platelet Activation Favours NOX2-Mediated Muscle Damage in Elite Athletes: The Role of Cocoa-Derived Polyphenols

Mechanisms of exercise-induced muscle injury with etiopathogenesis and its consequences have been described; however, the impact of different intensities of exercise on the mechanisms of muscular injury development is not well understood. The aim of this study was to exploit the relationship between platelet activation, oxidative stress and muscular injuries induced by physical exercise in elite football players compared to amateur athletes. Oxidant/antioxidant status, platelet activation and markers of muscle damage were evaluated in 23 elite football players and 23 amateur athletes. Compared to amateurs, elite football players showed lower antioxidant capacity and higher oxidative stress paralleled by increased platelet activation and muscle damage markers. Simple linear regression analysis showed that sNOX2-dp and H₂O₂, sCD40L and PDGF-bb were associated with a significant increase in muscle damage biomarkers. In vitro studies also showed that plasma obtained from elite athletes increased oxidative stress and muscle damage in human skeletal muscle myoblasts cell line compared to amateurs’ plasma, an effect blunted by the NOX2 inhibitor or by the cell treatment with cocoa-derived polyphenols. These results indicate that platelet activation increased muscular injuries induced by oxidative stress. Moreover, NOX2 inhibition and polyphenol extracts treatment positively modulates redox status and reduce exercise-induced muscular injury.

The Influence of Hop Phenolic Compounds on Dry Hopping Beer Quality

Background: The article considers the phenolic hop compounds’ effect on the quality indicators of finished beer. The topic under consideration is relevant since it touches on the beer matrix colloidal stability when compounds with potential destabilizing activity are introduced into it from the outside. Methods: The industrial beer samples’ quality was assessed by industry-accepted methods and using instrumental analysis methods (high-performance liquid chromatography methods—HPLC). The obtained statistical data were processed by the Statistics program (Microsoft Corporation, Redmond, WA, USA, 2006). Results: The study made it possible to make assumptions about the functional dependence of the iso-α-bitter resins and isoxanthohumol content in beer samples. Mathematical analysis indicate interactions between protein molecules and different malted grain and hop compounds are involved in beer structure, in contrast to dry hopped beer, where iso-a-bitter resins, protein, and coloring compounds were significant, with a lower coefficient of determination. The main role of rutin in the descriptor hop bitterness has been established in kettle beer hopping technology, and catechin in dry beer hopping technology, respectively. The important role of soluble nitrogen and β-glucan dextrins in the perception of sensory descriptors of various technologies’ beers, as well as phenolic compounds in relation to the formation of bitterness and astringency of beer of classical technology and cold hopping, has been shown. Conclusions: The obtained mathematical relationships allow predicting the resulting beer quality and also make it possible to create the desired flavor profiles.

Repeated exposure to epigallocatechin gallate solution or water alters bitterness intensity and salivary protein profile

Polyphenols, bitter and astringent compounds present in many healthy foods, induce varied sensory responses across individuals. These differences in liking and flavor intensity may be attributable, in part, to differences in saliva. In the current study, we tested the effect of repeated consumption of a bitter polyphenol (epigallocatechin gallate, EGCG) solution on perceived bitterness intensity and salivary protein composition. We hypothesized exposure to EGCG would cause an increase in concentrations of salivary proteins that inhibit bitterness of polyphenols. We also hypothesized that participants with higher habitual polyphenol, specifically the flavanols, intake would experience less bitterness from EGCG solutions than those with low habitual intake, and that the high flavanol consumers would be more resistant to salivary alterations. We also tested whether bovine milk casein, a food analog for salivary proteins that may suppress bitterness, would decrease bitterness intensity of the EGCG solution and mitigate effects of the intervention. Participants (N = 37) in our crossover intervention adhered to two-week periods of daily bitter (EGCG) or control (water) solution consumption. Bitterness intensity ratings and citric acid-stimulated saliva were collected at baseline and after each exposure period. Results indicate that bitterness intensity of the EGCG solution decreased after polyphenol (bitter EGCG) exposure compared to control (water) exposure. Casein addition also decreased bitterness intensity of the EGCG solution. While there was not a significant overall main effect of baseline flavanol intake on solution bitterness, there was an interaction between intervention week and baseline flavanol intake. Surprisingly, the higher flavanol intake group rated EGCG solutions as more bitter than the low and medium intake groups. Of proteins relevant to taste perception, several cystatins changed in saliva in response to the intervention. Interestingly, most of these protein alterations occurred more robustly after the control (water) exposure rather than the bitter (EGCG) exposure, suggesting that additional factors not quantified in this work may influence salivary proteins. Thus, we confirm in this study that exposure to bitterness suppresses ratings of bitterness over time, but more work needs to establish the causal factors of how diet influences salivary proteins.

Protective effect of (+)-catechin against lipopolysaccharide-induced inflammatory response in RAW 264.7 cells through downregulation of NF-κB and p38 MAPK

Catechin, a flavonol belonging to the flavonoid group of polyphenols is present in many plant foods. The present study was done to evaluate the effect of catechin on various inflammatory mediators using lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. The effect of catechin on total cyclooxygenase (COX) activity, 5-lipoxygenase (5-LOX), myeloperoxidase, nitrite and inducible nitric oxide synthase (iNOS) level, secretion of tumor necrosis factor-α (TNF-α) and interleukin-10 (IL-10) were assessed in LPS-stimulated RAW 264.7 cells. The expression of COX-2, iNOS, TNF-α, nuclear factor-ĸB (NF-κB) and p38 mitogen-activated protein kinase (MAPK) genes were also investigated. The effect was further analyzed using human PBMCs by assessing the level of TNF-α and IL-10. The study demonstrated that the inflammatory mediators such as COX, 5-LOX, nitrite, iNOS, and TNF-α were significantly inhibited by catechin in a concentration-dependent manner whereas IL-10 production was up-regulated in RAW 264.7 cells. Moreover, catechin down-regulated the mRNA level expression of COX-2, iNOS, TNF-α, NF-κB and p38 MAPK. The current study ratifies the beneficial effect of catechin as a dietary component in plant foods to provide protection against inflammatory diseases.

Comparison of the Effects of Conching Parameters on the Contents of Three Dominant Flavan3-ols, Rheological Properties and Sensory Quality in Chocolate Milk Mass Based on Liquor from Unroasted Cocoa Beans

The content of polyphenols in chocolate depends on many factors related to the properties of raw material and manufacturing parameters. The trend toward developing chocolates made from unroasted cocoa beans encourages research in this area. In addition, modern customers attach great importance to how the food they consume benefits their bodies. One such benefit that consumers value is the preservation of natural antioxidant compounds in food products (e.g., polyphenols). Therefore, in our study we attempted to determine the relationship between variable parameters at the conching stage (i.e., temperature and time of) and the content of dominant polyphenols (i.e.,catechins, epicatechins, and procyanidin B2) in chocolate milk mass (CMM) obtained from unroasted cocoa beans. Increasing the conching temperature from 50 to 60 °C decreased the content of three basic flavan-3-ols. The highest number of these compounds was determined when the process was carried out at 50 °C. However, the time that caused the least degradation of these compounds differed. For catechin, it was 2 h; for epicatechin it was 1 h; and for procyanidin it was 3 h. The influence of both the temperature and conching time on the rheological properties of chocolate milk mass was demonstrated. At 50 °C, the viscosity and the yield stress of the conched mass showed its highest value.

From untargeted metabolomics to the multiple reaction monitoring-based quantification of polyphenols in chocolates from different geographical areas

Plants, including cocoa bean, are the main source of metabolites with multiple biological functions. Polyphenol extracts are widely used as a nutraceutical supplement for their well-known health-promoting role. In this paper, a preliminary untargeted metabolic screening was carried out by matrix-assisted laser desorption/ionization (MALDI)-time of flight (TOF)/TOF on a pool of chocolate samples made by cocoa beans of different geographical areas. Then, a targeted approach was developed for polyphenol quantification by an optimized Liquid chromatography (LC)-tandem mass spectrometry (MS/MS) method multiple reaction monitoring (MRM) ion mode. Detection limit of polyphenol standard ranged between 1 and 25 pg/μl with variation coefficient lower than 15%. External calibration curves were used for quantification of polyphenols in 18 samples. Fifty polyphenols were detected in a single LC-MRM/MS run and quantified by monitoring almost 90 transitions in a 5-minute run. The polyphenols content of different cocoa beans from several countries was finally compared by principal component analysis (PCA) statistical analysis suggesting that the chocolate made by Ecuador cocoa beans showed the highest level of polyphenols.

Mass Spectrometry and 1H-NMR Study of Schinopsis lorentzii (Quebracho) Tannins as a Source of Hypoglycemic and Antioxidant Principles

The ethyl acetate extract of the commercial tannin Tan’Activ QS-SOL (from Schinopsis lorentzii wood), employed for the production of red wine, was subjected to chromatography on Sephadex LH-20, providing nine fractions (A-1–A-9), which were estimated for total phenols content (GAE), antioxidant activity (DPPH, ORAC), and hypoglycemic activity (α-glucosidase and α-amylase inhibition). All the fractions were analyzed by means of HPLC/ESI-MS/MS and ¹H-NMR to identify the principal active constituents. Fractions A-1 and A-3 showed the highest antioxidant activity and gallic acid (1), pyrogallol (3), eriodictyol (6), catechin (12), and taxifolin (30) were identified as the major constituents. The highest α-glucosidase and α-amylase inhibitory activity was observed in fractions A-7–A-9 containing condensed (9′, 15, 18, 19, 23, and 27) hydrolysable tannins (13 and 32) as well as esters of quinic acid with different units of gallic acid (5, 11, 11′, 14, and 22). This last class of gallic acid esters are here reported for the first time as α-glucosidase and α-amylase inhibitors.

Mitochondrial ion channels in pancreatic β-cells: Novel pharmacological targets for the treatment of Type 2 diabetes

Pancreatic beta‐cells are central regulators of glucose homeostasis. By tightly coupling nutrient sensing and granule exocytosis, beta‐cells adjust the secretion of insulin to the circulating blood glucose levels. Failure of beta‐cells to augment insulin secretion in insulin‐resistant individuals leads progressively to impaired glucose tolerance, Type 2 diabetes, and diabetes‐related diseases. Mitochondria play a crucial role in β‐cells during nutrient stimulation, linking the metabolism of glucose and other secretagogues to the generation of signals that promote insulin secretion. Mitochondria are double‐membrane organelles containing numerous channels allowing the transport of ions across both membranes. These channels regulate mitochondrial energy production, signalling, and cell death. The mitochondria of β‐cells express ion channels whose physio/pathological role is underappreciated. Here, we describe the mitochondrial ion channels identified in pancreatic β‐cells, we further discuss the possibility of targeting specific β‐cell mitochondrial channels for the treatment of Type 2 diabetes, and we finally highlight the evidence from clinical studies.

LINKED ARTICLES

This article is part of a themed issue on Cellular metabolism and diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.10/issuetoc

New 2-Oxopyridine/2-Thiopyridine Derivatives Tethered to a Benzotriazole with Cytotoxicity on MCF7 Cell Lines and with Antiviral Activities

Background:

Perturbation of nucleic acids structures and confirmation by small molecules through intercalation binding is an intriguing application in anticancer therapy. The planar aromatic moiety of anticancer agents was inserted between DNA base pairs leading to change in the DNA structure and subsequent functional arrest.

Objective:

The final scaffold of the target compounds was annulated and linked to a benzotriazole ring. These new pharmacophoric features were examined as antiviral and anticancer agents against MCF7 and their effect on DNA damage was also assessed.

Methods:

A new series of fully substituted 2-oxopyridine/2-thioxopyridine derivatives tethered to a benzotriazole moiety (4a-h) was synthesized through Michael cyclization of synthesized α,β- unsaturated compounds (3a-e) with appropriate active methylene derivatives. The DNA damage study was assessed by comet assay. In silico DNA molecular docking was performed using Open Eye software to corroborate the experimental results and to understand molecule interaction at the atomic level.

Results:

The highest DNA damage was observed in Doxorubicin, followed by 4h, then, 4b, 4g, 4f, 4e, and 4d. The docking study showed that compound 4h formed Hydrogen Bonds (HBs) as a standard ligand with GSK-3. Compound 4h was the most active compound against rotavirus Wa, HAVHM175, and HSV strains with a reduction of 30%, 40%, and 70%, respectively.

Conclusion:

Compound 4h was the most active compound and could act as a prospective lead molecule for anticancer agent.

Sub-Chronic Consumption of Dark Chocolate Enhances Cognitive Function and Releases Nerve Growth Factors: A Parallel-Group Randomized Trial

Previous research has shown that habitual chocolate intake is related to cognitive performance and that frequent chocolate consumption is significantly associated with improved memory. However, little is known about the effects of the subchronic consumption of dark chocolate (DC) on cognitive function and neurotrophins. Eighteen healthy young subjects (both sexes; 20-31 years old) were randomly divided into two groups: a DC intake group (n = 10) and a cacao-free white chocolate (WC) intake group (n = 8). The subjects then consumed chocolate daily for 30 days. Blood samples were taken to measure plasma levels of theobromine (a methylxanthine most often present in DC), nerve growth factor (NGF), and brain-derived neurotrophic factor, and to analyze hemodynamic parameters. Cognitive function was assessed using a modified Stroop color word test and digital cancellation test. Prefrontal cerebral blood flow was measured during the tests. DC consumption increased the NGF and theobromine levels in plasma, enhancing cognitive function performance in both tests. Interestingly, the DC-mediated enhancement of cognitive function was observed three weeks after the end of chocolate intake. WC consumption did not affect NGF and theobromine levels or cognitive performance. These results suggest that DC consumption has beneficial effects on human health by enhancing cognitive function.

The Effect of a Single Dose of Dark Chocolate on Cardiovascular Parameters and Their Reactivity to Mental Stress

Objective: This study investigated the effect of a single administration of dark or milk chocolate on blood pressure (BP), heart rate (HR), and double product (DP) in young healthy women at rest and during acute mental stress.Method: Measurements consisted of anthropometry, BP, and HR. Mean arterial BP (MAP) and DP were computed. The relative reactivity of individual variables was quantified as to their percentage change during the rest or test of mental arithmetic (MA) with respect to the respective baseline value. All subjects underwent two tests of MA-one before chocolate administration and the second one 2 hours after chocolate (1 mg/g of body weight) ingestion.Results: Two hours after ingestion at rest, dark chocolate administration resulted in a significant increase in relative values of systolic BP and DP by 5.1% ± 1.4% and 13.7% ± 3.2%, respectively, compared to the responses in the milk chocolate group (-2.4% ± 1.6% and 0.6% ± 3.4%, respectively, p < 0.04 for both comparisons) without changes in diastolic BP, HR, and MAP. During MA-induced acute stress, the relative magnitude of the reactivity of diastolic BP, HR, MAP, and DP decreased by about 10, 16, 8, and 23 percentage points, respectively, 2 hours after ingestion of dark chocolate compared to the relative reactivity determined before dark chocolate ingestion. Milk chocolate failed to affect any of the above-mentioned parameters at rest or during stress.Conclusions: The single oral intake of 85% dark chocolate increased relative values of systolic BP and DP at rest but buffered the reactivity of diastolic BP, HR, MAP, and DP during mental stress, which was not found after ingestion of milk chocolate. Thus, dark chocolate might have a beneficial effect during acute stress due to its ability to buffer cardiovascular reactivity in young healthy women.

Total Phenolic, Anthocyanin, Catechins, DPPH Radical Scavenging Activity, and Toxicity of Lepisanthes alata (Blume) Leenh

Anthocyanins and catechin are natural antioxidants presented in many plants. Lepisanthes alata (Blume) Leenh is a plant with fruit that ripens to an intense red. This coloring suggests a high polyphenol content. However, limited information is available regarding the polyphenol or other antioxidant content in this fruit or its suitability as a food additive. The purpose of this research was to determine the total phenolic, total monomeric anthocyanin, catechin, epicatechin and epigallocatechin gallate content, DPPH radical scavenging activity, and toxicity in rind, flesh, seed, and whole fruit of L. alata. This research was conducted using an exploratory method with four analyses; samples from six parts of the plant were analyzed for polyphenols (rind, fruit pulp, seeds, whole fruit, bark, and leaves), four for anthocyanins (rind, fruit pulp, seeds, and whole fruit), and six parts of the plant for DPPH radical scavenging activity in water, methanol, and ethanol (rind, fruit pulp, seeds, whole fruit, bark, and leaves) and toxicity. This plant was found to contain high levels of polyphenol; the lowest level was measured in the flesh (0.64 mg GAE/g of DW) and the highest in the whole fruit (2.87 mg GAE/g of DW). The lowest anthocyanin content is found in the flesh and the highest in the rind with the respective average values of 672.27 mg/100 g FW and 1462.82 mg/100 g FW. Epicatechin is the major catechin in whole fruit and bark of L. alata. L. alata DPPH radical scavenging activity was in the range of 21.23 to 92.5% depending on the solvent, and the highest activity was recorded in bark in ethanol extract. No toxins were found in any part of the plant indicating that an extract from it could be safely used as a natural antioxidant supplement in processed foods to protect against free radicals.

Dark Chocolate Intake Positively Modulates Redox Status and Markers of Muscular Damage in Elite Football Athletes: A Randomized Controlled Study

Intensive physical exercise may cause increase oxidative stress and muscular injury in elite football athletes. The aim of this study was to exploit the effect of cocoa polyphenols on oxidative stress and muscular injuries induced by intensive physical exercise in elite football players. Oxidant/antioxidant status and markers of muscle damage were evaluated in 24 elite football players and 15 controls. Furthermore, the 24 elite football players were randomly assigned to either a dark chocolate (>85% cocoa) intake (n = 12) or a control group (n = 12) for 30 days in a randomized controlled trial. Oxidative stress, antioxidant status, and muscle damage were assessed at baseline and after 30 days of chocolate intake. Compared to controls, elite football players showed lower antioxidant power and higher oxidative stress paralleled by an increase in muscle damage markers. After 30 days of dark chocolate intake, an increased antioxidant power was found in elite athletes assuming dark chocolate. Moreover, a significant reduction in muscle damage markers (CK and LDH, p < 0.001) was observed. In the control group, no changes were observed with the exception of an increase of sNox2-dp, H₂O₂, and myoglobin. A simple linear regression analysis showed that sNox2-dp was associated with a significant increase in muscle damage biomarker release (p = 0.001). An in vitro study also confirmed that polyphenol extracts significantly decreased oxidative stress in murine myoblast cell line C2C12-derived. These results indicate that polyphenol-rich nutrient supplementation by means of dark chocolate positively modulates redox status and reduced exercise-induced muscular injury biomarkers in elite football athletes. This trial is registered with NCT03288623.

Antioxidant capacity of phenolics in Camellia nitidissima Chi flowers and their identification by HPLC Triple TOF MS/MS

Camellia nitidissima Chi (CNC) is a valuable medicinal and edible plant in China. In this study, CNC flowers were extracted with 95% ethanol, then partitioned into dichloromethane, ethyl acetate, n-butanol, and water fractions, with the antioxidant capacity of flavonoids and other phytochemicals in CNC flowers investigated for the first time. Results showed that the ethyl acetate fraction exhibited the strongest antioxidant capacity and highest total phenolic content (TPC) compared with the other fractions. Furthermore, in the ethyl acetate fraction, the 50% effective concentrations (EC₅₀) of ABTS⁺ and DPPH radical scavenging activities were 64.24 ± 1.80 and 78.80 ± 0.34 μg/mL, respectively, and the ferric reducing antioxidant power (FRAP) was 801.49 ± 2.30 μM FeSO₄ at 1,000 μg/mL. Pearson’s correlation coefficients and principal component analyses (PCA) for the TPC and antioxidant capacity of the five fractions indicated that the phenolic compounds were the major antioxidant constituents in the flowers. To exploit the antioxidants in CNC flowers, 21 phenolic compounds in the ethanolic extract fraction were identified by HPLC Triple TOF MS/MS, next, 12 flavonoids were isolated and elucidated, of which compounds 1–5 showed potent antioxidant capacity. In addition, the potential structure-activity relationship among these 12 flavonoids showed that (1) the o-catechol group in the B-ring was primarily responsible for the antioxidant capacity of flavonoids and (2) steric hindrance, produced by glycosides and other groups, could reduce the antioxidant capacity of the flavonoids.

Phytochemicals from Camellia nitidissima Chi Flowers Reduce the Pyocyanin Production and Motility of Pseudomonas aeruginosa PAO1

Camellia nitidissima Chi, known as a medicinal and edible plant in China, exhibits multiple bioactivities, especially antibacterial activity. In this study, we investigated the inhibitory effects of the dichloromethane fraction (DF) of C. nitidissima Chi flowers on the pyocyanin production, swarming motility, and swimming motility of Pseudomonas aeruginosa PAO1, at sub-minimum inhibitory concentrations. Results showed that the DF had a remarkable inhibitory effect on pyocyanin production without influencing P. aeruginosa PAO1 growth, and concentration-dependent inhibitory effects on swarming and swimming motility. The half maximal inhibitory concentrations (IC50) were 0.158 ± 0.009, 0.139 ± 0.004, and 0.334 ± 0.049 mg/mL for pyocyanin production, swarming motility, and swimming motility, respectively. Real-time RT-PCR showed that the DF significantly down-regulated the expressions of lasR (p < 0.05) and rhlR (p < 0.01). In addition, gallic acid, catechin, ellagic acid, chlorogenic acid, quercetin, and kaempferol were identified in the DF by HPLC Triple TOF MS/MS analysis. All six identified compounds showed inhibitory effects on pyocyanin production, swarming motility, and swimming motility, though ellagic acid showed the strongest effects, with IC50 values of 0.067 ± 0.002, 0.024 ± 0.008, and 0.020 ± 0.003 mg/mL, respectively. Thus, the inhibitory effects on P. aeruginosa PAO1 virulence factors might be attributable to these six and/or other compounds in the DF of C. nitidissima Chi flowers. Consequently, the C. nitidissima Chi flower, especially the DF, might be a potential quorum sensing inhibitor of P. aeruginosa PAO1.

Beneficial effect of a polyphenol-rich diet on cardiovascular risk: a randomised control trial

OBJECTIVES

There is previous epidemiological evidence that intake of polyphenol-rich foods has been associated with reduced cardiovascular disease risk. We aimed to investigate the effect of increasing dietary polyphenol intake on microvascular function in hypertensive participants.

METHODS

All participants completed a 4-week run-in phase, consuming <2 portions of fruit and vegetables (F&V) daily and avoiding berries and dark chocolate. Subjects were then randomised to continue with the low-polyphenol diet for 8 weeks or to consume a high-polyphenol diet of six portions F&V (including one portion of berries/day and 50 g of dark chocolate). Endothelium-dependent (acetylcholine, ACh) and endothelium-independent (sodium nitroprusside) vasodilator responses were assessed by venous occlusion plethysmography. Compliance with the intervention was measured using food diaries and biochemical markers.

RESULTS

Final analysis of the primary endpoint was conducted on 92 participants. Between-group comparison of change in maximum % response to ACh revealed a significant improvement in the high-polyphenol group (p=0.02). There was a significantly larger increase in vitamin C, carotenoids and epicatechin in the high-polyphenol group (between-group difference p<0.001; p<0.001; p=0.008, respectively).

CONCLUSIONS

This study has shown that increasing the polyphenol content of the diet via consumption of F&V, berries and dark chocolate results in a significant improvement in an established marker of cardiovascular risk in hypertensive participants.

TRIAL REGISTRATION NUMBER

NCT01319786.