Artemisia dracunculus L. polyphenols complexed to soy protein show enhanced bioavailability and hypoglycemic activity in C57BL/6 mice

Non-covalent binding of chlorogenic acid to myofibrillar protein improved its bio-functionality properties and metabolic fate

As natural antioxidants added to meat products, polyphenols can interact with proteins, and the acid-base environment influenced the extent of non-covalent and covalent interactions between them. This study compared the bio-functional characteristics and metabolic outcomes of the myofibrillar protein-chlorogenic acid (MP-CGA) complexes binding in different environments (pH 6.0 and 8.5). The results showed that CGA bound with MP significantly enhanced its antioxidant activity and inhibitory effect on metabolism enzymes. CGA bound deeply into the MP structure hydrophobic cavity at pH 6.0, which reduced its degradation by digestive enzymes, thus increasing its bio-accessibility from 59.5% to 71.6%. The digestion products of the two complexes exhibited significant differences, with the non-covalent MP-CGA complexes formed at pH 6.0 showing significantly higher concentrations of rhetsinine and piplartine, two well-known compounds to modulate diabetes. This study demonstrated that non-covalent binding between protein and polyphenol in the acidic environment held greater promising prospects for improving health.

Covalent polyphenols-proteins interactions in food processing: formation mechanisms, quantification methods, bioactive effects, and applications

Proteins and polyphenols are abundant in the daily diet of humans and their interactions influence, among other things, the texture, flavor, and bioaccessibility of food. There are two types of interactions between them: non-covalent interactions and covalent interactions, the latter being irreversible and more powerful. In this review, we systematically summarized advances in the investigation of possible mechanism underlying covalent polyphenols-proteins interaction in food processing, effect of different processing methods on covalent interaction, methods for characterizing covalent complexes, and impacts of covalent interactions on protein structure, function and nutritional value, as well as potential bioavailability of polyphenols. In terms of health promotion of the prepared covalent complexes, health effects such as antioxidant, hypoglycemic, regulation of intestinal microbiota and regulation of allergic reactions have been summarized. Also, the possible applications in food industry, especially as foaming agents, emulsifiers and nanomaterials have also been discussed. In order to offer directions for novel research on their interactions in food systems, nutritional value, and health properties in vivo, we considered the present challenges and future perspectives of the topic.

Metallothionein-Kidney Bean Polyphenol Complexes Showed Antidiabetic Activity in Type 2 Diabetic Rats by Improving Insulin Resistance and Regulating Gut Microbiota

Previous studies have shown that interaction between polyphenols and proteins can benefit health, but the mechanism of its antidiabetic effect has not been thoroughly elucidated. Therefore, this study aimed to investigate the impact of the metallothionein (MT)-kidney bean polyphenol complex on the blood glucose levels and gut microbiota of rats with type 2 diabetes mellitus (T2DM) induced by a high-fat diet combined with streptozotocin (STZ). After 7 weeks of intervention, the MT-kidney bean polyphenol complex can significantly improve the loss of body weight, the increase in blood glucose and blood lipids, and insulin resistance caused by T2DM in rats. In addition, it can effectively alleviate the damage to the pancreas and liver in rats. The MT-kidney bean polyphenol complex also significantly increased the concentrations of six short-chain fatty acids (SCFAs) in the intestinal contents of rats, especially acetic acid, propionic acid, and butyric acid (296.03%, 223.86%, and 148.97%, respectively). More importantly, the MT-kidney bean polyphenol complex can significantly reverse intestinal microflora dysbiosis in rats caused by T2DM, increase intestinal microorganism diversity, improve the abundance of various beneficial bacteria, and reshape the gut microbiota. In summary, the hypoglycemic effect of the MT-kidney bean polyphenol complex and its possible mechanism was expounded in terms of blood glucose level, blood lipid level, and gut microbiota, providing a new perspective on the development of the MT-kidney bean polyphenol complex as functional hypoglycemic food.

Soy Protein Isolate Interacted with Acrylamide to Reduce the Release of Acrylamide in the In Vitro Digestion Model

Acrylamide (AA), a common carcinogen, has been found in many dietary products.. This study aimed to explore the interaction of soybean protein isolate (SPI) with AA and further research the different effects of SPI on the AA release due to interactions in the in vitro digestion model. Analysis of variance was used to analyze the data. The results suggested that AA could bind with SPI in vitro, leading to the variation in SPI structure. The intrinsic fluorescence of SPI was quenched by AA via static quenching. The non-covalent (van der Waals forces and hydrogen bonding) and covalent bonds were the main interaction forces between SPI and AA. Furthermore, the release of AA significantly decreased due to its interaction with SPI under simulated gastrointestinal conditions. SPI had different effects on the AA release rate after different treatments. The thermal (80, 85, 90, and 95 °C for either 10 or 20 min) and ultrasound (200, 300, and 400 W for either 15, 30, or 60 min) treatments of SPI were useful in reducing the release of AA. However, the high pressure-homogenized (30, 60, 90, and 120 MPa once, twice, or thrice) treatments of SPI were unfavorable for reducing the release of AA.

The Influence of Flavonoid Dihydroquercetin on the Enzymatic Processes of Dough Ripening and the Antioxidant Properties of Bread

Bread is an integral part of the diet of the world population. Development of bread enriched with biologically active substances, including antioxidants, could be good nutritional support for human health. Among well-studied antioxidants, we can highlight dihydroquercetin, a flavonoid with outstanding antioxidant properties, such as anti-inflammatory activity, immunostimulatory properties, anti-cancer properties, and others. At the same time, the technology of bread enrichment must consider the possible negative effects of the additive on the technological processes and properties of the final product. The present work was carried out to evaluate the effect of dihydroquercetin on the enzymatic processes occurring during dough maturation and the antioxidant properties of the finished bread. Dihydroquercetin was added in amounts of 0.05 g, 0.07 g, and 0.1 g per 100 g of wheat flour and fermented with commercial baker’s yeast (Saccharomyces cerevisiae). The kinetics of pH and total titratable acidity (TTA) during dough fermentation showed that dihydroquercetin caused slight slowing of enzymatic processes. However, the dosage of dihydroquercetin did not cause statistically significant changes in the yeast concentration, which reached a level of 108 KOU/g after 2 h in all dough samples. Loss of dihydroquercetin during fermentation was established at a level of 20–25%. At the same time, an increase in the total amount of flavonoids in the dough after 2 h of fermentation and an increase in values of antioxidant activity were noted. The antioxidant properties of the bread also increased when it was enriched with dihydroquercetin (about 3.5–4 times) despite the fact that the total quantitative loss of antioxidant in the technological process was considerable (about 40%). A protective effect of the bread matrix on flavonoids during digestion was shown. Dihydroquercetin loss was about 25% regardless of the amount applied. This work clearly showed that addition of dihydroquercetin to a bread formulation represents a promising strategy for increasing the antioxidant properties of bread.

In silico analysis of dietary polyphenols and their gut microbial metabolites suggest inhibition of SARS-CoV-2 infection, replication, and host inflammatory mediators

The outcome of SARS-CoV-2 infection ranges from asymptomatic to severe COVID-19 and death resulting from an exaggerated immune response termed cytokine storm. Epidemiological data have associated consumption of a high-quality plant-based diet with decreased incidence and severity of COVID-19. Dietary polyphenols and their microbial metabolites (MMs) have anti-viral and anti-inflammatory activities. Autodock Vina and Yasara were used in molecular docking and dynamics studies to investigate potential interactions of 7 parent polyphenols (PPs) and 11 MMs with the α- and Omicron variants of the SARS-CoV-2 spike glycoprotein (SGP), papain-like pro-tease (PLpro) and 3 chymotrypsin-like protease (3CLpro), as well as host inflammatory mediators including complement component 5a (C5a), C5a receptor (C5aR), and C-C chemokine receptor type 5 (CCR5). PPs and MMs interacted to varying degrees with residues on target viral and host inflammatory proteins showing potential as competitive inhibitors. Based on these in silico findings, PPs and MMs may inhibit SARS-CoV-2 infection, replication, and/or modulate host immunity in the gut or periphery. Such inhibition may explain why people that consume a high-quality plant-based diet have less incidence and severity of COVID-19.Communicated by Ramaswamy H. Sarma.

Evaluation of Different Advanced Approaches to Simulation of Dynamic In Vitro Digestion of Polyphenols from Different Food Matrices-A Systematic Review

Phenolic compounds have become interesting bioactive antioxidant compounds with implications for obesity, cancer and inflammatory gastrointestinal pathologies. As the influence of digestion and gut microbiota on antioxidant behavior is yet to be completely elucidated, and due to limitations associated to in vivo studies, dynamic in vitro gastrointestinal models have been promoted. A systematic review was conducted of different databases (PubMed, Web of Science and Scopus) following PRISMA guidelines to assess different dynamic digestion models and assay protocols used for phenolic compound research regarding bioaccesibility and interaction with colonic microbiota. Of 284 records identified, those including dynamic multicompartmental digestion models for the study of phenolic compound bioaccesibility, bioactivity and the effects of microbiota were included, with 57 studies meeting the inclusion criteria. Different conditions and experimental configurations as well as administered doses, sample treatments and microbiological assays of dynamic digestion studies on polyphenols were recorded and compared to establish their relevance for the dynamic in vitro digestion of phenolic compounds. While similarities were observed in certain experimental areas, a high variability was found in others, such as administered doses. A description of considerations on the study of the digestion of phenolic compounds is proposed to enhance comparability in research.

Boosting the Bioaccessibility of Dietary Bioactives by Delivery as Protein-Polyphenol Aggregate Particles

Protein-polyphenol aggregate particles concurrently fortify a functional food product with healthy dietary proteins and concentrated polyphenols. However, what impact does ingestion of aggregate particles have on ultimate health relevance of either the polyphenolic molecules in the matrix or the protein molecules? Because human health benefits are contingent on bioavailability after ingestion, the fate of these molecules during transit in the gastrointestinal tract (GIT) will dictate their utility as functional food ingredients. This brief review explores diverse applications of protein-polyphenol particles in the food industry and the bioaccessibility of both bioactive polyphenolic compounds and edible proteins. Evidence to date suggests that complexation of phytoactive polyphenolics effectively enhances their health-relevant impacts, specifically because the phytoactives are protected in the protein matrix during transit in the GIT, allowing intact, non-degraded molecules to reach the colon for catabolism at the gut microbiome level, a prerequisite to realize the health benefits of these active compounds.

Antihyperglycemic and antidyslipidemic Effect of Moricandia suffruticosa in Normal and Streptozotocin-Induced Diabetic Rats

AIMS OF THE STUDY

The present work aimed to assess the antihyperglycemic and antohyperlipidemic effects ofMoricandia suffruticosa.

BACKGROUND

Moricandia suffruticosa (M. suffruticosa) is used in traditional medicine.

OBJECTIVE

The present study investigated the antihyperglycemic and antidyslipidemic effects of M. suffruticosa and its effect on glycogen content in normoglycemic and hyperglycemic rats.

METHODS

The effect of the aqueous extract of M. suffruticosa (AEMS) at a two doses of 100 and 140 mg/kg on blood glucose levels, lipid, lipoprotein profile, and glycogen content was examined in normal and streptozotocin(STZ)-induced diabetic rats. On the other hand, a preliminary phytochemical screening and quantification of phenolic, flavonoid, and tannin contents were carried out.

RESULTS

The results demonstrated that AEMS exhibits antihyperglycemic activity in diabetic rats during both acute and subchronic essays. Furthermore, AEMS revealed an antidyslipidemic effect concerning the level of triglycerides, total cholesterol, very-low density lipoprotein (VLDL), and non-high density lipoproteins (Non-HDL). In contrast, AEMS has not affected the value of glycemia, lipids, and lipoproteins in normal rats. In addition, AEMS is rich in several phytochemical compounds. Furthermore, AEMS revealed an important in vitro antioxidant activity.

CONCLUSION

In conclusion, the study demonstrates that M. suffruticosa exhibits an important antihyperglycemic effect in diabetic rats.

Biofortified Whey/Deglycosylated Whey and Chickpea Protein Matrices: Functional Enrichment by Black Mulberry Polyphenols

Morus nigra L. (black mulberry-BM) is a promising nutraceutical fruit containing biologically active polyphenols like anthocyanins, proanthocyanidins, catechins, and stilbenes, with well-established anti-inflammatory, antidiabetic, anti-obesity, and anticancer biofunctions. However, these health-promoting properties in raw fruit are greatly masked due to the presence of soluble and insoluble carbohydrates in excess amounts restricting daily intake of the required dose to achieve targeted effects. In the current study, different protein sources (defatted whey and chickpea flours) were optimized through different conditions to capture polyphenols from BM juice while diminishing its glucose content. To optimize polyphenol-protein interactions, various pHs (3.7, 4.2, and 4.7), matrix concentrations (20, 50, and 80 g protein/L), and incubation times (5, 20, and 45 min) were tested. In the present work, optimized BM polyphenol enriched whey matrix inhibited pro-inflammatory mediators and promoted Nrf-2 dependent cytoprotective enzyme expressions in lipopolysaccharide (LPS) induced macrophages at low doses. In addition, whey proteins were also subjected to an enzymatic deglycosylation process by using recently identified EndoBI-1 enzyme for the specific cleavage of N-glycan core in all glycan types including high mannoses, hybrids as well as complex glycans found on defatted whey proteins. After this process, the polyphenol sorption capacity of deglycosylated whey proteins was found to be significantly higher (37%) than the capacity of non-treated normal whey protein under optimized conditions. In conclusion, deglycosylation of protein matrices could be a novel strategy for efficient sorption/concentration of polyphenols from fruits and vegetables, however, more detailed studies are needed to understand this effect.

Enhanced bioavailability and anti-hyperglycemic activity of young apple polyphenols by complexation with whey protein isolates

This study aims to evaluate the effects of complexation of whey protein isolate (WPI) and young apple polyphenols (YAP) on the bioavailability and anti-hyperglycemic activity of YAP. Two types of WPI-YAP complexes were fabricated by mixing WPI with YAP at 25℃ (WPI-YAP) and 90℃ (WPI-YAP-H), respectively. The intermolecular interactions between WPI and YAP were investigated by fluorescence spectroscopy and circular dichroism analyses. The in vitro bioaccessibility and bioavailability of YAP were determined using a simulated gastrointestinal digestion and human Caco-2 cells model. It was found that the total polyphenols transport efficiency was improved from 39.8% (YAP) to 48.2% (WPI-YAP) and 56.1% (WPI-YAP-H), indicating that the bioavailability of YAP was improved by complexation with WPI. Besides, after complexation with WPI, YAP displayed an improved in vivo effect on alleviating the increase in postprandial blood glucose level than the pure YAP, with WPI-YAP-H showing a better effect. This finding indicates that co-complexation of YAP with WPI is an effective way to improve the functionality of YAP, and the WPI-YAP complexes are also expected to have potential application in designing YAP-containing functional foods. PRACTICAL APPLICATION: The research provided a method to improve the bioavavibility of polyphenols, and the WPI-YAP complex can be developed in designing polyphenols related functional foods.

Designing a Clinical Study With Dietary Supplements: It's All in the Details

A successful randomized clinical trial of the effect of dietary supplements on a chosen endpoint begins with developing supporting data in preclinical studies while paying attention to easily overlooked details when planning the related clinical trial. In this perspective, we draw on our experience studying the effect of an ethanolic extract from Artemisia dracunculus L. (termed PMI-5011) on glucose homeostasis as a potential therapeutic option in providing resilience to metabolic syndrome (MetS). Decisions on experimental design related to issues ranging from choice of mouse model to dosing levels and route of administration in the preclinical studies will be discussed in terms of translation to the eventual human studies. The more complex considerations in planning the clinical studies present different challenges as these studies progress from testing the safety of the dietary supplement to assessing the effect of the dietary supplement on a predetermined clinical outcome. From the vantage point of hindsight, we will outline potential pitfalls when translating preclinical studies to clinical studies and point out details to address when designing clinical studies of dietary supplements.

The reciprocal interaction between polyphenols and other dietary compounds: Impact on bioavailability, antioxidant capacity and other physico-chemical and nutritional parameters

Polyphenols are plant secondary metabolites, whose biological activity has been widely demonstrated. However, the research in this field is a bit reductive, as very frequently the effect of individual compound is investigated in different experimental models, neglecting more complex, but common, relationships that are established in the diet. This review summarizes the data that highlighted the interaction between polyphenols and other food components, especially macro- (lipids, proteins, carbohydrates and fibers) and micronutrients (minerals, vitamins and organic pigments), paying particular attention on their bioavailability, antioxidant capacity and chemical, physical, organoleptic and nutritional characteristics. The topic of food interaction has yet to be extensively studied because a greater knowledge of the food chemistry behind these interactions and the variables that modify their effects, could offer innovations and improvements in various fields ranging from organoleptic, nutritional to health and economic field.

Covalent and non-covalent interactions of cyanidin-3-O-glucoside with milk proteins revealed modifications in protein conformational structures, digestibility, and allergenic characteristics

Currently, there is a need to explore the effects of different types of protein-anthocyanin complexations, as well as the possible changes in the nutrition and allergenicity of the formed complexes. Here, we systematically investigated the covalent and non-covalent interactions between cyanidin-3-O-glucoside (C3G) and two major milk proteins, α-casein (α-CN) and β-lactoglobulin (β-LG). Fluorescence quenching data showed that, under non-covalent conditions, C3G quenched the fluorescence of the two proteins via a static process, with the interaction forces being revealed; for covalent products, decreased fluorescence intensities were observed with red shifts in the λ_max. Multiple spectroscopic analyses implied that C3G-addition induced protein structural unfolding through transitions between the random coil and ordered secondary components. With a two-stage simulated gastrointestinal (GI) digestion model, it was seen that covalent complexes, not their non-covalent counterparts, showed reduced protein digestibility, ascribed to structural changes resulting in the unavailability of enzyme cleaving sites. The GI digests displayed prominent 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation-scavenging abilities (3.8-11.1 mM Trolox equivalents per mL digest), in contrast to the markedly reduced 1,1-diphenyl-2-picrylhydrazyl radical-scavenging capacities. Additionally, covalent protein-C3G complexes, but not their non-covalent counterparts, showed lower IgE-binding levels in comparison to the native control. This study provides new understanding for the development of anthocyanin-milk protein systems as functional ingredients with health-beneficial properties.

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

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

Investigation on the interaction of acrylamide with soy protein isolate: Exploring the binding mechanism in vitro

Acrylamide (AA), which is a carcinogen in humans, has been a research focus in terms of food risk assessment. However, few published studies have explored protein strategies to reduce the health risks of AA. The objective of this study was to investigate the binding of AA with soy protein isolate (SPI) and elucidate the binding mechanism. The results showed that AA could bind with nontreated, heat-treated, high-pressure homogenization-treated, and ultrasound-treated SPI in vitro. Fourier-transform infrared spectroscopy suggested that secondary structure of SPI changed significantly after binding with AA in the nontreated and different treated groups. Moreover, fluorescence quenching experiments suggested that the quenching of SPI by AA was static quenching and hydrogen bonds, hydrophobic interactions, and van der Waals forces were involved in this process. PRACTICAL APPLICATION: The study of SPI and AA binding could provide a new perspective for reducing the bioaccessibility of AA in human body by using protein. The results showed that SPI could potentially be used as a novel health strategy to reduce the harm of AA in the human body.

Evaluation of the status quo of polyphenols analysis: Part I-phytochemistry, bioactivity, interactions, and industrial uses

Phytochemicals, especially polyphenols, are gaining more attention from both the scientific community and food, pharmaceutical, and cosmetics industries due to their implications in human health. In this line, lately new applications have emerged, and of great importance is the selection of accurate and reliable analytical methods for better evaluation of the quality of the end-products, which depends on diverse process variables as well as on the matrices and on the physicochemical properties of different polyphenols. The first of a two-part review on polyphenols will address the phytochemistry and biological activities of different classes of polyphenols including flavonoids, lignans and flavanolignans, stilbenoids, tannins, curcuminoids, and coumarins. Moreover, the possible interactions of polyphenols and current and potential industrial applications of polyphenols are discussed.

Binding affinity, antioxidative capacity and in vitro digestion of complexes of grape seed procyanidins and pork, chicken and fish protein

Studies have reported that procyanidins can interact with proteins, thereby affecting their structure, function, and bioaccessibility. In this paper, we investigated the interaction between grape seeds procyanidins (GSP) and animal source protein (from pig, chicken and fish), and the effects on the protein structure, antioxidant capacity and bioaccessibility of GSP. Fluorescence results showed that the binding constant of GSP-protein complex was 10-10⁴ M^-1, and the main forces were van der Waals force, hydrogen bonds and hydrophobic interactions. The antioxidant capacity of GSP was masked by GSP-protein complexes formed. The circular dichroism indicated that GSP had an effect on the content of α-helix and β-sheet in the secondary structure of pork and chicken proteins, but had little effect on the secondary structure of fish protein. The results showed that the protein can bind to GSP and affect its antioxidant activity and bioaccessibility. This study can provide reference for further study on the digestion and absorption of the complexes and offer health guidance in the preparation of diets.

The DESIGNER Approach Helps Decipher the Hypoglycemic Bioactive Principles of Artemisia dracunculus (Russian Tarragon)

Complementing classical drug discovery, phytochemicals act on multiple pharmacological targets, especially in botanical extracts, where they form complex bioactive mixtures. The reductionist approach used in bioactivity-guided fractionation to identify single bioactive phytochemicals is inadequate for capturing the full therapeutic potential of the (bio)chemical interactions present in such complex mixtures. This study used a DESIGNER (Deplete and Enrich Select Ingredients to Generate Normalized Extract Resources) approach to selectively remove the known bioactives, 4'-O-methyldavidigenin (1; 4,2'-dihydroxy-4'-methoxydihydrochalcone, syn. DMC-1) and its isomer 4-O-methyldavidigenin (2; syn. DMC-2), from the mixture of phytochemicals in an ethanol extract from Artemisia dracunculus to determine to what degree the more abundant 2 accounts for the established antidiabetic effect of the A. dracunculus extract. Using an otherwise chemically intact "knock-out extract" depleted in 2 and its regioisomer, 1, in vitro and in vivo outcomes confirmed that 2 (and likely 1) acts as major bioactive(s) that enhance(s) insulin signaling in skeletal muscle, but also revealed that 2 does not account for the breadth of detectable biological activity of the extract. This is the first report of generating, at a sufficiently large preparative scale, a "knock-out extract" used as a pharmacological tool for in vitro and in vivo studies to dissect the biological impact of a designated bioactive in a complex phytochemical mixture.

Interaction between soybean protein and tea polyphenols under high pressure

Tea polyphenols (TP) and soybean proteins (SP) are important materials in food industry. High hydrostatic pressure (HHP) is a useful tool for improvement of protein's function. This study evaluated the interactions between the polyphenol and HHP-treated protein using circular dichroism, fluorescence spectroscopy and molecular modeling. The high pressure at 400 MPa significantly modified the secondary structure of SP by increasing the β-sheet content and decreasing the α-helix content, while the addition of 0.1% (w/v) tea ployphenol appeared to protect the α-helix structure. The surface hydrophobicity decreased with HHP treatment and the addition of TP. The optimal solubility of native SP was 0.258 g/mL at 0.08% (w/v) TP. Together with HHP treatment; TP increased the protein solubility to 0.50 g/mL and the emulsifying activity was enhanced approximately three times, up to 43.5%. The micro-texture of SP matrix was also improved with TP and HHP treatment. Both the hydrogen bonding and hydrophobic interaction between TP and SP were elucidated using docking method. Apart from the hydrogen bonding, the Pi-Pi interaction was observed in the binding of phenolic compounds to 7S or 11S globular protein.

Interaction between rice bran albumin and epigallocatechin gallate and their physicochemical analysis

Epigallocatechin gallate (EGCG) is sensitive to heat thus its application in food industry is limited. In this work, rice bran albumin protein (RAP) was used as a carrier for EGCG. RAP-EGCG complexes (RAPE) were prepared with the binding number n of 0.0505:1 (EGCG: RAP, w/w) and binding constant K of (0.74 ± 0.002) × 10⁴ M^-1, which suggests that hydrogen bond/van der Waals forces played important roles in such binding. FTIR analysis demonstrated that EGCG could induce the secondary structure changes of RAP above the ratio of 1.92:1 (EGCG:RAP, w/w). Dynamic light scattering and scanning electron microscope results showed that EGCG could trigger RAP association. Furthermore, the EGCG stability in RAPE was significantly improved than that of free EGCG in 10-60 °C. The antioxidant ability of EGCG in RAPE was partially retained. These findings prove that RAP is a potential carrier for polyphenols and is beneficial for mechanism investigation between protein and polyphenols.

An Extract of Artemisia dracunculus L. Promotes Psychological Resilience in a Mouse Model of Depression

Stress-induced peripheral inflammation contributes to depression-like behaviors in both human and experimental models. PMI 5011, a botanical extract of Artemisia dracunculus L., was previously shown to have multiple bioactivities, including anti-inflammatory activity. In this work, using a repeated social defeat stress (RSDS) model of depression, we demonstrate that oral administration of the botanical extract PMI 5011 promotes resilience to RSDS-mediated depression-like phenotypes. We also show that the behavioral improvements are associated with attenuation of stress-mediated induction of inflammatory cytokines in the periphery and alteration of synaptic plasticity in the nucleus accumbens (NAc). Our studies provide experimental evidence that botanical extracts such as PMI 5011, which target pathological mechanisms (i.e., peripheral inflammation) not addressed by currently available antidepressants, could be further developed as novel therapeutics for the treatment of stress disorders and anxiety in humans.

Polyphenols and Their Interactions With Other Dietary Compounds: Implications for Human Health

Regular and optimal intake of polyphenols associates with numerous health-promoting effects. Bioavailability and activity of polyphenols depend on foods' structure and interactions with other food constituents, especially proteins, lipids, and carbohydrates. Polyphenols-proteins interactions can result in various biological effects, such as sense of astringency. So far, polyphenols interactions with food lipids have not been of special importance, except in case of plant oils. Polyphenols-carbohydrates interactions can influence the organoleptic properties, while interactions with dietary fibers are particularly significant. Polyphenols can decrease the synthesis of fats and fatty acids in the liver, or delay their absorption in intestines. Also, polyphenols can slow down digestion of carbohydrates, through the inhibition of digestive enzymes or modulation of glucose uptake. Both animal and plant proteins have low impact on the bioavailability of polyphenols, but some in vitro studies reported that milk proteins could enhance intestinal absorption of polyphenols from tea. Dietary fats may alter the passage of polyphenols through gastrointestinal tract and impact absorption of more hydrophobic polyphenols in particular. While some studies reported that associations with carbohydrates could decrease bioavailability of polyphenols, the others showed the opposite effects. Macronutrients can be used for encapsulation of polyphenols, which can increase their bioavailability and ensure controlled and targeted release. Polyphenols' interactions in the body include their incorporation in cell membranes which causes changes in fatty acid profile and impacts membrane-bound transporters and enzymes. Finally, gut microbiota plays essential role in metabolism of both polyphenols and macronutrients and thus can have great impact on their interactions.

Food processing strategies to enhance phenolic compounds bioaccessibility and bioavailability in plant-based foods

Phenolic compounds are important constituents of plant-based foods, as their presence is related to protective effects on health. To exert their biological activity, phenolic compounds must be released from the matrix during digestion in an absorbable form (bioaccessible) and finally absorbed and transferred to the bloodstream (bioavailable). Chemical structure and matrix interactions are some food-related factors that hamper phenolic compounds bioaccessibility and bioavailability, and that can be counteracted by food processing. It has been shown that food processing can induce chemical or physical modifications in food that enhance phenolic compounds bioaccessibility and bioavailability. These changes include: (i) chemical modifications into more bioaccessible and bioavailable forms; (ii) cleavage of covalent or hydrogen bonds or hydrophobic forces that attach phenolic compounds to matrix macromolecules; (iii) damaging microstructural barriers such as cell walls that impede the release from the matrix; and (iv) create microstructures that protect phenolic compounds until they are absorbed. Indeed, food processing can produce degradation of phenolic compounds, however, it is possible to counteract it by modulating the operating conditions in favor of increased bioaccessibility and bioavailability. This review compiles the current knowledge on the effects of processing on phenolic compounds bioaccessibility or bioavailability, while suggesting new guidelines in the search of optimal processing conditions as a step forward towards the design of healthier foods.

An Overview of Herbal Products and Secondary Metabolites Used for Management of Type Two Diabetes

Diabetes mellitus is a common effect of uncontrolled high blood sugar and it is associated with long-term damage, dysfunction, and failure of various organs. In the adult population, the global prevalence of diabetes has nearly doubled since 1980. Without effective prevention and management programs, the continuing significant rise in diabetes will have grave consequences on the health and lifespan of the world population, and also on the world economy. Supplements can be used to correct nutritional deficiencies or to maintain an adequate intake of certain nutrients. These are often used as treatments for diabetes, sometimes because they have lower costs, or are more accessible or "natural" compared to prescribed medications. Several vitamins, minerals, botanicals, and secondary metabolites have been reported to elicit beneficial effects in hypoglycemic actions in vivo and in vitro; however, the data remain conflicting. Many pharmaceuticals commonly used today are structurally derived from natural compounds from traditional medicinal plants. Botanicals that are most frequently used to help manage blood glucose include: bitter melon (Momordica charantia), fenugreek (Trigonella foenum graecum), gurmar (Gymnema sylvestre), ivy gourd (Coccinia indica), nopal (Opuntia spp.), ginseng, Russian tarragon (Artemisia dracunculus), cinnamon (Cinnamomum cassia), psyllium (Plantago ovata), and garlic (Allium sativum). In majority of the herbal products and secondary metabolites used in treating diabetes, the mechanisms of action involve regulation of insulin signaling pathways, translocation of GLUT-4 receptor and/or activation the PPARγ. Several flavonoids inhibit glucose absorption by inhibiting intestinal α-amylase and α-glucosidase. In-depth studies to validate the efficacies and safeties of extracts of these traditional medicinal plants are needed, and large, well designed, clinical studies need to be carried out before the use of such preparations can be recommended for treatment and/or prevention of diabetes. The main focus of this review is to describe what we know to date of the active compounds in these, along with their glucose-lowering mechanisms, which are either through insulin-mimicking activity or enhanced glucose uptake.

Interactions of β-Conglycinin (7S) with Different Phenolic Acids-Impact on Structural Characteristics and Proteolytic Degradation of Proteins

p-Coumalic acid (PCA), caffeic acid (CA), gallic acid (GA) and chlorogenic acid (CGA) are the major phenolic acids that co-exist with soy protein components in foodstuffs. Surprisingly, there are only a handful of reports that describe their interaction with β-Conglycinin (7S), a major soy protein. In this report, we investigated the interaction between phenolic acids and soy protein 7S and observed an interaction between each of these phenolic acids and soy protein 7S, which was carried out by binding. Further analysis revealed that the binding activity of the phenolic acids was structure dependent. Here, the binding affinity of CA and GA towards 7S was found to be stronger than that of PCA, because CA and GA have one more hydroxyl group. Interestingly, the binding of phenolic acids with soy protein 7S did not affect protein digestion by pepsin and trypsin. These findings aid our understanding of the relationship between different phenolic acids and proteins in complex food systems.

Comparison of soymilk and probiotic soymilk effects on serum high-density lipoprotein cholesterol and low-density lipoprotein cholesterol in diabetic Wistar rats

BACKGROUND

Soy milk (SM) and its fermented products are identified as rich sources of bioactive compounds helping to manage and to reduce the risk of chronic disease. This study aimed to compare the effects of SM and probiotic SM (PSM) consumption on serum low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) in diabetic Wistar rats.

METHODS

Probiotic SM was prepared by fermentation of the plain SM with a native strain of Lactobacillus plantarum. 20 streptozotocin-nicotinamide-induced diabetic Wistar rats were divided into two groups based on the type of administered SM (SM group and PSM group). The animals were fed with 1 ml/day of either soy or PSM for 21 days. The serum lipoprotein levels were analyzed at baseline and the end of the intervention period.

RESULTS

HDL-C increased significantly in PSM group. Furthermore, this group showed more percent of change in increased HDL-C in compression with SM group (P < 0.050). Regarding LDL-C level, rats fed with SM was not significantly different from the PSM group (P < 0.050); though, this biomarker was reduced in both group.

CONCLUSION

Probiotic SM could modulate blood lipoprotein levels. Thus, it may be considered in managing diabetes complications and atherosclerotic risks.

Interactions of polyphenols with carbohydrates, lipids and proteins

Polyphenols are secondary metabolites in plants, investigated intensively because of their potential positive effects on human health. Their bioavailability and mechanism of positive effects have been studied, in vitro and in vivo. Lately, a high number of studies takes into account the interactions of polyphenols with compounds present in foods, like carbohydrates, proteins or lipids, because these food constituents can have significant effects on the activity of phenolic compounds. This paper reviews the interactions between phenolic compounds and lipids, carbohydrates and proteins and their impact on polyphenol activity.