Group Of Polyphenols Research Articles

Comparative study on the interaction between flavonoids with different core structures and hyaluronidase

Hyaluronidase (HAase) is an important enzyme involved in a promoting inflammation pathway. Flavonoids are a group of major polyphenols including flavonols (such as myricetin and rutin), dihydroflavones (such as naringin and hesperidin), and isoflavones (such as genistein and puerarin), which have been proved to possess anti-inflammatory effects. In this study, the binding of the six flavonoids to HAase was investigated by steady state and time-resolved fluorescence, circular dichroism (CD) spectroscopy and molecular docking methods. Fluorescence data reveal that the fluorescence quenching mechanism of HAase by flavonoids is all static quenching procedure regardless of their core structure. The binding affinity is strongest for rutin and ranks in the order rutin > hesperidin > myricetin > puerarin > genistein > naringin. The thermodynamic analysis implies that hydrophobic interaction, electrostatic force and hydrogen bonding are the main interaction forces. Synchronous fluorescence spectroscopy and CD spectroscopy indicate that flavonoids have the same core structure and have similar effects on the microenvironment around Trp and Tyr residues and the secondary structure of HAase. The results of molecular docking show that the binding of flavonoids with the catalytic amino acid residues of HAase may lead to the decrease of enzyme activity.

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.

How procyanidin C1 sticks to collagen: The role of proline rings

Molecular interactions between proteins and polyphenols are responsible for many natural phenomena like colloidal turbidity, astringency, denaturation of enzymes and leather tanning. Although these phenomena are well known, there are open questions about the specific interactions involved in the complexation process. In this work, Molecular Dynamic (MD) simulations and the topology of the electron density analysis were used to study the interactions between the flavonoid procyanidin C1 and a collagen fragment solvated in water. Root mean square deviation; root mean square fluctuation and hydrogen bonds occupancy were examined after 50 ns. The interactions were also analyzed by means of the quantum theory of atoms in molecules. Our results show that the main interactions are hydrogen bonds between –OH groups of the polyphenol and CO groups of the peptide bond. Stacking interactions between proline rings and phenol rings, that is CH⋯π hydrogen bonds, also stabilize the dynamic structure of the complex.

Phytochemical profiling and GC–MS analysis of Vitis rotundifolia pulp extract (Jumbo muscadine)

Now a days, phytochemical screening and GCMS analysis draw the attention of researchers, as it is the important tool to analyze secondary metabolites and bioactive compounds which are used to produce the herbal medicines, food colorants, flavors and fragrances. In this study bioactive compounds and phytochemical constituents of Jumbo muscadine grape pulp extract are analyzed. The extract has been characterized by UV and FTIR in which both the optical property and functional groups are identified. Absorption spectra of UV showed the highest peak at 270 nm which associates to the polyphenol and functional groups such as alcohol; alkene has been interpreted using FTIR spectrum. Presence of phytochemicals is confirmed by qualitative tests and quantified. Bioactive compounds are interpreted using gas chromatography–mass spectrometry analysis. This grape extract contains phenols, terpenoids, saponins and carbohydrates as major phytochemicals. Identified essential bioactive compounds of this extract include Glycerin, oleic acid, palmitic acid and 5-hydroxymethyl furfural.

Enhanced separation performance of Hg2+ in desulfurization wastewater using a tannin acid reduced graphene oxide membrane

• The tannin acid reduced graphene oxide membranes exhibit good separation performance. • The rejection rate of Hg 2+ could be enhanced by tannin acid modification. • The membrane was suitable for reusing without reducing the performance. • The rGO-TA membrane shows excellent potential in desulfurization wastewater treatment. In this study, the tannic acid reduced graphene oxide (rGO-TA) membrane was prepared by vacuum-assisted filtration method. The as-prepared membrane was characterized by Transmission electron microscope (TEM), atomic force microscope (AFM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). It was found that the GO membrane was modified by the polyphenolic hydroxyl groups in the tannic acid (TA), and the membrane structure was getting more compact. Besides, the separation performance of the rGO-TA membrane was evaluated, and the separation mechanism had been further explored. The effect of reduction degree, rGO-TA loading, initial concentration of Hg 2+ , and temperature were studied. The results show that the separation performance was related to the reduction degree of the rGO-TA membrane, the optimum Hg 2+ rejection rate of 91.61%, and the flux of 56.5 L·m −2 ·h −1 could be achieved. The separation performance was strongly dependent on the rGO-TA loading. The higher initial concentration of Hg 2+ could adversely affect the separation performance. The given temperature would change the hydration degree of the groups in the membrane and increase the Hg 2+ rejection rate. Moreover, the rGO-TA membrane exhibited an excellent regeneration performance (rejection rate of 78.74%) after three cycles.

Tunicate-inspired polyallylamine-based hydrogels for wet adhesion: A comparative study of catechol- and gallol-functionalities

HypothesisFunctional adhesives with excellent adhesive strength in wet as well as dry environments are actively studied for various applications. In particular, the adhesion mechanism of marine organisms has been imitated to achieve strong adhesion in wet environments. ExperimentsPolyallylamine (PAA) was modified with catechol groups (CA), which mimic the mussel adhesion proteins, and gallol groups (GA) found in tunicates to compare the gelation, self-healing, and adhesive properties of the modified polymers according to pH change. The effect of the Schiff base formation and antioxidant capacity exerted by polyphenolic groups were investigated by comparing the self-healing behaviors of the two hydrogels. Furthermore, the wet adhesion and antibacterial properties of the PAA-CA and PAA-GA hydrogels were evaluated in terms of the synergistic effects of the amino groups and catechol or gallol groups. FindingsThe self-crosslinkable PAA-CA and PAA-GA hydrogels showed high self-healing ability owing to these dynamic imine bonds. Furthermore, the PAA-based hydrogels showed higher adhesive strength in wet environments than in dry environments owing to the synergism between the catechol or gallol groups and amino groups. Overall, the PAA-GA hydrogels are superior to the PAA-CA ones, indicating that gallol-functionalized hydrogels have great potential as multifunctional adhesives.

Apple Pomace as a Source of Bioactive Polyphenol Compounds in Gluten-Free Breads.

Gluten-free products based on starch and hydrocolloids are deficient in nutrients and do not contain pro-health substances. Therefore, they should be enriched in raw materials naturally rich in antioxidants, especially if they are intended for celiac patients, prone to high oxidative stress. Apart from the traditionally used pseudo-cereals, seeds, vegetables and fruits, innovative substrates such as the by-product (especially in Poland) dry apple pomace could be applied. The study material consisted of gluten-free bread enriched with apple pomace. The content of individual polyphenols, the content of total polyphenol and flavonoids, and also the antioxidant potential of the bread were determined by the UPLC-PDA-MS/MS methods. It was observed that apple pomace was a natural concentrate of bioactive substances from the group of polyphenols. In summary, gluten-free bread with 5% content of apple pomace showed the highest organoleptic scores and contained high levels of phenolic compounds. The values of total phenolic content, and the amounts of flavonoids, phenolic acids and phloridzin in this bread were 2.5, 8, 4 and 21 times higher in comparison to control.

Effect of Green Tea Catechins on the Growth of MDA‐MB 468 Breast Cancer Cells

Breast cancer is the most commonly diagnosed cancer in women. Diet is considered an important factor in breast cancer prevention and studies suggest that green tea consumption has the potential to reduce breast cancer risk. Catechins, a group of polyphenols that are found in plants, have been shown to have anti-tumor effects . Many studies have investigated EGCG, but less is known about epicatechin. We investigated the inhibition of cell proliferation in the breast cancer cell lines, MDA-MB 468 after exposure to varying concentrations of EGCG and epicatechin. Changes in proliferation were determined using the MTT assay after exposing cells for 24 and 48 hours to concentrations of catechins ranging from 1μM to 500μM. We found that after 24-hr exposure, the cells significantly decreased in growth with a lower percent of cells remaining after exposure to 500μM EGCG. Percentage of cells was higher at 1μM when compared to 500μM . However, when the cells were exposed to epicatechin in that same time period, there was no significant difference. We found that as time increased from 24 to 48 hours, EGCG significantly inhibited the growth of cancer cells at 500μM . No effect was observed for epicatechin in growth as time increased. At an exposure of 500μM epicatechin, a higher percentage of cells were alive at 24 hours when compared to 48 hours but average values among experiments were not statistically significant. Our findings suggest that EGCG is a more potent inhibitor of triple negative breast cancer cell growth than epicatechin.

Research of hop polyphenols impact on malt hopped wort aroma formation model experiments

Currently, a lot of research is being done on the flavoring compounds of hops. However, much less attention has been paid to the aroma formation considering the hop polyphenol different groups by various methods at the wort hopping stage. Therefore, the main goal of the research is an impact of hopping conditions on the polyphenolic compounds, when the hop is extracted variously into both wort and water to better understand extraction conditions, mechanisms, and factors as well as aroma formation considering various groups of polyphenols. As shown the hop variety, boiling time, and treatment type affect the hop polyphenols amount extracted into the wort. Aromatics varied upon a hop variety and wort boiling time accompanying a positive softening effect regarding aroma formated from malt wort compounds comparing to hopped aqueous extracts. The research proved the most noticeable pH (7 and above) impact on aroma formation caused by the polyphenol conversion. As also shown the first time, a temperature and acidic pH doubled the rutin amount, as well as the best extraction of the prenylflavanoid isoxanthohumol, was achieved by boiling at an alkaline medium pH. The results obtained indicate that various hydrophilic amino acids containing in the wort can stabilize polyphenols affecting the quality indicators of beer produced from different grain raw materials.

Potential of non-<i>Saccharomyces</i> yeast for improving the aroma and sensory profile of Prokupac red wine

This work aimed to analyse the effect of non-Saccharomyces yeasts on the volatile composition, aromatic profile and sensory properties of wine made from autochthonous Serbian grape variety Prokupac (Vitis vinifera). Fermentation was performed with two commercial yeasts, Metschnikowia pulcherrima and Torulaspora delbrueckii, in pure and sequential fermentation with Saccharomyces cerevisiae. The standard analysis of produced wines indicated that the application of both non-Saccharomyces yeast (in pure or in sequential fermentation) significantly reduces the content of alcohol when compared to the control. The use of M. pulcherrima in both pure and sequential fermentation resulted in a higher content of different groups of polyphenols, anthocyanins and flavonoids or better colour characteristics compared to the wines obtained in fermentations with T. delbrueckii. HS-SPME GC/MS analysis revealed the presence of 27 different compounds in the wine samples, with higher alcohols and ethyl esters being the most dominant. It was proven that the presence of non-Saccharomyces yeasts in the initial stage of fermentation with later inoculation with S. cerevisiae contributes to increased complexity of the wine, as well as increased higher alcohol content and total extracts. Wines produced from sequential fermentation with T. delbrueckii showed floral and spice attributes, probably due to 1-pentanol and 2-phenylethanol detected in the wine, as well as to the large amount of ethyl acetate. The use of M. pulcherrima in pure fermentation resulted in wines with the lowest sensorial characteristics (i.e., lacking fruity and floral aroma) probably due to the lowest relative contribution of ethyl esters. The control wine in this study (from pure fermentation with S. cerevisie), had the most intense ‘red berries’ and ‘black berries’ note and low intensity of spices or vegetable aroma, which may be explained by the highest relative contribution of ethyl octanoate and ethyl decanoate. The PCA results also clearly differentiated the analysed samples produced in the sequential, pure and control fermentation trials, leading to the conclusion that the aromatic profile of Prokupac wines produced in sequential fermentation was more complex compared to the wines produced in pure fermentation.

Therapeutic effects of polyphenols in fermented soybean and black soybean products

• Soybean has a great amount of isoflavones and anthocyanins. • The major amount of isoflavones exists in glycoside form. • During Fermentation, microorganisms convert glycosides isoflavones to aglycone form. • Aglycones has more bioavailability than glycosides isoflavones in the human intestine. • Therapeutic effects of soybean increase after fermentation. Polyphenols are a group of bioactive compounds that act as natural antioxidant in plants. isoflavones and anthocyanins are two main groups of polyphenols that are found in soybean and black soybean, respectively. Fermented soybean products are consumed in eastern Asian countries for centuries. In these products, after fermentation the glycosides polyphenols are converted into aglycone form of them such as genistein and diadzein by the action of β-glucosidase enzyme of the microorganisms used in these processes. These conversions caused to enhance the bioavailability of these phenolic compound in human intestine leads to a higher beneficial and therapeutic effects such as anti-cancer, antiobesity, neuroprotective and antidiabetes. These health promoting effects arise from the antioxidant activity of these two types of polyphenols and also the estrogen like structure of isoflavones that result in their estrogenic activity in human body. This review provides an overview of the fermentation effect on the changes happened in the structure and composition of polyphenols in fermented soybean and black soybean products lead to an increase in the different therapeutic activity of them.

Total Synthesis of Mulberry Diels-Alder-Type Adducts Kuwanons G and H.

Mulberry Diels-Alder-type adducts (MDAAs) are a group of rare natural polyphenols biosynthetically derived from [4 + 2]-cycloaddition of chalcones and dehydroprenylphenols. In this study, kuwanons G (1) and H (2), two bioactive MDAAs with unique dehydroprenylflavonoid dienes, were totally synthesized for the first time in a biomimetic manner. The key features of the convergent route include the use of the Baker-Venkataraman rearrangement, alkylation of β-diketone, intramolecular cyclization, and Suzuki-Miyaura coupling to achieve the subunit diene.

The role of monodentate tetrahedral borate complexes in boric acid binding to a soil organic matter analogue

Boron is an essential plant micronutrient responsible for several important functions. Boron availability in soils may be influenced by binding with soil organic matter (SOM), particularly with aromatic diol and polyphenol groups on SOM. The mechanism by which aromatic diols bind boron, however, remains unclear. The objective of this work is to further investigate interaction between boric acid and varying concentrations of an aromatic, polyphenolic SOM analogue (tannic acid at 5, 10 and 20 g L−1) from pH = 5–9. UV/Visible spectroscopy showed boric acid enhanced tannic acid deprotonation at pH = 7.0 and 9.0, resulting in singly deprotonated tannic acid subunits. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) showed boric acid/tannic acid binding for all concentrations at pH = 7 and 9, whereas binding at pH = 5.0 was observed only at 20 g L−1 tannic acid. Uncomplexed boron species were not evident at pH = 9.0, but were detectable at pH = 7.0 at lower tannic acid concentrations and prevalent at pH = 5.0, qualitatively indicating binding affinity increases from pH = 5.0 to 9.0. ATR-FTIR results indicated tetrahedral coordination of boron upon complexation to tannic acid with a monodentate mechanism. These results collectively highlight a transition of solution planar boric acid to a tetrahedral, monodentate coordination with a single phenol group in tannic acid polyphenols. This contrasts with previous spectroscopic studies, which indicated bidentate tetrahedral or monodentate trigonal planar orientations prevail at aromatic diol sites. This work presents a previously unobserved boric acid coordination mechanism to an SOM analogue and, therefore, may better inform prediction and modeling of boron behavior in soils.

Encapsulation Systems for Delivery of Flavonoids: A Review

Encapsulation of bioactive compounds s been considered a promising tool for preserving these compounds. Several studies on dietary sources and health benefits of flavonoids, their chemical and stability properties, and encapsulation methods used for delivery of flavonoids were reviewed. Flavonoids comprise the main group of polyphenols widely found in fruits and vegetables responsible for numerous biological activities. They have a flavan nucleus with 15 carbon atoms organized in three rings and are categorized into six subgroups. The main dietary sources of flavonoids are fruits, vegetables, cereals, tea, and some herbs such as Viola odorata Linn. These compounds can prevent diseases such as cardiovascular, cancers, neurodegenerative, diabetes, and inflammatory bowel disease. Despite these beneficial biological activities, flavonoids are not stable against environmental conditions, have low water solubility and low bioavailability after oral administration, which restricts their application. Accordingly, encapsulation has been utilized in order to improve the stability and solubility of flavonoids. Various approaches such as spray drying, molecular complexes, liposomes, nanoparticles, emulsification, and multilamellar vesicles have been applied in the entrapment of flavonoids. Encapsulation can improve the stability of flavonoids as well as solubility, controlled release, and bioavailability.

Polyphenol content and antioxidant activity of beverage from dragron fruit peel powder and soy powder

Excessive oxidation reactions in body cells caused by dietary changes. This causes a chain reaction that damages the body cells. Excess oxidation reactions can be prevented by antioxidants. Polyphenol groups such as flavonoids, anthocyanins, and phenolics are the most active natural antioxidants. Soya powder and dragon fruit peel powder are a source of natural antioxidants. This research aims to analyse the antioxidant compounds on the mix of dragon fruit peel powder and soy powder as a source of antioxidant beverage. The research design used one factorial that is the ratio of soy powder and dragon fruit peel powder (0%: 100%; 25%:75%; 50%:50%; 75%:25%; 100%:0%). The result showed that the antioxidant compound from this mixture was flavonoid, anthocyanin, and phenol. The range pH of the beverage are 5,25-6,83, range of water content are 4,81-6,29%, range of phenol content are 250,33-908,00 mg/100g, range of flavonoid are 250,33-908,00 mg/100g, range of anthocyanin are 8,00-387,83 mg/100g and the IC50 of the beverage are 17,61-18,60.

Metabolite Differences of Polyphenols in Different Litchi Cultivars (Litchi chinensis Sonn.) Based on Extensive Targeted Metabonomics.

Litchi is an important fruit cultivated in tropical and subtropical areas with high nutritious and delicious flavor and the pulp is the main part of the fruit consumed. Previous studies found that litchi had high total phenol content and antioxidant activity, but most of them focused on the identification of single or a few phenolic components with a low throughput test, and the metabolic differences of cultivars are still unknown to a some extent. In this study we used widely targeted metabolome based on ultra-performance liquid chromatography coupled with mass spectrometry (UPLC-MS/MS) to analyze the polyphenol metabolites of five different genotypes of mature litchi fruit. A total of 126 polyphenol metabolites in eight categories were identified to reveal the composition and differences of polyphenol; 15 common differential metabolites and 20 specific differential metabolites to each cultivar were found for the first time. The results infer that flavonoids, flavonols, hydroxycinnamoyls and catechins are the main polyphenol metabolites of litchi pulp. Cluster analysis showed that there were three groups of polyphenols from high to low; early maturing Feizhixiao is a kind of high polyphenol content cultivars, especially in catechins, anthocyanins, flavonols, quinic acids and hydroxycinnamoyls. The polyphenols in the flesh of mature litchi are rich, and there are significant differences among cultivars; there was a level of correlation between the contents of phenolics and the maturity of litchi cultivars; the content of phenolics in early maturing litchi cultivars appeared higher than those of mid- to late-maturing cultivars. This experiment will provide significant reference information for cultivation, breeding, processing and consumption.

Kandungan Fenolik dan Flavonoid Total Daun Macaranga hispida (Blume) Mull. Arg sebagai Kandidat Obat Antidiabetes

Diabetes Mellitus (DM) is one of the non communicable diseases (NCDs) with the largest number of deaths in the world. The Macaranga hispida (Blume) Mull. Arg is a source of phenolic compounds. Phenolic is grouped as polyphenols group that widely functioned as antidiabetic. The α-glucosidase enzyme plays a role in the forming of glycoproteins and glycolipids. The α-glucosidase enzyme can be used for antidiabetic activity assay because of its capability on breaking down carbohydrate into glucose in the human small intestine. This study aimed to determine phenolic content, total flavonoid content, and antidiabetic activity of M. hispida leaves extract and its fraction. The extract and fraction were tested for the phenolic levels using Folin-Ciocalteau method, the total flavonoid using alumunium chloride method, and the antidiabetic activity using α-glukosidase method. The yield of methanolic extract of the Macaranga hispida was 10.23%. Phenolic content of the ethyl acetate fraction from the methanolic extract was 8.411 mg, equivalent to gallic acid/100 mg extract. Total flavonoid content was 6.14 ± 0.31b/b μg/mL. Antidiabetic activity assay of the extract and the fractions of Macaranga hispida resulted the highest antidiabetic activity (IC50) was in the ethyl acetate fraction with IC50 value 21.91 μg / mL.

Limited relationship between temporality of sensory perception and phenolic composition of red wines

In wine, polyphenols are closely associated with astringency, bitterness, color and aroma. Some of these sensory parameters have been reported to be dynamically perceived during wine tasting. In this study, time-dependent sensory methodologies (Temporal Dominance of Sensations or TDS, and Temporal-Check-All-That-Apply or TCATA) were used to characterize wines made from six grape varieties. Sensory analysis was contrasted against the phenolic composition of wines. Temporal sensory methods revealed differences among wines which did not reflect the limited differences observed between wine phenolics. However, some significant associations could be described, namely, detection time of bitterness with concentration of proanthocyanidin polymers, colorimetric variables with content of anthocyanins, and dominance and higher incidence of bitter taste with contents of tyrosol and flavonols. Astringency showed no relationship with any single polyphenol or specific group of polyphenols. It is concluded that, despite the major contribution of polyphenols to wine composition, their unique and independent influence on time associated sensory aspects should be critically scrutinized due to the multifactoriality of elements participating in the perception of a temporary sensation.

Effect of CTABr (surfactant) on the kinetics of formation of silver nanoparticles by Amla extract

The work reported for the first time in this article describes the kinetic study of silver nanoparticles formation using Phyllanthus emblica amla extract. The synthesized silver particles exhibit an intense surface plasmon resonance band in the visible region at 455 nm. The variation in concentrations of amla extract, Ag+ ions, cetyltrimethyl ammonium bromide (CTABr), and reaction time play crucial roles for nucleus formation and the growth processes. The Ag+ ions reduction into metallic Ag0 is due to the presence of polyphenolic groups in the amla extract and thereafter, their agglomeration into nanoparticles. Due to the formation of spherical Ag-nanoparticles there is a appearance of a sharp surface plasmon resonance band in the UV–visible region. Silver nanoparticles (AgNPs) were characterized by TEM, XRD and FTIR techniques.

The Interactions between Polyphenols and Microorganisms, Especially Gut Microbiota.

This review presents the comprehensive knowledge about the bidirectional relationship between polyphenols and the gut microbiome. The first part is related to polyphenols’ impacts on various microorganisms, especially bacteria, and their influence on intestinal pathogens. The research data on the mechanisms of polyphenol action were collected together and organized. The impact of various polyphenols groups on intestinal bacteria both on the whole “microbiota” and on particular species, including probiotics, are presented. Moreover, the impact of polyphenols present in food (bound to the matrix) was compared with the purified polyphenols (such as in dietary supplements) as well as polyphenols in the form of derivatives (such as glycosides) with those in the form of aglycones. The second part of the paper discusses in detail the mechanisms (pathways) and the role of bacterial biotransformation of the most important groups of polyphenols, including the production of bioactive metabolites with a significant impact on the human organism (both positive and negative).