The interaction and physicochemical properties of the starch-polyphenol complex: Polymeric proanthocyanidins and maize starch with different amylose/amylopectin ratios.

This study investigated the impact of polymeric proanthocyanidins (PPC) on the physicochemical characteristics of maize starch with varying amylose content, and their potential interaction mechanism. PPC with a lower content (1 %) reduced the viscoelasticity of the high amylose maize starch (HAM) system, inhibited amylose rearrangement, and enhanced its fluidity. However, excessive PPC restrained the interaction between PPC and amylose. In contrast to HAM, PPC improved the gelation ability of waxy maize starch (WAM) as PPC concentration was raised. PPC suppressed the recrystallization of starch during storage, and PPC had a superior inhibition influence on the retrogradation of WAM in comparison to HAM. This indicated that amylopectin was more likely to interact with PPC than amylose. Hydrogen bonds were the main driving force between PPC and starch chains, which was clarified by Fourier transform-infrared, nuclear magnetic resonance, X-ray diffraction, iodine bonding reaction, and dynamic light scattering data. Additionally, the mechanism of interaction between PPC and the two starch components may be similar, and variance in physicochemical attributes can be primarily credited to the percentage of amylose to amylopectin in starch.

Investigation of bovine ß-lactoglobulin-procyanidin complexes interactions and its utilization in O/W emulsion.

Procyanidins are bioactive polyphenols that have a strong affinity to proteins. Beta-lactoglobulin (BLG) is widely used as an emulsifier in the food and other industries. This study evaluated the interaction between BLG and A-type procyanidin dimer (PA2) using the spectroscopic, thermodynamic, and molecular simulation. PA2 decreased the transmissivity and quenched the intrinsic fluorescence of BLG, suggesting that the two molecules formed a complex. The binding of PA2 reduced the surface hydrophobicity and altered the conformation of BLG with increasing the random coil regions. Thermodynamic and isothermal titration calorimetry analyses suggested that the main driving force of PA2-BLG interaction was hydrophobic attraction. Molecular docking simulations were used to identify the main interaction sites and forces in the BLG-PA2 complexes, which again indicated that hydrophobic interactions dominated. In addition, the influence of PA2 on the ability of BLG to form and stabilize O/W emulsions was analyzed. Emulsions formulated using BLG-PA2 complexes contained relatively small droplets (D4,3 ≈ 0.7 µm) and high surface potentials (absolute value >50 mV). Compared to BLG alone, BLG-PA2 complexes improved the storage stability of the emulsions. This study provides valuable new insights into the formation, properties, and application of protein-polyphenol complexes as functional ingredients in foods.

Exploring the pharmacological action mechanism of Ligusticum Chuanxiong-Piper Longum couplet medicines on the treatment of migraine based on network pharmacology.

Objective: To study the mechanisms of the Ligusticum chuanxiong Hort.-Piper longum L. herbal pair (LPHP) in the treatment of migraine using network pharmacology. Methods: The active constituents of LPHP and their targets were searched for and screened using the Chinese Medicine System Pharmacology Database. Genes related to migraine were searched on GeneCards, Online Mendelian Inheritance in Man and other databases. Cytoscape was used to construct and combine active component-target and disease-target networks. The core target was screened by network topology analysis, and the Metascape database was used for gene ontology analysis of key targets and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis to explore the molecular mechanisms in the treatment of migraine. Results: A total of 28 active constituents of LPHP were obtained through database screening and literature review, and 60 cross-linking targets were obtained. The target sites were analysed using a protein-protein interaction network to obtain six target proteins with a greater degree of relevance. These were identified as the main targets for the treatment of hypertension, and these key targets were found to be associated with 20 signalling pathways, including neuroactive ligand-receptor interaction, the calcium signalling pathway, the cGMP-PKG signalling pathway, pathways in cancer and the cyclic adenosine 3',5'-cyclic monophosphate (cAMP) signalling pathway. Conclusion: This study reveals the molecular mechanism of LPHP in the treatment of migraine from the perspective of network pharmacology and provides a basis for further research and molecular mechanism research.

Effects of proanthocyanidins on the pasting, rheological and retrogradation properties of potato starch.

BACKGROUND: Proanthocyanidins (PAS) were complexed with potato starch (PS) to prepare polyphenol-starch complexes. The pasting, rheological and retrogradation properties of the complexes were investigated. RESULTS: The addition of PAS markedly affected the pasting, rheological and retrogradation properties of PS, especially at a concentration of 5% (w/w). Rapid viscosity analysis indicated that PAS significantly changed the viscosity, breakdown and setback value of PS. The rheological results showed that PAS decreased the flow behavior index and consistency coefficient, but increased the viscoelasticity of PS. Differential scanning calorimetry and X-ray diffraction indicated that PAS delayed the retrogradation of PS. Furthermore, scanning electron microscopy indicated that the morphologies of retrograded PS gels were greatly altered to a less compact structure with the presence of PAS. Moreover, Fourier transform infrared spectroscopy elucidated that PAS interacted with PS via a noncovalent interaction, and inhibited the retrogradation of PS. CONCLUSIONS: The findings suggested that supplementing PS with PAS might be an effective and convenient method for modifying the physicochemical properties of PS. © 2021 Society of Chemical Industry.

Protein-polyphenol functional ingredients: The foaming properties of lactoferrin are enhanced by forming complexes with procyanidin.

The solution turbidity and intrinsic fluorescence quenching increased after procyanidin was mixed with lactoferrin. The addition of procyanidin also caused a reduction in the surface hydrophobicity of the lactoferrin, suggesting procyanidin bound to non-polar patches on lactoferrin's surfaces. Moreover, the binding interaction caused an appreciable alteration in the structure of both the polyphenol and protein. Thermodynamic analysis indicated the interaction was spontaneous and mainly driven by entropy changes, suggesting that hydrophobic interactions dominated. A computational docking simulation provided insights into the location of the most-likely binding sites on the protein, as well as the nature of the interaction forces involved. In particular, both hydrophobic and hydrogen bonding were found to be important. The binding of the procyanidin to the lactoferrin enhanced its foaming properties. These results may lead to the development of a new class of natural functional ingredients that can be used in food products to improve their quality attributes.

Utilization of plant-based protein-polyphenol complexes to form and stabilize emulsions: Pea proteins and grape seed proanthocyanidins.

Plant-based proteins and polyphenols are increasingly being explored as functional food ingredients. Colloidal complexes were prepared from pea protein (PP) and grape seed proanthocyanidin (GSP) and the ability of the PP/GSP complexes to form and stabilize oil-in-water emulsions were investigated. The main interactions between PP and GSP were hydrogen bonding. The stability of PP-GSP complexes to environmental changes were studied: pH (2-9); ion strength (0-0.3 M); and temperature (30-90 °C). Emulsions produced using PP-GSP complexes as emulsifiers had small mean droplet diameters (~200 nm) and strongly negative surface potentials (~-60 mV). Compared to PP alone, PP-GSP complexes slightly decreased the isoelectric point, thermostability, and salt stability of the emulsions, but increased their storage stability. The presence of GSP gave the emulsions a strong salmon (red-yellow) color, which may be beneficial for some specific applications. These results may assist in the creation of more efficacious food-based strategies for delivering proanthocyanidins.

Interplay between mesenchymal stem cell and tumor and potential application.

Mesenchymal stem cells (MSCs) possess the capabilities of self-renewal and multipotent differentiation. Firstly isolated from bone marrow, MSCs are subsequently identified from various post-natal tissue types. Based the differentiation into tissue-specific cells, MSCs were capable of replacing damaged and diseased tissues. In addition, MSCs have been demonstrated to possess important immunomodulatory properties. Increasing data showed that MSCs exhibited tropism for sites of the tumor microenvironment and interacted with tumor cells closely through paracrine signaling. Therefore, better understanding of crosstalk between MSCs and tumor cells will be able to develop potential strategies in the treatment of tumors in the future. Herein, we summarize the research progress of the influence of MSCs on tumor cells and the prospect of their application in tumor therapy in this review.

Binding mechanism and antioxidant capacity of selected phenolic acid - ß-casein complexes.

Phenolic acids are added to some dairy products as functional ingredients. The molecular interactions between the phenolic acids and milk proteins impacts their functional performance and product quality. In this study, the interactions between a milk protein (ß-casein) and a number of phenolic acids was investigated: 3,4-dihydroxybenzoic acid (DA); gallic acid (GA); syringic acid (SA); caffeic acid (CaA); ferulic acid (FA); and, chlorogenic acid (ChA). The structural characteristics of the phenolic acids, such as type, hydroxylation, methylation, and steric hindrance, affected their binding affinity to ß-casein. The strength of the binding constant decreased in the following order: CaA > ChA > FA > SA > GA > DA. Cinnamic acid derivatives (CaA, FA, and ChA) exhibited a stronger binding affinity with ß-casein than benzoic acid derivatives (DA, GA, and SA). Hydrophobic forces and electrostatic interactions dominated the interactions of ß-casein with benzoic acid and cinnamic acid derivatives, respectively. The number of hydroxyl groups on the phenolic acids enhanced their binding ability, while steric hindrance effects reduced their binding ability. The influence of methylation depended on phenolic acid type. After binding with phenolic acids, the conformation of the ß-casein changed, with a loss of random coil structure, an increase in α-helix structure, and a decrease in surface hydrophobicity. Furthermore, the presence of ß-casein decreased the in vitro antioxidant capacities of the phenolic acids, especially for gallic acid. These findings provide some useful insights into the structure-activity relationships of the interaction between ß-casein and phenolic acids.

Analysis of inhibitory interaction between epigallocatechin gallate and alpha-glucosidase: A spectroscopy and molecular simulation study.

Alpha-glucosidase is one of the main enzymes responsible for digesting starch. Inhibiting its activity is therefore being targeted as a strategy for tackling diabetes. Certain food components have the potential to act as natural α-glucosidase (SCG) inhibitors, such as the polyphenols found in tea. In this study, epigallocatechin gallate (EGCG) was shown to strongly inhibit SCG activity (IC50 value = 3.7 × 10-5 M). Multi-spectroscopic binding molecular simulations indicated that EGCG spontaneously bound to SCG through a combination of hydrogen bonding and hydrophobic interactions. The hypothesis was supported by the results from intrinsic fluorescence quenching, conformational change, surface hydrophobicity decrease, and molecular docking analysis of the SCG after binding. Molecular docking provided powerful visual insights into the nature of the molecular interactions involved. This research provides important new information about the interaction mechanism of EGCG and SCG, which may be beneficial to the development of functional foods to prevent diabetes.

Investigation on the binding interaction between rice glutelin and epigallocatechin-3-gallate using spectroscopic and molecular docking simulation.

The interaction between plant protein and polyphenol is a topic of considerable interest. However, there is relatively little understanding about the interaction between rice protein and epigallocatechin-3-gallate (EGCG). The spectroscopy and computational docking program were used to investigate the potential interaction between rice glutelin (RG) and EGCG. It was found that the intrinsic fluorescence of RG could be quenched by EGCG, which indicated interaction occurred between them. Thermodynamic analysis elucidated that the interaction process between RG and EGCG happened spontaneously with hydrogen bond as the primary driving force. The ANS-fluorescence indicated that the surface hydrophobicity of RG reduced with the increasing of EGCG. Circular dichroism spectra and synchronous fluorescence gave further information for the conformational and microenvironmental changes of RG. Particularly, the α-helix structure reduced and random coil structure increased after the binding interaction. Furthermore, the computational docking program exhibited target sites in which the amino acid residues of RG and EGCG might be bound together.

Protein-polyphenol interactions enhance the antioxidant capacity of phenolics: analysis of rice glutelin-procyanidin dimer interactions.

Rice glutelin and procyanidins are often used in functional foods as sources of plant-based proteins and polyphenols, respectively, but little is currently known about the interactions between them. In our research, the interaction between rice glutelin and the B-type procyanidin dimer (PB2) was investigated. The presence of the PB2 decreased the α-helix and random coil structure of the rice protein and reduced its surface hydrophobicity. However, the PB2 did not adversely affect the functional performance of RG in emulsions. Conversely, the antioxidant capacity of the PB2 was enhanced in the presence of the rice protein. Fluorescence spectroscopy confirmed that the protein and PB2 formed molecular complexes, which were primarily the result of hydrophobic attractive forces. Molecular docking analysis provides insights into the nature of the interaction between the rice protein and PB2. This study provides valuable insights into the nature of the interactions between plant proteins and polyphenolic nutraceuticals.

Comparison of phytochemical profiles and antiproliferative activities of different proanthocyanidins fractions from Choerospondias axillaris fruit peels.

Epidemiological studies had indicated that the incidence of colorectal cancer is inversely correlated to the consumption of proanthocyanidins (PAs). In this study, five PAs fractions isolated from Choerospondias axillaris fruit peels with different mean degree of polymerization (mDP) were characterized and their antiproliferative effects on Caco-2 cells were investigated. MALDI-TOF-MS results indicated that PAs fractions were composed of procyanidins with DP up to 13-mers. All PAs fractions induced dose and time-dependent reductions of Caco-2 cell viability. The IC50 values of PAs fractions with increasing mDP were 240 ±â€¯16.0, 143 ±â€¯9.53, 87.0 ±â€¯3.55, 44.3 ±â€¯4.89, and 42.8 ±â€¯2.20 µg/mL after 24 h incubation, respectively. The observed reduction in Caco-2 cell viability was due to apoptosis via the activation of caspase-9, caspase-3, caspase-8 and the elevation of intracellular ROS generation. Moreover, the extent of the reduction in cell viability after exposure to PAs fractions was positively correlated with their mDP and galloylation. These results indicate that Choerospondias axillaris peel is a potential source of natural chemopreventive agents for the treatment of colorectal cancer.

Characterization of binding interaction between rice glutelin and gallic acid: Multi-spectroscopic analyses and computational docking simulation.

Many foods contain mixtures of plant dietary proteins and polyphenols, but there is currently a relatively poor understanding of the nature of the interactions between these components. In this study, the interaction of rice glutelin (RG) and gallic acid (GA) was characterized by spectroscopic and molecular docking techniques. The intrinsic fluorescence of RG quenched after the addition of GA, indicating that an interaction occurred. Thermodynamic analyses indicated that the binding process was spontaneous and the main driving forces were hydrogen bonds and van der Waals forces. The surface hydrophobicity of RG decreased with increasing GA. Furthermore, synchronous fluorescence and circular dichroism spectra provided insights into micro-environmental and conformational changes of RG. In particular, there was a reduction of α-helix structure and an increase of ß-sheet structure present in RG after the binding interaction. Finally, molecular docking analysis provided a visual representation of a single binding site where GA interacted with specific amino acid residues located in the active site of the RG.

Antioxidant activity of proanthocyanidins-rich fractions from Choerospondias axillaris peels using a combination of chemical-based methods and cellular-based assay.

An extract isolated from Choerospondias axillaris peels was separated into five fractions using size-exclusion chromatography. The structural composition and mean degree of polymerization (mDP) of these fractions were then characterized by acid-catalysis followed by HPLC analysis. The antioxidant activity of each fraction was determined using a combination of chemical-based methods (DPPH, ABTS(+) radical scavenging activity, ferric-reducing antioxidant power, and phosphomolybdate assay) and a cellular-based assay. All fractions tested were found to have high total phenolics contents and were rich in proanthocyanidins. The mDP of fractions (F1-F5) ranged from 1.92 to 9.25. When tested by the chemical-based assays, the antioxidant activity of the fractions did not depend on molecular weight of the phenolics. Conversely, when tested by the cellular-based assay the antioxidant activity actually decreased with increasing molecular weight of the proanthocyanidins. These experiments highlight the limitations of using chemical-based assays to establish the antioxidant activity of proanthocyanidins within biological systems.

Proanthocyanidins, Isolated from Choerospondias axillaris Fruit Peels, Exhibit Potent Antioxidant Activities in Vitro and a Novel Anti-angiogenic Property in Vitro and in Vivo.

The production of new blood vessels (angiogenesis) is an important stage in the growth and spread of cancerous tumors. Anti-angiogenesis is one strategy for controlling tumor progression. This study evaluated the antioxidant and anti-angiogenic activities of a proanthocyanidins (PAs) extract from Choerospondias axillaris peels. HPLC-MS analysis revealed that numerous oligomeric forms of the PAs were detected in the PAs extract, including dimers, trimers, tetramers, and flavan-3-ol monomers. The PAs extract possessed appreciable free radical scavenging activity (IC50/DPPH = 164 ± 7 µg/mL, IC50/ABTS = 154 ± 6 µg/mL), potent reducing power (0.930 ± 0.030 g AAE/g), and strong cellular antioxidant activity (EC50 = 10.2 ± 1.4 and 38.9 ± 2.1 µg/mL without or with PBS-wash, respectively). It could also retard various stages of angiogenesis, such as the migration of endothelial cells and the creation of tubes, without causing toxicity to the cells. With regard to intracellular signal transduction, the PAs extract attenuated the phosphorylation of Akt, ERK, and p38MAPK dose-dependently in endothelial cells from human umbilical veins. In transgenic zebrafish embryo, new blood vessel formation was suppressed by PAs extract in a concentration-dependent manner at 72 h post fertilization. Thus, these results suggest that PAs from C. axillaris peels could be a good source of natural inhibitors to target angiogenesis.

Potential physicochemical basis of Mediterranean diet effect: Ability of emulsified olive oil to increase carotenoid bioaccessibility in raw and cooked tomatoes.

Excipient emulsions have compositions and structures specifically designed to increase the bioavailability of nutraceuticals in foods that they are co-ingested with. In this study, olive oil excipient emulsions were shown to significantly increase the bioaccessibility of carotenoids from tomatoes using a simulated gastrointestinal tract (GIT) model (p<0.05): being 8.18±0.93%, 11.85±1.76% for raw tomato-buffer mixture, and cooked tomato-buffer mixture; While being 32.3±2.60%, 55.7±3.28% and 42.6±3.75% for raw tomato-emulsion mixture, cooked tomato-emulsion mixture (boiled together) and cooked tomato- emulsion mixture (tomato boiled alone). These effects were attributed to: (i) the ability of digested olive oil droplets to form mixed micelles in the small intestine that solubilized the carotenoids; and, (ii) the ability of natural antioxidants (phenolics) in the olive oil to protect the carotenoids from oxidation. Thermal treatment (boiling) significantly increased carotenoid bioaccessibility from the tomatoes digested with emulsion, which was attributed to plant tissue disruption at elevated temperatures facilitating carotenoid release (p<0.05). Carotenoid bioaccessibility was higher when the tomatoes were boiled with emulsions (55.7±3.28%) than when they were boiled alone and then added to emulsions (42.6±3.75%). In conclusion, this study indicates that olive oil emulsions boost the bioaccessibility and chemical stability of lipophilic nutraceuticals in tomatoes, which may make an important contribution to the potential health benefits of the Mediterranean diet.

Comparison of bioactivities and phenolic composition of Choerospondias axillaris peels and fleshes.

BACKGROUND: Choerospondias axillaris is both an edible and medicinal fruit. It has a growing popularity and economic importance due to its nutritive value and medicinal effects, but comprehensive information on the chemical composition and bioactivity of its fruits is still lacking. Therefore the aim of this study was to investigate the antioxidant, antimicrobial and antiproliferative effects and chemical composition of peel polyphenolic (PP) and flesh polyphenolic (FP) extracts from C. axillaris. RESULTS: The phenolics and flavonoids of peel were significantly higher than those of flesh. Ultra-performance liquid chromatography (UPLC) and ultra-performance liquid chromatography/electrospray ionization quadrupole time-of-flight-mass spectrometry (UPLC/ESI-QTOF-MS(2) ) analysis revealed that (+)-catechin and oligomeric procyanidins were the most abundant compounds in PP and FP. Both extracts exhibited strong ferric-reducing antioxidant power, total antioxidant activity and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH(•) )-scavenging ability. PP showed a significantly higher antimicrobial effect against tested strains than that of FP, in a dose-dependent manner. Furthermore, both extracts inhibited the growth of HepG2 and Caco-2 cells in a dose- and time-dependent manner, with IC50 values of 39.31 and 47.49 µg mL(-1) to HepG2 cells and 101.90 and 102.61 µg mL(-1) to Caco-2 cells respectively. CONCLUSION: This is the first detailed report on the chemical composition and bioactivities of C. axillaris fruits. © 2015 Society of Chemical Industry.

Effects of Yucca Extract on Feed Efficiency, Immune and Antioxidative Functions in Broilers

Effects of yucca extract (YE) on feed efficiency, immune and antioxidative function in Arbor Acres broilers were studied. One hundred and twenty-eight fourteen-day-old broiler chickens were randomly divided into four treatments with four replicates of 8 birds each. These four diets were formulated by adding 0, 100, 200 and 300 mg/kg YE to the basal diet. The results showed that: diets supplemented with 100 and 200 mg/kg YE increased average body weight gain, feed efficiency, IgG, IgM, T-AOC, CAT and SOD levels, and have positive effects on inducing immune organs' maturation. In addition, 100 mg treatment mainly improved the feed efficiency whereas 200 mg treatment mainly acted on immunity and anti-oxidation. In conclusion, YE can be used as a feed additive due to its capability to improve feed efficiency, immune and antioxidative function in broilers.

Separation and characterization of polyphenolics from underutilized byproducts of fruit production (Choerospondias axillaris peels): inhibitory activity of proanthocyanidins against glycolysis enzymes.

Bioactive proanthocyanidins were isolated from the peel of Choerospondias axillaris fruit, which is a waste product of the food processing industry. Compositional analysis indicated that the proanthocyanidins had extension units mainly consisting of epicatechin gallate or epicatechin, and terminal units mainly consisting of catechin. Numerous polymeric forms of the molecules were detected, including monomers, dimers, and trimers. Certain fractions exhibited strong α-amylase or α-glucosidase inhibition in a dose-dependent manner. Furthermore, their inhibitory activities depended on their degree of polymerization and galloylation. For example, the most bioactive fraction had α-amylase and α-glucosidase inhibitory activities (IC50 values) of 541 and 3.1 µg mL(-1), respectively. This study demonstrates that proanthocyanidins from C. axillaris peels can inhibit carbohydrate digestive enzymes in vitro and may therefore serve as antidiabetic ingredients in functional or medical foods.

Impact of in vitro simulated digestion on the potential health benefits of proanthocyanidins from Choerospondias axillaris peels.

The influence of passage through a simulated gastrointestinal tract (GIT) on the stability and bioaccessibility of proanthocyanidins isolated from fruit (Choerospondias axillaris) peel was studied. In addition, the effects of the simulated GIT on the antioxidant and α-glucosidase inhibitory activities of proanthocyanidins extracts were evaluated. Gastric digestion had little effect on total polyphenol content (TPC) or mean degree of polymerization (mDP) of crude and purified extracts. However, intestinal digestion led to a significant decrease (about 26% and 19%) in TPC and (about 12% and 7%) in mDP for crude and purified extracts, respectively. The observed reduction in TPC and mDP levels was attributed to interactions of proanthocyanidins with pancreatic enzymes, rather than due to the chemical conditions during digestion. Only small flavan-3-ol molecules (monomers, dimers and trimers) could diffuse into the dialysis tubing used to simulate the intestinal wall. Changes in antioxidant activity during digestion were correlated to changes in TPC. After simulated GIT digestion, over 85% of α-glucosidase inhibitory activity of both extracts was preserved. These results indicate that the majority of the proanthocyanidins maintained their biological activities after passage through the simulated GIT, and were therefore still capable of providing valuable health benefits.