Natural polyphenols alleviated lipid peroxidation-induced modification on BSA

Inhibitory mechanisms of polyphenols on heme protein-mediated lipid oxidation in muscle food: New insights and advances

Lipid oxidation is a major cause of quality deterioration that decreases the shelf-life of muscle-based foods (red meat, poultry, and fish), in which heme proteins, particularly hemoglobin and myoglobin, are the primary pro-oxidants. Due to increasing consumer concerns over synthetic chemicals, extensive research has been carried out on natural antioxidants, especially plant polyphenols. The conventional opinion suggests that polyphenols inhibit lipid oxidation of muscle foods primarily owing to their strong hydrogen-donating and transition metal-chelating activities. Recent developments in analytical techniques (e.g., protein crystallography, nuclear magnetic resonance spectroscopy, fluorescence anisotropy, and molecular docking simulation) allow deeper understanding of the molecular interaction of polyphenols with heme proteins, phospholipid membrane, reactive oxygen species, and reactive carbonyl species; hence, novel hypotheses regarding their antioxidant mechanisms have been formulated. In this review, we summarize five direct and three indirect pathways by which polyphenols inhibit heme protein-mediated lipid oxidation in muscle foods. We also discuss the relation between chemical structures and functions of polyphenols as antioxidants.

Red Beetroot and Banana Peels as Value-Added Ingredients: Assessment of Biological Activity and Preparation of Functional Edible Films

In the present study, water extracts from banana and red beetroot peels were evaluated as a potential source of biologically active compounds for the formulation of edible films. Using spectrophotometric and HPLC-DAD methodologies, banana peel extract was found to be a valuable source of dopamine (156.08 mg L−1), while red beetroot peel extract was abundant in red-violet pigments betacyanins (90.1 mg betanin L−1). The biological activity of the extracts was studied by determining their effects on macromolecular models, including DNA (plasmid phiX RF1 DNA), protein (bovine serum albumin), and lipid (linoleic acid) models, as well as on continuous human cell lines of colon cancer Caco-2 and hepatocellular liver cancer Hep G2 at concentrations of 0.2 and 1 mg mL−1. Results showed that the extracts had no adverse effects and both were further used for the formulation of edible films using alginate in combination with three types of plant proteins—rice, peanut, and pumpkin. In general, edible films based on banana peel extract were characterized by better bioactive properties compared with the films based on red beetroot peel extract. The addition of peanut proteins into the formulations resulted in the most desirable bioactive profile of the formulated edible films, including total phenolic content and antioxidant capacity. Aside from the control sample prepared only with the alginate, the highest dopamine content was determined in the film with incorporated pumpkin proteins (10.72 mg g−1 dw), while the sample prepared with peanut proteins was richest in betacyanins (175.58 mg betanin g−1 dw).

Effects of the non-covalent interactions between polyphenols and proteins on the formations of the heterocyclic amines in dry heated soybean protein isolate

Soybean proteins are the main component of plant-based meat alternatives in the Chinese market. The effects of non-covalent interactions between polyphenols and proteins on the protein structures, the rest physicochemical properties, and formations of heterocyclic amines (HAs) were examined using a polyphenols-containing soybean protein isolate (SPI) complex as a model to dry heating at 170℃ for 10 min. The results showed that tetrahydro-curcumin had extensive inhibitory effects on the HA formation. In addition, tea polyphenols, grapeseed procyanidins, and dihydromyricetin were also found to have inhibitory effects only on some HAs. Correlation analysis showed that polyphenols altered the secondary structure and steric structure of the protein by interacting with the protein, which affects the HA formation. The results provided theoretical references and a basis for the formation mechanisms of HAs in polyphenol-inhibiting protein foods.

Effects of resveratrol on lipid and protein co-oxidation in fish oil-enriched whey protein isolate emulsions

In this study, the impact of resveratrol (RES) on co-oxidation of lipid and protein in a fish oil-fortified whey protein isolate (WPI) emulsion was investigated. Oil-in-water (O/W) emulsions containing 1% fish oil, 6 mg/mL of WPI and RES (0.08 ~ 2 mM) were oxidatively stressed using a Fenton system at 25 °C for 24 h. The incorporation of RES significantly suppressed lipid oxidation (TBARS) and protein carbonylation. Oxidation-induced decrease on protein sulfhydryl content and surface hydrophobicity were partially attenuated by RES, but protein tryptophan fluorescence was further decreased with the increased concentration of RES. Visualization of protein patterns and MDA-bound protein suggested that RES is capable of inhibiting protein modification induced by secondary products of lipid oxidation. Significant decrease in protein digestibility under oxidizing condition was also mitigated by RES. Our study contributes to the exploration of complicated interactions between oxidized lipids and proteins when phenolic compounds are present.

Aflatoxicosis in Pekin duckling and the effects of treatments with lycopene and silymarin

Background and Aim:

Aflatoxins (AFs) are potent toxic metabolites produced from Aspergillus species. Whose existence in poultry ration leads to drastic economic losses, notably in duck, as the most susceptible poultry species. This study aimed to determine tissue residues of AFs, alterations in selected clinical chemistry variables in serum, mainly during the exposure period, and lycopene and silymarin’s possible roles as herbal treatments against aflatoxicosis in Pekin duckling.

Materials and Methods:

The study used one hundred and twenty one-day-old Pekin ducklings and classified them into four groups comprising 30 ducklings in each group. The control group (G1) ducklings were fed a mycotoxin-free ration, and G2 received a naturally contaminated ration with 30 ppb of AFs. G3 and G4 consumed contaminated rations with AFs with 30 ppb for 2 weeks and were treated with lycopene 100 mg/kg or silymarin 600 mg/kg/food, respectively, for 10 days. Serum activities of alanine transaminase and alkaline phosphatase (ALP), glutamyl transferase, ALP, total protein and albumin creatinine and uric acid concentrations, oxidant/antioxidant parameters (malondialdehyde [MDA], total antioxidant capacity (TAC), glutathione S-transferase (GST), and catalase [CAT]), and hepatic AFs residue were determined. Lycopene and silymarin were used for the treatment of aflatoxicosis for another 10 days.

Results:

Hepatic and kidney parameters were elevated in the AFs intoxicated group and reduced in the lycopene- and silymarin-treated groups. They had elevated MDA and AFs residues with decreased antioxidant parameters (TAC, GST, and CAT) in the AFs group. At the same time, treatment with lycopene or silymarin had reversed the action of AFs on MDA, elevated the hepatic residue, and improved antioxidant activity.

Conclusion:

Lycopene and silymarin, with their potent antioxidant activity, can be used to reverse the harmful effects of AFs on hepatic and kidney tissue.

Attenuation of protein glycation by functional polyphenolics of dragon fruit (Hylocereus polyrhizus); an in vitro and in silico evaluation

Chronic hyperglycemia and oxidative stress promote non-enzymatic glycation that leads to the production of advanced glycation end products (AGEs). AGEs casue significant damage to physiological proteins which result in several complications. The scenario also corresponds to the chronic consumption of a diet rich in AGEs. Despite understanding these mechanisms at the molecular level, the discovery of new drugs for these complications is under progress. Natural compounds might have great therapeutic potential for treating glycative consequences. In view of this, the study aimed to evaluate fruit extracts of Hylocereus polyrhizus towards determining its phenolics and flavonoid contents, as well as assessing it's in vitro antiglycative potential through the use of multistage glycation markers (early, intermediate and end stage products of β-aggregation) in sugar-protein model. In vitro hypoglycemic activity of H. polyrhizus extracts was evaluated through α-amylase and α glucosidase inhibitory activities. In vitro antioxidant potential of the fruit extracts was also examined against different free radical types including DPPH and ABTS. Among the different in vitro assays performed, methanolic and acetone extracts of the fruit, with higher phenolics and flavonoid content, have exerted significant antiglycation and antioxidant activities than other extracts namely aqueous, ethanol, hydro-ethanol, hydro-methanol, and petroleum ether. Ultra-Performance Liquid Chromatography coupled with Electrospray Ionization Mass Spectrometry (UPLC-ESI-MS/MS) analysis was employed to identify active polyphenolics that may be responsible for the antiglycative potential of H. polyrhizus. The analysis revealed some high-profile compounds that have well documented for their therapeutic benefits. Additionally, In silico analysis also showed the possible connection between identified compounds and mechanisms of action. 4- Prenylresveratrol, Vicenin, and Luteolin had observed as effectively interact with target protein in molecular docking analysis. This suggests H. polyrhizus as a good source of anti-glycation and antioxidants that may have potential applications for the treatment and prevention of glycation associated diabetic and aging complications.

Protective effects of phenolics rich extract of ginger against Aflatoxin B1-induced oxidative stress and hepatotoxicity

Aflatoxin B1 (AFB1) is one of the predominant mycotoxin contaminant in food and feed, causing oxidative stress and hepatotoxicity. Ginger phenolics have been reported for its antioxidant potential and hepatoprotective activity. The present study investigated the protective effects of phenolics rich ginger extract (GE) against AFB1 induced oxidative stress and hepatotoxicity, in vitro and in vivo. The phenolic acid profiles of GE showed 6-gingerol and 6-shogaol as predominant components. Pretreatment of HepG2 cells with GE significantly inhibited the production of intracellular reactive oxygen species (ROS), DNA strand break, and cytotoxicity induced by AFB1. A comparable effect was observed in in vivo. Male Wistar rats were orally treated with GE (100 and 250mg/kg) daily, with the administration of AFB 1 (200μg/kg) every alternative day for 28days. Treatment with GE significantly reduced AFB1 induced toxicity on the serum markers of liver damage. In addition, GE also showed significant hepatoprotective effect by reducing the lipid peroxidation and by enhancing the antioxidant enzymes activities. These results combined with liver histopathological observations indicated that GE has potential protective effect against AFB1 induced hepatotoxicity. Additionally, administration of GE up-regulated Nrf2/HO-1 pathway, which further proved the efficiency of GE to inhibit AFB1 induced hepatotoxicity.