The Scavenging of DPPH, Galvinoxyl and ABTS Radicals by Imine Analogs of Resveratrol

Characteristics, antimicrobial capacity, and antioxidant potential of electrospun zein/polyvinyl alcohol nanofibers containing thymoquinone and electrosprayed resveratrol nanoparticles

The aim of the present study was to fabricate, characterize, and evaluate the in vitro antimicrobial and antioxidant properties of zein/polyvinyl alcohol (ZN/PVA) nanofibers containing 2% and 4% of thymoquinone (TQ), either alone or in combination with electrosprayed ZN nanoparticles containing 1% and 2% of resveratrol (RS). According to scanning electron microscopy analysis, the diameter of nanofibers and nanoparticles increased with increasing TQ and RS concentrations, respectively. The molecular interaction between ZN or PVA polymers and TQ or RS was confirmed by Fourier transform infrared spectroscopy. Thermogravimetric analysis showed that the thermal stability of nanofibers did not change with the addition of TQ and RS. Moreover, incorporation of TQ in nanofibers along with RS nanoparticles increased their antibacterial and free radical scavenging activities based on broth dilution and DPPH methods, respectively (p ≤ .05). Escherichia coli O157:H7 (as a Gram-negative pathogenic bacteria) was more resistant to all treatments than Staphylococcus aureus (as a Gram-positive pathogenic bacteria). In addition, the combined use of TQ in nanofibers and RS nanoparticles had antagonistic antibacterial and synergistic antioxidant effects. The best results were obtained with ZN/PVA nanofiber containing 4% TQ and electrosprayed with 2% RS nanoparticles (p ≤ .05). According to the results of the present study, biodegradable ZN/PVA nanofiber containing TQ and electrosprayed with RS nanoparticles can be used as a novel active packaging material in the food industry.

Optimization of the Flavonoid Extraction Process from the Stem and Leaves of Epimedium Brevicornum and Its Effects on Cyclophosphamide-Induced Renal Injury

Cyclophosphamide (CTX) is a broad-spectrum alkylated antitumor drug. It is clinically used in the treatment of a variety of cancers, and renal toxicity is one of the adverse reactions after long-term or repeated use, which not only limits the therapeutic effect of CTX, but also increases the probability of kidney lesions. The total flavonoids of Epimedium stem and leaf (EBF) and Icariin (ICA) are the main medicinal components of Epimedium, and ICA is one of the main active substances in EBF. Modern pharmacological studies have shown that EBF has a variety of biological activities such as improving osteoporosis, promoting cell proliferation, antioxidant and anti-inflammatory properties, etc. However, few studies have been conducted on the nephrotoxicity caused by optimized CTX extraction, and protein-ligand binding has not been involved. This research, through the response surface optimization extraction of EBF, obtained the best extraction conditions: ethanol concentration was 60%, solid-liquid ratio of 25:1, ultrasonic time was about 25 min. Combined with mass spectrometry (MS) analysis, EBF contained ICA, ichopidin A, ichopidin B, ichopidin C, and other components. In this study, we adopted a computational chemistry method called molecular docking, and the results show that Icariin was well bound to the antioxidant target proteins KEAP1 and NRF2, and the anti-inflammatory target proteins COX-2 and NF-κB, with free binding energies of -9.8 kcal/mol, -11.0 kcal/mol, -10.0 kcal/mol, and -8.1 kcal/mol, respectively. To study the protective effect of EBF on the nephrotoxicity of CTX, 40 male Kunming mice (weight 18 ± 22) were injected with CTX (80 mg/kg) for 7 days to establish the nephrotoxicity model and were treated with EBF (50 mg/kg, 100 mg/kg) for 8 days by gavage. After CTX administration, MDA, BUN, Cre, and IL-6 levels in serum increased, MDA increased in kidney, GPT/ALT and IL-6 increased in liver, and IL-6 increased in spleen and was significant ((p < 0.05 or (p < 0.01)). Histopathological observation showed that renal cortex glomerular atrophy necrosis, medullary inflammatory cell infiltration, and other lesions. After administration of EBF, CTX-induced increase in serum level of related indexes was reduced, and MDA in kidney, GPT/ALT and IL-6 in liver, and IL-6 in spleen were increased. At the same time, histopathological findings showed that the necrosis of medullary and corticorenal tubular epithelium was relieved at EBF (50 mg/kg) dose compared with the CTX group, and the glomerular tubular necrosis gradually became normal at EBF (100 mg/kg) dose. Western blot analysis of Keap1 and Nrf2 protein expression in kidney tissue showed that compared with model CTX group, the drug administration group could alleviate the high expression of Keap1 protein and low expression of Nrf2 protein in kidney tissue. Conclusion: After the optimal extraction of total flavonoids from the stems and leaves of Epimedium, the molecular docking technique combined with animal experiments suggested that the effective component of the total flavonoids of Epimedium might activate the Keap1-Nrf2 signaling pathway after treatment to reduce the inflammation and oxidative stress of kidney tissue, so as to reduce kidney damage and improve kidney function. Therefore, EBF may become a new natural protective agent for CTX chemotherapy in the future.

Exploring the chemical composition, medicinal benefits, and antioxidant activity of Plumula nelumbinis essential oil from different habitats in China

Plumula nelumbinis, a widely used traditional Chinese medicine known for its calming and nerve-soothing properties, contains essential oil as a primary component. However, research on P. nelumbinis essential oil (PNEO) is limited. This study aimed to investigate PNEO components, network target analysis, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses, and antioxidant activity of P. nelumbinis from ten different habitats. GC-MS analysis identified 14 compounds in the essential oil, with CP12 (β-Sitosterol) having the highest concentration. Five compounds were identified for the first time in P. nelumbinis, with three of them reported for the first time in the Nelumbo. Network target analysis revealed 185 potential targets for 11 compounds and GO and KEGG enrichment analyses showed that PNEO was mainly located in the plasma membrane and could regulate a variety of molecular functions. KEGG pathway enrichment analysis revealed that the essential oil was primarily enriched in pathways related to cancer and the nervous system. PNEO demonstrated strong antioxidant activity, with N8 (Fujiannanping) showing the highest ABTS scavenging capacity and N7 (Hunanxiangtan) showing the highest DPPH radical scavenging capacity. Cell experiments showed that CP4, CP5 and CP10 had protective effects against H2O2-induced oxidative damage. The study suggests that P. nelumbinis from different regions may have slightly different pharmacological effects due to the presence of unique compounds, and further research is necessary to explore the potential therapeutic benefits of PNEO.

In vivo self-assembled shape-memory polyurethane for minimally invasive delivery and therapy

Advanced elastomers are highly in demand for the fabrication of medical devices for minimally invasive surgery (MIS). Herein, a shape memory and self-healing polyurethane (PCLUSe) composed of semi-crystalline poly(ε-caprolactone) (PCL) segments and interchangeable and antioxidative diselenide bonds was designed and synthesized. The excellent shape memory of PCLUSe contributed to the smooth MIS operation, leading to less surgical wounds than in the case of sternotomy. The diselenide bonds of PCLUSe contributed to the rapid self-healing under 405 nm irradiation within 60 s, and the alleviation of tissue oxidation post injury. After being delivered through a 10 mm diameter trocar onto a beating canine heart by MIS, two shape-recovered PCLUSe films self-assembled (self-healing) into a larger single patch (20 × 10 × 0.2 mm3) under the trigger of laser irradiation in situ, which could efficiently overcome the limited-size problem within MIS and meet a larger treatment area. The diselenide bonds in the PCLUSe cardiac patches protected the myocardium under oxidative stress post myocardial infarction (MI), and significantly maintained the cardiac functions.

Preparation and Characterization of a Novel Artemisia Oil Packaging Film and Its Application in Mango Preservation

In this work, a new food packaging film was synthesized via blending Artemisia oil (AO) into soybean protein isolate (SPI) and gelatin (Gel) for the postharvest storage of mango. The morphological architecture and mechanical properties of the films were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD), and other technologies. The results show that the prepared films had relatively flat surfaces with good mechanical properties. AO enhanced the light-blocking ability of the film, increased the hydrophobicity, and affected the moisture content and water solubility of the film to a certain extent. Furthermore, the antioxidant performance and antifungal (Colletotrichum gloeosporioides) capacity of the films increased with higher AO concentration due to the presence of the active components contained in AO. During mango storage applications, the films showed good freshness retention properties. The above results indicate that SPI-Gel films containing AO have excellent physicochemical and application properties and have great potential in the field of food packaging.

Structural Features of Small Molecule Antioxidants and Strategic Modifications to Improve Potential Bioactivity

This review surveys the major structural features in various groups of small molecules that are considered to be antioxidants, including natural and synthetic compounds alike. Recent advances in the strategic modification of known small molecule antioxidants are also described. The highlight is placed on changing major physicochemical parameters, including log p, bond dissociation energy, ionization potential, and others which result in improved antioxidant activity.

Evaluation of The Antioxidant Capacity of Food Products: Methods, Applications and Limitations

Assays of total antioxidant capacity (TAC) are popular in the analysis of food products. This review presents the most popular assays of TAC and their limitations, databases of TAC of food products, their application in clinical studies, and the effect of processing on the TAC of food. The importance of sample preparation for TAC assays and striking effects of digestion in the gastrointestinal tract on the TAC of food are discussed. Critical opinions on the validity of food TAC assays are considered. It is concluded that TAC methods can be useful as screening assays for food quality control and as low-cost, high-throughput tools used to discover potential antioxidant sources and follow changes in the content of antioxidants during food processing. However, effects revealed by TAC assays should be followed and explained using more specific methods.

Assessment of the Antioxidant Activity of Catechin in Nutraceuticals: Comparison between a Newly Developed Electrochemical Method and Spectrophotometric Methods

The analysis of antioxidants in different foodstuffs has become an active area of research, which has led to many recently developed antioxidant assays. Many antioxidants exhibit inherent electroactivity, and, therefore, the use of electrochemical methods could be a viable approach for evaluating the overall antioxidant activity of a matrix of nutraceuticals without the need for adding reactive species. Green tea is believed to be a healthy beverage due to a number of therapeutic benefits. Catechin, one of its constituents, is an important antioxidant and possesses free radical scavenging abilities. The present paper describes the electrochemical properties of three screen-printed electrodes (SPEs), the first one based on carbon nanotubes (CNTs), the second one based on gold nanoparticles (GNPs) and the third one based on carbon nanotubes and gold nanoparticles (CNTs-GNPs). All three electrodes were modified with the laccase (Lac) enzyme, using glutaraldehyde as a cross-linking agent between the amino groups on the laccase and aldehyde groups of the reticulation agent. As this enzyme is a thermostable catalyst, the performance of the biosensors has been greatly improved. Electro-oxidative properties of catechin were investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV), and these demonstrated that the association of CNTs with GNPs significantly improved the sensitivity and selectivity of the biosensor. The corresponding limit of detection (LOD) was estimated to be 5.6 × 10⁻⁸ M catechin at the CNT-Lac/SPE, 1.3 × 10⁻⁷ M at the GNP-Lac/SPE and 4.9 × 10⁻⁸ M at the CNT-GNP-Lac/SPE. The biosensors were subjected to nutraceutical formulations containing green tea in order to study their catechin content, using CNT-GNP-Lac/SPE, through DPV. Using a paired t-test, the catechin content estimated was in agreement with the manufacturer’s specification. In addition, the relationship between the CNT-GNP-Lac/SPE response at a specific potential and the antioxidant activity of nutraceuticals, as determined by conventional spectrophotometric methods (DPPH, galvinoxyl and ABTS), is discussed in the context of developing a fast biosensor for the relative antioxidant activity quantification.

Cytotoxic and Antioxidant Activities of Imine Analogs of Trans-Resveratrol towards Murine Neuronal N2a Cells

Trans-resveratrol is a natural polyphenol showing numerous biological properties, especially anti-tumoral and antioxidant activity. Among numerous resveratrol derivatives, aza-stilbenes, which bear an imine bound, show interesting biological activities. In the present study, we synthesized a series of imine analogs of trans-resveratrol (seven aza-stilbenes) following an easy and low-cost procedure of green chemistry. The toxicity of synthesized aza-stilbenes, which is currently unknown, was evaluated on murine neuronal N2a cells, comparatively to trans-resveratrol, by considering: cell density evaluated by staining with sulforhodamine 101; esterase activity, which is a criteria of cell viability, by staining with fluorescein diacetate; and transmembrane mitochondrial potential, which is known to decrease during cell death, by staining with DiOC₆(3) using flow cytometry. In addition, the antioxidant activity was quantified with the KRL (Kit Radicaux Libres) assay, the DPPH (2,2′-diphenyl-1-picrylhydrazyl radical) assay and the FRAP (ferric reducing antioxidant power) assay. The PAOT (Pouvoir Antioxidant Total) score was also used. The aza-stilbenes provide different cytotoxic and antioxidant activities, which are either higher or lower than those of trans-resveratrol. Based on their cytotoxic and antioxidant characteristics, all synthesized aza-stilbenes are distinguished from trans-resveratrol.

Antioxidant and cytotoxic activities of selected salicylidene imines: experimental and computational study

Selected salicylidene imines were evaluated for their antioxidant and cytotoxic potentials. Several of them exerted potent scavenging capacity towards ABTS radical and hydrogen peroxide. The insight into the preferable antioxidative mechanism was reached employing density functional theory. In the absence of free radicals, the SPLET mechanism is dominant in polar surroundings, while HAT is prevailing in a non-polar environment. The results obtained for the reactions of the most active compounds with some medically relevant radicals pointed out competition between HAT and SPLET mechanisms. The assessment of their cytotoxic properties revealed inhibition of ER-a human breast adenocarcinoma cells or estrogen-independent prostate cancer cells. Molecular docking study with the cyclooxygenase (COX) 2 enzyme was performed to examine the most probable bioactive conformations and possible interactions between the tested derivatives and COX-2 binding pocket.

Imine-Based Reactive Mesogen and Its Corresponding Exchangeable Liquid Crystal Elastomer

To date, exchangeable liquid crystalline elastomers (xLCEs) have been mainly fabricated by combining conventional LCEs with additional exchangeable functional groups in their networks. While conventional LCEs are frequently made from commercially available aromatic–ester reacting mesogens or from mesogens based on a biphenyl core, such reacting monomers are not optimized to fabricating xLCEs whose bond-exchange reaction is fast and clean cut. Here, we develop a fast synthesis route to produce a new type of reactive mesogen based on an aromatic–imine structure that intrinsically enables a fast and stable bond-exchange reaction in the resulting imine-based xLCE. This new xLCE displays vitrimer plastic-flow behavior, and its bond-exchange activation energy is calculated to be 54 kJ/mol. We also demonstrate that this xLCE is thermally stable to withstand many recycling cycles without visible decay, and its liquid crystallinity is preserved. Finally, we demonstrate the reprogramming and realignment of the mesogen orientation in this xLCE with the realigned xLCE capable of reversible thermal actuation.

1st generation dendrimeric antioxidants containing Meldrum's acid moieties as surface groups

The first small branched architectures decorated with 1,3-dioxane-4,6-dione moieties containing dendrons are synthesized and their antiradical properties are demonstrated.

Imine resveratrol analogs (IRAs): The strong antioxidant that can protect lymphocytes from oxidative damage

Imine resveratrol analogs (IRAs) are promising new agents that can have higher positive effects and, simultaneously, lower negative properties than resveratrol. In this study, three imine hydroxy derivatives (2-((4-hydroxyphenylimino) methyl) phenol [IRA1], 3-((4-hydroxyphenylimino) methyl) phenol [IRA2], and 4-((4-hydroxyphenylimino) methyl) phenol [IRA3]) were prepared and tested in several biological assays. They performed superior to resveratrol in several antioxidant and biological assays, showing high antioxidant capacity and low genotoxicity. Ferric reducing antioxidant power assay (FRAP) and hydroxyl radicals scavenging assay revealed good Fe³⁺ to Fe²⁺ reduction and strong inhibition of hydroxyl radical formation, respectively. High dosage (1 mmol/dm³ ) of IRA2 and IRA3 did not cause genotoxicity in human lymphocytes. Moreover, lymphocytes pretreated with all three IRAs accumulated only very few DNA breaks induced by H₂ O₂ than lymphocytes pretreated with resveratrol. Additionally, the number of detected DNA breaks appearing after removal of damaged DNA bases, 8-oxo-7,8-dihydroguanine (8-oxoG), did not dramatically increase in lymphocytes treated with IRA2. Thus, we concluded that IRAs, especially IRA2, are strong antioxidants with the ability to protect lymphocytes from oxidative damage.

Nanoemulsion-based basil seed gum edible film containing resveratrol and clove essential oil: In vitro antioxidant properties and its effect on oxidative stability and sensory characteristic of camel meat during refrigeration storage

The initial purpose of this study was to compare the in vitro antioxidant interactions between resveratrol (RES) and clove essential oil (CEO) in conventional and nanoemulsion-based basil seed gum (BSG) films. Then, the effects of the best nanoemulsion-based BSG film obtained from in vitro evaluations were determined on oxidative stability and sensory properties of minced camel meat during 20-day storage at 4 °C. The results showed higher in vitro antioxidant activities of nanoemulsion-based BSG films compared to conventional films as well as synergistic effects between RES and CEO. Furthermore, minced camel meat wrapped with nanoemulsion-based BSG film containing RES 4 μg/mL + CEO 10 mg/mL showed better results compared with the control group with the following scores: total carbonyls (0.84 nmol/mg protein), peroxide value (4.03 meq/kg lipid), thiobarbituric acid reactive substance (1.03 mg malondialdehyde/kg), and sensory analysis (overall acceptability: 5.4). The finding of the present study can be applied as a new method in meat and meat products packaging industry.

Anti-Oxidation and Anti-Inflammatory Potency Evaluation of Ferulic Acid Derivatives Obtained through Virtual Screening

Various factors such as ultraviolet rays can cause a continuous threat to our skin, resulting in inflammation or oxidation problems. Ferulic acid (FA), with certain antioxidant and anti-inflammatory properties, is widely used in many cosmetics, even used to treat various diseases in the clinic. In this study, the FA structural skeleton was used to search for FA derivatives. Then, molecular docking, the rule of five, and Veber rules were performed to virtually screen compounds that can bind to proteins with a good drug likeness. DPPH and ABTS were used to evaluate their antioxidant potency and an MTT assay was employed to investigate the toxicities of the compounds, while Griess Reaction System and ELISA were used to judge the concentration variations of NO and different inflammatory factors (TNF-α, IL-1β, and IL-6). Western blotting featured nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein expression levels. The trend of the intracellular changes of reactive oxygen species (ROS) was detected by the DCFH-DA method and fluorescence staining. As a result, we found that the ferulic acid derivative S-52372 not only had certain scavenging effects on free radicals in biochemical experiments, but also prevented inflammation and oxidative stress in LPS-stimulated RAW264.7 cells in the cellular environment; intracellular ROS and inflammatory mediators, including iNOS, COX-2, TNF-α, and IL-6, were also suppressed. In a computer prediction, S-52372 owned better water solubility and lower toxicity than FA. This compound deserves further research to find an ideal FA derivative.

Cardioprotective Effect of Maternal Supplementation with Resveratrol on Toxicity Induced by Doxorubicin in Offspring Cardiomyocytes

Fundamento

A doxorrubicina (DOX) é frequentemente usada para tratar muitos tipos de cânceres, apesar da cardiotoxicidade dose-dependente. Como alternativa, o resveratrol é um polifenol que tem demonstrado efeitos cardioprotetores em vários modelos de disfunção cardíaca.

Objetivo

Este estudo investigou se o tratamento com resveratrol em ratas gestantes protege contra toxicidade induzida por doxorrubicina em cardiomiócitos da ninhada.

Métodos

Ratas Wistar (n-8) receberam sresveratrol como suplemento alimentar durante a gestação. No nascimento da ninhada, os corações (9-11) foram usados para se obter a cultura primária de cardiomiócitos. A cardiotoxicidade induzida por DOX e os efeitos da suplementação com resveratrol foram avaliados por marcadores de stress oxidativo, tais como oxidação da diclorofluoresceína diacetato, diminuição da atividade de enzimas antioxidantes, e oxidação do teor total de grupos sulfidrila, além da avaliação da viabilidade celular, geração de danos ao DNA, bem como a resposta de reparo aos danos ao DNA. Um valor de p <0,05 foi considerado estatisticamente significativo.

Resultados

Os cardiomiócitos de neonatos de ratas que receberam suplemento resveratrol apresentaram um aumento (p <0,01) na viabilidade das células, e diminuição (p <0,0001) de células apoptóticas/necróticas após o tratamento com DOX, o que está correlacionado às atividades de enzimas antioxidantes e produção de diclorofluoresceína. Além disso, o resveratrol protegeu os cardiomiócitos de danos ao DNA induzidos por DOX, apresentando uma diminuição (p <0,05) nas quebras de DNA induzidas por stress oxidativo, avaliadas pela atividade de enzimas reparadoras do DNA endonuclease III e formamidopirimidina glicosilase. A suplementação com resveratrol aumentou (p <0,05) a expressão da proteína reparadora Sirt6 nos cardiomiócitos dos filhotes.

Conclusão

Essa pesquisa indica que a suplementação com resveratrol durante o período gestacional tem um efeito cardioprotetor no coração da ninhada contra a toxicidade induzida por DOX, o que pode se dever a sua função antioxidante, e o aumento na resposta de danos ao DNA.

Myeloperoxidase Inhibitory and Antioxidant Activities of (E)-2-Hydroxy-α-aminocinnamic Acids Obtained through Microwave-Assisted Synthesis

Myeloperoxidase (MPO) is an enzyme present in human neutrophils, whose main role is to provide defenses against invading pathogens. However, highly reactive oxygen species (ROS), such as HOCl, are generated from MPO activity, leading to chronic diseases. Herein, we report the microwave-assisted synthesis of a new series of stable (E)-(2-hydroxy)-α-aminocinnamic acids, in good yields, which are structurally analogous to the natural products (Z)-2-hydroxycinnamic acids. The radical scavenging activity (RSA), MPO inhibitory activity and cytotoxicity of the reported compounds were evaluated. The hydroxy derivatives showed the most potent RSA, reducing the presence of DPPH and ABTS radicals by 77% at 0.32 mM and 100% at 0.04 mM, respectively. Their mechanism of action was modeled with BDE_OH, IP and ΔE_H-L theoretical calculations at the B3LYP/6 − 31 + G(d,p) level. Compounds showed in vitro inhibitory activity of MPO with IC₅₀ values comparable to indomethacin and 5-ASA, but cytotoxicities below 15% at 100–200 µM. Docking calculations revealed that they reach the amino acid residues present in the distal cavity of the MPO active site, where both the amino and carboxylic acid groups of the α-aminopropenoic acid arm are structural requirements for anchoring. (E)-2-hydroxy-α-aminocinnamic acids have been synthesized for the first time with a reliable method and their antioxidant properties demonstrated.

Development and in vitro evaluation of novel nutraceutical formulations composed of Limosilactobacillus fermentum, quercetin and/or resveratrol

This study developed and carried out an in vitro evaluation of nutraceutical formulations composed of potentially probiotic Limosilactobacillus fermentum (L. fermentum 139, L. fermentum 263 or L. fermentum 296), quercetin and/or resveratrol. L. fermentum strains had counts of >9 log CFU/g and contents of QUE and RES of >200 µg/mg in formulations after freeze-drying. Formulations with QUE and RES protected L. fermentum during exposure to in vitro acidic stomach conditions. L. fermentum strains had counts of >6 log CFU/g on day 60 and/or 90 of refrigeration storage. Contents of QUE (>29%) and RES (>50%) in formulations were potentially bioaccessible. Higher counts of L. fermentum and higher contents of QUE and RES were found in formulations stored under refrigerated rather than under room temperature. All nutraceutical formulations had antioxidant properties. Combinations of probiotic L. fermentum and QUE and/or RES should be an innovative strategy to develop added-value nutraceutical formulations.

Natural Antioxidants: A Review of Studies on Human and Animal Coronavirus

The outbreaks of viruses with wide spread and mortality in the world population have motivated the research for new therapeutic approaches. There are several viruses that cause a biochemical imbalance in the infected cell resulting in oxidative stress. These effects may be associated with the development of pathologies and worsening of symptoms. Therefore, this review is aimed at discussing natural compounds with both antioxidant and antiviral activities, specifically against coronavirus infection, in an attempt to contribute to global researches for discovering effective therapeutic agents in the treatment of coronavirus infection and its severe clinical complications. The contribution of the possible action of these compounds on metabolic modulation associated with antiviral properties, in addition to other mechanisms of action, is presented.

Structural basis of the anti-ageing effects of polyphenolics: mitigation of oxidative stress

Ageing, and particularly the onset of age-related diseases, is associated with tissue dysfunction and macromolecular damage, some of which can be attributed to accumulation of oxidative damage. Polyphenolic natural products such as stilbenoids, flavonoids and chalcones have been shown to be effective at ameliorating several age-related phenotypes, including oxidative stress, inflammation, impaired proteostasis and cellular senescence, both in vitro and in vivo. Here we aim to identify the structural basis underlying the pharmacology of polyphenols towards ROS and related biochemical pathways involved in age-related disease. We compile and describe SAR trends across different polyphenol chemotypes including stilbenoids, flavonoids and chalcones, review their different molecular targets and indications, and identify common structural ground between chemotypes and mechanisms of action. In particular, we focus on the structural requirements for the direct scavenging of reactive oxygen/nitrogen species such as radicals as well as coordination of a broader antioxidant response. We further suggest that it is important to consider multiple (rather than single) biological activities when identifying and developing new medicinal chemistry entities with utility in modulating complex biological properties such as cell ageing.

Aza- and Azo-Stilbenes: Bio-Isosteric Analogs of Resveratrol

Several series of natural polyphenols are described for their biological and therapeutic potential. Natural stilbenoid polyphenols, such as trans-resveratrol, pterostilbene and piceatannol are well-known for their numerous biological activities. However, their moderate bio-availabilities, especially for trans-resveratrol, prompted numerous research groups to investigate innovative and relevant synthetic resveratrol derivatives. This review is focused on isosteric resveratrol analogs aza-stilbenes and azo-stilbenes in which the C=C bond between both aromatic rings was replaced with C=N or N=N bonds, respectively. In each series, synthetic ways will be displayed, and structural sights will be highlighted and compared with those of resveratrol. The biological activities of some of these molecules will be presented as well as their potential therapeutic applications. In some cases, structure-activity relationships will be discussed.

Effects of Salt Stimulation on Lunasin Accumulation and Activity during Soybean Germination

Lunasin, a bioactive peptide, was originally found in soybeans, and it has exhibited multiple biological functions. On the basis of previous studies, salt stress was found able to induce changes in many polypeptides and translatable mRNA levels in plants. Salt stress was applied to soybean germination, with water treatment as a control group, to evaluate the effects of salt stimulation on lunasin accumulation and activity during soybean germination. Lunasin content gradually increased in the control group during germination, reached the highest level after six hours of imbibition, and then slowly decreased. Under salt exposure, lunasin content showed a similar trend to that of the control group. The lunasin content in salt-treated soybean was significantly higher than that in the control group. Lunasin peptide was purified from soybean after six hours of imbibition and it was then used for function evaluation. Purified lunasin from salt-stress-germinated soybean (6 h-LSGS) exhibited stronger antioxidant activity than lunasin from water-treatment-germinated soybean (6 h-LWGS) and soybean seed without imbibition (DRY). The 6 h-LSGS presented anti-inflammatory activity on LPS-induced macrophage cells (p < 0.05) by suppressing the release of nitric oxide (NO) and proinflammatory cytokines, including IL-1 and IL-6. The gene expression of NOS, IL-1, IL-6, and TNF-α was significantly inhibited by 6 h-LSGS. Further, 6 h-LSGS exhibited superior antiproliferation activity on human breast-cancer cells MDA-MB-231 when compared to 6 h-LWGS and DRY. Overall, this study offers a feasible elicitation strategy for enhancing lunasin accumulation and its properties in soybean for possible use in functional food.

In Vitro and In Vivo Antioxidant Activity of the New Magnetic-Cerium Oxide Nanoconjugates

BACKGROUND

Cerium oxide nanoparticles present the mimetic activity of superoxide dismutase, being able to inactivate the excess of reactive oxygen species (ROS) correlated with a large number of pathologies, such as stents restenosis and the occurrence of genetic mutations that can cause cancer. This study presents the synthesis and biological characterisation of nanoconjugates based on nanoparticles of iron oxide interconnected with cerium oxide conjugates.

METHODS

The synthesis of magnetite-nanoceria nanoconjugates has been done in several stages, where the key to the process is the coating of nanoparticles with polyethyleneimine and its chemical activation-reticulation with glutaraldehyde. The nanoconjugates are characterised by several techniques, and the antioxidant activity was evaluated in vitro and in vivo.

RESULTS

Iron oxide nanoparticles interconnected with cerium oxide nanoparticles were obtained, having an average diameter of 8 nm. Nanoconjugates prove to possess superparamagnetic properties and the saturation magnetisation varies with the addition of diamagnetic components in the system, remaining within the limits of biomedical applications. In vitro free-radical scavenging properties of nanoceria are improved after the coating of nanoparticles with polyethylenimine and conjugation with magnetite nanoparticles. In vivo studies reveal increased antioxidant activity in all organs and fluids collected from mice, which demonstrates the ability of the nanoconjugates to reduce oxidative stress.

CONCLUSION

Nanoconjugates possess magnetic properties, being able to scavenge free radicals, reducing the oxidative stress. The combination of the two properties mentioned above makes them excellent candidates for theranostic applications.

Evaluation of the Synergistic Antioxidant Effect of Resveratrol and Zataria multiflora Boiss Essential Oil in Sodium Alginate Bioactive Films

BACKGROUND

Biodegradable films are appropriate alternatives to synthetic polymers due to their potential to enhance food safety and their function as a carrier for wide a range of food additives especially natural antioxidants.

OBJECTIVE

The aim of this study was to compare the potential antioxidant activities of sodium alginate films containing resveratrol (RES) alone and in combination with Zataria multiflora essential oil (ZEO) using an in vitro model.

METHODS

At first, the major chemical compositions of ZEO were evaluated by GC/MS. Then, the amount of phenolic compounds of sodium alginate films were evaluated by total phenolic contents assay and antioxidant activities of films were evaluated by 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays. Finally, the concentrations of ZEO and RES which showed better antioxidant activities in sodium alginate films were incorporated to films in combination forms to evaluate their synergistic effects.

RESULTS

According to gas chromatography-mass spectrometry (GC/MS) analysis, 35 compounds of ZEO were identified and Thymol (37.94%), p-Cymene (9.50%) and 3-Carene (4.98%) were the most important compounds of essential oil, respectively. The results of the radical scavenging evaluations, showed better antioxidant activities of the films containing RES than the films containing ZEO and Butylated hydroxytoluene (BHT). Also, the combined uses of ZEO and RES into alginate films had the synergistic effects (P<0.05).

CONCLUSION

Therefore, it can be concluded that alginate films incorporated with the combination of ZEO and RES is the appropriate option to postpone the oxidative reactions and can be used as natural antioxidant in the food packaging industry.

Carbon-Carbon Double Bond and Resorcinol in Resveratrol and Its Analogues: What Is the Characteristic Structure in Quenching Singlet Oxygen?

Stilbenes, particularly resveratrol and resveratrol dimers, could effectively quench singlet oxygen (¹O₂). It was reported that both resorcinol and carbon-carbon double bond quenching ¹O₂ can participate in the mechanism. However, it is still not clear which structure plays a dominant role in quenching ¹O₂. To investigate the characteristic structure in the mechanism of quenching ¹O₂, the resveratrol, pterostilbene and piceatannol quenching ¹O₂ abilities were compared by UHPLC-QTOF-MS² and UHPLC-QQQ-MS². Results showed that catechol, carbon-carbon double bond and resorcinol participated in the quenching of ¹O₂. Catechol ring plays a leading role in the mechanism, and the contribution of the structures in quenching ¹O₂ activity are as follows: catechol ring > carbon-carbon double bond > resorcinol ring, which is supported by the calculation of energy. Our findings will contribute to the future screening of stilbenes with higher activity, and those stilbenes may have great therapeutic potential in ¹O₂-mediated diseases.

Molecular docking analysis of imine stilbene analogs and evaluation of their anti-aging activity using yeast and mammalian cell models

The NAD⁺-dependent histone deacetylase SIRT1 was shown to be associated with aging and longevity. A stilbene, resveratrol (RV) was shown to exert anti-aging activity by stimulating the SIRT1 activity. However, the utility of RV is limited by its low bioavailability and structural instability. It is thus envisaged to test imine stilbene (IMS) analogs of RV for their potential anti-aging activity. In the present study, molecular docking analysis of five IMS analogs (3a, 3b, 3c, 3d and 3e) against the SIRT1 protein has been carried out. All the five IMS analogs displayed enhanced binding affinity towards SIRT1; three out of five IMS analogs (3a, 3 b, 3e) showed significantly higher affinity with lower binding energies (-9.58, -9.54, and -9.82 kcal mol^-1) than RV (-8.11 kcal mol^-1). Further, experimental validation of anti-aging activity was performed by measuring the chronological life span in vitro using yeast and cellular replicative senescence (CRS) in mammalian cell line models. All IMS analogs extended the chronological life span in yeast as compared to untreated cells as well as RV treated cells. Enhanced anti-aging activity was also observed in an analogous mammalian cell line model upon treatment with either RV or IMS analogs. The results thus suggest that most of the IMS analogs tested may serve as potent drug lead molecules with anti-aging activity.

Expression of Bioactive Lunasin Peptide in Transgenic Rice Grains for the Application in Functional Food

Lunasin, a bioactive peptide initially isolated from soybean, has anticancer, anti-inflammatory, and antioxidant activity. Due its great application value, lunasin seems to be a candidate gene in improving the nutritional value of crops. In this study, lunasin was inserted into the rice genome to evaluate whether it was feasible to express lunasin using the rice expression system and improve the bioactivity of protein in rice for our needs. We generatedlunasin-overexpressing rice lines, and chose three independent transgenic rice lines for further study. The lunasin content in trans-lunasin rice detected by UPLC-MS/MS was 1.01 × 10⁻³ g·kg⁻¹ dry rice flour with grease removal in the lunasin extracts. The antioxidant efficacy of LET (lunasin-enriched fraction from trans-lunasin rice) and PEW (peptide-enriched fraction from wild type rice) was compared. Due to the presence of lunasin, LET showed higher (p < 0.05) antioxidant activity than PEW. LET exhibited high DPPH radical scavenging activity (IC₅₀ value, 8 g·L⁻¹), strong ABTS⁺ radical scavenging activity (IC₅₀ value, 1.18 g·L⁻¹), and great oxygen radical scavenging activity (170 μmol·L⁻¹ Trolox equivalents when the concentration reached 4 g·L⁻¹). Moreover, LET presented significantly higher (p < 0.05) anti-inflammatory activity on macrophage cells, and the NO production and the release of pro-inflammatory cytokines (IL-6, MCP1, and TNF-α) were significantly inhibited by LET. However, because of the low purity, LET showed weaker antioxidant and anti-inflammatory activity when compared to the Lunasin standard. These results suggested that it is feasible to use the rice expression system to express the exogenous lunasin in rice, and lunasin-overexpressing rice seems to be a candidate resource for application in functional food. Rice rich in lunasin is beneficial for human health, and could be used as a functional food in the diets of cancer and obese patients in the future.

E-Configuration Improves Antioxidant and Cytoprotective Capacities of Resveratrols

The antioxidant and cytoprotective capacities of E-resveratrol and Z-resveratrol were compared using chemical and cellular assays. Chemical assays revealed that the two isomers were dose-dependently active in •O₂^--scavenging, ferric reducing antioxidant power (FRAP), Cu²⁺-reducing antioxidant capacity (CUPRAC), 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide radical (PTIO•)-scavenging (pH 7.4 and pH 4.5), and 1,1-diphenyl-2-picryl-hydrazyl (DPPH•)-scavenging assays. The cellular assay indicated that the two isomers could also increase cell viabilities. However, quantitative analyses suggested that E-resveratrol exhibited stronger effects than Z-resveratrol in all chemical and cellular assays. Finally, the conformations of E-resveratrol and Z-resveratrol were analyzed. It can be concluded that both E-resveratrol and Z-resveratrol can promote redox-related pathways to exhibit antioxidant action and consequently protect bone marrow-derived mesenchymal stem cells (bmMSCs) from oxidative damage. These pathways include electron transfer (ET) and H⁺-transfer, and likely include hydrogen atom transfer (HAT). The E-configuration, however, improves antioxidant and cytoprotective capacities of resveratrols. The detrimental effect of the Z-configuration may be attributed to the non-planar preferential conformation, where two dihedral angles block the extension of the conjugative system.

Resveratrol analogues like piceatannol are potent antioxidants as quantitatively demonstrated through the high scavenging ability against reactive oxygen species and methyl radical

Resveratrol (RSV) analogues have attracted much attention because of the expected health functions including antioxidant activities. We have carried out a quantitative determination of the scavenging abilities of six trans-RSV analogues against various reactive oxygen species and methyl radical (hydroxyl radical, superoxide, alkoxyl radical, peroxyl radical, methyl radical, and singlet oxygen). RSV analogues are in general more potent scavenger than the parent RSV. Furthermore, piceatannol (PIC) having two OH groups in the ortho position of resveratrol was found to show 11 times higher scavenging ability against peroxyl radical than parent resveratrol. With the aid of previous theoretical studies, the enhanced antioxidant ability was interpreted based on the effects of substituent that modifies the original resveratrol structure and function.

Synthesis and Free Radical Scavenging Activity of New Hydroxybenzylidene Hydrazines

Hydroxybenzylidene hydrazines exhibit a wide spectrum of biological activities. Here, we report synthesis and free radical scavenging activity of nine new N-(hydroxybenzylidene)-N′-[2,6-dinitro-4-(trifluoromethyl)]phenylhydrazines. The chemical structures of these compounds were confirmed by ¹H-NMR, ¹³C-NMR, ¹⁹F-NMR, IR spectroscopy, LC-MS, and elemental analysis. The prepared compounds were tested for their activity to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH), galvinoxyl radical (GOR), and 2,2′-azino-bis(3-ethylbenzothiazoline)-6-sulphonic acid (ABTS) radicals. The free radical scavenging activity expressed as SC₅₀ values of these compounds varied in a wide range, from a strong to no radical scavenging effect. The most effective radical scavengers were hydroxybenzylidene hydrazines containing three hydroxyl groups in the benzylidene part of their molecules. The prepared compounds were also tested for their activity to inhibit photosynthetic electron transport in spinach chloroplasts. IC₅₀ values of these compounds varied in wide range, from an intermediate to no inhibitory effect.

Growth-Inhibiting Activity of Resveratrol Imine Analogs on Tumor Cells In Vitro

Although resveratrol exerts manifold antitumorigenic effects in vitro, its efficacy against malignancies in vivo seems limited. This has been increasingly recognized in recent years and has prompted scientists to search for structurally related compounds with more promising anticarcinogenic and/or pharmacokinetic properties. A class of structurally modified resveratrol derivatives, so-called resveratrol imine analogs (IRA's), might meet these requirements. Therefore, the biological activity of five of these compounds was examined and compared to that of resveratrol. Firstly, the antiproliferative potency of all five IRA's was investigated using the p53 wildtype-carrying colorectal carcinoma cell line HCT-116wt. Then, using the former and a panel of various other tumor cell lines (including the p53 knockout variant HCT-116p53-/-), the growth-inhibiting and cell cycle-disturbing effects of the most potent IRA (IRA 5, 2-[[(2-hydroxyphenyl)methylene]amino]-phenol) were studied as was its influence on cyclooxygenase-2 expression and activity. Finally, rat liver microsomes were used to determine the metabolic stability of that compound. IRA 5 was clearly the most potent compound in HCT-116wt cells, with an unusually high IC50-value of 0.6 μM. However, in the other five cell lines used, the antiproliferative activity was mostly similar to resveratrol and the effects on the cell cycle were heterogeneous. Although all cell lines were affected by treatment with IRA 5, cells expressing functional p53 seemed to react more sensitively, suggesting that this protein plays a modulating role in the induction of IRA 5-mediated biological effects. Lastly, IRA 5 led to contradictory effects on cyclooxygenase-2 expression and activity and was less glucuronidated than resveratrol. As IRA 5 is approximately 50 times more toxic towards HCT-116wt cells, exerts different effects on the cyclooxygenase-2 and is metabolized to a lesser extent, it shows certain advantages over resveratrol and could therefore serve as basis for additional chemical modifications, potentially yielding compounds with more favorable biological and pharmacokinetic features.

Ageing-Associated Oxidative Stress and Inflammation Are Alleviated by Products from Grapes

Advanced age is associated with increased incidence of a variety of chronic disease states which share oxidative stress and inflammation as causative role players. Furthermore, data point to a role for both cumulative oxidative stress and low grade inflammation in the normal ageing process, independently of disease. Therefore, arguably the best route with which to address premature ageing, as well as age-associated diseases such as diabetes, cardiovascular disease, and dementia, is preventative medicine aimed at modulation of these two responses, which are intricately interlinked. In this review, we provide a detailed account of the literature on the communication of these systems in the context of ageing, but with inclusion of relevant data obtained in other models. In doing so, we attempted to more clearly elucidate or identify the most probable cellular or molecular targets for preventative intervention. In addition, given the absence of a clear pharmaceutical solution in this context, together with the ever-increasing consumer bias for natural medicine, we provide an overview of the literature on grape (Vitis vinifera) derived products, for which beneficial effects are consistently reported in the context of both oxidative stress and inflammation.