Antioxidant synergism of green tea polyphenols with α-tocopherol and l-ascorbic acid in SDS micelles

A colorimetric sensor array based on peroxidase activity nanozyme for the highly efficient differential sensing of tea polyphenols and Tieguanyin adulteration

Tieguanyin (TGY) is one of top ten famous teas in China, but in the process of brand building there is the phenomenon of falsehood, thus harming the interests of consumers. To solve theadulterate problem of TGY, a colorimetric sensor array (CSA) based onperoxidase activity of nanozyme was constructed. Nanozymes can catalyze 3,3',5,5'-tetramethylbenzidine (TMB) to 3,3',5,5'-tetramethyl -[1,1'-bis(cyclohexyl)]-2,2',5,5'-tetraene-4,4'-diimine (oxTMB), while the tea polyphenols (TPs) can inhibit this process, and the degree of inhibition varies significantly with the reaction time. We selected two nanozymesand three reaction time points to construct CSA. It can successfully distinguish TPsin TGY. The discriminative analysiscan achieve: (1)distinction between TGY and adulterated tea, (2)discrimination of TGY in various seasons and seasonal adulteration in different degrees. The method constructed in this work is promising for both the class and quality differentiation of TGY and other teas with TPs as the main activity.

Green tea polyphenols improved the physicochemical stability of mango powder during storage

In this study, the physiochemical characters including moisture content variation, pH, total soluble solids (TSS), color, ascorbic acid content, total polyphenols, and antioxidant activities of mango powder fortified with green tea polyphenols (GTP) were investigated during storage for 90 d. Our results indicated stable colors of mango powder were found after GTP addition. GTP also inhibited the destruction of ascorbic acid during processing, and decreased its degradation rate during the whole storage. The total polyphenols of mango powder stored at 4 ℃ and room temperature decreased by 37.85% and 51.79%, respectively. After addition with GTP, the total polyphenols decreased only by 7.89%, and 13.31%, respectively. The antioxidant activities rose by 1.6 to 4.6-fold after GTP addition, and it decreased at a slower rate compared to that of unfortified mango powder. Correlation analysis indicated that EGCG might be the main substance that retain the physiochemical stability of mango powder.

Novel nutritionally-enriched gummy jelly infused with nipa palm vinegar powder and nipa palm syrup as functional food ingredients

The objective of this research was to develop a nutritionally-enriched gummy jelly product incorporating nipa palm vinegar powder (NPVp; a nutrients-rich vinegar) and nipa palm syrup (NPS), a nutrients-rich sweetener with a low glycemic index. A gummy jelly product was developed based on sensory acceptance tests. The water activity and the moisture content of the final product were within the acceptable range for preservation under ambient conditions. The final product had a total phenolic content of 861 μg gallic acid equivalent (GAE) per g and an antioxidant activity (2,2-diphenyl-1-picrylhydrazyl (DPPH) inhibition) of 72.7 %. The final product had the following nutritional attributes (per 100 g dry mass): 319.7 kcal of energy, 8.8 g protein, 0.2 g fats, 70.6 g carbohydrates, 59.9 g total sugars, 0.7 g of total dietary fibers, 34.6 mg calcium, 0.3 mg iron, 168.0 mg sodium, and 774.7 mg vitamin C. The in vitro glycemic index of the product was 27.4. Based on their nutrients-content, NPVp and NPS were suitable for use in other functional food products.

The Profile of Polyphenolic Compounds, Contents of Total Phenolics and Flavonoids, and Antioxidant and Antimicrobial Properties of Bee Products

This study aimed to characterize bee products (bee bread, bee pollen, beeswax, and multiflorous honey) with the profile of phenolic compounds, total phenolic (TPC) and flavonoid (TFC) contents, and antioxidant and microbiological properties. The TP and TF contents could be ordered as follows: bee pollen > bee bread > beeswax > honey. The UPLC-PDA-MS/MS analysis allowed identifying 20 polyphenols. Sinapic acid dominated in bee pollen, gallic acid in the bee bread and honey, while pinobanksin was the major compound of beeswax. The data showed that bee pollen and bee bread had a stronger antioxidant potential than honey and beeswax. Moreover, the antibacterial activity of the bee products was studied using 14 bacterial strains. Bee bread's and bee pollen's antimicrobial activity was higher towards Gram-negative strains. In comparison, honey was more potent in inhibiting Gram-positive bacteria. Our study indicates that bee products may represent valuable sources of bioactive compounds offering functional properties.

Advances in the control of lipid peroxidation in oil-in-water emulsions: kinetic approaches†

Large efforts have been, and still are, devoted to minimize the harmful effects of lipid peroxidation. Much of the early work focused in understanding both the lipid oxidation mechanisms and the action of antioxidants in bulk solution. However, food-grade oils are mostly present in the form of oil-in-water emulsions, bringing up an increasing complexity because of the three-dimensional interfacial region. This review presents an overview of the kinetic approaches employed in controlling the oxidative stability of edible oil-in-water emulsions and of the main outcomes, with particular emphasis on the role of antioxidants and on the kinetics of the inhibition reaction. Application of physical-organic chemistry methods, such as the pseudophase models to investigate antioxidant partitioning, constitute a remarkable example on how kinetic methodologies contribute to model chemical reactivity in multiphasic systems and to rationalize the role of interfaces, opening new opportunities for designing novel antioxidants with tailored properties and new prospects for modulating environmental conditions in attempting to optimize their efficiency. Here we will summarize the main kinetic features of the inhibition reaction and will discuss on the main factors affecting its rate, including the determination of antioxidant efficiencies from kinetic profiles, structure-reactivity relationships, partitioning of antioxidants and concentration effects.

Tea and coffee polyphenols and their biological properties based on the latest in vitro investigations

Tea and coffee contain numerous polyphenolic compounds that exhibit health-promoting properties for humans, including antioxidant and neuroprotective properties, and can also take part in the treatment of covid-19 and improve fertility. This review, presents the activity of polyphenols found in different types of tea and coffee and describes the effects of tea fermentation and coffee roasting on their polyphenol composition and antioxidant properties. Polyphenol oxidase activity is reduced in the fermentation process; therefore black tea contains significantly less polyphenolic compounds compared to green and white tea. Epigallocatechin-3-gallate - a polyphenol from tea - effectively has been shown to inhibit the activity of SARS-CoV-2 as it blocked binding of coronavirus 2 to human angiotensin converting enzyme 2, decreased the expression of inflammatory factors in the blood, including tumor necrosis factor-α and interleukin-6, and significantly increased the overall fertilization efficiency in animals. Coffee roasting process influences both the content of polyphenols and the oxidative activity. The lowest levels of active compounds such as caffeine, chlorogenic acid and coffee acids are identified in roasted coffee beans. On the other hand, light coffee and green coffee show the strongest cytotoxic potential and antioxidant properties, and thus the greatest ability to decrease apoptosis by stopping the cell cycle in the S phase. Proteins, such as components of milk, can strongly bind/interact with phenolic compounds (especially, the CGAs) contain in coffee, which may explain the negative influence of milk on its antioxidant properties. Coffee polyphenols have also antiproliferative and antiesterase activities, which may be important in prevention of cancer and neurodegenerative disorders, respectively. In this review, biological properties of tea and coffee polyphenols, observed mainly in in vitro studies have been described. Based on these findings, future directions of the research works on these compounds have been suggested.

Tea and coffee polyphenols and their biological properties based on the latest in vitro investigations

Tea and coffee contain numerous polyphenolic compounds that exhibit health-promoting properties for humans, including antioxidant and neuroprotective properties, and can also take part in the treatment of covid-19 and improve fertility. This review, presents the activity of polyphenols found in different types of tea and coffee and describes the effects of tea fermentation and coffee roasting on their polyphenol composition and antioxidant properties. Polyphenol oxidase activity is reduced in the fermentation process; therefore black tea contains significantly less polyphenolic compounds compared to green and white tea. Epigallocatechin-3-gallate - a polyphenol from tea - effectively has been shown to inhibit the activity of SARS-CoV-2 as it blocked binding of coronavirus 2 to human angiotensin converting enzyme 2, decreased the expression of inflammatory factors in the blood, including tumor necrosis factor-α and interleukin-6, and significantly increased the overall fertilization efficiency in animals. Coffee roasting process influences both the content of polyphenols and the oxidative activity. The lowest levels of active compounds such as caffeine, chlorogenic acid and coffee acids are identified in roasted coffee beans. On the other hand, light coffee and green coffee show the strongest cytotoxic potential and antioxidant properties, and thus the greatest ability to decrease apoptosis by stopping the cell cycle in the S phase. Proteins, such as components of milk, can strongly bind/interact with phenolic compounds (especially, the CGAs) contain in coffee, which may explain the negative influence of milk on its antioxidant properties. Coffee polyphenols have also antiproliferative and antiesterase activities, which may be important in prevention of cancer and neurodegenerative disorders, respectively. In this review, biological properties of tea and coffee polyphenols, observed mainly in in vitro studies have been described. Based on these findings, future directions of the research works on these compounds have been suggested.

Green Extraction of Bioactive Compounds from Plant Biomass and Their Application in Meat as Natural Antioxidant

Plant extracts are rich in various bioactive compounds exerting antioxidants effects, such as phenolics, catechins, flavonoids, quercetin, anthocyanin, tocopherol, rutin, chlorogenic acid, lycopene, caffeic acid, ferulic acid, p-coumaric acid, vitamin C, protocatechuic acid, vitamin E, carotenoids, β-carotene, myricetin, kaempferol, carnosine, zeaxanthin, sesamol, rosmarinic acid, carnosic acid, and carnosol. The extraction processing protocols such as solvent, time, temperature, and plant powder should be optimized to obtain the optimum yield with the maximum concentration of active ingredients. The application of novel green extraction technologies has improved extraction yields with a high concentration of active compounds, heat-labile compounds at a lower environmental cost, in a short duration, and with efficient utilization of the solvent. The application of various combinations of extraction technologies has proved to exert a synergistic effect or to act as an adjunct. There is a need for proper identification, segregation, and purification of the active ingredients in plant extracts for their efficient utilization in the meat industry, as natural antioxidants. The present review has critically analyzed the conventional and green extraction technologies in extracting bioactive compounds from plant biomass and their utilization in meat as natural antioxidants.

Cellular Defensive Mechanisms of Tea Polyphenols: Structure-Activity Relationship

Tea is particularly rich in polyphenols, including catechins and theaflavins, thearubigins, flavonols, and phenolic acids, which are believed to contribute to the health benefits of tea. The health-promoting effects of tea polyphenols are believed to be related to their cellular defensive properties. This review is intended to briefly summarize the relationship between the chemical structures of tea polyphenols and their biological activities. Tea polyphenols appear as direct antioxidants by scavenging reactive oxygen/nitrogen species; chelating transition metals; and inhibiting lipid, protein, and DNA oxidations. They also act directly by suppressing “pro-oxidant” enzymes, inducing endogenous antioxidants, and cooperating with vitamins. Moreover, tea polyphenols regulate cellular signaling transduction pathways, importantly contributing to the prevention of chronic diseases and the promotion of physiological functions. Apparently, the features in the chemical structures of tea polyphenols are closely associated with their antioxidant potentials.

Current State of Knowledge on the Antioxidant Effects and Mechanisms of Action of Polyphenolic Compounds

Quality-of-life improvements have resulted in increasing attention being paid to research on antiaging and antioxidation. Polyphenols are natural antioxidants with excellent biological activities, such as antioxidation and scavenging of free radicals and antiviral activity. Abundant availability and low toxicity of polyphenols have attracted the attention of researchers. In this paper, the antioxidant activities of flavonoids, phenolic acids, stilbenes and lignan polyphenols are analyzed, the corresponding antioxidant mechanisms are investigated, and the antioxidant effects of polyphenols are systematically reviewed. Thus, an effective reference based on the recent literature is compiled for the study of the antioxidant mechanisms of polyphenols that provides a significant theoretical basis for the development of products that are components of polyphenols.

Novel strategy of natural antioxidant nutrition quality evaluation in food: Oxidation resistance mechanism and synergistic effects investigation

Effective evaluation methods for assessing the nutritional quality of foods that eliminate free radicals (i.e., foods that are classified as antioxidants) have long attracted the attention of scientists and the populace. In this case, constructing a corresponding photoelectrochemical sensor that has the advantages of being intuitive, rapid, and capable of accurate assessment for global antioxidant capacity is of profound significance. In this study, a novel g-C₃N₄/NiS/TiO₂ photoelectric sensitive platform was constructed and afforded the possibility of a synergistic/antagonistic effect for estimating intrinsic antioxidant ingredients in food. Further investigation revealed that the internal influences of the compound structure, such as the redox potential and type of groups on the molecular benzene ring should be the main internal reasons for antioxidant synergistic behaviors. The photochemical strategy of concern is expected to provide benefits for on-site foods nutrition assays that should become a guide for health care diets.

Oxidized titanium carbide MXene-enabled photoelectrochemical sensor for quantifying synergistic interaction of ascorbic acid based antioxidants system

Antioxidants can protect organization from damage by scavenging of free radicals. When two kinds of antioxidants are consumed together, the total antioxidant capacity might be enhanced via synergistic interactions. Herein, we develop a simple, direct, and effective strategy to quantify the synergistic interaction between ascorbic acid (AA) and other different antioxidants by photoelectrochemical (PEC) technology. MXene Ti₃C₂-TiO₂ composites fabricated via hydrogen peroxide oxidation were applied as sensing material for the antioxidants interaction study. Under excitation of 470 nm wavelength, the photogenerated electrons transfer from the conduction band of TiO₂ nanoparticles to the Ti₃C₂ layers, and the holes in TiO₂ can oxidize antioxidants, leading to an enhanced photocurrent as the detection signal. This PEC sensor exhibits a good linear range to AA concentrations from 12.48 to 521.33 μM as well as obvious antioxidants capability synergism. In particular, the photocurrents of AA + gallic acid (GA) and AA + chlorogenic acid (CHA) mixtures at 476.19 μM increase 1.95 and 2.35 times respectively comparing with the sum of photocurrents of AA and GA or CHA. It is found that the synergistic effect is mainly depending on the fact that AA with the low redox potential (0.246 V vs NHE) can reduce other antioxidants radical to promote regeneration, improving the overall antioxidant performance. Moreover, it is proved that the greater redox potential of antioxidants, the more obvious the synergistic effect. In addition, the sensor was used to real sample assay, which provides available information towards food nutrition analysis, health products design and quality inspection.

Dietary Polyphenol Supplementation in Food Producing Animals: Effects on the Quality of Derived Products

Simple Summary

Polyphenols are secondary plant metabolites mainly known for their antioxidant properties. Their use as feed additives in the nutrition of farm animals is becoming increasingly popular as they are particularly exposed to oxidative stress which is reflected in a lipoperoxidation of the final product. For this reason, it is essential to preserve the quality and the safety of meat and milk products by attenuating oxidative deterioration. Moreover, polyphenols present the advantage of being more acceptable to the consumers than synthetic counterparts, as they are considered to be “non-toxic”. The present review presents an overview of several studies focused on the dietary supplementation of polyphenols to monogastric and ruminants, as well as their direct addition to meat and dairy products, with particular emphasis on their antioxidant effects on the final product.

Abstract

The growing interest in producing healthier animal products with a higher ratio of polyunsaturated to saturated fatty acids, is associated with an increase in lipoperoxidation. For this reason, it is essential to attenuate oxidative deterioration in the derived products. Natural antioxidants such as polyphenols represent a good candidate in this respect. The first part of the review highlights the occurrence, bioavailability, and the role of polyphenols in food-producing animals that, especially in intensive systems, are exposed to stressful situations in which oxidation plays a crucial role. The second part offers an overview of the effects of polyphenols either supplemented to the diet of monogastric and ruminants or added directly to meat and dairy products on the physicochemical and sensorial properties of the product. From this review emerges that polyphenols play an important, though not always clear, role in the quality of meat and meat products, milk and dairy products. It cannot be ruled out that different compounds or amounts of polyphenols may lead to different results. However, the inclusion of agro-industrial by-products rich in polyphenols, in animal feed, represents an innovative and alternative source of antioxidants as well as being useful in reducing environmental and economic impact.

Screening of highly effective mixed natural antioxidants to improve the oxidative stability of microalgal DHA-rich oil

Docosahexaenoic acid (DHA)-rich oil sourced from microalgae can easily become oxidized. The objective of this work was to screen the optimal natural antioxidant mixture for protecting DHA-rich oil. Different natural antioxidants, encompassing tea polyphenols, natural vitamin E, rosemary extract, licorice root antioxidant, ascorbyl palmitate and lecithin were tested individually and in combination in an accelerated oxidation process. Three antioxidants namely natural vitamin E, rosemary extract and ascorbyl palmitate with synergistic effects were chosen, and their concentrations were further optimized using response-surface methodology. The highest antioxidants activity of 16.1740 was obtained with a combination of 0.0224% vitamin E, 0.0259% rosemary extract and 0.0166% ascorbyl palmitate, which prolonged the time until oxidation induction to 20.21 days. The mixed natural antioxidants showed a similar antioxidant effect to 0.02% tert-butylhydroquinone and was better than 0.02% butylated hydroxyanisole. These data indicate that the mixed natural antioxidants optimized in this work can be directly applied in the protection of commercial microalgal DHA-rich oil.

Veiled Extra Virgin Olive Oils: Role of Emulsion, Water and Antioxidants

This review traces the current knowledge on the effects of various factors and phenomena that occur at interface, and the role of dispersed phase on the physicochemical, sensorial and nutritional characteristics of veiled extra virgin olive oil (VVOO). Since 1994 there have been numerous articles in the literature regarding the peculiar characteristic of unfiltered olive oil, so-called veiled or cloud virgin olive oil. It is a colloidal system (emulsion–sol), where the continuous lipidic phase dispreads mini droplets of milling water, fragments of cells and biotic fraction obtained from oil processing. During storage, the dispersed phase collapses and determines the quality of the virgin olive oil (VOO). The observed phenomena lead to worsening the quality of the product by causing defects such as oxidation of phenols, triacylglycerols hydrolysis and off-flavor formation. The addition of bioactive compounds, such as vitamins, on product based on VVOO, must take into account the eventual synergistic effect of individual substances. The role of the interphase is crucial to the synergic activity of bioactive molecules in improving oxidative stability, sensorial and health characteristics of VVOO.

Antioxidant Effect of Vitamins in Olive Oil Emulsion

In this study, water-in-extra virgin olive oil emulsions were enriched with vitamins. Water-in oil emulsions are heterogeneous systems able to solubilize both hydrophilic and hydrophobic compounds. Thus, hydrophilic vitamin C and lipophilic vitamin E were loaded separately or together in emulsion. A suitable emulsion composition was selected after considering different surfactant (mono and diglycerides of fatty acids, E471; sorbitan monooleate, Span 80; polyoxyethylene sorbitan monooleate, Tween 80) and water concentrations. The most appropriate emulsion, for the high stability, resulted the one containing concentrations of Span 80 1% w/w and water 1% w/w. The antioxidant effect of vitamins in emulsions was studied considering the variation of the peroxide values during storage. The oxidation reaction was slowed down in emulsions containing vitamin C, but it was quickened by the loading of vitamin E for its high concentration. In emulsions containing vitamin E, indeed, the peroxide values were higher than in emulsions prepared in the absence of vitamins or in oil. The antioxidant activity generated by the co-loading of vitamin C and E was very effective to the point that in presence of high amounts of vitamins the peroxide values did not change in about 40 days of storage, due to the vitamin E regeneration by vitamin C.

In Vitro Digestion of Grape Seed Oil Inhibits Phospholipid-Regulating Effects of Oxidized Lipids

The intake of dietary lipids is known to affect the composition of phospholipids in gastrointestinal cells, thereby influencing passive lipid absorption. However, dietary lipids rich in polyunsaturated fatty acids, such as vegetable oils, are prone to oxidation. Studies investigating the phospholipid-regulating effect of oxidized lipids are lacking. We aimed at identifying the effects of oxidized lipids from moderately (18.8 ± 0.39 meq O₂/kg oil) and highly (28.2 ± 0.39 meq O₂/kg oil) oxidized and in vitro digested cold-pressed grape seed oils on phospholipids in human gastric tumor cells (HGT-1). The oils were analyzed for their antioxidant constituents as well as their oxidized triacylglycerol profile by LC-MS/MS before and after a simulated digestion. The HGT-1 cells were treated with polar oil fractions containing epoxidized and hydroperoxidized triacylglycerols for up to six hours. Oxidized triacylglycerols from grape seed oil were shown to decrease during the in vitro digestion up to 40% in moderately and highly oxidized oil. The incubation of HGT-1 cells with oxidized lipids from non-digested oils induced the formation of cellular phospholipids consisting of unsaturated fatty acids, such as phosphocholines PC (18:1/22:6), PC (18:2/0:0), phosphoserine PS (42:8) and phosphoinositol PI (20:4/0:0), by about 40%–60%, whereas the incubation with the in vitro digested oils did not affect the phospholipid metabolism. Hence, the gastric conditions inhibited the phospholipid-regulating effect of oxidized triacylglycerols (oxTAGs), with potential implications in lipid absorption.

Synergy between plant phenols and carotenoids in stabilizing lipid-bilayer membranes of giant unilamellar vesicles against oxidative destruction

We have investigated the synergism between plant phenols and carotenoids in protecting the phosphatidylcholine (PC) membranes of giant unilamellar vesicles (GUVs) from oxidative destruction, for which chlorophyll-a (Chl-a) was used as a lipophilic photosensitizer. The effect was examined for seven different combinations of β-carotene (β-CAR) and plant phenols. The light-induced change in GUV morphology was monitored via conventional optical microscopy, and quantified by a dimensionless image-entropy parameter, ΔE. The ΔE-t time evolution profiles exhibiting successive lag phase, budding phase and ending phase could be accounted for by a Boltzmann model function. The length of the lag phase (LP in s) for the combination of syringic acid and β-CAR was more than seven fold longer than for β-CAR alone, and those for other different combinations followed the order: salicylic acid < vanillic acid < syringic acid > rutin > caffeic acid > quercetin > catechin, indicating that moderately reducing phenols appeared to be the most efficient membrane co-stabilizers. The same order held for the residual contents of β-CAR in membranes after light-induced oxidative degradation as determined by resonance Raman spectroscopy. The dependence of LP on the reducing power of phenols coincided with the Marcus theory plot for the rate of electron transfer from phenols to the radical cation β-CAR˙⁺ as a primary oxidative product, suggesting that the plant phenol regeneration of β-CAR plays an important role in stabilizing the GUV membranes, as further supported by the involvement of CAR˙⁺ and the distinct shortening of its lifetime as shown by transient absorption spectroscopy.

In-vitro bioaccessibility of spray dried refined kenaf (Hibiscus cannabinus) seed oil applied in coffee drink

This study aimed to investigate the effect of a coffee beverage matrix on the oil release percentage and bioaccessibility of bioactive compounds from microencapsulated refined kenaf seed oil (MRKSO) using an in vitro gastrointestinal digestion model. Refined kenaf seed oil was spray-dried with gum arabic, β-cyclodextrin, and sodium caseinate. Oil release percentage, total phenolic content, radical scavenging activity of DPPH and ABTS, tocopherol and tocotrienol contents, as well as phytosterol content, were measured in the oil released from digested MRKSO along with the coffee matrix and compared to the digested MRKSO without coffee matrix and undigested MRKSO. Refined kenaf seed oil showed a significantly higher oxidative stability index than crude, degummed, and neutralized oil samples. About 91.2 and 94.7% of the oils were released from the digested MRKSO without and with coffee matrix, respectively. Oil released from the digested MRKSO with coffee matrix showed an increase in the total phenolic content (200.5%), DPPH (172.7%), and ABTS (68.1%) values, tocopherol and tocotrienol contents (24.6%), as well as the phytosterol content (62.0%), compared to oil released from the digested MRKSO without coffee matrix. MRKSO was successfully incorporated in the coffee drink and can use as a partial replacement for coffee creamers or supplementation in coffee drinks.

Antioxidant mechanism of tea polyphenols and its impact on health benefits

Tea trees have a long history of cultivation and utilization. People in many countries have the habit of drinking tea and choosing green tea, oolong tea, or black tea according to different regions and personal tastes. Tea polyphenols are a general term for polyphenol compounds in tea, and has been shown to have good effects on antioxidant, anti-inflammatory, cancer prevention and regulation of lipid metabolism. Tea polyphenols have been widely used as antioxidants in disease treatment and animal husbandry, but their specific mechanism of action needs to be further clarified and revealed. This review focuses on the definition, classification, antioxidant activity and the regulation of signaling pathways of tea polyphenols. This paper also aims to examine the application of tea polyphenols in human and animal health, providing a scientific basis for this application in addition to proposing future directions for the development of this resource.

Plant Extracts and Reactive Oxygen Species as Two Counteracting Agents with Anti- and Pro-Obesity Properties

Obesity is a complex disease of great public health significance worldwide: It entails several complications including diabetes mellitus type 2, cardiovascular dysfunction and hypertension, and its prevalence is increasing around the world. The pathogenesis of obesity is closely related to reactive oxygen species. The role of reactive oxygen species as regulatory factors in mitochondrial activity in obese subjects, molecules taking part in inflammation processes linked to excessive size and number of adipocytes, and as agents governing the energy balance in hypothalamus neurons has been examined. Phytotherapy is the traditional form of treating health problems using plant-derived medications. Some plant extracts are known to act as anti-obesity agents and have been screened in in vitro models based on the inhibition of lipid accumulation in 3T3-L1 cells and activity of pancreatic lipase methods and in in vivo high-fat diet-induced obesity rat/mouse models and human models. Plant products may be a good natural alternative for weight management and a source of numerous biologically-active chemicals, including antioxidant polyphenols that can counteract the oxidative stress associated with obesity. This review presents polyphenols as natural complementary therapy, and a good nutritional strategy, for treating obesity without serious side effects.

Detection of synergistic effect of superoxide dismutase and jujubosides on scavenging superoxide anion radical by capillary electrophoresis

A new capillary electrophoresis method was developed to study the synergistic effect of superoxide dismutase and jujuboside A or B on scavenging superoxide anion radical in serum matrix respectively, in which superoxide anion radical was generated from pyrogallol autoxidation. The electrophoresis conditions, and the factors affecting the productive rate of purpurogallin, such as pyrogallol autoxidation product and the activity of superoxide dismutase, were optimized. Under optimal conditions, the content of superoxide dismutase in Gibco newborn calf serum was 7.06 mg/L, RSD was 2.01% and the average recovery was 98.4%. The values of IC₅₀ for jujuboside A and B in the serum matrix were 157.67 and 31.60 mg/L respectively, and they both had synergy on scavenging superoxide anion radical with superoxide dismutase, but there was no the dose-dependency on this synergy.

Scrutinizing antioxidant interactions between green tea and some medicinal plants commonly used as herbal teas

Meta-analysis reports suggested that green tea (GT) consumption is associated with mild to moderate effects on major global killers. To enhance the health promoting potential of GT, one of the strategies is to combine it with traditionally used medicinal plants (Ocimum gratissimum, Cymbopogon citratus, Cymbopogon flexuosus, and Hibiscus rosa-sinensis). The aim of this investigation was to evaluate and compare the possible synergistic antioxidant interaction of binary combinations of GT with medicinal plants. Overall, GT and O. gratissimum combination showed the highest antioxidant potential and strongest synergistic interaction at EC₅₀ . A strong correlation was found between antioxidant capacity (DPPH, ABTS, NO, and hemolysis) and total phenolic content (TPC) (except lipid peroxidation) for individual infusions, but very weak correlation was observed for GT combinations. Whereas, for both individual and binary aqueous infusions, moderate to strong correlation was observed between antioxidant parameters and FTIR-selected peak (3250-3290 cm^-1 ) omitting lipid peroxidation for single infusions. PRACTICAL APPLICATIONS: The combination of GT with certain medicinal plants used as herbal teas can demonstrate synergistic interactions that may boost the health promoting potential of GT. This study provides basis for future designing and formulation of beverages containing GT combinations based on their antioxidant interactions that can potentially enhance the efficacy of GT as a chemopreventive agent. It may also promote the consumption of GT combinations that may help in realizing untapped potential of underutilized plants.

Liposomal integration method for assessing antioxidative activity of water insoluble compounds towards biologically relevant free radicals: example of avarol

The liposomal integration method, in conjunction with electron paramagnetic resonance (EPR) spectroscopy, has been presented for the investigation of antioxidant activity of selected water-insoluble compound towards biologically relevant free radicals. This method was applied to avarol, a sesquiterpenoid hydroquinone isolated from the marine sponge Dysidea avara. The antioxidant activity of water-insoluble avarol towards ^•OH, O₂^•- and NO^• radicals was attained by its incorporation into the DPPC liposomes bilayer, and towards ascorbyl radicals in the organic solvent. Avarol's activity towards ^•OH, O₂^•-, NO^• and ascorbyl radicals was 86.2%, 50.9%, 23.6% and 61.8%, respectively, showing its significant radical scavenging potential.

Spectroscopic Studies on Dual Role of Natural Flavonoids in Detoxification of Lead Poisoning: Bench-to-Bedside Preclinical Trial

Ubiquitousness in the target organs and associated oxidative stress are the most common manifestations of heavy-metal poisoning in living bodies. While chelation of toxic heavy metals is important as therapeutic strategy, scavenging of increased reactive oxygen species, reactive nitrogen species and free radicals are equally important. Here, we have studied the lead (Pb) chelating efficacy of a model flavonoid morin using steady-state and picosecond-resolved optical spectroscopy. The efficacy of morin in presence of other flavonoid (naringin) and polyphenol (ellagic acid) leading to synergistic combination has also been confirmed from the spectroscopic studies. Our studies further reveal that antioxidant activity (2,2-diphenyl-1-picrylhydrazyl assay) of the Pb-morin complex is sustainable compared to that of Pb-free morin. The metal-morin chelate is also found to be significantly soluble compared to that of morin in aqueous media. Heavy-metal chelation and sustainable antioxidant activity of the soluble chelate complex are found to accelerate the Pb-detoxification in the chemical bench (in vitro). Considering the synergistic effect of flavonoids in Pb-detoxification and their omnipresence in medicinal plants, we have prepared a mixture (SKP17LIV01) of flavonoids and polyphenols of plant origin. The mixture has been characterized using high-resolution liquid chromatography assisted mass spectrometry. The mixture (SKP17LIV01) containing 34 flavonoids and 76 other polyphenols have been used to investigate the Pb detoxification in mouse model. The biochemical and histopathological studies on the mouse model confirm the dual action in preclinical studies.

Preliminary investigation on antioxidant interactions between bioactive components of Solanum anguivi and Capsicum annuum

Evaluation of antioxidative interaction between two fruits of contra-similar characteristics belonging to same botanical family Solanacea namely S. anguivi and Capsicum annuum was accomplished in this study. The relative reducing power (RRP) and radical scavenging activity (RSA) of the mixture (11:0, 10:1, 5:1, 2:1, 1:1, 1:2, 1:5,1:10, 0:11) with antioxidant interaction range of 0.6958-2.4244 and 0.724-1.648 was obtained for RRP and RSA respectively for acetone-hexane derived extract. Similarly antioxidant interaction range from 1.045-1.486 to 1.0969-1.3166 was obtained for RRP and RSA respectively for ethanolic extract samples.This study demonstrated enhanced activity of S. anguivi and C. annuum when used as a mixture in comparison to when used alone. These results suggested that application of S. anguivi and C. annuum as mixture decreased intensity of undesirable sensory properties of high intensity bitterness and hot pungency associated with S. anguivi and C. annuum respectively without the use of taste masking agents.

The synergistic potential of various teas, herbs and therapeutic drugs in health improvement: a review

Tea is one of the most widely consumed non-alcoholic beverages in the world next to water. It is classified as Camellia sinensis and non-Camellia sinensis (herbal teas). The common bioactive compounds found mainly in green teas are flavan-3-ols (catechins) (also called flavanols), proanthocyanidins (tannins) and flavonols. Black tea contains theaflavins and thearubigins and white tea contains l-theanine and gamma-aminobutyric acid (GABA), while herbal teas contain diverse polyphenols. Phytochemicals in tea exhibit antimicrobial, anti-diabetic and anti-cancer activities that are perceived to be helpful in managing chronic diseases linked to lifestyle. Many of these phytochemicals are reported to be biologically active when combined. Knowledge of the synergistic interactions of tea with other teas or herbs in terms of biological activities will be of benefit for therapeutic enhancement. There is evidence that various types of teas act synergistically in exhibiting health benefits to humans, improving consumer acceptance and economic value. Similar observations have been made when teas and herbs or medicinal drugs were combined. The aim of this review is to highlight potential beneficial synergies between combinations of different types of teas, tea and herbs, and tea and medicinal drugs. © 2017 Society of Chemical Industry.

Free radicals and polyphenols: The redox chemistry of neurodegenerative diseases

The oxidation of bioorganic materials by air and, particularly, the oxidative stress involved in the cell loss and other pathologies associated with neurodegenerative diseases (NDs) are of enormous social and economic importance. NDs generally involve free radical reactions, beginning with the formation of an initiating radical by some redox, thermal or photochemical process, causing nucleic acid, protein and lipid oxidations and the production of harmful oxidative products. Physically, persons afflicted by NDs suffer progressive loss of memory and thinking ability, mood swings, personality changes, and loss of independence. Therefore, the development of antioxidant strategies to retard or minimize the oxidative degradation of bioorganic materials has been, and still is, of paramount importance. While we are aware of the importance of investigating the biological and medical aspects of the diseases, elucidation of the associated chemistry is crucial to understanding their progression, heading to intelligent chemical intervention to find more efficient therapies to prevent or delay the onset of the diseases. Accordingly, this review aims to provide the reader with a chemical base to understand the behavior and properties of the reactive oxygen species involved and of typical radical scavengers such as polyphenolic antioxidants. Some discussion on the structures of the various species, their formation, chemical reactivities and lifetimes is included. The ultimate goal is to understand how, when and where they form, how far they travel prior to react, which molecules are their targets, and how we can, eventually, control their activity to minimize their impact by means of chemical methods. Recent strategies explore chemical modifications of the hydrophobicity of potent, natural antioxidants to improve their efficiency by fine-tuning their concentrations at the reaction site.

Astaxanthin in cardiovascular health and disease: mechanisms of action, therapeutic merits, and knowledge gaps

Cardiovascular disease is the main contributor to morbidity and mortality worldwide.

Antioxidant edible films based on chitosan and starch containing polyphenols from thyme extracts

The aim of this study was to analyse the antioxidant activity of different polymeric matrices based on chitosan and starch, incorporating a thyme extract (TE) rich in polyphenols. TE provided the films with remarkable antioxidant activity. When mixed with chitosan, the polyphenols interacted with the polymer chains, acting as crosslinkers and enhancing the tensile behaviour of films. The opposite effect was observed when incorporated into the starch matrix. All the films became darker, more reddish and less transparent when TE was incorporated. These colour changes were more marked in starch matrices, which suggests that TE compounds were poorly encapsulated. The use of chitosan-based matrices carrying TE polyphenols is recommended as a means of obtaining antioxidant films, on the basis of their tensile response and greater antioxidant activity, which could be associated with the development of polyphenol-chitosan interactions, contributing to a better protection of the functionality of polyphenols during film formation and conditioning.

Evaluation of Antioxidant Interactions of Combined Model Systems of Phenolics in the Presence of Sugars

The aim of this study was to determine the antioxidant activity of model systems of phenolics (individual and combinations) without and with the addition of sugars (sucrose or trehalose). Also, the synergistic or antagonistic effects of the phenolics in all model systems were evaluated. The results for the antioxidant activity were obtained by three assays, ABTS+•, DPPH• and FRAP. ABTS+• and DPPH• assay showed that quercetin and gallic acid had the same antioxidant activity, higher than catechin. When the FRAP assay was applied, the order of increasing of antioxidant activity was quercetin < gallic acid < catechin. The highest synergistic effect was achieved in the model system of catechin, quercetin and gallic acid. Addition of sugars, sucrose and trehalose, influenced both antioxidant activity and synergistic effect of phenolics in the model systems. The highest synergistic effect in the model systems with sucrose addition was observed with catechin, quercetin and gallic acid, while in samples with trehalose, the highest synergistic effect was in combination with catechin and gallic acid. Interactions of phenolics and phenolics/sugars caused changes in antioxidant activity as well as synergistic effects.

Vitamin E slows down the progression of osteoarthritis

Osteoarthritis is a chronic degenerative joint disorder with the characteristics of articular cartilage destruction, subchondral bone alterations and synovitis. Clinical signs and symptoms of osteoarthritis include pain, stiffness, restricted motion and crepitus. It is the major cause of joint dysfunction in developed nations and has enormous social and economic consequences. Current treatments focus on symptomatic relief, however, they lack efficacy in controlling the progression of this disease, which is a leading cause of disability. Vitamin E is safe to use and may delay the progression of osteoarthritis by acting on several aspects of the disease. In this review, how vitamin E may promote the maintenance of skeletal muscle and the regulation of nucleic acid metabolism to delay osteoarthritis progression is explored. In addition, how vitamin E may maintain the function of sex organs and the stability of mast cells, thus conferring a greater resistance to the underlying disease process is also discussed. Finally, the protective effect of vitamin E on the subchondral vascular system, which decreases the reactive remodeling in osteoarthritis, is reviewed.

α-Tocopherol/Gallic Acid Cooperation in the Protection of Galactolipids Against Ozone-Induced Oxidation

The protective ability of α-tocopherol (TOH) and gallic acid (GA) acting simultaneously at the moment of oxidizer application was evaluated by determination of galactolipid layers’ oxidation degree. Addition of GA resulted in a significant decrease of ozone-derived radicals shifting the threshold of lipid sensitivity by an amount approximately corresponding to the GA intake in bulk reaction with ozone. TOH presence in lipid layers results in a change of the role of GA which additionally may be involved in the reduction of tocopheroxyl radical formed during oxidation. This leads to a decrease in effectiveness of GA in diminishing the amount of ozone radicals. Such an effect was not observed for mixed layers containing galactolipid and pre-oxidized tocopherol where the ozone threshold level was associated with a stoichiometry of GA + O₃ reaction. It was concluded that probably subsequent transformations of tocopheroxyl radical to less reactive forms prevent its reaction with GA the entire quantity of which is used for radicals scavenging. This result shows the role of time parameter in systems where substrates are engaged in various reactions taking place simultaneously. The inactivation of 1,1-diphenyl-2-picrylhydrazyl radical by studied antioxidants in homogeneous system confirmed observations made on the basis of lipid layer properties indicating their antagonistic action (at least at studied conditions). Formation of layers in post-oxidation situation did not depend whether tocopherol was oxidized during oxidation of lipid/tocopherol mixture or was introduced as pre-oxidized. This may be interpreted as indication that products of tocopherol oxidation may stabilize lipid layers.

Development of Active Films From Pectin and Fruit Extracts: Light Protection, Antioxidant Capacity, and Compounds Stability

Pectin films containing fruit extracts were developed and tested in relation to ultraviolet light transmission, phytochemical contents, and antioxidant capacity during 90 d shelf life storage. Aqueous and alcoholic extracts from 5 different fruits (acerola, cashew apple, papaya, pequi, and strawberry) were obtained. Because the alcoholic extracts from acerola, cashew apple, and strawberry presented the highest phytochemical content and antioxidant capacity, they were incorporated into pectin films individually or as a mixture. Incorporation of these extracts into pectin films provided antioxidant capacity while retaining the physical properties. The pectin films containing fruit extract acted as adequate light barrier and prevented photooxidation. Among the prepared films, the pectin film containing acerola extract afforded the highest antioxidant capacity, with a half-life of 99 d. Overall, the results revealed that incorporation of fruit extracts into pectin films potentially produces antioxidant films and coatings for different food applications.

PRACTICAL APPLICATION

The production of pectin films incorporated with fruit extract is based on combination of the antioxidant activity, natural color, and optical barrier properties from fruit phytochemical components to the active film. This film could be potentially used as active packing on food products in order to protect their nutrients against free radicals action and photooxidation and, hence, preserve the quality, integrity, and safety of food during the storage period.

Chitosan crosslinked microparticles with encapsulated polyphenols: Water sorption and release properties

Chitosan–glutaraldehyde microparticles were produced by emulsion crosslinking method to be used as drug delivery system for polyphenols from Thymus serpyllum L. aqueous extract. The effect of preparation conditions, chitosan concentration (1.5–3% w/v), and glutaraldehyde/chitosan (GA/Ch) mass ratio (0.15–1.20) on water and polyphenols transport properties was investigated. Swelling ratio of dry particles (68–230 µm) in water ranged from 280% to 530%, depending on the formulation. The decrease in swelling was observed with increased GA/Ch mass ratio (i.e. crosslinking degree) at the same chitosan concentration, or with increased chitosan concentration at the same GA/Ch mass ratio. The increase in GA/Ch mass ratio was also manifested by increased particle compactness i.e. decreased size and reduced surface roughness. The sorption capacity for polyphenols seems to be a complex interplay of swelling behaviour and interactions chitosan–glutaraldehyde–polyphenols identified by Fourier transmission infrared analysis. An increase in crystallinity of chitosan was observed upon crosslinking with glutaraldehyde and encapsulation of polyphenols, as observed by X-ray diffraction analysis. The results obtained from release kinetics of selected polyphenolic compounds (caffeic acid, rosmarinic acid, total flavonoids, and total phenol content) showed that polyphenols were released at a lower amount (2–4 times) in water, but more rapidly (45–120 min) in comparison with the release in gastric followed by intestinal simulated fluid (SGF-SIF) (120–240 min). The experimental results of the time-dependent swelling in water and polyphenols release in both, water and SGF-SIF, were analyzed with several mathematical models. The results depicted Fickian diffusion as the water transport mechanism. In the case of polyphenols, only empirical Weibull model could be suggested for describing release kinetics.