Cellular Antioxidant Assay Research Articles

Overview and Trends in Electrochemical Sensors, Biosensors and Cellular Antioxidant Assays for Oxidant and Antioxidant Determination in Food

Screening and quantifying antioxidants from food samples, their antioxidant activity, as well as the assessment of food oxidation is critical, not only for ensuring food quality and safety, but also to understand and relate these parameters to the shelf life, sensory attributes, and health aspects of food products. For this purpose, several methods have been developed and used for decades, which regardless of their effectiveness, present a certain number of drawbacks mainly related to extensive sample preparation and technical complexity, time requirement, and use of hazardous chemicals. Electrochemical sensors and biosensors are gaining popularity in food analysis due to their high sensitivity, specificity, rapid response times, and potential for miniaturisation and portability. Furthermore, other modern methods using whole living cells such as the cellular antioxidant activity assay, the antioxidant power 1 assay, and the catalase-like assays, may interpret more realistic antioxidant results rather than just reporting the ability of scavenging free radicals in isolated systems with extrapolation to the reality. This paper provides an overview on the electrochemical sensors, biosensors, and cellular antioxidant assays, and reviews the latest advancements and emerging trends in these techniques for determining oxidants and antioxidants in complex food matrices. The performances of different strategies are described for each of these approaches to provide insights into which extent these methods can be exploited in the field and inspire new research to fill the identifiable current gaps.

Structure, antioxidant activity, and neuroprotective effect of black soybean (Glycine max (L.) merr.) protein hydrolysates

The potential biological properties of protein hydrolysates have generated considerable research interest. This study was to hydrolyze black soybean protein (BSP) using five different commercial enzymes, and elucidate the influence of these enzymes on the structure and biological activities of the resulting hydrolysates. Enzymatic treatment changed secondary and tertiary structures of BSP, decreased particle size, α-helix and β-sheet. Alcalase hydrolysate had the highest hydrolytic degree (29.84 %), absolute zeta potential (38.43 mV), the smallest particle (149.87 nm) and molecular weight (<3 kDa). In silico revealed alcalase hydrolysate had the strongest antioxidant potential. This finding was further validated through the lowest IC50 (mg/mL) in DPPH (2.67), ABTS (0.82), Fe2+ chelating (1.33) and·OH (1.12). Moreover, cellular antioxidant assays showed alcalase hydrolysate had the strongest cytoprotective effects on H2O2-induced PC12 cells. These results suggest BSPEHs, especially those prepared by alcalase, have potential as bioactive ingredients for nutrition, healthcare and food industry.

Comparative profiling of secondary metabolites and antioxidant properties of twelve Morus varieties: Insights into the diversity of M. alba and M. nigra grown in Sicily

This work analyzed potential phytochemical differences in bioactive compounds, antioxidant activity and metabolic profiles of 12 different varieties of Morus alba and Morus nigra fruits grown in Sicily by Liquid chromatography coupled to High Resolution Mass Spectrometry. Through UV/Vis assays, variations in in bioactive compounds were observed, recording higher contents of polyphenols and anthocyanins in M. nigra species. Spectrophotometric assays also revealed the absence of ellagitannins and proanthocyanidins in the same samples, while the amount of anthocyanins varied not only among species but also among cultivars. From a functional point of view, both scavenging and radical-reducing abilities were evaluated by biochemical assays, while Cellular Antioxidant assay was used to monitor antioxidant properties on a human cell-based biological system. These assays confirmed that M. nigra varieties possessed higher antioxidant activity in terms of radical scavenging and reducing antioxidant power. On the other hand, the cellular model system provided insights into the potential health implications of Morus spp. with values comparable to other common berries. Finally, metabolomic analysis illuminated the chemical diversity within Morus spp. by highlighting distinct metabolic fingerprints and allowing discrimination between species and varieties. Anthocyanins emerged as key metabolites for this discrimination, with additional compounds contributing to genotype-specific profiles. Overall, these results underscore the importance of genetic diversity in assessing the health properties of Morus spp. with implications for improving their nutritional and medicinal value in Mediterranean areas, particularly Sicily.

Optimizing ultrasound-assisted extraction of bioactive compounds from Canthium horridum blume leaves utilizing polyols: A study on skin-related activities

The focus on reducing organic solvent usage, owing to their negative environmental and health impacts, is driving a search for innovative green alternative solvents in academia and industry. Canthium horridum Blume (CH) exhibits many therapeutic activities, including antioxidant and anti-inflammatory efficacy. The objective of this study is to evaluate the optimal solvent concentration using a simplex-lattice design with an aqueous-polyols mixture and to optimize the parameters for extracting bioactive compounds and antioxidant activities from ultrasound-assisted extraction (UAE) of CH leaves through central composite design (CCD) in response surface methodology (RSM). This study examines the total phenolic content (TPC), antioxidant activities, comparison of different extraction conditions, identification of bioactive compounds, cell cytotoxicity, cellular antioxidant activity, and melanin content reduction efficacy of the extracts. According to the findings from the simplex-lattice model, the ideal solvent composition consisted of 32.57%w/w butylene glycol, 32.92%w/w glycerine, and 34.51%w/w water. Furthermore, based on the response model, optimal extraction conditions were identified as a 15-min extraction time and a solvent-to-sample ratio of 32.94:1. In comparison to alternative extraction methods, ultrasonic-assisted extraction using the aqueous-glycerine-butylene glycol (GB-UAE) extract resulted in notably elevated TPC and antioxidant responses (p < 0.05). Major antioxidant bioactive compounds included 4-(Butoxymethyl) phenol, 3-O-Caffeoyl-4-O-methylquinic acid, Quercetin 3-(2G-glucosylrutinoside), 2,4-Dihydroxybenzoic acid and other bioactive compounds. The GB-UAE extract revealed greater cell viability than UAE using ethanol (EtOH-UAE) extract in both cytotoxicity and cellular antioxidant assays at the same concentration. Additionally, it exhibited comparable melanin content reduction efficacy at a higher concentration compared to that of EtOH-UAE extract. The researcher anticipates that the current study will advance the utilization of an aqueous-polyols system for extracting bioactive compounds extending beyond CH leaves. Although the potential applications of CH leaves in cosmetics and pharmaceutical formulations have been identified, further comprehensive mechanistic and clinical studies are required to fully understand their effects.

Supercritical antisolvent precipitation as a green technology to fractionate an Origanum majorana extract: Relationship between fractions cellular antioxidant activity and phytochemical composition.

The aim of this work was to determine the optimal conditions to fractionate a marjoram extract using supercritical antisolvent precipitation (SAS) technology in order to improve its antioxidant activity. This activity was evaluated using a cellular antioxidant assay (CAA) and compared to a chemical method (ABTS). After extract fractionation, most of the phenolics were recovered in the precipitate, except for the less polar ones that were found in the separators, along with essential oil components, non-volatile terpenes and fatty acids. Precipitate fractions obtained at 40 °C and 20–25 MPa showed the best TEAC values (1.7 mmol Trolox/g extract). Nevertheless, no precipitate fraction exerted better CAA than the unfractionated extract. This activity was related to the presence of arbutin and rosmarinic acid in their composition. In contrast, separators showed a low TEAC value (0.3 mmol Trolox/g), but a higher cellular antioxidant activity, especially fractions obtained at 15–20 MPa and 40–50 °C. This enhanced antioxidant activity was mainly attributed to the presence of ursolic acid, sterubin, menthol, sabinene hydrate and terpineol, compounds with a less polar character that therefore could cross more easily the cell membrane and exert their antioxidant activity inside the cells. Thus, separator fractions obtained at 20 MPa and 40 °C increased a 30% the CAA value respect to UAE extract and could be used for designing nutraceuticals or functional foods with cellular antioxidant activity. Precipitate fractions, at these extraction conditions, also showed an increase in TEAC value (40%) and could be employed as natural antioxidants in food formulations.

Surface modification by chitosan for improving stability and antioxidative activity of astaxanthin-loaded liposomes

Astaxanthin (AST) is a compound renowned for its extraordinary antioxidant and anti-inflammatory properties. However, its application is limited due to low solubility, instability and bioavailability. To overcome these drawbacks, we encapsulated AST in liposomes (AST-loaded liposomes, AST-LIP) using chitosan (CS) as coating materials by thin film dispersion and high-pressure homogenization. We examined the physicochemical characteristics (particle size, polydispersity index, zeta potential, encapsulation efficiency, fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analyzer (TGA)) of AST-LIP coated with various concentrations of CS, and confirmed the optimal concentration for the formulation of CS-coated AST-LIP was 1.5 mg/mL. Additionally, the storage stability and thermal stability analysis revealed that CS-AST-LIP exhibited significantly higher AST retention rates than AST-LIP under varying environmental conditions. Furthermore, CS-AST-LIP showed significantly higher DPPH·, OH· radical scavenging effects, and iron-reducing power than AST-LIP after storage for 4 weeks at 4 °C. For the cellular antioxidant assays, the CS-AST-LIP at the CS concentration of 1.5 mg/mL exhibited a satisfactory protective effect against oxidative damage induced by H2O2 in Raw264.7 cells. In conclusion, these findings highlight the potential of chitosan as a promising coating material for improving the storage stability, thermal stability and antioxidant activity of AST-LIP.

Antioxidant interaction between α-tocopherol and γ-oryzanol in HepG2 cells.

Minor constituents exhibit certain antioxidant interactions in vitro, and the effects in different media are different. However, it is not clear whether there are antioxidant interactions in cells after digestion and absorption. We utilized the cellular antioxidant evaluation model in HepG2 cells to study the antioxidant interaction between α-tocopherol and γ-oryzanol, and the interaction mechanism of a binary mixture was also illustrated. A cellular antioxidant assay (CAA) model and a combined index (CI) method were firstly used to explore the antioxidant activity and interaction of the binary mixture in HepG2 cells. The CAA value was positively correlated with the single addition concentration, while the results displayed a biphasic tendency with increasing concentrations of the binary mixture. The combination of TO11 (1 μg mL-1 α-tocopherol and 10 μg mL-1 γ-oryzanol) showed the greatest antioxidant activity and synergistic effect, and the maximum CAA value reached up to 94.84 ± 4.2. Then the mechanism of the synergistic antioxidant effect of the binary mixture was explained from three aspects including cellular uptake, intracellular reactive oxygen species (ROS) level and endogenous enzyme activity. The results demonstrated that the antioxidant interaction of the binary mixture in cells was related to cellular uptake of minor constituents, and the combination of TO11 exerted a synergistic effect by scavenging ROS and up-regulating glutathione peroxidase (GSH-Px) activity, resulting in the strongest cellular antioxidant activity. This study throws light on the nature of antioxidant interaction between minor constituents, which may contribute to the development of related functional foods and rational dietary collocation.

Volatile Compounds and Biological Activity of the Essential Oil of Aloysia citrodora Paláu: Comparison of Hydrodistillation and Microwave-Assisted Hydrodistillation.

Aromatic plants are a remarkable source of natural products. Aloysia citrodora Paláu (Verbenaceae), commonly known as lemon verbena, is a relevant source of essential oils with potential applications due to its lemony scent and bioactive properties. Studies carried out on this species have focused on the volatile composition of the essential oil obtained by Clevenger hydrodistillation (CHD), with little information available on alternative extraction methodologies or the biological properties of the oil. Therefore, this work aimed to compare the volatile composition, antioxidant activity, cytotoxicity, anti-inflammatory and antibacterial activities of the essential oil extracted by conventional hydrodistillation by Clevenger (CHD) and Microwave-Assisted Hydrodistillation (MAHD). Significant differences (p < 0.05) were observed for some compounds, including the two major ones, geranial (18.7-21.1%) and neral (15.3-16.2%). Better antioxidant activity was exhibited by the MAHD essential oil in DPPH radical scavenging and reducing power assays, while no differences were observed in the cellular antioxidant assay. The MADH essential oil also presented higher inhibition against four tumoral cell lines and exhibited lower cytotoxicity in non-tumoral cells as compared with Clevenger-extracted essential oil. In contrast, the latter showed higher anti-inflammatory activity. Both essential oils were able to inhibit the growth of eleven out of the fifteen bacterial strains tested.

Wine Lees as Source of Antioxidant Molecules: Green Extraction Procedure and Biological Activity

An ultrasound-assisted extraction method, employing ethanol and water as solvents at low temperature (30 °C) and reduced time (15 min), was proposed to extract bioactive molecules from different cultivars (Magliocco Canino, Magliocco Rosato, Gaglioppo, and Nocera Rosso) of wine lees. All the extract yields were evaluated and their contents of phenolic acids, flavonoids, and total polyphenols were determined by means of colorimetric assays and high-performance liquid chromatography coupled with diode-array detection (HPLC-DAD) and Fourier transform infrared (FTIR) techniques. Radical scavenging assays were performed and the Magliocco Canino extracted with a hydroalcoholic mixture returned the best results both against ABTS (0.451 mg mL-1) and DPPH (0.395 mg mL-1) radicals. The chemometric algorithms principal component analysis (PCA) and partial least square regression (PLS) were used to process the data obtained from all qualitative-quantitative sample determinations with the aim of highlighting data patterns and finding possible correlations between composition and antioxidant features of the different wine lees cultivars and the extraction procedures. Wine lees from Magliocco Canino and Magliocco Rosato were found to be the best vegetable matrices in terms of metabolite content and antioxidant properties. The components extracted with alcoholic or hydroalcoholic solvents, specifically (-)-epigallocatechin gallate, chlorogenic acid, and trans-caftaric acid, were found to be correlated with the antioxidant capacity of the extracts. Multivariate data processing was able to identify the compounds related to the antioxidant features. Two PLS models were optimized by using their concentration levels to predict the IC50 values of the extracts in terms of DPPH and ABTS with high values of correlation coefficient R2, 0.932 and 0.824, respectively, and a prediction error lower than 0.07. Finally, cellular (SH-SY5Y cells) antioxidant assays were performed on the best extract (the hydroalcoholic extract of Magliocco Canino cv) to confirm its biological performance against radical species. All these recorded data strongly outline the aptness of valorizing wine lees as a valuable source of antioxidants.

A study of the antioxidant properties of Keggin-type polyoxometalates.

In this paper, we used extracellular reactive oxygen radical scavenging assay and cellular antioxidant assay to investigate the antioxidant ability of Keggin-type polyoxometalates on the inside and outside of cells influenced by three different factors: heteroatom substitution, transition metal substitution and the number of vanadium substitutions. The results showed that the IC50 values of heteroatomic (P, Si, Ga) polyoxometalates on superoxide anion radical scavenging were 1.32 ± 0.00047 mg mL-1, 17.49 ± 2.47500 mg mL-1, and 66.99 ± 20.0227 mg mL-1, respectively. In comparison, PMo12 had the best ability to scavenge free radicals, and the SOD activity of PMo12 at 12.5 μmol L-1 increased by 50% compared with that of the unspiked drug, which played an antioxidant role; the scavenging effect of superoxide anion radicals of PMo11Mn in transition metals (Fe, Mn, Cu) instead of polyoxometalate (IC50 value 1.18 ± 0.0008 mg mL-1) was lower than that of unsubstituted PMo12 (IC50 value 1.32 ± 0.00047 mg mL-1), where PMo11Mn was nearly 1.5 times higher than PMo11Cu administration to reduce the number of cells by half; the PMo11V, PMo10V2, PMo9V3, PMo8V4, PMo7V5 hydroxyl radical scavenging rates (IC50 values) were 0.19 ± 0.0011 mg mL-1, 0.22 ± 0.0027 mg mL-1, 0.03 ± 0.0014 mg mL-1, 0.04 ± 0.0008 mg mL-1, and 0.11 ± 0.0005 mg mL-1, respectively, and in comparison, scavenging of PMo9V3 radicals was more effective and they acted as an antioxidant. Therefore, they can be used as good antioxidants in biological and pharmaceutical applications and play an important role in the treatment of tumours, cancer, Alzheimer's disease and other diseases.

Effects of polyphenolic-rich extracts from Citrus hystrix on proliferation and oxidative stress in breast and colorectal cancer

Abstract Objectives The anti-proliferative effects of Citrus hystrix have been reported. However, information on breast and colorectal cancer is limited especially the mechanistic aspects. In this study, the antioxidant activities of hexane, ethyl acetate, methanol and water extracts of C. hystrix leaves and their growth inhibitory effects on colorectal (HCT 116) and breast cancer (MCF 7, MDA-MB 231 and HCC 1937) cells were analysed. Methods Antioxidant and oxidative stress status were measured using non-cellular and cellular assays. Caspase and gene expression were utilized to determine anti-proliferative effects. Polyphenolic content was analysed using LC-IT-TOF/MS. Results The water extract showed the highest polyphenolic content and antioxidant activities (FRAP, DPPH, ABTS, superoxide anion radical scavenging, ferrous ion chelation, cellular antioxidant assay). The ethyl acetate extracts of C. hystrix (CH-EA) demonstrated the highest anti-proliferative activity against all cancer cell lines (IC50&lt;100 μg/mL). Increase in ROS was observed in CH-EA-treated HCT 116, MDA-MB 231 and HCC 1937 cells (p&lt;0.05). Increase in caspase activities and upregulation of Bax, Bcl-2, Cdk-1, TP53 and TNF-α expression in HCT 116 cells indicated activation of apoptosis by CH-EA. LC-IT-TOF/MS analysis indicated presence of quercetin and rutin in CH-EA. Conclusions CH-EA showed anti-proliferative effects, possibly through modulation of oxidative stress and apoptosis.

Antioxidant, cytotoxic, and antibacterial activities of Clitoria ternatea flower extracts and anthocyanin-rich fraction

Clitoria ternatea flower is a traditional medicinal herb that has been used as a natural food colourant. As there are limited studies on investigating the bioactivities of the anthocyanin-rich fraction of Clitoria ternatea flower, this study aimed to determine an efficient column chromatography method to obtain the anthocyanin-rich fraction from this flower and characterise its composition, antioxidant, antibacterial, and cytotoxic activities. Amberlite XAD-16 column chromatography was more efficient in enriching the total anthocyanin content (TAC) of the fraction with the highest TAC to total phenolic content (TPC) ratio of 1:6 than that using C18-OPN. A total of 11 ternatin anthocyanins were characterised in the anthocyanin-rich fraction by LC–MS analysis. The antioxidant activity of the anthocyanin-rich fraction was more potent in the chemical-based assay with an IC50 value of 0.86 ± 0.07 mg/mL using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay than cellular antioxidant assay using RAW 264.7 macrophages. In vitro cytotoxicity assay using human embryonic kidney HEK-293 cell line showed the anthocyanin-rich fraction to be more toxic than the crude extracts. The anthocyanin-rich fraction had more potent antibacterial activity than the crude extracts against Bacillus cereus, Bacillus subtilis, and Escherichia coli. The anthocyanin-rich fraction of C. ternatea has the potential to be used and developed as a functional food ingredient or nutraceutical agent.

Optimization of ultrasound-assisted extraction of bioactive compounds from coffee pulp using propylene glycol as a solvent and their antioxidant activities

In the cosmetic and pharmaceutical industries, it has been increasingly popular to use alternative solvents in the extraction of bioactive compounds from plants. Coffee pulp, a by-product of coffee production, contains different phenolic compounds with antioxidant properties. The effects of polyols, amplitude, extraction time, solvent concentration, and liquid–solid ratio on total phenolic content (TPC) using ultrasound-assisted extraction (UAE) were examined by single-factor studies. Three main factors that impact TPC were selected to optimize the extraction conditions for total phenolic content (TPC), total flavonoid content (TFC), total tannin content (TTC), and their antioxidant activities using the Box-Behnken design. Different extraction methods were compared, the bioactive compounds were identified and quantified by liquid chromatography triple quadrupole mass spectrometer (LC-QQQ), and the cytotoxicity and cellular antioxidant activities of the extract were studied. According to the response model, the optimal conditions for the extraction of antioxidants from coffee pulp were as follows: extraction time of 7.65 min, liquid–solid ratio of 22.22 mL/g, and solvent concentration of 46.71 %. Under optimized conditions, the values of TPC, TFC, TTC, 1,1-diphenyl-2-picryl-hydrazil (DPPH) radical scavenging assay, 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) radical scavenging assay, and Ferric reducing antioxidant power assay (FRAP) were 9.29 ± 0.02 mg GAE/g sample, 58.82 ± 1.38 mg QE/g sample, 8.69 ± 0.25 mg TAE/g sample, 7.56 ± 0.27 mg TEAC/g sample, 13.59 ± 0.25 mg TEAC/g sample, and 10.90 ± 0.24 mg FeSO4/g sample, respectively. Compared with other extraction conditions, UAE with propylene glycol extract (PG-UAE) was significantlyhigher in TPC, TFC, TTC, DPPH, ABTS, and FRAP response values than UAE with ethanol (EtOH-UAE), maceration with propylene glycol (PG-maceration), and maceration with ethanol (EtOH -maceration) (p < 0.05). Major bioactive compounds detected by LC-QQQ included chlorogenic acid, caffeine, and trigonelline. At higher concentrations starting from 5 mg/ml, PG-UAE extract showed higher cell viability than EtOH-UAE in both cytotoxicity and cellular antioxidant assays. The researcher expects that this new extraction technique developed in this work could produce a higher yield of bioactive compounds with higher biological activity. Therefore, they can be used as active ingredients in cosmetics (anti-aging products) and pharmaceutical applications (food supplements, treatment for oxidative stress-related diseases) with minimal use of chemicals and energy.

Evaluation of biosafety and skin-care efficacy for “Four white” medicinal materials used in cosmetics

ObjectiveTo verify the antioxidant, whitening and anti-inflammatory effects of “Four white” extracts in cosmetic applications. MethodsThe extracts of the Chinese herbal medicines “Four white” (Silkworm Larva, Japanese Ampelopsis root, Largehead Atractylodes rhizome. White peony root) were prepared by an alcoholic extraction method. The safety and irritation of the extracts were assessed by the erythrocyte hemolysis test and MTT. The antioxidant ability of the extracts was determined by measuring their capabilities to scavenge hydroxyl and DPPH radicals, reduce iron ions and cellular antioxidant assays. The whitening capability was determined by the ability of tyrosinase inhibition. Its anti-inflammatory capacity was determined by measuring the inhibiting rates against hyaluronidase and lipopolysaccharide (LPS)-induced NO production in RAW264.7 cells. ResultsThe results of the irritation test showed that the “Four white” extract has low irritation and high biosafety. It can scavenge different free radicals and has protective effect against oxidative damage. The tyrosinase inhibition test showed that the extracts had whitening ability. In terms of anti-inflammatory activity, it can inhibit hyaluronidase activity to a certain extent and reduce the production of NO by LPS-stimulated cells. Conclusion“Four white” extract has high biosafety and skin-care efficiency such as antioxidant, whitening and anti-inflammatory properties.

Validation of a High-Performance Liquid Chromatography with Photodiode Array Detection Method for the Separation and Quantification of Antioxidant and Skin Anti-Aging Flavonoids from Nelumbo nucifera Gaertn. Stamen Extract.

Nelumbo nucifera Gaertn., or the so-called sacred lotus, is a useful aquatic plant in the Nelumbonaceae family that has long been used to prepare teas, traditional medicines as well as foods. Many studies reported on the phytochemicals and biological activities of its leaves and seeds. However, to date, only few studies were conducted on its stamen, which is the most important ingredient for herbal medicines, teas and other phytopharmaceutical products. Thus, this present study focuses on the following: (1) the application of high-performance liquid chromatography with photodiode array detection for a validated separation and quantification of flavonoids from stamen; (2) the Nelumbo nucifera stamen’s in vitro and in cellulo antioxidant activities; as well as (3) its potential regarding the inhibition of skin aging enzymes for cosmetic applications. The optimal separation of the main flavonoids from the stamen ethanolic extract was effectively achieved using a core-shell column. The results indicated that stamen ethanolic extract has higher concentration of in vitro and in cellulo antioxidant flavonoids than other floral components. Stamen ethanolic extract showed the highest protective effect against reactive oxygen/nitrogen species formation, as confirmed by cellular antioxidant assay using a yeast model. The evaluation of potential skin anti-aging action showed that the stamen extract has higher potential to inhibit tyrosinase and collagenase compared with its whole flower. These current findings are the first report to suggest the possibility to employ N. nucifera stamen ethanolic extract as a tyrosinase and collagenase inhibitor in cosmetic applications, as well as the utility of the current separation method.

Cellular antioxidant properties of nontoxic exopolysaccharide extracted from Lactobacillales (Weissella cibaria) isolated from Korean kimchi

The present work isolated and identified five lactic acid bacteria (LAB) from Korean kimchi and then evaluated their exopolysaccharide (EPS) production efficiency. SY003 (Weissella cibaria) produced a high level of EPS when compared to the other isolates. Therefore, EPS from SY003 was selected for purification and characterization using column chromatography, HPLC, FTIR, and NMR. The HPLC analysis indicated that EPS was composed of glucose (38.95%) and galactose (61.04%). FTIR and NMR results confirmed that monosaccharides of EPS were linked through α-D-Glc-(1 → and →6)-β-D-Gal-(1→ linkage. SEM results displayed the nonporous and smooth surface of EPS. In the antioxidant assay, EPS (1 mg/mL) scavenged 34% of DPPH and 90% of ABTS+. Additionally, toxicological experiments (CAM assay, hemolysis assay, and cytotoxicity) established that EPS was nontoxic and biocompatible for biomedical applications. EPS (1 mg/mL) protected HEK293 cells from H2O2 induced oxidative stress shown by cellular antioxidant assay. The present work concluded that EPS produced from W. cibaria (SY003) isolated from Korean kimchi was biocompatible and merited consideration for the development of antioxidant agents.

Effect of bovine serum albumin on the stability and antioxidant activity of blueberry anthocyanins during processing and in vitro simulated digestion

The application of blueberry anthocyanins (ANs) was limited due to their low in-process stability and bioavailability. In our study, the stability and antioxidant capacity of ANs before and after adding bovine serum albumin (BSA) were examined by simulating various processing, storage (light, sucrose, and vitamin C (Vc)), and in vitro simulated digestion parameters. For this purpose, pH-differential method, high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), peroxyl scavenging capacity assay, and cellular antioxidant assay were conducted. BSA at different concentrations, specifically at 0.15 mg/mL, inhibited the degradation of ANs and the loss of antioxidant capacity. The results suggest that BSA has a positive effect on ANs.

Antioxidative effect of soybean milk fermented by Lactobacillus plantarum Y16 on 2, 2 –azobis (2-methylpropionamidine) dihydrochloride (ABAP)-damaged HepG2 cells

In this study, the antioxidant capacity of the Lactobacillus plantarum Y16 fermented soybean milk was investigated by different chemical antioxidant methods and ABAP-induced oxidative stress model in HepG2 cells. It was found that the L. plantarum Y16 fermented soybean milk had better radical scavenging ability for hydroxyl and DPPH radicals, and had better ferric ion reduction ability compared with unfermented soybean milk. The cellular antioxidant assay (CAA) analysis revealed that the CAA values of ethanol and water extracts of L. plantarum Y16 fermented soymilk were dose dependent. The further research showed that the ethanol and water extracts of L. plantarum Y16 fermented soybean milk protected the HepG2 cells against ABAP oxidative damage through activating Nrf2/Keap1 signaling pathway and up-regulating the expression of heme oxygenase-1(HO-1), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-PX). The results showed that the antioxidant capacity of L. plantarum Y16 fermented soybean milk was superior to that of unfermented soybean milk.

Direct and Indirect Antioxidant Effects of Selected Plant Phenolics in Cell-Based Assays.

Background: Oxidative stress is a key factor in the pathophysiology of many diseases. This study aimed to verify the antioxidant activity of selected plant phenolics in cell-based assays and determine their direct or indirect effects. Methods: The cellular antioxidant assay (CAA) assay was employed for direct scavenging assays. In the indirect approach, the influence of each test substance on the gene and protein expression and activity of selected antioxidant enzymes was observed. One assay also dealt with activation of the Nrf2-ARE pathway. The overall effect of each compound was measured using a glucose oxidative stress protection assay. Results: Among the test compounds, acteoside showed the highest direct scavenging activity and no effect on the expression of antioxidant enzymes. It increased only the activity of catalase. Diplacone was less active in direct antioxidant assays but positively affected enzyme expression and catalase activity. Morusin showed no antioxidant activity in the CAA assay. Similarly, pomiferin had only mild antioxidant activity and proved rather cytotoxic. Conclusions: Of the four selected phenolics, only acteoside and diplacone demonstrated antioxidant effects in cell-based assays.

Improving in vitro bioaccessibility and bioactivity of carnosic acid using a lecithin-based nanoemulsion system.

As a phenolic terpenoid, carnosic acid (CA) mainly exists in rosemary, which can be effectively used for the treatment of degenerative and chronic diseases by taking advantage of its health-promoting bioactivities. However, the low solubility and dissolution of CA in aqueous solutions at ambient and body temperatures result in low stability and bioaccessibility during the digestion process, which limits its application scope in the functional foods industry. In this regard, a lecithin based nanoemulsion system (CA-NE) is employed in the present work to enhance the bioaccessibility and bioactivities of CA. It is revealed that the CA-NE under investigation exhibits high loading capacity (2.80 ± 0.15%), small particle size (172.0 ± 3.5 nm) with homogeneous particle distribution (polydispersity index (PDI) of 0.231± 0.025) and high repulsive force (zeta potential = -57.2 ± 0.24 mV). More importantly, the bioaccessibility of CA-NE is improved by 2.8-fold compared to that of CA in MCT oil. In addition, the cellular antioxidant assay (CAA) and cellular uptake study of the CA-NE in HepG2 cell models demonstrate a longer endocytosis process, suggesting the well-controlled release of CA from CA-NE. Furthermore, an improved anti-inflammatory activity was evaluated via the inhibition of the pro-inflammatory cytokines, nitric oxide (NO) and TNF-α production in LPS-stimulated RAW 264.7 macrophage cells. The results clearly demonstrated a promising application of CA-NE as a functional food.