ABTS Radical Scavenging Ability Research Articles

Synthesis, Characterization, and Cytotoxicity Evaluations of Silver–Zeolite Nanocomposite

Zeolites of natural origin are materials exhibiting many positive effects on the human body. Silver-modified zeolites have already been introduced as bactericidal agents, although studies dealing with their toxicity are insufficient. This work describes the synthesis of activated and silver-loaded Bulgarian zeolite using a simple wet impregnation method. Morphological characteristics and compositions of natural zeolite, activated zeolite, and Ag-nanocomposites were studied by the X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) methods. Silver loading is approximately 13 wt. %, with mean Ag particle size around 19 nm. Analyses of the samples included antioxidant activity assays based on ABTS radical scavenging ability and in vitro cytotoxicity tests with human normal fibroblasts and three adenocarcinoma cell lines. The experiments were performed with natural, activated, and Ag-modified zeolite in comparison to two commercial food supplements. Our results indicated moderate antioxidant activity of the tested samples. Silver-modified zeolite demonstrated cytotoxic effects against both tumor cells and normal fibroblasts, but the detected levels of inhibition were stronger against the adenocarcinoma cells, suggesting anti-tumor potential. The present article indicates a new aspect of Bulgarian natural zeolite and Ag-loaded zeolite biological activity. It highlights the need for detailed toxicity evaluations of Ag-nanocomposites prior to healthcare applications.

Effect of Stevia rebaudiana stem waste extract on lipid oxidation of salted-dried Pacific saury during chilled storage

Lipid oxidation is the major form of deterioration in salted-dried fish during storage. We here studied the use of Stevia rebaudiana stem (SRS) waste for impeding lipid oxidation of salted-dried Pacific saury fillets during chilled storage. Compared with Vitamin C (VC), the SRS extract (0.2%) significantly delayed lipid oxidation of the salted-dried fish, as determined through assays of the peroxide value, conjugated diene, thiobarbituric acid reactive substances, and acid value; VC is commonly used in salted-dried products. The color results further confirmed the feasibility of the SRS extract in maintaining the quality of the salted-dried Pacific saury fillets. The antioxidant mechanism studies unveiled that the SRS extract exhibited a higher Fe2+-chelating ability than VC, whereas the extract exhibited lower DPPH and ABTS radical-scavenging abilities than VC. This indicated that the high efficacy of the SRS extract in retarding lipid oxidation may be attributable to its higher Fe2+-chelating ability. The in situ Fe2+-chelating assay conducted using confocal laser scanning microscopy further confirmed this conclusion. Potential functional phenolic compounds in the SRS extract were then profiled using the LC-MS method. The SRS waste extract can thus be applied as a natural antioxidant for delaying lipid oxidation of salted-dried fish.

Deep Eutectic Solvents as New Extraction Media for Flavonoids in Mung Bean.

Mung beans contain abundant flavonoids like vitexin and isovitexin, which contribute to their strong bioactivities, such as antioxidant effects, so efforts should focus on extracting bioactive flavonoids as well as aligning with the goal of green extraction for specific applications. Deep eutectic solvent coupled with ultrasound-assisted extraction (DES-UAE) was applied to extract flavonoids from mung beans, and eight different DESs were compared on the extraction yield. In addition, the traditional extraction method with 30% ethanol was performed as the reference. The results showed that ethylene glycol-glycolic acid achieved the highest yield among all the DESs, 1.6 times that of the reference values. Furthermore, the DES-UAE parameters were optimized as a 60 mL/g liquid-solid ratio, 30% water content in DES, 200 W ultrasonic power, 67 °C ultrasonic temperature, and 10 min extraction time, leading to the DES extract with the maximum extraction yield of 2339.45 ± 42.98 μg/g, and the significantly stronger DPPH and ABTS radical scavenging ability than the traditional extract. Therefore, employing DES and ultrasonic extraction together offers a green method for extracting flavonoids from mung beans, advancing the development and utilization of plant-derived effective components in a sustainable manner.

Effect of Cooking methods on Total Phenolics and Antioxidant activity of selected wild Edible plants

The objective of this assessment was to investigate how different cooking techniques, such as boiling and microwave cooking, impact the levels of total phenolics and antioxidant activity in commonly consumed plants like Perilla ocymoides, Clerodendrum colebrookeanum, Solanum gilo, Solanum kurzii, and Potentilla lineata, prevalent in the North-Eastern region of India. To measure the antioxidant properties of these plants, various methods were employed, including 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity, ABTS radical scavenging ability, reducing power capacity, and the assessment of total phenolic, flavonoid, and flavonol contents. The analysis revealed that the total phenolic content (TPC) of fresh vegetables ranged from 77.47 to 797.68mg/100g (expressed as gallic acid equivalent) on a dry weight basis. The total antioxidant capacity of fresh plants, measured as the percentage of inhibition, varied between 7.62% and 83.44% for DPPH, and 12.22% to 79.46% for ABTS. Boiling emerged as the cooking method causing the greatest reduction in TPC, resulting in a decline ranging from 10.90% in P. lineata up to 25.66% in S. kurzii when calculated on a dry weight basis. Conversely, microwave cooking led to an enhancement in TPC, with an increase ranging from 2.20% to 11.80%. Furthermore, the impact of boiling on DPPH radical scavenging activities was notable, causing a decrease between 8.44% and 43.30%, and for ABTS radical scavenging activities, the reduction ranged from 10.24% to 34.45%. In contrast, microwave cooking had a positive effect on DPPH and ABTS radical scavenging activities, increasing them by 9.39% to 46.32%, and 8.49% to 46.39%, respectively, across the studied plants. In conclusion, the results suggest that microwave cooking stands out as the optimal method for preserving and even increasing the concentration of polyphenols and antioxidants in these plants. Conversely, boiling exhibited the least desirable outcomes in terms of retaining these beneficial components.

Fabrication and characterisation of pea protein isolate‐chlorogenic acid nanoparticles

SummaryChlorogenic acid (CA) is a natural antioxidant with multiple biological activities, but its stability is poor. In this article, CA‐load pea protein nanoparticles (PPCNPs) were constructed by an anti‐solvent method to enhance CA stability and characterised by multiple technologies. The results exhibited that the particle size of PPCNPs ranged from 211.62 to 429.79 nm, and the zeta potential ranged from −41.21 to −35.85 mV. PPCNPs had the highest encapsulation efficiency (61.2%) at the CA/pea protein isolate (PPI) mass ratio of 1:20. The loading capacity increased with the ratio of CA/PPI ranging from 1.3% to 3.8%. SEM showed that the nanoparticle surface was an irregular lamellar structure. FTIR showed that O–H and C–H functional group interactions occurred between CA and PPI. DSC results showed that CA was encapsulated in PPCNPs with an amorphous structure. During in vitro digestion, the ABTS radical scavenging ability and retention ratio of CA in PPCNPs was higher than that of free CA. Moreover, PPCNPs increased the bio‐accessibility of CA in vitro by 7.75%, compared with unencapsulated CA. These results suggested that PPCNPs constructed by the anti‐solvent method can reduce the degradation of CA and improve the biological activity of CA.

Effect of lactic acid bacteria co-fermentation on antioxidant activity and metabolomic profiles of a juice made from wolfberry and longan

Lactic acid bacteria (LAB) fermentation is frequently employed to improve the nutritional, functional, and sensory characteristics of foods. Our study explored the effects of co-fermentation with Lacticaseibacillus paracasei ZH8 and Lactococcus lactis subsp. lactis YM313 on the physicochemical properties, antioxidant activity, and metabolomic profiles of wolfberry–longan juice (WLJ). Fermentation was carried out at 35 °C for 15 h. The results suggest that WLJ is a favorable substrate for LAB growth, reaching a total viable count exceeding 8 log CFU/mL after fermentation. LAB fermentation increased acidity, reduced the sugar content, and significantly impacted the juice color. The total phenolic and flavonoid contents of the WLJ and the antioxidant capacities based on 2,2-diphenyl-1-picrylhydrazyl (DPPH), ABTS radical scavenging abilities and FRAP were significantly improved by LAB fermentation. Nontargeted metabolomics analysis suggested that the contents of small molecule substances in WLJ were considerably affected by LAB fermentation. A total of 374 differential metabolites were identified in the juice before and after fermentation, with 193 significantly upregulated metabolites and 181 siginificantly downregulated metabolites. The regulation of metabolites is important for improving the flavor and functions of juices, such as L-eucylproline, Isovitexin, Netivudine, 3-Phenyllactic acid, vanillin, and ethyl maltol, ect. This study provides a theoretical foundation for developing plant-based foods fermented with LAB.

EFFECT OF COOKING METHODS ON TOTAL PHENOLICS AND ANTIOXIDANT ACTIVITY OF SELECTED WILD EDIBLE PLANTS

Objective: The target of this appraisal was to explore the impacts of various cooking techniques, for example, boiling and microwave cooking on total phenolics and antioxidant activity of Zanthoxylum acanthopodium, Viburnum foetidum, Houttuynia cordata, Sonchus arvensis and Oenanthe linearis, widely consumed by the common individuals of the North-Eastern area of India. Methods: The antioxidant activities of the plants were determined by using 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity, ABTS radical scavenging ability, reducing power capacity, estimation of total phenolic content, flavonoid content and flavonol content. Results: Total phenolics content (TPC) of fresh vegetables ranged from 108.28 to 253.99 mg/100 g (as gallic acid equivalent) on a dry weight basis. Total antioxidant capacity of fresh plants (IC50 mg dry extract) determined by DPPH and ABTS ranged from 0.37-1.23 and 0.29-0.89, respectively. Boiling caused the highest losses of TPC, resulting in a reduction of the TPC on dry weight (DW) basis ranging from 9.37% in O. linearis up to 25.97% in Z. acanthopodium whereas microwave cooking enhanced TPC ranging from 4.09% to 10.38%. Similarly, boiling treatment decreased the DPPH radical scavenging activities ranging from 10.65 to 29.77% and ABTS radical scavenging activities ranging from 5.88-16.35%, whereas microwave cooking increased the DPPH and ABTS radical scavenging activities ranging from 8.02-24.20% and 9.86 to 19.70% respectively, in the studied plants. Conclusion: The results suggest that the best cooking method for increasing the concentration of polyphenols and antioxidants was microwave cooking while boiling was the least recommended method.

Structural characterization and antioxidant activity of pectic polysaccharides from Veronica peregrina L.

Pectins are a class of acidic polysaccharides with complex structures. Different pectin molecules are composed of different domains, which have an important impact on their biological activity. This study aimed to determine the structural features and the antioxidant activities of the pectic polysaccharides isolated from Veronica peregrina L. The polysaccharide was isolated from Veronica peregrina L by water extraction and fractionated by ion exchange chromatography and gel permeation chromatography. The structure features of the pectic polysaccharides were determined by Fourier transforminfrared spectroscopy (FT-IR) and Nuclear magnetic resonance (NMR). The antioxidant activities was evaluated by the DPPH, OH and ABTS radical scavenging ability. WVPP-A2b and WVPP-A3b, with molecular weights of 48.7 × 104 and 77.6 × 104 kDa, respectively, contained homogalacturonan (HG), rhamnogalacturonan I (RG-I), and rhamnogalacturonan II (RG-II) domains with a mass ratio of 2.08:2.64:1.00 and 3.87:4.65:1:00, respectively. The RG-I domain contained an arabinogalactan II backbone and arabinans consisting of t-Araf, (1→5)-α-Araf, and (1→3,5)-α-Araf. WVPP-A3b also contained short chains consisting of the [t-Araf-(1→5)-α-Araf-(1→] structural unit. WVPP-A3b showed stronger ability to scavenge DPPH, hydroxyl, and ABTS radicals, which was potentially associated with its high content of galacturonic acid and presence of the HG domain. The results provide information for enhancing knowledge of the structureactivity relationship of pectic polysaccharides from V. peregrina and their potential application in the healthcare food field.

한국 전통재래식 간장과 개량식 간장의 이화학적 품질 특성 및 항산화 활성 비교

In this study, we compared and analyzed the physicochemical quality characteristics and antioxidant activity of Korean traditional Ganjang made from 100% Korean Meju in six provinces in Korea The Ganjang was aged for three years after manufacturing with Korean sun-dried salt of traditional Ganjang AS (Gangwon-do), BS (Gyeonggi-do), CS (Chungcheong-do), DS (Jeolla-do), ES (Gyeongsang-do), FS (Jeju-do), GS (Improved brewed Ganjang marketed by major corporations) and HS (acid hydrolyzed Ganjang). The moisture content was 64.67%∼73.39%, with HS (acid hydrolyzed Ganjang) the highest, and GS (brewed Ganjang) the lowest. The ash content was 13.14%-25.49%, and all samples of Korean traditional soy sauce were higher than those of GS and HS soy sauce. The crude protein content was 3.20% to 6.80% for six types of Korean traditional Ganjang, and 10.97% for GS and 5.54% for HS. The content of crude fat was not measured in the samples of GS and HS. The pH was in the range of 4.19 to 4.96, and all samples showed similar values. The salinity was measured at 15.98% in GS and 14.65% in HS, which is lower than that of Korean traditional Ganjang. The sugar content was the highest at 40.63 Brix% and the lowest at 26.70 Brix%. The acidity of Ganjang was 4.20∼5.85 in Korean traditional Ganjang, showing a difference between samples, and HS 1.86, which was the lowest. The color values lightness of Ganjang was higher in six types of traditional Korean Ganjang than GS and HS. The total phenol contents, DPPH radical scavenging ability, and ABTS radical scavenging ability were higher than those of GS and HS samples in all samples of Korean traditional Ganjang.

Phytochemical profile, antioxidant, cytotoxic and anti-inflammatory activities of stem bark extract and fractions of Ailanthus excelsa Roxb.: In vitro, in vivo and in silico approaches

This study aimed to assess the phytochemical composition, in vitro antioxidant, cytotoxicity, and in vivo anti-inflammatory activities of the methanolic extract of Ailanthus excelsa (Simaroubaceae) stem bark and its fractions. Quantitative phytochemical analysis revealed that methanolic extract and all fractions contained a high level of flavonoids (20.40–22.91 mg/g QE), phenolics (1.72–7.41 mg/g GAE), saponins (33.28–51.87 mg/g DE), and alkaloids (0.21–0.33 mg/g AE). The antioxidant potential was evaluated in vitro using a range of assays, i.e., DPPH•, ABTS radical scavenging ability, and total antioxidant capacity. The chloroform and ethyl acetate fractions showed stronger antioxidant activity than the methanol extract. In vitro cytotoxic activity was investigated in three human tumor cell lines (A-549, MCF7 and HepG2) using the SRB assay. In addition, the in vivo anti-inflammatory effect was assessed by carrageenan-induced paw edema in rats. The chloroform fraction showed a more pronounced effect by effectively controlling the growth with the lowest GI50 and TGI concentrations. The human lung cancer cell line (A-549) was found to be more sensitive to the chloroform fraction. Furthermore, the chloroform fraction exhibited significant anti-inflammatory activity at a dose of 200 mg/kg in the latter phase of inflammation. Besides, methanol extract and ethyl acetate fraction revealed a significant cytotoxic and anti-inflammatory effects. The chloroform fraction of stem bark showed a strong anti-inflammatory effect in experimental animals and significant COX-2 inhibitory potential in the in vitro experiments. GC-MS analysis of chloroform fraction identified the phytochemicals like caftaric acid, 3,4-dihydroxy phenylacetic acid, arachidonic acid, cinnamic acid, 3-hydroxyphenylvaleric acid, caffeic acid, hexadeconoic acid, and oleanolic acid. The in-silico results suggest that identified compounds have better affinity towards the selected targets, viz. the BAX protein (PDB ID: 1F16), p53-binding protein Mdm-2 (PDB ID: 1YCR), and topoisomerase II (PDB ID: 1QZR). Amongst all, caftaric acid exhibited the best binding affinity for all three targets. Thus, it can be concluded that caftaric acid in combination with other phenolic compounds, might be responsible for the studied activity. Additional in vivo and in vitro studies are required to establish their exact molecular mechanisms and consider them as lead molecules in developing of valuable drugs for treating oxidative stress-induced disorders, cancers, and inflammations.

In Vitro Fermentation Characteristics of Pine Needles (Pinus densiflora) as Feed Additive

In this study, the fermentation characteristics of pine needles were investigated for the first time and the possibility of using them as plant-derived feed additives was confirmed. Four types of fermented pine needle were prepared: (1) natural fermentation (CON); (2) Lactobacillus plantarum SK4315 fermentation (LPF); (3) Saccharomyces cerevisiae SK3587 fermentation (SCF); and (4) co-culture fermentation (CCF). Fermentation lasted 48 h, and samples were taken at 4-h intervals until 12 h, then at 24 and 48 h. As analysis items, fermentation characteristics, antibacterial, antioxidant, and enzymatic activities were investigated. As a result, all pine needle cultures were fermented with changes in the number of viable cells and pH. LPF inhibited the growth of the most pathogens, and the activity became stronger with fermentation. Total polyphenol content (TPC) was the highest in the 48 h SCF and LPF samples, ABTS radical scavenging ability and intracellular antioxidant activity were higher in SCF. Enzymatic activities were different depending on each pine needle culture medium and the fermentation time. In summary, all pine needle cultures were normally fermented, and as fermentation progressed, LPF strengthened antibacterial activity and SCF strengthened antioxidant activity. This study confirmed the potential of fermented pine needles as a feed additive, showing an enhancement of biological activity.

Utilization of feather keratin waste to antioxidant and migration-enhancer peptides by Bacillus licheniformis 8-4.

Feathers are keratin-rich byproducts of poultry processing, but those are often frequently abandoned as garbage and thus polluting the environment. Therefore, the study focused on the efficient biodegradation, bioactivity, and high-value application of feather keratin. Feather-degrading bacteria were identified, and the degradation properties were characterized. DPPH (1,1-Diphenyl-2-picrylhydrazyl radical) and ABTS (2,2'-Azino-bis (3-ethylbenzthiazoline-6-sulfonic acid))radical scavenging assays, cytotoxicity assays, intracellular reactive oxygen scavenging assays, and cell migration assays were used to examine the biological activities of the feather keratin hydrolysis peptides (FKHPs). The results showed that we screened a feather-degrading strain of Bacillus licheniformis 8-4, which achieved complete degradation of 2% (w/v) feathers within 48h. Notably, the feather fermentation broth was particularly high in FKHPs, which exhibited good DPPH and ABTS radical scavenging ability. Further studies revealed that FKHPs had both the ability to scavenge H2O2-induced ROS from HaCat cells and the ability to promote HaCat cell migration, while remaining non-toxic. The effective feather-degrading ability of B. licheniformis 8-4 allowed for the fermentation of feather medium to yield active peptides that were both antioxidants and cell-migration enhancers.

Studies of Antioxidant and Cytotoxic Activity in Ready-to-Drink Wild Ganoderma Teas: An In Vitro Approach.

Ganoderma is a medicinally important mushroom and has been used since ancient times. However, mostly G. lucidum has been used for therapeutic purposes, in form of tea, dietary and drug supplements but other species of Ganoderma are still remaining underexploited. This study is the first approach to valorize Ganoderma teas prepared from different wild species of Ganoderma other than G. lucidum with respect to both phytochemically and therapeutically through investigation of their phytochemical, carbohydrate contents and exploring their antioxidant activity. Phytochemical contents such as phenol and flavonoids were quantified using spectrophotometry methods. The carbohydrate content of the teas was estimated by phenol sulphuric acid method. The biochemical analysis revealed the teas contained a notable amount of phenolic compounds ranging from 19.15 to 40.2 µg GAE/mg of extract and also showed significant content of flavonoids. Further, antioxidant potential in terms of DPPH and ABTS radical scavenging ability and total antioxidant capacity was also evaluated. According to the results, G. resinaceum tea showed better potential in scavenging DPPH (EC50 36 ug/mL) and ABTS radicals (EC50 3 9 ug/mL) whereas the least effect was shown for the tea of G. ahmedi. Therefore, tea showing the best results, i.e. G. resinaceum tea, was also analyzed for cytotoxicity on breast cancer cells. It was found that the tea made from G. resinaceum inhibited cellular growth and proliferation in a dose-dependent manner with maximum growth inhibition (61%) observed at the highest concentration of 2.3 mg/mL. The presence of a greater quantity of carbohydrates in G. resinaceum tea also justified the remarkable anticancer potential of the tea. Overall, our findings indicated that a few wild species of Ganoderma other than G. lucidum have great potential to be valued as a healthy beverage with immense therapeutic benefits.

Interaction of α‐lactalbumin with dihydromyricetin and its application in nano‐emulsion

SummaryThe non‐covalent interaction between α‐lactalbumin (α‐La) and dihydromyricetin (DMY) was systematically revealed based on spectrofluorimetry and molecular docking method, and the potential application of their complex as an emulsifier in nano‐emulsion was evaluated. The results showed that DMY and α‐La could form a non‐covalent complex, which led to the static fluorescence quenching of α‐La, and their complexation was driven by hydrogen bonding and van der Waals force, causing the changes in the microenvironment around the tryptophan and tyrosine residues of α‐La, which was consistent with molecular docking analysis. The increase of the proportion of DMY in the complex could gradually improve the ability of the complex to reduce the oil/water interfacial tension and its ABTS radical scavenging ability. The stability and β‐carotene protective effect of nano‐emulsion developed by the complex were superior to those of nano‐emulsion stabilised by α‐La, which were positively correlated with the DMY concentration in the complex.

Physicochemical properties and protective effects on UVA-induced photoaging in Hs68 cells of Pleurotus ostreatus polysaccharides by fractional precipitation

The development of natural ingredients protecting skin from UVA-induced photoaging is widely expected. The present study investigated the physicochemical properties, antioxidant, moisturizing, collagenase and elastase inhibitory activities, and protective effect on UVA-induced photoaging in Hs68 cells of Pleurotus ostreatus polysaccharides (POPs). POP-40, POP-60, and POP-80 were extracted by gradient precipitation of 40 %, 60 %, and 80 % ethanol, which could be prepared in large quantities. The results showed that POPs had good DPPH and ABTS radical scavenging abilities, water retention capacity, and collagenase and elastase inhibition effects. POP-80 had the best efficacy. Further determined the anti-inflammatory and antisenescence activities of POPs in Hs68 cells. The results indicated that after UVA irradiation, the contents of ROS, senescent cells, NF-κB activity, and proinflammatory cytokines increased in Hs68 cells. However, cells pretreated with 50 μg/mL POPs significantly decreased the contents of ROS and the number of senescent cells, reduced NF-κB activity, and inhibited IL-6 and TNF-α production. There was no significant difference in reducing the accumulation of ROS and senescent cells between POP-80 and the common anti-inflammatory substance quercetin. The results suggested that POP-80 may be potential cosmeceutical ingredients as it can protect Hs68 cells from photodamage.

In Vitro Digestion and Colonic Fermentation of UHT Treated Faba Protein Emulsions: Effects of Enzymatic Hydrolysis and Thermal Processing on Proteins and Phenolics.

Faba bean (Vicia faba L.) protein is a new plant protein alternative source with high nutrient content especially protein and phenolic compounds. The present study investigated physicochemical properties, phenolic content, antioxidant potential, and short chain fatty acids (SCFAs) production during in vitro digestion and colonic fermentation of faba bean hydrolysates and oil-in-water (O/W) emulsions. Results indicate that the enzymic hydrolysates of faba proteins exhibited higher protein solubility, increased electronegativity, and decreased surface hydrophobicity than native faba protein. O/W emulsions showed improved colloidal stability for the faba protein hydrolysates after ultra-high temperature processing (UHT). Furthermore, UHT processing preserved total phenolic content, DPPH and ABTS radical scavenging abilities while decreasing total flavonoid content and ferric reducing power. Besides, the release of phenolic compounds in faba bean hydrolysates (FBH) and emulsions (FBE) improved after intestinal digestion by 0.44 mg GAE/g and 0.55 mg GAE/g, respectively. For colonic fermentation, FBH demonstrated an approximately 10 mg TE/g higher ABTS value than FBE (106.45 mg TE/g). Total SCFAs production of both FBH and FBE was only 0.03 mM. The treatment of FBH with 30 min enzymatic hydrolysis displayed relatively higher antioxidant capacities and SCFAs production, indicating its potential to bring more benefits to gut health. Overall, this study showed that enzymic hydrolysis of faba proteins not only improved the colloidal emulsion stability, but also released antioxidant capacity during in vitro digestibility and colonic fermentation. Colonic fermentation metabolites (SCFAs) were related to the degree of hydrolysis for both FBH and FBE. Additional studies are required to further elucidate and differentiate the role of phenolics during faba protein processing and digestion stages in comparison to contributions of peptides, amino acids and microelements to digestion rates, antioxidant capacities and colonial SCFA production.

Three novel antioxidant peptides isolated from C-phycocyanin against H2O2-induced oxidative stress in zebrafish via Nrf2 signaling pathway

BackgroundC-phycocyanin (C-PC), a phycobiliprotein from Spirulina platensis, has been confirmed to be an effective antioxidant. Duing to the large molecular weight protein, C-PC is hardly absorbed in the human gut and easy coagulates into lumps. In light of this, highly pure, easy absorption, and small molecular weight polypeptides has won the attention in the recent past. However, there are few studies on the C-PC bioactive peptides. Thus, the objective of this study was find natural multifunctional antioxidant peptides from C-PC and demonstrate their mechanisms.MethodIn this study, novel antioxidant peptides from pancreatin hydrolysate of C-PC were isolated and purified by using a multi-bioassay-guided method. The DPPH and ABTS radical scavenging in vitro and antioxidant zebrafish model in vivo were used to evaluate the antioxidant activities. Furthermore, the underlying molecular mechanisms of these peptides were investigated by measuring the level of ROS, MDA, SOD, CAT and gene expression in Nrf2 signaling pathway.ResultsTotal three novel active peptides, MHLWAAK (Met-His-Leu-Trp-Ala-Ala-Lys), MAQAAEYYR (Met-Ala-Gln-Ala-Ala-Glu-Tyr-Tyr-Arg), and MDYYFEER (Met-ASP-Tyr-Tyr-Phe-Glu-Glu-Arg) were isolated and purified from pancreatin hydrolysate of C-PC. These synthesized peptides displayed high DPPH and ABTS radical scavenging ability. In addition, in a zebrafish model, the three peptides significantly protected zebrafish embryos from H2O2-induced oxidative injury without toxicity by inhibiting ROS generation, preventing MDA formation, and upregulating the activities of SOD and CAT. Further experiments showed that these peptides could significantly regulated oxidative stress via activating the Nrf2 signaling pathway.ConclusionThis study indicates that the antioxidant peptides from C-PC could serve as powerful antioxidants for preventing and treating various diseases associated with oxidative stress.

New Biological and Chemical Evidences of Two Lamiaceae Species (Thymbra capitata and Thymus sipyleus subsp. rosulans): In Vitro, In Silico and Ex Vivo Approaches.

In this study, the methanolic and infusion extracts of two species, Thymbra capitata and Thymus sipyleus subsp. rosulans, were tested for their chemical composition and biological abilities (antioxidant, enzyme inhibitory and anti-inflammatory effects). The extracts yielded total phenolic and flavonoid contents in the range of 83.43-127.52 mg GAE/g and 9.41-46.34 mg RE/g, respectively. HPLC analysis revealed rosmarinic acid to be a major component of the studied extracts (15.85-26.43%). The best ABTS radical scavenging ability was observed in the methanol extract of T. capitata with 379.11 mg TE/g, followed by in the methanol extract of T. sipylus (360.93 mg TE/g). In the CUPRAC assay, the highest reducing ability was also found in the methanol extract of T. capitata with 802.22 mg TE/g. The phosphomolybdenum ability ranged from 2.39 to 3.61 mmol TE/g. In terms of tyrosinase inhibitory effects, the tested methanol extracts (83.18-89.66 mg KAE/g) were higher than the tested water extracts (18.74-19.11 mg KAE/g). Regarding the BChE inhibitory effects, the methanol extracts were active on the enzyme while the water extracts showed no inhibitory effect on it. Overall, the methanolic extracts showed better enzyme inhibition compared to the infusion extracts. Molecular docking also showed the selected exhibited potential binding affinities with all enzymes, with a preference for cholinesterases. Additionally, the extracts were effective in attenuating the LPS-induced increase in COX-2 and IL-6 gene expression in isolated colon, thus indicating promising anti-inflammatory effects. The preliminary results of this study suggest that these species are good natural sources of antioxidants and also provide some scope as enzyme inhibitors, most likely due to their bioactive contents such as phenolic acids, and thus can be exploited for different applications related to health promotion and disease prevention.

The structural and functional properties of dietary fibre extracts obtained from highland barley bran through different steam explosion-assisted treatments

The effects of steam explosion (SE)-assisted ultrasound (SEU), citric acid (SEC), sodium hydroxide (SEA), and cellulase (SEE) treatment on the properties of soluble dietary fibre (SDFP) extracted from highland barley bran were analysed. The results showed that SE pretreatment combined with other methods effectively improves the SDFP yield. The highest yield of SDF (20.01%) was obtained through SEA treatment. SEU-SDFP had a loose and porous structure, whereas the surface of SEC-SDFP and SEA-SDFP presented a complicated and dense texture. Although SE pretreatment reduced the thermal stability of SDFP, SEC and SEE treatment maintained its thermal stability. Furthermore, SEU-SDFP exhibited the highest water and oil holding capacities, and cholesterol and nitrite ion adsorption capacities. SEE-SDFP exhibited the best DPPH and ABTS radical scavenging abilities. In summary, four SE-assisted extraction methods had different advantages, and highland barley bran SDF can be considered as a potential functional additive in the food industry.

Soy protein–phlorizin conjugate prepared by tyrosinase catalysis: Identification of covalent binding sites and alterations in protein structure and functionality

Tyrosinase-catalyzed synthesis of soy 7S/11S–phlorizin conjugates was performed, and the reaction sites, conformation alterations and functional properties of complexes were evaluated using proteomic, in combination with multispectral technologies. Phlorizin was conjugated to 7S/11S primarily via residues of Lys, Cys, His and Arg residues. The phlorizin binding equivalents and decreased contents of free and total sulfhydryl groups and free amino groups confirmed the covalent interaction in the 7S/11S–phlorizin complexes. Conjugation with phlorizin promoted the conversion of α-helix to β-sheet and β-turn, with simultaneous transformation of the microenvironments around Trp and Tyr residues to hydrophilic and hydrophobic microenvironments, respectively, and lowering of the surface hydrophobicity of 7S/11S. The DPPH and ABTS radical scavenging abilities and α-glucosidase inhibitory activities of 7S/11S were increased by three–, two– and three–fold after the covalent binding of phlorizin. The study provided an ideal tyrosinase-catalyzed approach to fabricate custom–tailored nutritional soy protein–polyphenol products.