Chelate Iron Ions Research Articles

Chemical Composition and Antioxidant Capacity of Lepidium sativum Seeds from Four Regions of Morocco.

Lepidium sativum seeds (LSS) from four regions of Morocco have been analyzed for their total chemical composition and antioxidant activities. In the seeds of this plant, the moisture content and yield were, respectively, 9.24–9.88% and 19.13–19.94% of dry weight. Chemical analysis of the seeds revealed amounts of fatty acids, sterols, and tocopherols. The most important fatty acids are linolenic acid (33%) and oleic acid (23%). The main sterol is β-sitosterol (50%); the vegetable oil of Lepidium sativum revealed an amount of tocopherol (∼1500–1900 mg/kg) with dominance of γ-tocopherol. The Folin–Ciocalteu trial evaluated the total phenolic compound, DPPH radical scavenging, ABTS, and chelated iron ions. FRAP measured antioxidant potency. Results indicated that methanol extract from Lepidium sativum was a more potent reducing agent and radical scavenger than ethanol extract. Changes in the total phenolic content and antioxidant capacity of Lepidium sativum in four different regions grown under normal conditions were evaluated. The antioxidant activity of different extracts was found to correlate significantly with their total phenolic content. These results suggest that Lepidium sativum seeds could be used in food supplement preparations or as a food additive, for caloric gain or for protecting against oxidation in nutrient products.

Silver-coated zero-valent iron nanoparticles enhance cancer therapy in mice through lysosome-dependent dual programed cell death pathways: triggering simultaneous apoptosis and autophagy only in cancerous cells.

In this study, we demonstrated that zero-valent iron (ZVI), which is widely used to remediate environmental contamination through the production of high-energy reactive oxygen species (ROS), exhibited differential cytotoxicity in cancerous cells and nonmalignant cells. Nanoparticles (NPs) with different shells exhibited distinct potencies against cancerous cells, which depended on their iron-to-oxygen ratios. Silver-coated ZVI NPs (ZVI@Ag) had the highest potency among synthesized ZVI NPs, and they simultaneously exhibited adequate biocompatibility with nonmalignant keratinocytes. The assessment of the intracellular dynamics of iron species revealed that the uptake of ZVI@Ag was similar between cancerous cells and nonmalignant cells during the first 2 h; however, only cancerous cells rapidly converted NPs into iron ions and generated large amounts of intracellular ROS, which was followed by apoptosis and autophagy induction. The aforementioned processes were prevented in the presence of iron ion chelators or by preoxidizing NPs before administration. Neutralization of lysosomal pH effectively reduced ZVI@Ag NP-induced programmed cell death. In the xenograft mouse model, cancer growth was significantly inhibited by a single dose of systematically administered NPs without significant weight loss in animals.

Assessment of Streptococcus salivarius sp thermophiles Antioxidant Efficiency and its Role in Reducing Paracetamol Hepatotoxicity.

Background: Probiotics have attracted a great attention aiming to develop natural non-toxic antioxidants, because of their role in decreasing the risk of reactive oxygen species [ROS] accumulation.Objectives: The purpose of this study was to assess the antioxidant activity of a probiotic Streptococcus salivarius ssp thermophillus [St.sa] and to evaluate its protective effect against the oxidative stress induced by a toxic dose of paracetamol in Wistar rats.Materials and Methods: Several assays were used to investigate the in vitro antioxidant capacity of the strain. To evaluate the protective effect against oxidative stress induced by paracetamol in liver, hepatic marker enzymes, the antioxidant enzyme activities, malondialdehyde [MDA] and glutathione [GSH] content in liver tissues were investigated.Results: The strain has shown a considerable ability to scavenge DPPH free radical [89.43%],a good resistance to hydroxyl radicals [47%], a considerable ability to chelate iron ions [33.21%] and a good inhibitory effect against plasma lipid peroxidation [54.36%]. Significant changes in liver function tests, antioxidant enzyme activities, MDA and GSH levels in paracetamol treated group were obtained compared to control group. Pretreatment with probiotic removed significantly the inhibition of antioxidant enzymes and suppressed MDA increase and GSH depletion. The analysis of the level of mRNA expression of antioxidant enzymes showed no significant differences in the expression of the enzymes in treated or non-treated groups.Conclusion: This finding emphasizes the protective role of probiotics against ROS generated during the treatment with paracetamol

Effects and mechanisms of lincomycin degradation by six promoters in the mZVI/H2O2 systems

In this paper, the effects of lincomycin (LCM) degradation by six typical promoters such as tea polyphenols (TP), oxalic acid (OA), ethylenediaminetetraacetic acid disodium (EDTA), hydroxylamine hydrochloride (HA), sodium tripolyphosphate (TPP) and ascorbic acid (AA) on the Fe0/H2O2 system based on microscale zero valent iron (mZVI) were compared through batches of experiments. The degradation effects of promoters on the Fe0/H2O2 system in 90 min showed significant promotion (OA, AA and HA), moderate promotion (TP) and inhibition (EDTA, TPP), respectively. Moreover, this result was very consistent with the results of •OH and ORP. First, by studying the effects of each promoter on the pH value and the iron leaching of the Fe0/H2O2 system, it was preliminarily proved that the main reason for the enhancement of Fenton-like degradation of OA, HA and AA is to lower the pH and thus promote iron leaching. Then, through comparative experiments of reducing and chelating abilities of six promoters, it was proved that TP promoted the Fenton-like degradation mainly by reduction and chelation without significantly changing the pH of the system. Although EDTA and TPP have strong chelating ability and ability to promote iron leaching, respectively, they caused the pH to be too high, which inhibited the reaction. The results show that lowering the pH of system, promoting iron leaching, reducing ferric iron and chelating iron ions to avoid the formation of iron sludge are the main mechanisms of the current Fenton-like promoters. Moreover, the combination of multiple promotion methods can better adapt to different reaction conditions.

Protoporphyrin IX tracer fluorescence modulation for improved brain tumor cell lines visualization

Fluorescence image guided surgical resection (FIGR) of high grade gliomas (HGGs) takes advantage of the accumulation of the tracer protoporphyrin IX (PpIX) in glioma cells following administration of 5-aminolevulinic acid (5-ALA). Occasionally, PpIX fluorescence intensity may be insufficient, thus compromising the efficacy and precision of the surgical intervention. The cause for the signal variation is unclear and strategies to improve the intensity of PpIX fluorescence are considered necessary. We have previously shown that differential expression of the epidermal growth factor receptor in glioblastoma cells affects PpIX fluorescence. Herein, we investigated other factors impairing PpIX accumulation and pharmacological treatments able to enhance PpIX fluorescence in glioblastoma cells displaying lower signal. In the present study we demonstrate that presence of serum in cell culture medium and differences in cellular confluence can negatively influence PpIX accumulation in U87 cell lines.We hypothesized that PpIX fluorescence intensity results from the interplay between the metabolic clearance of PpIX mediated by ferrochelatase and heme oxygenase-1 and the cellular efflux of PpIX through the ATP-binding cassette subfamily G member 2 (ABCG2). Based on the availability of compounds targeting these proteins and inhibiting them, in this study we used modulators such as genistein, an isoflavone able to inhibit ABCG2; deferoxamine, which chelate iron ions impairing FECH activity and tin protoporphyrin IX (SnPP), the specific HO-1 inhibitor. Finally, we showed the efficacy of a precisely tuned pharmacological treatment in increasing PpIX accumulation and consequently fluorescence in glioblastoma cells. This strategy may translate in more sensitive tracing of tumor cells in-vivo and improved FIGR of HGGs and possibly low grade gliomas (LGGs).

Fe2+/Fe3+ Ions Chelated with Ultrasmall Polydopamine Nanoparticles Induce Ferroptosis for Cancer Therapy.

Ferroptosis, a promising mechanism of killing cancer cells, has become a research hotspot in cancer therapy. Besides, advantages of polymeric nanomaterials in improving anticancer efficacy and reducing side effect are widely accepted. In this work, based on the property of polypodamine to chelate metal ions, ultrasmall poly(ethylene glycol)-modified polydopamine nanoparticles, (UPDA-PEG)@Fe2+/3+ nanoparticles, a novel ferroptosis agent, was rationally designed by chelating iron ions on ultrasmall polydopamine nanoparticles modified by PEG. This treatment led to a bigger specific surface area, which could support more reactive sites to chelate large number of iron ions, which is beneficial for exploring the detailed mechanism of ferroptosis-induced tumor cell death by iron ions. Also, the pH-dependent release of iron ions can reach approximately 70% at pH 5.0, providing the advantage of application in tumor microenvironment. The in vitro tests showed that the as-prepared NPs exhibit an effective anticancer effect on tumor cells including 4T1 and U87MG cells, yet ferric ions show a stronger ability of killing cancer cells than ferrous ions. Differences between ferrous ions and ferric ions in the ferroptosis pathway were monitored by the change of marker, including reactive oxygen species (ROS), glutathione peroxidase 4, and lipid peroxide (LPO), as well as the promoter and inhibitor of ferroptosis pathway. UPDA-PEG@Fe2+ nanoparticles induce ferroptosis that depends more on ROS; however, a more LPO-dependent ferroptosis is induced by UPDA-PEG@Fe3+ nanoparticles. Additionally, the in vivo studies using tumor-bearing Balb/c mice demonstrated that the as-prepared NPs could significantly inhibit tumor progression. UPDA-PEG@Fe2+/3+ nanoparticles reported herein represent the nanoparticles related to iron ions for chemotherapy against cancer through the ferroptosis pathway.

Design, synthesis and biological evaluation of hydroxypyridinone-coumarin hybrids as multimodal monoamine oxidase B inhibitors and iron chelates against Alzheimer's disease

A series of hybrids of hydroxypyridinone and coumarin were rationally designed, synthesized and biologically evaluated for their iron ion chelating and MAO-B inhibitory activities. Most of the compounds displayed excellent iron ion chelating effects and moderate to good anti-MAO-B activities. Compound 27a exhibited the most potent activity against MAO-B, with an IC50 value of 14.7 nM. Importantly, 27a showed good U251 cell protective effect and significantly ameliorated the cognitive dysfunction of scopolamine-induced AD mice. Moreover, molecular docking was performed to elucidate the probable ligand-receptor interaction, and the structure-activity relationships were also summarized.

Composition and In Vitro Effects of Cultivars of Humulus lupulus L. Hops on Cholinesterase Activity and Microbial Growth.

Common hop (Humulus lupulus L.) has significant health-promoting properties. Hop cones contain resins, essential oils, proteins, polyphenols, lipids, waxes, and cellulose. Hop extracts include bioactive compounds such as polyphenolic compounds (phenolic acids, and flavonols), and chlorophylls. The aim of this study was to compare the pro-health potential of hop cone extracts obtained from three cultivars (Magnum, Lubelski, and Marynka). The results showed that the cones of Magnum cultivar demonstrated the highest biological activity. The sum of phenolic acids and flavonols in ethanol extract was the highest for this variety and was equal 4903.5 µg/g dw. Ethanol extracts of Magnum cultivars showed the highest degree of iron ion chelation (55.43–88.76%) as well as the activity against 1,1-diphenyl-2-picrylhydrazyl radical (4.75 mmol Tx/g dw). Hop cone extracts as cholinesterase inhibitors showed high potential for aqueous variants. In terms of antimicrobial activity, all investigated extracts demonstrated strong inhibition against Staphylococcus aureus and Staphylococcus epidermidis, with the Magnum cultivar showing the strongest inhibition. Owing to the biofunctional features of hop cone, it can be concluded that it is an attractive raw material with pro-health potential that can be used much more widely in food technology. However, it should be noted that toxicological tests and in vitro tests must be carried out before the raw material is used in food production.

Lactobacillus gasseri from human milk with probiotic potential and some technological properties

In the current study, Lactobacillus gasseri MA-4 strain from human breast milk was evaluated for its probiotic potential and some technological properties. The strain was also evaluated for its virulency. The antimicrobial activity was tested against a wide range of clinical-human and food pathogenic bacteria, Candida species and various fish pathogens. High tolerance was observed by MA-4 strain for some essential parameters such as low pH, bile salts, artificial stomach and small intestine fluids conditions. The autoaggregation and coaggregation abilities of the strain were recorded as 95% and 45–55% respectively. The nisin sensitivity against nine different nisin concentrations (1.25–150 -μg/mL) was only observed at 100 and 150μg/mL. The strain exhibited high resistance to sodium benzoate (0.1% w/v), a commonly used food preservative. The supernatant of the strain showed high cholesterol assimilation ability with 75.66% at the 1% bile concentration. DPPH free radical reducing and the iron ion chelating activity of MA-4 strain were determined as 39.20% and 15.60% respectively. Amylase and β-1,3–1,4-glucanase (lichenase) enzymes activities were also obtained qualitatively. Consequently, MA-4 strain may be considered as a good candidate for probiotic cultures, biotherapeutic and bio-protective agents.

Extraction, purification and properties of water-soluble polysaccharides from mushroom Lepista nuda.

Lepista nuda has high nutritional and medicinal value, especially has high antioxidant, antitumor and antiviral activities. Based on results of single factor experiment, response surface methodology was used to optimize the extraction conditions of polysaccharides (LNP). Macroporous resin D301 was used to decolorization, and its technological conditions were determined by orthogonal experiment. In addition, two novel polysaccharides (LNP-1, LNP-2) were purified by DEAE Cellulose-52 and Sephadex G-150 chromatography. The molecular weight of LNP-1 is 11,703Da, mainly composed of mannose, glucose, galactose, xylose, arabinose and fucose, while the molecular weight of LNP-2 is 13,369Da, mainly composed of mannose, glucose, galactose, arabinose and fucose. The polysaccharide contents of crude LNP, LNP-1 and LNP-2 were 70.60%, 87.71% and 81.20% respectively, and the protein contents were 1.72%, 0.97% and 0.68% respectively. Their sulfuric contents were 3.39%, 5.02% and 8.64%, and uronic acid contents were 3.66%, 5.56% and 6.80%, respectively. Further studies showed that their ability to chelate iron ions, scavenge DPPH (1,1‑diphenyl‑2‑picrylhydrazyl) free radicals and scavenge superoxide anion radicals were 70.09%, 55.94% and 36.64% respectively. They showed strong ability to scavenge free radicals in a concentration-dependent manner. LNP is expected to be developed as a new efficacy factor in the food industry.

Characterization of polysaccharide fractions from fruit of Actinidia arguta and assessment of their antioxidant and antiglycated activities

A novel cell-wall polysaccharides (AAPs) were extracted from the fruits of Actinidia arguta and separated into four parts which were named water-eluted polysaccharide (WPS), salt-eluted polysaccharide (SPS)-1, SPS-2 and SPS-3. The monosaccharide composition and structural analysis showed that SPS-3 and SPS-2 were homogalacturonan (HG)-rich pectin, SPS-1 was rhamnogalacturonan (RG)-rich pectin and WPS was starch-like polysaccharides. All four kinds of polysaccharides displayed the ability to scavenge free radicals, chelate iron ion, inhibit lipid peroxidation and inhibit protein glycation, but SPS was obviously stronger than WPS. Especially SPS-3 displayed the strongest antioxidant and anti-glycated activities. In addition, the inhibitory effect of AAPs on AGEs formation is attributed to the inhibitory activity on the production of protein carbonyl group and the protective effects on the protein thiol group but not the scavenging capacity of dicarbonyl compounds, suggesting that its mechanisms of antiglycated effects may be of concern to their antioxidant activities.

Dual-target anti-Alzheimer’s disease agents with both iron ion chelating and monoamine oxidase-B inhibitory activity

MAO-B leads to an increase in the levels of hydrogen peroxide and oxidative free radicals, which contribute to the aetiology of the AD. Thus, both iron ion chelators and MAO-B inhibitors can be used to treat AD. Taking the coumarin derivatives and hydroxypyridinones as the lead compounds, a series of dual-target hybrids were designed and synthesised by Click Chemistry. The compounds were biologically evaluated for their iron ion chelating and MAO-B inhibitory activity. Most of the compounds displayed excellent iron ion chelating activity and moderate to good anti-MAO-B activity. Compounds 27b and 27j exhibited the most potent MAO-B inhibitory activity, with IC50 values of 0.68 and 0.86 μM, respectively. In summary, these dual-target compounds have the potential anti-AD activity.

Assessment of Antioxidant Capacity and Putative Healthy Effects of Natural Plant Products Using Soybean Lipoxygenase-Based Methods. An Overview.

In the last decades, increasing demand of antioxidant-rich foods and growing interest in their putative role in prevention of degenerative diseases have promoted development of methods for measuring Antioxidant Capacity (AC). Nevertheless, most of these assays use radicals and experimental conditions far from the physiological ones, and are able to estimate only one or a few antioxidant mechanisms. On the other hand, the novel LOX/RNO and LOX–FL methods, based on secondary reactions between the soybean lipoxygenase (LOX)-1 isoenzyme and either 4-nitroso-N,N-dimethylaniline (RNO) or fluorescein (FL), may provide a more comprehensive AC evaluation. In fact, they are able to detect simultaneously many antioxidant functions (scavenging of some physiological radical species, iron ion reducing and chelating activities, inhibition of the pro-oxidant apoenzyme) and to highlight synergism among phytochemicals. They are applied to dissect antioxidant properties of several natural plant products: food-grade antioxidants, cereal and pseudocereal grains, grain-derived products, fruits. Recently, LOX–FL has been used for ex vivo AC measurements of human blood samples after short- and long-term intakes of some of these foods, and the effectiveness in improving serum antioxidant status was evaluated using the novel Antioxidant/Oxidant Balance (AOB) parameter, calculated as an AC/Peroxide Level ratio. An overview of data is presented.

Uropathogenic enterobacteria use the yersiniabactin metallophore system to acquire nickel

Invasive Gram-negative bacteria often express multiple virulence-associated metal ion chelators to combat host-mediated metal deficiencies. Escherichia coli, Klebsiella, and Yersinia pestis isolates encoding the Yersinia high pathogenicity island (HPI) secrete yersiniabactin (Ybt), a metallophore originally shown to chelate iron ions during infection. However, our recent demonstration that Ybt also scavenges copper ions during infection led us to question whether it might be capable of retrieving other metals as well. Here, we find that uropathogenic E. coli also use Ybt to bind extracellular nickel ions. Using quantitative MS, we show that the canonical metal-Ybt import pathway internalizes the resulting Ni-Ybt complexes, extracts the nickel, and releases metal-free Ybt back to the extracellular space. We find that E. coli and Klebsiella direct the nickel liberated from this pathway to intracellular nickel enzymes. Thus, Ybt may provide access to nickel that is inaccessible to the conserved NikABCDE permease system. Nickel should be considered alongside iron and copper as a plausible substrate for Ybt-mediated metal import by enterobacteria during human infections.

Study on Kinetics of Anode Process of Chelated Iron Fuel Cell for Sulfur Recovery Unit of FLNG

Floating liquefied natural gas (FLNG) refers to water-based liquefied natural gas (LNG) operations employing technologies designed to enable the development of offshore natural gas resources. For environmental protection and safety, a sulfur recovery unit must be designed on the FLNG to purify hydrogen sulfide (H2S) contained in natural gas. The chelated-iron sulfur recovery process was a promising technique for the removal of H2S for waste minimization and resource recovery. In this process, an iron (Ⅲ) complex was used as an oxidant for dissolved H2S in the desulfurization catalysis into elemental sulfur. The catalyst was reduced to iron（Ⅱ）complex, and then underwent separation for removal of elemental sulfur. Using oxygen in the air as the oxidant, iron（Ⅱ）complex was oxidized to iron (Ⅲ) complex, thus realizing the recycling of the chelated-iron solution. However, in the traditional direct air regeneration process, the direct contact between air and chelated-iron catalyst can lead to degradation and subsequent failure of the chelated agent. Thus, the technology has encountered the problem of chelate degradation which made it difficult to ensure the reliable and economical operation. Furthermore, due to limitation of the FLNG space, the liquid chelated iron sulfur recovery process must also meet the requirements of a small footprint and light weight. A chelated-iron fuel-cell process was designed to achieve rapid regeneration of chelated iron. Since the fuel cell separated the direct chemical reaction between the chelated iron catalyst and air, it can effectively avoid the failure of chelated agent. Therefore, the fuel-cell-assisted chelated-iron process became a preferred solution for sulfur recovery for FLNG because it achieved fast regeneration of chelated iron catalyst, while producing electric energy. The electrochemical reactions were expressed as Anodic reaction: Fe 2+ L→Fe 3+ L+e - (1) Cathodic reaction: O 2+2H2O+4e -→ 4OH - (2) During the sulfur recovery reaction cycle, the oxidation rate of sulfur ions was very fast, and the overall reaction rate was limited by the regeneration rate of chelated iron ions. Therefore, by increasing the regeneration rate of the iron complex, the amount of catalyst can be effectively reduced, thereby minimizing the volume and weight of the sulfur recovery device of FLNG. In order to successfully complete the catalyst regeneration fuel cell design, it is necessary to study the kinetic mechanism of the anodic electrode reaction of different anodic materials in chelated iron catalysts fuel cell, so as to select the appropriate electrode materials. In this paper, cyclic voltammetry, polarization curves, and EIS measurements were used to study quantitatively the kinetic parameters of electrode processes for different electrode materials, including platinum, platinum plating titanium, graphite, ruthenium-titanium, and Harris alloy. Results showed that: (1) As the anode of the chelated iron catalyst fuel cell, reversible oxidation of ferrous ions as shown in reaction (1) occurs on the platinum, platinum-plated titanium, and graphite electrodes. The value of the electrode reaction rate constant K was almost the same on each of these electrodes, and the electrochemical reaction rate was fast. The rate-determining step was the diffusion of Fe2+. (2) When using ruthenium-titanium and Harris alloys as anode materials of the chelated iron catalyst fuel cell, many side reactions occurred on the electrode, and the reaction rate was smaller. However, when the suitable oxidation potential was applied, the reaction rate was increased while the occurrence of side reactions can be reduced. (3) The average current density of the platinum-plated titanium electrode used as the chelated-iron catalyst fuel cell anode was the largest of the six tested materials. Because the effective surface area was much larger than the apparent area, more reactive sites were available to carry out the electrode reactions. Therefore, the platinum-plated titanium electrode was the preferred anode material for chelated-iron catalyst fuel cells.

Improvements of Pd/Fe nanoparticles by ethylenediamine disuccinic acid for 2,4-D dechlorination

Abstract In the current study, the reaction system of ethylenediamine disuccinic acid (EDDS, a green and biodegradable chelating agent) improved nanoscale Pd/Fe was successfully established for effective dechlorination of 2,4-dichlorophenoxyacetic acid (2,4-D). The effects of different experimental parameters including EDDS dosage, initial pH, palladium ratio and reaction temperature on 2,4-D dechlorination were investigated. The results demonstrated that higher chelating agent dosage and palladium ratio, appropriate reaction temperature (20.0–35.0 °C) and a lower initial pH were beneficial for the efficient reductive dechlorination of 2,4-D. Over 99.5% of 2,4-D removal and 97.3% of phenoxyacetic acid (PA) generation were reached within just 50 min reaction time under these experimental conditions: 20.0 mmol L−1 EDDS concentration, 1.0 g L−1 nZVI content, initial pH 5.5, palladium loading 0.50%, reaction temperature 25.0 °C and stirring speed 200 r min−1. Characterization tests revealed that EDDS successfully removed the passivation layer on the nano-iron surface and thus exposed more surface active sites. In addition, EDDS chelated iron ions in the solution generated more soluble complex inhibiting the formation of inert layer on nanoscale Pd/Fe particles surface. As a result, the reactivity of nanoscale Pd/Fe was increased significantly. Findings from the present study suggested that the EDDS could be a promising substitute to enhance Pd/Fe reactivity and dechlorination efficiency.

Comparison of Purified Anthocyanin Isolated From In Vitro Cell Suspension Culture of Begonia malabarica, Begonia rex-cultorum ‘Baby Rainbow’ and its Antioxidant Activity

Anthocyanins are the most common flavonoid molecules of vegetables and fruits, especially berries. Human consumption of anthocyanins represents the highest among the flavonoids. Epidemiological studies have suggested that the consumption of anthocyanins lowers the risk of life style disorders like cardiovascular disease, diabetes, arthritis and cancer. Begonia malabarica Lam. of Begoniaceae, is used traditionally as anti-hypoglycemic, antimicrobial, wound healing and in the treatment of anemia. Begonia rex-cultorum ‘Baby rainbow’ an ornamental species was also substituted. Experimentation of in vitro cell suspension culture, isolation, purification of anthocyanin and its antioxidant potential are targeted in the present study. Explants such as leaves and nodes were cultured on MS medium with various phytohormones for callus induction. Leaf explants of Begonia cultured on MS medium fortified with 2, 4-D and BAP showed significant callus induction and also in terms of fresh and dry weights. Significant reddish coloured callus was achieved in cultures initiated from nodal explants in MS medium supplemented with 2, 4-D.Cell suspension cultures were also established in liquid MS medium. After 14 days of culture, cell suspension was obtained with optimal biomass accumulation. Subsequently, bioactive anthocyanin was isolated, purified and fractionated from B.malabarica andB. rex-cultorum‘Baby rainbow’ using amberlite column chromatography and LC-MS/MS analysis. The major anthocyanins eluted from Begonia speciesat 4.7-5.4 min. Tandem MS of the m/z 655.3 peak was identified as anthocyanidin Malvidin-3 –diglucoside as the major compound. The other peaks identified were (584.3) Malvidin or Peonidin, (459.2) Delphinidin + Glucose, (403.2) may be Cynanidin, (287.1) Cyanindin Aglycone and other m/z 242.3, 195.1 and 144.1 were sugar derivatives or fragments. Purified anthocyanin exhibited remarkable inhibition of linoleic acid oxidation and also a concentration dependent free-radical scavenging activities were noticed against DPPH•, hydroxyl radicals and superoxide anions. The degradation of deoxyribose by hydroxyl radicals was also inhibited via iron ion chelators, rather than by directly scavenging the radicals. The results are comparable with reducing power activity of ascorbate and catechin.

Design, synthesis, and evaluation of curcumin derivatives as Nrf2 activators and cytoprotectors against oxidative death

Activation of nuclear factor erythroid-2-related factor 2 (Nrf2) has been proven to be an effective means to prevent the development of cancer, and natural curcumin stands out as a potent Nrf2 activator and cancer chemopreventive agent. In this study, we synthesized a series of curcumin analogs by introducing the geminal dimethyl substituents on the active methylene group to find more potent Nrf2 activators and cytoprotectors against oxidative death. The geminally dimethylated and catechol-type curcumin analog (compound 3) was identified as a promising lead molecule in terms of its increased stability and cytoprotective activity against the tert-butyl hydroperoxide (t-BHP)-induced death of HepG2 cells. Mechanism studies indicate that its cytoprotective effects are mediated by activating the Nrf2 signaling pathway in the Michael acceptor- and catechol-dependent manners. Additionally, we verified by using copper and iron ion chelators that the two metal ion-mediated oxidations of compound 3 to its corresponding electrophilic o-quinone, contribute significantly to its Nrf2-dependent cytoprotection. This work provides an example of successfully designing natural curcumin-directed Nrf2 activators by a stability-increasing and proelectrophilic strategy.

Assessment of antioxidant activity in Victorian marine algal extracts using high performance thin-layer chromatography and multivariate analysis

The aim of this study was to develop and validate a rapid and simple high performance thin layer chromatographic (HPTLC) method to screen for antioxidant activity in algal samples. 16 algal species were collected from local Victorian beaches. Fucoxanthin, one of the most abundant marine carotenoids was quantified directly from the HPTLC plates before derivatization, while derivatization either with 2,2-diphenyl-1-picrylhydrazyl (DPPH) or ferric chloride (FeCl3) was used to analyze antioxidants in marine algae, based on their ability to scavenge non biological stable free radical (DPPH) or to chelate iron ions. Principal component analysis of obtained HPTLC fingerprints has classified algae species into 5 groups according to their chemical/antioxidant profiles. The investigated brown algae samples were found to be rich in non-and moderate-polar compounds and phenolic compounds with antioxidant activity. Most of the phenolic iron chelators also have shown free radical scavenging activity. Strong positive and significant correlations between total phenolic content and DPPH radical scavenging activity showed that, phenolic compounds, including flavonoids are the main contributors of antioxidant activity in these species. The results suggest that certain brown algae possess significantly higher antioxidant potential when compared to red or green algae and could be considered for future applications in medicine, dietary supplements, cosmetics or food industries. Cystophora monilifera extract was found to have the highest antioxidant concentration, followed by Zonaria angustata, Cystophora pectinate, Codium fragile, and Cystophora pectinata. Fucoxanthin was found mainly in the brown algae species. The proposed methods provide an edge in terms of screening for antioxidants and quantification of antioxidant constituents in complex mixtures. The current application also demonstrates flexibility and versatility of a standard HPTLC system in the drug discovery. Proposed methods could be used for the bioassay-guided isolation of unknown natural antioxidants and subsequent identification if combined with spectroscopic identification.

A theoretical study on the antioxidant properties of methoxy-substituted chalcone derivatives: A case study of kanakugiol and pedicellin through their Fe (II and III) coordination ability

A theoretical study on the antioxidant properties of two chalcone derivatives, kanakugiol and pedicellin, is performed by considering their Fe[Formula: see text] and Fe[Formula: see text] coordination ability. The objective of the study is to elucidate the factors influencing the stability of the isolated conformers, the nature of the complexes, metal[Formula: see text]ligand stability, metal ion affinities (MIA) and electronic properties of the cations before and after coordination to the ligand. The study is performed using the B3LYP/6–311[Formula: see text]G(2d,p)//B3LYP/6–31[Formula: see text]G(d,p) method. The LANL2DZ pseudopotential is selected to describe the Fe[Formula: see text] ions. Time-dependent density functional theory (TDDFT) method is used to assess the electronic UV–Vis spectra of the isolated chalcones and their complexes with Fe[Formula: see text] ions. The results suggest that the preferred complexes are those in which the Fe ion is coordinated at the hydroxyl-methoxy and hydroxyl-keto sites for kanakugiol and methoxy-keto site for pedicellin. Both kanakugiol and pedicellin have potential to chelate iron ions as demonstrated by their high MIA values in vacuo and in water solution. However, the ability of pedicellin to chelate iron is slightly lower than that of kanakugiol, indicating that the presence of the hydroxyl group has an effect of enhancing the metal binding abilities of the chalcone derivatives. In all the complexes obtained in vacuo, kanakugiol and pedicellin exhibit the ability to reduce the Fe[Formula: see text] ion. In water solution (which mimics the environment in biological systems or studies performed in vivo), Fe[Formula: see text] is reduced to Fe[Formula: see text] upon coordination to the ligand while the oxidation number of Fe[Formula: see text] upon coordination to the ligand remains virtually unchanged.