Quinone Reductase Activity Research Articles

Composição nutricional e atividades antioxidante e quimiopreventiva de câncer de frutos de Psidium myrtoides (O. Berg)

ABSTRACT: Psidiummyrtoides fruits food industries produce by-products such as liqueurs, ice cream, jellies, and juices. However, there needs to be more information about the nutritional composition of fruits, as well as the biological potential, mainly of seed flour.Therefore, the present study aimed to evaluate the nutritional composition and antioxidant and cancer chemopreventive activities of pulp and seed of fruits of Psidiummyrtoides. Moisture content, total minerals and mineral profile, total lipids and fatty acids profile, total proteins, dietary fiber (soluble and insoluble) and total carbohydrates were analyzed. Vitamins C and complex B, organic acids and the profile of phenolic compounds were also determined. DPPH and ABTS methods evaluated the antioxidant activity, and cancer chemopreventive activity was evaluated by quinone reductase induction and NF-κB inhibitory activity. The fruits are a good source of thiamine, iron, phosphorus, potassium, fiber, and protein. Linoleic acid was the major fatty acid in both pulp and seed. Quercetin (1600 µg/100g) and pyrogallol(819 µg/100g) were the major phenolic compounds pulp and seed, respectively. The fruits showed strong antioxidant capacity, mainly the seeds, and the ability to induce quinone reductase activity, highlighting a cancer chemopreventive activity. Seed flour has a high potential to enrich food, in addition to valuing agro-industrial by-products, where we can highlight 25%, 13% and 37% of the recommended daily intake for iron (1.6 mg/100g), phosphorus (58 mg/100g) and vitamin B1 (450 µg/100g), respectively, in addition to antioxidant and cancer chemopreventive activities.

Ameliorative Potential of Pumpkin Seed Oil (Cucurbita pepo L.) Against Tramadol-Induced Oxidative Stress.

The increase in the therapeutic use of tramadol in the management of moderate to severe pains in some disease conditions and its unregulated access has led to its associated toxicity and there is little or no information on the protection against its associated toxicity. Considering the medicinal value of pumpkin seed oil, its availability, and neglected use, it becomes necessary to evaluate the possible potential of the seed oil in tramadol-induced oxidative stress in Wister Albino rats. This study used fifty-six (56) albino rats to determine the impact of Cucurbita pepo seed oil (CPSO) on tramadol-induced oxidative stress. The rats were grouped into 7. After a week of acclimatization, rats in group 1 (normal control) had access to water and food, while rats in group 2 received 5mL/Kg (b.w) of normal saline. 100mg/kg of tramadol (TM) was delivered to groups 3-6 to induce toxicity. The third group (TM control) received no treatment, whilst the other 3 groups (TM-CPSO treatment groups) received 5, 2.5, and 1.5mL/Kg of CPSO, respectively. Group 7 received only 5mL/kg CPSO (CPSO group). Similarly, groups 2 through 7 had unrestricted access to food and water for 42days and received treatments via oral intubation once per day. Indicators of oxidative stress were discovered in the brain homogenate. TM toxicity was demonstrated by a considerable increase (P < .05) in the brain MDA level and a significant drop (P < .05) in the brain GSH level, as well as a significant reduction (P < .05) in GPx, catalase, SOD, GST, and quinone reductase activities. The dose-dependent delivery of CPSO was able to restore not only the activity but also the concentrations of the altered markers.

Expanding the Physiological Role of Aryl-Alcohol Flavooxidases as Quinone Reductases

Aryl-alcohol oxidases (AAOs) are members of the glucose-methanol-choline oxidase/dehydrogenase (GMC) superfamily. These extracellular flavoproteins have been described as auxiliary enzymes in the degradation of lignin by several white-rot basidiomycetes. In this context, they oxidize fungal secondary metabolites and lignin-derived compounds using O2 as an electron acceptor, and supply H2O2 to ligninolytic peroxidases. Their substrate specificity, including mechanistic aspects of the oxidation reaction, has been characterized in Pleurotus eryngii AAO, taken as a model enzyme of this GMC superfamily. AAOs show broad reducing-substrate specificity in agreement with their role in lignin degradation, being able to oxidize both nonphenolic and phenolic aryl alcohols (and hydrated aldehydes). In the present work, the AAOs from Pleurotus ostreatus and Bjerkandera adusta were heterologously expressed in Escherichia coli, and their physicochemical properties and oxidizing abilities were compared with those of the well-known recombinant AAO from P. eryngii. In addition, electron acceptors different from O2, such as p-benzoquinone and the artificial redox dye 2,6-Dichlorophenolindophenol, were also studied. Differences in reducing-substrate specificity were found between the AAO enzymes from B. adusta and the two Pleurotus species. Moreover, the three AAOs oxidized aryl alcohols concomitantly with the reduction of p-benzoquinone, with similar or even higher efficiencies than when using their preferred oxidizing-substrate, O2. IMPORTANCE In this work, quinone reductase activity is analyzed in three AAO flavooxidases, whose preferred oxidizing-substrate is O2. The results presented, including reactions in the presence of both oxidizing substrates-benzoquinone and molecular oxygen-suggest that such aryl-alcohol dehydrogenase activity, although less important than its oxidase activity in terms of maximal turnover, may have a physiological role during fungal decay of lignocellulose by the reduction of quinones (and phenoxy radicals) from lignin degradation, preventing repolymerization. Moreover, the resulting hydroquinones would participate in redox-cycling reactions for the production of hydroxyl free radical involved in the oxidative attack of the plant cell-wall. Hydroquinones can also act as mediators for laccases and peroxidases in lignin degradation in the form of semiquinone radicals, as well as activators of lytic polysaccharide monooxygenases in the attack of crystalline cellulose. Moreover, reduction of these, and other phenoxy radicals produced by laccases and peroxidases, promotes lignin degradation by limiting repolymerization reactions. These findings expand the role of AAO in lignin biodegradation.

Epoxinnamide: An Epoxy Cinnamoyl-Containing Nonribosomal Peptide from an Intertidal Mudflat-Derived Streptomyces sp.

Cinnamoyl-containing nonribosomal peptides (CCNPs) form a unique family of actinobacterial secondary metabolites and display various biological activities. A new CCNP named epoxinnamide (1) was discovered from intertidal mudflat-derived Streptomyces sp. OID44. The structure of 1 was determined by the analysis of one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) data along with a mass spectrum. The absolute configuration of 1 was assigned by the combination of advanced Marfey’s method, 3JHH and rotating-frame overhauser effect spectroscopy (ROESY) analysis, DP4 calculation, and genomic analysis. The putative biosynthetic pathway of epoxinnamide (1) was identified through the whole-genome sequencing of Streptomyces sp. OID44. In particular, the thioesterase domain in the nonribosomal peptide synthetase (NRPS) biosynthetic gene cluster was proposed as a bifunctional enzyme, which catalyzes both epimerization and macrocyclization. Epoxinnamide (1) induced quinone reductase (QR) activity in murine Hepa-1c1c7 cells by 1.6-fold at 5 μM. It also exhibited effective antiangiogenesis activity in human umbilical vein endothelial cells (IC50 = 13.4 μM).

Structural features determining the vitamin K epoxide reduction activity in the VKOR family of membrane oxidoreductases.

Vitamin K epoxide reductases (VKORs) are a large family of integral membrane enzymes found from bacteria to humans. Human VKOR, specific target of warfarin, has both the epoxide and quinone reductase activity to maintain the vitamin K cycle. Bacterial VKOR homologs, however, are insensitive to warfarin inhibition and are quinone reductases incapable of epoxide reduction. What affords the epoxide reductase activity in human VKOR remains unknown. Here, we show that a representative bacterial VKOR homolog can be converted to an epoxide reductase that is also inhibitable by warfarin. To generate this new activity, we first substituted several regions surrounding the active site of bacterial VKOR by those from human VKOR based on comparison of their crystal structures. Subsequent systematic substitutions narrowed down to merely eight residues, with the addition of a membrane anchor domain, that are responsible for the epoxide reductase activity. Substitutions corresponding to N80 and Y139 in human VKOR provide strong hydrogen bonding interactions to facilitate the epoxide reduction. The rest of six substitutions increase the size and change the shape of the substrate-binding pocket, and the membrane anchor domain stabilizes this pocket while allowing certain flexibility for optimal binding of the epoxide substrate. Overall, our study reveals the structural features of the epoxide reductase activity carried out by a subset of VKOR family in the membrane environment.

Chemical Constituents from the Rhizome of Ligusticum chuanxiong Hort. and Their Nrf2 Inducing Activity.

The rhizome of Ligusticum chuanxiong Hort. has been widely used for the therapy of diabetic nephropathy (DN) in traditional Chinese medicine (TCM). The nuclear transcription factor erythroid 2-related factor (Nrf2) is a potential target for treating DN. The purpose of this research was to study the chemical constituents from the rhizome of L. chuanxiong, evaluate their Nrf2 inducing activity, and find the molecules with potential therapeutic effect against DN. In this study, two new phthalides (1-2) along with twenty-seven known constituents were obtained from the rhizome of L. chuanxiong. Their structures were elucidated through various spectroscopic methods. Twelve constituents, including eight phthalides (2, 5, 6,10-13, 14) and four other compounds (17, 18, 20,28), stimulated NAD(P)H: quinone reductase (QR) activity, suggesting that these bioactive constituents were potential Nrf2 activators. Among the isolated compounds, phthalide levistolide A (LA, 14) upregulated the protein levels of Nrf2, NQO1, and γ-GCS in a dose-dependent manner. Our results implied that the clinical application of the rhizome of L. chuanxiong as an anti-DN drug in TCM might be attributed to the Nrf2 inducing effect of phthalides. Thus, phthalides is a group of promising leading molecules for discovering anti-DN agents.

Reversal of Insulin Resistance in Overweight and Obese Subjects by trans-Resveratrol and Hesperetin Combination-Link to Dysglycemia, Blood Pressure, Dyslipidemia, and Low-Grade Inflammation.

The dietary supplement, trans-resveratrol and hesperetin combination (tRES-HESP), induces expression of glyoxalase 1, countering the accumulation of reactive dicarbonyl glycating agent, methylglyoxal (MG), in overweight and obese subjects. tRES-HESP produced reversal of insulin resistance, improving dysglycemia and low-grade inflammation in a randomized, double-blind, placebo-controlled crossover study. Herein, we report further analysis of study variables. MG metabolism-related variables correlated with BMI, dysglycemia, vascular inflammation, blood pressure, and dyslipidemia. With tRES-HESP treatment, plasma MG correlated negatively with endothelial independent arterial dilatation (r = −0.48, p < 0.05) and negatively with peripheral blood mononuclear cell (PBMC) quinone reductase activity (r = −0.68, p < 0.05)—a marker of the activation status of transcription factor Nrf2. For change from baseline of PBMC gene expression with tRES-HESP treatment, Glo1 expression correlated negatively with change in the oral glucose tolerance test area-under-the-curve plasma glucose (ΔAUGg) (r = −0.56, p < 0.05) and thioredoxin interacting protein (TXNIP) correlated positively with ΔAUGg (r = 0.59, p < 0.05). Tumor necrosis factor-α (TNFα) correlated positively with change in fasting plasma glucose (r = 0.70, p < 0.001) and negatively with change in insulin sensitivity (r = −0.68, p < 0.01). These correlations were not present with placebo. tRES-HESP decreased low-grade inflammation, characterized by decreased expression of CCL2, COX-2, IL-8, and RAGE. Changes in CCL2, IL-8, and RAGE were intercorrelated and all correlated positively with changes in MLXIP, MAFF, MAFG, NCF1, and FTH1, and negatively with changes in HMOX1 and TKT; changes in IL-8 also correlated positively with change in COX-2. Total urinary excretion of tRES and HESP metabolites were strongly correlated. These findings suggest tRES-HESP counters MG accumulation and protein glycation, decreasing activation of the unfolded protein response and expression of TXNIP and TNFα, producing reversal of insulin resistance. tRES-HESP is suitable for further evaluation for treatment of insulin resistance and related disorders.

Role of quinone reductases in extracellular redox cycling in lichenized ascomycetes

Our previous work showed that many lichenized Ascomycetes can generate hydroxyl radicals using quinone-based extracellular redox cycling. During cycling, hydroquinones must be formed and subsequently regenerated from quinones using a quinone reductase (QR). However, we also showed that no simple correlation exists between QR activity and rates of hydroxyl radical formation. To further investigate the role of QR in hydroxyl radical formation, three model lichen species, Leptogium furfuraceum, Lasallia pustulata and Peltigera membranacea were selected for further investigation. All possessed QR activity and could metabolize quinones, and both Leptogium furfuraceum and Lasallia pustulata actively produced hydroxyl radicals. By contrast, P. membranacea produced almost no hydroxyl radicals, and although the lichen readily metabolized quinones, no hydroquinone production was detected. Peltigera had laccase (LAC) activity that was c. 50 times higher than in the other two species, suggesting that LAC rapidly oxidizes the hydroquinones, preventing radical formation deriving from auto-oxidation. It appears that in some lichens hydroxyl radical formation is blocked by the presence of high redox enzyme activity. QR from P. didactyla was studied further and found to display similar properties to the enzyme from free-living fungi, although it possessed an unusually high molecular mass (c. 62 kDa).

338-OR: Reversal of Insulin Resistance by Resveratrol and Hesperetin Combination in Overweight and Obese Subjects Correlates with Decrease in Expression of Thioredoxin Interacting Protein

Trans-Resveratrol and hesperetin combination (tRES-HESP) in randomized, double-blind, placebo-controlled crossover study in overweight and obese subjects corrected insulin resistance; healthy aging through functional food study (HATFF, Clinicaltrials.gov identifier NCT02095873). tRES-HESP is an optimized supplement for induction of expression of glyoxalase 1 (Glo1) via activation of transcription factor Nrf2. Increased Glo1 expression decreases reactive metabolite, methylglyoxal (MG), contributing to insulin resistance through glycation-linked unfolded protein formation and activation of the unfolded protein response (UPR). Herein, we report further analysis of study variables and follow-up reverse translational studies. With tRES-HESP treatment, plasma MG correlated negatively with peripheral blood mononuclear cell (PBMC) quinone reductase activity - a marker of Nrf2 activation (r = - 0.68, P&amp;lt;0.01). For change from baseline of PBMC gene expression with tRES-HESP treatment (assessed by the Nanostring method), change in area-under-the-curve plasma glucose (ΔAUGg) during oral glucose tolerance tests correlated negatively with change in Glo1 expression (r = - 0.56, P&amp;lt;0.05) and correlated positively with change in expression of thioredoxin interacting protein (TXNIP) (r = 0.59, P&amp;lt;0.05). In reverse translational studies, we found tRES-HESP decreased TXNIP expression by 39 ± 1% (P&amp;lt;0.001) in human hepatocyte-like HepG2 cells and 14 ± 3% in BJ fibroblasts in vitro (P&amp;lt;0.01). tRES-HESP may decrease TXNIP expression by decreasing the MG-driven UPR and by direct Nrf2-driven down regulation. TXNIP is a mediator of insulin resistance in liver and skeletal muscle and impaired pancreatic beta-cell insulin secretion. tRES-HESP is suitable for further evaluation for prevention and treatment of type 2 diabetes where decreased TXNIP may contribute to the therapeutic response. Disclosure M. Xue: None. M. Weickert: None. N. Rabbani: None. P. Thornalley: None. Funding Qatar Foundation; Qatar University

Quinone reductase activity is widespread in lichens

AbstractIn our earlier work, we demonstrated that the oxidases tyrosinase (TYR), laccase (LAC), and a heme peroxidase (POX) occur widely in lichens. Here we report on the occurrence of another oxidoreductase enzyme, quinone reductase (QR) (EC 1.6.5.5). While QR has been reported to occur widely in other organisms, there is currently no information on QR activities in lichens. Here we present a survey of QR activity in 14 species of lichens. Results demonstrate that QR activity is readily detectable in all lichen species tested. However, activities vary greatly, with ‘jelly’ lichens in the genera Collema and Leptogium having the highest activities. QR, LAC and POX are all believed to have a role in extracellular hydroxyl radical production. However, in this study no correlation was found between the activities of these enzymes and the rates at which hydroxyl radicals were produced. Possible roles for QR in lichen biology are discussed.

Svalbamides A and B, Pyrrolidinone-Bearing Lipodipeptides from Arctic Paenibacillus sp.

Two new secondary metabolites, svalbamides A (1) and B (2), were isolated from a culture extract of Paenibacillus sp. SVB7 that was isolated from surface sediment from a core (HH17-1085) taken in the Svalbard archipelago in the Arctic Ocean. The combinational analysis of HR-MS and NMR spectroscopic data revealed the structures of 1 and 2 as being lipopeptides bearing 3-amino-2-pyrrolidinone, d-valine, and 3-hydroxy-8-methyldecanoic acid. The absolute configurations of the amino acid residues in svalbamides A and B were determined using the advanced Marfey’s method, in which the hydrolysates of 1 and 2 were derivatized with l- and d- forms of 1-fluoro-2,4-dinitrophenyl-5-alanine amide (FDAA). The absolute configurations of 1 and 2 were completely assigned by deducing the stereochemistry of 3-hydroxy-8-methyldecanoic acid based on DP4 calculations. Svalbamides A and B induced quinone reductase activity in Hepa1c1c7 murine hepatoma cells, indicating that they represent chemotypes with a potential for functioning as chemopreventive agents.

Nitroreductase Activites in Giardia lamblia: ORF 17150 Encodes a Quinone Reductase with Nitroreductase Activity.

The intestinal diplomonadid Giardia lamblia is a causative agent of persistent diarrhea. Current treatments are based on nitro drugs, especially metronidazole. Nitro compounds are activated by reduction, yielding toxic intermediates. The enzymatic systems responsible for this activation are not completely understood. By fractionating cell free crude extracts by size exclusion chromatography followed by mass spectrometry, enzymes with nitroreductase (NR) activities are identified. The protein encoded by ORF 17150 found in two pools with NR activities is overexpressed and characterized. In pools of fractions with main NR activities, previously-known NRs are identified, as well as a previously uncharacterized protein encoded by ORF 17150. Recombinant protein 17150 is a flavoprotein with NADPH-dependent quinone reductase and NR activities. Besides a set of previously identified NRs, we have identified a novel enzyme with NR activity.

Effect of resveratrol, carnitin, quercetin and aromatic amino acids on the xenobiotic metabolising and antioxidant enzymes in the liver during obesity in rats with different genotypes

The use of minor biologically active substances (BAS) in specialized products is one of the promising areas in the diet therapy for obesity and other alimentary-dependent diseases (metabolic syndrome, type 2 diabetes mellitus, etc.). The effects of the BAS in patients are often ambiguous, depending on a number of factors, one of which is the state of the organism enzyme systems (enzymes of xenobiotic metabolism and antioxidant defense), the patient's genotype, and many others. The aim was to study the effect of BAS [quercetin (Q), L-carnitine (L-Car), resveratrol (Res), aromatic amino acids tyrosine (Tyr) and tryptophan (Trp)] on the activities of phase I and II of xenobiotic-metabolising enzymes and antioxidant enzymes in rats using various in vivo models of obesity and with impaired dopamine transport. Material and methods. The activities of cytochrome P450 enzymes (CYP1A1 and CYP3A), glutathione transferase (GT), UDPglucuronosyltransferase (UDP-GT), hemoxygenase-1 (HO-1), and quinone reductase (QR) were determined by fluorimetric, spectrophotometric methods and HPLC in microsomes and cytosolic fraction of rat's liver. We used rats of outbred Wistar line, Zucker ZF line with hereditarily determined obesity and DAT-KO line with a knockout of the DAT dopamine transporter gene, which for 62 days were fed a standard balanced control or high-carbohydrate high-fat diet (30% fat by weight and 20% fructose solution instead of water) supplemented with BAS, such as Q, Res, L-Car, Tyr and Trp in doses 50, 25, 300, 1250 and 250 mg/kg of body weight respectively. Results and discussion. The presence of a DAT knockout led to a small but statistically significant decrease in the activity of GT in the liver in both homozygous and heterozygous animals. The CYP1A1 activity was significantly decreased in all carriers of the DAT knockout gene, while HO-1 activity, on the contrary, was increased, independently of the composition of the diet used. In Zucker ZF rats of all groups, in comparison with Wistar rats fed the corresponding diets, the activities of GT, UDP-GT, CYP1A1, CYP3A and QR were significantly reduced in terms of the total protein content. HO-1 activity was reduced in Zucker ZF rats in comparison with Wistar rats to a lesser extent, however, the addition of Q significantly influenced the difference between the two lines. Trp consumption led to a significant increase in GT activity in Wistar rats. In DAT-KO homozygotes this effect was insignificant, while in heterozygotes it was absent. Similarly, consumption of Trp resulted in a significant increase in CYP1A1 activity only in Wistar rats, but not in DAT-KO rats. The activity of UDP-GT under Trp intake increased only in DAT heterozygotes. The genotype significantly influenced the response of QR activity to Trp consumption, but in an ambiguous way - there was an increase in activity in heterozygotes and a decrease in homozygotes for DAT knockout. CYP1A1 activity was significantly increased in rats treated with Tyr. Conclusion. The data obtained indicate that the effect of various dietary supplements used in the treatment of obesity and metabolic syndrome on the xenobiotic-metabolising enzymes and antioxidant enzymes can have a different nature and direction depending on the genotype and the level of spontaneous physical activity and energy expenditure determined by it, which should be taken into account when approaches to personalized diet therapy of alimentary-dependent diseases are developing.

An Assay to Determine NAD(P)H: Quinone Oxidoreductase Activity in Cell Extracts from Candida glabrata.

Flavodoxin-like proteins (Fld-LPs) are an important constituent of the oxidative stress defense system in several organisms and highly conserved from bacteria to humans. These proteins possess NAD(P)H:quinone oxidoreductase activity and convert quinones to hydroquinones through two-electron reduction, using NAD(P)H and quinone as electron donor and acceptor, respectively. Purified yeast and bacterial Fld-LPs exhibit NAD(P)H:quinone oxidoreductase activity in vitro. Here, we describe a protocol to measure oxidoreductase activity of Fld-LPs that are present in extracts of whole cells. We have recently shown that the assembly and activity of a Fld-LP, CgPst2, is regulated by an aspartyl protease-mediated cleavage of its C-terminus in the pathogenic yeast Candida glabrata. Mutant yeast where the CgPST2 gene was deleted lacked cellular NAD(P)H:quinone oxidoreductase activity and displayed elevated susceptibility to menadione stress. The protocol described herein is based on the measurement of NADH oxidation (conversion of NADH to NAD+) by endogenous Fld-LPs in the presence of quinone menadione. This assay can be performed with whole cell lysates prepared by the mechanical lysis of C. glabrata cells and does not require expression and purification of Fld-LPs from a heterogeneous system, thereby allowing researchers to study the effect of different posttranslational modifications and varied structural states of Fld-LPs on their enzymatic activities. Since many FLP-LPs are known to exist in dimeric and tetrameric states possessing differential activities, our efficient and easy-to-use assay can reliably detect and validate their quinone reductase activities. Although we have used menadione with CgPst2 enzyme in our study, the protocol can easily be modified to examine the presence of Fld-LPs with specificity for other quinones. As this assay does not require many expensive chemicals, it can readily be scaled up and adapted for other medically important fungi and potentially be a useful tool to characterize fungal oxidative stress response systems and screen inhibitors specific for fungal Fld-LPs, thereby contributing to our understanding of fungal pathogenesis mechanisms.

YMR152W from Saccharomyces cerevisiae encoding a novel aldehyde reductase for detoxification of aldehydes derived from lignocellulosic biomass

Aldehydes are the main inhibitors generated during the pretreatment of lignocellulosic biomass, which can inhibit cell growth and disturb subsequent fermentation. Saccharomyces cerevisiae has the intrinsic ability to in situ detoxify aldehydes to their less toxic or nontoxic alcohols by numerous aldehyde dehydrogenases/reductases during the lag phase. Herein, we report that an uncharacterized open reading frame YMR152W from S.cerevisiae encodes a novel aldehyde reductase with catalytic functions for reduction of at least six aldehydes, including two furan aldehydes (furfural and 5-hydroxymethylfurfural), three aliphatic aldehydes (acetaldehyde, glycolaldehyde, and 3-methylbutanal), and an aromatic aldehyde (benzaldehyde) with NADH or NADPH as the co-factor. Particularly, Ymr152wp displayed the highest specific activity (190.86 U/mg), and the best catalytic rate constant (Kcat), catalytic efficiency (Kcat/Km), and affinity (Km) when acetaldehyde was used as the substrate with NADH as the co-factor. The optimum pH of Ymr152wp is acidic (pH 5.0-6.0), but this enzyme is more stable in alkaline conditions (pH 8.0). Metal ions, chemical protective additives, salts, and substrates could stimulate or inhibit enzyme activities of Ymr152wp in varying degrees. Ymr152wp was classified into the quinone oxidoreductase (QOR) subfamily of the medium-chain dehydrogenase/reductase (MDR) family based on the results of amino acid sequence analysis and phylogenetic analysis. Although Ymr152wp was grouped into the QOR family, no quinone reductase activity was observed using typical quinones (9,10-phenanthrenequinone, 1,2-naphthoquinone, and p-benzoquinone) as the substrates. This study provides guidelines for exploring more uncharacterized aldehyde reductases in S.cerevisiae for in situ detoxification of aldehyde inhibitors derived from lignocellulosic hydrolysis.

Formicolides A and B, Antioxidative and Antiangiogenic 20-Membered Macrolides from a Wood Ant Gut Bacterium.

Two new macrolides, formicolides A (1) and B (2), were isolated from Streptomyces sp. BA01, a gut bacterial strain of the wood ant (Formica yessensis). Their 20-membered macrocyclic lactone structures were established using NMR and mass spectrometric data. The relative configurations of the formicolides were determined by J-based configuration analysis utilizing ROESY, HETLOC, and HECADE NMR spectroscopic data. Genomic and bioinformatics analysis of the bacterial strain enabled us to identify the type-I polyketide synthase pathway employing a trans-acyltransferase system. The absolute configurations of 1 and 2 are proposed based on detailed analysis of the sequences of the ketoreductases in the modular gene cluster and statistical comparative analysis of the experimental NMR chemical shifts and quantum mechanical calculations. Formicolides A and B (1 and 2) induced quinone reductase activity in murine Hepa-1c1c7 cells and antiangiogenic activity by suppression of tube formation in human umbilical vein endothelial cells.

Effect of Isothiocyanates on the Activity of &lt;i&gt;Lactobacillus plantarum&lt;/i&gt; Exposed to Irradiation

Two isothiocyanates, i.e., sulforaphane (SFA) and sulforaphene (SFE), are suggested to be used as an alternative chemopreventive diet. This study was focused on the effect of SFA and SFE on Lactobacillus plantarum, which has been subjected to the irradiation (2-50 Gy). The cultures grown in De Man, Rogosa and Sharpe (MRS) and Tryptone Soya Broth (TSB) were compared in terms of bacteria physiological activity under tested conditions. Broth composition notably influenced the bacteria growth kinetic parameters, as well as culture response to the oxidative stress. Activity of L. plantarum cells after irradiation was evaluated by their dehydrogenase (DHA) and quinone-reductase (QR) activities. The enzyme activity was quantified in living cells. Bacterial cultures obtained in MRS and TSB broth, demonstrated contrasting characteristics in their enzyme activities. The MRS-grown culture did not show any QR activity, whereas the TSB-grown cells showed a non-linear response towards gamma-irradiation with a maximum inhibition being at 10 Gy. Addition of SFA or SFE in concentration of 1 µg/mL to the cultures before irradiation exposure recovered the QR activity from 23% in a non-amended variant up to 102% and 121%, respectively, taking the non-irradiated non-amended variant as 100%.

Chemopreventive Properties of Extracts Obtained from Blueberry (Vaccinium myrtillus L.) and Jabuticaba (Myrciaria cauliflora Berg.) in Combination with Probiotics

The association of probiotics and fruit extracts may influence the chemopreventive effect of colorectal cancer. In this context, antiproliferative activity was evaluated to select the best extracts that would be added probiotics, after addition of Bifidobacterium or Lactobacillus in the extracts the antiradical and antioxidant activity, quinone reductase (QR) assay and apoptosis assay were evaluated. Four extracts were isolated: E1: rich in total phenolic compounds; E2: rich in water-soluble phenolic compounds; E3: rich in most apolar phenolic compounds and E4: rich in anthocyanins. The antiproliferative results showed that the best extracts for blueberry and jabuticaba were, respectively the extract E4 and E2. After addition of the probiotic bacteria in these best extracts, it was observed that E2 from jabuticaba presented significantly higher antiradical and antioxidant activity values compared to E4 from blueberry before and after addition of probiotics. There was also a 9-fold increase in activity of QR by the E2 from jabuticaba with Lactobacillus (JL). Likewise, this same extract showed a significant increase both in apoptotic and necrotic cells for both cells. In conclusion, extract rich in water-soluble phenolic compounds (E2) from jabuticaba presented a greater chemopreventive effect compared to the others.

A novel Xanthomonas citri subsp. citri NADPH quinone reductase involved in salt stress response and virulence

BackgroundXanthomonas citri subsp. citri (Xcc), the causal agent of citrus canker is maintained as an epiphyte on citrus leaves until entering the plant tissue. During epiphytic survival, bacteria may encounter low water availability that challenges the infection process. Proteomics analyses of Xcc under saline stress, mimicking the conditions found during epiphytic survival, showed increased abundance of a putative NAD(P)H dehydrogenase encoded by XAC2229. MethodsExpression levels of XAC2229 and a Xcc mutant in XAC2229 were analyzed in salt and oxidative stress and during plant-pathogen interaction. An Escherichia coli expressing XAC2229 was obtained, and the role of this protein in oxidative stress resistance and in reactive oxygen species production was studied. Finally, Xac2229 protein was purified, spectrophotometric and cofactor analyses were done and enzymatic activities determined. ResultsXAC2229 was expressed under salt stress and during plant-pathogen interaction. ΔXAC2229 mutant showed less number of cankers and impaired epiphytic survival than the wild type strain. ΔXAC2229 survived less in the presence of H2O2 and produced more reactive oxygen species and thiobarbituric acid-reactive substances than the wild type strain. Similar results were observed for E. coli expressing XAC2229. Xac2229 is a FAD containing flavoprotein, displays diaphorase activity with an optimum at pH 6.0 and has quinone reductase activity using NADPH as an electron donor. ConclusionsA FAD containing flavoprotein from Xcc is a new NADPH quinone reductase required for bacterial virulence, particularly in Xcc epiphytic survival on citrus leaves. General significanceA novel protein involved in the worldwide disease citrus canker was characterized.

Beta-ionone-inhibited proliferation of breast cancer cells by inhibited COX-2 activity.

As one of the isoprenoids and widely derived from many fruits and vegetables, β-ionone (BI) has a potent inhibitory proliferation of cancer cells in vitro and in vivo. However, its exact mechanism is still uncompleted understood and needs to be further verified. Cyclooxygenase-2 (COX-2), as a potential target of cancer chemoprevention, has been played pivotal roles in proliferation of tumor cells and carcinogenesis. Thus, the objective of present study was to determine that BI inhibited the activity of COX-2 in breast cancer and related to cancer cell models. Cell proliferation, DNA synthesis, the distribution of cell cycle, apoptosis induction and the expression of P38-MAPK protein were determined in MCF-7 cells by methylene blue, 3H-thymidine (TdR) incorporation, flow cytometry, TUNEL and Western blotting assays. Quinone reductase (QR) activity was determined in murine hepatoma Hepa1c1c7 cells by enzyme-linked immunosorbent assay (ELISA). The expression of COX-2 in a phorbol-12-myristate-13-acetate (PMA)-induced cell model and mammary tumor tissues was examined by Western blotting and immunohistochemistry. The results showed that BI significantly inhibited cell proliferation and DNA synthesis, arrested the distribution of cell cycle at the S phase or decreased proteins related to cell cycle such as cyclin D1 and CDK4, induced apoptosis and increased the expression of p-P38 in MCF-7 cells. BI at low doses (< 50μmol/L) significantly increased QR activity, decreased the expression of COX-2 protein and prostaglandin E2 (PEG2) release in cell models. In addition, BI also significantly decreased the expression of COX-2 protein in rat mammary tumor tissues. Therefore, our findings indicate that BI possesses inhibitory proliferation of breast cancer cells through down-regulation of COX-2 activity.