Antioxidant, Antidiabetic, Anticholinergic, and Antiglaucoma Effects of Magnofluorine

Magnofluorine, a secondary metabolite commonly found in various plants, has pharmacological potential; however, its antioxidant and enzyme inhibition effects have not been investigated. We investigated the antioxidant potential of Magnofluorine using bioanalytical assays with 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS^•+), N,N-dimethyl-p-phenylenediamine dihydrochloride (DMPD^•+), and 1,1-diphenyl-2-picrylhydrazyl (DPPH^•) scavenging abilities and K₃[Fe(CN)₆] and Cu²⁺ reduction abilities. Further, we compared the effects of Magnofluorine and butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), α-Tocopherol, and Trolox as positive antioxidant controls. According to the analysis results, Magnofluorine removed 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals with an IC₅₀ value of 10.58 μg/mL. The IC₅₀ values of BHA, BHT, Trolox, and α-Tocopherol were 10.10 μg/mL, 25.95 μg/mL, 7.059 μg/mL, and 11.31 μg/mL, respectively. Our results indicated that the DPPH· scavenging effect of Magnofluorine was similar to that of BHA, close to that of Trolox, and better than that of BHT and α-tocopherol. The inhibition effect of Magnofluorine was examined against enzymes, such as acetylcholinesterase (AChE), α-glycosidase, butyrylcholinesterase (BChE), and human carbonic anhydrase II (hCA II), which are linked to global disorders, such as diabetes, Alzheimer’s disease (AD), and glaucoma. Magnofluorine inhibited these metabolic enzymes with Ki values of 10.251.94, 5.991.79, 25.411.10, and 30.563.36 nM, respectively. Thus, Magnofluorine, which has been proven to be an antioxidant, antidiabetic, and anticholinergic in our study, can treat glaucoma. In addition, molecular docking was performed to understand the interactions between Magnofluorine and target enzymes BChE (D: 6T9P), hCA II (A:3HS4), AChE (B:4EY7), and α-glycosidase (C:5NN8). The results suggest that Magnofluorine may be an important compound in the transition from natural sources to industrial applications, especially new drugs.

Screening of Carbonic Anhydrase, Acetylcholinesterase, Butyrylcholinesterase, and α-Glycosidase Enzyme Inhibition Effects and Antioxidant Activity of Coumestrol

Coumestrol (3,9-dihydroxy-6-benzofuran [3,2-c] chromenone) as a phytoestrogen and polyphenolic compound is a member of the Coumestans family and is quite common in plants. In this study, antiglaucoma, antidiabetic, anticholinergic, and antioxidant effects of Coumestrol were evaluated and compared with standards. To determine the antioxidant activity of coumestrol, several methods—namely N,N-dimethyl-p-phenylenediamine dihydrochloride radical (DMPD^•+)-scavenging activity, 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonate) radical (ABTS^•+)-scavenging activity, 1,1-diphenyl-2-picrylhydrazyl radical (DPPH^•)-scavenging activity, potassium ferric cyanide reduction ability, and cupric ion (Cu²⁺)-reducing activity—were performed. Butylated hydroxyanisole (BHA), Trolox, α-Tocopherol, and butylated hydroxytoluene (BHT) were used as the reference antioxidants for comparison. Coumestrol scavenged the DPPH radical with an IC₅₀ value of 25.95 μg/mL (r²: 0.9005) while BHA, BHT, Trolox, and α-Tocopherol demonstrated IC₅₀ values of 10.10, 25.95, 7.059, and 11.31 μg/mL, respectively. When these results evaluated, Coumestrol had similar DPPH^•-scavenging effect to BHT and lower better than Trolox, BHA and α-tocopherol. In addition, the inhibition effects of Coumestrol were tested against the metabolic enzymes acetylcholinesterase (AChE), butyrylcholinesterase (BChE), carbonic anhydrase II (CA II), and α-glycosidase, which are associated with some global diseases such as Alzheimer’s disease (AD), glaucoma, and diabetes. Coumestrol exhibited K_i values of 10.25 ± 1.94, 5.99 ± 1.79, 25.41 ± 1.10, and 30.56 ± 3.36 nM towards these enzymes, respectively.

Effect of Butylated Hydroxy Toluene and Vitamin E on the Cryosurvivability of Buck Semen

BACKGROUND

The quality of frozen semen can be improved by supplementing Tris extender with antioxidant to prevent oxidation and maintain sperm motility.

OBJECTIVE

To study the effects of adding combinations of suitable concentrations of butylated hydroxy toluene (BHT) and Vitamin E in Tris extender on the quality of frozen goat semen.

MATERIALS AND METHODS

A total of 40 ejaculates collected from five Beetal bucks were used to study the effect on the quality of frozen semen of supplementing Tris extender with 200 µM BHT, 2 mM Vitamin E and 200 µM BHT + 2 mM Vitamin E.

RESULTS

The sperm motility, live sperm, live intact acrosome and HOST-reacted sperm differed significantly (P<0.01) between stages and between antioxidants. There was no significant difference (P<0.05) in interaction between stages (equilibration, freezing) and antioxidants, except for HOST-reacted sperm. Critical difference test revealed that Tris extender containing 2 mM vitamin E showed significantly (P<0.05) higher sperm motility, live sperm, live intact acrosome and HOST-reacted sperm, and significantly (P<0.05) lower release of alanine transaminase (ALT) and aspartate transaminase (AST).

CONCLUSION

Supplementation of Tris extender with 2 mM vitamin E maintained superior quality of frozen Beetal buck semen.

Polydatin-fatty acid conjugates are effective antioxidants for stabilizing omega 3-containing bulk fish oil and fish oil emulsions

Candida antarctica lipase B-catalysed synthesis of lipophilic esters of polydatin was investigated along with their antioxidant activities. The effects of synthesis parameters such as solvent, substrate molar ratio, enzyme concentration, addition of molecular sieves, reaction temperature and time on the production of ester were studied and optimised. The highest production of esters was obtained with acetone as the reaction solvent. The antioxidant activities of the esters were compared with those of commercial butylated hydroxytoluene (BHT) and α-tocopherol. All polydatin esters inhibited the oxidative destruction of β-carotene more effectively than did BHT and α-tocopherol. Results of thiobarbituric acid tests showed that in bulk fish oil, all esters were more effective than α-tocopherol at 2 mmol/kg concentration but were not as effective as BHT. In fish oil-emulsions, all esters were more effective than both BHT and α-tocopherol at 2 mmol/kg concentration. The synthesized polydatin esters are promising antioxidants for oil/fat-based foods.

Full Structural Characterization of Homoleptic Complexes of Diacetylcurcumin with Mg, Zn, Cu, and Mn: Cisplatin-level Cytotoxicity in Vitro with Minimal Acute Toxicity in Vivo

At the present time, scientists place a great deal of effort worldwide trying to improve the therapeutic potential of metal complexes of curcumin and curcuminoids. Herein, the synthesis of four homoleptic metal complexes with diacetylcurcumin (DAC), using a ligand designed to prevent the interaction of phenolic groups, rendering metal complexes through the β-diketone functionality, is reported. Due to their physiological relevance, we used bivalent magnesium, zinc, copper, and manganese for complexation with DAC. The resulting products were characterized by ultraviolet-visible (UV-Vis), fluorescence spectroscopy, infrared spectroscopy (IR), liquid and solid-state nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR), magnetic moment, mass spectrometry (MS), single crystal, and powder X-ray diffraction (SCXRD and PXRD). Crystallization was achieved in dimethylsulfoxide (DMSO) or N,N-dimethylformamide (DMF) as triclinic systems with space group P-1, showing the metal bound to the β-diketone function, while the 1H-NMR confirmed the preference of the enolic form of the ligand. Single crystal data demonstrated a 1:2 metal:ligand ratio. The inhibition of lipid peroxidation was evaluated using the thiobarbituric acid reactive substance assay (TBARS). All four metal complexes (Mg, Zn, Cu, and Mn) exhibited good antioxidant effect (IC50 = 2.03 ± 0.27, 1.58 ± 0.07, 1.58 ± 0.15 and 1.24 ± 0.10 μM respectively) compared with butylated hydroxytoluene (BHT) and α-tocopherol. The cytotoxic activity in human cancer cell lines against colon adenocarcinoma (HCT-15), mammary adenocarcinoma (MCF-7), and lung adenocarcinoma (SKLU-1) was found comparable ((DAC)2Mg), or ca. 2-fold higher ((DAC)2Zn) than cisplatin. The acute toxicity assays indicate class 5 toxicity, according to the Organization for Economic Co-operation and Development (OECD) guidelines at doses of 3 g/kg for all complexes. No mortality or changes in the behavior of animals in any of the treated groups was observed. A therapeutic potential can be envisaged from the relevant cytotoxic activity upon human cancer cell lines in vitro and the undetected in vivo acute toxicity of these compounds.

An In Vitro Study on Mitochondrial Compensatory Response Induced by Gliadin Peptides in Caco-2 Cells

Dietary gliadin may show a broad spectrum of toxicity. The interplay between mitochondria and gliadin-induced oxidative stress has not been thoroughly examined in the intestinal epithelium. In this kinetic study, Caco-2 cells were exposed for 24 h to pepsin-trypsin-digested gliadin, alone or in combination with the antioxidant 2,6-di-tbutyl-p-cresol (BHT), and the effects on mitochondrial biogenesis and mtDNA were studied. Cells ability to recover from stress was determined after 24 h and 48 h of incubation in the culture medium. Gliadin-induced oxidative stress evoked a compensatory response. The stressor triggered a rapid and significant increase of Peroxisome proliferator-activated receptor γ coactivator-1alpha (PGC-1α) and Peroxiredoxin III (PrxIII) proteins, and mtDNA amount. As for the effects of gliadin on mtDNA integrity, strand breaks, abasic sites, and modified bases were analyzed in three mtDNA regions. D-loop appeared a more fragile target than Ori-L and ND1/ND2. The temporal trend of the damage at D-loop paralleled that of the amount of mtDNA. Overall, a trend toward control values was shown 48 h after gliadin exposure. Finally, BHT was able to counteract the effects of gliadin. Results from this study highlighted the effects of gliadin-induced oxidative stress on mitochondria, providing valuable evidence that might improve the knowledge of the pathophysiology of gluten-related disorders.

The Choice of Animal Model and Reduction

Careful choice of the animal model is essential, if research is to be conducted efficiently, by using the minimum number of animals in order to provide the maximum amount of information. Inbred strains of rodents provide an excellent way of controlling and investigating genetic variation in characters of interest and in response to experimental treatments. Outbred stocks, in which genetic and non-genetic factors are inextricably mixed, are much less suitable, because random and uncontrolled genetic variation tends to obscure any treatment responses. In some cases, the use of inbred strains has led to major advances in scientific understanding. The specific example given here is in the understanding of host–parasite relationships but, more generally, inbred strains have been of critical importance in research which has resulted in the award of at least 17 Nobel prizes. And yet, despite the extensive literature on the properties and scientific value of inbred strains, many scientists continue to use outbred stocks in the mistaken belief that the use of such animals will, in some mysterious way, make their research more applicable to humans. There is really no evidence that this is so, and there is much evidence that the use of inbred strains has been highly successful in many disciplines.

Chemo-Enzymatic Synthesis of Renewable Sterically-Hindered Phenolic Antioxidants with Tunable Polarity from Lignocellulose and Vegetal Oil Components

Despite their great antioxidant activities, the use of natural phenols as antioxidant additives for polyolefins is limited owing to their weak thermal stability and hydrophilic character. Herein, we report a sustainable chemo-enzymatic synthesis of renewable lipophilic antioxidants specifically designed to overcome these restrictions using naturally occurring ferulic acid (found in lignocellulose) and vegetal oils (i.e., lauric, palmitic, stearic acids, and glycerol) as starting materials. A predictive Hansen and Hildebrand parameters-based approach was used to tailor the polarity of newly designed structures. A specific affinity of Candida antarctica lipase B (CAL-B) towards glycerol was demonstrated and exploited to efficiently synthesized the target compounds in yields ranging from 81 to 87%. Antiradical activity as well as radical scavenging behavior (H atom-donation, kinetics) of these new fully biobased additives were found superior to that of well-established, commercially available fossil-based antioxidants such as Irganox 1010^® and Irganox 1076^®. Finally, their greater thermal stabilities (302 < T_d5% < 311 °C), established using thermal gravimetric analysis, combined with their high solubilities and antioxidant activities, make these novel sustainable phenolics a very attractive alternative to current fossil-based antioxidant additives in polyolefins.

Effect of Reduced Glutathione, Water Soluble Vitamin E Analogue and Butylated Hydroxytoluene on the Post Thaw Characteristics of Boar Spermatozoa

BACKGROUND

Antioxidant in freezing extender of boar semen improved post thaw sperm function.

OBJECTIVE

The study compared the effects of reduced glutathione (GSH), water soluble vitamin E analogue Trolox and butylated hydroxytoluene (BHT) on quality of cryopreserved boar spermatozoa.

MATERIALS AND METHODS

Using split sample technique three different antioxidants namely, GSH (1 mM), vitamin E (0.2 mM) and BHT (0.2 mM) were added to the freezing medium of lactose-egg yolk-glycerol extender, and samples were frozen using controlled freezing rate of 40°C/min from -6 to -140°C. Samples were evaluated for sperm motility, acrosomal status, plasma membrane integrity, mitochondrial membrane potential, lipid peroxidation and sperm DNA integrity after equilibration and after freezing.

RESULTS

The supplementation of GSH, vitamin E and BHT resulted in significantly higher post thaw motility, live intact acrosome and plasma membrane intact sperm. The incidence of post thaw sperm lipid peroxidation was significantly reduced after addition of antioxidants. However, antioxidants treatment neither significantly improved mitochondrial membrane potential of live sperm sub-population nor sperm DNA integrity after freezing. There was no significant difference of the post thaw sperm characteristics among three antioxidants. Protective effect of GSH, vitamin E and BHT are comparable on cryopreserved boar spermatozoa.

Neuroprotective effect of Bacopa monnieri against morphine-induced histopathological changes in the cerebellum of rats

Opioid addiction is associated with oxidative cell injury in neuronal cells. In this study, Bacopa monnieri (L.), a reputed nootropic plant, was evaluated against morphine-induced histopathological changes in the cerebellum of rats. B. monnieri methanolic extract (mBME) (40 mg/kg, p.o) and ascorbic acid (50 mg/kg, i.p) were administered two hours before morphine (20 mg/kg, i.p) for 14 and 21 days. The in vitro antioxidant activity of mBME was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging assay. Morphine produced vacuolization of basket and stellate cells and reduced the size of Purkinje cells in the cerebellum after 14 days. However, treatment for 21 days was associated with severe shrinkage of Purkinje cells with loss of their characteristic flask-shaped appearance as well as degeneration of basket, stellate and granule cells. Pretreatment with mBME and ascorbic acid for 14 and 21 days attenuated the morphine-induced histopathological changes in the cerebellum. The EC50 for the DPPH free-radical scavenging assay of mBME (39.06 μ/mL) as compared to ascorbic acid (30.25 μ/mL) and BHT (34.34 μ/mL) revealed that mBME strongly scavenged the free-radicals and thus possessed an efficient antioxidant propensity. These results concluded that B. monnieri having strong antioxidant activity exerted a protective effect against morphineinduced cerebellar toxicity.

Antioxidant activity of rosemary essential oil fractions obtained by molecular distillation and their effect on oxidative stability of sunflower oil

The objective of this study was to evaluate the antioxidant activity of rosemary essential oil fractions obtained by molecular distillation (MD) and investigate their effect on the oxidative stability of sunflower oil. MD fractions were prepared in a series of low-pressure stages where rosemary essential oil was the first feed. Subsequently, a distillate (D1) and residue (R1) were obtained and the residue fraction from the previous stage used as the feed for the next. The residue fractions had the largest capacity to capture free radicals, and the lowest peroxide values, conjugated dienes and conjugated trienes. The antioxidant activity of the fractions was due to oxygenated monoterpenes, specifically α-terpineol and cis-sabinene hydrate. Oxidative stability results showed the residues (R1 and R4) and butylated hydroxytoluene had greater antioxidant activity than either the distillate fractions or original rosemary essential oil. The residue fractions obtained by short path MD of rosemary essential oil could be used as a natural antioxidants by the food industry.

Proximate composition, phenolic content and in vitro antioxidant activity of aqueous extracts of the seaweeds Ascophyllum nodosum, Bifurcaria bifurcata and Fucus vesiculosus. Effect of addition of the extracts on the oxidative stability of canola oil under accelerated storage conditions

Extracts from three macroalgae species (Ascophyllum nodosum (ANE), Bifurcaria bifurcata (BBE) and Fucus vesiculosus (FVE)) were tested for proximate composition (total solid, protein and total carbohydrate contents), total phenols content (TPC), and for their antioxidant activities in vitro in comparison to that of BHT compound by using four different assays (ABTS radical cation decolouration, DPPH free radical scavenging activity, ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC)). The inclusion of the extracts as oil stabilizers in canola oil in substitution of the synthetic antioxidant (BHT) was also evaluated by assessing lipid oxidation parameters (peroxide value (PV), p-anisidine value (AV), TBARS value, conjugated dienes (CD) and TOTOX index) under accelerated storage conditions (16days, 60°C). There was an inverse relationship between total solid content and total polyphenols content in the seaweed extracts. FVE showed an intermediate TPC (1.15g PGE/100g extract), but it presented the highest in vitro antioxidant activity when measured using the ABTS, DPPH and FRAP tests. BBE, that displayed the highest TPC (1.99g PGE/100g extract), only showed the highest in vitro antioxidant activity when measured using the ORAC test. ANE showed the lowest TPC and the lowest antioxidant activity in all the tests performed. The seaweed extracts added in a 500ppm concentration significantly reduced the oxidation during canola oil storage at 60°C, being this antioxidant effect significantly higher than that of BHT added at 50ppm. Results indicate that seaweed extracts can effectively inhibit the oxidation of canola oil and they can be a healthier alternative to the synthetic antioxidants in the oil industry.

Assessment of the antioxidant activity of Bifurcaria bifurcata aqueous extract on canola oil. Effect of extract concentration on the oxidation stability and volatile compound generation during oil storage

In this research the antioxidant activity of water extracts of Bifurcaria bifurcata (BBE) at different dose against butylated hydroxytoluene (BHT) was evaluated in canola oil. Water extracts were firstly characterized in terms of total solid and polyphenolic compound contents, and their antioxidant activity together with that of BHT was evaluated using several in vitro tests (DPPH, ABTS, ORAC and FRAP). Next, the progress of lipid oxidation was assessed in canola oil added with five BBE concentrations (200, 400, 600, 800 and 1000ppm) and two BHT concentrations (50 and 200ppm) using an accelerated oxidation test. The progress in lipid oxidation was monitored by assessing some chemical indices (peroxide value, p-anisidine value, and conjugated dienes) during oil storage and some volatile compounds at the end of the storage period. BBE showed a significant antioxidant effect, being this ability concentration-dependent. The extent of lipid oxidation was inversely related to BBE dose, specially with regard to primary oxidation products. At the highest level of BBE, significant decreases of primary and secondary oxidation products, with respect to the control, were obtained with reduction percentages of 71.53%, 72.78%, 68.17% and 71.3% for peroxides, conjugated dienes, p-anisidine and TOTOX values, respectively. A level of 600ppm or higher concentration of the extract inhibits the lipid oxidation in a similar way than BHT at 200ppm. Regarding the inhibition of the formation of volatile compounds, both BBE and BHT strongly inhibited the formation of volatiles during oil storage, being this inhibition similar for all the concentrations of BBE and BHT essayed. Overall, results indicated that BBE can be used as a potential natural additive for improving oxidative stability of canola oil.

Stabilization studies of sunflower oil with antioxidants extracted from green and black cardamom

Extracts from green and black cardamom have been used to evaluate their antioxidant potential for sunflower oil samples for a period of 45 days. Synthetic antioxidants BHA/ BHT were also used parallel over a period of 45 days for comparison. Antioxidant potential of natural and synthetic antioxidants were evaluated by measuring free fatty acids (FFA), peroxide value (PV) and iodine value (IV) values by ambient storage of sunflower oil. The results showed that green cardamom extracts were more effective compared to black cardamom extracts. However compared to BHA and BHT (200ppm), these were found to be effective at higher concentrations.

In vitro Estrogenicity of Resin Composites

Previously, we have reported that sealants incorporating bisphenol A dimethacrylate showed estrogenicity by a reporter gene assay. This study tested the hypothesis that commercial composites, which contain various monomers and additives, exhibit estrogenic activity in vitro. The estrogenic activities of eluates obtained from 24 composites and 18 chemicals identified from the composites tested were examined with the use of the reporter gene assay. Among the 24 composites, 6 products were estrogenic, and among the 18 constituents, 1 photostabilizer, 2-hydroxy-4-methoxy-benzophenone (HMBP), 1 photoinitiator, 2,2-dimethoxy-2-phenyl-acetophenone (DMPA), and 1 inhibitor, 2,6-di- tert-butyl- p-cresol (BHT) had significant estrogenic activity. The concentration of HMBP in 4 estrogenic eluates was greater than the minimum concentration required for estrogenicity, and DMPA was found at a higher level than the minimum estrogenic concentration in the remaining 2 estrogenic specimens. These results suggest that the observed estrogenic activity of 6 composites is associated with the elution of either HMBP or DMPA.

Differential innate immune cell signatures and effects regulated by toll-like receptor 4 during murine lung tumor promotion

Tumor promotion is an early and critical stage during lung adenocarcinoma (ADC). We previously demonstrated that Tlr4 mutant mice were more susceptible to butylated hydroxytoluene (BHT)-induced pulmonary inflammation and tumor promotion in comparison to Tlr4-sufficient mice. Our study objective was to elucidate the underlying differences in Tlr4 mutant mice in innate immune cell populations, their functional responses, and the influence of these cellular differences on ADC progenitor (type II) cells following BHT-treatment. BALB (Tlr4-sufficient) and C.C3-Tlr4(Lps-d)/J (BALB(Lpsd); Tlr4 mutant) mice were treated with BHT (promoter) followed by bronchoalveolar lavage (BAL) and flow cytometry processing on the lungs. ELISAs, Club cell enrichment, macrophage function, and RNA isolation were also performed. Bone marrow-derived macrophages (BMDM) co-cultured with a type II cell line were used for wound healing assays. Innate immune cells significantly increased in whole lung in BHT-treated BALB(Lpsd) mice compared to BALB mice. BHT-treated BALB(Lpsd) mice demonstrated enhanced macrophage functionality, increased epithelial wound closure via BMDMs, and increased Club cell number in BALB(Lpsd) mice, all compared to BALB BHT-treated mice. Cytokine/chemokine (Kc, Mcp1) and growth factor (Igf1) levels also significantly differed among the strains and within macrophages, gene expression, and cell surface markers collectively demonstrated a more plastic phenotype in BALB(Lpsd) mice. Therefore, these correlative studies suggest that distinct innate immune cell populations are associated with the differences observed in the Tlr4-mutant model. Future studies will investigate the macrophage origins and the utility of the pathways identified herein as indicators of immune system deficiencies and lung tumorigenesis.

SIGNAL MEDIATORS AT INDUCTION OF HEAT RESISTANCE OF WHEAT PLANTLETS BY SHORT-TERM HEATING

The effects of functional interplay of calcium ions, reactive oxygen species (ROS) and nitric oxide (NO) in the cells of wheat plantlets roots (Triticum aestivum L.) at the induction of their heat resistance by a short-term influence of hyperthermia (heating at the temperature of 42 degrees C during 1 minute) have been investigated. The transitional increase of NO and H2O2 content, invoked by heating, was suppressed by the treatment of plantlets with the antagonists of calcium EGTA (chelator of exocellular calcium), lanthanum chloride (blocker of calcium channels of various types) and neomycin (inhibitor of phosphatidylinositol-dependent phospholipase C). The rise of hydrogen peroxide content, caused by hardening, was partially suppressed by the action of inhibitors of nitrate reductase (sodium wolframate) and NO-synthase (N(G)-nitro-L-arginine methyl ester--L-NAME), and the increasing of nitric oxide content was suppressed by the treatment of plants with the antioxidant ionol and with the scavenger of hydrogen peroxide (dimethylthiourea). These compounds and antagonists of calcium also partially removed the effect of the rise of plantlets' heat resistance, invoked by hardening heating. The conclusion on calcium's role in the activation of enzymatic systems, generating reactive oxygen species and nitric oxide, and on the functional interplay of these signal mediators at the induction of heat resistance of plantlets by hardening heating is made.

Effect of oxidant stressors and phenolic antioxidants on the ochratoxigenic fungus Aspergillus carbonarius

BACKGROUND

There are few studies dealing with the relationship between oxidative stress and ochratoxin A (OTA) biosynthesis. In this work, we analyzed the effect of the oxidant stressor menadione and the antioxidants 3,5-di-tert-butyl-4-hydroxytoluene (BHT), catechin, resveratrol and a polyphenolic extract on growth, generation of reactive oxygen species (ROS), OTA production and gene expression of antioxidant enzymes of Aspergillus carbonarius.

RESULTS

Exposure to menadione concentrations higher than 20 µmol L(-1) led to increases in ROS and OTA levels and a decrease in growth rate. Exposure to 2.5-10 mmol L(-1) BHT also led to higher ROS and OTA levels, although growth rate was only affected above 5 mmol L(-1). Naturally occurring concentrations of catechin, resveratrol and polyphenolic extract barely affected growth rate, but they produced widely different effects on OTA production level depending on the antioxidant concentration used. In general, gene expression of antioxidant enzymes superoxide dismutase (SOD) and peroxiredoxin (PRX) was downregulated after exposure to oxidant and antioxidant concentrations that enhanced OTA production level.

CONCLUSION

Aspergillus carbonarius responds to oxidative stress, increasing OTA production. Nevertheless, the use of naturally occurring concentrations of antioxidant phenolic compounds to reduce oxidative stress is not a valid approach by itself for OTA contamination control in grapes.

Understanding the chemistry behind the antioxidant activities of butylated hydroxytoluene (BHT): a review

Hindered phenols find a wide variety of applications across many different industry sectors. Butylated hydroxytoluene (BHT) is a most commonly used antioxidant recognized as safe for use in foods containing fats, pharmaceuticals, petroleum products, rubber and oil industries. In the past two decades, there has been growing interest in finding novel antioxidants to meet the requirements of these industries. To accelerate the antioxidant discovery process, researchers have designed and synthesized a series of BHT derivatives targeting to improve its antioxidant properties to be having a wide range of antioxidant activities markedly enhanced radical scavenging ability and other physical properties. Accordingly, some structure-activity relationships and rational design strategies for antioxidants based on BHT structure have been suggested and applied in practice. We have identified 14 very sensitive parameters, which may play a major role on the antioxidant performance of BHT. In this review, we attempt to summarize the current knowledge on this topic, which is of significance in selecting and designing novel antioxidants using a well-known antioxidant BHT as a building-block molecule. Our strategy involved investigation on understanding the chemistry behind the antioxidant activities of BHT, whether through hydrogen or electron transfer mechanism to enable promising anti-oxidant candidates to be synthesized.

Anti-inflammatory activity of the artificial antioxidants 2-tert-butyl-4-methoxyphenol (BHA), 2,6-di-tert-butyl-4-methylphenol (BHT) and 2,4,6-tri-tert-butylphenol (TBP), and their various combinations

BACKGROUND/AIM

The artificial complex phenols, 2-tert-butyl-4-methoxyphenol (BHA), 2,6-di-tert-butyl-4-methylphenol (BHT) and 2,4,6-tri-tert-butylphenol (TBP) exert efficient antioxidant activity; however, they are considerable toxic and potentially tumor-promoting. These phenols, particularly in combinations, have enhanced antioxidant activity due to synergistic interactions and produce bioactive intermediates such as quinone methide. We investigated the anti-inflammatory activity of BHA, BHT and TBP, and combinations of BHT/BHA (in molar ratios of 1:1, 1:2, 1:3 and 2:1), BHT/TBP (1:1), and BHA/TBP (1:1), using gene-expression systems for cyclooxygenase-2 (Cox2) and tumor necrosis facto-alpha (Tnfa) in RAW264.7 cells.

MATERIALS AND METHODS

The inhibitory effects of BHA, BHT and TBP on expression of Cox2 and Tnfa genes upon stimulation with Escherichia coli lipopolysaccharide (LPS) or Porphyomonas gingivalis (Pg) fimbriae were determined using real-time polymerase chain reaction.

RESULTS

The inhibitory effect on expression of Cox2 and Tnfa genes upon stimulation with LPS and fimbriae was greatly enhanced by the combination of two antioxidants (molar ratio 1:1), BHT/BHA. In addition, that of the Cox2 gene, but not of Tnfa gene was slightly enhanced by a combination of equimolar BHT/TBP and BHA/TBP. None of the antioxidants alone exerted any anti-inflammatory activity upon stimulation with LPS, but a slight anti-inflammatory activity was observed upon stimulation with Pg fimbriae. The inhibitory effect of the BHT/BHA combination on expression of Cox2 mRNA upon stimulation with LPS was investigated at afferent molar ratios, and a molar ratio of 1:1 was found to have considerably less effect than a molar ratio of 1:2 or 2:1. The 1:3 combination had no effect.

CONCLUSION

The combination of BHT and BHA at a molar ratio of 0.5-2 exerts potent anti-inflammatory activity. This anti-inflammatory activity on the generation of inflammatory mediators in LPS-activated RAW264.7 cells may be attributable to complex synergistic antioxidant activity of the combination of BHT and BHA. Our results suggest the potential usefulness of the BHT/BHA combination at an appropriate molar ratio as an antioxidant in foods and pharmaceuticals, whereas either antioxidant alone is unlikely to be effective.

[Reactive oxygen forms and Ca ions as possible intermediaries under the induction of heat resistance of plant cells by jasmonic acid]

The participation of reactive oxygen species (ROS) and calcium ions in realization of influence of exogenous jasmonic acid (JA) on the heat resistance of wheat coleoptiles has been investigated. Influence of 1 microM JA caused the transitional intensifying of generation of superoxide anion-radical (O2*-) and hydrogen peroxide in coleoptiles with the maximum within 15-30 minutes after the treatment beginning. Within the first hour after the beginning of coleoptiles treatment with JA the increase of superoxide dismutase (SOD) activity was noted. Later on (within 5-24 hours after the treatment beginning) there was the lowering of ROS generation by coleoptiles of experimental variant, and the SOD activity approached the control value. Intensifying of generation of superoxide radical induced by JA was suppressed by the antioxidant ionol and was partially levelled by imidazole (inhibitor of NADPH-oxidase), EGTA (chelator of extracellular calcium) and lanthanum chloride (calcium channels blocker). Pretreatment of coleoptiles with the ionol, imidazole, EGTA and LaC3l3 also partially removed the effect of increase of their resistance to the damaging heating caused by exogenous JA. It is supposed that the ROS generated with participation NADPH-oxidase, which activity depends on the receipt of calcium ions from extracellular space in the cytosol, are involved in realization of physiological effects of JA.

Survival and Fertility of Boar Spermatozoa After Freeze-Thawing in Extender Supplemented With Butylated Hydroxytoluene

This study evaluated the protective effect of butylated hydroxytoluene (BHT), a lipid-soluble antioxidant, against cryopreservation injuries to boar spermatozoa. In experiment 1, the lowest BHT concentrations able to reduce lipid peroxidation in boar spermatozoa were determined. Nine BHT concentrations (ranging from 0.025 to 3.2 mM) were evaluated, and the lowest (P <.05) production of malondialdehyde (MDA), as an indicator of lipid peroxidation, was obtained when BHT ranged from 0.2 to 1.6 mM. In experiment 2, sperm survivability was evaluated when BHT was added to a postthaw freezing extender by measuring the degree of sperm lipid peroxidation (using MDA production) and by measuring parameter such as motility, plasma membrane and acrosome integrity, and cell apoptosis. The ability of thawed spermatozoa to fertilize in vitro-matured oocytes and of embryos to develop to the blastocyst stage in vitro was also assessed. Pooled sperm-rich fractions collected from 3 mature Pietrain boars were frozen in 0.5-mL straws after dilution with lactose-egg yolk-glycerol-Orvus ES Paste extender supplemented with 0, 0.2, 0.4, 0.8, and 1.6 mM BHT. Postthaw sperm survival, evaluated 30 and 150 minutes after thawing, was higher in BHT-treated spermatozoa, being significant (P <.05) when the freezing extender was supplemented with 0.2, 0.4, and 0.8 mM BHT. The addition of BHT to the freezing extender resulted in a significant (P <.05) decrease in the MDA concentration in thawed spermatozoa, irrespective of the level of BHT used. BHT had no effect on oocyte cleavage rates, but the development to blastocyst was improved for embryos derived from spermatozoa frozen in extender supplemented with 0.4 mM BHT (16% vs 29% of blastocysts per total oocytes; P <.05). In conclusion, under the conditions tested in the present study, the addition of BHT to the freezing extender improved the overall efficiency of thawed boar spermatozoa.

Environmental and seasonal influences on red raspberry flavour volatiles and identification of quantitative trait loci (QTL) and candidate genes

Raspberry volatiles are important for perceptions of sensory quality, mould resistance and some have nutraceutical activities. Twelve raspberry character volatiles were quantified, 11 of them in fruit from two seasons, from plants from the Glen Moy × Latham mapping population growing in both open field and under cover (polytunnels). Effects of season and environment were examined for their impact on the content of α-ionone, α-ionol, β-ionone, β-damascenone, linalool, geraniol, benzyl alcohol, (Z)-3-hexenol, acetoin, acetic and hexanoic acids, whilst raspberry ketone was measured in one season. A significant variation was observed in fruit volatiles in all progeny between seasons and method of cultivation. Quantitative trait loci were determined and mapped to six of the seven linkage groups, as were candidate genes in the volatiles pathways.

Stability and antioxidant activity of semi-synthetic derivatives of 4-nerolidylcatechol

4-nerolidylcatechol (4-NC) is an unstable natural product that exhibits important antioxidant, anti-inflammatory and other properties. It is readily obtainable on a multi-gram scale through straightforward solvent extraction of the roots of cultivated Piper peltatum or P. umbellatum, followed by column chromatography on the resulting extract. Semi-synthetic derivatives of 4-NC with one or two substituent groups (methyl, acetyl, benzyl, benzoyl) on the O atoms have been introduced that have increased stability compared to 4-NC and significant in vitro inhibitory activity against the human malaria parasite Plasmodium falciparum. Antioxidant and anti-inflammatory properties may be important for the antiplasmodial mode of action of 4-NC derivatives. Thus, we decided to investigate the antioxidant properties, cytotoxicity and stability of 4-NC derivatives as a means to explore the potential utility of these compounds. 4-NC showed high antioxidant activity in the DPPH and ABTS assays and in 3T3-L1 cells (mouse embryonic fibroblast), however 4-NC was more cytotoxic (IC₅₀ = 31.4 µM) and more unstable than its derivatives and lost more than 80% of its antioxidant activity upon storage in solution at −20 °C for 30 days. DMSO solutions of mono-O-substituted derivatives of 4-NC exhibited antioxidant activity and radical scavenging activity in the DPPH and ABTS assays that was comparable to that of BHA and BHT. In the cell-based antioxidant model, most DMSO solutions of derivatives of 4-NC were less active on day 1 than 4-NC, quercetin and BHA and more active antioxidants than BHT. After storage for 30 days at −20 °C, DMSO solutions of most of the derivatives of 4-NC were more stable and exhibited more antioxidant activity than 4-NC, quercetin and BHA and exhibited comparable antioxidant activity to BHT. These findings point to the potential of derivatives of 4-NC as antioxidant compounds.

[Comparison of the antiradical activity of ionol, components of fresh ginger, and its extracts]

The antiradical properties of three samples of ginger (Zingiber officinale R.)-juice from fresh rhizome, essential oil, and extracts (oleoresin)-were studied and compared with the properties of synthetic antioxidant ionol (butylatedhydroxy-toluene, BHT). Reaction antioxidants with stable free 2,2-diphenyl-1-picrylhydrozyl radicals were used as model systems. DPPH equivalents per gram of ginger sample, EC50, and antiradical efficiency (AE) were determined. The EC50 and AE values for ginger oleoresin and BHT were similar. They were the same as those of highly active natural antioxidants, and the values for essential oil and ginger juice were lower by two orders of magnitude. On the base of kinetic parameters, the ginger samples may belong to antiradical compounds with prolonged action.

Effects of tert-butyl hydroperoxide on Ca(2+) ATPase activity in isolated rat hepatocytes and its reversal by antioxidants

Calcium ions play an importantrole in various physiological processes such as nerve impulse transmission, muscle contraction, hormone action, blood clotting. They ions act as an intracellular second messenger, relaying information within cells to regulate their activity. To understand the mechanism of hepatotoxicity of t-BHP, studies were carried out using freshly isolated rat hepatocytes. The effect of t-BHP on Ca(2+) accumulation and Ca(2+) uptake by rat hepatocytes was monitored using 45Ca(2+). It caused decrease in 15% accumulation of 45Ca(2+) in comparison to the control group. t-BHP also significantly decreased the Ca(2+) ATPase activity in isolated hepatocytes .This decrease in Ca(2+) ATPase activity by t-BHP was reversed 40% by naturally occurring antioxidant glutathione (GSH) and 20% by the synthetic antioxidant butylated hydroxy toluene (BHT). These results indicate that the hepatotoxic action of t-BHP involves oxidative stress as evident by the protection accorded by various antioxidants employed in the study as well as impairment of intracellular calcium homeostasis which can lead to liver cell injury.

Nutritive value of diets containing fish silage for juvenile Litopenaeus vannamei (Bonne, 1931)

BACKGROUND

Fish wastes has been used for many years as an alternative in feeds for aquaculture. In the present study weight gain of juvenile white shrimp Litopenaeus vannamei fed diets including fish waste silage (WS), fish waste silage with soybean meal SBM (WS + S) or fish waste meal (WM) was compared. A conventional acidic silage process was applied to obtain from wastes (skin, heads, bones and viscera) of snapper (Lutjanus spp.), grunt (Haemulon plumieri), and grouper (Epinephelus spp.) an ingredient rich in protein.

RESULTS

After 3 days ensilage more than 90% protein was hydrolysed. Waste material processed at pH 3.8 lost about 24% tryptophan. Butylated hydroxytoluene (BHT) prevented lipid oxidation, as shown after 45 days with malonaldehyde production. Shrimp fed WS + S diet gained 0.7 g per week higher than those fed WS and WM diets with 0.3 g per week (P < 0.05).

CONCLUSION

WS processed with formic acid under conditions of low pH is beneficial for the white shrimp L. vannamei. It sustained reasonable weight gain combined with soybean meal in practical diets. On the other hand, BHT addition was beneficial in preventing oxidative action during silage preparation.

Antioxidant activity of capsaicinoid in canola oil

Interest in replacing synthetic antioxidants, namely, butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA), with natural antioxidants is increasing. The present study examined the antioxidant activity of capsaicinoid from chili pepper in heated canola oil. The oxidation was conducted at 60, 90, 120, and 180 °C by monitoring oxygen consumption and the decrease in linoleic acid and α-linolenic acid in canola oil. At 60 °C, capsaicinoid was more effective against oxidation of canola oil compared with BHT. At higher temperatures of 90, 120, and 180 °C, capsaicinoid possessed an antioxidant activity similar to or slightly weaker that that of BHT. It was found that capsaicinoid prevented canola oil from oxidation in a dose-dependent manner. To study the structure-antioxidant relationship, it was found that the trimethylsiloxy (TMS) derivatives of capsaicinoid did not exhibit any antioxidant activity, suggesting the hydroxyl moiety was the functional group responsible for the antioxidant activity of capsaicinoid. It was concluded that capsaicinoid had the potential to be further explored as a natural antioxidant in foods, particularly spicy foods.

Effect of butylated hydroxytoluene (BHT) on the aerobic biodegradation of a model vegetable oil in aquatic media

Antioxidants added to vegetable oils to prevent lipid oxidation significantly affect their biodegradation in impacted aquatic environments. In this study, the effect of butylated-hydroxytoluene (BHT) on the biodegradation of glyceryl trilinoleate, a model vegetable oil highly susceptible to autoxidation, was determined. Biodegradation experiments were conducted in respirometric microcosms at an oil loading of 333 gal acre(-1) (0.31 L m(-2)) and BHT concentrations ranging from 0 to 800 mg kg(-1) (0, 50, 100, 200, 400, and 800 mg kg(-1)). Competition between polymerization and biodegradation of the oil was observed at all BHT concentrations and was significant in the microcosms not supplemented with the antioxidant. In all microcosms, intractable rigid polymers unavailable for bacterial degradation were formed. Infrared analysis evidenced the advanced stages of the oil autoxidation. After 19 weeks of incubation, only about 41% of the oil was mineralized in the microcosms with no BHT. However, mineralization exceeded 67% in the microcosms with added antioxidant and did not significantly increase with increasing BHT concentrations. Biodegradation rate constants were calculated by nonlinear regression and were not significantly different in the microcosms with added BHT (k = 0.001 h(-1)). Higher k values were measured in the microcosms lacking the antioxidant (k = 0.0023 h(-1)), most likely due to the increased oxygen consumption associated with the autoxidation process in this case. No toxicity was detected in all biotic microcosms at the end of the incubation period, while high toxicity (EC(50) = 4.78%) was measured in the abiotic blanks with no antioxidant and was attributed to the accumulation of autoxidation products.

Mycoflora and ochratoxin a control in wheat grain using natural extracts obtained from wine industry by-products

The aim of this study was to evaluate the effect of some natural extracts obtained from grape pomace (GPE) and grape seeds (GSE) as compared to a synthetic food, antioxidant-butylated hydroxytoluene (BHT), in order to control fungal population and ochratoxin A (OTA) production in naturally contaminated wheat. The results showed that the addition of these extracts was efficient with OTA content decreasing. On treatment with these extracts the loss of OTA content after 14 days was in the range 7.8-28.3% relative to the control sample, but increased up to 26.48-37% after 28 days. The highest loss in OTA content was recorded for treatment with GPE at the 500 ppm level. Regarding the fungal development, the obtained results show that the total fungal populations were significantly reduced by using natural extracts. The most efficient extract was GPE. Both BHT and GPE inhibit the growth of Penicillium verrrucosum, for all doses, but less with Aspergillus genera. GPE affects the growth of other types of moulds such as Rhizopus microsporus, Fusarium graminearum, Alternaria infectoria and Cladosporium herbarum. Our data suggested that GPE and GSE are able to provide fungicidal and fungistatic protection and to control the OTA accumulation in wheat, at least in a similar manner to BHT.

Effect of butylated hydroxytoluene (E321) pretreatment versus L-arginine on liver injury after sub-lethal dose of endotoxin administration

Aim of this study was to compare the effects of L-arginine (L-arg) and food-antioxidant butylated hydroxytoluene (BHT) against oxidative stress of Escherichia coli endotoxin (LPS) in liver. Ninety Wistar albino rats were assigned in three groups. Rats received one of the following pre-treatment previous to 5mg/kg LPS intraperitoneally: saline, L-arg (NO donor, 100mg/kg) or BHT (250 mg/kg/day), for 3 days. At second, fourth and sixth hours, plasma nitrite-plus-nitrate, circulating liver enzymes, glutathione levels, superoxide dismutase, glutathione peroxidase activities were measured. The most remarkable liver injury was evident in BHT pre-treated animals at all time points compared to L-arg pre-treated rats. While BHT enhanced superoxide dismutase activities following LPS, glutathione decreased simultaneously compared to L-arg group. Although the risk associated with the use of BHT alone in subthreshold doses appeared to be low, higher risk of liver toxicity should be considered when over-consuming this food additive in endotoxemic settings.

Response surface optimisation of extraction of antioxidants from strawberry fruit, and lipid peroxidation inhibitory potential of the fruit extract in cooked chicken patties

BACKGROUND

Strawberries contain high levels of antioxidants and have beneficial effects against oxidative stress-mediated diseases, such as cancer. They contain multiple phenolic compounds, which contribute to their biological properties. Hence, a study was carried out to optimise the extraction of antioxidants and evaluate the antioxidant potential of strawberry fruit extract (SE) in cooked chicken patties during refrigerated storage. The activity of SE was compared with that of butylhydroxytoluene (BHT).

RESULTS

The effect of solvent type (MeOH and EtOH), concentration (0-70%) of EtOH in the system, temperature (30-60 °C), and time (30-150 min) on DPPH•-scavenging activity of SE was investigated. Response surface methodology was used to estimate the optimum extraction conditions for each parameter. The maximum predicted DPPH• scavenging under the optimised conditions (100% MeOH, 30 °C, 150 min) was 43% at 1 mg SE mL⁻¹. Freshly prepared chicken patties were treated with 5% and 10% SE and 2% BHT, and stored aerobically at 4 °C for 6 days. SE had no influence (P < 0.05) on any of the sensory attributes of the patties. The values of thiobarbituric acid reactive substances reduced significantly (P < 0.05) from 2.47 mg in control patties to 0.312 mg and 0.432 mg malonaldehyde kg⁻¹ sample in 5-SE and 10-SE patties, respectively, on the day 6 of storage.

CONCLUSION

The optimised model depicted MeOH at 30 °C with an extended time of 150 min as the optimum settings for extraction of compounds from strawberry that had the scavenging activity. The study shows that the extraction of natural antioxidants from strawberry can be improved by optimising several key extraction parameters. SE also acted as an effective antioxidant and suppressed lipid peroxidation in cooked chicken patties.

Antiradical, chelating and antioxidant activities of hydroxamic acids and hydroxyureas

Reactive oxygen species, along with reactive nitrogen species, may play an important role in the pathogenesis and progress of many diseases, including cancer, diabetes and sickle cell disease. It has been postulated that hydroxyurea, one of the main treatments in sickle cell disease, achieves its activity partly also through its antioxidant properties. A series of hydroxyurea derivatives of L- and D-amino acid amides and cycloalkyl-N-aryl-hydroxamic acids was synthesized and investigated for their radical scavenging activity, chelating properties and antioxidant activity. All the compounds showed exceptional antiradical activities. For example, free radical scavenging activities of investigated hydroxyureas were higher than the activity of standard antioxidant, butylated hydroxyanisole (BHA). Moreover, most of the investigated hydroxamic acids were stronger Fe²⁺ ion chelators than quercetin. In addition, the investigated compounds, especially hydroxamic acids, were proven to be excellent antioxidants. They were as effective as BHA in inhibiting β-carotene-linoleic acid coupled oxidation. It is reasonable to assume that the antioxidant activity of the investigated compounds could contribute to their previously proven biological properties as cytostatic and antiviral agents.

Oxidative stability of cooked, frozen, reheated beef patties: effect of antioxidants

BACKGROUND

The effect of selected antioxidants (grape seed extract (GS), oleoresin rosemary (OR), water-soluble oregano extract (WO), propyl gallate (PG), butylated hydroxyanisole (BHA)), butylated hydroxytoluene (BHT)) on sensory, color and oxidative stability of cooked, frozen, reheated ground beef patties was evaluated. Beef lean and trim were ground; antioxidants and salt were added. Patties were cooked (71 °C), overwrapped in commercial polyvinyl chloride film, and stored frozen (-18 °C), then evaluated monthly for 6 months. Flavor, odor and color were determined using a descriptive panel. Instrumental color was determined by a spectrocolorimeter. Lipid oxidation was determined using thiobarbituric acid reactive substances (TBARS).

RESULTS

After 6 months of storage, PG and GS samples had lower rancid odor scores and TBARS than controls. Control samples and those containing BHT did not differ statistically in sensory grassy or rancid odor, indicating that they were the most oxidized. TBARS correlated with grassy, rancid, cardboard and beef odors during the 6-month storage period.

CONCLUSIONS

Based on TBARS, the order of effectiveness of the antioxidants was PG and GS > OR > BHA > WO and BHT > control. TBARS were well correlated with sensory evaluations of odor and flavor. Antioxidants also protected a* values during storage.

[Comparative analysis of dimephosphon, ionol, and xydiphone effects on indomethacin-induced gastric lesions in rats]

Gastroprotective activity of dimephosphon, xydiphone, and ionol and their effects on the lipid peroxidation (LPO) indices and the activity of antioxidant enzymes in blood and organ tissues were studied on the model of indomethacin-induced gastric lesions in white rats. The indomethacin-induced gastropathy leads to increased concentration of LPO products in blood plasma and tissues. Dimephosphon and ionol reduced the number of gastric lesions and prevented LPO activation. In contrast, xydiphone administration had no effect on indometacin-induced gastric lesions and was accompanied by increased concentration of LPO products in the blood, liver, kidneys, spleen and stomachs of rats.

[The influence of N-, S-containing chinasolone derivatives (NC-224) on the biochemical and physicochemical parameters of membrane endoplasmatic reticulum and nuclear chromatine fractions of rats liver cells in conditions of its injury by tetrachloromethane]

Using biochemical and physicochemical methods of investigation in vivo, the effect of the substance NC-224, N-, S-chinasolone-derivative, on the lipoperoxidation activity in rat liver endoplasmatic reticulum membranes and nuclear chromatin fractions under tetrachloromethane intoxication have been studied. It was shown that NC-224 has pronounced antioxidant activity which is the biochemical basis of the substance membrane- and genome-protective effects and its ability to restore physicochemical properties of the surface and hydrophobic zones of hepatocyte membranes and structural parameter nuclear chromatin fractions in the conditions of chemical liver injury.

[Antioxidants inhibit the oxidative modification of high density lipoproteins]

OBJECTIVE

To study the role and mechanism of antioxidants on inhibiting oxidative modification of high density lipoproteins (HDL).

METHODS

Freshly prepared human plasma HDL was treated by incubation with copper ion, hyperchlorite or arterial wall cells. Compared to control, the test groups were treated with addition of different concentration of butylhydroxytoluene (BHT), vitamin C and vitamin E. Then, the relative electrophoretic mobility (REM), thiobarbituric acid-reactive substances (TBARS), ratio of lysolecithin to lecithin (LPC/PC), and lipoprotein moieties were investigated.

RESULTS

BHT, vitamin C and vitamin E can significantly inhibit the increasing REM, TBARS, LPC/PC ratio and lipoprotein variation that induced by copper ion and hyperchlorite and arterial wall cells. But these antioxidants act on different manner.

CONCLUSION

BHT, vitamin C and vitamin E can inhibit the oxidative modification of HDL and hence could be potential nutrients to prevent atherosclerosis.

Closure of VDAC causes oxidative stress and accelerates the Ca(2+)-induced mitochondrial permeability transition in rat liver mitochondria

The electron transport chain of mitochondria is a major source of reactive oxygen species (ROS), which play a critical role in augmenting the Ca(2+)-induced mitochondrial permeability transition (MPT). Mitochondrial release of superoxide anions (O(2)(-)) from the intermembrane space (IMS) to the cytosol is mediated by voltage dependent anion channels (VDAC) in the outer membrane. Here, we examined whether closure of VDAC increases intramitochondrial oxidative stress by blocking efflux of O(2)(-) from the IMS and sensitizing to the Ca(2+)-induced MPT. Treatment of isolated rat liver mitochondria with 5microM G3139, an 18-mer phosphorothioate blocker of VDAC, accelerated onset of the MPT by 6.8+/-1.4min within a range of 100-250microM Ca(2+). G3139-mediated acceleration of the MPT was reversed by 20microM butylated hydroxytoluene, a water soluble antioxidant. Pre-treatment of mitochondria with G3139 also increased accumulation of O(2)(-) in mitochondria, as monitored by dihydroethidium fluorescence, and permeabilization of the mitochondrial outer membrane with digitonin reversed the effect of G3139 on O(2)(-) accumulation. Mathematical modeling of generation and turnover of O(2)(-) within the IMS indicated that closure of VDAC produces a 1.55-fold increase in the steady-state level of mitochondrial O(2)(-). In conclusion, closure of VDAC appears to impede the efflux of superoxide anions from the IMS, resulting in an increased steady-state level of O(2)(-), which causes an internal oxidative stress and sensitizes mitochondria toward the Ca(2+)-induced MPT.

Effects of extensively oxidized low-density lipoprotein on mitochondrial function and reactive oxygen species in porcine aortic endothelial cells

Atherosclerotic cardiovascular disease is the leading cause of mortality in the Western world. Dysfunction of the mitochondrial respiratory chain and overproduction of reactive oxygen species (ROS) are associated with atherosclerosis and cardiovascular disease. Oxidation increases the atherogenecity of LDL. Oxidized LDL may be apoptotic or nonapoptotic for vascular endothelial cells (EC), depending on the intensity of oxidation. A previous study demonstrated that nonapoptotic oxidized LDL increased activity of mitochondrial complex I in human umbilical vein EC. The present study examined the impact of extensively oxidized LDL (eoLDL) on oxygen consumption and the activities of key enzymes in the mitochondrial respiratory chain of cultured porcine aortic EC. Oxygraphy detected that eoLDL significantly reduced oxygen consumption in various mitochondrial complexes. Treatment with eoLDL significantly decreased NADH-ubiquinone dehydrogenase (complex I), succinate cytochrome c reductase (complex II/III), ubiquinone cytochrome c reductase (complex III), and cytochrome c oxidase (complex IV) activities and the NAD+-to-NADH ratio in EC compared with mildly oxidized LDL, LDL, or vehicle. Butylated hydroxytoluene, a potent antioxidant, normalized eoLDL-induced reductions in complex I and III enzyme activity in EC. Mitochondria-associated intracellular ROS and release of ROS from EC were significantly increased after eoLDL treatment. These findings suggest that eoLDL impairs enzyme activity in mitochondrial respiratory chain complexes and increases ROS generation from mitochondria of arterial EC. Collectively, these effects could contribute to vascular injury and atherogenesis under conditions of hypercholesterolemia and oxidative stress.

Oxidation of cholesterol and beta-sitosterol and prevention by natural antioxidants

Consumption of cholesterol oxidation products (COPs) is a growing health concern, but little is known about the intake of beta-sitosterol oxidation products (SOPs). The present study was performed (i) to compare the oxidative stability of cholesterol with that of beta-sitosterol; (ii) to investigate the oxidative pattern of cholesterol and beta-sitosterol in lard, corn oil, and olive oil; and (iii) to examine the effectiveness of green tea catechins (GTC), alpha-tocopherol, and quercetin in prevention of cholesterol and beta-sitosterol oxidation compared with butylated hydroxytoluene (BHT). Results showed both cholesterol and beta-sitosterol were thermally unstable with 75% of cholesterol and beta-sitosterol being oxidized at 180 degrees C for 2 h. The oxidation behavior of beta-sitosterol was similar to that of cholesterol in terms of oxidative rate and oxidation products. The major COPs produced were 7-ketocholesterol, 7alpha-hydroxycholesterol, 7beta-hydroxycholesterol 5,6alpha-epoxycholesterol, and 5,6beta-epoxycholesterol, whereas the major SOPs were 7-ketositosterol, 7alpha-hydroxysitosterol, 7beta-hydroxysitosterol, 5,6alpha-epoxysitosterol, and 5,6beta-epoxysitosterol. Under the same experimental conditions, both cholesterol and beta-sitosterol were oxidized more slowly in corn oil, lard, and olive oil, attributable to the unsaponified antioxidants present in these fat and oils. GTC, alpha-tocopherol, and quercetin were more effective than BHT in preventing the oxidation of cholesterol and beta-sitosterol.

Effect of protective compounds on the survival, electrolyte leakage, and lipid degradation of freeze-dried Weissella paramesenteroides LC11 during storage

The effect of cryoprotectants (maltodextrin+glycerol) and cryoprotectants+antioxidant [ascorbic acid and/or butylated hydroxytoluene (BHT)] mixtures on the survival, electrolyte leakage, and lipid degradation of freeze-dried Weissella paramesenteroides LC11 during storage was investigated and compared with that of the control (cells without additives) over a 90-day storage period at 4 or 20 degrees in glass tubes with water activity (a(w)) of 0.23. The survival, electrolyte leakage, and lipid degradation were evaluated through colony counts, electrical conductivity, and thiobarbituric acid reactive substances (TBARS) content, respectively. The fatty acids composition was determined by gas chromatography, in both the total lipid extract and the polar lipid fraction, and compared with that of the control after the 90-day storage period. As the storage proceeded, increases in leakage value and TBARS content, as well as a decrease in viability, were observed. After 90 days of storage, the major fatty acids found in both the total lipid extract and the polar lipid fraction were palmitic (16:0), palmitoleic (16:1), stearic (18:0), oleic (18:1), linoleic (18:2), and linolenic (18:3) acids. The survival, leakage value, TBARS content and 18:2/16:0 or 18:3/16:0 ratio were the greatest for the protected strain held at 4 degrees . Cells with the cryoprotectants+BHT mixture showed the highest percentage of survival and 18:2/16:0 or 18:3/16:0 ratio in both lipid extracts, as well as the lowest leakage value and TBARS content after the 90-day storage period. Drying cells with the cryoprotectants+BHT mixture considerably slowed down polar lipid degradation and loss of membrane integrity, resulting in improved viability during storage.

Oxidative stability of conjugated linolenic acids

Interest in conjugated linolenic acid (CLnA) and conjugated linoleic acid (CLA) as functional lipids is growing. The present study was (i) to study the oxidative stability of individual CLnA isomers and (ii) to compare the oxidative stabilities of CLnA and CLA with their corresponding nonconjugated counterparts, α-linolenic acid (LN) and linoleic acid (LA). The oxidation was carried out in air at 50 °C and monitored by the gas-liquid chromatography (GC) and the oxygen consumption test. First, it was found that CLnA was most unstable followed by CLA, LN, and LA in decreasing order. Second, analyses of silver ion high-performance liquid chromatography (Ag(+)-HPLC) demonstrated that t,t,t-CLnA isomers had greater stability than c,t,t-CLnA and c,t,c-CLnA isomers. Finally, both green tea catechins (GTCs) and butylated hydroxytoluene (BHT) were capable of preventing the CLnA oxidation, with the former being more effective than the latter.

Transmembrane signaling pathway mediates oxidized low-density lipoprotein-induced expression of plasminogen activator inhibitor-1 in vascular endothelial cells

Atherosclerotic cardiovascular disease is the number one cause of death for adults in Western society. Plasminogen activator inhibitor-1 (PAI-1), the major physiological inhibitor of plasminogen activators, has been implicated in both thrombogenesis and atherogenesis. Previous studies demonstrated that copper-oxidized low-density lipoprotein (C-oLDL) stimulated production of PAI-1 in vascular endothelial cells (EC). The present study examined the involvement of lectin-like oxidized LDL receptor-1 (LOX-1) and Ras/Raf-1/ERK1/2 pathway in the upregulation of PAI-1 in cultured EC induced by oxidized LDLs. The results demonstrated that C-oLDL or FeSO(4)-oxidized LDL (F-oLDL) increased the expression of PAI-1 or LOX-1 in human umbilical vein EC (HUVEC) or coronary artery EC (HCAEC). Treatment with C-oLDL significantly increased the levels of H-Ras mRNA, protein, and the translocation of H-Ras to membrane fraction in EC. LOX-1 blocking antibody, Ras farnesylation inhibitor (FTI-277), or small interference RNA against H-Ras significantly reduced C-oLDL or LDL-induced expression of H-Ras and PAI-1 in EC. Incubation with C-oLDL or F-oLDL increased the phosphorylation of Raf-1 and ERK1/2 in EC compared with LDL or vehicle. Treatment with Raf-1 inhibitor blocked Raf-1 phosphorylation and the elevation of PAI-1 mRNA level in EC induced by C-oLDL or LDL. Treatment with PD-98059, an ERK1/2 inhibitor, blocked C-oLDL or LDL-induced ERK1/2 phosphorylation or PAI-1 expression in EC. The results suggest that LOX-1, H-Ras, and Raf-1/ERK1/2 are implicated in PAI-1 expression induced by oxidized LDLs or LDL in cultured EC.

Antioxidant Activities of Essential Oil Mixtures toward Skin Lipid Squalene Oxidized by UV Irradiation

Antioxidant activities of essential oil mixtures--thyme or clove leaf with cinnamon leaf, rose, or parsley seed--toward skin lipid, squalene oxidized by UV irradiation were investigated using the malonaldehyde/gas chromatography assay. At all concentrations (50, 100, or 500 mug/mL) tested, thyme oil mixed with 500 mug/mL clove oil showed over 90% inhibitory effect against malonaldehyde formation. The order of potency of all oils mixed together at 500 mug/mL was thyme/clove leaf (93%) > clove leaf/parsley seed = clove leaf /rose (87%) > thyme/parsley seed (83%) > clove leaf/cinnamon leaf (77%) > thyme/parsley seed (71%) > thyme/cinnamon leaf (7%). In comparison, the inhibitory activities of 500 microg/mL of BHT or alpha-tocopheroltoward malonaldehyde formation were 85% and 76%, respectively. Pro-oxidant effects were observed for some mixtures of thyme with cinnamon leaf or rose oils. The potent antioxidant effects resulting from a mixture of thyme and clove leaf oils may be due to the presence of thymol and eugenol.

Antioxidant activity of L-adrenaline: a structure-activity insight

L-adrenaline belongs to a group of the compounds known as catecholamines, which play an important role in the regulation of physiological process in living organisms. The antioxidant activity and antioxidant mechanism of L-adrenaline was clarified using various in vitro antioxidant assays including 1,1-diphenyl-2-picryl-hydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), N,N-dimethyl-p-phenylenediamine (DMPD(+)), and superoxide anion radicals (O(2)(-)) scavenging activity, hydrogen peroxide (H(2)O(2)), total antioxidant activity, ferric ions (Fe(3+)) and cupric ions (Cu(2+)) reducing ability, ferrous ions (Fe(2+)) chelating activity. L-adrenaline inhibited 74.2% lipid peroxidation of a linoleic acid emulsion at 30 microg/mL concentration. On the other hand, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), alpha-tocopherol and trolox displayed 83.3, 82.1, 68.1 and 81.3% inhibition on the peroxidation of linoleic acid emulsion at the same concentration, respectively. BHA, BHT, alpha-tocopherol and trolox were used as reference antioxidants and radical scavenger compounds. Moreover, this study will bring an innovation for further studies related to antioxidant properties of L-adrenaline. According to present study, L-adrenaline had effective in vitro antioxidant and radical scavenging activity.

[Effects of ionol and alpha-tocopherol on lipid peroxidation in the liver of dogs with acute pancreatitis]

We studied effects of natural (alpha-tocopherol) and synthetic (ionol) antioxidants on lipid peroxidation (LPO) in the liver of dogs with acute experimental pancreatitis (AEP). In the first three days of experiment formation of DK was more strongly inhibited by alpha-tocopherol but after day 6--by ionol. Alpha-tocopherol more effectively inhibits formation of intermolecular connections of lipid peroxides at transition of DK in intermediate (MDA) and end-products of POL. Ionol shows this effect on hour 8-24 and day 6-20. Fat-soluble antioxidants act directly in the lipid bilayer of plasma and cell membranes by interacting with membrane lipophilic components.

Antioxidant activity and cytotoxicity as mediators of the neutrophil chemiluminescence inhibition by butylated hydroxytoluene

The tissue damage found in some inflammatory and autoimmune diseases has been shown to be mediated by an increased activation of neutrophil effector functions. In this study, we investigated the inhibitory effect of the phenolic compound butylated hydroxytoluene (BHT) on reactive oxygen species (ROS) generation by opsonized zymosan-stimulated neutrophils, assessed by luminol- and lucigenin-enhanced chemiluminescence (CL-lum and CL-luc, respectively), and some aspects of its mechanism of action. BHT showed concentration-dependent: (a) inhibitory effect on CL-lum and CL-luc; (b) cytotoxic effect, expressed by increased lactate dehydrogenase leakage by the cells; (c) interaction with neutrophil membranes; (d) ROS scavenger activity. These biological effects were observed in the same range of concentrations (0-5 x 10(-5) mol/l). Taken together, the results suggest that inhibition of neutrophil chemiluminescence by BHT was a result of multiple mechanisms, especially a cytotoxic effect probably mediated by BHT interaction with neutrophils membranes, and the ROS scavenging effect.

Bromophenols from the marine red alga Polysiphonia urceolata with DPPH radical scavenging activity

Three new (1-3) and three known (4-6) bromophenols were isolated and identified from the marine red alga Polysiphonia urceolata. On the basis of extensive analysis of spectroscopic data, the structures of these compounds were determined to be 7-bromo-9,10-dihydrophenanthrene-2,3,5,6-tetraol (1), 4,7-dibromo-9,10-dihydrophenanthrene-2,3,5,6-tetraol (2), 1,8-dibromo-5,7-dihydrodibenzo[ c,e]oxepine-2,3,9,10-tetraol (3), urceolatol (4), 3-bromo-4,5-dihydroxybenzaldehyde (5), and 3,5-dibromo-4-hydroxybenzaldehyde (6). Each of the isolated compounds was evaluated for alpha,alpha-diphenyl-beta-picrylhydrazyl (DPPH) radical scavenging activity, and all were found to be potent, with IC50 values ranging from 6.1 to 35.8 microM, compared to the positive control, butylated hydroxytoluene (BHT), with an IC50 of 83.8 microM.

Copper-induced peroxidation of phosphatidylserine-containing liposomes is inhibited by nanomolar concentrations of specific antioxidants

Copper-induced peroxidation of liposomal palmitoyllinoleoyl-phosphatidylcholine (PLPC) is inhibited by alpha-tocopherol at micromolar concentrations. In our previous study we found that when the liposomes contain phosphatidylserine (PS), nanomolar concentrations of Toc were sufficient to inhibit peroxidation. In an attempt to gain understanding of the origin of this extreme antioxidative potency, we tested the antioxidative potency of 36 additional antioxidants and the dependence of their potency on the presence of PS in the liposomes. The results of these studies reveal that only 11 of the tested antioxidants possess similar antioxidative potency to that of Toc. These include trolox, butylated hydroxytoluene (BHT), curcumin, nordihydroguaiaretic acid (NDGA), diethylstilbestrol (DES), 2 of the 13 tested flavonoids (luteolin and 7,3',4'-trihydroxyflavone; T-414), alpha-naphthol, 1,5-, 1,6- and 1,7-dihydroxynaphthalenes (DHNs). Propyl gallate (PG), methyl syringate, rosmarinic acid, resveratrol, other flavonoids, as well as beta-naphthol, 1,2-, 1,3-, 1,4-, 2,3-, 2,6-, and 2,7-DHNs were either moderately antioxidative or pro-oxidative. For liposomes made of PLPC (250 microM) and PS (25 microM) the "lag" preceding copper-induced peroxidation (5 microM copper) was doubled upon addition of 30-130nM of the "super-active" antioxidants. We propose that the mechanism responsible for the extreme antioxidative potency against copper-induced peroxidation in PS-containing liposomes involves replenishment of the antioxidant in a ternary PS-copper-antioxidant complex. Based on structure-activity relationship of the 37 tested antioxidants, the "super-antioxidative potency" is attributed to the recycling of relatively stable semiquinone or semiquinone-like radicals.