Antioxidant Ionol Research Articles

Modification of Cotton Cellulose with Sterically Hindered Phenolic Fragments

Samples of powder cotton cellulose modified by sterically hindered phenol fragments, whose composition and structure were established using methods of elemental analysis, IR and NMR 1H spectroscopy, were obtained. Antiradical activity of the obtained samples of modified cellulose was determined in their reactions with a stable radical—2,2-diphenyl-1-picrylhydrazyl. It was established that modification of cellulose by sterically hindered phenol fragments leads to sharp increment of its antiradical activity. Hydrazide derivative of cellulose shows antiradical activity comparable with that of antioxidant Ionol (2,6-di-tret-butyl-4-methylphenol).

SYNTHESIS AND ANTIRADICAL ACTIVITY OF HINDERED PHENOLIC DERIVATIVES OF FLAX CELLULOSE

The modification of powdered ultradisperse cellulose by hindered phenol fragments was carried out. The modification was carried out by reacting cellulose tosylate with 3-(3',5'-ditert-butyl-4'-hydroxyphenyl) propionic acid hydrazide and 3,5-ditert-butyl-4-hydroxybenzyl dimethylamine in DMF at 100 ○C for 16–30 hours. Samples of modified cellulose were characterized by spectroscopy IR and 1H NMR. From the of elemental analysis data, the degree of substitution of cellulose derivatives by hindered phenol units was calculated. The antiradical activity of the obtained samples in their reactions with a stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) was determined. The reactions of modified cellulose with DPPH were carried out under the pseudo first-order conditions with respect to the radical. From the values of the effective constants, the second-order rate constants were calculated. It was established that the modification of cellulose by hindered phenol fragments leads to a sharp increase in its antiradical activity, which depends on the degree of substitution of the sample and the method of substitution. The difference in the activity of hydrazide and benzyl derivatives of cellulose may indicate their different spatial structure, resulting in different availability of phenol fragments. The antiradical activity of the hydrazide derivative of cellulose exceeds that of the antioxidant Ionol (2,6-ditert-butyl-4-methylphenol).

Butylated Hydroxytoluene (BHT) Inhibits PIN1 Exocytosis From BFA Compartments in Arabidopsis Roots.

The activity of polarly localized PIN-FORMED (PIN) auxin efflux carriers contributes to the formation of auxin gradients which guide plant growth, development, and tropic responses. Both the localization and abundance of PIN proteins in the plasma membrane depend on the regulation of PIN trafficking through endocytosis and exocytosis and are influenced by many external and internal stimuli, such as reactive oxygen species, auxin transport inhibitors, flavonoids and plant hormones. Here, we investigated the regulation of endosomal PIN cycling by using a Brefeldin A (BFA) assay to study the effect of a phenolic antioxidant ionol, butylated hydroxytoluene (BHT), on the endocytosis and exocytosis of PIN1 and PIN2. BHT is one of the most widely used antioxidants in the food and feed industries, and as such is commonly released into the environment; however, the effect of BHT on plants remains poorly characterized. Preincubation of Arabidopsis seedlings with BHT before BFA treatment strongly enhanced the internalization of PIN1 into BFA compartments. After the simultaneous application of BHT and NAA, the NAA effect dominated PIN internalization suggesting the BHT effect occurred downstream to that of NAA. Washing seedlings with BHT after BFA treatment prevented the release of PIN1 from BFA compartments back to the plasma membrane, indicating that BHT application inhibited PIN1 exocytosis. Overall rates of PIN2 internalization were less pronounced than those of PIN1 in seedlings pre-incubated with BHT before BFA treatment, and PIN2 exocytosis was not inhibited by BHT, indicating a specific activity of BHT on PIN1 exocytosis. Comparison of BHT activity with other potential stimuli of PIN1 and PIN2 trafficking [e.g., H2O2 (ROS), salt stress, reduced glutathione (GSH), dithiothreitol (DTT), and flavonoids] showed that BHT has a new activity distinct from the activities of other regulators of PIN trafficking. The findings support BHT as a potentially interesting pharmacological tool for dissecting PIN trafficking and auxin transport.

Improving the quality of liquid insulation of oil-filled electrical equipment by introducing new additives

Stable and reliable operation of oil-filled electrical equipment at power facilities depends largely on the quality of liquid insulation — transformer oil, which is influenced by environmental and operational factors, as a result of which it is flooded, aging with precipitation and oxidation products, which leads to short circuits and breakdowns. About 85% of transformer failures are due to a violation of the insulation system. To increase the service life of transformer oil, it is traditionally added an antioxidant additive ionol, the drawback of which is its high sensitivity to organosulfur compounds. Improving the quality of transformer oil is possible due to a more effective antioxidant additive. Previous studies have shown the ambiguous effect of organosulfur compounds on the performance of transformer oil. In this regard, as well as taking into account an increase in the production and processing of sulfur and sour crude oils, the effect of individual sulfides of various structural group composition on operational indicators, such as stability indicators against oxidation of the oil fraction, saponification number, ether number, absorbed oxygen amount, and corrosion activity, was studied at operating temperatures and in an electric field of 30 kV/cm.During the study, it was found that cyclohexyldecylsulfide is the most active inhibitory additive to the oil fraction among individual organosulfur compounds. However, diphenylsulfide and diphenyldisulfide reduce stability against oxidation of the fraction, worsening its quality.It was established that when aromatic cycles in a sulfide molecule are replaced by cyclohexyl cycles, the inhibitory ability increases, increasing the quality of transformer oil and, accordingly, the reliability of operation of electrical equipment as a whole.

APPLICATION OF DOLOMITE AS A HETEROGENEOUS CATALYST OF BIODIESEL SYNTHESIS

Some of the more recent methods of obtaining biodiesel are based on heterogeneous catalysis, which has the advantage of multiple uses of a catalyst. Natural minerals, such as dolomite, opoca and serpentinites, could be promising for use in biodiesel synthesis. The purpose of this study was to optimise the reaction conditions for biodiesel synthesis from sunflower oil and methanol using dolomite as a catalyst. Optimum reaction conditions for the transesterification of sunflower oil with methanol, using dolomite calcined at the temperature of 850 °C, have been identified: the amount of the catalyst – 6%, the molar ratio of methanol to oil – 8:1, the reaction duration – 5 hours and the reaction temperature – 60 °C. The amount of Fatty Acid Methyl Esters (FAME) of the sunflower oil obtained – 97.6%. FAME is in conformity with the EN 14214:2003 standard, when 500 ppm of antioxidant Ionol and 500 ppm of depressant Infineum R-442 are added. The Cold Filter Plugging Point (CFPP) of FAME is reduced to7 °C by adding 500 ppm of Infineum R-442. This product can be used in summer in the countries that are placed in Class E, including Lithuania. It has been established that dolomite without regeneration can be used for the transesterification of sunflower oil 2 times.

Prospects for the use of direct antioxidant ionol (2,6-di-tert-butyl-4-methylphenol) for conservative treatment of cataract

Aim. To estimate the effect of ionol (2,6-di-teRt-butyl-4-methylphenol) on the dynamics of lens opacities and its free-radical status in experimental cataract. 
 Methods. Cataract was induced by a single injection of diquat dibromide solution into the vitreous body of 80 rabbits (160 eyes) at a dose of 600 nmol, 5 rabbits were included into the control intact group. Animals with induced cataract were divided into 4 groups each including 20 animals (40 eyes) who were treated with TID instillation in conjunctival cavity of: olive oil (control), «Oftan Catachrom», solution of α-tocopherol acetate, 2.2% ionol oil solution. Treatment was started on day 7. The duration of the experiment was 56 days. Dynamics of lens opacities was assessed by the following criteria: progress, stabilization and regression. In the lens homogenate the concentration of malonic dialdehyde, level of non-protein thiol (SH) groups, activity of glutathione peroxidase and glutathione transferase were determined. The results were analyzed by ANOVA, paired comparison was performed by the Newman-Keysl criterion. 
 Results. Application of ionol reduced malonic dialdehyde concentration in the lens compared to the series without treatment on days 14, 28, 42 and 56 (by 74.3, 90.0, 89.3, and 80.2%, p

The role of interspecies differences in the ratio of choline-containing phospholipid fractions of rodent erythrocytes in response of these cells to the effect of membranotropic compounds

In in vitro experiments, interspecies differences were revealed in the erythrocyte responses in varied rodent species—laboratory mice (Mus musculus L.), tundra voles (Microtus oeconomus Pall.) and bank voles (Myodes glareolus Pall.)—to the effect of chemical agents able to interact with membrane lipids and disrupt the membrane structure (detergent Triton X-100, oxidative stress inductor AAPH, antioxidant ionol or BHT, uranyl ion). It was hypothesized that these differences are due to physicochemical peculiarities of the erythrocyte membrane structure, specifically, the ratio of choline-containing fractions of phospholipids (phosphatidylcholine and sphingomyelin). The use of blood erythrocytes as an in vitro experimental model to study the mechanisms of toxicity as well as antioxidant and membrane-protective properties of compounds of different nature was shown to imply the choice of an adequate source of erythrocytes in view of considerable speciesdependent structural specificity of the lipid component of mammalian erythrocyte membranes.

Induction of heat resistance in wheat seedlings by exogenous calcium, hydrogen peroxide, and nitric oxide donor: functional interaction of signal mediators

Functional interactions of calcium ions, hydrogen peroxide, and nitric oxide as signal mediators in root cells of wheat (Triticum aestivum L.) seedlings upon induction of their heat resistance was studied with use of inhibitor-based analysis. Treatment of the seedlings with hydrogen peroxide or a combination of calcium chloride with ionophore A23187 significantly increased their content of nitric oxide, which peaked 0.5–1 h after the start of the treatment. CaCl2 or exogenous NO donor (sodium nitroprusside, SNP) transitorily increased the hydrogen peroxide level in the roots. Seedlings pretreatments with calcium chelator (EGTA), blocker of Ca2+ channels (LaCl3), inhibitor of phospholipase C (neomycin), or antagonist of cyclic adenosine-5'-diphosphatribose formation (nicotinamide) more or less prevented the rise in the nitric oxide content in roots caused by exogenous H2O2; the SNP-induced rise in hydrogen peroxide was also damped down. However, the seedlings pretreatment with antioxidants ionol or dimethylthiourea did not hinder the increase in the NO level, which was caused by exogenous Ca2+. The inhibitors of NO synthase (NG-nitro-L-arginine methyl ester, L-NAME) or nitrate reductase (sodium tungstate) did not interfere in the accumulation of H2O2 in root tissues stimulated by exogenous calcium. Calcium antagonists diminished the seedlings heat resistance increased by hydrogen peroxide or SNP. Antioxidants and inhibitors of NO synthase or nitrate reductase weakened the calcium-stimulated enhancement in the seedlings heat resistance. It was concluded that calcium may activate NO- and H2O2-generating enzymatic systems as well as participate in the transduction of signals of these mediators into genetic apparatus and in the formation of physiological reactions underlying the enhanced heat resistance.

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.

Extracellular acidification leads to mitochondrial depolarization with following free radical formation in rat brain synaptosomes

Brain ischemia is accompanied by lowering of pHo and pHi. We investigated an influence of of acidosis on free radical formation in synaptosomes. Three models were used. 1) Strong extracellular acidification down to pHo 6.0. 2) Moderate extracellular acidification down to pHo 7.0 3) Intracellular acidification induced by addition of 1 mM amiloride corresponding to pHi decrease down to 6.65. We have shown that both types of extracellular acidification, but not intracellular acidification, increase DCFDA fluorescence by calcium-independent way that reflects free radical formation. These three treatments induce the rise of the dihydroethidium fluorescence that reports synthesis of superoxide anion. However, the impact of low pHi on superoxide anion synthesis was less than induced by moderate extracellular acidification. Mitochondrial uncoupler CCCP did not inhibit an increase of fluorescence of both dyes at pHo 6.0. In contrast, superoxide anion synthesis at pHo 7.0 was almost completely eliminated by CCCP. Furthermore, using fluorescent dyes JC-1 and rhodamine-123, we confirmed that decrease of pHo leads to mitochondria depolarization. Low pHi was not effective. Iron chelator deferoxamine and antioxidant ionol are inhibits pH-induced increase of DCFDA fluorescence, but does not influenced mitochondria depolarization. We are failed to found sodium influx monitored by fluorescent dye Sodium Green in case of low pHo. Involving of plasma membrane receptor which is distinct from acid-sensitive ion channels (ASIC) and electron transport chain of mitochondria for moderate acidification can be suggested. Action of strong acidification seems to be mediated by release of iron from proteins. We have shown that low pHo led to oxidative stress in neuronal presynaptic endings that might underlie the long term irreversible changing in synaptic transmission.

Functional interaction between nitric oxide and hydrogen peroxide during formation of wheat seedling induced heat resistance

The involvement of nitric oxide (NO) and hydrogen peroxide (H2O2) in the formation of heat resistance induced by 1-min-long treatment with a temperature of 42°C in 3-day-old seedlings of winter soft wheat (Triticum aestivum L., cv. Elegiya) was studied. The content of NO in the roots was increased within 2 h after seedling hardening heating. The content of H2O2 was increased within 30 min after heating. This effect was neutralized when seedlings were treated with the nitric oxide scavenger PTIO (2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) and the inhibitor of NO synthase L-NAME (NG-nitro-L-arginine methyl ester). Seedling treatment with the antioxidants ionol and dimethylthiourea (DMTU) reduced the hardening-induced nitric oxide accumulation in tissues. When seedlings were treated with the NO donor sodium nitroprusside (SNP), the amount of endogenous NO and H2O2 in them increased; exogenous hydrogen peroxide affected similarly. Hardening heating and treatment with SNP and hydrogen peroxide increased seedling resistance to damaging heating, whereas NO antagonists (PTIO and L-NAME) and antioxidants (ionol and DMTU) prevented the development of seedling heat resistance after hardening heating. It is concluded that, during the induction of wheat seedling heat resistance by the hardening heating, functional interaction between NO and H2O2 as signaling messengers occurs.

Antiradical properties of essential oils and extracts from clove bud and pimento

The antiradical properties of essential oils and extracts from the clove bud (Eugenia caryophyllata Thumb.) and berries of tree (Pimenta dioica (L.) Meriff) were studied and compared with the properties of synthetic antioxidant ionol (2,6-ditret-butyl-4-hydroxytoluene, BHT) in model reactions with the stable free 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. The essential oils of clove bud and pimento had qualitatively close composition of the main components but differed by their quantitative content. In the studied samples, eugenol was the main compound with high antiradical activity. The reaction rates of essential oils and extracts with the DPPH radical were practically the same for essential oils and twice the reaction rate of BHT. The values of antiradical efficiency (AE) were also close for essential oils and were twice that for extracts and ionol. A synergetic action of components in the essential oil and extract of pimento on antiradical efficiency values was found.

Synthesis and Antiradical Properties of 4-Aryl-3,4-Dihydroquinolin-2-(1H)-Ones, Aza Analogs of Neoflavonoids

A convenient one-pot method is proposed for the synthesis of 4-aryl-3,4-dihydroquinolin-2(1H)-ones from the monoanilides of malonic acid and aromatic aldehydes. The antiradical activity of the synthesized 4-aryl-3,4-dihydroquinolin-2(1H)-ones was examined (tests on the inhibition of 2,2-di-phenyl-1-picrylhydrazyl and galvinoxyl). It was found that the highest antiradical activity is exhibited by derivatives of syringaldehyde; the activity of the other compounds is moderate or low, however in the 2,2-diphenyl-1-picrylhydrazyl inhibition test it is comparable with or higher than for the widely used antioxidant Ionol.

Determination of antioxidant depletion kinetics using ASTMD 7545 as the accelerated oxidation method

The oxidation stability of biodiesels obtained from the transesterification of sunflower and soybean refined oils was studied using a method of accelerated oxidation (under 700kPa oxygen atmosphere), the so-called PetrOXY method. The antioxidant Ionol BF 200 was used in a concentration range from 0 to 5000ppm, and the experiments were carried out with temperatures varying from 130 to 145°C. Oxidation kinetics could be described with a good precision, considering that correlation coefficients were above 0.99, obeying a first-order reaction kinetics in relation to the concentration of antioxidant for soybean biodiesel and an apparently zero-order kinetics for sunflower biodiesel (which was the result of mathematical approximations derived from a more chemically appropriated first-order kinetics). Reaction specific velocities were determined and enthalpies of activation for antioxidant oxidation were determined from Arrhenius plots. All the results indicated that, for the same inhibitor concentration, sunflower-derived biodiesel was less stable towards oxidation than the soybean one.

REDUCTIVE ABILITY OF 1,4-DIHYDROPYRIDINE DERIVATIVES IN RELATION TO IONS OF TRIVALENT IRON

3,5-Dicarbonyl derivatives of 2,6-dimethyl-1,4-dihydropyridine (1,4-DHP) can reduce Fe3+ to Fe2+ depending on the nature of the substituents at position 4 and in the 3,5-ester group. This ability is less pronounced for the 1,4-DHP derivatives investigated than for ascorbic acid, but among derivatives possessing antioxidant activity it is less than that of the known antioxidants ionol (BOT) and trolox. Authors: D. Tirzite, G. Tirzitis, and D. Antipova. English Translation in Chemistry of Heterocyclic Compounds , 1999, 35 (5), pp 592-594 http://link.springer.com/article/10.1007/BF02324644

The antiradical activity of plant extracts and their health-improving and prophylactic combinations with a phosholipid complex

Using the chemiluminescence method, the effective concentration of antioxidants (AO) and their antiradical activity (ARA) have been measured for 13 plant extracts. All extracts demonstrated higher ARA than that of the synthetic antioxidant ionol. The highest ARA was found in extracts from Larix dahurica, Hypericum perforatum, Potentilla fruticosa, Aronia melanocarpa, and Rhaponticum carthamoides. Synergistic action was found for combinations of extracts from Aronia + Rhaponticum, Larix + Hibiscus, and Schizandra + Aronia; the synergistic effect β was 38, 33, and 22%, respectively. This effect may be attributed to compounds present in these extracts. Phospholipids (the phospholipid complex Lipoid S40) lacking any antioxidant effect alone, showed a potent synergistic effect in combination with the Aronia extract (β = 60%) and the Silybum extract (β = 41%). Combinations of plant extracts with the phospholipids complex potentiated their inhibitory activity by increasing the induction period. Clinical trials have demonstrated, the combinations used may be recommended as an additional component in the complex therapeutic treatment of such chronic diseases as cardiovascular and hepatobiliary and also as an individual prophylactic agent.

Antiradical activity of morpholine- and piperazine-functionalized triphenylantimony(V) catecholates

The antiradical activity of the functionalized triphenylantimony(V) catecholates Ph3Sb[4-O(CH2CH2)2N-3,6-DBCat] (I), Ph3Sb[4,5-Piperaz-3,6-DBCat] (II), and Ph3Sb[4-PhN(CH2CH2)2N-3,6-DBCat] (III) (where [4-O(CH2CH2)2N-3,6-DBCat]2−, [4,5-Piperaz-3,6-DBCat]2−, and [4-PhN(CH2CH2)2N-3,6-DBCat]2− are the dianionic ligands 3,6-di-tert-butyl-4-(morpholin-1-yl)-, 3,6-di-tert-butyl-4,5-(piperazine-1,4-diyl)-, and 3,6-di-tert-butyl-4-(4-phenylpiperazin-1-yl)catecholates, respectively) was studied in reactions with the diphenylpicrylhydrazyl radical during autooxidation of unsaturated fatty (oleic and linoleic) acids with lipid peroxidation of Russian sturgeon (Acipenser gueldenstaedti B.) sperm and human blood erythrocytes in vitro as examples. The EC50 and n DPPH values obtained indicate the high antiradical activity of complexes II and III in the reactions with the stable radical. On the whole, complexes I–III inhibit the lipid peroxidation in both model (oxidation of unsaturated fatty acids) and in vitro experiments. The inhibiting effects of the complexes are comparable with and even, in some cases, higher than those of the known antioxidant ionol.

Определение антиоксидантных свойств активаторов митохондриального АТФ-зависимого калиевого канала с помощью флуоресцентного индикатора Amplex Red

The effect of adaptogens-antihypoxants that participate in the activation of mitochondrial ATP-dependent potassium channels (mitoK(ATP)) at the oxidation of the Amplex Red (AR) fluorescent indicator in a peroxidase system was tested. It was shown that Extralife, Hypoxen, taurine, and synthetic antioxidant ionol can be arranged in the following row, according to the fluorescence inhibition activity: Extralife > Hypoxen > > ionol > taurine; their effect was shown to be concentration-dependent. The calculated K(i) value of fluorescence indicators demonstrate fast and slow phases of inhibition of the AR oxidation by Extralife and Hypoxen. The fast phase occurs in the presence of microdoses (0.05-3 microg/mL) of adaptogens and is related to the competition for H2O2, which is in agreement with our previous data on the mitoK(ATP) activation by doses of adaptogens related to the H2O2 consumption. The slow phase is characteristic of high adaptogen and ionol concentrations and is related to the competition for phenoxyl radicals of resorufin formed during AR oxidation. The obtained results allow one to suggest the application of a highly sensitive model peroxidase system with AR for the preliminary testing of compounds activating mitoK(ATP) channels.

Антирадикальные свойства эфирных масел орегано, тимьяна и чабера

In model reactions with the stable free 2,2-diphenyl-1-picrylhydrazyl radical, the antiradical properties of essential oils of thyme (Thymus vulgare), oregano (Origanum vulgare), and savory (Satureja hortensis) that are similar in the qualitative composition, but differ in the quantitative content of the main components, were studied and compared with the properties of synthetic antioxidant ionol. The reaction rates of components of essential oils with the radical were almost identical for all essential oils and were twice the reaction rate of ionol. The antiradical efficiency values were close to each other for all essential oils and by an order of magnitude smaller than for ionol.

Induction of heat resistance of wheat coleoptiles by salicylic and succinic acids: Connection of the effect with the generation and neutralization of reactive oxygen species

The influence of salicylic (SaA) and succinic (SuA) acids on the generation of active oxygen forms (AOFs) and the heat resistance of wheat (Triticum aestivum L.) coleoptiles has been studied. The treatment of coleoptiles with 10 microM SaA or SuA results in the accumulation of hydrogen peroxide and enhanced formation of a superoxide anion radical. This effect is partially suppressed by both alpha-naphthol (the NADPH oxidase inhibitor) and salicylhydroxamic acid (peroxidase inhibitor). SaA and SuA cause an increase in the activity of antioxidant enzymes, such as superoxide dismutase, catalase, and soluble peroxidase, and improve the heat resistance ofcoleoptiles. Antioxidant ionol and compounds, which inhibit the NADPH oxidase and peroxidase, significantly reduce the positive influence of SaA and SuA on the heat resistance of wheat coleoptiles. AOFs are considered to be intermediates for heat resistance induction in coleoptiles, treated with SaA and SuA; enhanced AOF generation can be caused by an increased activity of the NADPH oxidase and peroxidase.