Search For New Antioxidants Research Articles

Antimicrobial and Antioxidant Activity Screening of Mushrooms Growing in the Leningrad Region

Introduction. The emergence of new strains of microorganisms that are multidrug resistant (MDR) in relation to the antimicrobial drugs used is one of the pressing problems of modern medicine. To prevent an increase in MDR-related deaths, the search for new antibiotics and their introduction into medical practice must be continuously ongoing. Infectious diseases are also accompanied by cell damage and the development of free radical oxidation processes, therefore the search for new antioxidants is also an important task. Considering the powerful biosynthetic potential of basidiomycetes, this group of fungi has every prospect of becoming a new source of biologically active substances in general, as well as antibiotics and antioxidants in particular. Cap mushrooms, represented mainly by basidiomycetes, number about 14,000 species and are an accessible source of raw materials for the search for promising antimicrobial compounds and antioxidants.Aim. Study of the antioxidant and antimicrobial activity of total extracts obtained from cap mushrooms against Escherichia coli, Staphylococcus aureus and Candida albicans and assessment of the suitability of cap mushrooms as a natural source of substances with antimicrobial and antioxidant activity.Materials and methods. The antifungal and antibacterial activity of the extracts was determined by the micromethod of two-fold serial dilutions in a liquid nutrient medium in 96-well plates in duplicate. The study of this type of biological activity was carried out against reference (type) strains Staphylococcus aureus ATCC 6538-P, Escherichia coli ATCC 25922, Candida albicans NCTC 885-653. To study antioxidant activity using DPPH, we used alcoholic extracts from the fruiting bodies of mushrooms obtained by maceration with 96 % ethanol at a ratio of raw materials to extractant of 1 to 8 for 24 hours, an aqueous solution of ascorbic acid (vitamin C) and an ethanol solution of Trolox.Result and discussion. In relation to S. aureus, a representative of gram-positive flora, the studied extracts of cap mushrooms showed low activity, on average about 2500 or 5000 μg/ml. In relation to E. coli, a representative of gram-negative flora, 8 % of the studied cap mushroom extracts showed an average activity of about 1250 μg/ml. The largest number of cap mushroom extracts – 19% of all studied species – showed activity against the yeast micromycete C. albicans. The highest activity against C. albicans was observed in extracts of the mushrooms Cantharellula umbonata with an MIC of 625 μg/ml, Cortinarius olivaceofuscus with an MIC of 625 μg/ml, and Hypomyces chrysospermus with an MIC of 312 μg/ml. During screening of antioxidant activity, the studied extracts were divided into three groups: with high (more than 50 % PPR), medium (from 15 to 50 % PPR) and low (less than 15 %) antioxidant activity. It was shown that the sum of phenolic compounds significantly correlates with the level of antioxidant activity in all three groups, but in the groups with medium and low antioxidant activity there are also other non-phenolic groups of compounds that make a significant contribution to the total antioxidant activity.Conclusion. Cap mushrooms are a promising source of biologically active substances with antifungal and antioxidant activity.

Novel iodoquinazolinones bearing sulfonamide moiety as potential antioxidants and neuroprotectors

In a search for new antioxidants, a set of new iodoquinazolinone derivatives bearing benzenesulfonamide moiety and variable acetamide pharmacophores 5–17 were designed and synthesized. The structures of the synthesized compounds were confirmed based on spectral data. Compounds 5–17 were screened using in vitro assay for their antioxidant potential and acetylcholinesterase (AChE) inhibitory activity. The 2-(6-iodo-4-oxo-3-(4-sulfamoylphenyl)-3,4-dihydroquinazolin-2-ylthio)-N-(pyrazin-2-yl) acetamide 14 was the most active scaffold with potent AChE inhibitory activity. Compound 14 showed relative safety with a median lethal dose of 300 mg/kg (LD50 = 300 mg/kg), in an acute toxicity study. The possible antioxidant and neuroprotective activities of 14 were evaluated in irradiated mice. Compound 14 possessed in vivo AChE inhibitory activity and was able to modify the brain neurotransmitters. It was able to cause mitigation of gamma radiation-induced oxidative stress verified by the decline in Myeloperoxidase (MPO) and increase of glutathione (GSH) levels. Also, 14 restored the alterations in behavioral tests. Molecular docking of 14 was performed inside MPO and AChE active sites and showed the same binding interactions as that of the co-crystallized ligands considering the binding possibilities and energy scores. These findings would support that 14 could be considered a promising antioxidant with a neuromodulatory effect.

Study of Antioxidant Activity and Quantum-chemical Calculations of 2-aminopyrroles

Introduction. Modern therapy defines oxidative stress as one of the key links in the pathogenesis of different diseases, which makes the search for new low molecular weight antioxidants actual [1]. The widely used methods are imperfect, since they reflects reactivity of the sample under artificial conditions [2–4]. The proposed technique of using the "Ecolum" biosensor makes it possible to preserve the advantages of in vitro methods and improve the accuracy of determination through the use of biological reactions of cells [5, 6].Aim. Studying of the antiradical and antioxidant activity of 2-aminopyrroles, using in vitro methods and quantum-chemical calculations. Materials and methods. Earlier, derivatives of 2-aminopyrroles were obtained. Antiradical activity of the compounds was studied using the DPPH test (2,2-diphenyl-1-picrylhydrazyl). Antioxidant activity was evaluated on the model of oxidative stress using the «Ecolum» biosensor. The calculation data of the indices of reactivity in the approximation of the gas phase were obtained using quantum-chemical methods.Results and discussion. The antioxidant activity test indicated a higher antioxidant potential of 2a, compared to 2b. Antiradical activity test revealed a greater antiradical potential of 2b. Quantum-chemical calculations showed that 2b is characterized by a higher ionization potential, which may indicate its greater resistance to oxidation compared to 2a.Conclusion. The study of the antiradical and antioxidant activity of 2-aminopyrroles showed the importance of developing a methodology for the search for new antioxidants, because of antiradical activity test deviations, compared to living cell reactions.

The use of sweet potatoes in the technology of cake dough products

The article highlights the research aimed at proving the prospects of using valuable local raw materials – sweet potatoes to increase the nutritional and biological value, as well as reducing the caloric content of flour products from cake dough. The range of flour confectionery products and the peculiarity of manufacturing technology are analyzed. Cake flour products occupy a significant place in the general structure in terms of production, although the analysis of their physical and chemical composition gives grounds to claim that they do not always have a high degree of nutritional and biological value, balanced chemical composition. This is due to the high proportion of carbohydrates, fats and low content of proteins, vitamins and other biologically active compounds. In addition to nutritional value, the shelf life of products is an important factor. Cake products belong to the fat-containing flour confectionery products, and accordingly they are subjected to oxidative treatment, which encourages the search for new antioxidants of natural origin. The aim of the work is to improve the technology of cake batter with the use of sweet potato puree and to study the influence of additives of local plant raw materials on the structural-mechanical and organoleptic characteristics of finished products. The local raw material of sweet potatoes, which is characterized by a valuable chemical composition as a source of vitamins, micro- and macroelements of pectin and dyes, was chosen as an improver. The main indicators of the quality of sweet potato puree were determined experimentally. The influence of sweet potato puree on the organoleptic characteristics of the finished products was investigated, and it was found that the introduction of 20 % puree by weight of flour is optimal. As the concentration of the puree increases, the taste of the product deteriorates, as well as the porosity decreases and the color changes. The positive effect of sweet potato puree on physico-chemical indicators of the quality of finished products has been established. When adding puree in the amount of 20 % by weight of flour, the porosity is increased by 8 % in comparison with the control sample. The technology of obtaining a cake from sweet potato puree has been developed. The prescription composition and the basic technological scheme of their production are substantiated. It is proved that flour products with the addition of sweet potato puree in the amount of 20 % to the weight of the flour are slower to harden and retain their properties for 9 days of storage. The safety of prolonged storage has been confirmed by microbiological studies. Thus, the expediency of using sweet potato puree in the technology of cake dough products in order to reduce calories, increase the biological value, improve organoleptic characteristics. As well as the possibility of replacing artificial improvers in the structure, taste and aroma of cakes, due to the substances contained in sweet potato puree.

Synthesis and antioxidant activity of derivatives of 8Н -[1,2,4]triazolo[4,3-в][1,2,4]triazin-7-ones

Oxidative stress is usually connected with many severe diseases, such as atherosclerosis, hypertension, Alzheimer’s disease etc. Therefore, the search for new antioxidants is a very important pharmacological task. The aim of the study – to synthesize new derivatives of 8-(41-hydroxy-3R-benzylidenamino)-6-tertbutyl-8Н-[1,2,4]triazolo[4,3-b][1,2,4]triazine-7-ones and to evaluate their antioxidant properties in screening test in vitro as compared with ionol and ascorbic acid. By interaction of equimolar amounts of 8-amino-6-tert-butyl-8H-[1,2,4]triazolo[4,3-b][1,2,4]triazin7-one with the corresponding aromatic and heterocyclic aldehydes in ethanol, a series of Schiff bases with the key fragment 8H-[1,2,4]triazolo[4,3-b][1,2,4]triazin-7-one were synthesized. The structure and purity of all the substances obtained were confirmed by 1H NMR spectroscopy. Screening of compound’s antioxidant activity (AOA) was studied in vitro by their ability to inhibit lipoperoxide formation, induced by FeSO4 in yolk lipoproteins emulsion. It is shown, that, depending on the structure, the test substances exhibit both antioxidant and prooxidant properties. The regularities of the chemical structure – pharmacological action are established. It is shown that the introduction of electron-withdrawing substituents (F, Cl, Br and COOMe) into the benzene ring leads to a decrease in the antioxidant properties as to the base molecule 6-tert-butyl-8(benzylideneamino)-8Н-[1,2,4]triazolo[4,3-b][1,2,4]triazin-7-оne 8 а without substitutes. The most active were derivatives of 8-(benzylideneamino)-6-~{tert}-butyl-[1,2,4]triazolo[4,3-b][1,2,4]triazin7-ones, which had a hydroxyl group and an additional oxyalkyl fragment in the third position of the benzene ring (8 l, 8 o). The data obtained substantiate the feasibility of further studying the most active derivatives of 6-tertbutyl-8-(benzylideneamino)-8Н-[1,2,4]triazolo[4,3-b][1,2,4]triazin-7-оnes as potential antioxidant agents.

Antioxidant Properties of Fullerene Derivatives Depend on Their Chemical Structure: A Study of Two Fullerene Derivatives on HELFs.

Oxidative stress is a major issue in a wide number of pathologies (neurodegenerative, cardiovascular, immune diseases, and cancer). Because of this, the search for new antioxidants is an important issue. One of the potential antioxidants that has been enthusiastically discussed in the past twenty years is fullerene and its derivatives. Although in aqueous solutions fullerene derivatives have shown to be antioxidants, their properties in this regard within the cells are controversially discussed. We have studied two different water-soluble fullerene C60 and C70 derivatives on human embryonic lung fibroblasts at a wide range of concentrations. Both of them cause a decrease in cellular ROS at short times of incubation (1 hour). Their prolonged action, however, is fundamentally different: derivative GI-761 causes secondary oxidative stress whereas derivative VI-419-P3K keeps ROS levels under control values. To gain a better understanding of this effect, we assessed factors that could play a role in the response of cells to fullerene derivatives. Increased ROS production occurred due to NOX4 upregulation by GI-761. Derivative VI-419-P3K activated the transcription of antioxidant master regulator NRF2 and caused its translocation to the nucleus. This data suggests that the antioxidant effect of fullerene derivatives depends on their chemical structure.

Discovering Antioxidant Molecules in the Archaea Domain: Peroxiredoxin Bcp1 from Sulfolobus solfataricus Protects H9c2 Cardiomyoblasts from Oxidative Stress.

Peroxiredoxins (Prxs) are ubiquitous thiol peroxidases that are involved in the reduction of peroxides. It has been reported that prokaryotic Prxs generally show greater structural robustness than their eukaryotic counterparts, making them less prone to inactivation by overoxidation. This difference has inspired the search for new antioxidants from prokaryotic sources that can be used as possible therapeutic biodrugs. Bacterioferritin comigratory proteins (Bcps) of the hyperthermophilic archaeon Sulfolobus solfataricus that belong to the Prx family have recently been characterized. One of these proteins, Bcp1, was chosen to determine its antioxidant effects in H9c2 rat cardiomyoblast cells. Bcp1 activity was measured in vitro under physiological temperature and pH conditions that are typical of mammalian cells; the yeast thioredoxin reductase (yTrxR)/thioredoxin (yTrx) reducing system was used to evaluate enzyme activity. A TAT-Bcp1 fusion protein was constructed to allow its internalization and verify the effect of Bcp1 on H9c2 rat cardiomyoblasts subjected to oxidative stress. The results reveal that TAT-Bcp1 is not cytotoxic and inhibits H2O2-induced apoptosis in H9c2 cells by reducing the H2O2 content inside these cells.

Synthesis and Biological Activity of 3-(2-Oxoalkylidene)-3,4-Dihydro-2H-1,4-Benzoxazines

A simple and convenient method for the synthesis of biologically active 3-(2-oxoalkylidene)-3,4-dihydro2H-1,4-benzoxazin-2-ones was proposed. The structures of the synthesized compounds were established using NMR and IR spectroscopy and mass spectrometry. It was established that the synthesized compounds possessed antioxidant, antiradical, and strong antihypoxant activity and exhibited low acute toxicity, which allowed the search for new antioxidants and antihypoxants among benzoxazines to continue.

Синтез и биологическая активность 3-(2-оксоалкилиден)-3,4-дигидро-2<I>H</I>-1,4-бензоксазинов

Предложен простой и удобный способ синтеза биологически активных 3-(2-оксоалкилиден)-3,4-дигидро-2H-1,4-бензоксазинов. На основании данных ИК, ЯМР 1H спектроскопии и масс-спектрометрии установлено строение синтезированных соединений. Доказано, что исследуемые соединения проявляют антиоксидантную, антирадикальную, высокую антигипоксическую активность, проявляют низкую острую токсичность, что позволяет в дальнейшем вести поиск антиоксидантов и антигипоксантов в ряду бензоксазинов.

ANTIOXIDANT AND TOXICITY ACTIVITY IN VITRO OF TWELVE SAFROLE DERIVATIVES

ABSTRACT The aim of this study was to determine the influence of substituents in aromatic ring and the side chain of safrole on the antioxidant capacity and toxicity of twelve synthetic derivatives of safrole ( S1-S12 ). Each compound was analyzed by two antioxidant methods: DPPH and bleaching of β-carotene (DBC). Among the derivates of safrol assayed, S5 , S6 , S9 , S10 and S11 showed the strongest antioxidant capacity: DPPH method, first order specific rate constant (0.0152, 0.0211, 0.0432, 0.0317 and 0.0072) and DBC (22.41 + 0.13%, 10.71 + 0.05 %, 9.12 + 0.89 %, 30.97 + 0.92 % and 19.08 + 0.31 %), respectively. The toxicity of the active compounds was evaluated by means of two techniques, Artemia salina, LD 50 (4466 ± 1057 ppm, 630 ± 108 ppm, 1513 ± 797 ppm, 1585 ± 317 ppm, 1259 ± 242 ppm) and red cells, Haemolysis (1.58 + 0.98%, 4.02 + 2.03%, 8.42 + 1.38%, 2.59+ 2.31%, 2.92 + 0.52%), to provide preliminary information that can be used as a basis for further studies to contribute to the search for new antioxidants.

Atividades antioxidante e alelopática do extrato e frações obtidos de Rosmarinus officinalis

The species Rosmarinus officinalis L. is popularly known as rosemary, being widely used in traditional medicine. In the present study, the ethanol extract and fractions obtained from R. officinalis were evaluated for allelopathic and antioxidant activities and determined the content of phenolic compounds. The ethanol extract and fractions showed antioxidant activity in five concentrations tested. Regarding the EC50 values,the ethanol extract and fractions showed better results than the BHT, reference compound. The EC50 values obtained for the ethanol extract and fractions could not be correlated directly with the content of phenolic compounds present in the samples. For allelopathic activity, the samples were able to stimulate and also inhibited the growth of hypocotyl and radicle observed at different concentrations (50, 100 and 200 mg/mL). For the radicle onion (Allium cepa), the best results were obtained for the ethanol extract and fractions hexane and dichloromethane, which inhibited growth at all concentrations, and the dichloromethane fraction promoted an inhibition greater than 80.0%, at a concentration of 200 mg/mL. Regarding the onion hypocotyl, the effects were heterogeneous. The results for the growth of radicle and hypocotyl of lettuce seeds (Lactuca sativa) showed that the inhibitory effect was more significant than the stimulatory, when the seeds were treated with the ethanol extract and factions. Regarding the inhibitory effect, they emphasized the dichloromethane fraction with a 100.0% inhibition, at a concentration of 200 mg/mL. Inhibition of hypocotyl was more significant than the radicle for lettuce seeds. The ethanol extract and dichloromethane fraction had an inhibitory effect, at all concentrations tested. In the search for new antioxidants and allelochemicals of natural origin, the species Rosmarinus officinalis may be a good candidate.

Comparative study of redox characteristics and antioxidant activity of porphyrins with 2,6-dialkylphenol groups

152 The oxidative stress of an organism is a result of the acceleration of lipid peroxidation (LPO) in cells and the formation of reactive oxygen species and free rad icals. This process leads to destruction of membranes, the emergence of numerous pathologies, and prema ture aging of the organism. The search for new antiox idants, as well as for methods to assess the antioxidant activity, is an important and interesting task [1]. Of particular interest are synthesis and study of properties of polyfunctional compounds with several pharma cophoric centers in the molecule, because such a com bination is able not only to enhance the known physi ological activity but also to cause the appearance of new types of physiological activity [2–4]. Ionol I (2,6 di tert butyl 4 methylphenol) is a known anti oxidant used in the manufacture of foodstuffs (food additive E321). 2,6 Diisobornyl 4 methylphenol (dibornol) IV is currently undergoing preclinical tri als as a promising drug [5]. CHEMISTRY

Vitamins and Cancer: To Take or Not Take?

Copyright: © 2012 Eskin NAM. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Oxidative stress is involved in the development of many chronic diseases including cancer. It has been defined as an imbalance between the level of pro-oxidants (reactive oxygen species, ROS) produced during normal metabolism and the organism’s endogenous antioxidant defence system. The role of various natural antioxidant defence systems to minimize oxidative damage caused by these free radicals was established using animal models in which these defence systems were knocked out [1]. This resulted in the promotion of cancer which was attributed to DNA damage by the formation of 8-hydroxy2-deoxyguanosine (8OHdg). Consequently, a concerted effort has been made to establish the efficacy of such traditional antioxidants as vitamins A, E and C, as well as a search for new antioxidants to minimize such damage. Over 200 epidemiological studies strongly associated low consumption of fruits and vegetables with the incidence of cancer suggesting that antioxidants might be a solution [2]. Consequently, should cancer patients be encouraged to take multivitamin supplements as part of their therapy?

Structural and electronic properties of Z isomers of (4α→6´´,2α→O→1´´)-phenylflavans substituted with R = H, OH and OCH3 calculated in aqueous solution with PCM solvation model

In the search for new antioxidants, flavan structures called our attention, as substructures of many important natural compounds, including catechins (flavan-3-ols), simple and dimeric proanthocyanidins, and condensed tannins. In this work the conformational space of the Z-isomers of (4α→6´´, 2α→O→1´´)-phenylflavans substituted with R = H, OH and OCH(3) was scanned in aqueous solution, simulating the solvent by the polarizable continuum model (PCM). Geometry optimizations were performed at B3LYP/6-31 G level. Electronic distributions were analyzed at a better calculation level, thus improving the basis set (6-311++G). A topological study based on Bader´s theory (atoms in molecules) and natural bond orbital (NBO) framework was performed. Furthermore, molecular electrostatic potential maps (MEPs) were obtained and thoroughly analyzed. The stereochemistry was discussed, and the effect of the solvent was addressed. Moreover, intrinsic properties were identified, focusing on factors that may be related to their antioxidant properties. Hyperconjugative and inductive effects were described. The coordinated NBO/AIM analysis allowed us to rationalize the changes of MEPs in a polar solvent. To investigate the molecular and structural properties of these compounds in biological media, the polarizabilities and dipolar moments were predicted which were further used to enlighten stability and reactivity properties. All conformers were taken into account. Relevant stereoelectronic aspects were described for understanding the stabilization and antioxidant function of these structures.

Antioxidant, antimicrobial, and tyrosinase inhibition activities of acetone extract of Ascophyllum nodosum

AbstractThe search for new antioxidants of natural origin derived from plants and seaweeds is still very important at present. In our study, the acetone extract of A. nodosum was investigated for its potential use as a natural antioxidant, natural feed additive with antibacterial activity and as a tyrosinase inhibitor. This study could be useful in the context of improved utilization of the A. nodosum extract in the food and cosmetics industry, being not only economically advantageous but also environmentally friendly. Extracts showed antioxidant activity with application of different methodologies: 1,1-diphenyl-2-picrilhydracil DPPH· radicals scavenging (39 %, 4 mg of freeze-dried sample), β-carotene-linoleic acid antioxidant assay (11 %, 4 mg of freeze-dried sample), O2· radicals scavenging activity (IC50 0.43 mg mL−1), OH· radicals scavenging activity (IC50 1.55 mg mL−1), and iron chelation ability (IC50 0.56 mg mL−1). The extract showed considerable antibacterial activity being more effective against gram-positive bacteria (Micrococcus luteus, Staphylococcus aureus) than against gram-negative bacteria (Escherichia coli, Enterococcus aerogenes). Results of tyrosinase assay for the acetone extract of Ascophyllum nodosum presented 65.6 % inhibition of tyrosinase activity at the IC50 value of 0.1 mg mL−1. The outcomes of our study support potential utilization of this brown seaweed as a source of natural antioxidants. Antioxidant activity of the studied seaweed can be apparently explained by the free radicals scavenging activity, particularly related to the mechanisms of O2−· radicals scavenging activity, OH· radicals inactivation, and iron chelation ability.

Kinetic Analysis of Permeation of Mitochondria-Targeted Antioxidants Across Bilayer Lipid Membranes

Mitochondria-targeted antioxidants consisting of a quinone part conjugated with a lipophilic cation via a hydrocarbon linker were previously shown to prevent oxidative damage to mitochondria in vitro and in vivo. In the present work, we studied the permeation of a series of compounds of this type across a planar bilayer phospholipid membrane. For this purpose, relaxation of the electrical current after a voltage jump was measured. With respect to the characteristic time of the relaxation process reflecting the permeation rate, hydrophobic cations can be ranked in the following series: 10(plastoquinonyl) decylrhodamine 19 (SkQR1) > 10-(6'-plastoquinonyl) decyltriphenylphosphonium (SkQ1) > 10-(6'-methylplastoquinonyl) decyltriphenylphosphonium (SkQ3) > 10-(6'-ubiquinonyl) decyltriphenylphosphonium (MitoQ). Thus, the permeation rate increased with (1) an increase in the size of the hydrophobic cation and (2) an increase in hydrophobicity of the quinone moiety. SkQ1 containing plastoquinone was shown to be more permeable through the membrane compared to MitoQ containing ubiquinone, which might be the reason for more pronounced beneficial action of SkQ1 in vitro and in vivo. The above approach can be recommended for the search for new antioxidants or other compounds targeted to mitochondria.

Toxicology and free radicals scavenging property of Tamra bhasma

Free radicals are implicated in various chronic diseases. There has always been a search for new antioxidants. In this paper we have investigated Tamra bhasma, a metallic ayurvedic preparation. It is a time-tested medicine in Ayurveda and is in clinical use for various ailments specifically the free radical mediated diseases. Our results show that Tamra bhasma inhibits lipid peroxidation (LPO), prevents the rate of aerial oxidation of reduced glutathione (GSH) content and induces the activity of superoxide dismutase (SOD) in rat liver homogenate in the bi-phasic manner. The drug was orally given for 7, 15 and 30 days in different doses. Best protective response was found at the dose of 0.5mg/100g body weight in albino rats, although it showed some histopathological changes at the dose of 20mg/100g body weight. The results suggest that this Ayurvedic preparation is not merely a source of copper metal, but it is a strong anti-oxidant with no detectable adverse effect in lower doses of therapeutic range.