scholarly journals Kinetic Studies of Antioxidant Properties of Ovothiol A

Antioxidants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1470
Author(s):  
Nataliya A. Osik ◽  
Ekaterina A. Zelentsova ◽  
Yuri P. Tsentalovich
Keyword(s):  
Rate Constants ◽  
Marine Invertebrates ◽  
Antioxidant Properties ◽  
Kinetic Studies ◽  
Natural Antioxidants ◽  
Sulfenic Acid ◽  
Diffusion Controlled ◽  
Sh Group ◽  
Solar Uv ◽  
High Concentrations

Ovothiol A (OSH) is one of the strongest natural antioxidants. So far, its presence was found in tissues of marine invertebrates, algae and fish. Due to very low pKa value of the SH group, under physiological conditions, this compound is almost entirely present in chemically active thiolate form and reacts with ROS and radicals significantly faster than other natural thiols. In biological systems, OSH acts in tandem with glutathione GSH, with OSH neutralizing oxidants and GSH maintaining ovothiol in the reduced state. In the present work, we report the rate constants of OSH oxidation by H2O2 and of reduction of oxidized ovothiol OSSO by GSH and we estimate the Arrhenius parameters for these rate constants. The absorption spectra of reaction intermediates, adduct OSSG and sulfenic acid OSOH, were obtained. We also found that OSH effectively quenches the triplet state of kynurenic acid with an almost diffusion-controlled rate constant. This finding indicates that OSH may serve as a good photoprotector to inhibit the deleterious effect of solar UV irradiation; this assumption explains the high concentrations of OSH in the fish lens. The unique antioxidant and photoprotecting properties of OSH open promising perspectives for its use in the treatment of human diseases.

Direct detection of methylphenylgermylene and 1,2-dimethyl-1,2-diphenyldigermene — Kinetic studies of their reactivities in solution

2006 ◽  
Vol 84 (7) ◽  
pp. 934-948 ◽  
Author(s):  
William J Leigh ◽  
Ileana G Dumbrava ◽  
Farahnaz Lollmahomed
Keyword(s):  
Acetic Acid ◽  
Rate Constants ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Direct Detection ◽  
Kinetic Studies ◽  
Laser Flash ◽  
Absolute Rate ◽  
Hydrocarbon Solvents ◽  
Diffusion Controlled

Photolysis of 1,3,4-trimethyl-1-phenylgermacyclopent-3-ene (5) in hydrocarbon solvents containing isoprene, methanol, or acetic acid affords 2,3-dimethyl-1,3-butadiene (DMB) and the expected trapping products of methyl phenylgermylene (GeMePh) in chemical yields exceeding 90%. The germylene has been detected in hexane solution by laser flash photolysis as a short-lived species (τ ~ 2 µs) exhibiting a UV-vis absorption spectrum centered at λmax = 490 nm. It decays with second-order kinetics and a rate constant close to the diffusion-controlled limit, with the concomitant growth of a second longer-lived transient (λmax = 420 nm) that is assigned to a mixture of (E)- and (Z)-1,2-dimethyl-1,2-diphenyldigermene (4). Absolute rate constants have been determined for the reactions of the germylene with primary and tertiary amines (n-BuNH2 and Et3N, respectively), acetic acid (AcOH), a terminal alkyne and alkene, isoprene, DMB, CCl4, and the group 14 hydrides Et3SiH and Bu3SnH. GeMePh is slightly more reactive than GePh2 towards all the reagents studied in this work; both are significantly less reactive than GeMe2 toward the same substrates. Absolute rate constants for the reactions of 4 have also been measured or assigned upper limits in every case and are compared to previously reported values for tetraphenyl- and tetramethyl-digermene with the same reagents.Key words: germylene, digermene, kinetics, laser flash photolysis, germirane, germirene, vinylgermirane, complex, UV–vis spectrum, insertion, addition.

Punica granatum as a Source of Natural Antioxidant and Antimicrobial Agent; a Comprehensive Review on Related Investigations

2020 ◽  
Vol 17 ◽  
Author(s):  
Atefeh Jalali ◽  
Mohammadreza Kiafar ◽  
Masih Seddigh ◽  
Mohammad M. Zarshenas
Keyword(s):  
Antioxidant Activities ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Natural Antioxidants ◽  
Punica Granatum ◽  
Antimicrobial Activities ◽  
Natural Antioxidant ◽  
Antiviral Activities ◽  
Natural Foods

Background: The consumption of natural antioxidants is increasing due to the demand and tendency to natural foods. Punica granatum L. [Punicaceae] is a fruit with various bioactive ingredients. The effectiveness of this plant has been proved against various disorders such as hyperglycemia, hyperlipidemia, blood coagulation, infections, cancer, and dentistry. Among them, there are numerous researches on antimicrobial and antioxidant properties. Subsequently, the present study aimed to compile a review of those properties to outline this herb as a possible natural antioxidant and preservative. Methods: Synchronically, keywords "Punica granatum" with antimicrobial, or antibacterial, antifungal, antiviral, antioxidant and radical scavenging were searched through "Scopus" database up to 31st September 2019. Papers focusing on agriculture, genetics, chemistry, and environmental sciences were excluded and also related papers were collected. Results: Among 201 papers focusing on related activities, 111 papers have dealt with antioxidant activities focusing based on DPPH assay, 59 with antibacterial, on both gram+ and gram- bacteria, 24 with antifungal effects, mostly on Aspergillus niger and Candida albicans, and 7 papers with antiviral activities. There were about 50 papers focusing on in-vivo antioxidant activities of this plant. Conclusion: Taken together, botanical parts of P. granatum have possessed notable radical scavenging and antimicrobial activities that with these properties, this plant can be introduced as a natural safe source of preservative and antioxidant. Accordingly, P. granatum can be applied as excipient with the aforementioned properties in the pharmaceutical and food industries.

Efficient Preconcentration of Cu2+, Zn2+ and Fe3+ with an Agarose-Schiff Base Sorbent

2007 ◽  
Vol 72 (7) ◽  
pp. 908-916 ◽  
Author(s):  
Payman Hashemi ◽  
Hatam Hassanvand ◽  
Hossain Naeimi
Keyword(s):  
Schiff Base ◽  
Metal Ions ◽  
Metal Ion ◽  
Good Accuracy ◽  
Kinetic Studies ◽  
Sample Volume ◽  
Effects Of Ph ◽  
Glass Column ◽  
High Concentrations ◽  
Ph Range

Sorption and preconcentration of Cu2+, Zn2+ and Fe3+ on a salen-type Schiff base, 2,2'- [ethane-1,2-diylbis(nitrilomethylidyne)]bis(2-methylphenol), chemically immobilized on a highly crosslinked agarose support, were studied. Kinetic studies showed higher sorption rates of Cu2+ and Fe3+ in comparison with Zn2+. Half-times (t1/2) of 31, 106 and 58 s were obtained for sorption of Cu2+, Zn2+ and Fe3+ by the sorbent, respectively. Effects of pH, eluent concentration and volume, ionic strength, buffer concentration, sample volume and interferences on the recovery of the metal ions were investigated. A 5-ml portion of 0.4 M HCl solution was sufficient for quantitative elution of the metal ions from 0.5 ml of the sorbent packed in a 6.5 mm i.d. glass column. Quantitative recoveries were obtained in a pH range 5.5-6.5 for all the analytes. The volumes to be concentrated exceeding 500 ml, ionic strengths as high as 0.5 mol l-1, and acetate buffer concentrations up to 0.3 mol l-1 for Zn2+ and 0.4 mol l-1 for Cu2+ and Fe3+ did not have any significant effect on the recoveries. The system tolerated relatively high concentrations of diverse ions. Preconcentration factors up to 100 and detection limits of 0.31, 0.16 and 1.73 μg l-1 were obtained for Cu2+, Zn2+ and Fe3+, respectively, for their determination by a flame AAS instrument. The method was successfully applied to the metal ion determinations in several river water samples with good accuracy.

scholarly journals Antioxidant Capacity and Phenolic and Sugar Profiles of Date Fruits Extracts from Six Different Algerian Cultivars as Influenced by Ripening Stages and Extraction Systems

Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 503
Author(s):  
Malika Tassoult ◽  
Djamel Edine Kati ◽  
María África Fernández-Prior ◽  
Alejandra Bermúdez-Oria ◽  
Juan Fernandez-Bolanos ◽  
...  
Keyword(s):  
Sugar Content ◽  
Antioxidant Properties ◽  
Dry Weight ◽  
Natural Antioxidants ◽  
Antioxidant Power ◽  
Fruit Extracts ◽  
Ripening Stages ◽  
Date Fruit ◽  
Ferric Reducing Antioxidant Power ◽  
First Time

The study investigated the phenols, sugar and the antioxidant capacities of date fruit extracts obtained by organic solvents and by hydrothermal treatment from six different Algerian cultivars at two ripening stages for the first time. The analyzed cultivars exhibited potent antioxidant properties (ferric reducing antioxidant power (FRAP), 1,1-Diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) scavenging capacities) and different phenols regardless of the solvents and the maturity stages. About 18 phenols were identified and quantified, mainly in the hydrothermal extracts. The earlier stages were characterized by high amounts of o-coumaric acid, cinnamic acid and luteolin, with a noticeable absence of quercetin. The tamr stage presented the highest sugar content (78.15–86.85 mg/100 mg dry weight (DW)) with an abundance of glucose. Galactose was present only in some cultivars from the kimri stage (tamjouhert). Uronic acids were mostly detected at the tamr stage (4.02–8.82 mg gallic acid equivalent/100 mg dried weight). The obtained results highlight the potential of using date fruit extracts as natural antioxidants, especially at industrial scales that tend use hydrothermal extraction.

scholarly journals Preliminary Study on Pasta Samples Characterized in Antioxidant Compounds and Their Biological Activity on Kidney Cells

Nutrients ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 1131 ◽  
Author(s):  
Federico Di Marco ◽  
Francesco Trevisani ◽  
Pamela Vignolini ◽  
Silvia Urciuoli ◽  
Andrea Salonia ◽  
...  
Keyword(s):  
Indoleacetic Acid ◽  
Antioxidant Properties ◽  
Antioxidant Compounds ◽  
Kidney Cells ◽  
Hek 293 ◽  
293 Cells ◽  
High Concentrations ◽  
Β Carotene ◽  
Egg Pasta

Pasta is one of the basic foods of the Mediterranean diet and for this reason it was chosen for this study to evaluate its antioxidant properties. Three types of pasta were selected: buckwheat, rye and egg pasta. Qualitative–quantitative characterization analyses were carried out by HPLC-DAD to identify antioxidant compounds. The data showed the presence of carotenoids such as lutein and polyphenols such as indoleacetic acid, (carotenoids from 0.08 to 0.16 mg/100 g, polyphenols from 3.7 to 7.4 mg/100 g). To assess the effect of the detected metabolites, in vitro experimentation was carried out on kidney cells models: HEK-293 and MDCK. Standards of β-carotene, indoleacetic acid and caffeic acid, hydroalcoholic and carotenoid-enriched extracts from samples of pasta were tested in presence of antioxidant agent to determine viability variations. β-carotene and indoleacetic acid standards exerted a protective effect on HEK-293 cells while no effect was detected on MDCK. The concentrations tested are likely in the range of those reached in body after the consumption of a standard pasta meal. Carotenoid-enriched extracts and hydroalcoholic extracts showed different effects, observing rescues for rye pasta hydroalcoholic extract and buckwheat pasta carotenoid-enriched extract, while egg pasta showed milder dose depending effects assuming pro-oxidant behavior at high concentrations. The preliminary results suggest behaviors to be traced back to the whole phytocomplexes respect to single molecules and need further investigations.

scholarly journals Biological Properties and Prospects for the Application of Eugenol—A Review

2021 ◽  
Vol 22 (7) ◽  
pp. 3671
Author(s):  
Magdalena Ulanowska ◽  
Beata Olas
Keyword(s):  
Body Weight ◽  
Aromatic Compound ◽  
Therapeutic Potential ◽  
Antioxidant Properties ◽  
Biological Properties ◽  
Clove Oil ◽  
Current State ◽  
Potential Component ◽  
Anti Inflammatory ◽  
High Concentrations

Eugenol is a phenolic aromatic compound obtained mainly from clove oil. Due to its known antibacterial, antiviral, antifungal, anticancer, anti-inflammatory and antioxidant properties, it has long been used in various areas, such as cosmetology, medicine, and pharmacology. However, high concentrations can be toxic. A dose of 2.5 mg/kg body weight is regarded as safe. This paper reviews the current state of knowledge regarding the activities and application of eugenol and its derivatives and recent research of these compounds. This review is based on information concerning eugenol characteristics and recent research from articles in PubMed. Eugenol remains of great interest to researchers, since its multidirectional action allows it to be a potential component of drugs and other products with therapeutic potential against a range of diseases.

scholarly journals Beneficial Role of Carica papaya Extracts and Phytochemicals on Oxidative Stress and Related Diseases: A Mini Review

Biology ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 287
Author(s):  
Yew Rong Kong ◽  
Yong Xin Jong ◽  
Manisha Balakrishnan ◽  
Zhui Ken Bok ◽  
Janice Kwan Kah Weng ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Signaling Pathways ◽  
Chronic Diseases ◽  
Carica Papaya ◽  
Antioxidant Properties ◽  
Natural Antioxidants ◽  
The Body ◽  
Health Conditions ◽  
Chemical Components ◽  
Impaired Wound Healing

Oxidative stress is a result of disruption in the balance between antioxidants and pro-oxidants in which subsequently impacting on redox signaling, causing cell and tissue damages. It leads to a range of medical conditions including inflammation, skin aging, impaired wound healing, chronic diseases and cancers but these conditions can be managed properly with the aid of antioxidants. This review features various studies to provide an overview on how Carica papaya help counteract oxidative stress via various mechanisms of action closely related to its antioxidant properties and eventually improving the management of various oxidative stress-related health conditions. Carica papaya is a topical plant species discovered to contain high amounts of natural antioxidants that can usually be found in their leaves, fruits and seeds. It contains various chemical compounds demonstrate significant antioxidant properties including caffeic acid, myricetin, rutin, quercetin, α-tocopherol, papain, benzyl isothiocyanate (BiTC), and kaempferol. Therefore, it can counteract pro-oxidants via a number of signaling pathways that either promote the expression of antioxidant enzymes or reduce ROS production. These signaling pathways activate the antioxidant defense mechanisms that protect the body against both intrinsic and extrinsic oxidative stress. To conclude, Carica papaya can be incorporated into medications or supplements to help manage the health conditions driven by oxidative stress and further studies are needed to investigate the potential of its chemical components to manage various chronic diseases.

scholarly journals Stabilization Effects of Natural Compounds and Polyhedral Oligomeric Silsesquioxane Nanoparticles on the Accelerated Degradation of Ethylene-Propylene-Diene Monomer

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4390
Author(s):  
Traian Zaharescu ◽  
Ignazio Blanco
Keyword(s):  
Antioxidant Properties ◽  
Polyhedral Oligomeric Silsesquioxane ◽  
Natural Antioxidants ◽  
Rosemary Extract ◽  
Γ Irradiation ◽  
Ethylene Propylene ◽  
Radical Intermediates ◽  
Accelerated Degradation ◽  
Evaluation Procedures ◽  
Oligomeric Silsesquioxane

In this work the analysis on the stabilization activities of some natural antioxidants (rosemary extract, capsaicin, quercetin or oleanolic acid) is presented. A similar contribution of an inorganic structure—polyhedral oligomeric silsesquioxane (POSS) nanoparticles—is also evaluated. The stabilization effects on the oxidation protection were investigated for several formulations based on ethylene-propylene-diene-terpolymer (EPDM). The samples were examined in pristine state or after γ-irradiation, when the accelerated degradation scission of polymer macromolecules followed by the mitigation of oxidation. Three evaluation procedures: chemiluminescence, FTIR spectroscopy and thermal analysis were applied for the characterization of stability efficiency. The delaying effect of oxidative aging in EPDM matrix is illustrated by the values of activation energy, which are correlated with the type and concentration of embedded compounds. The durability of studied EPDM formulations is discussed for the assessment of material life. The improved behavior of structured hybrids useful for the optimization application regimes is essentially based on the antioxidant properties of polyphenolic components in the cases of natural antioxidants or on the penetration of free radical intermediates into the free volumes of POSS.

Phytochemical and antioxidant properties of Algerian Medicago Sativa L. Water, Ethenol and Chloroform extract

2019 ◽  
Vol 9 (3) ◽  
pp. 80-86
Author(s):  
Hanane Megdad ◽  
Samuel Chiomokhare ◽  
Ahmed M’Hamedi ◽  
Paul L Chazot
Keyword(s):  
Antioxidant Activity ◽  
Medicago Sativa ◽  
Phenolic Content ◽  
Antioxidant Properties ◽  
Ethanol Extract ◽  
Natural Antioxidants ◽  
Chloroform Extract ◽  
Total Phenolic ◽  
Medicago Sativa L ◽  
Ethanol Extracts

Plant natural products have a long history of being a rich source of neuroactive drugs.The total phenolic and flavonoid content, and antioxidant activity of ethanol, chloroform and aqueous extracts of AlgerianMedicagoSativaL, leaves were measured to discover new potential sources of Algerian natural antioxidants and neuroactives. All extracts were non-neurotoxic up to 1 mg/ ml for 24 h exposure. The total phenolcontent of M.Sativa extracts ranged between 38 and 69 mg GAE per g extracts. All of the extracts displayed antioxidant capacityassessed by two methods, but at different levels depending on the concentration and the extraction solvent used. The overall antioxidant potency was in the order water > chloroform> ethanol extracts, and the phenolic content exhibited a positive correlation with the antioxidant activity of M. Sativa extracts.Despite a weaker antioxidant activity, the ethanol extract elicited a calcium spike and suppressed the KCl-induced depolarisation response in neurons, indicating effect on ligand-and/or voltage gated calcium channels. In contrast, the chloroform and water extractsdisplayed no apparent direct functional effects. In conclusion, the antioxidant and functional properties related to phenolic content of Algerian Medicago Sativa L. in water and ethanol extracts, respectively.

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