Hydrophilic Radical Research Articles

Pro-aromatic Natural Terpenes as Unusual "Slingshot" Antioxidants with Promising Ferroptosis Inhibition Activity.

Ferroptosis is a cell death mechanism based on extensive cellular membrane peroxidation, implicated in neurodegenerative and other diseases. The essential oil component γ-terpinene, a natural monoterpene with a unique highly oxidizable pro-aromatic 1,4-cyclohexadiene skeleton, inhibits peroxidation of polyunsaturated lipid in model heterogeneous systems (micelles and liposomes). Upon H-atom abstraction, an unstable γ-terpinene-derived peroxyl radical is formed, that aromatizes to p-cymene generating HOO• radicals. As HOO• are small and hydrophilic radicals, they quickly diffuse outside the lipid core, blocking the radical chain propagation of polyunsaturated lipids. This unprecedented antioxidant "slingshot" mechanism explains why γ-terpinene shows a protective activity against ferroptosis, being effective at submicromolar concentrations in human neuroblastoma (SH-SY5Y) cells.

Synthesis and Characterization of a Biopolymer Pectin/Ethanolic Extract from Olive Mill Wastewater: In Vitro Safety and Efficacy Tests on Skin Wound Healing.

Wound-healing delay is one of the major problems of type 2 diabetes, representing also a clinical emergency in non-healing chronic wounds. Natural antioxidants show interesting wound-healing properties, including those extracted from waste derived from olive oil production. Olive mill wastewater is one of the main by-products of the olive oil-making process, and it is rich in high-value secondary metabolites, mainly hydroxytyrosol. We proposed an eco-friendly extraction method, employing both ultrasound-assisted and Soxhlet techniques and ethanol as a solvent, to recover valuable molecules from Roggianella cv (Olea europea L.) olive mill wastewater, which was further entrapped in a pectin polymer via an enzymatic reaction using porcine pancreatic lipase. Pectin, in combination with other substances, promoted and accelerated wound healing and demonstrated good potential to produce a biomedical conjugate for wound treatment. The antioxidant activity of the extracts and conjugate were evaluated against lipophilic (IC50 equal to 0.152 mg mL-1) and hydrophilic (IC50 equal to 0.0371 mg mL-1) radical species as well as the in vitro cytotoxicity via NRU, h-CLAT, and a wound-healing scratch assay and assessment. The pectin conjugate did not exert hemolytic effects on the peripheral blood, demonstrating interesting wound-healing properties due to its ability to stimulate cell proliferation in a dose-dependent manner.

Effect of growing season on some qualitative and functional attributes of different potato genotypes

AbstractPotato (Solanum tuberosum L.) is a staple food widely consumed in Tunisia and a source of nutrients beneficial for human health. The tubers are, indeed, important source of vitamins, minerals, and bioactive compounds, including carotenoids, polyphenols, and flavonoids. However, data regarding the functional quality of potato varieties grown and consumed in Tunisia are very scarce. For this reason, two field trials were conducted to focus on the effect of the growing season on the functional quality of four potato genotypes (Selena, El Beidha, Naima, and CL07F172.5): a first autumnal trial in Teboulba, Monastir (September 2015–February 2016), which is the late cropping season (LCS) and a second summer cropping season (SCS) in El ksour, El Kef region at an altitude > 1000 m (July 2015–October 2015). Total carotenoids, total phenolics, and flavonoids contents, as well as the hydrophilic radical scavenging activity and lipophilic radical scavenging activity (LRSA) were determined. The obtained results confirmed the importance of potato tubers as a source of bioactive compounds. All quality traits varied significantly among varieties and cropping seasons. Tubers grown under colder weather conditions (LCS: minimum and maximum averages temperatures and relative humidity (RH) ranging between 14.25 and 22.55°C and 25.46% and 83.07%, respectively) accumulated the highest total vitamin C content and exhibited the highest LRSA values. However, temperature and warmer growing conditions (SCS: minimum and maximum averages temperatures and RH ranging between 19.74 and 34.22°C and 35.46% and 87.51%, respectively) probably enhanced the synthesis and accumulation of total carotenoids, total phenolics, and total flavonoids, associated with higher LRSA values.

Impact of Phenolic Acid Derivatives on the Oxidative Stability of β-Lactoglobulin-Stabilized Emulsions.

Proteins, such as β-lactoglobulin (β-Lg), are often used to stabilize oil-water-emulsions. By using an additional implementation of phenolic compounds (PC) that might interact with the proteins, the oxidative stability can be further improved. Whether PC have a certain pro-oxidant effect on oxidation processes, while interacting non-covalently (pH-6) or covalently (pH.9) with the interfacial protein-film, is not known. This study aimed to characterize the impact of phenolic acid derivatives (PCDs) on the antioxidant efficacy of the interfacial β-Lg-film, depending on their structural properties and pH-value. Electron paramagnetic resonance (EPR) analyses were performed to assess the radical scavenging in the aqueous and oil phases of the emulsion, and the complexation of transition metals: these are well known to act as pro-oxidants. Finally, in a model linseed oil emulsion, lipid oxidation products were analyzed over storage time in order to characterize the antioxidant efficacy of the interfacial protein-film. The results showed that, at pH.6, PCDs can scavenge hydrophilic radicals and partially scavenge hydrophobic radicals, as well as reduce transition metals. As expected, transition metals are complexed to only a slight degree, leading to an increased lipid oxidation through non-complexed reduced transition metals. At pH.9, there is a strong complexation between PCDs and the transition metals and, therefore, a decreased ability to reduce the transition metals; these do not promote lipid oxidation in the emulsion anymore.

Superhydrophilic Modification of Polycarbonate Substrate Surface by Organic Plasma Polymerization Film.

Superhydrophilicity performs well in anti-fog and self-cleaning applications. In this study, polycarbonate substrate was used as the modification object because of the low surface energy characteristics of plastics. Procedures that employ plasma bombardment, such as etching and high surface free energy coating, are applied to improve the hydrophilicity. An organic amino silane that contains terminal amine group is introduced as the monomer to perform plasma polymerization to ensure that hydrophilic radicals can be efficiently deposited on substrates. Different levels of hydrophilicity can be reached by modulating the parameters of plasma bombardment and polymerization, such as plasma current, voltage of the ion source, and bombardment time. The surface of a substrate that is subjected to plasma bombarding at 150 V, 4 A for 5 min remained superhydrophilic for 17 days. After 40 min of Ar/O2 plasma bombardment, which resulted in a substrate surface roughness of 51.6 nm, the plasma polymerization of organic amino silane was performed by tuning the anode voltage and operating time of the ion source, and a water contact angle < 10° and durability up to 34 days can be obtained.

Radical Scavenging Activity of Olive Oil Phenolic Antioxidants in Oil or Water Phase during the Oxidation of O/W Emulsions: An Oxidomics Approach.

Omics approaches are recently being applied also in food lipid oxidation, to increase knowledge of oxidation and antioxidation mechanisms. The so-called oxidomics throws a wider spot of light on the complex patterns of reactions taking place in food lipids, especially in dispersed systems. This research aimed to investigate the radical scavenging activity of olive oil phenolic antioxidants (OPAs) in O/W emulsions, as affected by the phase in which they were added. This allowed one to assess whether different behaviors could be expected from antioxidants originally present in phenolic-rich olive oils compared to natural antioxidants added in the water phase during emulsion production. Hydroperoxide decomposition kinetics and the analysis of volatile pattern provided an outline of antioxidation mechanisms. Though being effective in slowing down oxidation when added both in the oil and water phase, OPAs interfered in different ways with oxidation pathways, based on the phase in which they were added. OPAs added to the water phase were more effective in slowing down hydroperoxide decomposition due to the hydrophilic radical initiator. On the other hand, OPAs present in the oil were more effective in preventing radical propagation, with relevant consequences on the volatile pattern.

Synthesis of a Hydrophilic Trityl Radical

Synthesis of a Hydrophilic Trityl Radical

One-pot preparation of zwitterionic sulfoalkylbetaine monolith for rapid and efficient separation of lysozyme from egg white

A porous zwitterionic monolithic column was prepared to rapidly and efficiently separate lysozyme from egg white. The monolith was synthesized in a stainless steel HPLC column (5 cm × 4.6 mm i.d.) by in-situ thermal initiated co-polymerization of N,N-dimethyl-N-methacryloxyethyl-N-(3-sulfopropyl) ammonium betaine (MSA) and ethylene dimethacrylate (EDMA). Due to the combination of quaternary ammonium and sulfonic groups on the monolithic matrix in one-pot process, the hydrophobic carbon chain and hydrophilic radical were obtained, which provided multiple driving forces for neutral, basic and acidic analytes, thus mix-mode chromatography mechanism contributed to the retention of different charged proteins. Properties such as composition, morphology and stability of the MSA-co-EDMA monolithic column were characterized by various analytical methods and the results showed that the monolith has large through-pores, good hydrophilicity and permeability. The effects of mobile phase pH and ionic strength on proteins were investigated, drawing the conclusion that the main adsorption and elution mechanism of lysozyme on MSA-co-EDMA monolith was electrostatic interaction, while those of other proteins included hydrophobic, hydrophilic and electrostatic interactions. Therefore, efficient separation of lysozyme and other proteins could be successfully achieved by switching the pH of mobile phase. Lysozyme can be adsorbed using 20 mmol/L phosphate buffer (pH 7.0) and eluted with 20 mmol/L phosphate buffer (pH 2.0). To prove the practicality of the monolithic column, it was also applied in the separation of lysozyme in egg white, which means the work has the potential for further development in proteome analysis of real biological samples.

Mate extract is superior to green tea extract in the protection against chicken meat protein thiol oxidation

Water soluble caffeic acid derivatives in aqueous extracts of mate (Ilex paraguariensis) showed a direct dose-dependent response, protecting protein thiols in a chicken breast meat model system when oxidation was initiated by a lipophilic radical initiator (2,2′-azobis(2,4-dimethylvaleronitrile; AMVN). In contrast, an inverse dose-dependent response was obtained when initiated by a hydrophilic radical initiator (2,2′-azobis(2-amidinopropane)dihydrochloride; AAPH), pointing toward a mechanism, where a specific concentration of water-soluble polyphenol yields optimum protection. Optimal concentrations of mate extract for the protection of thiols against radicals initiated in the lipid phase (AMVN) or in the aqueous phase (AAPH) were 0.1–0.5% and 0.01–0.1%, respectively. Green tea (Camellia sinensis) extract showed a pro-oxidative effect involving quinones from oxidation of pyrogallol-type catechins (epigallocatechin-3-gallate (EGCG), gallocatechin-3-gallate (GCG), and epicatechin-3-gallate (ECG)) and not the catechol-type catechins (catechin and epicatechin).

A radical containing injectable in-situ-oleogel and emulgel for prolonged in-vivo oxygen measurements with CW EPR

Molecular oxygen, reactive oxygen species and free radicals derived from oxygen play important roles in a broad spectrum of physiological and pathological processes. The quantitative measurement of molecular oxygen in tissues by electron paramagnetic resonance (EPR) has great potential for understanding and diagnosing a number of diseases, and for developing and guiding therapies. This requires improvements in the free radical probe systems that sense and report molecular oxygen levels in vivo. We report on the encapsulation of existing free radical probes in lipophilic gel implants: an in-situ-oleogel and an emulgel, based only on well-known, safe excipients for the incorporation of lipophilic and hydrophilic radicals, respectively. The EPR signals of encapsulated radicals were not altered compared to dissolved radicals. The high solubility of oxygen in lipophilic solvents enhanced oxygen sensitivity. The gels extended the lifetime of the radicals in tissues from tens of minutes to many days, simplifying studies with extended series of measurements. The encapsulated radicals showed a good in vivo response to changes in oxygen supply and seem to circumvent concerns from toxicity of the radical probes. These gels simplify the development of new oxygen-sensitive free radical probes for EPR oximetry by making their in vivo stability, persistence and toxicity a function of the encapsulating gel and not a set of additional requirements for the free radical probe.

Organic Batteries: An Ultrahigh Output Rechargeable Electrode of a Hydrophilic Radical Polymer/Nanocarbon Hybrid with an Exceptionally Large Current Density beyond 1 A cm−2 (Adv. Mater. 26/2018)

Organic Batteries: An Ultrahigh Output Rechargeable Electrode of a Hydrophilic Radical Polymer/Nanocarbon Hybrid with an Exceptionally Large Current Density beyond 1 A cm⁻² (Adv. Mater. 26/2018)

An Ultrahigh Output Rechargeable Electrode of a Hydrophilic Radical Polymer/Nanocarbon Hybrid with an Exceptionally Large Current Density beyond 1 A cm-2.

Facile charge transport by a hydrophilic organic radical-substituted polymer and the 3D current collection by a self-assembled mesh of single-walled carbon nanotube bundles lead to the operation of an ultrahigh-output rechargeable electrode. Exceptionally large current density beyond 1 A cm-2 and high areal capacity around 3 mAh cm-2 are achieved, which are 101-2 times larger than those of the previously reported so-called "ultrafast electrodes." A sub-millimeter-thick, flexible, highly safe organic redox polymer-based rechargeable device with an aqueous sodium chloride electrolyte is fabricated to demonstrate the superior performance.

Comparative study of biocorrective protein-peptide agent to improve quality and safety of livestock products

Water with modified isotopic composition (D/H = 40 ppm) as a solubilizing agent for biologically active substances extraction from immune organs Sus Scrofa increases protein yield in thymus to 20%, in spleen up to 38%, mesenteric lymph nodes up to 35% in comparison with distilled water (D/H = 150 ppm). It was found a significant amount of neurotransmitter amino acids, such as aspartic and glutamic acids, glycine (thymus - 10.5; 13.7; 7.6%; spleen - 12.2; 10.7; 7.8% lymph nodes - 11.0; 13.3; 11.1%, respectively) having the immunological and adaptogenic activity, in extracts of Sus scrofa immunocompetent organs (thymus, spleen, mesenteric lymph nodes). Application of water with modified isotopic composition as solubilizing agent (D / H = 40 ppm) for extraction of immunocompetent organs' biologically active compounds led to increased amino acid content, including hydrophilic amino acids, in thymus extracts - up to 22%, in spleen extracts - up to 15% , in lymph nodes exctracts - up to 8%, in comparison to distilled water (D / H = 150 ppm). Peptide profile analysis revealed positive effect of water (D/H = 40 ppm) on a quality protein content extracts in molecular weight range from 10 to 20 kDa and from 30 to 45 kDa and peptide composition (2 kDa), at the same time quantitative content of compounds adaptogenic and immunocorrective action increased. Reducing of deuterium content in the solubilizing agent enhances quantitative amino acid content, i.e. extraction in an aqueous- salt solution based on deuterium depleted water of animal tissues with a high content of amino acids with hydrophilic radicals proceeded more completely.

Effect of defatted sesame meal extract on phospholipid peroxidation in liposomes

We compared the protective effect of defatted sesame meal extracts (DSMEs; prepared either after roasting sesame seeds at 200°C for 60 min or without roasting) on phospholipid peroxidation of liposomes, with the protective effect of natural antioxidants (ascorbic acid and α-tocopherol). We investigated phospholipid peroxidation after induction with either a hydrophilic radical generator (2,2′-azobis [2-amidinopropane]) or a hydrophobic radical generator (2,2′-azobis [2,4-dimethylvaleronitrile]), for 6 h at 37 and 50°C. Added antioxidants prevented peroxidation of phospholipids in liposomes, and roasted DSME showed a significantly stronger antioxidant activity than unroasted DSME in all cases. The results indicate that heat treatment significantly increases the protective effect of DSME on lipid peroxidation in phospholipid bilayers under both hydrophilic and hydrophobic conditions, regardless of the hydrophobicity of the radical generators.

Synthesis, Characterization, and Nanoencapsulation of Tetrathiatriarylmethyl and Tetrachlorotriarylmethyl (Trityl) Radical Derivatives—A Study To Advance Their Applicability as in Vivo EPR Oxygen Sensors.

Tissue oxygenation plays an important role in the pathophysiology of various diseases and is often a marker of prognosis and therapeutic response. EPR (ESR) is a suitable noninvasive oximetry technique. However, to reliably deploy soluble EPR probes as oxygen sensors in complex biological systems, there is still a need to investigate and improve their specificity, sensitivity, and stability. We reproducibly synthesized various derivatives of tetrathiatriarylmethyl and tetrachlorotriarylmethyl (trityl) radicals. Hydrophilic radicals were investigated in aqueous solution mimicking physiological conditions by, e.g., variation of viscosity and ionic strength. Their specificity was satisfactory, but the oxygen sensitivity was low. To enhance the capability of trityl radicals as oxygen sensors, encapsulation into oily core nanocapsules was performed. Thus, different lipophilic triesters were prepared and characterized in oily solution employing oils typically used in drug formulations, i.e., middle-chain triglycerides and isopropyl myristate. Our screening identified the deuterated ethyl ester of D-TAM (radical 13) to be suitable. It had an extremely narrow single EPR line under anoxic conditions and excellent oxygen sensitivity. After encapsulation, it retained its oxygen responsiveness and was protected against reduction by ascorbic acid. These biocompatible and highly sensitive nanosensors offer great potential for future EPR oximetry applications in preclinical research.

Analysis on Composition and Antioxidative Properties of Phlorotannins Isolated from Japanese Eisenia and Ecklonia Species

The composition and antioxidative properties of crude phlorotannins isolated from Japanese Eisenia and Ecklonia species including cultured E. kurome were analyzed. As a result of liquid chromatography mass spectrometry analysis, it was suggested that the phlorotannins were composed of compounds containing 3 - 7 phloroglucinol units for Eisenia species and 3 - 8 phloroglucinol units for Ecklonia species. The antioxidant properties of phlorotannins were evaluated using the hydrophilic oxygen radical absorbance capacity (H-ORAC) assay, the measurements of superoxide anion radical scavenging activity (SOSA) with electron spin resonance method, and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and reducing power assay. It was clarified that the phlorotannins contained H-ORAC values of 8.9 × 103 - 1.0 × 104 μmol-Trolox equivalents (TE)/g, SOSA of 1.5 × 104 - 2.9 × 104 superoxide dismutase units/g, DPPH radical scavenging activity of 4.7 × 103 - 5.5 × 103 μmol-TE/g, and reducing power of 6.5 × 102 - 7.0 × 102 mg-ascorbic acid equivalents/g, and had excellent antioxidative properties.

Spices and Herbs May Improve Cardiovascular Risk Factors

Traditional risk factors for cardiovascular disease (CVD) include high blood low-density lipoprotein (LDL) cholesterol, low high-density lipoprotein (HDL) cholesterol, high blood pressure, smoking, and diabetes. Family history and inflammatory factors also affect CVD risk. Diet therapy for treating and managing patients with CVD and for reducing risk among healthy individuals focuses on consuming a diet containing vegetables and fruits; eating whole-grain breads and cereals; choosing poultry, fish, nuts, legumes, and low-fat dairy foods; and limiting the intake of saturated fat, trans-fat, sweets, sugar-sweetened beverages, and red meats. 1 Because spices and herbs are rich in potentially bioactive compounds, clinical studies have examined their effects on blood insulin, blood lipids, and inflammation. EFFECTS OF A SPICE BLEND ON POSTPRANDIAL INSULIN, TRIGLYCERIDES, AND ANTIOXIDANT CAPACITY We designed a pilot study to determine whether a single, large dose (14 g) of a high-antioxidant spice blend incorporated into a test meal caused postprandial blood changes. 2 Six overweight men aged 30 to 65 years were recruited, baseline blood samples were taken, and the men were randomized to 2 test conditions: a control meal consisting of a dessert biscuit, coconut chicken, and cheese bread, or the same control meal with an added spice blend that included black pepper, cinnamon, cloves, garlic powder, ginger, oregano (Mediterranean), paprika, rosemary, and turmeric. Participants could not be blinded to the test condition because of the relatively large amount of spice blend used. Postprandial blood samples were taken immediately after the meal and every 30 minutes thereafter until 8 samples were collected. Blood lipids, glucose, and insulin were measured. The plasma was analyzed for hydrophilic, lipophilic, and total oxygen radical absorbance capacity (ORAC) to provide information about its antioxidant potential. A higher total antioxidant capacity may reflect reduced oxidative stress, which is an underlying cause of many chronic diseases. 3 Addition of spices and herbs to the test meal significantly decreased postprandial insulin area under the curve by 21% (P = .004) and triglycerides area under the curve by 31% (P = .048), as shown in the Figure. Hydrophilic ORAC levels were 13% higher (P = .02) following the spice test meal than following the control meal, whereas lipophilic and total ORAC levels did not differ between the meals. Total blood cholesterol, HDL cholesterol, and glucose levels were not affected by meal condition. These findings suggest that a blend of spices and herbs may help improve levels of postprandial insulin and triglyceride concentrations after a high-fat meal while alsoenhancingthe antioxidative capacity of blood.

β-Carotene as a membrane antioxidant probed by cholesterol-anchored daidzein.

β-Carotene is found to be more effective as an antioxidant in phosphatidylcholine (PC) liposomes when protecting against hydrophilic radicals compared to lipophilic radicals, as measured by the rate of formation of conjugated dienes. Daidzein alone is without effect, but decreases the antioxidative effect of β-carotene for hydrophilic initiation and increases the effect for lipophilic initiation. The newly synthesized 7-cholesterylglycol daidzein has the opposite effect for β-carotene as antioxidant, with a strong enhancement for hydrophilic initiation and a slight decrease for lipophilic initiation. Redistributing β-carotene to membrane surfaces by cholesterol-anchoring of daidzein enhances protection against aqueous radicals significantly at the expense of protection against lipid-derived radicals. Anchoring of daidzein to cholesterol is concluded to be useful as a mechanistic tool for controlling antioxidant distribution in membranes sensitive to radical damage, as supported by quantum mechanical calculation within the density function theory and further supported by fluorescence probes and fluorescence polarization probes.

Reversible surface wettability conversion of graphene films: optically controlled mechanism

Graphene films which are fabricated by simple dispensing method without surface modification exhibit reversible switching between superhydrophobicity and superhydrophilicity under alternative UV illumination and dark storage. Careful study of the mechanisms is conducted in view of surface geometry, microstructure, and chemical compositions, and focused on chemical compositions. Photo-induced chemisorption of hydrophilic radicals and water molecules on graphene is found to be responsible for the transition from original hydrophobicity to hydrophilicity, even superhydrophilicity, while replacement of water molecules by oxygen during storage in the dark environment induces the hydrophobicity recovery of graphene films from hydrophilic state. Appearance and disappearance of hydroxyl radicals are closely related to the lattice structure of graphene and energy supply. This wettability conversion is fully reversible. The outcomes not only reveal micro-processes involved in wettability conversion of graphene but also help to purposely design and produce devices from carbon materials with tailor-made tunable surface wettability according to our actual need.

Monodisperse SnO2 nanocrystals functionalized multiwalled carbon nanotubes for large rate and long lifespan anode materials in lithium ion batteries

A facile way towards high rate and long lifespan anode materials based on SnO2 and commercial multiwalled carbon nanotubes (MWCNTs) is readily achieved through a combination of activation and hydrothermal treatment. The former endows the MWCNTs with abundant hydrophilic radicals, while the latter guarantees intimate connection between SnO2 and MWCNTs; eventually, monodisperse SnO2 nanocrystals ca. 3nm are firmly anchored on the MWCNTs without agglomeration. When used for lithium ion batteries (LIBs) anodes, the hybrid composite exhibits excellent cycling capability with high reversible capacity about 700 mAh g−1 (based on total weight of the composite) for 150 cycles at 0.1 A g−1 superior to both components involved. Besides large rates of 5 A g−1 with recoverable initial reversible capacity, it also last for more than 1000 cycles with little capacity decay, outperforming most SnO2 based carbon nanotubes composites (SnO2/CNTs) so far. Insights into the electrochemical processes reveal the hybrid composite exhibits enhanced redox capacitance and interfacial capacitance in comparison with SnO2 nanocrystals which indicate the perfect interfaces and robust structure of the hybrid composite.