Radical Salts Research Articles

3D Spin-Liquid State in an Organic Hyperkagome Lattice of Mott Dimers.

We report the first 3D spin liquid state of isotropic organic spins. Structural analysis, and magnetic and heat-capacity measurements were carried out for a chiral organic radical salt, (TBA)_{1.5}[(-)-NDI-Δ] (TBA denotes tetrabutylammonium and NDI denotes naphthalene diimide), in which (-)-NDI-Δ forms a K_{4} structure due to its triangular molecular structure and an intermolecular π-π overlap between the NDI moieties. This lattice was identical to the hyperkagome lattice of S=1/2 Mott dimers, and should exhibit 3D spin frustration. In fact, even though the high-temperature magnetic susceptibility followed the Curie-Weiss law with a negative Weiss constant of θ=-15 K, the low-temperature magnetic measurements revealed no long-range magnetic ordering down to 70mK, and suggested the presence of a spin liquid state with a large residual paramagnetism χ_{0} of 8.5×10^{-6} emu g^{-1} at the absolute zero temperature. This was supported by the ^{14}N NMR measurements down to 0.38K. Further, the low-temperature heat capacities c_{p} down to 68mK clearly indicated the presence of c_{p} for the spin liquid state, which can be fitted to the power law of T^{0.62} in the wide temperature range 0.07-4.5K.

Various Antioxidant Effects Were Attributed to Different Components in the Dried Blossoms of Citrus aurantium L. var. amara Engl.

Citrus aurantium L. var. amara Engl. (CAVA) was traditionally used as an edible and medicinal material in China. Total flavonoids (CAVAF), alkaloids (CAVAA), polysaccharides (CAVAP), coumarins (CAVAC), and neroli (CAVAO) were extracted from CAVA. Hesperidin, naringin, and neohesperidin composed 83.94% of CAVAF, and synephrine represented 50.56% of CAVAA. On the basis of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH•), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical cation (ABTS• +), hydroxyl radical (•OH), ferric-reducing antioxidant power (FRAP), and reducing power assays, the antioxidant activities of five components were comprehensively and comparatively investigated. CAVAF had a stronger DPPH• scavenging effect and FRAP and reducing power. CAVAP and CAVAA exhibited comparable •OH scavenging effects to vitamin C. CAVAA showed the highest ABTS• + scavenging activity. In conclusion, different constituents varied significantly toward different sources of free radicals and other oxidants. It is obvious that CAVA has various antioxidant effects, which are attributed to different components.

Direct reduction of metal ions based on perylene diimide derivative radical anion as an electron-transfer mediator and potential application in detection of oxidizing metal ions

Radical anion or radical anion salt of two perylene diimide derivatives were obtained by intermolucular electron transfer (solution as electron donor) and alkali treatment. The stable metal ions with high potential were reduced to corresponding metallic state or lower valence metal ions based on the perylene diimide derivative radical anion as an electron- transfer mediator. Based on this reaction mechanism, the radical anion salt showed high optical sensitivity to the oxidizing metal ions, and the detection limit of Fe3+ and Cu2+ can reached 0.057μM and 0.00215μM, respectively.

Antioxidant activities and phytochemical constituents of Antidesma thwaitesianum Müll. Arg. leaf extracts

ObjectiveTo investigate the antioxidant activities as well as phytochemical constituents of Antidesma thwaitesianum Müll. Arg. leaf extracts. MethodsThe leaves of A. thwaitesianum were extracted using three different methods: blending with distilled water, maceration with ethanol and decoction. The chemical antioxidant activity of the plant leaf extracts was evaluated using 2,2-diphenyl-1-picryhydrazyl (DPPH) radical and 2,2′-azinobis(3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS+) radical scavenging assays, as well as the ferric reducing antioxidant power assay. Cellular antioxidant activity was determined by superoxide and nitric oxide scavenging assays. The cytotoxicity of the leaf extracts in RAW 264.7 and differentiated HL-60 cells was tested in parallel using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide and 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assays, respectively. The total phenolic and flavonoid contents were also assessed by spectrophotometric analysis. Phytochemical constituents of the most potent extract were investigated by liquid chromatography with an electrospray ionization quadrupole time-of-flight mass spectrometer (LC-ESI-QTOF-MS/MS). ResultsThe ethanolic (ME) and decoction (LW) extracts of dried leaves had the highest chemical scavenging activity against DPPH and ABTS+ free radicals with half maximal effective concentration (EC50) values ranging from 3.54 to 6.44 μg/mL. ME and LW exerted moderate ferric reducing activity, with ferric reducing antioxidant power values of 847.41 and 941.26 mg Fe2+/g extract, respectively. Similarly, ME showed potent cellular scavenging activity against superoxide and nitric oxide radicals with EC50 values of 58.12 and 71.90 μg/mL, respectively. However, LW exhibited only strong nitric oxide scavenging activity with an EC50 value of 91.20 μg/mL. The cell viability of RAW 264.7 and HL-60 cells was greater than 70% in all tested concentrations of both extracts, thus confirming the absence of their cytotoxicity. ME and LW contained high total phenolic contents of 231.14 and 274.42 mg gallic acid equivalents per gram, respectively, as well as high total flavonoid contents of 18.82 and 22.17 mg quercetin equivalents per gram, respectively. LC-ESI-QTOF-MS/MS analysis revealed the presence of 52 structurally characterized compounds in ME, 43 of which were tentatively identified. Hydroxycinnamic acids such as caffeic acid and its derivatives were the predominant phenolic compounds. ConclusionThis is the first report describing potent chemical and cellular antioxidant effects of the ethanolic leaf extract of A. thwaitesianum. The extract contained high total phenolic and flavonoid contents. LC-ESI-QTOF-MS/MS analysis further revealed an abundance of caffeic acid derivatives and flavonoids. These data support its potential use as dietary supplements in oxidative stress prevention.

Facile Construction of Quinoline-2-carboxylate Esters through Aerobic Oxidation of Alkyl 4-Anilinocrotonates Induced by a Radical Cation Salt.

A facile construction of quinoline-2-carboxylate esters through an aerobic oxidation of alkyl 4-anilinocrotonates is described. In the presence of dioxygen, sp3 C-H bonds in 4-anilinocrotonates can easily be oxidized by using a catalytic amount of a radical cation salt, providing a radical intermediate. After further oxidation and domino cyclization, the desired quinoline derivatives were afforded in high yields. This reaction provides a new way to construct the pharmaceutically relevant quinoline skeleton, avoiding harsh reaction conditions and tedious starting material synthesis.

Potential antioxidant and lipid peroxidation inhibition of Phyllanthus acidus leaf extract in minced pork.

ObjectiveThis study investigated the effect of extraction solvents on antioxidant bio-active compounds as well as potential antioxidant and lipid peroxidation inhibition of Phyllanthus acidus (P. acidus) leaf extract in minced pork.MethodsThe effect of various solvent systems of water, 25%, 50%, 75% (v/v) ethanol in water and absolute ethanol on the extraction crude yield, total phenolic content, total flavonoid content and in vitro antioxidant activities of P. acidus leaves was determined. In addition, antioxidant activities of the addition of crude extract from P. aciuds leaves at 2.5 and 5 g/kg in minced pork on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical cation decolorization, reducing power and inhibition of lipid peroxidation (thiobarbituric acid reactive substances; TBARS) were determined. Moreover, sensory evaluation of the samples was undertaken by using a 7-point hedonic scale.ResultsThe results showed that the highest crude yield (2.8 g/100 g dry weight) was obtained from water which also had the highest recovery yield for total phenolic content, total flavonoid content and the strongest antioxidant activity. The addition of crude water extract from P. acidus leaves was more effective in retarding lipid peroxidation and higher antioxidant activity than control and butylated hydroxytoluene in minced pork. In particular, the samples containing P. acidus extract had no significant effect on the sensory scores of overall appearance, color, odor, texture, flavor, and overall acceptability compared to the control.ConclusionWater solvent was an optimally appropriate solvent for P. acidus leaf extraction because of its ability to yield the highest amount of bio-active compounds and in vitro antioxidant property. Particularly, P. acidus crude water extract also strongly expressed the capacity to retard lipid oxidation, radical scavenging, radical cation decolorization and reducing power in minced pork. The results of this study indicated that P. acidus leaf extract could be used as natural antioxidant in the pork industry.

Antioxidant and anticancer activities of Plectranthus stocksii Hook. f. leaf and stem extracts

The properties of Plectranthus stocksii—a well-known folk medicinal plant—were investigated. The plant extracts were successively extracted and tested for phytochemicals using high performance liquid chromatography, while antioxidant and anticancerous properties were assessed using MCF-7, Caco-2 and RAW 264.7 cancerous cell line models. The methanolic extract of leaves showed higher concentrations of total phenolics (415.41 mg gallic acid equivalents/g extract) and tannins (177.53 mg gallic acid equivalents/g extract) contents than other studied extracts. In the case of flavonoids, ethyl acetate extract of leaf (LEA) showed a higher concentration (777.11 mg rutin equivalents/g extract) and was also found to have better antioxidant activity against stable radical 2,2-diphenylpicrylhydrazyl (3.46 μg/mL), 2,2′azinobis (3-ethylbenzothiozoline-6-sulfonic acid) disodium salt radical (27.41 mM Trolox equivalent/g extract) and superoxide (24.16 μg/mL) radicals and showed better IC50 (the concentration of the sample at which the inhibition rate reaches 50%) values on MCF-7 (48.874 μg/mL) and Caco-2 (36.088 μg/mL) cancerous cell line models. The immense anti-oxidant potential of P. stocksii leaf and stem extracts could be utilized as a good source of natural, anti-oxidant supplement in food to defend against oxidative-stress-related disorders and more generally in the food safety industry.

Organic field-effect transistor based on paramagnetic Cu(II) neutral complexes coordinated by Schiff base-type TTF ligands

We have succeeded in preparation of novel paramagnetic Cu(II) complexes composed of tetrathiafulvalene (TTF)-based ligands as electrical conducting units, [CuII(Bz-OMe-tBu-sae-TTF)2], [CuII(EDT-bissae-TTF)] and [CuII(Bz-bis(OMe-tBu-sae)-TTF)]. Electrochemical measurements of these neutral complexes revealed that they exhibited two pairs of redox waves attributed to the oxidation of TTF moieties. Among the newly synthesized TTF complexes, only [CuII(EDT-bissae-TTF)] gave a radical salt by electrochemical crystallization, but its resistive behavior was insulating. Field-effect transistors (FET) were fabricated with spin-coated films of [CuII(Bz-OMe-tBu-sae-TTF)2] and [CuII(EDT-bissae-TTF)], and their FET performances were very low compared with the conventional organic thin film transistors (OTFT) based on TTF derivatives. Atomic force microscopy (AFM) images of the spin-coated films indicated the non-uniform film surfaces with many small grains leading to the large grain boundaries, which probably causes the low carrier mobility of the FET devices.

Synthesis of short retinoidal amides related to fenretinide: antioxidant activities and differentiation-inducing ability.

By a scaffold shortening strategy, a small series of retinoidal amides fenretinide (4-HPR) analogs have been synthesized from α, β-ionones and tested for their antiproliferative and differentiating activities, and antioxidant effect. The antiproliferative activity and triggering of apoptosis of our short retinoids were evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and 4'-6-diamidino-2-phenylindole staining and microscope evaluation after 3- or 6-day exposure, while their differentiating activity was established by the analysis of the expression of the CD11b marker of differentiation in treated HL60 target cells and by the superoxide production assayed colorimetrically by the nitro blue tetrazolium-reducing activity assay. Finally, the antioxidant activity was determined by the 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulphonic acid) diammonium salt radical cation decolourisation assay utilizing the antioxidant Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid) as reference (Trolox equivalent antioxidant capacity, or TEAC). Docking analysis was performed to study the binding features to the Retinoic Acid Receptor alpha (RARα). While no pharmacologically relevant antiproliferative activity was evidenced, some of our short retinoids showed a differentiating and antioxidant activity similar to that of 4-HPR. In particular, compound 2b6 displayed a scavenging activity two times more efficient than 4-HPR itself. Finally, the docking analysis showed that these short retinoids, like 4-HPR, bind to the RARα protein with good fitness scores. Our data could pave the way for the design of new potent and less toxic antioxidant and differentiating compounds related to 4-HPR.

Extraction of total alkaloids, peimine and peiminine from the flower of Fritillaria thunbergii Miq using supercritical carbon dioxide

This study for the first time designed to use supercritical fluid extraction (SFE) to extract total alkaloids, peimine and peiminine from the flower of Fritillaria thunbergii Miq. 2,2′-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) diammonium salt radical cation scavenging activity (ABTS-RSA) and ferric reducing antioxidant potential (FRAP) assay were selected to evaluate the antioxidant capacity of the extracts. A central composite design (CCD) with four variables (extract time (1.5–3.5) h, temperature (50–70)°C, pressure (15–35) MPa and co-solvent (ethanol: water) ratio (80–100, v/v) %was employed for optimization of process parameters, and response surface plots were constructed in accordance with a second order polynomial model. The highest yields of total alkaloids (2.9mg/g), peimine (0.7mg/g) and peiminine (0.07mg/g) were predicted at optimal conditions of 2.9h, 61.3°C, 30.6MPa and 90.3% ethanol and the antioxidant activity of the extracts was estimated to be comparable to that of α-tocopherol with ABTS value of 0.5mg/mL and FRAP value of 658mg AAE/100g, respectively. These results suggest that optimization of the extraction conditions is critical for accurate quantification of total alkaloids, peimine and peiminine, and antioxidants in F. thunbergii Miq flower, which may further be used for industrial extraction procedure.

Low-Cost and Sustainable Organic Thermoelectrics Based on Low-Dimensional Molecular Metals.

Thermoelectric generator composed of crystalline radical ion salts: The unipolar charge transport along the molecular stacks facilitates complementary p- and n-type organic thermoelectric materials of high electrical conductivity and of 1D electronic structure. The specific power output of 5 mW cm-2 and the zT > 0.15 below 40 K demonstrate a new field of low-temperature thermoelectric applications unlocked by organic metals.

New Ethylenedithio-TTF Containing a 2,2,5,5-Tetramethylpyrrolin-1-yloxyl Radical through a Vinylene Spacer and Its FeCl4− Salt—Synthesis, Physical Properties and Crystal Structure Analyses

To develop novel magnetic conductors exhibiting conducting/magnetic bifunctionalities and peculiar responses to applied magnetic fields, we synthesized new EDT-TTF (ethylenedithiotetrathiafulvalene) donor containing a 2,2,5,5-tetramethylpyrrolin-1-yloxyl radical through a π-conjugated vinylene spacer 1 and examined its electronic and crystal structures, and physical properties. We also prepared its cation radical salts by an electrochemical oxidation method and successfully cleared the crystal structures and magnetic properties of the cation radical salts, 1·FeCl4 and 1·GaCl4. These salts have strongly dimerized one-dimensional arrays of the fully oxidized donor molecules, giving rise to the formation of spin-singlet state of the π cation radical spins in the dimer. On the other hand, the FeCl4- anion locates on the side of the dimers with very short S-Cl contacts and mediates very strong π-d interaction between the donor and anion moieties, resulting in the antiferromagnetic behavior of the Weiss temperature of θ = -3.9 K through its d-π-d interaction.

Changes in the phenolic compounds and antioxidant activities of mustard leaf (Brassica juncea) kimchi extracts during different fermentation periods.

This study was conducted to investigate the changes in the total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activities of 80% methanol and water extracts from mustard leaf kimchi during different fermentation periods. The methanol extract exhibited higher TPC and TFC than the water extract. Both extracts from kimchi fermented for two months showed the highest antioxidant effects against the scavenging activities of 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radicals and 2,2-azino-bis diammonium salt (ABTS) radicals. Moreover, the methanol extract from kimchi fermented for two months showed the highest nitrite scavenging activity. The highest metal (Fe2+) chelating effect of the methanol extract and water extract was observed after three months and one month, respectively. Caffeic acid showed the highest increase with fermentation. These findings suggest that the antioxidant activities of kimchi depend on the fermentation period. Accordingly, this study provides basic data for improving the antioxidant activity of mustard leaf kimchi through the establishment of their fermentation period.

High Electrical Conductivity and Conspicuous Phase Transitions in Single Crystals of K-TCNQ

This paper is to report the temperature dependent electrical conductivity of single crystals of radical ion salt (RIS) potassium-TCNQ (K-tetracyanoquino- dimethane) in a wide range of temperatures from 30 to 500 K. This RIS is quasi-one-dimensional in nature. These single crystals of K-TCNQ are grown by different methods like electrochemical, solution growth and diffusion method. Activation energy is determined for the sample in different temperature regions and found different values. More than one semiconductor to metal phase transition is observed in the studied samples during electrical measurements below and above room temperature. All the features observed in the studied samples are analyzed in the framework of their molecular structure as well as under different effects like disorder, impurity, Coulomb interaction, charge density wave (CDW), scattering and 3-D effects etc.

Radical anion and dianion salts of titanyl macrocycles with acceptor substituents or an extended π-system

Crystalline anionic salts of titanyl macrocycles with acceptor substituents or an extended π-system have been obtained for the first time: (PPN+)2{O[double bond, length as m-dash]TiIV(PcCl84-)}2- (1), (PPN+){O[double bond, length as m-dash]TiIV(Nc˙3-)}˙-·2C6H4Cl2 (2) and (PPN+)2{O[double bond, length as m-dash]TiIV(AceTPrzPz4-)}2-·1.3C6H4Cl2·0.8C6H5CN (3) where PPN+ is the bis(triphenylphosphoranylidene)ammonium cation, PcCl8 - 2,3,9,10,16,17,23,24-octachlorophthalocyanine; Nc - 2,3-naphthalocyanine, AceTPrzPz - tetra(acenaphthenopyrazino)porphyrazine. Salts 1-3 were obtained in the reduction of the parent titanyl macrocycles by fluorenone ketyl in the presence of an excess of PPNCl in o-dichlorobenzene with following precipitation of crystals with n-hexane. Reduction of macrocycles in 1-3 is accompanied by the appearance of intense NIR bands in the solid spectra at 963-1159 nm. It has been found that the extended π-system with linear annulation in {O[double bond, length as m-dash]TiIV(Nc˙3-)}˙- provides the shift of the NIR band to smaller energies (1159 nm) in comparison with those in the spectra of {O[double bond, length as m-dash]TiIV(Pc˙3-)}˙- (995-998 nm). Reduction of macrocycles leads also to the alternation of C-Nimine bonds due to partial disruption of their aromaticity. The disruption is higher for the dianions in 1 and 3 in comparison with the radical anions in 2. One-dimensional π-π stacking chains and layers are formed in 1 and 3 with diamagnetic {O[double bond, length as m-dash]TiIV(PcCl84-)}2- and {O[double bond, length as m-dash]TiIV(AceTPrzPz4-)}2- dianions, respectively. Salt 2 contains nearly isolated [{O[double bond, length as m-dash]TiIV(Nc˙3-)}˙-]2 dimers with a strong π-π interaction between paramagnetic radical anion macrocycles. As a result, a transition from the triplet to singlet state with antiparallel ordering of spins within the dimers is observed in 2 below 200 K.

Antioxidant Activity and Inhibitory Potential of Cistus salviifolius (L.) and Cistus monspeliensis (L.) Aerial Parts Extracts against Key Enzymes Linked to Hyperglycemia.

Cistus genus (Cistaceae) comprises several medicinal plants used in traditional medicines to treat several pathological conditions including hyperglycemia. These include Cistus salviifolius L. (CS) and Cistus monspeliensis L. (CM), still not fully explored as a source of metabolites with therapeutic potential for human diseases. In this study, the antioxidant α-amylase and α-glucosidase enzyme inhibitory effects of aqueous and hydromethanolic extracts from the aerial parts of Moroccan CS and CM were investigated. Antioxidant activity has been assessed using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radicals and ferric reducing/antioxidant power (FRAP) methods. The α-amylase and α-glucosidase inhibitory activity has been assessed using an in vitro model. Moreover, mineral and phenolic contents of CS and CM were analyzed. The extracts of both species exhibited potent antioxidant activity in all used systems and possess strong inhibitory effect towards α-glucosidase (IC50: 0.95 ± 0.14 to 14.58 ± 1.26 μg/mL) and significant inhibitory potential against α-amylase (IC50: 217.10 ± 0.15 to 886.10 ± 0.10 μg/mL). Furthermore, the result showed high levels of phenolic content and unexpectedly some higher levels of mineral content in CS. The results suggest that the phenolic rich extracts of CS and CM may have a therapeutic potential against diseases associated with oxidative stress and may be useful in the management of hyperglycemia in diabetic patients.

Crystalline salts of metal phthalocyanine radical anions [M(Pc˙3−)]˙− (M = CuII, PbII, VIVO, SnIVCl2) with cryptand(Na+) cations: structure, optical and magnetic properties

Radical anion salts of metal phthalocyanines (M = CuII, PbII, VIVO and SnIVCl2) with the {cryptand(Na+)} cations have been obtained and studied.

Nanostructural point-contact sensors for diagnostics of carcinogenic strains of Helicobacter pylori

Background: The problem of detecting the different strains of H. pylori has gained great importance today due to the worldwide prevalence of this bacterium and its role in the pathogenesis of a number of serious gastric and extragastric diseases. However, not all H. pylori strains are aggressive and require antibiotic treatment. Thus, the question arises about the necessity of differentiating these bacterium strains with respect to their virulence factors. In accordance with the IV Maastricht Consensus Report, among the variety of ways to diagnose H. pylori infection, non-invasive methods should be given preference. Most of them are based on the analysis of gas which is exhaled by a human. Mass spectrometry, gas chromatography, and IR spectroscopy are currently the mostly used ones. However, despite the obvious advantages, these techniques have a number of disadvantages that make them difficult to use in everyday medical practice. Modern sensor devices can become an inexpensive and easy to access alternative to these technologies. Objectives: The aim of the work is to develop a new type of sensor device for selective recognition of H. pylori strains which is based on analysis of a mixture of gases exhaled by human. Such a kind of device can be designed on the basis of a point-contact gas sensor. Materials and methods: Anion-radical salts of the organic conductor TCNQ were chosen as the sensitive material for point-contact sensors. The fundamental properties of point contacts which are used in the Yanson point-contact spectroscopy make it possible to create a point-contact mesoscopic matrix on the basis of this material, which is sensitive to small concentrations of components in complex gas media. The sensors were obtained by electrochemical deposition of salts from a solvent characterized by a high vapor pressure on a textolite substrate. Gas exhaled by a human served as the substance to be analyzed. The measurements were carried out following a specially developed technique. The sensor response curves were recorded by a measuring complex and original software designed by the authors. Results: A set of 350 active-type TCNQ-based sensors was studied under the influence of a mixture of breath gases. Gas-sensitive sensors based on TCNQ compounds are characterized by a complex response curve with two extrema. Since the temporal variation in electrical conductivity of the sensor correlates well with the dependence of its resistance on the energy of the adsorbed components of the gas mixture, the resulting response curves of point-contact sensors can be called spectral profiles of a complex gas mixture. It is possible to differentiate among the various states of human body caused by the H. pylori bacterium by using spectral profiles of the gas exhaled by different patients. As a result, the developed sensors were shown to be an effective tool for analyzing breath gas exhaled in real time mode. They demonstrated a high sensitivity and selectivity to the products of activity of different H. pylori strains. Conclusions: It was shown that the products of metabolism of carcinogenic H. pylori strains had a dominant influence on electrical conductivity of the sensor and thus shaped the behavior of the features on sensor response curves. As a result, it is possible to differentiate H. pylori strains with respect to their carcinogenic potential using point-contact sensors based on TCNQ compounds. Thus, an effective portable tool was created in this work for the first time to develop innovative screening technologies for non-invasive diagnosis of human body conditions characterized by gastroduodenal pathology and to distinguish carcinogenic strains of H. pylori from tolerant ones.

Solid‐State Bioprocessing with Cordyceps militaris Enhanced Antioxidant Activity and DNA Damage Protection of Red Beans (Phaseolus angularis)

In this study, red beans were bioprocessed by using a novel solid‐state fermentation (SSF) with an edible and medical filamentous fungus Cordyceps militaris. The effect of SSF on the total phenolic content (TPC), antioxidant activity, and DNA damage protection of red beans was determined. Furthermore, solvents with different polarities (80% methanol, 80% ethanol, 80% acetone, and deionized water) were used to extract antioxidant compounds from the red bean samples. The results indicated that SSF significantly enhanced TPC, 2,2‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonic acid) diammonium salt radical cation scavenging activity, reducing power, and chelating ability of red beans. Furthermore, this study also demonstrated that fermented red beans exhibited greater protection against oxidative DNA damage than nonfermented red beans. Besides, the water extract of fermented red beans showed the highest TPC, antioxidant activity, and DNA damage protection among the various extracts examined. For the specific phenolics profile, HPLC analysis was performed, which showed that gallic acid, chlorogenic acid, p‐hydroxybenzoic acid, syringic acid, ferulic acid, daidzein, quercetin, and genistein of red beans were increased during SSF. There was a positive correlation among phenolic compounds, antioxidant activity, and DNA damage protection. Thus, this study demonstrated that SSF with C. militaris is an effective method for the enhancement of phenolic compounds, antioxidant activity, and DNA damage protection of red beans.

Triarylmethyl Radical: EPR Signal to Noise at Frequencies between 250 MHz and 1.5 GHz and Dependence of Relaxation on Radical and Salt Concentration and on Frequency.

In vivo oximetry by pulsed electron paramagnetic resonance is based on measurements of changes in electron spin relaxation rates of probe molecules, such as the triarylmethyl radicals. A series of experiments was performed at frequencies between 250 MHz and 1.5 GHz to assist in the selection of an optimum frequency for oximetry. Electron spin relaxation rates for the triarylmethyl radical OX063 as a function of radical concentration, salt concentration, and resonance frequency were measured by electron spin echo 2-pulse decay and 3-pulse inversion recovery in the frequency range of 250 MHz-1.5 GHz. At constant OX063 concentration, 1/T1 decreases with increasing frequency because the tumbling dependent processes that dominate relaxation at 250 MHz are less effective at higher frequency. 1/T2 also decreases with increasing frequency because 1/T1 is a significant contribution to 1/T2 for trityl radicals in fluid solution. 1/T2-1/T1, the incomplete motional averaging contribution to 1/T2, increases with increasing frequency. At constant frequency, relaxation rates increase with increasing radical concentration due to contributions from collisions that are more effective for 1/T2 than 1/T1. The collisional contribution to relaxation increases as the concentration of counter-ions in solution increases, which is attributed to interactions of cations with the negatively charged radicals that decrease repulsion between trityl radicals. The Signal-to-Noise ratio (S/N) of field-swept echo-detected spectra of OX063 were measured in the frequency range of 400 MHz-1 GHz. S/N values, normalized by √Q, increase as frequency increases. Adding salt to the radical solution decreased S/N because salt lowers the resonator Q. Changing the temperature from 19 to 37 °C caused little change in S/N at 700 MHz. Both slower relaxation rates and higher S/N at higher frequencies are advantageous for oximetry. The potential disadvantage of higher frequencies is the decreased depth of penetration into tissue.