The isoflavonoid genistein was found to be a better antioxidant than the isomeric flavonoid apigenin in phosphatidyl liposomes at pH 7.4. higher antioxidation activity of compared with is agreement its lower oxidation potential (0.73 vs 0.86 V as determined by cyclic voltammetry aqueous solution pH= 7.4), dissociation enthalpy (87.03 87.88 kcal mol−1 calculated for more reducing 4′-hydroxyl group), and radical scavenging capacity TEAC assay. On basis quantum mechanical calculations...

Nanostructured KxNayMnFe(CN)6 (x + y ≤ 2) has been synthesized via a facile co-precipitation method. As cathode, KNMF-3 presents highly reversible capacity of 133.3 mA h g-1 at 20 as well an excellent rate 92.0 600 g-1. This material could be good candidate cathode for sodium-ion batteries.

Carbon materials with a novel structure have been considered to be potential anodes for sodium ion batteries (SIBs).

The 4‘-hydroxyl group of puerarin, a C-glycoside the isoflavonoid daidzein, was shown, using 2,2‘-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical cation and stopped-flow spectroscopy by comparison with 7-propylpuerarin (A ring derivative) 4‘-propylpuerarin (B derivative), to be more efficient scavenger as compared 7-hydroxyl factor 2, difference increasing upon deprotonation. in scavenging agreed oxidation potentials (cyclic voltammetry acetonitrile, 0.1 M Bu4NBF4 at 25 °C): E/mV =...

Kinetics studies provide mechanistic insight regarding the formation of dinitrosyl iron complexes (DNICs) now viewed as playing important roles in mammalian chemical biology ubiquitous bioregulator nitric oxide (NO). Reactions deaerated aqueous solutions containing FeSO4, cysteine (CysSH), and NO demonstrate that both rates outcomes are markedly pH dependent. The dinuclear DNIC Fe2(μ-CysS)2(NO)4, a Roussin's red salt ester (Cys-RSE), is formed at 5.0 well lower concentrations neutral...

Abstract Carbonaceous materials are one of the most promising anode for sodium‐ion batteries, because their abundance, stability, and safe usage. However, practical application carbon is hindered by poor specific capacity low initial Coulombic efficiency. The design porous structure doping with heteroatoms two simple effective methods to promote sodium storage performance. Herein, N, P co‐doped fabricated using renewable biodegradable gelatin as nitrogen resource, phosphoric acid phosphorus...

Isoflavone daidzein (D, pKa1 = 7.47 ± 0.02 and pKa2 9.65 0.07) was, through a study of the parent compound its three methyl anisol derivatives 7-methyldaidzein (7-Me-D, pKa 9.89 0.05), 4′-methyldaidzein (4′-Me-D, 7.43 0.03), 7,4′-dimethyldaidzein (7,4′-diMe-D), found to retard lipid oxidation in liposomal membranes two mechanisms: (i) radical scavenging for which 4′-OH was more effective than 7-OH group agreement with potentials: 0.69 V 0.92 versus Ag/AgCl acidic solution 0.44 4′-O− 0.49...

The lipophilic flavonoid glycoside baicalin from the traditional oriental herb Scutellaria baicalensis Georgi (logP = 1.27, pK(a1) 7.6, pK(a2) 10.1 as determined at 25 degrees C in 0.1 M NaCl) is found to be reducing (0.39 V vs NHE, reversible two-electron oxidation by CV pH 7.4) other catechol flavonoids but a poor radical scavenger (TEAC 1.12, and antioxidant against free initiated lipid liposomes. However, this compound able regenerate beta-carotene (beta-Car) beta-Car(*+) with...

Hydroxyl radical reacts readily with β-carotene following submicrosecond laser photolysis of N-hydroxypyridine-2(1H)-thione (N-HPT) as a "photo-Fenton" reagent generating hydroxyl and thiyl radicals in acetonitrile:tetrahydrofuran (4:1, v/v) solution. On the basis spectral evidence, supported by kinetic considerations thermodynamic calculations, short-lived transient species, detected time-resolved absorption spectroscopy an maximum at ∼750 nm lifetime ∼150 ns 25 °C under anaerobic...

Electron transfer to radical cations of β-carotene, zeaxanthin, canthaxanthin, and astaxanthin from each the three acid/base forms diphenolic isoflavonoid daidzein its C-glycoside puerarin, as studied by laser flash photolysis in homogeneous methanol/chloroform (1/9) solution, was found depend on carotenoid structures more significantly deprotonation degree isoflavonoids. None reacted with neutral isoflavonoids while monoanionic dianionic regenerated oxidized carotenoid. β-carotene cation...

The nitrogen-doped 3D bubble-like porous graphene (N-3DPG) is a promising candidate for apllication in sodium ion batteries large-scale electrochemical energy storage.

Binding to bovine serum albumin (BSA) was found protect β-carotene (β-Car) dissolved in air-saturated phosphate buffer solution/tetrahydrofuran (9:1, v/v) efficiently against photobleaching resulting from laser flash excitation at 532 nm. From dependence of the relative yield upon BSA concentration, an association constant Ka = 4.67 × 10(5) L mol(-1) for β-Car binding determined 25 °C. Transient absorption spectroscopy confirmed less bleaching on microsecond time scale presence BSA, while...

Rosemary is one of the most promising, versatile, and studied natural preservatives. Carnosic acid (CA) carnosol (CARN), as primary active ingredients rosemary extracts, have little difference in structure, but their antioxidant activities vary significantly, depending on system studied. The underlying molecular mechanisms remain unclear. By means optical spectroscopies, stopped-flow, laser photolysis, density functional theory (DFT) calculations, we compared CA CARN between reaction...

In the reaction between trans-resveratrol (resveratrol) and hydroxyl radical, kinetic product control leads to a short-lived radical adduct with an absorption maximum at 420 nm lifetime of 0.21 ± 0.01 μs (anaerobic acetonitrile 25 °C) as shown by laser flash photolysis using N-hydroxypyridine-2(1H)-thione (N-HPT) "photo-Fenton" reagent. The transient spectra are in agreement density functional theory (DFT) calculations showing 442 or 422 for C2 C6 adducts, respectively, lowest energy...

Green tea polyphenols, (−)-epicatechin (EC), (−)-epigallocatechin (EGC), gallate (ECG), and (EGCG), all showed antioxidative effect in liposomes for lipid oxidation initiated the phase (antioxidant efficiency EC > EGCG ECG EGC) or aqueous (EC ≫ EGC ECG) as monitored by formation of conjugated dienes. For initiation phase, β-carotene, itself active an antioxidant, antagonism with polyphenols EGC). The Trolox equivalent antioxidant capacity (TEAC EC) correlates lowest phenol O–H bond...

Luteolin differs as a radical scavenger dramatically from apigenin in response to Cu(II) coordination despite minor structural difference. Coordination of increases the scavenging efficiency luteolin, especially at low pH, while decreases both and higher pH studied by ABTS•+ scavenging. forms 1:1 complex with binding 4-carbonyl 5-phenol for <6 3′,4′-catechol >6. Apigenin 1:2 independent coordinated 5-hydroxylyl. jump stopped-flow, translocates rate constants 11.1 ± 0.3 s–1 4,5 3′,4′ sites...

Antioxidant synergism (or antagonism) between plant (iso)flavonoids (daidzein, baicalein, and quercetin) or their glycosides (puerarin, baicalin, rutin) β-carotene in phosphatidylcholine liposomes (pH 7.4) with oxidation initiated thermally by the lipophilic free radical initiator 2,2'-azobis(2,4-dimethylvaleronitrile) (AMVN) followed formation of conjugated dienes did not depend simply on bond dissociation enthalpy (BDE) phenol O-H HOMO/LUMO energy gap based density functional theory (DFT)...

Tyrosinase, widely distributed in nature, is a copper-containing polyphenol oxidase involved the formation of melanin. Flavonoids are most often considered as tyrosinase inhibitors but have also been confirmed to be substrates. Four structure-related flavonoids including flavones (apigenin and luteolin) flavonols (kaempferol quercetin) found promote not inhibit browning induced by catalyzed oxidation both model systems mushrooms under aerobic conditions. A comparison with enzymatic...

Abstract The electronic environment and physicochemical property of carbon materials can be easily tailored modulated by heteroatom doping. Herein, we demonstrate that net‐like N, O, S triple‐doped microporous nanowires (NOS‐MCNs) as an anode designed to improve the electrochemical performance sodium ion batteries. Ammonium persulfate oxidant also provide a nitrogen sulfur source for S‐containing PPy. O atoms are introduced into skeleton with activation carbonization processes modify surface...

The C-40 xanthophylls zeaxanthin and astaxanthin were confirmed to form radical cations, Car.+, in the electron-accepting solvent chloroform by direct excitation using subpicosecond time-resolved absorption spectroscopy combination with spectroelectrochemical determination of near-infrared Car.+. For singlets, S2(1B(u+) state most likely S(x)(3A(g)-) directly eject electrons leading rapid formation Car.+ on a timescale approximately 100 fs; lowest-lying S1(2A(g)-) state, however, remains...

Genistein, but not daidzein, binds to copper(II) with a 1:2 stoichiometry in ethanol and 1:1 methanol, indicating chelation by the 5-phenol 4-keto group of isoflavonoid as demonstrated Jobs method UV-visible absorption spectroscopy. In ethanol, stability constants had value 1.12 × 1011 L2∙mol−2 for complex methanol 6.0 105 L∙mol−1 at 25 °C. Binding was detected water, confirmed an upper limit constant K = 5 mol−1 L calculated from difference solvation free energy between more polar water....

Zinc(II) enhances radical scavenging of the flavonoid kaempferol (Kaem) most significantly for 1:1 Zn(II)-Kaem complex in equilibrium with 1:2 both high affinity at 3-hydroxyl and 4-carboxyl coordination. In methanol/chloroform (7/3, v/v), reduces β-carotene cation, β-Car•+, a second-order rate constant, 1.88 × 108 L·mol–1·s–1, while Kaem are nonreactive, as determined by laser flash photolysis. ethanol, 2,2-diphenyl-1-picrylhydrazyl radical, DPPH•, 2.48 104 16 times 2 efficient complex,...

Regeneration of β-carotene from the radical cation by 4'-propylpuerarin anion (second-order rate constant=1.5×10(9) L mol(-1) s(-1) in methanol/chloroform=1:9 (v/v) solution at 25 °C as determined laser flash photolysis) was found to be marginally slower than regeneration 7-propylpuerarin (2.3×10(9) s(-1)), agreement with being more reducing (E'=0.56 V vs NHE) (E'=1.01 NHE). The potentials were calculated E°=1.12 and 1.44 (vs cyclic voltametry aqueous pKa=9.51 7.23 obtained previously for...