40479-76-3

Upstream product

• 147506-92-1 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl 
• 154-23-4 catechin 

Downstream Products

• 4670-05-7 neotheaflavin 

Relevant academic research and scientific papers

Kinetic Study of Flavonoid Reactions with Stable Radicals

The antiradical activities of some flavonols (kaempferol, quercetin, robinetin, quercetagetin, and myricetin), flavones (apigenin, baicalein, and luteolin), flavanones (naringenin and dihydroquercetin), and flavanols [(+)-catechin and (-)-epicatechin] wer

Lignocellulosic biomass-derived, graphene sheet-like porous activated carbon for electrochemical supercapacitor and catechin sensing

We synthesize graphene sheet-like porous activated carbon (GPAC) with a high specific surface area by using Bougainvillea spectabilis as a precursor with the assistance of a facile and reliable chemical activation method. The as-synthesized GPAC materials

Nonenzymatic Biomimetic Synthesis of Black Tea Pigment Theaflavins

Theaflavins are reddish-orange black tea pigments with a benzotropolone chromophore, and their various biological activities have been reported. Theaflavins are produced by oxidative coupling between catechol-type and pyrogallol-type catechins via bicyclo[3.2.1]octane-type intermediates. In this study, a new method for nonenzymatic biomimetic synthesis of theaflavins was developed using the DPPH radical as an oxidizing agent.

Oxidation of natural substances having glucoskeleton succinylisoflavone succinylisoflavone natural substance and having glucoskeleton decontamination strychinifolia and method of manufacturing

PROBLEM TO BE SOLVED: To provide a method for oxidizing a natural material having a flavonoid skeleton, and a method for dyeing hair using the oxidized material. SOLUTION: The natural material having a flavonoid skeleton such as (+)- catechin is oxi

Reactivity of dpph in the oxidation of catechol and catechin

A kinetic study of the reduction of pyrocatechol and catechin by dpph radical has been carried out in various ratios of CH 3OH/H2O mixed solvent at pH 5.5-7.5, μ = 0.10 M [(n-Bu)4N]ClO4, and T = 25°C. The rate constants of oxidation in aqueous solvent, kH2O, were obtained from the extrapolation of the linear plots of the specific rate constants k vs. % H 2O plots at each pH value. A linear relationship between k H2O and 1/[H+] was observed for both flavonoids with kH2O = k1Ka1/[H+], where K a1 was the first acid dissociation constant on the catechol ring and k1 is the rate constant of the oxidation of the mononegative species HX-. The values of k1 obtained from the slopes of the plots are (8.2 ± 0.2) × - 105 and (6.1 ± 0.1) × - 105 M-1 s-1 for pyrocatechol and catechin, respectively. The analysis of the reaction on the basis of Marcus theory for an outer-sphere electron transfer reaction yielded a value of 3.7 × - 103 M-1 s-1 for the self-exchange rate constant of dpph/dpphH couple.

Use of experimental design methodology to prepare Maillard reaction products from glucose and cysteine inhibitors of polyphenol oxidase from eggplant (Solanum melongena)

Polyphenol oxidase (PPO) from eggplant was extracted and partially purified by a two-step fractionation-precipitation using ammonium sulfate and phenylsepharose hydrophobic interaction chromatography. The eggplant PPO extract was characterized concerning

Superoxide Anion Generation via Electron-Transfer Oxidation of Catechin Dianion by Molecular Oxygen in an Aprotic Medium

Superoxide anion (O2.-) was generated via an electron-transfer oxydation of catechin dianion, which was produced in the reaction of catechin with two equivalents of methoxide anion, by molecular oxygen in acetonitrile. From the detailed spectro

Antioxidant properties of anthocyanins and tannins: A mechanistic investigation with catechin and the 3′,4′,7-trihydroxyflavylium ion

Plant polyphenols act as antioxidants mainly by trapping reactive oxygen species and by regenerating endogenous membrane-bound α-tocopherol (vitamin E). In both processes polyphenols are oxidized. Hence, knowledge of the oxidation mechanisms of polyphenols is important for an understanding of their antioxidant activity at the molecular level. This work focuses on anthocyanins (pigments) and flavanols (tannins), two important classes of polyphenols which are both relatively abundant in human diet. The oxidation of the 3′,4′,7-trihydroxyflavylium ion (1) and catechin (2), respectively taken as models for anthocyanins and tannins, has been investigated. From kinetic data and partial product analysis, the mechanisms for the reactions of 1 and 2 with sodium periodate and DPPH, a H atom-abstracting radical, are proposed. Both polyphenols are shown to form o-quinone intermediates upon H atom abstraction and subsequent radical disproportionation. In the case of 2, the quinone and a second molecule of antioxidant quickly couple to form dimers. By contrast, 1 is extensively degraded into coumarins by repeating sequences of oxidation-solvent addition, which consume several equivalents of oxidants. In aqueous solutions, 1 is typically a mixture of coloured and colourless forms. The latter (chalcones) are also shown to take part in the antioxidant activity.

NMR Analytical Approach to Clarify the Antioxidative Molecular Mechanism of Catechins Using 1,1-Diphenyl-2-picrylhydrazyl

Each tea catechin was reacted with 1,1-diphenyl-2-picrylhydrazyl (DPPH), and the reaction mixture was subjected to NMR analysis. The antioxidation mechanism of (+)-catechin [(+)-C] is considered to be due to the change of the B-ring to an o-quinone struct

ROLES OF o-QUINONES AND THEIR POLYMERS IN THE ENZYMIC BROWNING OF APPLES

Enzymic browning and the bleaching produced by the addition of ascorbic acid have been studied simultaneously in crushed apple tissue and in pure solutions of (+)-catechin and chlorogenic acid.Spectrophotocolorimetry was used to study crushed apple tissue