Quercetin may act as a cytotoxic prooxidant after its metabolic activation to semiquinone and quinoidal product

Metodiewa, Diana; Jaiswal, Anil K.; Čėnas, Narimantas; Dičkancaitè, Egle; Segura‐Aguilar, Juan

doi:10.1016/s0891-5849(98)00167-1

Cited by 483 publications

(333 citation statements)

References 28 publications

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“…These reactions were described previously and have been taken into account to explain the antioxidant and pro-oxidant activities of quercetin in pharmacological researches. 24,25 According to Figure 10, the oxidation of quercetin I involving the participation of one-electron and one-proton leads to the formation of the ortho-semiquinone II, which can be further oxidized in a one-electron and one-proton forming the para-quinone methide IV. The intermediate IV can subsequently turn into one of its analogous III, V or VI through tautomerization.…”

Section: Temperature (~ 2 O C) After a Given Period Of Time (96 H)mentioning

confidence: 99%

Electrochemical oxidation of quercetin in hydro-alcoholic solution

Timbola¹,

Souza²,

Giacomelli³

et al. 2006

J. Braz. Chem. Soc.

135

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O comportamento eletroquímico da quercetina em meio hidro-alcoólico foi estudado na faixa de pH 2,2-9,2 aplicando-se as técnicas voltametria cíclica, eletrólise com potencial controlado e espectroscopia UV-Vis. Voltamogramas cíclicos para a quercetina mostraram três picos de oxidação e um pico de redução dependente das condições experimentais. Um processo de oxidação envolvendo dois prótons e dois elétrons no primeiro pico conduziu à formação da orto-quinona correspondente, a qual é uma espécie eletroquimicamente ativa e instável, como evidenciado pela dependência do perfil dos voltamogramas cíclicos com a velocidade de variação de potencial, em concordância com um mecanismo do tipo eletroquímico-químico (EC). Eletrólises com potencial controlado geraram três produtos caracterizados por espectroscopia UV-Vis. Um esquema reacional envolvendo as etapas eletroquímica e química foi proposto para a eletro-oxidação da quercetina em solução hidro-alcoólica, com base em dados obtidos da literatura e em evidências experimentais.The electrochemistry of quercetin hydro-alcoholic solutions of pH 2.2 to 9.2 was studied by cyclic voltammetry, controlled-potential electrolysis and UV-Vis spectroscopy. Cyclic voltammograms for quercetin showed three oxidation peaks and one reduction peak depending on the experimental conditions. The two-electron two-proton oxidation process at the first peak led to the formation of the corresponding ortho-quinone, which is an electrochemically active and unstable species, as evidenced by the dependence of the cyclic voltammogram profile on the applied scan rate, in agreement with the EC mechanism. Controlled-potential electrolysis yielded three products as characterized by UV-Vis spectroscopy. A reaction scheme comprising electrochemical and chemical steps was proposed for the electro-oxidation of the quercetin in hydro-alcoholic solutions on basis of experimental evidences obtained in this work and elsewhere.

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Section: Temperature (~ 2 O C) After a Given Period Of Time (96 H)mentioning

confidence: 99%

Electrochemical oxidation of quercetin in hydro-alcoholic solution

Timbola¹,

Souza²,

Giacomelli³

et al. 2006

J. Braz. Chem. Soc.

135

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“…Based on its anti-and prooxidant activities, two anticancer mechanisms of quercetin have been proposed. First, quercetin can scavenge reactive oxygen species (ROS) as an antioxidant and thereby reduce DNA damage (6,7). In addition, quercetin has been shown to affect the cytochrome P450 (CYP) system, which is one of the main sources of ROS generation in the cell (8,9).…”

Section: Introductionmentioning

confidence: 99%

Quercetin acts as an antioxidant and downregulates CYP1A1 and CYP1B1 against DMBA-induced oxidative stress in mice

Choi

Kim

2012

Oncol Rep

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Abstract. We investigated the effects of quercetin on 7,12-dimethylbenz(a)anthracene (DMBA)-induced oxidative stress and the expression of CYP1A1 and CYP1B1 in mice. Quercetin was administered orally to mice at 100 or 250 mg/kg BW for 18 days, after which DMBA (34 mg/kg BW) was administered intragastrically twice. Quercetin showed side effects such as increased aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in DMBA-untreated mice. Also, quercetin induced AST and ALT in DMBA-treated, although this was not significantly different from levels in DMBA-treated controls. The thiobarbituric acid reactive substances (TBARS) value showed a tendency to decrease following quercetin treatment; these decreases were significantly greater in the DMBA-treated compared to the untreated groups. Also, catalase and superoxide dismutase (SOD) activities as well as their mRNA expression were increased by quercetin; this increase was more pronounced in DMBA-treated compared to untreated mice. DMBA induced CYP1 activity as well as expression of CYP1A1 and CYP1B1. Each of these effects was significantly reduced by quercetin; however, this reduction was observed for CYP1A1 at only the higher dose and for CYP1B1 at both doses. These data suggest that quercetin shows antioxidant activity against DMBA-induced oxidative stress. Moreover, its regulation of CYP1A1 and CYP1B1 suggests the potential of quercetin as an anticancer supplement.

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“…Naturally occurring quinones (such as juglone, vitamin K, plumbagin) bearing α,β-unsaturated carbonyl moieties represent typical xenohormetics (Shibayama-Imazu et al 2006;Przybysz et al 2009;Son et al 2010). Furthermore, flavonoids might represent precursors of xenohormetic molecules and undergo conversion by oxidative metabolism which involves a two-electron auto-oxidation to an electrophilic quinone-type molecule (Metodiewa et al 1999;Awad et al 2000;Bast and Haenen 2002). In this regard, quercetin, as a precursor of ortho-quinone molecule, showed a range of beneficial effects on organisms including life extension of yeasts and nematodes, chemopreventive effects, enhancement of cognitive functions and protection of immune system in aged animals (Chondrogianni et al 2010;Vargas and Burd 2010;Pietsch et al 2011;Si and Liu 2014).…”

Section: Ii) Protein Carbonyls Intensitymentioning

confidence: 99%

Protection or cytotoxicity mediated by a novel quinonoid-polyphenol compound?

Milackova¹,

Račková²,

Májeková³

et al. 2015

gpb

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Abstract. Many natural and synthetic quinones and naphthoquinones possess a variety of beneficial pharmacological properties. In plants, the cytotoxic properties of quinones serve in their defensive roles against invading bacteria, fungi and parasites. In this regard many quinones as well as polyphenols, exerting generally toxicity at high dosages, are able to induce favorable hormetic responses at a low dosage. The novel chloronaphthoquinone derivative of quercetin (CHNQ) showed a profound cytotoxicity followed by enhancement of intracellular generation of oxidants in human neonatal B-HNF-3 fibroblasts. Its synthetic precursors, quercetin and 2-chloro-3-hydroxy-[1,4]naphthoquinone, failed to induce these effects, and paradoxically, only CHNQ at a low concetration provided partial protection of the cells against oxidative challenge. Thus, the novel quinonoid-polyphenol CHNQ might have a merit in the search for new prospective agents in prevention and management of ageing and ageing-related pathologies.

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Quercetin may act as a cytotoxic prooxidant after its metabolic activation to semiquinone and quinoidal product

Cited by 483 publications

References 28 publications

Electrochemical oxidation of quercetin in hydro-alcoholic solution

Electrochemical oxidation of quercetin in hydro-alcoholic solution

Quercetin acts as an antioxidant and downregulates CYP1A1 and CYP1B1 against DMBA-induced oxidative stress in mice

Protection or cytotoxicity mediated by a novel quinonoid-polyphenol compound?

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Quercetin may act as a cytotoxic prooxidant after its metabolic activation to semiquinone and quinoidal product

Cited by 483 publications

References 28 publications

Electrochemical oxidation of quercetin in hydro-alcoholic solution

Electrochemical oxidation of quercetin in hydro-alcoholic solution

Quercetin acts as an antioxidant and downregulates CYP1A1 and CYP1B1 against DMBA-induced oxidative stress in mice

Protection or cytotoxicity mediated by a novel quinonoid-polyphenol compound?

Contact Info

Product

Resources

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Protection or cytotoxicity mediated by a novel quinonoid-polyphenol compound?