Redox Mechanisms of Nodularin and Chemically Degraded Nodularin

Santos, Paulina V. F.; Lopes, Ilanna C.; Diculescu, Victor C.; Araújo, Mário César Ugulino de; Oliveira-Brett, Ana Maria

doi:10.1002/elan.201100246

Cited by 7 publications

(6 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Due to their high sensitivity, voltammetric methods have been successfully used for the detection and determination of various pharmaceutical and biological compounds and their metabolites. Moreover, the investigation of the redox behaviour of biologically relevant compounds by means of electrochemical techniques has the potential for providing valuable insights into the redox reactions of these molecules [19][20][21][22][23].…”

Section: Here Schemementioning

confidence: 99%

Temozolomide chemical degradation to 5-aminoimidazole-4-carboxamide – Electrochemical study

Lopes

Oliveira

Oliveira-Brett

2013

Journal of Electroanalytical Chemistry

Self Cite

View full text Add to dashboard Cite

The evaluation of the chemical degradation of temozolomide (TMZ), a potential anticancer drug, to its major metabolite 5-aminoimidazole-4-carboxamide (AIC), in aqueous solution with different pH values, was investigated at a glassy carbon electrode using cyclic and differential pulse voltammetry, and UV-Vis spectrophotometry. TMZ was incubated in aqueous solution, for different periods of time, and the changes in TMZ electrochemistry behaviour detected. The TMZ reduction is a pH-dependent irreversible process on the tetrazinone ring causing its irreversible breakdown. TMZ oxidation is a pH-dependent irreversible process that occurs in two consecutive charge transfer reactions. TMZ chemical degradation was electrochemically detected by the increase of the TMZ anodic peak current and the disappearance of the TMZ cathodic peak. The rate of chemical degradation increases with increasing pH and the mechanism corresponds to TMZ chemical degradation to AIC. The electrochemical behaviour of AIC over a wide pH range, was also investigated using cyclic, differential pulse and square wave voltammetry, AIC oxidation is an irreversible, diffusion-controlled process, pH-dependent up to a pH close to the pK a , and occurs in two consecutive charge transfer reactions, with the formation of two reversible redox products. A mechanism for AIC oxidation is proposed.

show abstract

Section: Here Schemementioning

confidence: 99%

Temozolomide chemical degradation to 5-aminoimidazole-4-carboxamide – Electrochemical study

Lopes

Oliveira

Oliveira-Brett

2013

Journal of Electroanalytical Chemistry

Self Cite

View full text Add to dashboard Cite

show abstract

“…NOD underwent chemical degradation in buffer with increasing incubation time [31], the NOD oxidation peak decreased in a time dependent manner and cdNOD occurred. The mechanism proposed for this process suggested the separation of the Adda side chain from the peptide ring structure giving rise to electroactive degradation products and a non-electroactive one formed by the NOD remaining peptide ring structure [31,32].…”

Section: Electrochemical Behaviour Of Nodmentioning

confidence: 99%

“…The mechanism proposed for this process suggested the separation of the Adda side chain from the peptide ring structure giving rise to electroactive degradation products and a non-electroactive one formed by the NOD remaining peptide ring structure [31,32].…”

Section: Electrochemical Behaviour Of Nodmentioning

confidence: 99%

“…A mechanism proposed for the chemical degradation after incubation in aqueous acidic buffer solutions consists in the separation of the Adda side chain from the peptide ring structure giving rise to an electroactive degradation product [31,32] and a non-electroactive degradation product formed by the MC-LR remaining peptide ring structure.…”

Section: Electrochemical Behaviour Of Mc-lrmentioning

confidence: 99%

See 1 more Smart Citation

DNA – Cyanobacterial Hepatotoxins Microcystin‐LR and Nodularin Interaction: Electrochemical Evaluation

et al. 2012

Self Cite

View full text Add to dashboard Cite

Microcystin-LR (MC-LR) and nodularin (NOD), two potent cyanotoxins with strong hepatotoxic, genotoxic and carcinogenic potential have been associated with the induction of deoxyribonucleic acid (DNA) damage in vitro and in vivo. Electrochemical studies were performed to understand the DNA interaction mechanisms with MC-LR and NOD using a dsDNA-electrochemical biosensor and incubated solutions. The decrease of the dsDNA oxidation peaks with increasing incubation time due to aggregation of DNA strands and the liberation of adenine free residues, causing the occurrence of DNA abasic sites, was observed, which may introduce mutations in the dsDNA during the replication process.

show abstract

“…In EAOPs, non-active anodes with high O 2 -overpotential (potential for O 2 development) such as borondoped diamond anodes (BDD) are usually employed. The higher the O 2 -overpotential, the weaker is the physisorption of OH to the anode surface, which, in turn, leads to higher OH availability in the solution[90].See formulas 40 -44 in the supplementary les section.Where M( OH) means OH is physisorbed to the anode surface M. Electrochemical oxidation of MC, NOD and CYN has been investigated with different electrodes and treatment parameters[120,[128][129][130][131]. One of the most in uential factors in terms of degradation effectiveness and operating costs are the electrodes used in EAOPs.…”

mentioning

confidence: 99%

Advanced oxidation processes for the removal of cyanobacterial toxins from drinking water

Schneider

Bláha

2020

Preprint

View full text Add to dashboard Cite

Drinking water production faces many different challenges with one of them being naturally produced cyanobacterial toxins. Since pollutants become more abundant and persistent today, conventional water treatment is often no longer sufficient to provide adequate removal. Amongst other emerging technologies, advanced oxidation processes (AOPs) have a great potential to appropriately tackle this issue. This review addresses the economic and health risks posed by cyanotoxins and discusses their removal from drinking water by AOPs. The current state of knowledge on AOPs and their application for cyanotoxin degradation is synthesized to provide an overview on available techniques and effects of water quality, toxin- and technique-specific parameters on their degradation efficacy. The different AOPs are compared based on their efficiency and applicability, considering economic, practical and environmental aspects and their potential to generate toxic disinfection byproducts. For future research, more relevant studies to include the degradation of less explored cyanotoxins, toxin mixtures in actual surface water, assessment of residual toxicity and scale-up are recommended. Since actual surface water most likely contains more than just cyanotoxins, a multi-barrier approach consisting of a series of different physical, biological and chemical – especially oxidative – treatment steps is inevitable to ensure safe and high quality drinking water.

show abstract

Redox Mechanisms of Nodularin and Chemically Degraded Nodularin

Cited by 7 publications

References 24 publications

Temozolomide chemical degradation to 5-aminoimidazole-4-carboxamide – Electrochemical study

Temozolomide chemical degradation to 5-aminoimidazole-4-carboxamide – Electrochemical study

DNA – Cyanobacterial Hepatotoxins Microcystin‐LR and Nodularin Interaction: Electrochemical Evaluation

Advanced oxidation processes for the removal of cyanobacterial toxins from drinking water

Contact Info

Product

Resources

About