Kinetics and electrochemical studies on superoxide

Mohammad, Mahboob; Khan, Ayan; Subhani, M. S.; Bibi, Nazia; Ahmad, Safeer; Saleemi, Saba

doi:10.1163/156856701300356473

Cited by 41 publications

(45 citation statements)

References 7 publications

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“…The cyclic voltammogram of super oxide radical showed one electron reversible process (Figure 1), having well developed and well resolved oxidation and reduction peaks with the peak separation (∆E p ) value of 66 mV, well in agreement with the reported data (Moure et al 2001). It is worth mentioning that the stability of superoxide radical in aqueous medium is quite low because of the high reactivity of the radical with water as discussed elsewhere (Mohammad et al 2001).…”

Section: Voltammetric Behaviour Of Super Oxide Anion Radicalsupporting

confidence: 87%

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Antioxidant activity coefficient, mechanism, and kinetics of different derivatives of flavones and flavanones towards superoxide radical

Ahmed¹,

Shakeel²

2012

Czech J. Food Sci.

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Ahmed S., Shakeel F. (2012). Antioxidant activity coefficient, mechanism, and kinetics of different derivatives of flavones and flavanones towards superoxide radical. Czech J. Food Sci., 30: 153-163.A systematic investigation of the electrochemically generated superoxide radical (O 2•-) has been conducted in the presence of some flavonoids. Cyclic voltammetry was used to generate O 2 •-by reducing the molecular oxygen in DMSO at room temperature. The scavenging of the radical was monitored by the decrease in anodic or/and cathodic currents while linearly increasing the concentration of the flavonoid. The strength of interaction was quantified in terms of the binding constant (K b ) values ranging from 1 × 10 2 and 5 × 10 3 M -1 . The antioxidant activity coefficient (K ao ) was calculated from the linear part of the plot of 'current decrease vs. flavonoid concentration' . Radical scavenging mechanism of the antioxidant was proposed and discussed in terms of the structure activity relationship. Nicholson-Shain method was employed to estimate the bimolecular homogeneous kinetics and on this basis control use of antioxidant is pointed out.

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Section: Voltammetric Behaviour Of Super Oxide Anion Radicalsupporting

confidence: 87%

“…hydroxyl radicals. Super oxide radical is toxic in nature and has the ability to react with different organic compounds due to its redox and paramagnetic nature (Mohammad et al 2001).…”

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confidence: 99%

Antioxidant activity coefficient, mechanism, and kinetics of different derivatives of flavones and flavanones towards superoxide radical

Ahmed¹,

Shakeel²

2012

Czech J. Food Sci.

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“…Superoxide anion (free radical with the chemical formula O 2 •‐ ) is one of the most dangerous radicals of oxygen regarding oxidative stress since it has a relatively long half‐life (about 260 ms for 1 μM O 2 •‐ at pH = 6.5) and thus can move long distances within the cytosol, acting also as an initiator to form other radicals such as hydroxyl radicals, through the Haber‐Weiss reaction, or peroxynitrite, after reacting with nitric oxide, NO . The superoxide anion has also the ability to react with different organic compounds due to its redox and paramagnetic nature …”

Section: Introductionmentioning

confidence: 99%

Systematic Derivatization of Curcumin and its Effect on Antioxidant Capacity and Action Mechanism. Cyclic Voltammetry and DFT as Tools of Analysis

et al. 2016

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Eight curcumin derivatives were synthesized by esterification of its phenol groups with first and second generation polyester dendrons (dendronization) or glutaric anhydride (glutarization), in a systematic scheme where mono and disubstitutions were carried out. The dendronization of curcumin (CUR) affects the fragmentation patterns in mass spectra, particularly for the disubstituted OH-terminated second generation derivative (labeled as 2C2), undergoing the cleavage of one of the aromatic rings. This fact may be related to the antioxidant capacity of 2C2, evaluated following its reaction with superoxide (O 2 *-) by cyclic voltammetry (CV). As opposed to CUR and the rest of its derivatives that react with O 2 *via proton transfer reactions, 2C2 reacts with O 2 *mainly by hydrogen atom transfer. 2C2 radical scavenging activity versus O 2 *is higher than the one observed for CUR. From DFT calculations, independently of the substitution on CUR, the frontier molecular orbitals remain nearly unaltered as compared to CUR. On the other hand, when CUR is dendronized, the electric dipole moment notably changes as a function of the nature of the terminal groups.

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“…techniques. One of the techniques mentioned previously, the electrochemical technique has been extensively used to study the reactivity of anion radicals and dianions of nitro aromatics and quinones . Linear scan/cyclic voltammetry technique has been increasingly used in studying hydrogen‐bonding phenomenon .…”

Section: Introductionmentioning

confidence: 99%

“…Anion radicals and dianions, in general, can form inter‐molecular and intra‐molecular hydrogen bonding . Hence, anions and dianions of dinitro aromatics could easily undergo hydrogen bonding/protonation .…”

Section: Introductionmentioning

confidence: 99%

The equilibrium and kinetics of intermolecular hydrogen bonding in nitroarene anion radical–alcohol system: 1,3‐dinitro‐benzene anion radical – R–OH (R═CH₃–, C₂H₅–, (CH₃)₂ CH–)

Mohammad

Rauf

et al. 2012

J of Physical Organic Chem

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To explore the possibility of hydrogen bonding of a stable anion radical with DNAcomponent sugar, hormones, steroid, and so on (through hydroxyl group), as a first step, the possibility of hydrogen bonding of 1,3-dinitrobenzene anion radical (1,3-DNB À• ) with aliphatic alcohols was studied. It was found that 1,3-DNB À• anion radical undergoes hydrogen bonding with alcohols: methanol, ethanol, and 2-proponal. The hydrogen-bonding equilibrium constant K eq and the (hydrogen-bonding) rate constants k 2 were evaluated through the use of linear scan and cyclic voltammetry theory and techniques. The K eq was found to be in the range of 1.4-6.0 M À1 , whereas the rate constants k 2 were found to be in the range of 1.5-3.6 M À1 s À1 , depending upon the hydrogen-bonding agent and the equation used for the calculation of the rate constants. The hydrogen-bonding number n was found to be around 0.5 or 1.0. The implication of this study in, for example, the replication of DNA, the prevention of the formation of super oxide, and so on is discussed.

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Kinetics and electrochemical studies on superoxide

Cited by 41 publications

References 7 publications

Antioxidant activity coefficient, mechanism, and kinetics of different derivatives of flavones and flavanones towards superoxide radical

Antioxidant activity coefficient, mechanism, and kinetics of different derivatives of flavones and flavanones towards superoxide radical

Systematic Derivatization of Curcumin and its Effect on Antioxidant Capacity and Action Mechanism. Cyclic Voltammetry and DFT as Tools of Analysis

The equilibrium and kinetics of intermolecular hydrogen bonding in nitroarene anion radical–alcohol system: 1,3‐dinitro‐benzene anion radical – R–OH (R═CH₃–, C₂H₅–, (CH₃)₂ CH–)

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Kinetics and electrochemical studies on superoxide

Cited by 41 publications

References 7 publications

Antioxidant activity coefficient, mechanism, and kinetics of different derivatives of flavones and flavanones towards superoxide radical

Antioxidant activity coefficient, mechanism, and kinetics of different derivatives of flavones and flavanones towards superoxide radical

Systematic Derivatization of Curcumin and its Effect on Antioxidant Capacity and Action Mechanism. Cyclic Voltammetry and DFT as Tools of Analysis

The equilibrium and kinetics of intermolecular hydrogen bonding in nitroarene anion radical–alcohol system: 1,3‐dinitro‐benzene anion radical – R–OH (R═CH3–, C2H5–, (CH3)2 CH–)

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The equilibrium and kinetics of intermolecular hydrogen bonding in nitroarene anion radical–alcohol system: 1,3‐dinitro‐benzene anion radical – R–OH (R═CH₃–, C₂H₅–, (CH₃)₂ CH–)