Dataset Information

Kinetics and Mechanism of the Antioxidant Activities of C. olitorius and V. amygdalina by Spectrophotometric and DFT Methods.

ABSTRACT: The kinetics and mechanism of the antioxidant activities of the methanolic extract of the leaves of two vegetables [Corchorus olitorius (C. olitorius) and Vernonia amygdalina (V. amygdalina)] have been studied using experimental and theoretical approaches. The kinetics (second order and pseudo-first order) of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities of the leaf extracts at varying times (30-90 min) were determined using the UV-visible spectrophotometry method at ?max = 517 nm, whereas the mechanism was studied by density functional theory at two levels of functionals (B3LYP and LC-?PBE) using bond dissociation enthalpy and adiabatic ionization potential values. Molecular properties such as the highest occupied molecular orbital, lowest unoccupied molecular orbital, electronegativity (?), electrophilicity (?), hardness (?), and softness (S) of the predominant phenolic antioxidants were also compared. The second-order kinetics is favored by both plants rather than pseudo-first order; however, V. amygdalina with a second-order rate constant k 2 of 0.0152 (mM)-1 min-1 is faster in scavenging DPPH radicals than C. olitorius with a k 2 value of 0.0093 (mM)-1min-1. Chlorogenic acid and luteolin-7-O-?-glucuronide, which are the most abundant phenolic acid antioxidant in C. olitorius and V. amygdalina, both preferably scavenge the DPPH radical via a hydrogen atom transfer mechanism. This is evident from their lower bond dissociation enthalpy values than the adiabatic ionization potential values. Successful molecular docking of these phenolic compounds indicates that both compounds form favorable interactions with the therapeutic target, xanthine oxidase.

SUBMITTER: Yusuff OK

PROVIDER: S-EPMC6714516 | biostudies-literature | 2019 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Kinetics and Mechanism of the Antioxidant Activities of C. olitorius and V. amygdalina by Spectrophotometric and DFT Methods.

Yusuff Olaniyi K OK Abdul Raheem Modinah Adenike O MAO Mukadam Abdulrahman A AA Sulaimon Ridwan Oladayo RO

ACS omega 20190816 9

The kinetics and mechanism of the antioxidant activities of the methanolic extract of the leaves of two vegetables [Corchorus olitorius (C. olitorius) and Vernonia amygdalina (V. amygdalina)] have been studied using experimental and theoretical approaches. The kinetics (second order and pseudo-first order) of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities of the leaf extracts at varying times (30-90 min) were determined using the UV-visible spe ...[more]

PMID: 31497684

Similar Datasets

Project description:The analysis of antioxidants in different foodstuffs has become an active area of research, which has led to many recently developed antioxidant assays. Many antioxidants exhibit inherent electroactivity, and, therefore, the use of electrochemical methods could be a viable approach for evaluating the overall antioxidant activity of a matrix of nutraceuticals without the need for adding reactive species. Green tea is believed to be a healthy beverage due to a number of therapeutic benefits. Catechin, one of its constituents, is an important antioxidant and possesses free radical scavenging abilities. The present paper describes the electrochemical properties of three screen-printed electrodes (SPEs), the first one based on carbon nanotubes (CNTs), the second one based on gold nanoparticles (GNPs) and the third one based on carbon nanotubes and gold nanoparticles (CNTs-GNPs). All three electrodes were modified with the laccase (Lac) enzyme, using glutaraldehyde as a cross-linking agent between the amino groups on the laccase and aldehyde groups of the reticulation agent. As this enzyme is a thermostable catalyst, the performance of the biosensors has been greatly improved. Electro-oxidative properties of catechin were investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV), and these demonstrated that the association of CNTs with GNPs significantly improved the sensitivity and selectivity of the biosensor. The corresponding limit of detection (LOD) was estimated to be 5.6 × 10-8 M catechin at the CNT-Lac/SPE, 1.3 × 10-7 M at the GNP-Lac/SPE and 4.9 × 10-8 M at the CNT-GNP-Lac/SPE. The biosensors were subjected to nutraceutical formulations containing green tea in order to study their catechin content, using CNT-GNP-Lac/SPE, through DPV. Using a paired t-test, the catechin content estimated was in agreement with the manufacturer's specification. In addition, the relationship between the CNT-GNP-Lac/SPE response at a specific potential and the antioxidant activity of nutraceuticals, as determined by conventional spectrophotometric methods (DPPH, galvinoxyl and ABTS), is discussed in the context of developing a fast biosensor for the relative antioxidant activity quantification.

Dataset Information

Kinetics and Mechanism of the Antioxidant Activities of C. olitorius and V. amygdalina by Spectrophotometric and DFT Methods.

Publications

Kinetics and Mechanism of the Antioxidant Activities of <i>C. olitorius</i> and <i>V. amygdalina</i> by Spectrophotometric and DFT Methods.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets