Evaluation and application of electroanalysis for the determination of antioxidants

The role of antioxidants in the prevention of neurodegenerative diseases has been well documented. The use of synthetic antioxidants has decreased due to the ssociation of these compounds with certain cancers. Thus, the search for novel natural antioxidants has gained much focus in research. Most co...

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Main Author: Ragubeer, Nasheen
Format: Others
Language:English
Published: Rhodes University 2007
Subjects:
Online Access:http://hdl.handle.net/10962/d1003981
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spelling ndltd-netd.ac.za-oai-union.ndltd.org-rhodes-vital-39222017-07-20T04:13:27ZEvaluation and application of electroanalysis for the determination of antioxidantsRagubeer, NasheenAntioxidantsNervous system -- DegenerationElectrochemical analysisMarine algaeNatural productsMarine metabolitesSargassumLegumesNuclear magnetic resonanceThe role of antioxidants in the prevention of neurodegenerative diseases has been well documented. The use of synthetic antioxidants has decreased due to the ssociation of these compounds with certain cancers. Thus, the search for novel natural antioxidants has gained much focus in research. Most common methods of determining antioxidant capacity are the radical generated assays and biological assays such as lipid peroxidation and the nitroblue tetrazolium assay. Electrochemical methods have been proposed for the determination of bio-active compounds such as antioxidants. The electrochemical methods of cyclic voltammetry and square wave voltammetry were evaluated for the determination of antioxidant capacity initially examining known antioxidants and then using plant extracts of Sutherlandia frutescens as a case study. The antioxidant properties determined by electrochemical methods were validated utilising the non-biological methods of the DPPH, TEAC, ferrozine and FC assay and biological pharmacological methods. The results indicated that Sutherlandia frutescens contains potent antioxidant compounds that are able to reduce lipid peroxidation. The electrochemical techniques of square wave voltammetry and cyclic voltammetry were applied for the screening of a large number of extracts of various algae for the detection of antioxidant compounds. The results indicated that electrochemistry can be used as a preliminary method for the rapid screening of a large number of crude samples for antioxidant compounds. Electrochemical methods were also evaluated as a method for guiding the isolation and purification of antioxidant metabolites in Sargassum elegans. Solvent partitioning and fractionation of the marine alga allowed for the purification of antioxidant compounds. At each step of purification electrochemical methods were utilized to determine which fractions contained the more potent antioxidant compounds and thus guide further purification. The purified antioxidant compounds were elucidated using NMR to determine the structure of the antioxidant compounds.Rhodes UniversityFaculty of Science, Biochemistry, Microbiology and Biotechnology2007ThesisMastersMScxii, 120, xxiii p.: ill. (some col.)pdfvital:3922http://hdl.handle.net/10962/d1003981EnglishRagubeer, Nasheen
collection NDLTD
language English
format Others
sources NDLTD
topic Antioxidants
Nervous system -- Degeneration
Electrochemical analysis
Marine algae
Natural products
Marine metabolites
Sargassum
Legumes
Nuclear magnetic resonance
spellingShingle Antioxidants
Nervous system -- Degeneration
Electrochemical analysis
Marine algae
Natural products
Marine metabolites
Sargassum
Legumes
Nuclear magnetic resonance
Ragubeer, Nasheen
Evaluation and application of electroanalysis for the determination of antioxidants
description The role of antioxidants in the prevention of neurodegenerative diseases has been well documented. The use of synthetic antioxidants has decreased due to the ssociation of these compounds with certain cancers. Thus, the search for novel natural antioxidants has gained much focus in research. Most common methods of determining antioxidant capacity are the radical generated assays and biological assays such as lipid peroxidation and the nitroblue tetrazolium assay. Electrochemical methods have been proposed for the determination of bio-active compounds such as antioxidants. The electrochemical methods of cyclic voltammetry and square wave voltammetry were evaluated for the determination of antioxidant capacity initially examining known antioxidants and then using plant extracts of Sutherlandia frutescens as a case study. The antioxidant properties determined by electrochemical methods were validated utilising the non-biological methods of the DPPH, TEAC, ferrozine and FC assay and biological pharmacological methods. The results indicated that Sutherlandia frutescens contains potent antioxidant compounds that are able to reduce lipid peroxidation. The electrochemical techniques of square wave voltammetry and cyclic voltammetry were applied for the screening of a large number of extracts of various algae for the detection of antioxidant compounds. The results indicated that electrochemistry can be used as a preliminary method for the rapid screening of a large number of crude samples for antioxidant compounds. Electrochemical methods were also evaluated as a method for guiding the isolation and purification of antioxidant metabolites in Sargassum elegans. Solvent partitioning and fractionation of the marine alga allowed for the purification of antioxidant compounds. At each step of purification electrochemical methods were utilized to determine which fractions contained the more potent antioxidant compounds and thus guide further purification. The purified antioxidant compounds were elucidated using NMR to determine the structure of the antioxidant compounds.
author Ragubeer, Nasheen
author_facet Ragubeer, Nasheen
author_sort Ragubeer, Nasheen
title Evaluation and application of electroanalysis for the determination of antioxidants
title_short Evaluation and application of electroanalysis for the determination of antioxidants
title_full Evaluation and application of electroanalysis for the determination of antioxidants
title_fullStr Evaluation and application of electroanalysis for the determination of antioxidants
title_full_unstemmed Evaluation and application of electroanalysis for the determination of antioxidants
title_sort evaluation and application of electroanalysis for the determination of antioxidants
publisher Rhodes University
publishDate 2007
url http://hdl.handle.net/10962/d1003981
work_keys_str_mv AT ragubeernasheen evaluationandapplicationofelectroanalysisforthedeterminationofantioxidants
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