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Larin ACR, Pfrunder MC, Mullen KM, Wiedbrauk S, Boase NR, Fairfull-Smith KE. Synergistic or antagonistic antioxidant combinations - a case study exploring flavonoid-nitroxide hybrids. Org Biomol Chem 2023; 21:1780-1792. [PMID: 36728689 DOI: 10.1039/d2ob02101c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Neurodegenerative diseases impose a considerable medical and public health burden on populations throughout the world. Oxidative stress, an imbalance in pro-oxidant/antioxidant homeostasis that leads to the generation of reactive oxygen species (ROS), has been implicated in the progression of a number of neurodegenerative diseases. The manipulation of ROS levels may represent a promising treatment option to slow down neurodegeneration, although adequate potency of treatments has not yet been achieved. Using a hybrid pharmacology approach, free radical nitroxide antioxidants were hybridised with a class of natural antioxidants, flavonoids, to form a potential multitargeted antioxidant. Modification of the Baker-Venkataraman reaction achieved the flavonoid-nitroxide hybrids (6-9) in modest yields. Antioxidant evaluation of the hybrids by cyclic voltammetry showed both redox functionalities were still active, with little influence on oxidation potential. Assessment of the peroxyl radical scavenging ability through an ORAC assay showed reduced antioxidant activity of the hybrids compared to their individual components. It was hypothesized that the presence of the phenol in the hybrids creates a more acidic medium which does not favour regeneration of the nitroxide from the corresponding oxammonium cation, disturbing the typical catalytic cycle of peroxyl radical scavenging by nitroxides. This work highlights the potential intricacies involved with drug hybridization as a strategy for new therapeutic development.
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Affiliation(s)
- Astrid C R Larin
- School of Chemistry and Physics, Faculty of Science, Queensland University of Technology, Brisbane, Queensland, 4001, Australia.,Centre for Materials Science, Queensland University of Technology, Brisbane, Queensland, 4001, Australia.
| | - Michael C Pfrunder
- School of Chemistry and Physics, Faculty of Science, Queensland University of Technology, Brisbane, Queensland, 4001, Australia.,Centre for Materials Science, Queensland University of Technology, Brisbane, Queensland, 4001, Australia.
| | - Kathleen M Mullen
- School of Chemistry and Physics, Faculty of Science, Queensland University of Technology, Brisbane, Queensland, 4001, Australia.,Centre for Materials Science, Queensland University of Technology, Brisbane, Queensland, 4001, Australia.
| | - Sandra Wiedbrauk
- School of Chemistry and Physics, Faculty of Science, Queensland University of Technology, Brisbane, Queensland, 4001, Australia.,Centre for Materials Science, Queensland University of Technology, Brisbane, Queensland, 4001, Australia.
| | - Nathan R Boase
- School of Chemistry and Physics, Faculty of Science, Queensland University of Technology, Brisbane, Queensland, 4001, Australia.,Centre for Materials Science, Queensland University of Technology, Brisbane, Queensland, 4001, Australia.
| | - Kathryn E Fairfull-Smith
- School of Chemistry and Physics, Faculty of Science, Queensland University of Technology, Brisbane, Queensland, 4001, Australia.,Centre for Materials Science, Queensland University of Technology, Brisbane, Queensland, 4001, Australia.
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Narreddula VR, Boase NR, Ailuri R, Marshall DL, Poad BL, Kelso MJ, Trevitt AJ, Mitchell TW, Blanksby SJ. Introduction of a Fixed-Charge, Photolabile Derivative for Enhanced Structural Elucidation of Fatty Acids. Anal Chem 2019; 91:9901-9909. [DOI: 10.1021/acs.analchem.9b01566] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Venkateswara R. Narreddula
- School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD 4000, Australia
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD 4000, Australia
| | - Nathan R. Boase
- School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD 4000, Australia
| | - Ramesh Ailuri
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
| | - David L. Marshall
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD 4000, Australia
| | - Berwyck L.J. Poad
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD 4000, Australia
| | - Michael J. Kelso
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Adam J. Trevitt
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Todd W. Mitchell
- School of Medicine, University of Wollongong, Wollongong, NSW 2522, Australia
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Stephen J. Blanksby
- School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD 4000, Australia
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD 4000, Australia
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Hancock SE, Ailuri R, Marshall DL, Brown SHJ, Saville JT, Narreddula VR, Boase NR, Poad BLJ, Trevitt AJ, Willcox MDP, Kelso MJ, Mitchell TW, Blanksby SJ. Mass spectrometry-directed structure elucidation and total synthesis of ultra-long chain ( O-acyl)-ω-hydroxy fatty acids. J Lipid Res 2018; 59:1510-1518. [PMID: 29907595 DOI: 10.1194/jlr.m086702] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 06/13/2018] [Indexed: 01/24/2023] Open
Abstract
The (O-acyl)-ω-hydroxy FAs (OAHFAs) comprise an unusual lipid subclass present in the skin, vernix caseosa, and meibomian gland secretions. Although they are structurally related to the general class of FA esters of hydroxy FAs (FAHFAs), the ultra-long chain (30-34 carbons) and the putative ω-substitution of the backbone hydroxy FA suggest that OAHFAs have unique biochemistry. Complete structural elucidation of OAHFAs has been challenging because of their low abundance within complex lipid matrices. Furthermore, because these compounds occur as a mixture of closely related isomers, insufficient spectroscopic data have been obtained to guide structure confirmation by total synthesis. Here, we describe the full molecular structure of ultra-long chain OAHFAs extracted from human meibum by exploiting the gas-phase purification of lipids through multi-stage MS and novel multidimensional ion activation methods. The analysis elucidated sites of unsaturation, the stereochemical configuration of carbon-carbon double bonds, and ester linkage regiochemistry. Such isomer-resolved MS guided the first total synthesis of an ultra-long chain OAHFA, which, in turn, confirmed the structure of the most abundant OAHFA found in human meibum, OAHFA 50:2. The availability of a synthetic OAHFA opens new territory for future investigations into the unique biophysical and biochemical properties of these lipids.
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Affiliation(s)
- Sarah E Hancock
- School of Medicine, University of Wollongong, Wollongong, New South Wales, Australia.,Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, New South Wales, Australia
| | - Ramesh Ailuri
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, New South Wales, Australia.,School of Chemistry, University of Wollongong, Wollongong, New South Wales, Australia
| | - David L Marshall
- Central Analytical Research Facility, Institute for Future Environments Queensland University of Technology, Brisbane, Queensland, Australia
| | - Simon H J Brown
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, New South Wales, Australia.,School of Biological Sciences, University of Wollongong, Wollongong, New South Wales, Australia
| | - Jennifer T Saville
- School of Chemistry, University of Wollongong, Wollongong, New South Wales, Australia
| | - Venkateswara R Narreddula
- Central Analytical Research Facility, Institute for Future Environments Queensland University of Technology, Brisbane, Queensland, Australia
| | - Nathan R Boase
- School of Chemistry, Physics, and Mechanical Engineering, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Berwyck L J Poad
- Central Analytical Research Facility, Institute for Future Environments Queensland University of Technology, Brisbane, Queensland, Australia
| | - Adam J Trevitt
- School of Chemistry, University of Wollongong, Wollongong, New South Wales, Australia
| | - Mark D P Willcox
- School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia
| | - Michael J Kelso
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, New South Wales, Australia.,School of Chemistry, University of Wollongong, Wollongong, New South Wales, Australia
| | - Todd W Mitchell
- School of Medicine, University of Wollongong, Wollongong, New South Wales, Australia .,Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, New South Wales, Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility, Institute for Future Environments Queensland University of Technology, Brisbane, Queensland, Australia .,School of Chemistry, Physics, and Mechanical Engineering, Queensland University of Technology, Brisbane, Queensland, Australia
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