Synthesis and Characterisation of Azo Chromophores Tailored for their In vitro Antibacterial and Antioxidant Activities

Non-communicable disease and bacterial resistance are complex combinations of problems that require immediate and effective alternatives. Concerning that, in this study, two series of azophenol derivatives 54a-m and 60a-m were successfully synthesised via diazo coupling reaction by employing 4-amino...

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Main Author:	Kai Wei, Yeo
Format:	Thesis
Language:	English English English English
Published:	2024
Subjects:	Q Science (General) QD Chemistry
Online Access:	http://ir.unimas.my/id/eprint/46402/3/Restricted%20of%20Thesis%20for%20Graduation_Yeo%20Kai%20Wei.pdf http://ir.unimas.my/id/eprint/46402/4/Thesis%20Ms._%20Yeo%20Kai%20Wei%20-%206%20pages%20retricted..pdf http://ir.unimas.my/id/eprint/46402/5/DowF_Yeo%20Kai%20Wei.pdf http://ir.unimas.my/id/eprint/46402/6/Thesis%20Ms._%20Yeo%20Kai%20Wei.restricted.pdf
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spelling	my-unimas-ir.464022024-10-21T00:09:13Z Synthesis and Characterisation of Azo Chromophores Tailored for their In vitro Antibacterial and Antioxidant Activities 2024-10-04 Kai Wei, Yeo Q Science (General) QD Chemistry Non-communicable disease and bacterial resistance are complex combinations of problems that require immediate and effective alternatives. Concerning that, in this study, two series of azophenol derivatives 54a-m and 60a-m were successfully synthesised via diazo coupling reaction by employing 4-aminoacetanilide and p-toluidine, respectively as starting materials. Structural confirmation was done using CHNS elemental analysis, FTIR, 1H and 13C NMR spectroscopies. Both series were tested for antibacterial activities against Staphylococcus aureus and Escherichia coli as well as antioxidant activities employing DPPH and FRAP assays. The antibacterial study on 60a-m by Kirby-Bauer disc diffusion method showed poor inhibition towards both tested strains possibly due to the presence of amide moiety masked the cytoplasmic membrane depolarisation. In contrast, compounds 60a-m showed promising antibacterial activity portraying a better inhibition against S. aureus than E. coli potentially due to the difference in the cell wall structure with the latter being more complex. Further minimum inhibitory concentration (MIC) evaluation by turbidimetric kinetic method on 60a-m indicated that compound 60i (m-Br) resulted in a comparable MIC of 112.40 ppm (E. coli) and 103.95 ppm (S. aureus) with ampicillin 112.92 ppm (E. coli) and 95.70 ppm (S. aureus). This promising antibacterial activity of 60i (m-Br) was suggested due to its molecular size and polarisation ability leads to the formation of van der Waals interactions with the DNA of microbes. On the other hand, antioxidants evaluation on 54a-m and 60a-m by DPPH assay gave an IC25 in the range of 5.4 to 199.5 ppm as compared to ascorbic acid as standard at IC25 of 9.5ppm, while in FRAP assay gave a value of 12.29 to 210.95 mg Trolox Eq mg/ml with ascorbic acid gave 70.43 mg Trolox Eq mg/ml. Notably, the presence of the methoxy group in 60a-m enhances the antioxidant activities by increasing the electron cloud density of the benzene ring, especially when positioned at ortho- and para- of the hydroxyl group. Universiti Malaysia Sarawak 2024-10 Thesis http://ir.unimas.my/id/eprint/46402/ http://ir.unimas.my/id/eprint/46402/3/Restricted%20of%20Thesis%20for%20Graduation_Yeo%20Kai%20Wei.pdf text en public http://ir.unimas.my/id/eprint/46402/4/Thesis%20Ms._%20Yeo%20Kai%20Wei%20-%206%20pages%20retricted..pdf text en public http://ir.unimas.my/id/eprint/46402/5/DowF_Yeo%20Kai%20Wei.pdf text en public http://ir.unimas.my/id/eprint/46402/6/Thesis%20Ms._%20Yeo%20Kai%20Wei.restricted.pdf text en public masters Universiti Malaysia Sarawak Faculty of Resource Science and Technology
institution	Universiti Malaysia Sarawak
collection	UNIMAS Institutional Repository
language	English English English English
topic	Q Science (General) QD Chemistry
spellingShingle	Q Science (General) QD Chemistry Kai Wei, Yeo Synthesis and Characterisation of Azo Chromophores Tailored for their In vitro Antibacterial and Antioxidant Activities
description	Non-communicable disease and bacterial resistance are complex combinations of problems that require immediate and effective alternatives. Concerning that, in this study, two series of azophenol derivatives 54a-m and 60a-m were successfully synthesised via diazo coupling reaction by employing 4-aminoacetanilide and p-toluidine, respectively as starting materials. Structural confirmation was done using CHNS elemental analysis, FTIR, 1H and 13C NMR spectroscopies. Both series were tested for antibacterial activities against Staphylococcus aureus and Escherichia coli as well as antioxidant activities employing DPPH and FRAP assays. The antibacterial study on 60a-m by Kirby-Bauer disc diffusion method showed poor inhibition towards both tested strains possibly due to the presence of amide moiety masked the cytoplasmic membrane depolarisation. In contrast, compounds 60a-m showed promising antibacterial activity portraying a better inhibition against S. aureus than E. coli potentially due to the difference in the cell wall structure with the latter being more complex. Further minimum inhibitory concentration (MIC) evaluation by turbidimetric kinetic method on 60a-m indicated that compound 60i (m-Br) resulted in a comparable MIC of 112.40 ppm (E. coli) and 103.95 ppm (S. aureus) with ampicillin 112.92 ppm (E. coli) and 95.70 ppm (S. aureus). This promising antibacterial activity of 60i (m-Br) was suggested due to its molecular size and polarisation ability leads to the formation of van der Waals interactions with the DNA of microbes. On the other hand, antioxidants evaluation on 54a-m and 60a-m by DPPH assay gave an IC25 in the range of 5.4 to 199.5 ppm as compared to ascorbic acid as standard at IC25 of 9.5ppm, while in FRAP assay gave a value of 12.29 to 210.95 mg Trolox Eq mg/ml with ascorbic acid gave 70.43 mg Trolox Eq mg/ml. Notably, the presence of the methoxy group in 60a-m enhances the antioxidant activities by increasing the electron cloud density of the benzene ring, especially when positioned at ortho- and para- of the hydroxyl group.
format	Thesis
qualification_level	Master's degree
author	Kai Wei, Yeo
author_facet	Kai Wei, Yeo
author_sort	Kai Wei, Yeo
title	Synthesis and Characterisation of Azo Chromophores Tailored for their In vitro Antibacterial and Antioxidant Activities
title_short	Synthesis and Characterisation of Azo Chromophores Tailored for their In vitro Antibacterial and Antioxidant Activities
title_full	Synthesis and Characterisation of Azo Chromophores Tailored for their In vitro Antibacterial and Antioxidant Activities
title_fullStr	Synthesis and Characterisation of Azo Chromophores Tailored for their In vitro Antibacterial and Antioxidant Activities
title_full_unstemmed	Synthesis and Characterisation of Azo Chromophores Tailored for their In vitro Antibacterial and Antioxidant Activities
title_sort	synthesis and characterisation of azo chromophores tailored for their in vitro antibacterial and antioxidant activities
granting_institution	Universiti Malaysia Sarawak
granting_department	Faculty of Resource Science and Technology
publishDate	2024
url	http://ir.unimas.my/id/eprint/46402/3/Restricted%20of%20Thesis%20for%20Graduation_Yeo%20Kai%20Wei.pdf http://ir.unimas.my/id/eprint/46402/4/Thesis%20Ms._%20Yeo%20Kai%20Wei%20-%206%20pages%20retricted..pdf http://ir.unimas.my/id/eprint/46402/5/DowF_Yeo%20Kai%20Wei.pdf http://ir.unimas.my/id/eprint/46402/6/Thesis%20Ms._%20Yeo%20Kai%20Wei.restricted.pdf
_version_	1818611695198666752

Synthesis and Characterisation of Azo Chromophores Tailored for their In vitro Antibacterial and Antioxidant Activities

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