Identification and Mechanistic Analysis of Toxic Degradation Products in the Advanced Oxidation Pathways of Fluoroquinolone Antibiotics
The degradation of fluoroquinolones (FQs) via advanced oxidation processes (AOPs) is a promising avenue, yet the complete mineralization of certain FQ molecules remains elusive, raising concerns about the formation of toxic by-products. This study delineates five primary AOP degradation pathways for...
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MDPI AG
2024-03-01
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| Series: | Toxics |
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| Online Access: | https://www.mdpi.com/2305-6304/12/3/203 |
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| author | Shuhai Sun Zhonghe Wang Qikun Pu Xinao Li Yuhan Cui Hao Yang Yu Li |
| author_facet | Shuhai Sun Zhonghe Wang Qikun Pu Xinao Li Yuhan Cui Hao Yang Yu Li |
| author_sort | Shuhai Sun |
| collection | DOAJ |
| description | The degradation of fluoroquinolones (FQs) via advanced oxidation processes (AOPs) is a promising avenue, yet the complete mineralization of certain FQ molecules remains elusive, raising concerns about the formation of toxic by-products. This study delineates five primary AOP degradation pathways for 16 commercially available FQ molecules, inferred from existing literature. Density functional theory (DFT) was employed to calculate the bond dissociation energies within these pathways to elucidate the correlation between bond strength and molecular architecture. Subsequently, Comparative Molecular Similarity Index Analysis (CoMSIA) models were constructed for various degradation reactions, including piperazine ring cleavage, defluorination, hydroxylation, and piperazine ring hydroxylation. Three-dimensional contour maps generated from these models provide a deeper understanding of the interplay between FQ molecular structure and bond dissociation energy. Furthermore, toxicity predictions for 16 FQ molecules and their advanced oxidation intermediates, conducted using VEGA 1.2.3 software, indicate that degradation products from pathways P2 and P5 pose a heightened health risk relative to their parent compounds. Furthermore, the application of the Multwfn program to compute the Fukui function for FQ molecules discerns the disparity in degradation propensities, highlighting that N atoms with higher f0 values can augment the likelihood of piperazine ring cleavage. HOMO-LUMO distribution diagrams further confirm that methoxy substitution at the 1-position leads to a dilution of HOMOs on the piperazine ring and an increased energy gap for free radical reactions, diminishing the reactivity with hydroxyl radicals. This study elucidates the pivotal role of structural characteristics in FQ antibiotics for their degradation efficiency within AOPs and unveils the underlying mechanisms of bond dissociation energy disparities. The toxicity parameter predictions for FQ molecules and their intermediates offer unique perspectives and theoretical underpinnings for mitigating the use of high-risk FQs and for devising targeted degradation strategies to circumvent the generation of toxic intermediates in AOPs through molecular structure optimization. |
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| language | English |
| last_indexed | 2024-04-24T17:46:56Z |
| publishDate | 2024-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Toxics |
| spelling | doaj.art-20d2aa761bb14b99aae773fc7e2a7fef2024-03-27T14:06:13ZengMDPI AGToxics2305-63042024-03-0112320310.3390/toxics12030203Identification and Mechanistic Analysis of Toxic Degradation Products in the Advanced Oxidation Pathways of Fluoroquinolone AntibioticsShuhai Sun0Zhonghe Wang1Qikun Pu2Xinao Li3Yuhan Cui4Hao Yang5Yu Li6School of Hydraulic and Environmental Engineering, Changchun Institute of Technology, Changchun 130012, ChinaMOE Key Laboratory of Resources and Environmental System Optimization, North China Electric Power University, Beijing 102206, ChinaMOE Key Laboratory of Resources and Environmental System Optimization, North China Electric Power University, Beijing 102206, ChinaMOE Key Laboratory of Resources and Environmental System Optimization, North China Electric Power University, Beijing 102206, ChinaMOE Key Laboratory of Resources and Environmental System Optimization, North China Electric Power University, Beijing 102206, ChinaMOE Key Laboratory of Resources and Environmental System Optimization, North China Electric Power University, Beijing 102206, ChinaMOE Key Laboratory of Resources and Environmental System Optimization, North China Electric Power University, Beijing 102206, ChinaThe degradation of fluoroquinolones (FQs) via advanced oxidation processes (AOPs) is a promising avenue, yet the complete mineralization of certain FQ molecules remains elusive, raising concerns about the formation of toxic by-products. This study delineates five primary AOP degradation pathways for 16 commercially available FQ molecules, inferred from existing literature. Density functional theory (DFT) was employed to calculate the bond dissociation energies within these pathways to elucidate the correlation between bond strength and molecular architecture. Subsequently, Comparative Molecular Similarity Index Analysis (CoMSIA) models were constructed for various degradation reactions, including piperazine ring cleavage, defluorination, hydroxylation, and piperazine ring hydroxylation. Three-dimensional contour maps generated from these models provide a deeper understanding of the interplay between FQ molecular structure and bond dissociation energy. Furthermore, toxicity predictions for 16 FQ molecules and their advanced oxidation intermediates, conducted using VEGA 1.2.3 software, indicate that degradation products from pathways P2 and P5 pose a heightened health risk relative to their parent compounds. Furthermore, the application of the Multwfn program to compute the Fukui function for FQ molecules discerns the disparity in degradation propensities, highlighting that N atoms with higher f0 values can augment the likelihood of piperazine ring cleavage. HOMO-LUMO distribution diagrams further confirm that methoxy substitution at the 1-position leads to a dilution of HOMOs on the piperazine ring and an increased energy gap for free radical reactions, diminishing the reactivity with hydroxyl radicals. This study elucidates the pivotal role of structural characteristics in FQ antibiotics for their degradation efficiency within AOPs and unveils the underlying mechanisms of bond dissociation energy disparities. The toxicity parameter predictions for FQ molecules and their intermediates offer unique perspectives and theoretical underpinnings for mitigating the use of high-risk FQs and for devising targeted degradation strategies to circumvent the generation of toxic intermediates in AOPs through molecular structure optimization.https://www.mdpi.com/2305-6304/12/3/203fluoroquinolonesadvanced oxidation processesdegradation productsenvironmental and human health risk |
| spellingShingle | Shuhai Sun Zhonghe Wang Qikun Pu Xinao Li Yuhan Cui Hao Yang Yu Li Identification and Mechanistic Analysis of Toxic Degradation Products in the Advanced Oxidation Pathways of Fluoroquinolone Antibiotics Toxics fluoroquinolones advanced oxidation processes degradation products environmental and human health risk |
| title | Identification and Mechanistic Analysis of Toxic Degradation Products in the Advanced Oxidation Pathways of Fluoroquinolone Antibiotics |
| title_full | Identification and Mechanistic Analysis of Toxic Degradation Products in the Advanced Oxidation Pathways of Fluoroquinolone Antibiotics |
| title_fullStr | Identification and Mechanistic Analysis of Toxic Degradation Products in the Advanced Oxidation Pathways of Fluoroquinolone Antibiotics |
| title_full_unstemmed | Identification and Mechanistic Analysis of Toxic Degradation Products in the Advanced Oxidation Pathways of Fluoroquinolone Antibiotics |
| title_short | Identification and Mechanistic Analysis of Toxic Degradation Products in the Advanced Oxidation Pathways of Fluoroquinolone Antibiotics |
| title_sort | identification and mechanistic analysis of toxic degradation products in the advanced oxidation pathways of fluoroquinolone antibiotics |
| topic | fluoroquinolones advanced oxidation processes degradation products environmental and human health risk |
| url | https://www.mdpi.com/2305-6304/12/3/203 |
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