Critical Effect of Oxygen Concentration and Acidity on the Efficiency of Photodegradation of Levofloxacin with Solar UVB Light; Cytotoxicity on Mammalian Cells of the Photoproducts and Its Activity on Pathogenic Bacteria

Levofloxacin is an antibiotic classified as an emerging contaminant. Its presence in aquatic environments represents potential risks to ecosystems and human health, making its removal during wastewater treatment of relevant importance. Here, we present a comprehensive kinetic analysis of levofloxaci...

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Main Authors: Macarena Agostina Biondi, Mariana Belén Spesia, María Carola Sabini, María Alicia Biasutti, Hernán Alfredo Montejano, Eugenia Reynoso
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Compounds
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Online Access:https://www.mdpi.com/2673-6918/5/2/23
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author Macarena Agostina Biondi
Mariana Belén Spesia
María Carola Sabini
María Alicia Biasutti
Hernán Alfredo Montejano
Eugenia Reynoso
author_facet Macarena Agostina Biondi
Mariana Belén Spesia
María Carola Sabini
María Alicia Biasutti
Hernán Alfredo Montejano
Eugenia Reynoso
author_sort Macarena Agostina Biondi
collection DOAJ
description Levofloxacin is an antibiotic classified as an emerging contaminant. Its presence in aquatic environments represents potential risks to ecosystems and human health, making its removal during wastewater treatment of relevant importance. Here, we present a comprehensive kinetic analysis of levofloxacin photodegradation under UVB solar irradiation, with emphasis on the influence of pH and dissolved oxygen, two conditions that can vary widely in wastewater and impact treatment efficiency. We also investigated the formation and role of reactive oxygen species in the degradation mechanism, as well as the cytotoxicity and antibacterial activity of photoproducts. Our findings reveal that the efficiency of levofloxacin photodegradation is highly dependent on environmental conditions; it requires neutral or slightly alkaline pH and a high concentration of dissolved oxygen, a situation not always observed in contaminated waters. Several reactive oxygen species are generated, with singlet oxygen being the most reactive with the antibiotic. We report for the first time the singlet oxygen quantum yield from levofloxacin. Bioassays demonstrated that photoproducts neither exhibit antibacterial activity nor induce significant cytotoxicity. Our study suggests that UVB treatment of contaminated effluent containing levofloxacin could be an effective and environmentally safe strategy for the antibiotic degradation under certain conditions of pH and dissolved oxygen.
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spelling doaj-art-438757db10204baaaba1a0174bc6f2562025-08-20T02:24:29ZengMDPI AGCompounds2673-69182025-06-01522310.3390/compounds5020023Critical Effect of Oxygen Concentration and Acidity on the Efficiency of Photodegradation of Levofloxacin with Solar UVB Light; Cytotoxicity on Mammalian Cells of the Photoproducts and Its Activity on Pathogenic BacteriaMacarena Agostina Biondi0Mariana Belén Spesia1María Carola Sabini2María Alicia Biasutti3Hernán Alfredo Montejano4Eugenia Reynoso5Departamento de Química, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto (UNRC), Ruta Nacional 36 Km 601, Río Cuarto X5804BYA, ArgentinaDepartamento de Química, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto (UNRC), Ruta Nacional 36 Km 601, Río Cuarto X5804BYA, ArgentinaInstituto de Investigaciones en Ciencias de la Salud (INICSA), CONICET–UNC, Ciudad Universitaria, Córdoba X5000, ArgentinaDepartamento de Química, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto (UNRC), Ruta Nacional 36 Km 601, Río Cuarto X5804BYA, ArgentinaDepartamento de Química, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto (UNRC), Ruta Nacional 36 Km 601, Río Cuarto X5804BYA, ArgentinaDepartamento de Química, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto (UNRC), Ruta Nacional 36 Km 601, Río Cuarto X5804BYA, ArgentinaLevofloxacin is an antibiotic classified as an emerging contaminant. Its presence in aquatic environments represents potential risks to ecosystems and human health, making its removal during wastewater treatment of relevant importance. Here, we present a comprehensive kinetic analysis of levofloxacin photodegradation under UVB solar irradiation, with emphasis on the influence of pH and dissolved oxygen, two conditions that can vary widely in wastewater and impact treatment efficiency. We also investigated the formation and role of reactive oxygen species in the degradation mechanism, as well as the cytotoxicity and antibacterial activity of photoproducts. Our findings reveal that the efficiency of levofloxacin photodegradation is highly dependent on environmental conditions; it requires neutral or slightly alkaline pH and a high concentration of dissolved oxygen, a situation not always observed in contaminated waters. Several reactive oxygen species are generated, with singlet oxygen being the most reactive with the antibiotic. We report for the first time the singlet oxygen quantum yield from levofloxacin. Bioassays demonstrated that photoproducts neither exhibit antibacterial activity nor induce significant cytotoxicity. Our study suggests that UVB treatment of contaminated effluent containing levofloxacin could be an effective and environmentally safe strategy for the antibiotic degradation under certain conditions of pH and dissolved oxygen.https://www.mdpi.com/2673-6918/5/2/23photodegradationsolar UVB lightlevofloxacinpHdissolved oxygenantimicrobial activity
spellingShingle Macarena Agostina Biondi
Mariana Belén Spesia
María Carola Sabini
María Alicia Biasutti
Hernán Alfredo Montejano
Eugenia Reynoso
Critical Effect of Oxygen Concentration and Acidity on the Efficiency of Photodegradation of Levofloxacin with Solar UVB Light; Cytotoxicity on Mammalian Cells of the Photoproducts and Its Activity on Pathogenic Bacteria
Compounds
photodegradation
solar UVB light
levofloxacin
pH
dissolved oxygen
antimicrobial activity
title Critical Effect of Oxygen Concentration and Acidity on the Efficiency of Photodegradation of Levofloxacin with Solar UVB Light; Cytotoxicity on Mammalian Cells of the Photoproducts and Its Activity on Pathogenic Bacteria
title_full Critical Effect of Oxygen Concentration and Acidity on the Efficiency of Photodegradation of Levofloxacin with Solar UVB Light; Cytotoxicity on Mammalian Cells of the Photoproducts and Its Activity on Pathogenic Bacteria
title_fullStr Critical Effect of Oxygen Concentration and Acidity on the Efficiency of Photodegradation of Levofloxacin with Solar UVB Light; Cytotoxicity on Mammalian Cells of the Photoproducts and Its Activity on Pathogenic Bacteria
title_full_unstemmed Critical Effect of Oxygen Concentration and Acidity on the Efficiency of Photodegradation of Levofloxacin with Solar UVB Light; Cytotoxicity on Mammalian Cells of the Photoproducts and Its Activity on Pathogenic Bacteria
title_short Critical Effect of Oxygen Concentration and Acidity on the Efficiency of Photodegradation of Levofloxacin with Solar UVB Light; Cytotoxicity on Mammalian Cells of the Photoproducts and Its Activity on Pathogenic Bacteria
title_sort critical effect of oxygen concentration and acidity on the efficiency of photodegradation of levofloxacin with solar uvb light cytotoxicity on mammalian cells of the photoproducts and its activity on pathogenic bacteria
topic photodegradation
solar UVB light
levofloxacin
pH
dissolved oxygen
antimicrobial activity
url https://www.mdpi.com/2673-6918/5/2/23
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