A gas chromatography-isotope ratio mass spectrometry (GC-IRMS) technique for detecting the production of hydroxyl radicals is described. The decarboxylation of [7-13COOH]benzoic acid in the presence of a hydroxyl radicals source (a mixture of porphyrin and hydrogen peroxide) was followed by direct measurement of the 13CO2/12CO2 isotopic ratio. The production of hydroxyl radicals by the mixtures of porphyrin-hydrogen peroxide was proved by comparative study with electron spin resonance spectrometry and high-performance liquid chromatography analysis of hydroxylation products of benzoic acid. The water-soluble radical scavengers methanol, mannitol, and dimethyl sulfoxide led to the inhibition of 13CO2 production from [7-13COOH]benzoic acid. In contrast, high concentrations of the antioxidant ascorbate strongly increased [7-13COOH]benzoic acid decarboxylation. Finally, the use of anaerobic conditions showed that decarboxylation was independent of the presence of oxygen. The absence of the effect of superoxide dismutase could exclude a possible effect of the superoxide ion. This nonradioactive technique offers many advantages compared to the well-established method for detecting hydroxyl radicals based on the decarboxylation of [7-14COOH]benzoic acid. It is rapid and easy to perform as a simple tube test and is highly reliable for detecting hydroxyl radicals. This method provides an on-line analysis of carbon dioxide compared to the radiochemical method. In addition, 13CO2-enrichment measurements led to easy kinetic studies with high sensitivity and semiquantitative determinations.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1006/abio.1994.1308 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Photochemistry of Microsolvated Nitrous Acid: Observation of the Water-Separated Complex of Nitric Oxide and Hydroxyl Radical.
J Phys Chem Lett
January 2025
Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433, China.
The photochemistry of nitrous acid (HONO) plays a crucial role in atmospheric chemistry as it serves as a key source of hydroxyl radicals (OH) in the atmosphere; however, our comprehension of the underlying mechanism for the photochemistry of HONO especially in the presence of water is far from being complete as the transient intermediates in the photoreactions have not been observed. Herein, we report the photochemistry of microsolvated HONO by water in a cryogenic N matrix. Specifically, the 1:1 hydrogen-bonded water complex of HONO was facially prepared in the matrix through stepwise photolytic O oxidation of the water complex of imidogen (NH-HO) via the intermediacy of the elusive water complex of peroxyl isomer HNOO.
View Article and Find Full Text PDFBromide-promoted cascade annulation of isocyanobiaryls with aldehydes through photoredox catalysis.
Org Biomol Chem
January 2025
Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, China.
Herein, we report a cascade annulation of readily available isocyanobiaryls with simple aldehydes photoredox catalysis, providing a straightforward approach towards valuable 6-hydroxyalkylated phenanthridines. Mechanistic studies indicated the generation of a key acyl radical from aldehydes by hydrogen atom abstraction with a bromine radical. This protocol exhibits exceptional chemoselectivity, excellent tolerance of various functional groups and mild reaction conditions.
View Article and Find Full Text PDFAnchoring Ru single-atoms on MXene achieves dual-enzyme activities for mild photothermal augmented nanocatalytic therapy.
Nanoscale
January 2025
Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin, 150001, P. R. China.
Single-atom catalysts with abnormally high catalytic activity have garnered extensive attention and interest for their application in tumor therapy. Despite the advancements made with current nanotherapeutic agents, developing efficient systems for cancer treatment remains challenging due to low activity, uncontrollable behavior, and nonselective interactions. Herein, we have constructed Ru single-atom-anchored MXene nanozymes (Ru-TiCT-PEG) with a mild photothermal effect and multi-enzyme catalytic activity for synergistic tumor therapy.
View Article and Find Full Text PDFMechanisms involved in the valproic acid-induced hepatotoxicity: A Comprehensive review.
Toxicol Mech Methods
January 2025
Department of Pharmacology, SVKM's NMIMS School of Pharmacy and Technology Management, Babulde, Shirpur, 425405 Maharashtra, India.
Adverse drug reactions (ADR) remain a challenge in modern healthcare, particularly given the increasing complexity of therapeutics. WHO's definition of an adverse drug reaction as a response to a drug that is noxious and unintended and occurs at doses normally used in man for the prophylaxis, diagnosis or therapy of disease, or for modification of physiological function. This definition underscores the importance of monitoring and mitigating unintended drug effects, particularly for widely used medications like valproic acid (VPA).
View Article and Find Full Text PDFA Multifunctional MIL-101-NH(Fe) Nanoplatform for Synergistic Melanoma Therapy.
Int J Nanomedicine
January 2025
Department of Pharmacy, The Affiliated Hospital, Southwest Medical University, Luzhou, Sichuan, 646000, People's Republic of China.
Background: Melanoma is an aggressive form of skin cancer, and single-modality treatments often fail to prevent tumor recurrence and metastasis. Combination therapy has emerged as an effective approach to improve treatment outcomes.
Methods: In this study, we developed a multifunctional nanoplatform, MIL@DOX@ICG, utilizing MIL-101-NH(Fe) as a carrier to co-deliver the chemotherapeutic agent doxorubicin (DOX) and the photosensitizer indocyanine green (ICG).
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!