An amperometric biosensor based on zucchini (Cucurbita pepo) tissue homogenate is presented. The zucchini tissue homogenate was crosslinked with gelatine using glutaraldehyde and fixed on a pretreated teflon membrane. The zucchini tissue contained the enzyme ascorbate oxidase and this enzyme catalyzed the oxidation of ascorbic acid in the presence of dissolved oxygen. The principle of the measurements was based on the determination of the decrease in the dissolved oxygen level. Determinations were carried out by standard curves, which were obtained by the measurement of the decrease in the oxygen level related to ascorbic acid concentration. Optimization and characterization studies of the biosensor were carried out in detail. First of all, the amounts of zucchini tissue homogenate, gelatin, and glutaraldehyde percentage were optimized. Experimental parameters such as buffer system, pH, buffer concentration, and temperature were also optimized carefully. Thermal stability, storage stability, and repeatability of the biosensor were investigated. A linear response was observed from 5x10(-6) M to 1.2x10(-3) M ascorbic acid. Finally, the results of some plant and drug samples analyzed with the presented biosensor compared with the spectrophotometric method (Tillman reagent) used as a reference.
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http://dx.doi.org/10.3109/10731191003785588 | DOI Listing |
J Med Chem
January 2025
Ma̅tai Ha̅ora - Centre for Redox Biology and Medicine, Department of Biomedical Science and Pathology, University of Otago, Christchurch, Christchurch 8140, New Zealand.
In humans, the 2-oxoglutarate-dependent dioxygenases (2-OGDDs) catalyze hydroxylation reactions involved in cell metabolism, the biosynthesis of small molecules, DNA and RNA demethylation, the hypoxic response and the formation of collagen. The reaction is catalyzed by a highly oxidizing ferryl-oxo species produced when the active site non-heme iron engages molecular oxygen. Enzyme activity is specifically stimulated by l-ascorbic acid (ascorbate, vitamin C), an effect not well mimicked by other reducing agents.
View Article and Find Full Text PDFJ Pharm Biomed Anal
January 2025
Institute of Chemistry, University of Silesia in Katowice, 9 Szkolna Street, Katowice 40-006, Poland; SPIN-Lab Centre for Microscopic Studies on Matter, University of Silesia in Katowice, 75 Pulku Piechoty Street 1, Chorzow 41-500, Poland. Electronic address:
Near-infrared hyperspectral imaging (NIR-HSI) integrated with expert systems can support the monitoring of active pharmaceutical ingredients (APIs) and provide effective quality control of tablet formulations. However, existing quality control methods usually test a limited number of variability sources affecting the final product. This study examines the potential of NIR-HSI (in the spectral range of 935.
View Article and Find Full Text PDFBMC Genom Data
January 2025
School of Epidemiology and Public Health, University of Ottawa, 600 Peter Morand Crescent, Office 101E, Ottawa, Ontario, K1G 5Z3, Canada.
High intraocular pressure (IOP) is an important risk factor for glaucoma, which is influenced by genetic and environmental factors. However, the etiology of high IOP remains uncertain. Metabolites are compounds involved in metabolism which provide a link between the internal (genetic) and external environments.
View Article and Find Full Text PDFSci Rep
January 2025
Ministry of Health, Ankara Ottoman Oral and Dental Health Center, Ankara, Turkey.
Chlorhexidine (CHX) is the most commonly used mouthwash with proven antiplaque and antibacterial activity. The aim is to evaluate the effect of vitamin C (VitC) in CHX mouthwash on plaque accumulation and gingivitis, and to compare it with CHX alone mouthwash and antiseptic phenol-containing mouthwashes. This study conducted as a multicenter, randomized, controlled, double-blind, parallel design clinical study.
View Article and Find Full Text PDFAnal Chim Acta
March 2025
The Radiology Department of Shanxi Provincial People's Hospital Affiliated to Shanxi Medical University, Taiyuan, 030001, China. Electronic address:
Background: Real-time and rapid detection of ingredients in food has important significance for food safety. However, traditional detection methods not only require bulky and costly instruments but also are often based on single-mode analysis, limiting their accuracy and applications in point-of-care testing. Herein, an integrated and miniaturized dual-mode device based on colorimetric and photoacoustic (PA) principles is developed, using Au@Ag nanoparticles (Au@AgNPs) as signal probe and ascorbic acid (AA) and ascorbate oxidase (AAO) as analytes.
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