Journal ArticleDOI
Screening of xanthine oxidase inhibitors in complex mixtures using online HPLC coupled with postcolumn fluorescence-based biochemical detection.
TLDR
The inhibition of XO is recognized as one of the therapeutic approaches to treat gout and the developed online system was applicable to complex mixtures.Abstract:
Xanthine oxidase (XO) catalyzes the metabolism of hypoxanthine and xanthine to uric acid, the overproduction and/or underexcretion of which could cause the incidence of hyperuricemia such as gout. Herein, the inhibition of XO is recognized as one of the therapeutic approaches to treat gout. In the present study, an off-line fluorescence-based microplate method was first developed for an XO assay in which the enzyme converted pterin to its fluorescent metabolite isoxanthopterin. Then, a postcolumn continuous XO assay as a means of bioactivity assessment was coupled to HPLC separation to establish the online HPLC with diode array detection, biochemical detection, and MS/MS system for the screening of XO inhibitors. The availability of the online system was first tested with a positive drug, allopurinol, a well-known XO inhibitor, and subsequent analysis of Scutellaria baicalensis extract showed that two main bioactive compounds with XO inhibitory activities were observed, indicating that the developed online system was applicable to complex mixtures.read more
Citations
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Toward an Understanding of Structural Insights of Xanthine and Aldehyde Oxidases: An Overview of their Inhibitors and Role in Various Diseases
TL;DR: A comprehensive review on the xanthine and aldehyde oxidases pertaining to their structures, functions, pathophysiological role, and a comparative analysis ofStructural prerequisites for inhibitor specificity to both the enzymes keeping in view of the existing X‐ray structures is put forth.
Journal ArticleDOI
Advanced strategies for quality control of Chinese medicines.
TL;DR: Novel strategies related to quality marker discovery, reference compound development and advanced approaches (focused on glyco‐analysis) for quality control, during 2011–2016, were summarized and discussed.
Journal ArticleDOI
Discovery of active components in herbs using chromatographic separation coupled with online bioassay.
TL;DR: This review mainly focused on the online strategies, which integrated the separation science, mass spectrometry, and bioactivity screening in a single platform, allowing simultaneous screening and characterization of active compounds from complex matrices, especially from the herbs.
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Rapid screening and detection of XOD inhibitors from S. tamariscina by ultrafiltration LC-PDA–ESI-MS combined with HPCCC
TL;DR: The results reveal that the method for systematic screening, identification, and isolation of bioactive components in S. tamariscina is feasible and efficient, and could be expected to extend to screening and separation of other enzyme inhibitors.
Journal ArticleDOI
Detection of Enzyme Inhibitors in Crude Natural Extracts Using Droplet-Based Microfluidics Coupled to HPLC
TL;DR: The feasibility of carrying out enzyme inhibiting assays inside nanoliter droplets with the different components of a natural crude extract after being separated by a coupled HPLC column is demonstrated and represents an advance in the miniaturization of natural products screening.
References
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Journal ArticleDOI
The purine path to chemotherapy
TL;DR: Research on antimetabolites of nucleic acid purines led to drugs for the treatment of acute leukemia, gout and hyperuricemia, and herpesvirus infections, and for the prevention of organ transplant rejection.
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Inhibition of Xanthine Oxidase by Flavonoids
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Progress towards the discovery of xanthine oxidase inhibitors.
TL;DR: The State of the Art will be presented, which includes a summary of the progress made over the past years in the knowledge of the structure and mechanism of the enzyme, associated pathological states, and in the efforts made towards the development of new xanthine oxidase inhibitors.
Journal Article
Inhibitory effects of flavonoids on xanthine oxidase.
TL;DR: Nine naturally occurring flavonoids have been tested the inhibitory effects on xanthine oxidase, and baicalein displayed the strongest activity, followed by wogonin and then baicalin, which induced uncompetitive inhibition of the enzyme with respect to xanhtine.
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A sensitive fluorometric assay for measuring xanthine dehydrogenase and oxidase in tissues.
TL;DR: The relative proportions and specific activities of xanthine oxidase and dehydrogenase determined by the fluorometric pterin assay are comparable with the spectrophotometric measurement of activities present in rat liver, intestine, kidney, and plasma.