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Aggregation and inactivation of pancreatic cystatin by riboflavin‐derived singlet oxygen and flavin triplet state: Polyphenols as preventive agents
Author(s) -
Priyadarshini Medha,
Khan Mohd. Shahnawaz,
Bano Bilqees
Publication year - 2012
Publication title -
journal of biochemical and molecular toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.526
H-Index - 58
eISSN - 1099-0461
pISSN - 1095-6670
DOI - 10.1002/jbt.20423
Subject(s) - chemistry , oxidative stress , biochemistry , curcumin , reactive oxygen species , singlet oxygen , quercetin , riboflavin , polyphenol , antioxidant , oxygen , organic chemistry
Caprine pancreatic thiol proteinase inhibitor (PTPI) a cystatin superfamily variant has high affinity for cysteine proteinases providing tight regulation of their proteolytic potential. Oxidative stress buildup in various pancreatic pathologies worsens the disease course often by disturbing the delicate balance between proteinases and their inhibitors. We aimed to study the effect of reactive oxygen species (ROS) on PTPI and to determine the potency of caffeic acid, curcumin and quercetin as agents against the inflicted damage. Fluorescence spectroscopy, polyacrylamide gel electrophoresis, and papain inhibitory assay revealed that photoilluminated riboflavin severely challenged the functional and structural integrity of the inhibitor. Three hundred and fifty micromolar affeic acid or quercetin prevented the damage. Curcumin, however, failed to reverse the changes completely. Conclusively, PTPI rendered dysfunctional by ROS may explain the increased necrotic damage to the host tissue. Also, dietary antioxidants can reverse the riboflavin‐induced protein damage providing an economic and safe anti‐ROS therapy. © 2012 Wiley Periodicals, Inc. J Biochem Mol Toxicol 26:187–192, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/jbt.20423