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BioMed Research International
Volume 2014, Article ID 614506, 10 pages
Research Article

Mechanisms of Ascorbyl Radical Formation in Human Platelet-Rich Plasma

1Division of Cardiology, Shin Kong Wu Ho-Su Memorial Hospital, 95 Wenchang Road, Shihlin Taipei 111, Taiwan
2Graduate Institute of Clinical Medicine, Taipei Medical University, 250 Wu-Hsing Street, Taipei 110, Taiwan
3Department of Cardiology, Cathay General Hospital, 280 Jen Ai Road, Section 4, Taipei 106, Taiwan
4Graduate Institute of Medical Sciences, Taipei Medical University, 250 Wu-Hsing Street, Taipei 110, Taiwan
5Department of Pharmacology, Taipei Medical University, 250 Wu-Hsing Street, Taipei 110, Taiwan

Received 21 November 2013; Accepted 9 January 2014; Published 17 February 2014

Academic Editor: Philip Aloysius Thomas

Copyright © 2014 Kou-Gi Shyu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Recently, many clinical reports have suggested that the ascorbyl free radical () can be treated as a noninvasive, reliable, real-time marker of oxidative stress, but its generation mechanisms in human blood have rarely been discussed. In this study, we used upstream substances, enzyme inhibitors, and free radical scavengers to delineate the mechanisms of formation in human platelet-rich plasma (PRP). Our results show that the doublet signal was detected in PRP samples by using electron spin resonance, and the hyperfine splitting of the doublet signal was gauss and -factor = 2.00627, which was determined to be the . We observed that the inhibitors of NADPH oxidase (NOX), cyclooxygenase (COX), lipoxygenase (LOX), cytochrome P450 (CYP450), mitochondria complex III, and nitric oxide synthase (NOS), but not xanthine oxidase, diminished the intensity of the signal dose dependently. All enzyme inhibitors showed no obvious antioxidant activity during a Fenton reaction assay. In summary, the obtained data suggest that formation is associated with NOX, COX, LOX, CYP450, eNOS, and mitochondria in human PRP.