Mild Mitochondrial Depolarization is Involved in a Neuroprotective Mechanism of Citrus sunki Peel Extract |
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Authors: | Jin‐Ji Wu Yanji Cui Yoon‐Sil Yang Sung‐Cherl Jung Jin Won Hyun Young‐Hee Maeng Deok‐Bae Park Sun‐Ryung Lee Se‐Jae Kim Su‐Yong Eun |
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Institution: | 1. Department of Physiology, Jeju National University School of Medicine, , Jeju‐si, Jeju‐do, 690‐756 Republic of Korea;2. Institute of Medical Science, Jeju National University School of Medicine, , Jeju‐si, Jeju‐do, 690‐756 Republic of Korea;3. Department of Biochemistry, Jeju National University School of Medicine, , Jeju‐si, Jeju‐do, 690‐756 Republic of Korea;4. Department of Pathology, Jeju National University School of Medicine, , Jeju‐si, Jeju‐do, 690‐756 Republic of Korea;5. Department of Histology, Jeju National University School of Medicine, , Jeju‐si, Jeju‐do, 690‐756 Republic of Korea;6. Department of Biology, Jeju National University, , Jeju‐si, Jeju‐do, 690‐756 Republic of Korea |
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Abstract: | Mitochondrial membrane potential (?Ψm) contributes to determining a driving force for calcium to enter the mitochondria. It has been demonstrated that even a small mitochondrial depolarization is sufficient to prevent mitochondrial calcium overload and the subsequent apoptosis. Therefore, mild mitochondrial depolarization has been recently evaluated as a novel mechanism of neuroprotection via inhibiting neurotoxic mitochondrial calcium overload during neuronal insults. In the present study, using both real‐time recording and flow cytometric analyses of ?Ψm, we demonstrated that ethanolic peel extract of Citrus sunki Hort. ex Tanaka (CPE) and its active compounds are capable of inducing a mild mitochondrial depolarization. Polymethoxylated flavones such as nobiletin and tangeretin were found as the active compounds responsible for CPE effects on ?Ψm. Neuronal viability was significantly increased in a dose‐dependent manner by CPE treatment in H2O2‐stimulated HT‐22 cells as an in vitro neuronal insult model. CPE treatment significantly inhibited H2O2‐induced apoptotic processes such as chromatin condensation, caspase 3 activation and anti‐poly (ADP‐ribose) polymerase (PARP) cleavage. CPE treatment significantly blocked mitochondrial calcium overload in H2O2‐stimulated HT‐22 neurons as indicated by rhod‐2 acetoxymethyl ester. Taken together, our findings suggest that CPE and its active compounds may be considered as promising neuroprotective agents via inducing a mild mitochondrial depolarization. Copyright © 2012 John Wiley & Sons, Ltd. |
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Keywords: | mitochondrial calcium mitochondrial membrane potential calcium mitochondria Citrus |
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