The aim of this study was to investigate the protective effects of 6-shogaol on tert-butyl hydroperoxide (tBHP)-induced oxidative stress leading to apoptosis in human hepatoma cell line HepG2. The cells were exposed to tBHP (100 μmol/l) after pretreatment with 6-shogaol (2.5 and 5 μmol/l), and then cell viability was measured. 6-Shogaol fully prevented HepG2 cell death caused by tBHP. Treatment of tBHP resulted in apoptotic cell death as assessed by TUNEL assay and the expression of apoptosis regulator proteins, Bcl-2 family, caspases and cytochrome c. Cells treated with 6-shogaol showed rapid reduction of apoptosis by restoring these markers of apoptotic cells. In addition, 6-shogaol significantly recovered disruption of mitochondrial membrane potential as a start sign of hepatic apoptosis induced by oxidative stress. In line with this observation, antioxidative 6-shogaol inhibited generation of reactive oxygen species and depletion of reduced glutathione in tBHP-stimulated HepG2 cells. Taken together, these results for the first time showed antioxidative and antiapoptotic activities of 6-shogaol in tBHP-treated hepatoma HepG2 cells, suggesting that 6-shogaol could be beneficial in hepatic disorders caused by oxidative stress.

Keywords:
6-Shogaol, Tert-butyl hydroperoxide, Apoptosis, Mitochondrial membrane potential, Reactive oxygen species
1.
Castro L, Freeman BA: Reactive oxygen species in human health and disease. Nutrition 2001;17:161-165.
2.
Al-Gubory KH: Mitochondria: omega-3 in the route of mitochondrial reactive oxygen species. Int J Biochem Cell Biol 2012;44:1569-1573.
3.
Haidara K, Morel I, Abalea V, Gascon-Barré M, Denizeau F: Mechanism of tert-butylhydroperoxide induced apoptosis in rat hepatocytes: involvement of mitochondria and endoplasmic reticulum. Biochim Biophys Acta 2002;1542:173-185.
4.
Kroemer G, Galluzzi L, Brenner C: Mitochondrial membrane permeabilization in cell death. Physiol Rev 2007;87:99-163.
5.
Ricci JE, Gottlieb RA, Green DR: Caspase-mediated loss of mitochondrial function and generation of reactive oxygen species during apoptosis. J Cell Biol 2003;160:65-75.
6.
Fruehauf JP, Meyskens FL Jr: Reactive oxygen species: a breath of life or death? Clin Cancer Res 2007;13:789-794.
7.
Martín C, Martínez R, Navarro R, Ruiz-Sanz JI, Lacort M, Ruiz-Larrea MB: Tert-Butyl hydroperoxide-induced lipid signaling in hepatocytes: involvement of glutathione and free radicals. Biochem Pharmacol 2001;62:705-712.
8.
Nishida K, Ohta Y, Ishiguro I: Modulating role of endogenous reduced glutathione in tert-butyl hydroperoxide-induced cell injury in isolated rat hepatocytes. Free Radic Biol Med 1997;23:453-462.
9.
Piret JP, Arnould T, Fuks B, Chatelain P, Remacle J, Michiels C: Mitochondria permeability transition-dependent tert-butyl hydroperoxide-induced apoptosis in hepatoma HepG2 cells. Biochem Pharmacol 2004;67:611-620.
10.
Tripathi M, Singh BK, Kakkar P: Glycyrrhizic acid modulates t-BHP induced apoptosis in primary rat hepatocytes. Food Chem Toxicol 2009;47:339-347.
11.
López-Reyes AG, Arroyo-Curras N, Cano BG, Lara-Díaz VJ, Guajardo-Salinas GE, Islas JF, Morales-Oyarvide V, Morales-Garza LA, Galvez-Gastelum FJ, Grijalva G, Moreno-Cuevas JE: Black bean extract ameliorates liver fibrosis in rats with CCl4-induced injury. Ann Hepatol 2008;7:130-135.
12.
Wang YP, Cheng ML, Zhang BF, Mu M, Wu J: Effects of blueberry on hepatic fibrosis and transcription factor Nrf2 in rats. World J Gastroenterol 2010;16:2657-2663.
13.
Afzal M, Al-Hadidi D, Menon M, Pesek J, Dhami MS: Ginger: An ethnomedical, chemical and pharmacological review. Drug Metabol Drug Interact 2001;18:159-190.
14.
Govindarajan VS: Ginger-chemistry, technology, and quality evaluation: part 1. Crit Rev Food Sci Nutr 1982;17:1-96.
15.
Wu H, Hsieh MC, Lo CY, Liu CB, Sang S, Ho CT, Pan MH: 6-shogaol is more effective than 6-gingerol and curcumin in inhibiting 12-O-tetradecanoylphorbol 13-acetateinduced tumor promotion in mice. Mol Nutr Food Res 2010;54:1296-1306.
16.
Peng F, Tao Q, Wu X, Dou H, Spencer S, Mang C, Xu L, Sun L, Zhao Y, Li H, Zeng S, Liu G, Hao X: Cytotoxic, cytoprotective and antioxidant effects of isolated phenolic compounds from fresh ginger. Fitoterapia 2012;83:568-585.
17.
Dugasani S, Pichika MR, Nadarajah VD, Balijepalli MK, Tandra S, Korlakunta JN: Comparative antioxidant and anti-inflammatory effects of [6]-gingerol, [8]-gingerol, [10]-gingerol and [6]-shogaol. J Ethnopharmacol 2010;127:515-520.
18.
Bak MJ, Ok S, Jun M, Jeong WS: 6-shogaol-rich extract from ginger up-regulates the antioxidant defense systems in cells and mice. Molecules 2012;17:8037-8055.
19.
Weng CJ, Wu CF, Huang HW, Ho CT, Yen GC: Anti-invasion effects of 6-shogaol and 6-gingerol, two active components in ginger, on human hepatocarcinoma cells. Mol Nutr Food Res 2010;54:1618-1627.
20.
Harada H, Grant S: Apoptosis regulators. Rev Clin Exp Hematol 2003;7:117-138.
21.
Caroppi P, Sinibaldi F, Fiorucci L, Santucci R: Apoptosis and human diseases: mitochondrion damage and lethal role of released cytochrome C as proapoptotic protein. Curr Med Chem 2009;16:4058-4065.
22.
Bratton SB, Salvesen GS: Regulation of the Apaf-1-caspase-9 apoptosome. J Cell Sci 2010;123:3209-3214.
23.
Garrido C, Galluzzi L, Brunet M, Puig PE, Didelot C, Kroemer G: Mechanisms of cytochrome c release from mitochondria. Cell Death Differ 2006;13:1423-1433.
24.
Estaquier J, Vallette F, Vayssiere JL, Mignotte B: The mitochondrial pathways of apoptosis. Adv Exp Med Biol 2012;942:157-183.
25.
Waterhouse NJ, Goldstein JC, von Ahsen O, Schuler M, Newmeyer DD, Green DR: Cytochrome c maintains mitochondrial transmembrane potential and ATP generation after outer mitochondrial membrane permeabilization during the apoptotic process. J Cell Biol 2001;153:319-328.
26.
Zhao K, Luo G, Giannelli S, Szeto HH: Mitochondria-targeted peptide prevents mitochondrial depolarization and apoptosis induced by tert-butylhydroperoxide in neuronal cell lines. Biochem Pharmacol 2005;70:1796-1806.
27.
Nieminen AL, Byrne AM, Herman B, Lemasters JJ: Mitochondrial permeability transition in hepatocytes induced by t-BuOOH: NAD(P)H and reactive oxygen species. Am J Physiol 1997;272:C1286-C1294.
28.
Kanupriya, Prasad D, Sai Ram M, Sawhney RC, Ilavazhagan G, Banerjee PK: Mechanism of tert-butylhydroperoxide induced cytotoxicity in U-937 macrophages by alteration of mitochondrial function and generation of ROS. Toxicol In Vitro 2007;21:846-854.
29.
Meyer AJ, Hell R: Glutathione homeostasis and redox-regulation by sulfhydryl groups. Photosynth Res 2005;86:435-457.
30.
Pan MH, Hsieh MC, Kuo JM, Lai CS, Wu H, Sang S, Ho CT: 6-Shogaol induces apoptosis in human colorectal carcinoma cells via ROS production, caspase activation, and GADD 153 expression. Mol Nutr Food Res 2008;52:527-537.
31.
Hu R, Zhou P, Peng YB, Xu X, Ma J, Liu Q, Zhang L, Wen XD, Qi LW, Gao N, Li P: 6-Shogaol induces apoptosis in human hepatocellular carcinoma cells and exhibits anti-tumor activity in vivo through endoplasmic reticulum stress. PLoS One 2012;7:e39664.
© 2014 S. Karger AG, Basel
2014
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.