Abstract
Recent studies revealed that the herb Andrographis paniculata possesses cardioprotective activities. Using neonatal rat cardiomyocytes, the cardioprotective actions of several diterpene lactones derived from A. paniculata including andrographolide, 14-deoxyandrographolide, 14-deoxy-11,12-didehydroandrographolide, and sodium 14-deoxyandrographolide-12-sulfonate were investigated. Pretreatment with andrographolide but not with the other compounds protected the cardiomyocytes against hypoxia/ reoxygenation injury and up-regulated the cellular-reduced glutathione (GSH) level and antioxidant enzyme activities. The cardioprotective action of andrographolide was found to coincide in a time-dependent manner with the up-regulation of GSH, indicating the important role of GSH. The cardioprotective action of andrographolide was also completely abolished by buthionine sulfoximine, which acts as a specific γ-glutamate cysteine ligase (GCL) inhibitor to deplete cellular GSH level. It was subsequently found that the mRNA and protein levels of the GCL catalytic subunit (GCLC) and modifier subunit (GCLM) were up-regulated by andrographolide. Luciferase reporter assay also demonstrated that andrographolide activated both the GCLC and the GCLM promoters in the transfected rat H9C2 cardiomyocyte cell line. The 12-O-tetradecanoylphorbo-13-acetate response element or the antioxidant response element may be involved in the transactivating actions of andrographolide on the GCLC and GCLM promoters. The present study pinpoints andrographolide as a cardioprotective principle in A. paniculata and reveals its cytoprotective mechanism.
Footnotes
This study was supported by Direct Grants and also by a Strategic Investments Scheme from The Chinese University of Hong Kong.
A.Y.H.W. is supported by the National Institute of Aging, National Institutes of Health.
Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
doi:10.1124/jpet.107.133918.
ABBREVIATIONS:AP, Andrographis paniculata; NRC, neonatal rat cardiomyocyte; H/R, hypoxia/reoxygenation; DMEM, Dulbecco's modified Eagle's medium; LDH, lactate dehydrogenase; SOD, superoxide dismutase; GPX, glutathione peroxidase; GR, glutathione reductase; GSSG, oxidized glutathione; GSH, reduced glutathione; PCR, polymerase chain reaction; GCL, γ-glutamate-cysteine ligase; GCLC, γ-glutamate-cysteine ligase catalytic subunit; GCLM, γ-glutamate-cysteine ligase modulatory subunit; EMSA, electrophoretic mobility shift assay; BSO, buthionine sulfoximine; ATA, 3-amino-1,2,4-triazole; NF, nuclear factor; TRE, 12-O-tetradecanoylphorbo-13-acetate response element; AP-1, activator protein-1; ARE, antioxidant response element; Nrf, NF-E2-related factor; ROS, reactive oxygen species; H2O2, hydrogen peroxide; NQO, NAD(P)H:quinone oxidoreductase.
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- Received November 3, 2007.
- Accepted January 2, 2008.
- The American Society for Pharmacology and Experimental Therapeutics
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