Chang Kuei-Ting, Lii Chong-Kuei, Tsai Chia-Wen, Yang Ai-Jen, Chen Haw-Wen
Department of Nutrition, Chung Shan Medical University, Taichung, Taiwan.
Food Chem Toxicol. 2008 Mar;46(3):1079-88. doi: 10.1016/j.fct.2007.11.002. Epub 2007 Nov 13.
Andrographis paniculata (Ap) is a commonly used herb for traditional medicine in many Southeast Asian countries. In the present study, we investigated the effect of Ap on the expression of the pi class of glutathione S-transferase (GSTP) in rat primary hepatocytes. Hepatocytes were treated with 25 or 50 microg/mL of ethanol or ethyl acetate extracts of Ap (ApEE or ApEAE) or 10 or 20 microM andrographolide, which is the major active diterpene lactone of Ap, for 48 h. ApEE, ApEAE, and andrographolide dose-dependently induced GSTP protein and mRNA expression. In a GST activity assay, GST activity was significantly higher in cells treated with the maximum concentrations of ApEE, ApEAE, and andrographolide than in control cells (P<0.05). The pTA-2713 luciferase reporter construct containing rat GSTP enhancer 1 (GPE1) was transiently transfected into Clone 9 liver cells. Cells treated with ApEE, ApEAE, and andrographolide showed a dose-dependent increase in luciferase activity. GPE1 deletion abolished the induction efficiency of Ap. Also, the induction of GSTP expression by Ap was inhibited by wortmannin, which is an inhibitor of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway. These results indicate that ApEE, ApEAE, and andrographolide induce GSTP expression. This induction is likely related to the PI3K/Akt pathway, and GPE1, an enhancer element in GSTP promoter, is essential for the induction.
穿心莲是许多东南亚国家传统医学中常用的草药。在本研究中，我们调查了穿心莲对大鼠原代肝细胞中谷胱甘肽S-转移酶（GSTP）π类表达的影响。用25或50微克/毫升的穿心莲乙醇提取物（ApEE）或乙酸乙酯提取物（ApEAE）或10或20微摩尔的穿心莲内酯（穿心莲的主要活性二萜内酯）处理肝细胞48小时。ApEE、ApEAE和穿心莲内酯呈剂量依赖性地诱导GSTP蛋白和mRNA表达。在GST活性测定中，用ApEE、ApEAE和穿心莲内酯最大浓度处理的细胞中GST活性显著高于对照细胞（P<0.05）。将含有大鼠GSTP增强子1（GPE1）的pTA-2713荧光素酶报告构建体瞬时转染到Clone 9肝细胞中。用ApEE、ApEAE和穿心莲内酯处理的细胞显示荧光素酶活性呈剂量依赖性增加。GPE1缺失消除了穿心莲的诱导效率。此外，wortmannin（磷脂酰肌醇3-激酶（PI3K）/Akt途径的抑制剂）抑制了穿心莲对GSTP表达的诱导。这些结果表明，ApEE、ApEAE和穿心莲内酯诱导GSTP表达。这种诱导可能与PI3K/Akt途径有关，并且GSTP启动子中的增强子元件GPE1对于诱导至关重要。
