Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA.
Chem Res Toxicol. 2012 Aug 20;25(8):1574-80. doi: 10.1021/tx2005025. Epub 2012 Aug 9.
Ginseng has long been used in Asian countries for more than 2000 years. Currently, in the "Western World or Western Medicines", many reports have indicated that they have used herbal medicines, and ginseng is one of the most popular herbs. Several recent reports have indicated that the antioxidant/antioxidative stress activities of ginseng play a role in the benefits of ginseng; however, the precise mechanism is lacking. The antioxidant response element (ARE) is a critical regulatory element for the expression of many antioxidant enzymes and phase II/III drug metabolizing/transporter genes, mediated by the transcription factor nuclear factor (erythroid-derived 2)-like 2 (Nrf2). The aim of this study was to examine the potential activation and synergism of Nrf2-ARE-mediated transcriptional activity between three common ginsenosides present in ginseng, ginsenoside Rb1 (Rb1), ginsenoside Rg1 (Rg1), and ginsenoside 20(S)-protopanaxatriol (20S). We tested whether these ginsenosides and their combinations could induce Nrf2-ARE activities in HepG2-C8 cells with stably transfected ARE luciferase reporter gene. Cell proliferation, antioxidant and ARE activities, Western blotting of Nrf2 protein, and qPCR of mRNA of Nrf2 were conducted for Rb1, Rg1, and 20S as well as the combinations of 20S with Rb1 or Rg1. To determine the combination effects, the combination index (CI) was calculated. Rb1 and Rg1 are relatively nontoxic to the cells, while 20S at 50 μM or above significantly inhibited the cell proliferation. Rb1, Rg1, or 20S induced total antioxidant activity and ARE activity in a concentration-dependent manner. Furthermore, combinations of 20S with either Rb1 or Rg1 induced total antioxidant and ARE activity synergistically. The induction of Nrf2 protein and mRNA was also found to be synergistic with the combination treatments. In summary, in this study, we show that ginsenosides Rb1, Rg1, and 20S possess antioxidant activity, transcriptionally activating ARE as well as the potential of synergistic activities. The Nrf2-ARE-mediated antioxidant pathway could play a role for the overall antioxidative stress activities, which could be important for ginseng's health beneficial effects such as cancer chemopreventive activities.
人参在亚洲国家已经使用了 2000 多年。目前，在“西方世界或西药”中，许多报告表明他们已经使用了草药，而人参是最受欢迎的草药之一。最近有几项报告表明，人参的抗氧化/抗氧化应激活性在人参的益处中发挥作用；然而，确切的机制尚不清楚。抗氧化反应元件（ARE）是许多抗氧化酶和 II 期/III 期药物代谢/转运基因表达的关键调节元件，由转录因子核因子（红系衍生 2）样 2（Nrf2）介导。本研究旨在研究人参中三种常见人参皂苷（人参皂苷 Rb1（Rb1）、人参皂苷 Rg1（Rg1）和人参皂苷 20(S)-原人参三醇（20S））之间 Nrf2-ARE 介导的转录活性的潜在激活和协同作用。我们测试了这些人参皂苷及其组合是否可以在稳定转染 ARE 荧光素酶报告基因的 HepG2-C8 细胞中诱导 Nrf2-ARE 活性。进行了 Rb1、Rg1 和 20S 以及 20S 与 Rb1 或 Rg1 的组合对细胞增殖、抗氧化和 ARE 活性、Nrf2 蛋白的 Western 印迹和 Nrf2 mRNA 的 qPCR。为了确定组合效应，计算了组合指数（CI）。Rb1 和 Rg1 对细胞相对无毒，而 20S 在 50 μM 或更高浓度时显著抑制细胞增殖。Rb1、Rg1 或 20S 以浓度依赖性方式诱导总抗氧化活性和 ARE 活性。此外，20S 与 Rb1 或 Rg1 的组合还协同诱导总抗氧化和 ARE 活性。还发现 Nrf2 蛋白和 mRNA 的诱导也与联合处理协同。总之，在这项研究中，我们表明人参皂苷 Rb1、Rg1 和 20S 具有抗氧化活性，转录激活 ARE 以及协同作用的潜力。Nrf2-ARE 介导的抗氧化途径可能在整体抗氧化应激活性中发挥作用，这对于人参的健康有益作用（如癌症化学预防作用）可能很重要。
