Traditional Chinese medicinal formula Si-Wu-Tang prevents oxidative damage by activating Nrf2-mediated detoxifying/antioxidant genes

Mandy Liu,Zhong Zuo,Zhijun Wang,Bradley Andresen,Sunil Prabhu,Ranadheer Ravula,Ying Huang,Arvind Thakkar,Moses Ss Chow

doi:10.1186/2045-3701-4-8

Mandy Liu, Zhong Zuo + Show 7 more

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https://doi.org/10.1186/2045-3701-4-8

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Abstract

BackgroundInduction of Nrf2-mediated detoxifying/antioxidant genes has been recognized as an effective strategy for cancer chemoprevention. Si-Wu-Tang (SWT), comprising the combination of four herbs, Paeoniae, Angelicae, Chuanxiong and Rehmanniae, is one of the most popular traditional oriental medicines for women’s diseases. The purpose of this study is to determine the effects of SWT on Nrf2 pathway in vitro and in vivo and to identify the active component(s).ResultsCell viability and apoptosis were analyzed in the non-cancerous breast epithelial cell line MCF-10A after H2O2 treatment in the presence or absence of SWT using the Sulphorhodamine B assay, Annexin-V/Propidium iodide staining and flow cytometry. SWT strongly reduced H2O2 -induced cytotoxicity and apoptosis in MCF-10A cells. Expression of Nrf2 and Nrf2-regulated genes HMOX1 (heme oxygenase 1) and SLC7A11 (xCT) was evaluated by quantitative RT-PCR, Western Blot and immunocytochemistry. SWT strongly induced Nrf2-regulated genes at mRNA and protein levels and increased the nuclear translocation of Nrf2 in MCF-10A cells. The in vivo pharmacodynamic effect of SWT was evaluated in healthy female Sprague–Dawley rats. Short-term oral administration of SWT (1,000 mg/kg per day for six consecutive days) to rats resulted in an increased expression of Nrf2-regulated genes Hmox1 and Slc7A11 in the liver detected by quantitative RT-PCR. Among nine compounds that have been identified previously in the SWT products, z-liguistilide was discovered as the main component responsible for the effect of Nrf2 activation using the antioxidant response element-luciferase reporter gene assay. Z-liguistilide was confirmed with a high potency to induce Nrf2-regulated genes and Nrf2 nuclear translocation.ConclusionsOur results demonstrated that SWT and its component z-liguistilide are able to activate the Nrf2 pathway in non-cancerous cells and organs in vitro and in vivo, suggesting that SWT might be an orally effective and nontoxic agent for cancer chemoprevention.

Highlights

Induction of nuclear factor erythroid 2 -related factor 2 (Nrf2)-mediated detoxifying/antioxidant genes has been recognized as an effective strategy for cancer chemoprevention
Protective effects of SWT against hydrogen peroxide (H2O2) – induced cytotoxicity The MCF-10A cells were pre-treated with SWT extract for 2 hours before adding H2O2 and were incubated for additional 24 hours
In the presence of increasing concentrations of SWT (1.28, 2.56 and 4.0 mg/mL), the IC50s of H2O2 were increased from 0.13 ± 0.0006 mM to 0.15 ± 0.004, 0.18 ± 0.006 and 0.19 ± 0.013 mM, respectively (Figure 1A)

Summary

Introduction

Induction of Nrf2-mediated detoxifying/antioxidant genes has been recognized as an effective strategy for cancer chemoprevention. Protection of normal cells from a diversity of such events through induction of the detoxifying and antioxidant proteins is one of the promising strategies to prevent cancer and other chronic diseases [10]. This is a attractive strategy for breast cancer prevention, because exposure to carcinogens, including metabolites of endogenous and exogenous estrogens, play a significant role in the development of breast cancer through the cumulative accumulation of mutagenic events over a women’s lifetime [11]

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