Emodin exhibits antibacterial, anti-viral and anti-inflammatory strengths; but the real interest comes in its activities against the spike protein of coronavirus and against cancer metastasis and cancer stem cells.
What is Emodin?
Emodin (6-methyl-1,3,8-trihydroxyanthraquinone) is a member of the anthraquinone family, usually isolated from rheum, (rhubarb), buckthorn and Japanese knotweed, although it is present in good levels in more than 20 plants and has been used in Traditional Chinese Medicine for over 2000 years. It may be used as aloe-emodin.
It is used as an antioxidant, and has antibacterial activity especially with Bacillus subtilis, Staphylococcus aureus, Enterococcus faecium (1) and M. tuberculosis, though not with E coli or Klebsiella.
Importantly, it has antiviral activity and has shown dose-dependent abilities in SARS-Covid-1 when used as a major part of the TCM antiviral medicine Lianhua Qingwen. As long ago as 2007, Emodin was shown to block the coronavirus spike protein (2)
Emodin is also used as an anti-inflammatory, a laxative and has significant anti-cancer properties. Several studies have shown it can block the formation of amyloid plaque in the brain, crucial to Alzheimer’s. A 2019 study showed it rescued rats after high homocysteine-induced dementia (3).
However, if used for a long period and/or in high doses it can cause liver and kidney toxicity.
Anti-cancer activity of Emodin
We first came across Emodin at CANCERactive more than 18 years ago when covering Join Boik of MD Anderson, who had written a book entitled ‘Natural compounds in Cancer Therapy’ from which we produced a list of 20. Emodin was one of these, with the article (4) stating that Emodin was ‘Shown to be a powerful anti-cancer agent against lung cancer, pancreatic cancer, colon cancer and liver cancer. It is also known to make the Liver cancer drug Sorafenib work better’.
In the past 20 years, yet more discoveries have been made (1).
Cancer cell and cancer stem cell death
Emodin blocked growth, cell proliferation and caused apoptosis in cancer cell lines of bladder and breast cancers.
It also blocked cancer stem cell pathways Notch1, β-catenin and STAT3 in glioma cells and Wnt pathways in a number of cancers including colorectal cancer (5).
It blocked metastasis to the lungs in breast cancer. The researchers noted ‘The natural compound Emodin blocks the tumor-promoting feed forward interactions between cancer cells and macrophages, and thus ameliorates the immunosuppressive state of the tumor microenvironment' (6).
Metastasis is also restricted by Emodin's effects on cell migration and invasion by inhibiting the β-catenin and Akt pathways.
It also seems to make drugs work better and for longer – for example there is research on its use with Cisplatin in ovarian cancer.
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* Helpful links
Go to: 20 natural compounds that fight cancer
* References
- Nature October 2017; Chlorinated emodin as a natural antibacterial agent
- Emodin blocks the SARS coronavirus spike protein
- Int J Neuropsychophamacol; 2019 Jan1; Peng Zeng et al. Emodin Rescued Hyperhomocysteinemia-Induced
- 20 cancer beating natural compounds; CANCERactive
- Stem Cells Dev, Sep 27, 2014; Jeongyub Kim et al; Emodin reduces maintenance of Stemness
- Emodin reduces breast cancer lung metastasis: Theranostics 2020; 10 (18) July. Qing Liu et al;