July 1 2007 post. A friend recently sent me a 2005 study by an MD Anderson research team on plant polyphenols and chemosensitization, which I am going through bit by bit. The bit I looked at yesterday concerns an active component of Turkey Rhubarb (scientific name: Rheum palmatum) called emodin. By the way, the roots and rhizomes of this plant have been used in traditional Chinese and Japanese medicine for centuries. And its extract, emodin, has many medicinal properties; for instance, it is antiaggregant, anti-inflammatory, antimutagenic, antiseptic, antitumour, antiviral, cathartic, cytotoxic, purgative, immunosuppressive, antispasmodic, styptic and viricidal!
The abstract of the above-mentioned MD Anderson study can be seen at: http://tinyurl.com/2k3pea The full study reports that emodin may sensitize cancer cells to chemotherapy, and also kills human promyeloleukemic HL-60 cells in vitro. The MD Anderson researchers examined the effects of emodin on a variety of cancers, from lung to breast cancer, but I found no mention of MM.
So does this extract have any connection to MM? You betcha! A quick online search took me to the March 2007 issue of Molecular Cancer Therapeutics, which features a study titled: Emodin has a cytotoxic activity against human multiple myeloma as a Janus-activated kinase 2 inhibitor (http://tinyurl.com/38a7om). I wanted to understand what Janus-activated kinase 2, or JAK2, meant, so I looked it up and found the following study: http://tinyurl.com/225l93, according to which IL-6 and the subsequent JAK- dependent signaling pathways are essential for MM cell proliferation. Okay, so anything that inhibits that process is absolutely brilliant! Back to the Molecular Cancer Therapeutics abstract. It concludes that emodin inhibits interleukin-6 â‚¬”induced JAK2/STAT3 pathway selectively and induces apoptosis in myeloma cells via down-regulation of Mcl-1, which is a good target for treating myeloma. Taken together, our results show emodin as a new potent anticancer agent for the treatment of multiple myeloma. This all sounds very promising. I just hope more studies are done on this compound, as well as on many others!
According to a few herbal websites, rhubarb root has been used for two thousand years as a gentle but effective laxative. It cleanses, and also treats constipation, but â‚¬”when taken in smaller doses â‚¬”can also relieve diarrhea and hemorrhoids. Quite remarkable. However, a word of caution. I read warnings against munching on or cooking and eating this plant’s leaves, which are extremely toxic. Only the roots and rhizomes are used for medicinal purposes. I thought I should mention this, in case anybody was vaguely thinking of preparing some rhubarb leaf tea. Not a good idea! However, the leaves come in handy if you want to prepare an organic insecticide, for instance to fight those pesky aphids that infest your rose bushes (sigh!). For some useful suggestions, including how to use rhubarb leaves to clean burnt pots and pans (no kidding), go to: http://www.rhubarbinfo.com/rhubarb-uses.html This website also includes a rhubarb tart song and rhubarb limericks.
Other emodin-cancer studies:
- the previously-mentioned promyeloleukemic HL-60 cell abstract was published in December 2002 in Biochemical Pharmacology : http://tinyurl.com/34xm94
- another study on HL-60 cells, titled: Aloe-emodin induced in vitro G2/M arrest of cell cycle in human promyelocytic leukemia HL-60 cells (http://tinyurl.com/3xn8fp), was published in 2004 in Food and Chemical Toxicology
- a study on human oral cancer and emodin was published in Oral Oncology in January 2007: http://tinyurl.com/2mp5rp
- a hepatocellular carcinoma (HCC) study: http://tinyurl.com/3d6d52, Life Sciences, 2004. This particular study is interesting because it shows that emodin activates the tumor-suppressor p53, also known as tumour protein p53, or TP53, which I have mentioned in previous posts. Go, p53!
- a study on Merkel cell carcinoma and aloe-emodin: http://tinyurl.com/2p4jj5, published in Oncology Reports in 2004
- a study titled Emodin Enhances Arsenic Trioxide-Induced Apoptosis via Generation of Reactive Oxygen Species and Inhibition of Survival Signaling (http://tinyurl.com/34ockb), published in Cancer Research in 2004.