Chaparral, is a tough plant with a long history of medicinal use by the native peoples of North America. Traditionally, it was taken internally to treat joint pain and to eliminate worms. Chaparral tea was applied externally to painful joints and minor wounds, and also used as a mouthwash and hair rinse. When European herbalists encountered chaparral, they initially used it to treat colds, flus, and intestinal infections. Later, based on a number of unsubstantiated cases, chaparral gained a reputation as a miracle cancer cure.
Note : There are a number of reports in which it appears that internal use of chaparral has caused serious liver injury. See Safety Issues for more information.
There are no scientifically established medicinal uses of chaparral, and reports of liver injury have made it substantially less popular in recent years.
The presumed active ingredient in chaparral is the antioxidant compound nordihydroguaiaretic acid (NDGA). NDGA is used as a preservative in packaged and processed foods. Some evidence from animal and test tube studies hints that NGDA, or synthetic chemicals related to it, might have anticancer effects. 1-4 However, the same can be said of thousands of substances. So far, NGDA and its analogues have not shown themselves promising enough to warrant human trials.
Other proposed actions of chaparral and its constituents lack more than the most minimal of scientific evidence. These include anti-inflammatory, anti-microbial, and liver-protective effects.
We do not recommend using chaparral internally.
For external use, chaparral may be prepared as a tea or allowed to diffuse its contents into oil over several days or weeks. The resulting preparation is then applied in the form of a wet or oil-soaked cloth.
Considerable confusion exists regarding the safety of chaparral. Chaparral itself does not appear to be toxic even when given to animals in very high doses. 7,8 In particular, it does not appear to contain any liver toxins. Nonetheless, there have been recurrent reports of severe liver or kidney injury associated with use of the herb. 5,6 While in some of these cases cause and effect was poorly established, in others the connection seems clear.
Almost all reports involved chaparral tablets or extracts rather than the more traditional tea; however, the significance of this distinction is not clear. It is quite likely, though not proven, that liver or kidney toxicity chaparral is an “idiosyncratic reaction,” something in the nature of a rare allergy. However, until this situation is cleared up, internal use of chaparral must regarded as presenting unknown risks. Since chaparral has no established benefits as yet, it is probably best to simply avoid it.
2. Zavodovskaya M, Campbell MJ, Maddux BA, et al. Nordihydroguaiaretic acid (NDGA), an inhibitor of the HER2 and IGF-1 receptor tyrosine kinases, blocks the growth of HER2-overexpressing human breast cancer cells. J Cell Biochem. 2007 Jun 11. [Epub ahead of print]
3. Meyer GE, Chesler L, Liu D, et al. Nordihydroguaiaretic acid inhibits insulin-like growth factor signaling, growth, and survival in human neuroblastoma cells. J Cell Biochem. 2007 May 7. [Epub ahead of print]
4. Chen JH, Yao XH, Gong W, et al. A novel lipoxygenase inhibitor Nordy attenuates malignant human glioma cell responses to chemotactic and growth stimulating factors. J Neurooncol. 2007 Mar 22. [Epub ahead of print]
Last reviewed December 2015 by EBSCO CAM Review Board
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