Active constituents
The major lignan in chaparral, known as nordihydroguaiaretic acid (NDGA) is a potent anti-oxidant and was thought by some scientists to be a potential cancer treatment. In a rat study, NDGA and a leaf extract of a South American subspecies of chaparral were found to exert an antitumor effect.4 However, one report suggests that NDGA may stimulate further growth of tumours in cancer patients.5 Clinical trials, therefore, are still needed to establish whether chaparral is a safe and effective treatment for people with cancer.
Other reported effects for chaparral include anti-inflammatory properties6 7 as well as antimicrobial actions in test tubes.8 These actions have note been established in human clinical trials
References
1. Brinker F. Larrea tridentata (D.C.) Coville (chaparral or creosote bush). Br J Phytother 1993/1994;3:10–31 [review].
2. Moore M. Medicinal Plants of the Desert and Canyon West. Santa Fe: Museum of New Mexico Press, 1989, 27–9.
3. Kay MA. Healing with Plants in the American and Mexican West. Tucson: University of Arizona Press, 1996, 178–81.
4. Birkenfeld S, Zaltsman YA, Krispin M, et al. Antitumor effects of inhibitors of arachadonic acid cascade on experimentally induced intestinal tumors. Dis Colon Rectum 1987;30:43–6.
5. Smart CR, Hogle CR, Vogel H, et al. Clinical experience with nordihydroguaiaretic acid—”chapparel tea” [sic] in the treatment of cancer. Rocky Mtn Med J 1970;67:39–43.
6. Bokoch G, Reed P. Evidence for inhibition of leukotriene A4 synthesis by 5,8,11,14-eicosatetraynoic acid in guinea pig polymorphonuclear leukocytes. J Biol Chem 1981;256:4156.
7. Salari H, Braquet P, Borgeat P. Comparative effects of indomethacin, acetylenic acids, 15-HETE, nordihydroguaiaretic acid and BW755C on the metabolism of arachidonic acid in human leukocytes and platelets. Prostaglan Leukot Med 1984;13:53–60.
8. Calzado-Flores C, Segura-Luna JJ, Guajardo-Touche EM. Effects of chaparrin, nordihydroguaiaretic acid and their structural analogues on Entamoeba histolytica cultures. Proc West Pharmacol Soc 1995;38:105–6.
9. Kay MA. Healing with Plants in the American and Mexican West. Tucson: University of Arizona Press, 1996, 178–81.
10. Moore M. Medicinal Plants of the Desert and Canyon West. Santa Fe: Museum of New Mexico Press, 1989, 27–9.
11. Sheikh NM, Philen RM, Love LA. Chaparral-associated hepatotoxicity. Arch Int Med 1997;157:913–9.
12. Smart CR, Hogle CR, Vogel H, et al. Clinical experience with nordihydroguaiaretic acid—”chapparel tea” [sic] in the treatment of cancer. Rocky Mtn Med J 1970;67:39–43.
13. McGuffin M, Hobbs C, Upton R, Goldberg A. American Herbal Products Association’s Botanical Safety Handbook. Boca Raton, FL: CRC Press, 1997, 67.

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