Nordihydroguaiaretic acid/NDGA

Related Terms

1 aryl tetralin lignans, chaparral taxa, chaparral tea, chaparro, creosote, creosote bush, dwarf evergreen oak, el gobernadora (Spanish), falsa alcaparra (Spanish), flavonoids, furanoid lignans, geroop, gobernadora, greasewood, guaiaretic acid, guamis, gumis, hediondilla, hideonodo, hydrocarbons, jarillo, kovanau, kreosotstrauch, larrea, Larrea divaricata, Larrea glutiosa, Larrea mexicana, Larrea mexicana Moric, Larrea tridentate, Larrea tridentata (DC) Coville, lignans, maltose-M3N, M4N, NDGA, nordihydroguaiaretic acid, Nordy, palo ondo (Spanish), sapogenins, shoegoi, sonora covillea, sterols, tasago, triterpenes, volatile oils, wax esters, ya-tmep, yah-temp, Zygophyllaceae (family).

Background

Chaparral is a shrub found in the desert regions of southwestern United States and Mexico. It was used by Native American populations for indications including chicken pox (varicella), colds, diarrhea, menstrual cramps, pain, rheumatic diseases, skin disorders, snake bites, and as an emetic. Chaparral tea was also used for purported effects of removing lysergic acid diethylamide (LSD) residue and thereby preventing recurrent hallucinations. Chaparral leaves have also been used externally for bruises, scratches, wounds, and hair growth.
The chaparral component nordihydroguaiaretic acid (NDGA) has been evaluated as a treatment for cancer but, due to risk of toxicity, it is considered unsafe and not recommended for use.

Evidence Table

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. GRADE *
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. GRADE *


Chaparral and one of its components called nordihydroguaiaretic acid (NDGA) have antioxidant ("free-radical scavenging") properties and have been proposed as cancer treatments. However, chaparral and NDGA have been linked with cases of kidney and liver failure, liver cirrhosis, kidney cysts, and kidney cancer in humans. In response to these reports, the U.S. Food and Drug Administration (FDA) removed chaparral from its "Generally Recognized as Safe" (GRAS) list in 1970. Chaparral and NDGA are generally considered unsafe and are not recommended for use.

 C


Chaparral and one of its components called nordihydroguaiaretic acid (NDGA) have antioxidant ("free-radical scavenging") properties and have been proposed as cancer treatments. However, chaparral and NDGA have been linked with cases of kidney and liver failure, liver cirrhosis, kidney cysts, and kidney cancer in humans. In response to these reports, the U.S. Food and Drug Administration (FDA) removed chaparral from its "Generally Recognized as Safe" (GRAS) list in 1970. Chaparral and NDGA are generally considered unsafe and are not recommended for use.

 C
* Key to grades

A: Strong scientific evidence for this use
B: Good scientific evidence for this use
C: Unclear scientific evidence for this use
D: Fair scientific evidence for this use (it may not work)
F: Strong scientific evidence against this use (it likley does not work)
* Key to grades

A: Strong scientific evidence for this use
B: Good scientific evidence for this use
C: Unclear scientific evidence for this use
D: Fair scientific evidence for this use (it may not work)
F: Strong scientific evidence against this use (it likley does not work)

Tradition / Theory

The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.

Dosing

Adults (18 years and older)
Safety has not been established for any dose. Small doses of tea have been used; for example, 1 teaspoon of chaparral leaves and flowers steeped in 1 pint of water for 15 minutes, consumed 1-3 cups daily for up to a maximum of several days. Chaparral tea has also been made by steeping 7-8 grams of crumbled dried leaves, stems, and twigs in one quart of hot water. As a water extract, chaparral might be consumed in the amount of one to three cups of chaparral tea per day for a period of two to three weeks, although this is not recommended.
A tincture has also been used; for example, 20 drops up to three times daily. These preparations may be associated with less toxicity, and possibly contain fewer allergenic compounds than capsules or tablets. Oil or powder forms of chaparral have also been used, applied to an affected area of skin several times daily.
Capsules or tablets may deliver large doses leading to toxicity, and are not recommended. Exposure to lignans, which may yield toxicity, appears to be greater from capsules or tablets than from chaparral tea.

Safety

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Interactions

Interactions with Drugs
Based on animal studies and human case reports, chaparral has been associated with kidney damage, cysts, cancer, and kidney failure. Theoretically, use of chaparral with other agents known to alter kidney function or induce toxicity should be avoided, including sulfa antibiotics, aminoglycoside antibiotics, COX-2 inhibitors, NSAIDs, and a number of other drugs. Patients who are using other medications and who are considering chaparral should consult with a qualified healthcare professional, including a pharmacist. Based on animal study and human case reports, chaparral has also been associated with liver damage. Theoretically, the use of chaparral with other agents known to induce liver toxicity should be avoided; these include amiodarone, carmustine, or danazol.
Based on animal study, chaparral may lower blood sugar levels. Caution is advised when using medications that may also lower blood sugar. Patients taking drugs for diabetes by mouth or injection should be monitored closely by a qualified healthcare professional. Medication adjustments may be necessary. Based on human research, chaparral may increase the risk of bleeding when taken with drugs that also increase the risk of bleeding. Some examples include aspirin, anticoagulants ("blood thinners") such as warfarin (Coumadin?) or heparin, anti-platelet drugs such as clopidogrel (Plavix?), and non-steroidal anti-inflammatory drugs such as ibuprofen (Motrin?, Advil?) or naproxen (Naprosyn?, Aleve?).
Based on animal research, chaparral may interfere with the way the body processes certain drugs using the liver's cytochrome P450 enzyme system. As a result, the levels of these drugs may be increased in the blood and may cause increased effects or potentially serious adverse reactions. Patients using any medications should check the package insert and speak with a qualified healthcare professional or pharmacist about possible interactions. Based on historical use, chaparral may interact with monoamine oxidase inhibitors (MAOIs), such as isocarboxazid (Marplan?), phenelzine (Nardil?), and tranylcypromine (Parnate?). There is also the possibility that blood pressure may become dangerously high if chaparral is taken with MAOIs, although there is limited research supporting this.
Chaparral may aggravate indomethacin-induced gastric ulcers and inhibit the metabolism of barbiturate drugs like phenobarbital. Effects of thyroid medications may be altered although this is unproven.
Chaparral may also interact with cancer, antiviral, gastrointestinal, immunosuppressant, thyroid, and abortion-inducing drugs.

Attribution

This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

Bibliography

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