Taxonomic class

Apiaceae

Common Trade Names

Dong Kwai, Dong Quai Capsules, Dong Quai Fluid Extract

Common Forms

Raw root: 4.5 to 30 g (boil or soak in wine)

Tablet (fluidextract): 0.5 g

Also available as capsules, powders, teas and, in some countries, injectable forms.

Source

Active components are obtained from the roots of dong quai (Angelica polymorpha var. sinensis), a fragrant perennial umbelliferous herb that is native to China, Korea, and Japan.

Chemical Components

The volatile oils extracted from the root contain n-butylphthalide, cadinene, carvacrol, dihydrophthalmic anhydride, folinic acid, isosafrole, ligustilide, nicotinic acid, safrole, succinic acid, uracil, and vitamin B12. Coumarin derivatives identified in dong quai include bergapten, imperatorin, osthole, oxypeucedanin, and psoralen. Ferulic acid has also been found.

Actions

Dong quai alters uterine activity in female rabbits. The volatile oil has an inhibitory action on the uterus, whereas the nonvolatile and water-and alcohol-soluble components have stimulatory action.

Studies conducted in rats showed increases in metabolism, oxygen use by the liver, and glutamic acid and cysteine oxidation; these actions may be attributed to vitamin B12 and folinic acid that occur in the herb’s root.

Dong quai extracts, especially alcoholic extracts, were also found to exert quinidine-type effects, prolong the refractory period, and correct atrial fibrillation in animals. Other studies in rats showed that these extracts may prevent atherosclerosis, expand coronary arteries, and increase coronary blood flow. Some coumarins are known to act as vasodilators. Although studies in animals have shown that the volatile oil exerts vasodilatory action to lower blood pressure, the duration of action is short.

Reported Uses

Dong quai is recommended by Western herbalists for many gynecologic disorders, including dysmenorrhea, excessive fetal movement, menstrual irregularities, chronic pelvic infection, and premenstrual syndrome. Most claims are based on data from animal studies or small, uncontrolled human trials, but in a double-blind, placebo-controlled trial of 71 postmenopausal women, dong quai alone was found not to produce estrogen-like responses in endometrial thickness or vaginal maturation and not to be useful in managing postmenopausal symptoms . In traditional Chinese medicine, dong quai is used in combination with other herbs to relieve dysmenorrhea and other disorders. Kotani and colleagues evaluated such an herbal preparation including dong quai in 41 women with dysmenorrhea and found it effective in diminishing symptoms. Because an NSAID was allowed on an as- needed basis, it is difficult to determine the effect of the herbal preparation. Other reported uses include treatment of Buerger’s disease, constipation, headache, hepatitis, hepatocirrhosis, herpes zoster, hypertension, malaria, neuralgia, pyogenic infection, Raynaud’s disease, chronic rhinitis, sepsis, toothache, and ulcerous diseases or abscess. None of these uses has been evaluated clinically.

Dosage

Dosage forms, strengths, and extraction forms vary. In a placebo­controlled study evaluating the estrogenic effects of dong quai on endometrial thickness in postmenopausal women, 500-mg capsules taken P.O. t.i.d. (equivalent to 0.5 mg/kg of ferulic acid), for a total daily dose 4.5 g of root, were used.

Adverse Reactions

GI: diarrhea.

Hematologic: bleeding.

Skin: increased photosensitivity (psoralens in herb may cause severe photodermatitis) .

Other: fever.

Interactions

Anticoagulants, antiplatelets: May enhance effects. Avoid administration with dong quai.

Contraindications And Precautions

Safrole, a component of the volatile oil, is carcinogenic and not recommended for ingestion. Dong quai is contraindicated in pregnant or breast-feeding patients because its chemical components may cause fetal harm. Traditional Chinese texts advise against using dong quai in the presence of an acute infection.

Special Considerations

Monitor the patient for potential bleeding.

Ask why the patient is using dong quai and suggest that he seek a health care provider to address these concerns.

Caution the patient that some of the herb’s components have been shown to increase the risk of some cancers.

Instruct the patient who becomes photosensitive to use sunblock and to wear adequate clothing and sunglasses.

Caution the patient against using dong quai for its yet unproven estrogenic effects.

Advise women to report planned or suspected pregnancy and to avoid using this herb during pregnancy or when breast-feeding.

Commentary

Despite numerous therapeutic claims for dong quai, only a few controlled clinical trials and animal-based studies are available to support its use to treat dysmenorrhea. Most claims regarding dong quai are unsubstantiated and need additional investigation. Dong quai appears to have more than 18 active chemical components, many of which exert widely divergent pharmacologic effects. Some components are carcinogens, and adverse effects of others are unknown. Extensive testing of individual components is needed before dong quai can be regarded as safe or effective.