Dong Quai - Medicinal Uses, Interactions, Side Effects, Dosage

Dong Quai
Dong quai is also known as dang gui, tang-kuei, Chinese Angelica, or "female ginseng," and is a member of the carrot and parsley family. A. sinensis is the most widely used of the Angelica species, although other species are found in traditional medicines of different cultures. The roots and rhizomes are the most extensively used parts of the plant.
Uses and Benefits:
Dong quai is a popular Chinese medicinal herb, frequently used in formulations for gynecologic disorders. In the U.S., it is often marketed as a general female tonic, labeled simply for "female balance and well being"; it is also used specifically to treat premenstrual syndrome, amenorrhea, irregular menses, dysmenorrhea, and menopausal symptoms. In traditional Chinese medicine, dong quai is used for general health promotion, "blood deficiency" conditions, and for many gynecologic and obstetric disorders.
Pharmacology:
Important chemical constituents reported to be in A. sinensis include ligustilide, ferulic acid, polysaccharides, and furanocoumarins (such as psoralen).However, a recent analysis failed to find coumarins in commercial dong quai products.
The biologic activity of A. sinensis extracts has been investi­gated in a wide range of in vitro and animal experiments, primarily in China and Japan. In the 1950s, two different extracts demon­strated opposing uterine muscle activity in animal models.38,9 A volatile oil component of dong quai was found to inhibit sponta­neous uterine contractions in isolated uteri (less marked effect was seen after intravenous administration to whole animals). In contrast, a water- or alcohol-based component administered in­travenously strengthened and increased uterine contractions in vivo. Ferulic acid, a component of A. sinensis, was found to have
 
Numerous other in vitro and animal studies have been published in the Asian literature documenting the pharmacologic acvity of dong quai extracts or isolated chemical components. I ilese include various cardiovascular, hematologic, immuno­, anti-inflammatory, and analgesic effects. However, cause of the widely varying experimental conditions, doses, animal models, it is difficult to extrapolate these effects to Iluman use.
Dong quai is not considered to be estrogenic in the Chinese litature,8 but modern western herbalists often ascribe estrogenic ;Ictivity to this herb. In Chinese pharmacologic studies, no estrojenic effects were seen on vaginal smears of mice, and rodents led dong quai as 5% of their diet did not develop increased uter­ine weights. This lack of hormonal effect is supported by an in vitro U.S. study, in which dong quai did not bind to estrogen receptors (ERs), nor did it stimulate cell proliferation in ER-positive human breast cancer cells. However, contrasting results were found in an unpublished study in which dong quai did bind to es­trogen receptors in vitro, and adding the herb to the feed of ovariectomized rats reportedly increased uterine weight.
Clinical Trials:
A well-designed U.S. clinical trial evaluated dong quai as a single herb for the treatment of menopausal symp­toms. This randomized, double-blind, placebo-controlled trial evaluated postmenopausal women with hot flashes. Subjects were randomized to treatment with a placebo or 4.5 g/day of a standardized dong quai root product (500 mg/capsule; 3 capsules t.i.d.) for 24 weeks. Subjects were evaluated for serum hormone concentrations, vaginal cell maturation, endometrial proliferation with transvaginal ultrasonography, and menopausal symptoms with a self-reported diary of hot flashes and a menopausal index score. There were no statistically significant differences between the dong quai group and the placebo group in any parameter that was tested. Participants were unable to distinguish between herb and placebo, and both groups noted similar incidence of side ef­fects (burping, gas, and headache).
One small, randomized, double-blind, and placebo-controlled U.S. study evaluated a combination of dong quai with four other herbs in 13 women with menopausal symptoms over 3 months The authors reported improvement in menopausal symptoms, but the results were difficult to interpret due to lack of data and the small study size. A Japanese double-blind, placebo-controlled trial found a combination of dong quai with five other herbs to have significant analgesic effects in 40 women with dysmenor­rhea. i8 Hormone levels were not affected. A single U.S. case report of a decoction made from dong quai and peony root was associated with improvement of erythropoietin-resistant anemia secondary to chronic renal failure.
Traditional dong quai-containing formulas, in combination with other herbs, have been reported in the Chinese and herbal litera­ture to be effective for dysmenorrhea, amenorrhea, menopausal symptoms, pelvic infections, premenstrual syndrome, hepatitis, chronic obstructive pulmonary disease, chronic glomerulonephri­tis, and other disorders. Chinese physicians have also admin­istered dong quai by injection (IV, 1M, or into acupuncture sites) to treat conditions such as pain syndromes, thromboangiitis obliter­ans, chronic pelvic infections, Raynaud's disease, rheumatoid arthritis, stroke, and allergic rhinitis. However, most of this literature relies partially or completely on traditional Chinese medi­cine theories of diagnosis and treatment, and these primarily uncontrolled studies and case series are methodologically inade­quate to allow scientific evaluation of efficacy.
Adverse Effects
Dong quai is generally thought to have few, if any, adverse effects. Side effects were not different from placebo in the largest controlled trial. One case report of hypertension accompanied by headache, weakness, and vomiting was associated with ingesting two helpings of a traditional dong quai soup in a 32-year-old woman; her 3-week-old son also had mildly elevated blood pressure while breast feeding. A cause and effect relationship with the dong quai component of the soup is unclear. Herbalists often state that dong quai has mild laxative properties, which is most likely based on ancient Chinese writings that it "lubricates the bowel," but this effect has not otherwise been reported.
Side Effects and Interactions:
Two case reports suggest that dong quai may potentiate the anticoagulant effects of warfarin. A 46-year-old woman therapeutically maintained on warfarin experienced a two-fold elevation of the international normalized ratio (INR) after taking 1-2 tablets daily of dong quai (565 mg/tab; Nature's Way), Wllich resolved over several weeks after discontinuation of the herd. Another patient stabilized on warfarin for 10 years presented with widespread bruising and an INR of 101 month after starting dong quai for menopausal symptoms; details of this case ,are not provided.
Cautions:
Based on animal experiments, Chinese scientists Have been concerned that dong quai may similarly affect the Iiterus and blood coagulation of humans, and thus recommend that it be avoided in early pregnancy, bleeding disorders, and menorrhagia. Because dong quai may contain furanocoumarins (e.g., psoralen), some feel that users should be cautioned about potential photosensitization (occasionally seen in persons collecting plants that contain these chemicals), and even about the potential photocarcinogenic or mutagenic effects of psoralens. However, to put this in the proper perspective, these chemicals are also found in many edible plants, such as parsnip, celery, and parsley. Ingestion of large amounts may increase the risk of phototoxicity in patients undergoing treatment with psoralen ultra­violet A (PUVA); however, a recent analysis failed to find furanocoumarins in dong quai products.
Preparations & Doses:
The daily dose of dong quai prescribed by practitioners of traditional Chinese medicine is usually 4-15 g, administered as the whole root or root slices. Dong quai is traditionally used in combination with many other herbs, often prepared in teas, soups, or other dishes, but commercial products are also available in a variety of powdered root or extract formulations. North American consumers can purchase dong quai as a single or combination herbal preparation that contains about 100-500 mg of root or root extract per dosage form, with a wide variety of recommended dosing regimens.
Summary Evaluation:
Beneficial claims for dong quai are based primarily on theories of traditional Chinese medicine, in vitro and animal studies, and un­controlled clinical trials and case series-all of which suggest beneficial effects but are methodologically inadequate to es­tablish effectiveness. The only well-designed, controlled clinical trial of dong quai used alone did not demonstrate any estrogenic activity or benefits for menopausal symptoms, and thus there is no high-quality evidence to support its use. The use of dong quai in combination with other herbs has been evaluated in few ade­quately controlled, clinical trials. Based on long historical use and limited clinical studies, dong quai appears safe and well tolerated.

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