Dong quai: Background. Actions

2010

Historical Note

Dong quai is an aromatic herb commonly used in TCM. Its reputation is second to that of ginseng and is regarded as a ‘female’ remedy, or women’s ginseng. Used in combination with other herbs, dong quai is used to treat numerous menstrual disorders and menopausal symptoms, as well as abdominal pain, migraine headache, rheumatism and anaemia. Dong quai (Angelica sinensis) is closely related to the European Angelica archangelica, a common garden herb and the flavouring in Benedictine and Chartreuse liqueurs.

Common Name

Dong quai

Other Names

Chinese angelica, dang gui, women’s ginseng, tang kuei

Botanical Name / Family

Angelica sinensis (synonym: Angelica polymorpha sinensis) (family Apiaceae [Umbelliferae] — carrot family)

Plant Part Used

Root

Chemical Components

Dong quai contains essential oil (0.4-0.7%) consisting of 45% ligustilide, n-butylphthalide, cadinene, carvacrol, safrole and isosafrol. The root also contains sucrose (40%) and various lactonesand vitamins, together with phytosterols, ferulic acid and coumarins, including osthole, psoralen and bergapten. Ferulic acid and ligustilide are considered to be the main active components and it has been suggested that assessment of total ferulic acid content provides a good measure of herbal quality.

Main Actions

Nearly all studies investigating the pharmacological effects of dong quai have been conducted in vitro or in animals, so it is difficult to predict whether the observed effects are clinically significant.

HORMONE MODULATION AND UTERINE EFFECTS

Studies on the uterine effects of dong quai have produced variable results. A uterine relaxant effect has been attributed to the volatile oil, whereas a uterine stimulant effect has been attributed to an aqueous extract. Animal experiments report that dong quai produces increased uterine excitability, with initial irregular, fast contractions, later slowing and becoming more regular.

Studies of dong quai’s oestrogenic activity have also produced contradictory results. In vitro reports suggest that dong quai has weak oestrogen-receptor-binding activity, producing up-regulation of progesterone-receptor mRNA, and stimulating oestrogen-dependent breast cancer cells independent of oestrogenic activity. An aqueous extract of dong quai was found to stimulate the growth of both oestrogen-receptor-positive and -negative breast cancer cells in vitro, suggesting both a weak oestrogen-agonistic activity and activity independent of oestrogen-receptor-mediated pathways. This is contrasted by a study using several different in vitro bioassays that found that dong quai did not have oestrogenic activity, oestrogen-receptor-binding activity or stimulate the growth of oestrogen-positive breast cancer cells and that it had neutral progestin activity. Dong quai has also been reported to have anti-oestrogenic activity and anti-androgenic activity in vitro.

IMMUNOSTIMULANT EFFECT

It is reported that dong quai can counter the immunosuppressive effects of hydrocortisone in vivo. Immunostimulation is further suggested by in vitro studies demonstrating enhanced cell mediated immunity and upregulation of IL-2 and IFN-gamma, as well as nonspecific lymphoproliferation. A polysaccharide from dong quai has also been found to enhance non-specific immunity while suppressing humoral immunity.

HEPATOPROTECTION

Dong quai is said to improve abnormal protein metabolism in people with chronic hepatitis or hepatic cirrhosis. Evidence comes from an in vivo study in which 5% dong quai was added to the daily diet of rats, resulting in enhanced metabolism, increased hepatic oxygen utilisation, and increased glutamic acid and cysteine oxidation. Dong quai has been found to have antioxidant activity, as well as antiproliferative and pro-apoptotic activities in hepatic stellate cells in vitro, suggesting a potential antifibrotic action.

CARDIAC PROTECTION

Dong quai is reported to have a quinidine-like action, prolonging the cardiac refractory period and correcting atrial fibrillation. An in vitro study of dong quai in conjunction with Astragalus membranaceus demonstrated protection against myocardial ischaemia-reperfusion injury, while in vivo studies report prevention of atherosclerosis, dilation of coronary vessels and increased coronary blood flow. A combined extract of dong quai and Ligusticum chuanxiong has been found to inhibit vascular smooth muscle cell proliferation in vitro.

ANTICOAGULANT AND ANTIPLATELET EFFECTS

Dong quai has been shown to have potent anticoagulant effects, as well as haemostatic effect related to promoting platelet aggregation. In a controlled trial an IV preparation of dong quai was found to prolong prothrombin times significantly more than IV dextran in a group of 96 patients admitted with ischaemic stroke. Dong quai has also been shown to significantly inhibit platelet activation, relieve vascular endothelial cell injury, and improve microcirculation in patients with ulcerative colitis. Ferulicacid, found in dong quai, has been reported to inhibit the aggregation of platelets in blood and retard platelet release of serotonin and adenosine diphosphate. Angelica sinensis has a lower coumarin content than other Angelica species.

ANTICARCINOGENIC

Polysaccharides from dong quai have been shown to possess antitumour effects in experimental in vivo tumour models and inhibitory effects on invasion and metastasis of in vitro hepatocellular carcinoma cells. An acetone extract of dong quai was found to inhibit proliferation of human cancer cells in vitro via induction of cell cycle arrest and apoptosis. There is evidence to suggest that a chloroform extract of dong quai suppresses growth of malignant brain tumour cells in vitro, as well as suppressing growths of malignant brain tumours of rat and human origin and shrinking the volumes of in situ glioblastoma multiforme, significantly prolonging survivals in vivo.

NEUROPROTECTION

Dong quai has been found to be effective in treating acute cerebral infarction. In a case series of 1404 patients with acute cerebral infarction, of whom 692 were treated with dong quai injection, 390 with compound salvia and 322 with low-molecular dextran injection, the group treated with dong quai were found to have significantly better neurological function and a larger reduction of infarcted area than the other groups.

Bak Foong Pills, a combination Chinese herbal formula that contains dong quai and other herbs such as Panax ginseng and Glycyrrhiza uralensis, have been found to have a neuroprotective action, suggesting these herbs may have a use in the treatment of neurodegenerative diseases, such as Parkinson’s disease. A multi-herbal formula (Guibi-tang) containing dong quai has also been shown to improve learning and memory, and to increase the proliferation of hippocampal cells in rats. An aqueous extract of three herbs, including dong quai, has been found to have a neuroprotective action and improve cognitive function in an animal model of vascular dementia and a multi-herbal combination (Danggui-Shaoyao-san) has been found to improve memory and modulate monoamine neurotransmitter metabolism suggesting a possible use for treating senile dementia and Alzheimer’s disease.

GASTROPROTECTION

Polysaccharides derived from dong quai have been found to have a protective effect on colon injury in acetic acid-induced rat colitis, through promotion of growth factors, decreasing oxygen free radicals and some anti-inflammatory effects, as well as relieving the inflammation reaction and colon injury in immunological colitis in rats. A polysaccharide containing extract of dong quai was also shown to promote migration and proliferation of normal gastric epithelial cells and enhance gastric ulcer healing in animal models.

Other Actions

A preparation containing polysaccharides extracted from dong quai has been shown to have a radioprotective effect in mice, as well as an analgesic action in rats.

An in vivo study has shown that dong quai in conjunction with astragalus reduced the deterioration of renal function and histologic damage in an animal model of nephrotic syndrome. Dong quai has also been found to alleviate bleomycin-induded pulmonary fibrosis in rats.

Dong quai promotes melanocytic proliferation, melanin synthesis and tyrosinase activity, suggesting a use in the treatment of skin pigmentation.

An aqueous extract of dong quai has also been found to directly stimulate the proliferation and activity of human osteoprecursor cells in a dose-dependent manner in vitro.

The essential oil of dong quai has been found to have an anxiolytic action similar to diazepam in a mouse model of anxiety.

Various other in vitro and in vivo studies provide some evidence for antispasmodic, anti-allergic and anti-anaemic effects.