Angelica sinensis (Oliv.) Diels. (Chinese name Dang Gui) is a member of the family Umbelliferae. There are 80 species of Angelica, mainly distributed in the northern temperate zone and New Zealand. In China, there are approximately 40 species, mainly distributed in the south-west, north-east and north-west zones, e.g. in the provinces of Yung Nan, Si Chuan, Shan Si, Hu Bei, Gan Su etc. The altitude of these areas is about 1500-3000 m, the annual average temperature is 5.5-11.4°C, the annual rainfall is 500-600 mm. A few species of Angelica may be used for food, forage and medicine. The common species are A. acutiloba (Sieb. et Zucc), A. polymorpha, Maxin, A. porphyrocoulis Naxai et Kitag, A. tsinlingensis, A. sinensis etc., of which A. sinensis is the most important. A. sinensis: perennial herb (80-150 cm), leaves tridigitato-pinnate divided, petioles expand tubular sheath, flowers white compound umbel, fruit longelliptic lateral angular with wide wings.
As a cultivated plant, Dang Gui (A. sinensis) is mainly produced in the southeast of the Gan Su province, China, e.g. Min Xian and Dang Chang Xian. Since 1970, Dang Gui has also been produced in Shan Xi, Si Chuan and Yung Nan provinces, the seeds, seedlings and cultivating techniques being still provided from Min Xian, in the Gan Su province. In comparison with other zones of cultivation, the quality, yield and the cultivating acreage of the herb in Min Xian are the best and most extended.
Angelica sinensis (Oliv.): Medicinal Value
Dang Gui is one of the most precious Chinese herbs. As early as 2000 years ago, it was listed among important traditional Chinese medicines. In the Ming Dynasty, Li Shizheng (1578) wrote in his famous medical treatise Compendium of Materia Medica that “Dang Gui, regulating the blood, is the important medicine for women”. Dang Gui root is used medicinally, its medical properties are mild and its taste is bitter and hot. It has the function of enriching the blood, and stimulates its circulation, regulating menstruation and relieving pain etc. It is also widely used in cases of blood deficiency and consequent pathological changes, lumbago, pain in vital organs, constipation, extravasated blood in metal-inflicted wounds, swelling and pain with ulcer, rheumatism and paralysis, amenorrhoea in women, uterine bleeding etc. Owing to its powerful effect, Dang Gui has long been prescribed in “nine out of ten prescriptions”. In traditional Chinese medicine, a most famous prescription, named the Dang Gui Si Wu Tang decoction, consists of the roots of A. sinensis, Paeoniae lactiflorae, Rehmannia glutinosa and Ligusticum wallichii, from which more than ten medicines have been developed. For example, the Hsiao Yao Wan (Bupleurum sedative pills) consisting of radix A. sinensis, Bupleuri paeoniae, Poria, Rhizoma atractylodis macrocepgalae (18.18%) separately plus radix Glycyrrhizae (9.10%), functions to relieve discomfort caused by hepatic dysfunction, abdominal and chest flatulence, and also pain. In addition, the Chinese have consistently held that it is an excellent nourishing tonic, so that Dang Gui is used in stewing chicken and meat. Many dishes supplemented partly with the herb are known in China, among them Dang Gui Wine, Dang Gui-Huangqi-Zao Jin (A. sinensis-Astragalus membranaceus-Jujube Wine) and Dang Gui toffee are traditional productions.
Studies on the pharmacology and clinical use of Dang Gui are becoming more extensive. Chon Yuanpeng et al. reported that after an intravenous injection of Dang Gui at a dosage of 2 g/kg in anaesthetized dogs, coronary, cerebral and peripheral blood flow increased, and arterial blood pressure, vascular resistance, total peripheral resistance and myocardial oxygen consumption decreased. The results of intravenous injection of Dang Gui at a dose of 20 g/kg inhibiting platelet aggregation in rats were reported by Yin Zhongzhu et al.. When sodium ferulate was administered intravenously at doses of 0.1-0.2 g/kg an inhibitory effect on platelet aggregation was also observed. The aqueous extract in the treatment of cerebral thrombosis and thromboangiitis obliterans seems to be related to the inhibition of platelet aggregation and release of 5-HT from platelets. Xu Lina et al. studied this effect and its constituent ferulic acid on phagocytosis in mice. The plasma Gougo red concentration was decreased after an intravenous injection of Dang Gui at a dose of 16 g/kg. A similar effect was observed after intravenous administration of sodium ferulate at dosages of 100-200 mg/kg. The phagocytosis percentage and phagocytosis index were increased when sodium ferulate was given either subcutaneously (0.2 g/kg/day) or orally (0.3 g/kg/day) for 4 days. Dang Gui (20 g/kg subcutaneously) manifested a similar effect. Xu Lina et al. also studied the an-tithrombotic effect of sodium ferulate in rats. The results indicate that sodium ferulate may be of value in the treatment of thrombo-embolic diseases. Cha Li reported the obvious anti-arrhythmic action of Dang Gui on experimental arrhythmias. Xu Cuihua and Wang Jingchuen reported the promoting effects on protein production and RNA, DNA synthesis in cultured liver cell. Tao Jingyi et al. isolated ligustilide from the essential oil of Dang Gui cultivated in Min Xian, Gan Su province. It was shown in a series of experiments to have a remarkable anti-asthmatic effect and spasmolytic action. When injected into guinea pigs intraperitoneally at a dose of 0.14 ml/kg, the asthmatic reaction induced by acetylcholine and histamine was immediately impeded at a potency approximately equal to the action of aminophylline (50mg/kg). A lung overflow experiment showed that an intravenous injection of ligustilide (0.08 ml/kg) into the anaesthetized guinea pig caused complete or partial blockage of the reaction of histamine at the dose of 2-10 μg/kg. Ligustilide also exhibited an anti-spasmodic effect on the isolated trachea strip of the guinea pig contracted by acetylcholine, histamine and barium chloride, and a relaxation effect on trachea strip under normal tension. The contents of cAMP and cGMP in the pulmonary and intestinal tissues of the guinea pig were not altered by treatment with ligustilide. Clinical practice with various chemical ingredients of Dang Gui has been studied.
Conventional Practices for Propagation
As early as 1500 years ago, Dang Gui (A. sinensis) was cultivated in Ming Xian, Dang Chang Xian, Gan Su province in China. The following are the cultivation processes.
L Growing Seedlings. Virgin soil, overgrown with weeds, shady and damp, must be deeply ploughed. Set fire to the weeds when they are dry and the ashes may be used as a basic fertilizer. The soil is raked level and is piled up as a seedling bed (1 m wide), in which the seeds (8 g/m2) are sown within the first 10 days of June. The seedling bed must be covered with fine-grained soil, 3 mm thick, and with weeds, 3 cm thick, for shade and conservation of heat and soil moisture. The shoots emerge in 15-20 days, and the cover may be loosened in 40 days. The seedlings (root d = 0.3-0.5 cm) are dug out from the seedling bed within the first 10 days of October and stored in a room or vegetable cellar during the winter.
2. Transplanting Seedlings. After the soil thaws in the spring of the second year, the seedlings are transplanted into the field, at best 6000-8000 per mu (lmu = 666.66 m2).
3. Field Management. After the shoots emerge, fill the gaps with seedlings. Hoe up weeds and loosen the soil. Prevention and control of plant diseases and elimination of pests must be actively undertaken.
4. Harvest. The leaves, from which the essential oil may be extracted, are cut before the frost season. The medicinal roots can then be dug out after frosting.
5. Selection of Variety. The plants flowered in the summer and seeds were picked in the autumn of the third year.
The problems in production are: (1) The growing seedlings must be set in ploughed virgin soil. In Min Xian, for instance, 10 ha of virgin soil are ploughed in one county alone, so that vegetation and ecological environment have been destroyed. (2) Dang Gui plants are endangered by plant diseases and insect pests. The growth of the herb is restricted by natural conditions.
Conventional Production of the Medicament
The processing of A. sinensis is an important part of its production and marketing. If the process does not meet the specifications, the essential oil in the roots may diffuse and the roots mildew and rot. The fresh roots are tied into 1-kg bunches and fumigated for 1 month. The smoked-dry roots are packed and stored. In processing, the dry roots are steeped first, and then cut into small pieces (2 mm thick) that may be used in decoction according to prescription, or are crushed, sifted, processed into more than ten forms of drug, e.g. as powder, injection, pill, tablet, Dang Gui Su, Fu Ke Yang Ying Wan, Nii Ke Ba Zhen Wan (“women’s precious pills”), various Dang Gui wines etc.
Demand on Chinese and World Markets
Owing to its medicinal value and use in health protection, the demand for A. sinensis has been increasing daily. At present, in the south of Guan Su province alone, the acreage under A. sinensis is about 6000-7000 ha. The total output reaches 13 000 t, which amounted to about 85% -90% of the needs of all China. More than ten pharmaceutical factories, for instance Lanzhou Fo Ci Yao Chang, use Dang Gui as a raw material to produce various medicines and chemical reagents.
A. sinensis has been well received by oriental nations from ancient times to the present. As pharmacological studies and new products have developed, medicines made with it have received increasing attention on both Chinese and world markets. At present the demand has been greatest in Hong Kong, Aomen and East-South Asia, but part of the production has been sold to other countries. The exports of A. sinensis reach 7001. Especially Dang Gui Nong Su Wan (a pill containing enriched extract of Dang Gui) and the Dang Gui Di Wan (a pill containing the essential oil of Dang Gui) which had been studied and produced in recent years, which achieves good results in gynaecological ailments, diarrhoea and thrombosis, have been well received by Chinese and foreign firms.
Angelica sinensis (Oliv.): Conclusions and Prospects
Dang Gui is an important medicinal herb, well received in many countries. With further processing and production of series products, it will be used more widely in medical treatment, health protection, and space flight (as a food ingredient for cosmonauts), and the demand for it will increase in the years to come. Nevertheless, conventional cultivation requires a great cultivation area (6000-7000 ha in Gansu province, China) and the vegetation and ecological environment have inevitably been destroyed during the process of seedling propagation. It requires, moreover, a lot of manpower and fertilizer, and is controlled by natural conditions and by plant diseases and insect pests. Fortunately, the callus, which can produce essential oil (Zhang Shi-yu, unpubl.), grows under artificial conditions in our laboratory and is not restricted by natural factors. It can be predicted that with the development of biotechnology and the unfolding of studies on cell clone and mutant induction, biotechniques will play a more important role in the medicinal production of Angelica sinensis.
Selections from the book: “Medicinal and Aromatic Plants II”, 1989.