Rhizoma Dioscoreae
- Name
- Origin
- Where Does It Grow?
- Nature and Flavor
- Identified Active Components / Major Chemical Constituents
- Drug Actions in TCM
- Traditional Uses in TCM
- Pharmacological Actions
- Toxicology
- Administration and Dosage
- Adverse Effect, Side Effects and Cautions
- References
Name
Latin Name: Rhizoma Dioscoreae
Common Name: Chinese yam
Scientific Name: Dioscorea opposita Thunb.
Chinese Name: 山藥
Pinyin Name: shan yao
Origin
The root of Dioscorea opposita Thunb., a perennial trailing plant of the Dioscoreaceae family. The medicinal part is used in raw form or processed by stir-frying with bran.1,2
Where Does It Grow?
Chinese yam is mainly produced in Henan province; other regions like Hunan, Jiangxi, Guangdong and Guangxi provinces are also produced. All of them provide cultivated herbs.1
Nature and Flavor
Chinese yam is neutral in nature, sweet in flavor, and mainly manifests its therapeutic actions in the spleen, lung and kidney meridians.2
Identified Active Components / Major Chemical Constituents
Active components in Chinese yam include mucopolysaccharides, diosgenin, allantoin, batatasin I, saponins, dopamine, essential amino acids, flavonoids, and amylase.4,5
Drug Actions in TCM
Chinese yam can replenish qi (vital energy), enrich yin, reinforce spleen, lung and kidney, and arrest excessive essence depletion.2Traditional Uses in TCM
Chinese yam is mainly used in spleen and stomach weakness, poor appetite, diarrhea and excessive vaginal discharges. Other conditions such as chronic coughing due to lung weakness; or kidney weakness that leads to nocturnal emission, urinary frequency, excessive thirst or hunger are also indicated.2,3,4
Chinese yam invigorates the spleen to promote qi production
For spleen deficiency conditions such as general weakness, poor appetite, loose bowels and child indigestion, Chinese yam can be used alone, being a tonic or simply adding in diet. Clinically, it is usually combined with herbs like pilose asiabell root, largehead atractylodes rhizome, poria, lotus seed, hyacinth bean and euryale seed in the remedies.
Chinese yam nourishes the lungs and replenishes qi
For deficiency of lung qi that leads to breath shortness, general weakness, and a feeble voice, it is suitable to use Chinese yam along with herbs like pilose asiabell root, astragalus root, largehead atractylodes rhizome, tangerine peel and schisandra for relief. When the individual has coughing with bloody sputum, it can be treated by Chinese yam along with American ginseng, llily bulb, dwarf lily-turf tuber, anemarrhena rhizome, rehmannia root and donkey-hide gelatin. For asthmatic conditions that resulted from kidney and lung deficiencies, Chinese yam can be used with processed rehmannia root, cornus fruit, Asian ginseng and schisandra to reinforce the organs, and consolidate qi and arrest asthmatic symptoms.
Chinese yam aids lung yin and kidney yin
In TCM, the body's physical forms pertain to yin. Chinese yam can be used in diabetes, diabetic insipidus, or hyperthyroidism individuals who present with yin deficiency symptoms. Physicians will prescribe a very high dose when using alone. When the herb combines with astragalus root, anemarrhena rhizome, kudzu root and snakegourd root, the results will be better. In severe cases that have excessive thirsty and frequent urination, gypsum and golden thread rhizome are added to enhance the overall effects.
Chinese yam reinforces the consolidating and grasping actions of kidney
Kidney deficiency causes seminal emission, Chinese yam is used with processed rehmannia root, cornus fruit, euryale seed and lotus seed; kidney yang deficiency causes urinary frequency or incontinence, Chinese yam can be used with spicebush root and sharpleaf glangal fruit.
Chinese yam invigorates spleen and kidney
This is beneficial to excessive vaginal discharge in women, in which Chinese yam is used with largehead atractylodes rhizome, poria and euryale seed. When the vaginal discharge is yellowish, thick and foul smelling, then amur corktree bark and sopora root are added in to expel the damp and heat pathogens in the lower burner. In TCM, the vagina belongs to part of the genitalia and is mainly supported by the spleen and kidney.
Since the curative effects of Chinese yaw is gentle, it usually acts as an associate ingredient, cannot exerts the major and leading effects in a formula. However, this makes it a popular dietary ingredient or tonic among the general public.
Pharmacological Actions
Researches have showed that Chinese yam can affect the sugar metabolism, regulate immune functions, anti-aging, and promote the digestive functions of stomach and intestines.5
Toxicology
None.4
Administration and Dosage
Orally, the usual dose is 15～30g, it can be up to 60～250g if necessary. Chinese yam in raw form is suggested for nourishing yin, when stir-fried with bran, it can invigorate spleen and arrest diarrhea.2
Adverse Effect, Side Effects and Cautions
None.4
References
- Li Jiashi (editor-in-chief), Chinese Medicine Identification, Shanghai Scientific and Technical Publishers, 2000-2.
- Lui Daiquan (editor-in-chief), Chinese Herbal Medicine, Shanghai Scientific and Technical Publishers, 2000-6.
- Tao Yufeng, Clinical Herbal Medicine, People¡¦s Medical Publishing House, 2005-5.
- Chen Pian, Clinical Application of Tonifying Herbs, Second Military Medical University Press, 2008..
- http://www.tcmlib.com/zy/html23/showdetail-323237322ce5b1b1e88daf2c7a79.html
