Radix Rehmanniae Praeparatae
- 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: Radix Rehmanniae Praeparatae
Common Name: Processed rehmannia root
Scientific Name: Rehmannia glutinosa Libosch.
Chinese Name: 熟地黃 / 熟地
Pinyin Name: shu di huang / shu di
Origin
The root tuber of Rehmannia glutinosa Libosch., of the Scrophulariaceae family. After dried, the herb is processed by mixed with millet wine and then steamed.1,6
Where Does It Grow?
Rehmannia root is widely distributed throughout China. Nowadays, it is mainly cultivated in Henan and Zhejiang provinces, other districts such as Hebei, Shensi, Gansu, Hunan, Hubei, Sichuan, and Shanxi are also produced. The production of Henan is regarded as the genuine one.1,6
Nature and Flavor
Processed rehmannia root is mild warm in nature, sweet in flavor, and mainly manifests its therapeutic actions in the liver and kidney meridians.2
Identified Active Components / Major Chemical Constituents
Processed rehmannia root has similar components as its raw form, which is mainly sterol, glycosides and polysaccharides. But its amount of iridoids, iridoid glycosides and water soluble amino acids are reduced largely, and the monosaccharides are also reduced too. On the other hand, its amount of 5-hydroxymethyl furfural has increased 20 times in comparison with dried rehmannia root.4
In the Pharmacopoeia of People's Republic of China (2010 Edition) - Part I, the level of acteoside should not less than 0.020%, as the standard quality of processed rehmannia root.
Drug Actions in TCM
Processed rehmannia root nourishes yin, replenishes blood, and aids essence and marrow productions.2Traditional Uses in TCM
Porcessed rehmannia root is often used in conditions like lumbar and knee weakness, hot flush, bone pain, night sweats, seminal emission, diabetic symptoms, sallow complex, palpitations, irregular menses, excessive menses, dizziness, ear ringing, and premature graying.2,3
Processed rehmannia root is a commonly used blood tonic
For anemia or blood deficient conditions, processed rehmannia root can work with angelica root, white peony root, and Sichuan lovage rhizome (the Four Substances Decoction) to promote blood production. When the patients also have qi (vital energy) deficiency that accompanies with mental fatigue and general weakness, ginseng should be added to the remedy. Otherwise, the Four Substances Decoction will combine with pilose asiabell root, largehead atractylodes rhizome, poria and liquorice root to formulate as the Eight Treasures Decoction for replenishing both blood and qi. In case of serious anemia or blood deficiency, the remedy may also be added fleeceflower root, donkey-hide gelatin, and suberect spatholobus stem.
Porcessed rehmannia root is commonly used for women health problems
Blood deficiency leads to scanty menses or irregular periods, processed rehmannia root can work with angelica root, white peony root, Sichuan lovage rhizome, bupleurum root and nutgrass flatsedge rhizome for relief. Long term heavy menses flow will lead to blood and yin deficiencies, which can be treated with the herb along with dried rehmannia root, angelica root, white peony root, donkey-hide gelatin, and tortoise shell glue. Processed rehmannia root along with angelica root, himalayan teasel root, mulberry mistletoes, largehead atractylodes rhizome and baical skullcap root can relieve stirring fetus in pregnant women. Blood deficiency or blood stasis in postnatal women will develop abdominal pain, which can be treated by processed rehmannia root along with angelica root, Sichuan lovage rhizome, and cassia bark.
Processed rehmannia root is an important ingredient for yin nourishment
Weakness due to yin deficiency often accompanied with hot flush, night sweats, lumbar soreness, seminal emission, throat dryness, thirst, a red tongue tip and the pulse is rapid and thready. Processed rehmannia root is often used along with cornus fruit, Chinese yam, poria, peony root bark, and oriental water-plantain rhizome to formulate as the Six-ingredient Rehmannia Decoction for relief. In case if the virtual fire symptoms are serious, anemarrhena rhizome, amur corktree bark and tortoise shell will be added to clear the fire. Clinically, modern TCM discovered that conditions like hypertension, diabetes, chronic nephritis, and nervous breakdown tend to have the above situations, and thus the Six-ingredient Rehmannia Decoction is often selected and modified for appropriate conditions.
Processed rehmannia root replenishes kidney essence and recovers marrow storage
Growth retardation in children, or early degeneration and gray hair in middle-aged people are associated with insufficiency of essence and marrow, processed rehmannia root can work with fleeceflower root, glossy privet fruit, wolfberry fruit and tortoise shell glue for improvement. For asthmatic symptoms that associated with kidney deficiency, processed rehmannia root can be selected along with achyranthes root, angelica root, cassia bark and roasted liquorice root. In case of urinary frequency or incontinence, the herb can work with dodder seed, cherokee rose fruit, and palmleaf raspberry fruit to invigorate kidney system and enhance bladder functioning. Chronic diarrhea is often associated with weakness of spleen and kidney, which can be treated by processed rehmannia root along with largehead atractylodes rhizome, Chinese yam and psoralea. A productive cough can be due to kidney weakness that causes excessive dampness and phlegm accumulated inside the body. Processed rehmannia root together with angelica root, pinellia tuber and tangerine peel are selected to dissolve the pathogens and invigorate organ functioning.
Processed rehmannia root nourishes blood, warms up meridians, expels coldness and unblocks stagnations
Processed rehmannia root along with deerhorn glue, cassia bark and ephedra can treat serious infections or chronic inflammations. Modern TCM like to apply the herbal combination to treat conditions like chronic abscesses deep inside the body, Buerger disease, tuberculosis conditions and chronic osteomyelitis.
Pharmacological Actions
Studies showed that processed rehmannia root has effects in immune regulation, promoting adrenal cortex and sex glands functioning, stimulating bone marrow, enhancing blood coagulation process, improving kidney and heart functioning, diuresis, lowering blood pressure, inhibiting gastric secretions, anti-tumor, inhibiting epithelial cell proliferation, anti-oxidative and anti-aging.4,5
Toxicology
See rehmannia root.
Administration and Dosage
For decoction, the usual dose of processed rehmannia root is 9～15g, it can be up to 30g if necessary. The herb is also consumed in syrup, medicinal wine, powder and pill forms. Since processed rehmannia root tend to disturb the digestion and absorption processes, when taking in high dose or for long-term consumption, it is advised to use along with digestant herbs such as villous amomum fruit, so as to prevent the development of stomach upset, abdominal distention, and poor appetite.2,3,4
Adverse Effect, Side Effects and Cautions
Those with poor appetite, loose bowels, thick and greasy tongue coating should use processed rehmannia root with caution.3,4
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, 2008-8.
- http://www.zysj.com.cn/zhongyaocai/yaocai_s/shudihuang.html
- Nanjing University of Chinese Medicine edited, Materia Medica, Shanghai Scientific and Technical Publishers, 2005-5.
