Rehmannia is the root of the Rehmannia glutinosa, or closely related species. It's an important traditional Chinese herbal medicine. In this medical system its uses vary depending on whether the root has been cured or not. Curing rehmannia involves washing the fresh roots in millet wine before steaming and drying several times. It is used to treat hot conditions, which translate well into western herbal medical uses as well.
Rehmannia is used to reduce fevers, rashes, inflammation, infections, and rheumatoid arthritis which can all be described in Chinese medicine as "hot" conditions. Additionally rehmannia is used to treat diabetes, adrenal fatigue, heart conditions, hemmorhaging, and insomnia.
The best use of this plant is in combination with other herbs. It's a great alternative for fatigue if licorice is contraindicated.
- Adrenal tonic
- Mild laxative
10-30 g/dried root/day
Liquid Extract (1:2)
*Unless stated otherwise, rehmannia is generally used in the uncured form.*
Long term use is appropriate .
Rehmannia is generally used at fairly high doses. **
- Weak adrenal function
- To prevent the suppressive effects of corticosteroid drugs on endogenous corticosteroid levels.
- Adrenal insufficiency
- Chronic nephritis
Di Huang (China) (Cured)
- Shu Di Huang (Cured)
- Shen Di Huang (Uncured)
+ Western Herbal Medicine
Still compiling research.
+ Traditional Chinese Medicine
In traditional Chinese medicine, cured rehmannia and uncured rehmannia is used differently. Uncured rehmannia is used to reduce fevers and heat conditions, as a haemostatic, to remove heat from the blood, for rashes, diabetes, low grade fevers and for bleeding. . Cured rehmannia on the other hand, was used to regulate mentruation, promote blood production, correct anaeima dizziness, weakness, tinnitus, amenorrhea, and mettorhagia .
Added to formulas to tonify yin in the liver, kidney and heart, and add a cooling, anti-inflammatory actions. [4, 6].
Prepared rehmannia is a fundamental kidney tonic in Chinese herbalism and is often associated with longevity. It is a yin jing tonic, and frequently added to formulas designed to strengthen sexual function. .
Rehmannia is a perennial herb growing up to 40 cm in height. The flowers are reddish-purple and tubular in shape. The root is a thick orange tuberous root. .
Habitat Ecology, and Distribution:
Still compiling research
Harvesting Collection, and Preparation:
Curing rehmannia (prepared rehmannia) involves washing the fresh root in millet wine, before steaming, and drying several times each. . In Chinese medicine, the prepared version is more highly regarded than fresh rehmannia.
Rehmannia contains around 31 different iridoid glycosides (including aucubin, catalpol, ajugol, rehmanniosides A-D, jioglutosides, and rehmaglutins A-D), as well as other glycosides such as phenethyl alcohol glycosides (jionosides) ionine glycosides, and terpenoid glycosides, as well as polysaccharides, [1-4, 7-10].
Pharmacology and Medical Research:
+ Adrenal Tonic
Not hypertensive like licorice but is toning to the adrenals and may be useful for preventing the suppressive effects corticosteroid drugs. .
It appears to antagonize the suppressive effect of glucocorticoids on the hypothalamic-pituitary-adrenal axis (uncured) [CITATION NEEDED].
Catalpol from rehmannia was shown to increase hydrocortisone levels, and decrease CRH and ACTH in rats with Azheimer's disease after 7 days . This suggests modulating activity on the HPA axis in neuroendocrine dysregulated organisms.
+ Alzheimer's Disease
Alzheimer's disease is believed to have a number of causes and contributing factors. One of them being a dysfunction of neuroendocrine function .This is due to an increase in glucocorticoids in the blood, resulting in a reduction in corticotropin releasing hormone (CRH), and neuronal loss in the hippocampus. This ultimatly leads to reduced memory and cognitive capacity, promoting the progression of Alzheimer's disease .
Studies on mice comparing the effects of catalpol purified from rehmannia and the common anti-Alzheimer's drug donepezil found that catalpol was as effective for reducing biological markers for Alzheimer's disease at a dose of 14mg/day as donepezil at 1.4mg/day. This mechanism of action was noted to be through mechanisms unrelated to antiacetylcholinesterase activity. . The researchers in this study noted a decrease in
Another animal study investigated the role rehmannias main active constituent, catalpol, on HPA axis function in an Alzheimer's disease rat model. Researchers in this study reported a reduction in elevated hydrocortisone level as well as decreased CRH & ACTH. Structural changes associated with AD were also noted, including an increase in CRHR1 positive neurons. .
+ Adaptogenic Effects
The majority of studies on the interaction of rehmannia on glucocorticoids, HPA/HPG interaction, and adrenal function are in vitro, or animal research only. There are no randomised clinical trials available at the time of writing.
In vivo research has suggested HPA axis regulation as a mechanism of action for rehmannias effectiveness on Alzheimer’s disease . This is based on earlier research that linked high cortisol levels with Alzheimer’s disease through a gradual dysregulation of CRH sensitivity in the hippocampus . Other animal studies supported with results involving changes in key HPA axis hormones in a neuroendocrine dysregulated rat model of Alzheimer’s disease after treatment of an rehmannia extract (catalpol) . Researchers in this study reported a reduction in elevated hydrocortisone (cortisol) levels as well as decreased CRH & ACTH. Structural changes associated with AD were also noted, including an increase in CRHR1 positive neurons. These findings suggest directly modulating activity of rehmannia constituents on the HPA axis.
Other animal studies suggesting HPA or HPG axis modulation in conditions traditionally classified as “yin deficiency” includes diabetes, immunosuppression , and bone catabolism .
Online sources have suggested an inhibition of cortisone metabolism in the liver as a mechanism of action, however, no peer reviewed research has been found to back up this claim.
Combines well with Astragalus for chronic nephritis.
The Sunlight Experiment
Updated: April 2018
Recent Blog Posts:
- Bone K, Mills S. (2013). Principles and Practice of Phytotherapy. Elsevier health. China. (Pg. 799-803).
- Liu, Y. F., Liang, D., Luo, H., Hao, Z. Y., Wang, Y., Zhang, C. L., ... & Yu, D. Q. (2012). Hepatoprotective iridoid glycosides from the roots of Rehmannia glutinosa. Journal of natural products, 75(9), 1625-1631.
- Liu, Y. F., Liang, D., Luo, H., Hao, Z. Y., Wang, Y., Zhang, C. L., ... & Yu, D. Q. (2014). Ionone glycosides from the roots of Rehmannia glutinosa. Journal of Asian natural products research, 16(1), 11-19.
- Fu, G. M., Shi, S. P., Ip, F. C., Pang, H. H., & Ip, N. Y. (2011). A new carotenoid glycoside from Rehmannia glutinosa. Natural product research, 25(13), 1213-1218.
- Bone, K. (2003). A clinical guide to blending liquid herbs: Herbal formulations for the individual patient. Edinburgh [u.a., MO: Churchill Livingstone.
- Teeguarden, R. (2000). The ancient wisdom of the Chinese tonic herbs. New York, NY: Warner Books. (Pg. 179-180).
- Morota, T., Nishimura, H., Sasaki, H., Chin, M., Sugama, K., Katsuhara, T., & Mitsuhashi, H. (1989). Five cyclopentanoid monoterpenes from Rehmannia glutinosa. Phytochemistry, 28(9), 2385-2391.
- Yoshikawa, M., Fukuda, Y., Taniyama, T., Cha, B. C., & Kitagawa, I. (1986). Absolute configurations of rehmaionosides A, B, and C and rehmapicroside three new ionone glucosides and a new monoterpene glucoside from Rehmanniae radix. Chemical and pharmaceutical bulletin, 34(5), 2294-2297.
- Sasaki, H., Nishimura, H., Chin, M., & Mitsuhashi, H. (1989). Hydroxycinnamic acid esters of phenethylalcohol glycosides from Rehmannia glutinosa var. purpurea. Phytochemistry, 28(3), 875-879.
- Morota, T., Sasaki, H., Nishamura, H., Sugama, K., Masao, C.C.Z., & Mitsuhashi, H. (1989). Chemical and biological studies on Rehmanniae radix. Part 4. Two iridoid glycosides from Rehmannia glutinosa. Phytochemistry, 28, 2149–2153
- Kim, H., Lee, E., Lee, S., Shin, T., Kim, Y., & Kim, J. (1998). Effect of Rehmannia glutinosa on immediate type allergic reaction. International journal of immunopharmacology, 20(4-5), 231-240.
- Csernansky, J. G., Dong, H., Fagan, A. M., Wang, L., Xiong, C., Holtzman, D. M., & Morris, J. C. (2006). Plasma cortisol and progression of dementia in subjects with Alzheimer-type dementia. American Journal of Psychiatry, 163(12), 2164-2169.
- Umegaki, H., Ikari, H., Nakahata, H., Endo, H., Suzuki, Y., Ogawa, O., ... & Iguchi, A. (2000). Plasma cortisol levels in elderly female subjects with Alzheimer’s disease: a cross-sectional and longitudinal study. Brain research, 881(2), 241-243.
- Xia, Z., Zhang, R., Wu, P., Xia, Z., & Hu, Y. (2012). Memory defect induced by beta-amyloid plus glutamate receptor agonist is alleviated by catalpol and donepezil through different mechanisms. Brain research, 1441, 27-37.
- Huang, W. J., Niu, H. S., Lin, M. H., Cheng, J. T., & Hsu, F. L. (2010). Antihyperglycemic effect of catalpol in streptozotocin-induced diabetic rats. Journal of natural products, 73(6), 1170-1172.
- Wang, J. H., Li, W. T., Yu, S. T., Xie, H., & Han, H. R. (2014). Catalpol regulates function of hypothalamic-pituitary-adrenocortical-axis in an Alzheimer's disease rat model. Die Pharmazie-An International Journal of Pharmaceutical Sciences, 69(9), 688-693.