Chinese Foxglove
Scientific Name(s): Rehmannia glutinosa (Gaertn.) Libosch. ex Fisch & C.A. Mey
Common Name(s): Chinese foxglove, Di-Huang, Gun-Ji-Whang, Juku-Jio, Jyuku-Jio, Kan-Jiou, Saeng-Ji-Whang, Sheng Di Huang, Sho-Jio, Shou-Jiou, Shoudihuang, Shu Di Huang, Sook-Ji-Whang, To-Byun, Xiandihuang
Medically reviewed by Drugs.com. Last updated on Feb 19, 2025.
Clinical Overview
Use
Rehmannia rhizome extracts have been used extensively in traditional Chinese medicine. Because the preparation is often used in combination with other agents, it is difficult to attribute any benefits to R. glutinosa. Efficacy of R. glutinosa acteoside in the management of primary chronic glomerulonephritis has been suggested; however, clinical trials are lacking to support any use.
Dosing
Clinical studies are lacking to inform dosage. Common nonprescription polyherbal products contain varying amounts of Rehmannia root extract.
Contraindications
Chronic liver disease and GI disorders, including diarrhea.
Pregnancy/Lactation
Avoid use. Rehmannia has traditionally been used as an emmenagogue.
Interactions
None well documented.
Adverse Reactions
Minor and transient adverse reactions have been reported and include GI reactions (eg, diarrhea, abdominal pain), edema, heart palpitations, fatigue, and vertigo.
Toxicology
No data.
Scientific Family
- Scrophulariaceae
Botany
R. glutinosa is a perennial herb that grows wild in northern and northeastern China, particularly in Hunan province. It grows to a height of 0.3 to 0.6 m and has large, sticky leaves and purple flowers. The seed is sown in the autumn and spring; the yellow-brown to blackish-brown root is harvested after the plant has flowered in autumn. The fresh and dried roots and rhizomes have a soft texture, with deep longitudinal wrinkles on the external surface and a darker central cortex.Chevalier 1996, WHO 2007
History
R. glutinosa has been considered a panacea in traditional Chinese medicine, primarily in combination with other herbs. Dried Rehmannia rhizome is reputed to "nourish the yin" and remove heat from the blood, and is used as a tonic for the liver.
Documented historical uses include treatment of anemia, cancer, constipation, diabetes, fatigue, bacterial and fungal infections, hypertension, insomnia, tinnitus, inflammatory conditions, burns, impotence, and osteoporosis.WHO 2007, Zhang 2008
Chemistry
The major chemical constituents of the herb are polysaccharides and iridoid monoterpenes (eg, catalpol, ajugol, aucubin, rehmanniosides, monomelittoside, melittoside, verbascoside, jionosides). Two acidic polysaccharides, rehmannans SA and SB, were isolated from the dried root of R. glutinosa of Chinese origin. These polysaccharides were composed of differing molar ratios of L-arabinose, D-galactose, L-rhamnose, and D-galacturonic acid. Additional polysaccharides have been isolated. Pharmacological activity of the plant species varies depending on processing (dried or steamed) and location of cultivation (eg, Japan vs China). Other sesquiterpenoids and furans have been isolated.Kitagawa 1991, Li 2005, Oshima 1993, Oshio 1982, Tomoda 1994, WHO 2007 The most recently identified constituents include 3 alkaloids, rehmanalkaloids A, B, and C.Li 2017
Uses and Pharmacology
Rehmannia is most commonly used in combination with other herbs. Existing clinical trials do not provide evidence for a definitive place in therapy.
Antiobesity effects
Clinical data
In a small clinical study (N=12), steamed roots of R. glutinosa consumed over 8 weeks decreased waist circumference. The researchers suggested a prebiotic action, based on observed changes in fecal microbiota.Han 2015
Antioxidant effects
In vitro data
Antioxidant effects have been described in several experiments, including in auditory cells.Yu 2006, Yu 2006
Cancer
Animal and in vitro data
One study suggests R. glutinosa steamed root may play a role in regulating apoptosis induced by ultraviolet radiation, presumably through scavenging of reactive oxygen species.Shin 2008 In another study, hot water–extracted R. glutinosa inhibited proliferation and stimulated p53-mediated apoptosis in human hepatocellular carcinoma cells.Chao 2006 Antitumor effects and increases in T-lymphocyte production in mice bearing S180 have also been described for R. glutinosa polysaccharides.Chen 1995, Zhang 2008
Cardiovascular effects
Animal and in vitro data
A 50% ethanolic extract of R. glutinosa inhibited decreases in fibrinolytic activity and erythrocyte deformability, decreases in erythrocyte counts, and increases in connective tissue in rodents. The extract was ineffective in reducing edema and acute or chronic inflammation. R. glutinosa prevented decreases in erythrocyte deformability in rats with endotoxin-induced disseminated intravascular coagulation. In normal rats, R. glutinosa enhanced or increased erythrocyte deformability and fibrinolytic activity. Effects on the hemopoietic system have also been described based on in vitro studies.Kubo 1994, Kubo 1996, Zhang 2008
Clinical data
A small clinical study (N=40) reported on the effect of R. glutinosa pharmacopuncture on heart rate variability, with suggested activation of both the sympathetic and parasympathetic nervous systems.Kim 2016
CNS effects
Animal and in vitro data
In vitro studies and animal models to evaluate the effects of the monoterpene catalpol on aging have been conducted by a limited pool of researchers.WHO 2007, Zhang 2008 Catalpol exerted antioxidant effects on glial cell cultures, protected against beta-amyloid–induced apoptosis, increased hippocampal neuroplasticity, and upregulated gene expression of glial cell line–derived neurotrophic factor, among other suggested mechanisms.Liang 2009, Wang 2009, Xu 2010
An aqueous extract of the roots prolonged phenobarbital-induced sleeping time in mice with stress- or yohimbine-induced sleep deprivation, and had an antagonistic effect on caffeine-induced excitability and an antidepressant effect on induced chronic stress in mice.WHO 2007, Zhang 2008, Zhang 2009
Diabetes
Animal data
Decreased hyperglycemia was demonstrated in several studies in which diabetes had been induced in animals. Suggested mechanisms of action for aqueous or methanol R. glutinosa extracts, oligosaccharide, catalpol, rehmannioside D, or other polysaccharide extracts include decreasing glucose-6-phosphatase and fructokinase activity, decreasing plasma C-reactive protein, increasing hepatic glycogen content and pancreatic insulin release, and decreasing insulin resistance, as well as effects on nrf-2 activity and regulation.Miura 1997, Ren 2017, Waisundara 2008, WHO 2007, Zhang 2004, Zhang 2008 Additionally, protective effects were documented for diabetic nephropathy and obesity in animal models,Jiang 2008, Liu 2008, Zhang 2008 while other studies reported no effect on plasma cholesterol or triglycerides.Waisundara 2008
A hot water extract of Radix rehmanniae, an herbal medicine consisting of the dried roots and rhizomes of R. glutinosa Libosch. or R. glutinosa Libosch. Var. purpurea Makino (Scrophulariaceae),WHO 2007 showed hypoglycemic effects in a hyperglycemic silkworm model.Matsumoto 2016
Gastric ulcer
Animal and in vitro data
A reduction in ethanol-induced gastric mucosal damage was demonstrated with an aqueous extract of the root. Inhibition of gastric acid secretion was observed in animal studies.WHO 2007, Zhang 2008
Inflammatory/Immunomodulatory effects
Animal data
In animal studies, R. glutinosa has exerted effects on the immune system, including enhanced T-lymphocyte activity, reduction of histamine release and tumor necrosis factor production, and inhibition of hemolytic plaque-forming cells. The polysaccharide extracts jionoside and acteoside have been evaluated.Kim 1998, Sasaki 1989, WHO 2007, Zhang 2008 R. glutinosa root has shown anti-inflammatory and antiproliferative effects in experimental studies of psoriasis vulgaris.Zhang 2014
Clinical data
Research reveals no quality clinical data regarding the effects of Chinese foxglove on the immune system. In a poorly described clinical study, arthritis symptoms including reduced joint pain and swelling improved, and joint mobility increased.WHO 2007
Osteoporosis
Animal data
An in vivo study evaluating the effects of R. glutinosa extracts on ovariectomy-induced osteoporosis in rats showed an alleviation of decreased trabecular bone mineral density and increased cortical bone thickness and trabeculation of bone marrow spaces. R. glutinosa extracts may enhance bone metabolism in osteoporosis by stimulating the proliferation and activity of bone-forming osteoblasts and inhibiting generation and activity of bone-resorbing osteoclasts. The extract may also increase the expression of bone-related genes.Oh 2003
Clinical data
No clinical trials of R. glutinosa used alone for osteoporosis have been conducted. More than 100 clinical trials have used Radix rehmanniae in combination with other herbs to treat postmenopausal, senile, and secondary osteoporosis. However, trial methodologies are generally of poor quality, with limitations such as small patient sample size, short treatment duration, and poor clinical design. In addition, attribution of outcomes to a single ingredient is not possible.Liu 2017
Renal effects
Animal data
A protective effect of R. glutinosa plant ethanol extracts was demonstrated in animal models of renal failure and diabetic nephropathy.Lee 2009, Zhang 2004, Zhang 2008
Clinical data
In limited clinical studies by 1 group of researchers, R. glutinosa has been evaluated in the management of primary chronic glomerulonephritis, alone and in combination with the angiotensin receptor blocker irbesartan. Reductions in proteinuria and erythrocyturia were reported.Qiu 2013, Qiu 2014
Wound healing
Animal data
In animal models of diabetic foot ulcer, enhanced fibroblast cell viability occurred, as well as a trend toward decreased wound area and greater epithelialization.Lau 2009, Lau 2009
Clinical data
In combination with Radix astragali, Radix rehmanniae has been studied in the healing of diabetic foot ulcers (N=16). Improved wound healing and sensation at 6 months was reported in the study.Ko 2014
Dosing
Clinical studies are lacking to inform dosage. Common nonprescription polyherbal products contain varying amounts of Rehmannia root extract (range, 55 to 350 mg).
R. glutinosa acteosides given as two 200 mg capsules twice daily, both alone and in combination with irbesartan, for 8 weeks has been studied in primary chronic glomerulonephritis.Qiu 2013, Qiu 2014
Pregnancy / Lactation
Avoid use. Rehmannia has been used traditionally as an emmenagogue; however, no teratogenic or abortifacient effects were observed in rats following administration of a 70% methanol extract. An anti-implantation effect in female mice has been recorded.WHO 2007
Interactions
None well documented. Antiplatelet action has been described, based on in vitro studiesWHO 2007; however, antagonism of the effects of aspirin on coagulation time has also been reported.Zhang 2008 In mice, an aqueous extract prolonged sleeping time in phenobarbital-induced sleep, and also had an antagonistic effect on caffeine-induced excitability.Zhang 2008
Adverse Reactions
Some ingredients in a combination preparation have been suspected to cause liver toxicity, and the Pharmacopoeia of the Republic of Korea lists liver disease as a contraindication to Rehmannia use. Minor and transient adverse reactions have been reported and include GI reactions (eg, diarrhea, abdominal pain), edema, heart palpitations, fatigue, and vertigo.WHO 2007 In a study of more than 400 patients with primary chronic glomerulonephritis, adverse drug reactions reportedly occurred at a similarly low rate in the treatment group (0.4%) and control group (1.2%, P=0.3724).Qiu 2014
Toxicology
Information regarding toxicity is limited. Aqueous extracts of Radix rehmanniae were not mutagenic in Salmonella assay tests; however, intraperitoneal administration of the extract at doses 10 to 40 times human doses was mutagenic in mice.WHO 2007 An anti-implantation effect in female mice has been recorded; no teratogenic or abortifacient effects were observed in rats following administration of a 70% methanol extract.WHO 2007
Index Terms
- Radix rehmanniae
References
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