Rehmannia: What Is It And What Are The Benefits?

Rehmannia glutinosa is a traditional Chinese medicinal herb that has several medicinal benefits, such as in the treatment of diabetes, anemia, lung disease, neuropathy, osteoporosis, neuropathy, and even fat distribution. Several medical studies have confirmed these benefits.

The benefits of taking Rehmannia as a pharmaceutical treatment are far-reaching and bring together Western medicine and Traditional Chinese Medicine, providing a holistic approach to treating numerous medical conditions. In this article, we unpack the details and the evidence that proves and disproves the benefits of Rehmannia.

What Is Rehmannia Glutinosa?

Rehmannia refers to a herb of the Scrophulariaceae family, Rehmannia glutinosa, which is the species that comes from glutinous (referring to the root’s sticky consistency). It is distributed in the Chinese provinces of Henan, Shandong, Shan’xi, Shanxi, Hebei, Liaoning, Inner Mongolia, Jiangsu, Zhejiang, Hunan, Hubei, and Sichuan.

Primarily, it is cultivated in nature, on mountain slopes and trails from anywhere near sea level to 1100m altitudes. The comprehensive Chinese medicinal herb, Rehmannia glutinosa Libosch, was recorded in Chinese medical classics “Shennong’s Herba” and is considered a “top-grade” herb in China.

Three types of Rehmannia glutinosa are processed for medicinal purposes: Fresh Rehmannia root, Rehmannia dride rhizome, and prepared Rehmannia root.

Fresh Rehmannia root clears heat and promotes salivation. Rehmannia dride rhizome removes pathogenic heat from the blood, nourishes Yin (negative, dark, and feminine energy/phenomena), and promotes body fluid production. Prepared Rehmannia root has the effect of nourishing Yin while supplementing blood and benefitting marrow, and so on.

 Rehmannia glutinosa effectively functions as a drug that nourishes Yin and tonifies the kidney, which stores essence, dominates growth development and reproduction. It also regulates water metabolism and is closely related to the neuroendocrine system, according to Traditional Chinese Medicine theory.

This suggests that Rehmannia glutinosa has a wide variety of pharmacological actions and chemical compositions, with reports emerging in recent decades that it has active principles that affect the blood, immune, cardiovascular and nervous systems. It also has anti-tumor and anti-senescence functions, among many other applications.

Use In Traditional Chinese Medicine

Rehmannia glutinosa is a widely used herb used in Traditional Chinese Medicine that belongs to the Scrophulariaceae family. It has been taken to nourish Yin and invigorate the kidney, giving it high value in Traditional Chinese Medicine. More recently, countless pharmaceutical studies have been conducted to investigate the effects of Rehmannia (1).

More than 70 compounds, including iridoids, saccharides, amino acid, inorganic ions, and other trace elements, have been found in Rehmannia. And studies have shown that its active principles have many pharmaceutical effects on the blood, immune, endocrine, cardiovascular, and nervous systems.

The effective monomeric compounds or active parts of Rehmannia glutinosa have been screened to investigate its pharmaceutical actions. There is plenty of scientific data to support continued application and use for developing new drugs.

Potential Rehmannia Benefits

So, now that you know what Rehmannia is and how it is used, you’re going to want to know about the potential benefits that it could have for your body. There’s plenty of scientific evidence to testify to its healing properties. Let’s take a look at a few of them:

May Help Treat Diabetes

China has one of the highest rates of diabetes in the world, and Traditional Chinese Medicine is a popular treatment for various diseases. It is used in combination with Western medical practices to treat diabetes.

Rehmannia glutinosa Libosch has been used in China for thousands of years to nourish the body and treat diabetes. Medical research reveals that the polysaccharides from Rehmannia glutinosa Libosch have a P53 gene expression increasing effect, along with immunopotentiating and hypoglycemic effects (2).

The formula commonly used in Traditional Chinese Medicine to treat patients, the Rehmannia Six Formula, is made up of six herbs: Rehmannia glutinosa, Fructus Corni, Dioscorea sp. (D. alata, D. opposita, D. Batatas), Poria cocos, Alisma sp. (A. orientalis, A. plantago aquatica), and Paeonia suffruticosa (3).

Each herb is used to treat a different symptom of diabetes and the complications that arise from it. One example is the thirst-improving qualities of R. glutinosa and Fructus Corni.

You can also promote urination with P. cocos and A. orientalis/A. Plantago. D. alata/D. opposita/D. Batatas can lower plasma glucose levels, and Paeonia suffruticosa can treat inflammation. Studies have also shown that the Rehmannia Six Formula has improved diabetes when applied in experiments conducted on rats (4).

Furthermore, the Rehmannia Six Formula has exhibited benefits for people with glucose intolerance (5). And, while glucose intolerance does not necessarily only occur in people who have diabetes, it does increase your risk of developing type 2 diabetes.

The Rehmannia Six Formula can also increase the plasma level of adiponectin and improve insulin resistance (6). Another study found that oral administration of the Rehmannia Six Formula increased insulin sensitivity and delayed insulin resistance in rats.

However, another study into the effects of the Rehmannia Six Formula found its effects to disappear in the absence of Fractus Corni – although the rations of the Rehmannia Six Formula were different from those used in the other studies (7).

NOTE: There isn’t enough research into how Rehmannia might affect blood sugar levels, and therefore, people with diabetes should exercise caution and consult with a medical professional before taking Rehmannia.

May Help With Anemia (Including Chronic Aplastic Anemia)

A study into the function of dried and prepared Rehmannia glutinosa f. hueichingensis’ functionality as a treatment for anemic hemorrhagic mice and its role in fostering bone marrow cells CFU-S and CFU-E found that it can promote the recovery of blood deficient animals. It also proved that RBC. Hb expedites the multiplication and differentiation of CFU-S, CFU-E and thus proves markedly helpful to the generation of blood (8).

Rehmannia polysaccharide is also associated with stanozolol and can treat chronic anemia with additional effects such as accelerating symptom remission. And, the great advantage is that it doesn’t present any other side effects (9).

When used with other Chinese herbs to explore treatment methods for patients with severe aplastic anemia, Rehmannia also is effective for those failing in immunosuppressive therapy.

The study found that within 6-57 months of treatment, 12 patients (accounting for 19.4% of the study participants) were effectively cured of their aplastic anemia, while 14 (22.6%) were relieved of their symptoms, and 8(12.9%) showed marked improvements. 28 (45.2%) reported the treatment to be ineffective, which means that the total effective rate was 54.8% (10).

A study into the difference in the antithrombosis and hematopoietic effects of the Rehmannia Six Formula found that both DRR and PRR had hematopoietic effects, which was demonstrated by their abilities to ameliorate bone marrow nucleated cells and bone marrow tissue’s pathology (11).

The predicted activity of the compounds from two types of the Rehmannia Six Formula could therefore be considered potential candidates for anemia and thrombosis treatment (11).

Assistance With Lung Disease

Chronic Obstructive Pulmonary Disease

Research into the effects of a Chinese recipe consisting of angelica and Rehmannia root, tongfei mixture, on patients with chronic obstructive pulmonary diseases (COPD) found that ingestion led to improvements in the symptoms of nocturnal hypoxia, as well as lower levels of Pa CO2. Tongfei mixture is also an important supplement for oxygen therapy (12).

Asthma

Early research into the Traditional Chinese Medicine theories that Shen-reinforcement and Qi-supplementation are important for the treatment of asthma suggests that Bu Shen Fang Chuan (BSFC) and Bu Shen Yi Qi (BSYQ) showed promising results. However, the efficacy and safety require further investigation through a double-blind clinical trial (13). Nonetheless, both formulae had multiple advantageous outcomes for the neuroendocrine-immune system and are justifyingly used as replacement therapy for asthma.

Another explanation of the study examines Traditional Chinese Medicine theory’s assertion that the essence of Kidney and Qi are core concepts. Patients with kidney and Qi deficiencies would have weak voices or don’t want to talk. Patients with loud and powerful voices, on the other hand, are full of Kidney and Qi.

Therefore, chronic lung disease involves the kidney and the internal-external relationships between the lungs and the kidney. These assertions are important Traditional Chinese Medicine theories, and it is often observed that asthmatic patients have kidney and Qi deficiencies (13).

Another study found that the two formulae could reduce acute exacerbation rates, but they showed several beneficial effects on the neuroendocrine-immune system (14).

They improve the HPA axis function, modulate Th1 and Th2 balance, reduce psychological stress, and suppress proinflammatory cytokines. The study found both formulae to be safe and well-tolerated.

Bu Shen Fang Chuan (BSFC) was more effective at improving HPA axis functionality, while Bu Shen Yi Qi (BSYQ) was more effective as an antidepressant and for its immunomodulatory effects (14). Both formulae contain Rehmannia root.

Treating Osteoporosis

Dried Rehmannia glutinosa roots are a kidney-tonifying herbal medicine with an extensive history of treating joint diseases safely. The roots of Rehmannia glutinosa stimulants the proliferation of osteoblasts and inhibits osteoclasts’ generation and resorptive activities (15).

Yukmi-jihang-tang (seven kidney nourishing herbs) have also been reported to reduce bone resorption in vitro and in vivo due to their ability to inhibit the phosphorylation of peptide substrates (15). It has also recently been found that Rehmannia glutinosa roots promote the proliferation of osteoblasts of MC3T3-E1 cells.

It is important to note that dried and steamed Rehmannia glutinosa roots are applied differently in Traditional Chinese Medicine. Dried Rehmannia glutinosa roots could potentially regulate bone metabolism because of the main active constituents found in both dried and steamed Rehmannia glutinosa roots.

Therefore, dried Rehmannia glutinosa root extracts (DRGE) have been shown to prevent ovariectomized rat models of osteoporosis-induced bone loss. It also doesn’t require hormonal intervention such as estrogen. Thus, it could be a promising natural alternative for preventing postmenopausal osteoporosis. However, further investigation is required (15).

More research into the clinical usage and pharmacological effects of Rehmanniae Radix, either on its own or with other herbs, in Traditional Chinese Medicine, aimed to provide a comprehensive review of its efficacy in treating skeletal diseases and historical interpretations of the action of Rehmanniae Radix in osteoporosis (16).

It found that Rehmanniae Radix exerts anti-osteoporotic effects via regulating kidney and liver functions and improving blood circulation (16). This was demonstrated through 107 clinical trials into the effects of Rehmanniae Radix in conjunction with other herbs. Most trials demonstrated a high level of efficacy with no apparent adverse effects.

Nephropathy

Medical research into Rehmanniae Radix extracts on nephropathy found that it reduced the magnitude of increases in glucose, urea nitrogen, 5-hydroxymethylfurfural, and thiobarbituric acid (TBA)-reactive substance levels (17).

The effects were most prominent in the high blood glucose group, and it appears that dried Rehmanniae Radix extract could be a useful therapeutic agent for inhibiting diabetic nephropathy (17).

Another study into the aqueous extract of steamed Rehmannia glutinose root (ARR) found that it lessens renal functional parameters in the ischemia reperfusion-induced acute renal failure (ARF) in rats (18).

The renoprotective effect of Rehmannia glutinosa may also be mediated by suppressing the expression of angiotensin II and AT(1) receptors and by regulating TGF-beta1 and type IV collagen expression (19).

Another study into the use of Rehmannia complex decoction as a treatment for diabetic nephropathy investigated whether the six crude medicines containing Corni fructus would be effective without Corni fructus as a modified Rehmannia complex (20).

It found that the Rehmannia complex without Corni fructus was highly effective in the its treatment of diabetic nephropathy, while ethanol extracts provided greater effects with water extracts (20).

Therefore, the effective alleviation of diabetic nephropathy can be attributed to normalizing activated endothelin pathway systems, oxidative stress, and MMP 2.9 when combined with moderate hypoglycemic activity.

Fat Distribution

A study of rats fed Rehmannia-containing Liuweidihuang pills demonstrated that Rehmmania might decrease visceral fat deposits and significantly ameliorated visceral fat deposition in a type-2 diabetic model (21).

Neuropathy

A 10-day study of rats fed doses of 100mg/kg/day of the aqueous extract of Rehmannia-containing Liuweidihuang-tang found that it induced a reduction in the frequency of error and increases in neurogenesis in the hippocampal dentate gyrus. In other words, their memory formation improved. Data also suggests that this improved spatial learning ability (22).

Conclusion

Rehmannia is a natural herb that has been used as a treatment in Traditional Chinese Medicine for centuries. It contains more than 70 compounds and can be prepared in several ways, and can be an effective treatment primarily for diabetes and associated illnesses. It can also be an effective treatment for osteoporosis, anemia, lung diseases, and it can even help reduce visceral fat and improve cognitive functions.