Product name: Rehmannioside D
Synonym name:
Catalogue No.: BP1202
Cas No.: 81720-08-3
Formula: C₂₇H₄₂O₂₀
Mol Weight: 686.613
Botanical Source: Rehmanniae Radix
Physical Description:
Type of Compound: Iridoids

Purity: 95%~99%
Analysis Method: HPLC-DAD or/and HPLC-ELSD
Identification Method: Mass, NMR
Packing: Brown vial or HDPE plastic bottle

Storage: Store in a well closed container, protected from air and light. Put into refrigerate or freeze for long term storage.
Whenever possible, you should prepare and use solutions on the same day. However, if you need to make up stock solutions in advance, we recommend that you store the solution as aliquots in tightly sealed vials at -20℃. Generally, these will be useable for up to two weeks.

The product could be supplied from milligrams to grams
Inquire for bulk scale.




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HPLC of Rehmannioside D

Storage conditions：Short-term storage at 2~8℃, long-term storage at -20 ~ -80℃

Introduction/Overview

In the treasure trove of traditional Chinese medicine, Rehmannia glutinosa（Rehmannia glutinosa Libosch, as one of the "Four Great Huai Medicines", has a long history of medicinal use and is commonly used for clearing heat, cooling blood, nourishing yin, and generating fluids. Its pharmacological activity is extensive, especially showing great potential in cardiovascular, neurological, and immune system diseases. With the advancement of modern separation and identification techniques, numerous chemical components in Rehmannia glutinosa have been elucidated, among which iridoid glycosides and carotenoid glycosides are the two main active ingredients. Rehmannianoside D, as a unique carotenoid glycoside, has gradually emerged from the numerous components of Rehmannia glutinosa in recent years and become a research hotspot. Its CAS number is 81720-08-3, mainly isolated from Rehmannia root. Preliminary studies have shown that digoxin D has significant antioxidant activity, which lays a theoretical foundation for its prevention and treatment of oxidative stress-related diseases, especially cardiovascular diseases. This article aims to systematically review the chemical structure, plant origin, pharmacological activity, mechanism of action, medicinal properties, and clinical application prospects of Dihuang glycoside D, in order to provide comprehensive scientific references for the in-depth research and development of this natural product.

Chemical structure and physicochemical properties

Dihuang glycoside D is a type of carotenoid glycoside compound. Its molecular formula is C ∝₀ H ₄₆ O ₁₉, and its molecular weight is 686.6130. Structurally, it is composed of a carotenoid glycoside linked to multiple glycosides. Carotenoids themselves are potent natural antioxidants, and glycosylation significantly alters their hydrophilic and lipophilic balance, thereby affecting their bioavailability and biological activity.

The key physicochemical property parameters are as follows:
* Lipid water partition coefficient (LogP)-3.0804. This value is negative and has a large absolute value, indicating that digoxin D has a high degree of hydrophilicity and is distributed very little in the lipid phase. This is mainly attributed to the polyhydroxy sugar groups connected in its molecular structure.
* Topological Polarity Surface Area (TPSA): 327.6000 Å ². The extremely high TPSA value further confirms the presence of a large number of polar regions (such as hydroxyl groups) on its molecular surface, which is the structural basis of its strong hydrophilicity.
* Water solubility：40.2162 mg/L。 Good water solubility is beneficial for its dissolution and transport in aqueous media such as body fluids.
* Blood-brain barrier permeability Predicted as low. Due to its extremely high polarity and molecular weight, digoxin D has a weak ability to passively cross the blood-brain barrier, and its direct action in the central nervous system may be limited or dependent on specific transporters.
* HERG inhibition Predicted as no. This indicates that at conventional doses, the risk of cardiac toxicity such as QT interval prolongation and apical torsion ventricular tachycardia caused by digoxin D is low, providing preliminary support for its cardiovascular safety.
* Ames test The predicted value is 0.0, indicating that it may not have direct genetic toxicity and has good safety.

In summary, Dihuang glycoside D is a highly polar, water-soluble, and high molecular weight glycoside compound. Its physicochemical properties determine that its pharmacokinetic behavior may be characterized by a small distribution volume and difficulty in penetrating biofilms.

Plant sources and extraction methods

Dihuang glycoside D is mainly derived from the plant Dihuang in the family Scrophulariaceae（Rehmannia glutinosa）Dry root tubers. Rehmannia glutinosa is divided into fresh Rehmannia glutinosa, raw Rehmannia glutinosa, and cooked Rehmannia glutinosa according to different processing methods, among which raw Rehmannia glutinosa and cooked Rehmannia glutinosa are its main medicinal forms. Research has shown that the content of Dihuang glycoside D is relatively low in Dihuang root and belongs to trace components. Its content is significantly affected by the place of origin, cultivation variety, harvest season, and processing methods.

At present, the extraction and separation of D-glucoside from Rehmannia glutinosa mainly follow the following process:
1. Extract Solvent extraction method is usually used. Due to the strong hydrophilicity of Dihuang glycoside D, water, methanol or ethanol aqueous solutions of different concentrations are commonly used as extraction solvents. Ultrasound assisted extraction and heating reflux extraction are commonly used techniques to improve extraction efficiency.
2. Enrichment and Coarse Separation After the extraction solution is concentrated under reduced pressure, the resulting extract is often subjected to gradient extraction using organic solvents such as petroleum ether, ethyl acetate, and n-butanol in sequence. Dihuang glycoside D is mainly enriched in the n-butanol extraction site and aqueous layer due to its strong polarity.
3. Separation and purification Further chromatographic separation of the parts rich in digoxin D is the key to obtaining pure products. Macroporous adsorption resin column chromatography (such as D101, AB-8) is often used for preliminary decolorization and impurity removal, and then repeated separation is performed by silica gel column chromatography, reverse phase silica gel column chromatography (such as ODS-C18), dextran gel column chromatography (such as Sephadex LH-20), etc. Ultimately, high-performance liquid chromatography (HPLC), especially preparative HPLC, is the most effective means of obtaining high-purity digoxin D monomers. Its identification mainly relies on spectroscopic techniques such as mass spectrometry (MS) and nuclear magnetic resonance (NMR, including ¹ H-NMR and ¹ ³ C-NMR).

In the future, developing efficient and environmentally friendly extraction and separation processes, such as high-speed countercurrent chromatography technology, is of great significance for achieving large-scale preparation of D-glucoside.

Pharmacological activity research

A large number of in vitro and in vivo studies have revealed the multifaceted pharmacological activities of Rehmannia glutinosa D. Its core revolves around antioxidant activity and extends to multiple fields such as cardiovascular protection.

1. antioxidant activity This is the most basic and clear activity of Dihuang glycoside D. In chemical systems, it can effectively scavenge DPPH radicals, ABTS ⁺ radicals, and superoxide anions, demonstrating strong free radical scavenging ability. In cell models, digoxin D can significantly alleviate oxidative stress induced by hydrogen peroxide (H ₂ O ₂), high glucose, or other stimuli, reduce intracellular reactive oxygen species levels, increase the activity of endogenous antioxidant enzymes such as superoxide dismutase, catalase, glutathione peroxidase, etc., and protect cells from oxidative damage.

2. Cardiovascular protective effect：

   • Endothelial protection Oxidative stress is the initiating factor of endothelial dysfunction. Dihuang glycoside D protects endothelial cells from damage and maintains the normal function of endothelial nitric oxide synthase through its antioxidant effect, thereby ensuring the production of nitric oxide and promoting vasodilation.
   • anti-inflammatory Cardiovascular disease is often accompanied by chronic inflammation. Research has shown that digoxin D can inhibit endothelial cell inflammation induced by inflammatory factors such as tumor necrosis factor - α and downregulate the expression of inflammatory mediators.
   • Anti atherosclerosis Through the combined effects of endothelial protection, antioxidant and anti-inflammatory, rehmannin D may inhibit the formation of early atherosclerosis. Its effect of reducing the expression of vascular cell adhesion molecules helps to reduce the adhesion and infiltration of monocytes to the endothelium.
   • Myocardial protection In animal models of myocardial ischemia/reperfusion injury, pretreatment with digoxin D can reduce myocardial infarction area and improve cardiac function. Its mechanism is related to reducing oxidative stress, inhibiting cell apoptosis, and regulating autophagy.

3. Other potential activities Based on its antioxidant properties, rehmannin D also shows potential research value in diabetes complications (such as diabetes nephropathy, retinopathy), neurodegenerative diseases and liver protection, but there are relatively few relevant reports, which need further exploration.

Mechanism of action and molecular targets

The cardiovascular protective effect of Dihuang glycoside D is not achieved through a single pathway, but through a complex network of target systems, whose core mechanism is closely related to antioxidant stress and involves multiple key signaling pathways and molecular targets.

1. Core pathway: Nrf2/ARE antioxidant pathway Nuclear factor E2 related factor 2 (Nrf2) is the overall switch for cellular antioxidant defense. Under oxidative stress, digoxin D may promote the translocation of Nrf2 from the cytoplasm to the nucleus, binding to antioxidant response elements, thereby initiating the transcriptional expression of a series of downstream phase II detoxifying enzymes and antioxidant proteins (such as HO-1, NQO1), which is one of the core molecular mechanisms for its cell protective effect.

2. Key molecular target analysis：

   • Endothelial function and inflammation related targets：
     • NOS3 Endothelial nitric oxide synthase and digoxin D protect their activity, maintain NO bioavailability, and ensure vasodilation function.
     • ICAM1 and VCAM1 Intercellular adhesion molecule-1 and vascular cell adhesion molecule-1. Rehmannin D can inhibit its expression, thereby reducing the adhesion of leukocytes to activated endothelium, and playing an anti-inflammatory and anti atherosclerosis role.
     • SELP P-selectin, also involved in leukocyte rolling and adhesion, is a potential target for its anti-inflammatory effects.
   • Metabolic and signal transduction related targets：
     • PPARG Peroxisome proliferator activated receptor gamma, an important nuclear receptor involved in regulating glucose and lipid metabolism and inflammatory response. Activation of PPARG can help improve insulin resistance and inhibit vascular inflammation, and digoxin D may serve as its modulator.
     • AKT1 Protein kinase B is a key node in the PI3K/Akt survival signaling pathway. Activation of Akt can inhibit cell apoptosis and promote cell survival. Dihuang glycoside D may exert myocardial and endothelial protective effects by upregulating p-Akt levels.
   • Cardiovascular regulation related targets：
     • ACE Angiotensin converting enzyme, a key enzyme in the renin-angiotensin system. Inhibiting ACE activity is a classic antihypertensive strategy. Whether Dihuang glycoside D has ACE inhibitory activity is a potential research direction for its antihypertensive mechanism.
     • ADRB2β 2-adrenergic receptors regulate vasodilation and cardiac function. Dihuang glycoside D may affect cardiovascular tension by regulating this receptor.
     • KCNH2 Encoding hERG potassium channel alpha subunit. The prediction shows that digoxin D has no inhibitory effect, which supports its cardiac safety from a negative perspective.
     • SLC8A1 Sodium calcium exchangers play a crucial role in the calcium homeostasis and excitation contraction coupling of myocardial cells. Regulating its function may affect myocardial contractility and the occurrence of arrhythmia.

In summary, Dihuang glycoside D forms the "network pharmacology" basis for its cardiovascular protection through multi-target and multi pathway synergistic effects.

Evaluation of drug properties and pharmacokinetics

Although the pharmacological activity of Dihuang glycoside D is clear, its drug like properties face certain challenges, mainly due to its unique physicochemical properties.

1. absorb High polarity (low LogP, high TPSA) and high molecular weight (>500) may severely limit its passive diffusion through the gastrointestinal epithelial cell membrane, resulting in lower expected oral bioavailability (BA). It may require active transporters on intestinal epithelial cells, such as glucose transporters, to be effectively absorbed.
2. distribution The predicted blood-brain barrier permeability is low, which means it is difficult for it to enter the central nervous system and exert its effects. Its high water solubility may result in a smaller distribution volume, mainly distributed in blood and extracellular fluid.
3. Metabolism and excretion As a glycoside compound, digoxin D is likely to be hydrolyzed by glycosidases in gut microbiota or tissues in the body, producing aglycones (carotenoids) and glycosides. The lipid solubility of aglycones is enhanced, which may have different activities and metabolic fates. The prototype drug and its metabolites may mainly be excreted through the kidneys (urine).
4. Preliminary evaluation of safety Based on computational predictions, Dihuang glycoside D has no hERG inhibition or Ames mutagenic risk, indicating its good cardiac safety and genotoxic safety margin. However, a comprehensive preclinical safety evaluation (such as acute toxicity, chronic toxicity, reproductive toxicity, etc.) has not been systematically reported, which is a gap that must be filled before its application.

Improvement strategy To improve its medicinal properties, the following strategies can be considered: ① Prodrug design Esterification and other modifications are carried out on the hydroxyl groups on the sugar group to temporarily increase lipid solubility, improve absorption, and then hydrolyze into the active form in vivo. ② New drug delivery system Develop delivery systems such as liposomes, nanoparticles, and self microemulsions to encapsulate digoxin D and enhance its membrane permeability and stability. ③ Simplification and Modification of Structure Simplify or modify the sugar chain while retaining the pharmacophore, and search for derivatives with similar activity but better drug properties.

At present, there is a severe lack of pharmacokinetic research data on the D-system of Rehmannia glutinosa, which is a key direction for future research.

Clinical application prospects and prospects

The research and application prospects of Dihuang glycoside D are broad, but also full of challenges.

1. As a dietary supplement/health food This is the most likely path to be implemented first. With its clear natural sources and antioxidant activity, health products can be developed to assist in regulating blood lipids, blood pressure, and maintaining cardiovascular health. The description that it can be used to study its efficacy as a supplement is based on this.
2. As a prescription drug development：
   • indication It mainly focuses on the prevention and auxiliary treatment of cardiovascular diseases, such as atherosclerosis, hypertension, and auxiliary drugs for myocardial ischemia reperfusion injury. It can also be extended to chronic diseases closely related to oxidative stress, such as diabetes vascular complications.
   • development mode It is more likely to be declared in the form of "herbal medicine" or "natural medicine" compound, as one of the quality marker components in Rehmannia glutinosa medicinal materials or Rehmannia glutinosa extracts, for standardized production and new drug research and development. As a single ingredient innovative drug development, it is necessary to overcome the aforementioned bottleneck of drug development, with large investment and long cycle.
3. combination therapy Dihuang glycoside D can be used in combination with other cardiovascular drugs with different mechanisms of action, such as statins and ACEIs, to exert synergistic antioxidant and organ protective effects, which may reduce the side effects or dosage of the main drug.
4. Future research directions：
   • In depth mechanism research Using techniques such as gene knockout/knockdown, molecular docking, and surface plasmon resonance, clarify its direct interactions and regulatory details with key targets such as PPARG and AKT1.
   • Systematic pharmacokinetic study Conduct ADME research in animals to clarify their absolute bioavailability, major metabolites, tissue distribution, and excretion pathways.
   • Preclinical and clinical research Complete standardized GLP toxicology evaluation and design rigorous clinical trials to verify its effectiveness and safety in humans.
   • Structure based optimization Combined with computer-aided drug design, carry out reasonable chemical modifications to balance activity and drug properties.

Conclusion

Dihuang glycoside D, as a representative carotenoid glycoside in Rehmannia glutinosa, is based on its significant antioxidant activity and exhibits clear cardiovascular protective potential by acting on multiple cardiovascular related targets such as NOS3, ICAM1, PPARG, AKT1, etc. Its natural source and predicted good safety add advantages to its application. However, the oral absorption and bioavailability challenges posed by its highly hydrophilic physicochemical properties are the key bottlenecks restricting its conversion into drugs. Future research needs to clarify its precise molecular mechanism, improve its pharmacokinetics and safety evaluation system, and actively use modern pharmaceutical and medicinal chemistry methods to improve its drug properties. With the deepening of interdisciplinary research, Dihuang glycoside D is expected to develop from an active ingredient in traditional Chinese medicine into an innovative drug or high-performance health product for the prevention and treatment of oxidative stress-related cardiovascular diseases, achieving a leap from traditional wisdom to modern medical applications.