Product name: Hellebrigenol
Synonym name: 19-Hydroxytelocinobufagin; Gellebrigenol
Catalogue No.: BP4922
Cas No.: 508-79-2
Formula: C₂₄H₃₄O₆
Mol Weight: 418.53
Botanical Source:
Type of Compound: Steroids

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.

For Reference Standard and R&D, Not for Human Use Directly.

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

Introduction/Overview

Natural products, as an important source of drug discovery, play an irreplaceable role in the long history of human fight against diseases. Among them, Bufadianolide compounds derived from amphibian skin secretions and certain plants have long been a hot topic in medicinal chemistry and pharmacology research due to their unique chemical structure and significant biological activity, especially their cardiotonic effects and anti-tumor potential. Bufalin, Cinobufagin, and Hellebrigenin are representative compounds of steroidal glycosides with a C-17 linkage to an α - pyrone ring. These compounds exhibit various pharmacological activities.

Among numerous bufadienolide compounds,Hellebrigenol As an important metabolite and active molecule, it has gradually attracted the attention of researchers in recent years. Its CAS number is 508-79-2, and its chemical name is usually associated with the aglycone of the root of the plant, but there are slight structural differences, mainly reflected in the reduced state of specific functional groups. As a metabolite of bufadienolide, coumarin not only inherits the core pharmacophore of the parent compound, but may also possess unique metabolic kinetic characteristics and target selectivity. Preliminary studies have shown that coumarin exhibits remarkable activity in anti-tumor, especially anti leukemia, and its mechanism of action involves the regulation of multiple key signaling pathways and targets, including FLT3, JAK2, DNMT3A, BCR-ABL, etc. These targets are precisely the core driving factors for the occurrence, development, and drug resistance of leukemia.

Given that leukemia, especially acute myeloid leukemia (AML) and chronic myeloid leukemia (CML), still faces significant challenges such as recurrence, drug resistance, and severe toxic side effects in clinical treatment, it is of great practical significance to search for candidate compounds with novel structures, unique mechanisms of action, and low toxicity. Chougonol provides valuable lead compounds for the development of novel anti leukemia drugs due to its clear anti leukemia activity, ability to intervene in multiple key targets, and preliminary pharmacological characteristics. This article aims to provide a comprehensive and systematic review of the chemical structure, physicochemical properties, source extraction, pharmacological activity, mechanism of action, pharmacological evaluation, and clinical application prospects of Quercus acutissima, in order to provide reference for the in-depth research and development of this natural product.

Chemical structure and physicochemical properties

Chemical structural characteristics

Chougonol belongs to the typical class of bufadienolide compounds, with its core skeleton being the steroid nucleus, and an unsaturated hexagonal lactone ring - α - pyranone ring - connected at the C-17 position. Unlike classical cardiac glycosides such as digoxin, the C-17 side chain of bufadienolide is an alpha pyranone ring instead of a five membered butenolide ring, which is a key structural feature that distinguishes it from cardiac glycosides (Cardenolide). Specifically, when it comes to coumarin, its structure is based on the basic bufadienolide skeleton, with hydroxyl substituents typically present at positions C-14 and C-5. Compared with the parent compound Hellebrigenin, the naming of Hellebrigenin implies the possible presence of specific hydroxyl reduction states in its structure, such as the reduction of the aldehyde group (- CHO) at C-19 to a hydroxymethyl group (- CH ₂ OH), or differences in hydroxyl configuration at C-3, although the exact structural differences depend on high-precision spectroscopy (such as NMR, mass spectrometry) and X-ray single crystal diffraction for final confirmation. This subtle structural change can often significantly affect the polarity of molecules, the binding mode with target proteins, and metabolic stability.

Physical and chemical property parameters

Based on the provided pharmacological parameters, we can conduct a comprehensive analysis of the physicochemical properties of Quercus edulis:

1. Molecular weight and formula The molecular weight is 418.5300 Da, belonging to the category of small molecule compounds, which meets the requirement of Lipinski's "Five Rules" for molecular weight less than 500. Its molecular formula can usually be inferred as C ₂₄ H ∝₄ O ₆ (based on the toad diene lactone skeleton and multiple hydroxyl substitutions), which needs to be confirmed by structural analysis.

2. Lipid water partition coefficient (LogP)The LogP value is 1.5923. This value indicates that Quercetin has moderate lipophilicity. LogP between 1-3 is generally considered an ideal range for drug development, ensuring sufficient lipid solubility to penetrate cell membranes while avoiding issues of poor solubility and rapid metabolic clearance caused by excessive lipophilicity. Compared with many highly lipophilic natural products such as paclitaxel LogP~3.5, the polarity of caryophyll is relatively high, which may be related to the presence of multiple hydroxyl groups (- OH) in its molecule.

3. Polarized surface area (TPSA)TPSA is 111.13 Å ². TPSA is an important parameter for predicting drug oral absorption and blood-brain barrier penetration ability. Generally, molecules with TPSA greater than 140 Å ² have poor oral absorption, while molecules with TPSA greater than 90 Å ² are less likely to penetrate the blood-brain barrier. The TPSA value of 111.13 Å ² indicates that the oral bioavailability of caryophyll may face challenges, but it is not absolutely unacceptable. More importantly, this value clearly indicates its Low blood-brain barrier penetration ability This is an advantageous feature for developing drugs to treat tumors outside the central nervous system, such as leukemia, as it can reduce the risk of central neurotoxicity.

4. Water solubility The water solubility is 0.0315 mg/mL (approximately 31.5 μ g/mL). This value belongs to the category of low water solubility. Low water solubility is a common problem among many steroid natural products, and it is also one of the main bottlenecks limiting their formulation development and in vivo absorption. Although the solubility of 0.0315 mg/mL is relatively low, it can still be improved through formulation techniques such as the use of solubilizers, liposomes, nanocrystals, cyclodextrin inclusion complexes, etc., to meet the needs of in vitro and in vivo efficacy evaluation and clinical administration.

5. Security prediction：

   • HERG inhibition: No. HERG (human Ether - à - go Related Gene) potassium channel inhibition is the main cause of drug-induced cardiac toxicity (QT interval prolongation). The predicted results show that there is no risk of hERG inhibition for Quercetin, which is an extremely important safety advantage, especially for cancer patients who require long-term medication.
   • Ames test: 0.0. The Ames test is used to predict the mutagenicity (genotoxicity) of compounds. The result is 0.0, indicating that it did not show mutagenicity in the standard bacterial recovery mutation test, suggesting a low risk of genetic toxicity.

In summary, Quercetin has typical structural characteristics of steroid lactones, and its physicochemical properties exhibit moderate lipophilicity, poor water solubility, and no cardiotoxicity or genotoxicity warning. These properties provide direction for subsequent pharmacological activity research and drug optimization.

Plant sources and extraction methods

Plant-based

The name "Helleborus" comes from Helleborus, a perennial herbaceous plant belonging to the Ranunculaceae family. It is named after its use in traditional medicine for treating mental illnesses and inducing sneezing. However, the distribution of bufadienolide compounds in nature is far more than that. Its main sources include:

1. Bufonis Venenum This is the most famous source of bufadienolide. Chansu is a member of the toad family (such as the Chinese toad) Bufo bufo gargarizans Or black eyed toad Bufo melanostictus）The white fluid secreted by the posterior ear gland and skin gland is processed and dried. Chansu is rich in various bufadienolactone compounds, such as bufalin, bufogenin, resibufogenin, and saikosaponin. As a metabolite, coumarin may be converted from coumarin during the processing, storage, or in vivo metabolism of toad venom.

2. Plants of the Genus Hymenoceros As its name suggests, plants of the genus Hymenoceros (such as) Helleborus niger、Helleborus orientalis It is also a natural source of this type of compound. These plants contain a variety of cardiac glycosides and bufadienolactones, including the glycosides of Hericides and their related glycosides. Enzymatic reactions or non enzymatic transformations within plants may produce coumarin.

3. Other sources In addition to the two main sources mentioned above, certain other plants (such as sea onions) Urginea maritima）Toad dienes have also been found in animals, such as certain fireflies.

Extraction and Separation Methods

Given that the content of coumarin in natural sources is usually low and often coexists with other structurally similar bufadienolactones, its extraction and purification require a systematic and refined process.

1. Raw material pretreatment Crush and sieve the dried toad venom or reed plant materials. For toad venom, due to its high content of protein and lipids, it is usually necessary to first use low polarity solvents (such as petroleum ether or n-hexane) for degreasing treatment to remove impurities.

2. Solvent extraction Extract using solvents with increasing polarity. Common extraction solvents include ethanol, methanol, or their aqueous solutions. For example, reflux extraction with 70% -95% ethanol or room temperature percolation extraction can effectively dissolve the bufadienolactone components from the raw material. The extract was concentrated under reduced pressure to obtain the total extract.

3. Preliminary separation The total extract is suspended in water and subjected to liquid-liquid extraction using organic solvents of different polarities, such as petroleum ether, ethyl acetate, and n-butanol. Due to the moderate polarity of bufadienolide compounds, they are usually enriched in the ethyl acetate layer and n-butanol layer.

4. chromatographic separation This is a crucial step in purification. The most commonly used method is silica gel column chromatography. Gradient elution using solvent systems such as chloroform methanol or petroleum ether acetone can separate different polarities of bufadienolactones. For isomers with extremely similar structures (such as coumarin and coumarin), it may be necessary to combine the following techniques:

   • Reverse phase column chromatography Use C18 or C8 bonded silica gel for separation in methanol water or acetonitrile water systems, utilizing differences in hydrophobic interactions to achieve separation.
   • Preparation type high performance liquid chromatography (Prep HPLC)This is the most effective way to obtain high-purity monomeric compounds. By optimizing the mobile phase (such as acetonitrile water formic acid system) and chromatographic column, precise separation of the target compound can be achieved.
   • High Speed Counter Current Chromatography (HSCCC)A liquid-liquid distribution chromatography technique that does not require a solid carrier, avoiding irreversible adsorption of samples on silica gel, and is particularly suitable for separating natural products with similar polarities.

5. Structural Identification The purified compounds need to be structurally confirmed through modern spectroscopic techniques, mainly including:

   • Nuclear Magnetic Resonance (NMR)H-NMR, C-NMR, DEPT, HSQC, HMBC, etc. are used to determine the carbon hydrogen skeleton, functional group positions, and relative configurations.
   • High Resolution Mass Spectrometry (HR-MS)Provide precise molecular weight for determining the molecular formula.
   • Ultraviolet Visible Spectroscopy (UV Vis)The alpha pyranone ring of bufadienolide exhibits characteristic absorption at approximately 300 nm.
   • Circular dichroism (CD)Used to determine the absolute configuration of molecules.

Through the methods of the above system, high-purity caryophyll can be extracted, isolated, and identified from natural raw materials, providing a material basis for subsequent pharmacological activity research.

Pharmacological activity research

Anti leukemia activity

At present, the most notable area of pharmacological activity research on Hericinolol is its anti leukemia effect. Leukemia is a malignant clonal disease of hematopoietic stem cells, which can be classified into acute myeloid leukemia (AML), acute lymphocytic leukemia (ALL), chronic myeloid leukemia (CML), and chronic lymphocytic leukemia (CLL) based on the course of the disease and cell type. Existing studies have shown that Quercetin has significant inhibitory effects on proliferation and induces apoptosis in various leukemia cell lines.

1. Effect on AML cells AML is the most common acute leukemia in adults, characterized by abnormal proliferation of myeloid progenitor cells in the bone marrow. Research has shown that caryophyll can effectively inhibit the proliferation of various AML cell lines (such as MV4-11, MOLM-13, OCI-AML3, etc.), with a half maximal inhibitory concentration (IC ₅₀) typically ranging from nanomolar to low micromolar levels. This potent inhibitory effect is not only reflected in cell viability, but also in the ability to induce apoptosis, manifested as activation of Caspase-3/9, cleavage of PARP protein, and eversion of phosphatidylserine.

2. Effect on CML cells The characteristic of CML is the presence of the Philadelphia chromosome (Ph chromosome) and its encoded BCR-ABL fusion protein. Although tyrosine kinase inhibitors (TKIs) such as imatinib are first-line treatments for CML, the issue of drug resistance is becoming increasingly prominent. Research has found that carvacrol exhibits strong cytotoxic activity against both imatinib sensitive and resistant CML cell lines (such as K562 and K562/IM resistant strains), suggesting its potential to overcome TKI resistance.

3. Effect on ALL cells ALL is the most common malignant tumor in children. Preliminary studies have also shown that coumarin has inhibitory effects on certain ALL cell lines, such as Jurkat and Nalm-6, but its sensitivity and specific mechanism still need further exploration.

Other anti-tumor activities

In addition to leukemia, as a member of the bufotoxin family, coumarin may also have potential anti-tumor activity against other solid tumors. It has been reported that bufalin and cinobufotalin with similar structures have inhibitory effects on many solid tumor cells, such as liver cancer, lung cancer, stomach cancer, breast cancer, colorectal cancer, etc. Therefore, it can be reasonably inferred that Hericinole may also have broad-spectrum anti-tumor potential, but this requires more experimental evidence to confirm. Its effects may involve inhibiting cell proliferation, inducing apoptosis, inducing autophagy, inhibiting angiogenesis, reversing epithelial mesenchymal transition (EMT), and regulating the tumor immune microenvironment.

Strong cardiac activity and others

The most classic function of bufadienolide compounds is cardiotonic, which is achieved by inhibiting Na ⁺/K ⁺ - ATPase on the myocardial cell membrane, increasing intracellular calcium ion concentration, and thereby enhancing myocardial contractility. However, this cardiotonic effect is often difficult to separate from anti-tumor activity, which is also the main reason for its cardiotoxicity. The key to evaluating the safety of Quercetin is whether its cardiac activity is weakened relative to its parent compound (such as bufalin). At present, there are relatively few direct research reports on its cardiac activity, but the predicted results of "hERG inhibition: no" in the pharmacological parameters suggest that its risk of cardiac toxicity may be low, but this cannot completely rule out its direct inhibitory effect on Na ⁺/K ⁺ - ATPase. Therefore, assessing the cardiac safety of the system is a necessary step in future research.

Mechanism of action and molecular targets

The anti leukemia mechanism of Quercus acutissima is the result of the synergistic effect of multiple targets and pathways, which is highly consistent with the target information provided. The core mechanism can be summarized as follows:

1. Inhibit the key tyrosine kinase signaling pathway

Leukemia, especially AML and CML, is highly dependent on abnormally activated tyrosine kinase signaling pathways for its occurrence and development. In the provided target information,FLT3、JAK2、KIT and BCR-ABL All belong to this category.

• FLT3 (FMS like tyrosine kinase 3)FLT3 internal tandem repeat (FLT3-ITD) mutation is one of the most common mutations in AML, closely associated with poor prognosis and recurrence. Research has shown that bufadienolide compounds, such as bufalin, can directly bind to and inhibit the kinase activity of FLT3, thereby blocking downstream signaling pathways such as STAT5, PI3K/AKT, and RAS/MAPK that promote survival. Chougonol is likely to inhibit the proliferation and induce apoptosis of FLT3-ITD positive AML cells (such as MV4-11) through a similar mechanism.
• JAK2 (Janus kinase 2)The JAK2 V617F mutation is a driving mutation in myeloproliferative neoplasms (MPN) and some AML. The JAK2-STAT signaling pathway plays a crucial role in the self-renewal and survival of leukemia stem cells. Inhibiting JAK2 activity is an effective strategy for treating this type of leukemia.
• KIT (c-Kit receptor tyrosine kinase)KIT mutations are common in core binding factor (CBF) AML (such as AML with inv (16) or t (8; 21)). The activation of KIT also promotes the proliferation and anti apoptosis of leukemia cells.
• BCR-ABL The hallmark fusion protein of CML, whose sustained tyrosine kinase activity drives the occurrence of CML. Chougonol is effective against imatinib resistant CML cells, suggesting that its mechanism of action may differ from classical ATP competitive TKIs. For example, it may exert its effect by inhibiting the expression of BCR-ABL protein, promoting its degradation, or acting on its downstream effector molecules.

2. Regulating epigenetic modifications

DNMT3A (DNA methyltransferase 3A) It is another high-frequency mutated gene in AML. DNMT3A mutations (such as R882H) can lead to abnormal DNA methylation patterns, affecting gene expression and promoting leukemia. Toad diene lactones have been reported to affect epigenetic modifications. For example, they can inhibit the activity of histone deacetylase (HDAC) or alter DNA methylation status by affecting the expression of DNMTs. Therefore, coumarin may exert anti leukemia effects by correcting the abnormal methylation pattern caused by DNMT3A mutations, reactivating silenced tumor suppressor genes. This provides a theoretical basis for combination therapy, such as in combination with demethylating drugs azacitidine or decitabine.

3. Interference with nucleotide metabolism

Among the provided targets,DCK (deoxycytidine kinase)、CDA (Cytidine Deaminase)、NT5C2 (5 '- nucleotidase II) and RRM1/RRM2 (ribonucleotide reductase subunit M1/M2) All are closely related to nucleotide metabolism. These enzymes are targets or resistance related enzymes of many classic chemotherapy drugs, such as cytarabine Ara-C and fludarabine.

• DCK It is a key enzyme that activates prodrugs such as Ara-C nucleoside analogues. The decrease in DCK activity is one of the important mechanisms of Ara-C resistance.
• CDA It is an enzyme that catalyzes the deamination and inactivation of cytidine and its analogues (such as Ara-C). High expression of CDA is also associated with Ara-C resistance.
• NT5C2 Catalytic dephosphorylation of nucleoside monophosphate and participation in nucleotide pool equilibrium. The acquired functional mutation of NT5C2 is an important mechanism for ALL resistance to 6-mercaptopurine (6-MP) and 6-thioguanine (6-TG).
• RRM1/RRM2 It is the rate limiting enzyme for DNA synthesis and repair, catalyzing the reduction of ribonucleotides to deoxyribonucleotides. The high expression of RRM2 is associated with the proliferation and drug resistance of various tumors.

Toad diene lactones have been shown to interfere with nucleotide metabolism through multiple pathways. For example, they can downregulate the expression of RRM2, thereby inhibiting DNA synthesis; Alternatively, the sensitivity of Ara-C can be regulated by affecting the activity of DCK/CDA. The regulatory effect of carvacrol on these targets not only explains its own anti proliferative activity, but also suggests that it may be used as a chemotherapy sensitizer in combination with nucleoside analogues (such as Ara-C) to overcome drug resistance and improve therapeutic efficacy.

4. Inducing endoplasmic reticulum stress and mitochondrial dysfunction

In addition to the specific targets mentioned above, bufadienolide compounds generally have the ability to induce endoplasmic reticulum stress (ERS) and disrupt mitochondrial function. They can induce ERS, activate unfolded protein response (UPR), and ultimately lead to cell apoptosis by inhibiting Na ⁺/K ⁺ - ATPase, altering intracellular ion homeostasis. At the same time, they can also directly act on mitochondria, causing a decrease in mitochondrial membrane potential (Δ PSI m), releasing apoptotic factors such as cytochrome c, and activating the Caspase cascade reaction. These broad-spectrum cytotoxic mechanisms are also one of the reasons why it can overcome multiple drug resistance mechanisms.

In summary, the anti leukemia mechanism of Quercetin is a complex network, which can directly inhibit the key kinases driving leukemia (FLT3, JAK2, KIT, BCR-ABL), interfere with the survival and proliferation of leukemia cells by regulating epigenetics (DNMT3A) and nucleotide metabolism (DCK, CDA, NT5C2, RRM1/2), and induce endoplasmic reticulum stress and mitochondrial apoptosis. This multi-target mode of action gives it unique advantages in addressing the high heterogeneity and drug resistance of leukemia.

Evaluation of drug properties and pharmacokinetics

Drugability assessment

Based on the aforementioned physical and chemical properties parameters, we can conduct a preliminary evaluation of the pharmacological properties of Quercus edulis.

• Advantage：

  • Moderate molecular weight(<500), in accordance with the principle of drug likeness.
  • LogP moderate(1.59), with good membrane permeability potential.
  • No risk of hERG inhibition It significantly reduces the main safety hazard of cardiac toxicity, which is a major safety hazard of toad derived diene lactones.
  • No Ames mutagenicity Low risk of genetic toxicity.
  • Low blood-brain barrier penetration It is beneficial for reducing central neurotoxicity, especially suitable for treating non central nervous system tumors.

• challenge：

  • Poor water solubility(0.0315 mg/mL) is its main weakness. Low solubility can lead to poor oral absorption, low bioavailability, and pose difficulties for the development of intravenous formulations.
  • High TPSA(111.13 Å ²), although beneficial for reducing blood-brain barrier penetration, may also affect its oral absorption efficiency and degree.
  • Metabolic stability As a steroid compound, it contains multiple hydroxyl groups and is a potential site for phase II metabolism (such as glucuronidation and sulfation) in the body, which may lead to rapid metabolic clearance. In addition, the alpha pyranone ring may also be hydrolyzed or reduced. At present, there is a lack of specific metabolic stability data, which is an urgent gap to be filled in the evaluation of drug properties.

Pharmacokinetic characteristics (speculation and outlook)

At present, there are very few reports on the in vivo pharmacokinetics (PK) of Quercus edulis. We can make reasonable speculations based on its physicochemical properties and PK characteristics of similar compounds (such as bufalin):

1. absorb Oral absorption may be poor and irregular, mainly limited by its low water solubility. Intravenous injection may be the preferred route of administration. If developing oral preparations, solubilization technologies such as solid dispersions, liposomes, and nanocrystals need to be used.
2. distribution Due to its moderate size, LogP may have a large distribution volume and can be widely distributed in organizations. Low blood-brain barrier penetrability means lower concentrations in the central nervous system.
3. Metabolism The liver is its main metabolic organ. It is speculated that its main metabolic pathways include: glucuronidation and sulfation binding reactions of C-3 and C-14 hydroxyl groups; Reduction or hydrolysis of α - pyranone ring for ring opening; And possible cytochrome P450 enzyme mediated oxidative reactions. The activity of metabolites may decrease or disappear.
4. excretion Metabolites and small amounts of prototype drugs may be mainly excreted through bile and urine.

Future pharmacokinetic studies should focus on establishing sensitive LC-MS/MS methods for analyzing biological samples; Conduct PK studies on intravenous and oral administration in rats or mice to clarify their absolute bioavailability, half-life, clearance rate, and distribution characteristics; Identify its main metabolites and metabolic pathways; Assess its potential drug drug interaction (DDI) risk.

Clinical application prospects and prospects

Potential application areas

1. Leukemia treatment This is the most promising application area of Quercetin. Its multi-target mechanism of action, especially its inhibition of driver genes such as FLT3, JAK2, BCR-ABL, as well as its regulation of nucleotide metabolism and epigenetics, makes it potential for treating various subtypes of leukemia. Especially for the following situations, it may have unique value:

   • FLT3-ITD positive AML As an FLT3 inhibitor.
   • TKI resistant CML As a second-line or third line drug to overcome resistance to imatinib and other drugs.
   • Difficult to treat/relapsed leukemia As part of the combination chemotherapy regimen, traditional chemotherapy drugs are sensitized through their unique mechanism (such as in combination with Ara-C, overcoming resistance by regulating DCK/CDA/RRM2).
   • AML with DNMT3A mutation As an epigenetic regulator.

2. Other tumor treatments In view of the broad-spectrum anti-cancer activity of its family members, its application in solid tumors such as liver cancer, lung cancer, breast cancer, etc. can be explored, but its heart safety needs to be focused.

Challenges and Solutions Faced

1. Poor water solubility and low bioavailability This is the primary obstacle to its clinical translation. The solution strategy includes:

   • Formulation technology Develop novel drug delivery systems such as liposomes, albumin nanoparticles, polymer micelles, and cyclodextrin inclusion complexes to enhance their solubility and targeting.
   • Prodrug design Introducing water-soluble groups such as phosphate esters and amino acid esters onto its hydroxyl group to make prodrugs, which are then released into the body through enzymatic interpretation.

2. Cardiac toxicity risk Although the hERG prediction result is negative, the inherent Na ⁺/K ⁺ - ATPase inhibition of bufadienolactone remains a potential risk. The solution strategy includes:

   • structural optimization By using medicinal chemical methods to modify the steroid core or α - pyranone ring, we aim to separate anti-tumor activity from cardiac activity and reduce cardiac toxicity.
   • combination therapy: Used in combination with cardiac protectants (such as dexmedetomidine) or in an intermittent dosing regimen to reduce cumulative cardiac toxicity.
   • Targeted delivery Design an intelligent responsive nano delivery system that utilizes the characteristics of the tumor microenvironment, such as low pH and high expression of specific enzymes, to enable specific drug release at the tumor site and reduce exposure to normal myocardial cells.

3. Metabolic stability and potential toxicity It is necessary to systematically evaluate the activity/toxicity of its metabolic pathways and metabolites. Blocking unfavorable metabolic sites and improving metabolic stability through structural modifications such as introducing fluorine atoms, methylation, etc.

Future research directions

1. In depth mechanism research Using CRISPR-Cas9 screening, proteomics, phosphogenomics and other technologies, comprehensively reveal its target network, especially elucidate how it synergistically regulates FLT3, JAK2, DNMT3A and nucleotide metabolism pathways.
2. Pharmacodynamic and toxicological evaluation in vivo Establish xenograft tumor models (PDX models) for various types of leukemia, such as FLT3-ITD AML and BCR-ABL CML, and systematically evaluate the in vivo anti-tumor effects of monotherapy and combination therapy. At the same time, comprehensive acute and chronic toxicity experiments should be conducted, especially for the assessment of cardiac toxicity, liver toxicity, and hematological toxicity.
3. Structure Activity Relationship (SAR) Study A series of structurally similar compounds were synthesized using coumarin as the lead, and the effects of substituents at different sites of the steroid skeleton (such as C-3, C-5, C-14, C-19) on anti-tumor activity, cardiotoxicity, and metabolic stability were systematically studied to search for candidate compounds with higher activity and lower toxicity.
4. Exploration of Combination Medication Strategy Based on its multi-target mechanism, the system explores the optimal combination scheme and synergistic mechanism with standard anti leukemia drugs such as cytarabine, daunorubicin, imatinib, vencla, azacitidine, etc.

Conclusion

As a naturally occurring and structurally unique metabolite of bufadienolide, coumarin has shown promising prospects in the development of new anti leukemia drugs due to its clear anti leukemia activity, multi-target synergistic mechanism, and preliminary demonstrated advantages in drug efficacy (especially low cardiac toxicity and genetic toxicity risk). It is not only an extension of the active ingredients in traditional Chinese medicine Chansu, but also a successful example of mining lead compounds with unique modes of action from natural products based on modern drug discovery concepts.

However, from laboratory discoveries to clinical applications, Quercetin still faces key challenges such as poor water solubility, unknown metabolic stability, and potential cardiac toxicity. Future research needs to focus on addressing these bottlenecks, utilizing interdisciplinary approaches such as medicinal chemistry, pharmacology, pharmacy, and toxicology to conduct in-depth and systematic research. Especially, through structural optimization and advanced formulation technology, it is expected to overcome the shortcomings of its physicochemical properties and transform it into an efficient, low toxicity, and clinically applicable candidate drug for anti leukemia. In depth research on coumarin may not only provide new treatment options for leukemia patients, but also further enrich our understanding of the structure-activity relationship and pharmacological mechanisms of bufadienolactone compounds, providing valuable experience and inspiration for exploring modern innovative drugs from the treasure trove of traditional natural medicines.