Dihydroberberine: a natural isoquinoline alkaloid with multiple pharmacological activities
1. Overview
Dihydroberberine (CAS number: 483-15-8) is a naturally occurring isoquinoline alkaloid with the molecular formula C20H19NO4 and a molecular weight of 337.3750 g/mol. It mainly comes from plants of the Berberis genus (Berberis spp.) and is a reduced derivative of berberine. In recent years, with the deepening of research on natural products, dihydroberberine has received widespread attention in the pharmaceutical industry due to its wide range of biological activities. Research has shown that it not only retains some of the pharmacological properties of berberine, but also exhibits superior activity or unique mechanisms in certain aspects.
Existing studies have revealed that dihydroberberine has anti-inflammatory, anti atherosclerosis, hypolipidemic, anti-tumor and potential antibacterial activities. Its mechanism of action involves multiple signaling pathways and molecular targets, such as inhibiting the expression of heat shock protein 90 (Hsp90), blocking the TLR4/MyD88/NF - κ B inflammatory pathway, and affecting hERG potassium ion channels. In terms of metabolic diseases, dihydroberberine showed the potential to improve glucose and lipid metabolism in animal models of obesity and insulin resistance induced by high-fat diet, suggesting its application prospect in the treatment of type 2 diabetes. In addition, it can enhance the sensitivity of lung cancer cells to Sunitinib, demonstrating a synergistic anti-tumor effect. These multifaceted activities make it a highly valuable lead compound for research.
2. Chemical structure and physicochemical properties
The chemical structure of dihydroberberine is based on the isoquinoline skeleton, and its SMILES is represented as: COc1ccc2c (c1OC) CN1CCc3cc4c (cc3C1=C2) OCO4. Structurally, it is a product of the reduction of double bonds at positions 8 and 13 on the C ring of berberine. This structural change significantly affects its electronic distribution and spatial conformation, which may alter its physicochemical properties and biological activity.
According to the provided pharmacological parameters, the molecular weight (MW) of dihydroberberine is 337.38 g/mol, which meets the Lipinski five rule requirement of "molecular weight less than 500". Its lipid water partition coefficient (LogP) is 4.04, indicating that the compound has high lipophilicity, which is beneficial for its penetration of cell membranes, but may also affect its water solubility. In fact, its water solubility is only 0.0043 mg/mL, making it a poorly soluble compound, which may be a major limiting factor for its oral bioavailability. The topological polar surface area (TPSA) is 40.16 Å ², which is relatively small and favorable for membrane permeation.
In terms of absorption and distribution, its Caco-2 cell permeability is 33.57 × 10 ⁻⁶ cm/s, which is relatively high, indicating its good intestinal absorption potential. More importantly, its blood-brain barrier (BBB) permeability is labeled as "high", which means that dihydroberberine may enter the central nervous system, providing the possibility for the development of drugs that act on the central nervous system, such as neuroprotective agents. The plasma protein binding rate (PPB) is as high as 91.56%, indicating that it mainly binds to proteins in the blood, which affects its free drug concentration and pharmacokinetics.
3. Plant sources and traditional applications
Dihydroberberine mainly comes from plants of the Berberis genus (Berberis spp.), commonly known as "three needles" or "prickly coptis". Berberis plants are widely distributed worldwide, especially in temperate regions of Asia and Europe. In the traditional medical system, especially in traditional Chinese medicine, Tibetan medicine, and Ayurvedic medicine, the roots, stem bark, and fruits of Berberis plants have been widely used for thousands of years.
According to traditional Chinese medicine theory, plants of the Berberis genus (such as porcupine thorn and three needles) have a cold nature and bitter taste, and have the effects of clearing heat, drying dampness, purging fire, and detoxifying. Commonly used for the treatment of damp heat diarrhea, jaundice, redness and swelling of the eyes, abscesses and sores. The core active ingredient is the isoquinoline alkaloid group represented by berberine. Dihydroberberine, as one of the metabolites of berberine in the body or a naturally occurring trace component in plants, is considered an important contributor to its pharmacological activity. Although dihydroberberine has not been directly isolated traditionally, the antibacterial, anti-inflammatory, and digestive regulating effects exhibited by plant extracts containing this component are highly consistent with the activity of dihydroberberine revealed by modern research, reflecting the mutual confirmation between traditional experience and modern science.
4. Pharmacological activity and mechanism of action
Dihydroberberine has diverse pharmacological activities, and its mechanism of action involves multiple targets and pathways, forming a complex network.
4.1 Anti inflammatory and immune regulatory activity
Dihydroberberine has a significant inhibitory effect on experimental colitis (such as DSS induced models). The core mechanism lies in Blocking the TLR4/MyD88/NF - κ B signaling pathway TLR4 is a key receptor for recognizing pathogen related molecular patterns, and its activation triggers downstream signals dependent on MyD88, ultimately leading to the activation of nuclear transcription factor NF - κ B, which in turn promotes the production of a large number of pro-inflammatory cytokines (such as TNF - α, IL-1 β, IL-6) and immunoglobulins. Dihydroberberine effectively reduces intestinal inflammation and tissue damage by intervening in this pathway. In addition, it can significantly reduce the expression of heat shock protein 90 (Hsp90). Hsp90 is an important molecular partner involved in the stability and function of various client proteins, including inflammation and tumor associated proteins. Inhibition of Hsp90 can simultaneously affect multiple pro survival and pro-inflammatory pathways.
4.2 Antitumor activity and sensitization effect
Dihydroberberine itself has anti-tumor activity. In addition to the Hsp90 inhibition mechanism mentioned above, research has also found that it can Increase the sensitivity of lung cancer cells to sunitinib Sunitinib is a multi-target tyrosine kinase inhibitor commonly used in the treatment of renal cell carcinoma and gastrointestinal stromal tumors, but drug resistance often leads to treatment failure. Dihydroberberine may exert a synergistic effect with sunitinib by regulating the tumor microenvironment, inducing tumor cell apoptosis, or inhibiting other compensatory survival pathways, providing a new approach to overcome tumor drug resistance.
4.3 Metabolic regulatory activity
In a rodent model of obesity and insulin resistance induced by a high-fat diet, dihydroberberine exhibits Improve body fat accumulation, tissue triglyceride accumulation, and insulin resistance The effectiveness. Its mechanism may involve activating the AMPK pathway, regulating gut microbiota, improving insulin signaling transduction, etc. These effects are similar to berberine, but due to its different pharmacokinetic properties, it may have advantages in certain aspects.
4.4 Antibacterial activity and related targets
Database information prompts dihydroberberine and Antibacterial Disease related and targeting five potential bacterial targets: GYRA (DNA gyrase A subunit), GYPB (possibly a typo or a protein related to cell division/morphology), DHFR (dihydrofolate reductase), MECA (possibly a protein associated with methicillin resistance), and PENA (possibly a penicillin binding protein). These targets are crucial for bacterial survival and reproduction.
* GYRA (DNA gyrase)It is a classic target of quinolone antibiotics, involved in bacterial DNA replication, transcription, and repair. Acting on this target can cause bacterial DNA damage and death.
* DHFR (dihydrofolate reductase)It is a key enzyme in the folate synthesis pathway and is essential for bacterial synthesis of nucleotides and amino acids. Trimethoprim (TMP) is a classic DHFR inhibitor.
* MECA and PENA The names of these two targets suggest that their effects may be related to bacterial cell wall synthesis. PENA may refer to penicillin binding proteins (PBPs), which are targets of β - lactam antibiotics; MECA may be associated with methicillin resistance, such as PBP2a encoded by the mecA gene. Dihydroberberine may exert antibacterial effects by interfering with cell wall synthesis or overcoming certain resistance mechanisms.
These target information collectively indicate that dihydroberberine may have broad-spectrum or antibacterial potential against specific drug-resistant bacteria, but its specific mechanism of action and efficacy spectrum need further experimental verification.
4.5 Effects on hERG Channels
It is worth noting that the description mentions that dihydroberberine "can inhibit the human ether related gene (hERG) channel". The hERG channel encodes the fast delayed rectifier potassium current (IKr) of the heart, which is crucial for repolarization of cardiac action potentials. Inhibition of hERG is a major risk factor for drug-induced acquired long QT syndrome and apical torsion ventricular tachycardia, and is an important cardiac safety evaluation indicator in drug development. However, there is a contradiction in labeling the "hERG_inhibition" item as "no" in the drug formulation parameter table. The possible scenario is that early studies observed inhibition, but subsequent more precise detection or no significant inhibition was shown at different concentrations; Or the data sources and criteria for different entries in the database may be inconsistent. This is crucial and requires clear evaluation through standardized electrophysiological experiments (such as patch clamp technology) in subsequent research and development.
5. Evaluation of drug properties
Based on the provided physicochemical and pharmacokinetic parameters, we can conduct a preliminary evaluation of the potential of dihydroberberine as a drug.
Lipinski's Five Rules Analysis：
1. Molecular weight (MW): 337.38<500,Comply with。
2. LogP：4.04 < 5，Comply with(Although approaching the upper limit).
3. Number of hydrogen bond donors (HBD): Based on the molecular formula C20H19NO4, it may be one (- NH - or - OH),Comply with（<5）。
4. Number of hydrogen bond acceptors (HBA): Structurally, it contains 4 oxygen atoms and 1 nitrogen atom, possibly 5,Comply with（≤10）。
Overall, dihydroberberine Basic compliance Lipinski's Five Rules possess the basic structural characteristics of drug like properties.
Advantage：
1. Good permeability High Caco-2 permeability and high BBB permeability indicate good potential for oral absorption and central distribution.
2. Clear pharmacological activity There is clear evidence of in vitro and in vivo activity in multiple disease fields such as anti-inflammatory, metabolic regulation, and anti-tumor.
3. Multi-target effect: May produce synergistic therapeutic effects by acting on multiple targets.
Challenges and Risks：
1. Extremely low water solubility(0.0043 mg/mL): This is the biggest obstacle to its development into oral formulations, which may result in irregular absorption and low bioavailability. Improvements need to be made through formulation techniques such as making nanocrystals, solid dispersions, cyclodextrin inclusion complexes, or prodrugs.
2. High plasma protein binding rate(91.56%): May lead to an increase in the required dosage for onset and increase the potential risk of drug drug interactions.
3. Potential toxicity risks：
* Genotoxicity The Ames test value is 1.2 (usually>2 is positive, but caution should be exercised when approaching 1), while the "chromosomal-aberration" is marked as "present", indicating a possible risk of chromosomal aberration, which needs to be confirmed through more comprehensive genetic toxicity testing (such as micronucleus test).
* allergenicity SkinSens "(skin sensitization) and" Resp_Sens "(respiratory sensitization) are both marked as" Yes ", indicating the need to pay attention to the risk of allergic reactions in industrial production and clinical use.
* Hepatotoxicity warning Ser_LT (alanine aminotransferase) and Ser_GGT (gamma glutamyltransferase) are marked as "Yes", indicating that they may have certain effects on the liver and require systematic liver toxicity assessment.
* Uncertainty of cardiac toxicity As mentioned earlier, the conflicting data regarding hERG inhibition must be clarified.
4. Treatment Index (MRTD)Annotated as' no 'may indicate a narrow window between its effective dose and toxic dose, requiring precise dose exploration.
6. Research Status and Application Prospects
At present, research on dihydroberberine is still in the preclinical stage, but a considerable amount of pharmacological activity data has been accumulated, revealing its potential in Chronic inflammatory diseases(such as inflammatory bowel disease, atherosclerosis)Metabolic diseases(Type 2 diabetes, non-alcoholic fatty liver, obesity) and neoadjuvant therapy The enormous potential of the field. Its unique antibacterial target information also provides new clues for the development of new antibacterial agents, especially for combination therapy strategies targeting drug-resistant bacteria.
Future research directions should focus on the following aspects:
1. In depth mechanism research Further elucidate the exact molecular targets and signaling networks of its anti-inflammatory, anti-tumor, and antibacterial properties, especially the direct validation of its effects on bacterial targets such as GYRA and DHFR.
2. Pharmacokinetic optimization Solving the problem of poor water solubility is the key to promoting its development. Developing new drug delivery systems or synthesizing derivatives/prodrugs with higher bioavailability is an important strategy.
3. Comprehensive security evaluation The systematic evaluation and clarification of its genotoxicity, hepatotoxicity, and cardiotoxicity (hERG inhibition) risks are the thresholds that determine whether it can enter clinical trials.
4. Exploration of clinical translation On the basis of improving preclinical research, design a reasonable clinical research plan to explore its safety and efficacy in specific indications (such as adjuvant therapy for colitis, combined with existing anti-tumor/hypoglycemic drugs).
In summary, dihydroberberine, as a natural product derived from traditional medicinal plants, has attracted widespread attention due to its multi-target and multi activity characteristics. Although it still faces challenges such as solubility and toxicity on the path of traditional Chinese medicine, through the transformation and optimization of modern medicinal chemistry and formulation methods, it is expected to be developed into a new drug or important lead compound for treating various complex diseases, fully reflecting the value of drug research and development from traditional wisdom to modern innovation.
