Introduction/Overview
Natural products have long been an important source of innovative drug discovery, and their structural diversity and wide range of biological activities provide valuable lead compounds for the treatment of various diseases. Terpene lactones, as an important family of natural products, have attracted much attention due to their significant pharmacological activities such as anti-inflammatory and anti-tumor effects. Umbelliprene, also known as 7- [(2E, 6E) -3,7,11-trimethyldodecane-2,6,10-triene-1-yl] oxycoumarin, is a typical furan coumarin terpenoid lactone with a CAS number of 23838-17-7. This compound was initially isolated from plants in the Umbelliferae family, and its unique chemical structure - a coumarin mother nucleus connected to a long-chain farnesyl side chain via an ether bond - endows it with unique physicochemical properties and biological activity.
In recent years, with the rapid development of modern pharmacology and molecular biology techniques, the anti-inflammatory activity and potential mechanism of action of umbelliferone have been deeply revealed. Research has shown that umbelliferone can exhibit strong anti-inflammatory potential by intervening in multiple key inflammatory signaling pathways and molecular targets, such as nuclear factor kappa B (NF - κ B), signal transduction and transcription activator 3 (STAT3), cyclooxygenase (COX), and the production of various inflammatory cytokines (such as TNF - α, IL-6). In addition to its anti-inflammatory effect, preliminary studies also suggest that it may have application value in fields such as anti-tumor and neuroprotection. However, its low solubility and complex in vivo metabolic behavior also pose challenges for its drug development. This article aims to systematically review the chemical properties, plant sources, pharmacological activities, molecular mechanisms of action, pharmacological evaluation, and clinical application prospects of umbelliferone, in order to provide comprehensive scientific references for the in-depth research and development of this compound.
Chemical structure and physicochemical properties
The molecular formula of Umbellifera ether is C24H30O3, with a molecular weight of 366.5010. Its core structure is a derivative of 7-hydroxycoumarin (umbelliferone), in which the hydroxyl group at position 7 is connected to a 15 carbon farnesyl group (2E, 6E) -3,7,11-trimethyldodeca-2,6,10-triene-1-yl) through an ether bond. This structure classifies it as an alkylated derivative of angular dihydrofuran coumarins (such as isopsoralen type) in linear furan coumarins, but its side chain is an unsaturated terpene long chain, while the very common isopentenyl short chain significantly affects its physicochemical properties.
The key physicochemical parameters determine its biological behavior and potential for drug development. The lipid water partition coefficient (LogP) of Umbellifera ether is as high as 6.8272, indicating its strong lipophilicity. Consistent with this, its water solubility is extremely low, about 0.0003 mg/mL, mainly attributed to its large hydrophobic farnesyl side chains. The topological polar surface area (TPSA) of the molecule is 39.44 Å ², which is relatively small, further confirming its hydrophobic properties. These properties collectively affect their absorption, distribution, and metabolism within living organisms. High lipophilicity usually facilitates the penetration of compounds through cell membranes, but may also lead to difficulties in their dissolution and transport in body fluids. It is worth noting that, based on its physicochemical properties, umbelliferone has a high blood-brain barrier (BBB) penetration ability, which provides the possibility for its potential treatment of central nervous system related diseases such as neuroinflammation. In the preliminary safety screening, the compound did not show significant hERG potassium channel inhibitory activity (low risk of arrhythmia), and the Ames test result was negative (0.0), indicating that it has no direct genotoxic mutagenesis risk, laying a preliminary safety foundation for its further development.
Plant sources and extraction methods
Umbelliferae ether is widely present in plants of the Apiaceae family, which is also the origin of its name. Common source plants include various species of the genera Ferula, Peucedanum, Seseli, and Heracleum. For example, in the resin or rhizomes of various types of Ferula (such as Ferula szowitziana, F. assafoetida), umbelliferone often exists as the main coumarin component. In addition, there have been sporadic reports in plants such as Rutaceae. The content of arbutin varies greatly in different plant parts (such as roots, resin, fruits) and species, which is influenced by various factors such as genetic factors, growth environment, and harvest season.
The extraction of umbelliferyl ether from plant materials is usually carried out using organic solvent extraction method. Due to its strong lipophilicity, commonly used solvents include low polarity solvents such as petroleum ether, ethyl acetate, chloroform, and dichloromethane. The classic extraction process is as follows: dry and crushed plant materials are subjected to cold soaking or hot reflux extraction using the above-mentioned solvents, and the extracted liquids are combined and concentrated under reduced pressure to obtain the crude extract. Subsequently, further separation and purification steps are required to obtain high-purity umbelliferyl ether. Column chromatography (CC) is the most commonly used purification technique, often using silica gel as the stationary phase and gradient elution systems such as petroleum ether ethyl acetate or n-hexane ethyl acetate. High performance liquid chromatography (HPLC), especially preparative HPLC, is commonly used for final purification and refinement. Thin layer chromatography (TLC) combined with fluorescent spots unique to coumarin compounds under ultraviolet light (365 nm) is an effective auxiliary method for tracking and identifying the compound. In recent years, some green extraction techniques such as supercritical fluid extraction (SFE) have also been explored for the extraction of such lipophilic natural products to improve efficiency and reduce the use of organic solvents. Chemical analysis of extracts is usually carried out using techniques such as mass spectrometry (MS), nuclear magnetic resonance (NMR, especially 1H NMR and 13C NMR) for structural confirmation.
Pharmacological activity research
The most notable pharmacological activity of umbelliferone is its powerful anti-inflammatory effect, which has been confirmed in various in vitro and in vivo inflammatory models.
In vitro research This indicates that umbelliferone can effectively inhibit the production of nitric oxide (NO) and prostaglandin E2 (PGE2) by macrophages (such as RAW264.7 cells) induced by lipopolysaccharide (LPS) or other stimulants. It can also dose dependently reduce the expression and secretion of various pro-inflammatory cytokines, including tumor necrosis factor - α (TNF - α), interleukin-6 (IL-6), interleukin-1 β (IL-1 β), etc. At the cellular level, umbelliferyl ether exhibits extensive inhibitory ability against inflammatory responses.
In vivo research Further verification of its anti-inflammatory effect. In mouse acute inflammation models, such as carrageenan or acetic acid-induced paw edema, administration of umbelliferone by gavage or intraperitoneal injection can significantly reduce tissue swelling. In chronic inflammation models such as the Freund's complete adjuvant (CFA) - induced arthritis rat model, treatment with umbelliferone not only alleviates joint swelling and pain, but also improves pathological damage to joint tissue, such as synovial hyperplasia and inflammatory cell infiltration. In addition, in some animal models of skin inflammation, allergic asthma, etc., umbelliferyl ether has also shown good therapeutic effects.
In addition to its core anti-inflammatory activity, Umbellifera ether also exhibits other potential pharmacological effects. Some studies suggest that it has antitumor Activity can inhibit the proliferation of certain cancer cell lines and induce apoptosis, which may be related to its anti-inflammatory properties and regulation of cell cycle related pathways. Its excellent blood-brain barrier penetration potential, combined with anti-inflammatory effects, has also triggered concerns about it neuroprotection The exploration of its role has shown certain effects in improving cognition and reducing neuroinflammation in animal models of neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. In addition, there are reports that it has auxiliary activities such as antioxidant and antibacterial properties. However, these studies on non anti-inflammatory activities are still in the preliminary stage and require deeper and more systematic validation.
Mechanism of action and molecular targets
The anti-inflammatory effect of Umbellifera ether is not achieved through a single target, but rather through the synergistic action of multiple targets and pathways, forming a complex network regulatory system. According to existing research, its mechanism of action mainly involves the regulation of the following key targets and signaling pathways:
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Inhibition of NF - κ B signaling pathway Nuclear factor kappa B (NF - κ B) is the core transcription factor in inflammatory response. Umbellifera ether can inhibit the degradation and phosphorylation of I κ B α protein induced by LPS and other stimuli, thereby preventing the nuclear translocation of NF - κ B p65 subunit. This directly leads to a reduction in transcription of a series of pro-inflammatory mediator genes downstream, including TNF-α、IL-6、IL-1β、 Inducible nitric oxide synthase (iNOS/NOS2) and cyclooxygenase-2 (COX-2/PTGS2)The regulation of NFKB1 (p105/p50) is the cornerstone of its extensive anti-inflammatory effects.
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Regulating the STAT3 signaling pathway Signal transducer and activator of transcription factor 3 (STAT3) is another important pro-inflammatory and pro survival pathway. Umbellifera ether can inhibit the tyrosine phosphorylation (such as Tyr705 site) and transcriptional activity of STAT3. The downregulation of STAT3 activity not only reduces the expression of inflammatory genes driven by it, but may also be related to its observed anti-tumor activity.
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Affects inflammasome activity The activation of inflammasomes (such as NLRP3) leads to the cleavage and activation of caspase-1 (CASP1), which in turn promotes the maturation and secretion of IL-1 β and IL-18. Research has shown that umbelliferone can inhibit the assembly and activation of NLRP3 inflammasomes, reduce the activity of caspase-1, and thus decrease the production of mature IL-1 β.
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Regulating the arachidonic acid metabolic pathway Umbellifera ether has an inhibitory effect on cyclooxygenase (COX) activity, especially on inducible COX-2 (PTGS2), and may also affect constitutive COX-1 (PTGS1). This directly reduces the synthesis of inflammatory mediator PGE2. In addition, it may also affect the metabolism of other lipid mediators.
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Intervention of pain related ion channels Transient receptor potential vanillic acid subtype 1 (TRPV1) and transient receptor potential anchor protein subtype 1 (TRPA1) are key ion channels involved in the perception of inflammatory pain. Umbellifera ether has been shown to act as a regulator (usually an antagonist) of these channels, reducing calcium ion influx and exerting analgesic effects, which is consistent with its performance in relieving inflammatory pain in an in vivo model.
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Direct antioxidant effect Although its antioxidant capacity may not be the main mechanism, the structure of umbelliferone may allow it to clear some reactive oxygen species (ROS), indirectly reducing the inflammatory amplification effect caused by oxidative stress.
In summary, Umbellifera ether acts simultaneously on NFKB1、STAT3、CASP1、PTGS1/2、TRPV1、TRPA1、NOS2、TNF A three-dimensional anti-inflammatory network was formed by targeting multiple targets, ranging from upstream signal transduction (NF - κ B, STAT3), to midstream inflammatory mediator synthesis (COX-2, iNOS), and downstream pain signal transduction (TRP channel). This multi-target characteristic enables it to effectively interrupt the cascade amplification effect of inflammation, but also brings complexity to the complete elucidation and selective optimization of its mechanism of action.
Evaluation of drug properties and pharmacokinetics
Although umbelliferone has significant pharmacological activities in vitro and in vivo, there are clear advantages and challenges in drug likeness, and systematic pharmacokinetic (PK) evaluation and formulation optimization are needed.
Advantage aspects Firstly, its molecular weight is moderate (<500), which conforms to the basic rules of drug likeness. Secondly, it is predicted that there will be no hERG inhibition or Ames mutagenicity, and the preliminary safety is good. Most importantly, its high lipophilicity (high LogP) and low TPSA endow it with excellent membrane permeability, great oral absorption potential, and efficient penetration of the blood-brain barrier, which is crucial for the treatment of central nervous system inflammatory diseases.
Main challenges：
1. Extremely low water solubility(0.0003 mg/mL): This is the biggest obstacle facing its development. Low solubility can lead to low oral bioavailability, unstable absorption, insufficient in vivo exposure, and difficulty in making injectable formulations.
2. Metabolic stability Containing coumarin mother nucleus and long-chain olefin structure, it may be easily metabolized by liver cytochrome P450 (CYP) enzyme system, especially CYP3A4 and CYP2C families, leading to significant first pass effects and short in vivo half-life.
3. Potential drug interactions As a derivative of coumarin, caution should be exercised regarding the risk of interaction with anticoagulant drugs such as warfarin (although whether umbelliferone itself has strong anticoagulant activity remains to be determined).
4. Lack of systematic pharmacokinetic data At present, there is very limited research on the in vivo ADME (absorption, distribution, metabolism, excretion) of umbelliferone. The key PK parameters such as absolute bioavailability, major metabolites, excretion pathways, and tissue distribution characteristics are still unclear.
Formulations and optimization strategies To overcome solubility issues, various advanced drug delivery strategies can be explored. For example:
- Nanoformulation technology Preparing it into nanocrystals, liposomes, polymer micelles, or solid lipid nanoparticles can significantly improve its apparent solubility and dissolution rate.
- Prodrug strategy Introducing hydrophilic groups (such as phosphate esters and amino acid esters) onto the 7-position ether bond or coumarin ring to make prodrugs, in order to improve water solubility, and then releasing the original drug through enzymatic interpretation in vivo.
- Eutectic/Eutectic Amorphous Technology Prepare eutectic or amorphous solid dispersions with suitable co morphs, disrupt their crystal structure, and improve solubility.
- Cyclodextrin inclusion technology Using water-soluble cyclodextrins such as sulfobutyl ether - β - cyclodextrin (SBE - β - CD) for inclusion, soluble complexes are formed.
Before further development, a systematic preclinical pharmacokinetic study must be conducted to clarify its PK characteristics in animal models such as rats and dogs, providing a basis for formulation design and dosing regimens.
Clinical application prospects and prospects
Umbellifera ether, as a multi-target natural anti-inflammatory lead compound, has shown broad application prospects in the treatment of various inflammation related diseases.
Potential indications：
1. Rheumatoid arthritis (RA) and osteoarthritis (OA)Its powerful inhibitory effects on joint inflammation, pain, and bone destruction make it promising for development as a novel anti rheumatic drug or in combination with traditional DMARDs.
2. Neurodegenerative diseases Given its ability to penetrate the blood-brain barrier and inhibit neuroinflammation, it has unique potential in the treatment of diseases such as Alzheimer's disease, Parkinson's disease, and multiple sclerosis.
3. Inflammatory pain By inhibiting COX-2 and TRPV1/TRPA1 channels, it may become a novel alternative or adjuvant to nonsteroidal anti-inflammatory drugs (NSAIDs) for the treatment of chronic inflammatory pain, and may reduce the gastrointestinal side effects of traditional NSAIDs.
4. Inflammatory bowel disease (IBD)Like Crohn's disease and ulcerative colitis, their anti NF - κ B and anti cytokine properties may help control intestinal mucosal inflammation.
5. skin disease Possible topical formulations can be explored for conditions such as psoriasis and atopic dermatitis.
Future research directions and challenges：
1. Research on Structural Optimization and Structure Activity Relationship (SAR)Systematically investigate the effects of substituents on coumarin parent nucleus and the length, saturation, and stereochemistry of farnesyl side chains on activity, selectivity, and drug formation. Intended to improve water solubility, metabolic stability, and target selectivity, while reducing potential toxicity.
2. In depth study on the mechanism of action Using chemical biology methods such as affinity fishing and molecular probes to search for protein targets directly acting on it, and elucidating the key nodes in its multi-target network. Study its specific effects in different cell types and disease models.
3. Comprehensive preclinical development Complete pharmacological, pharmacokinetic, and toxicological (acute toxicity, long-term toxicity, reproductive toxicity, etc.) evaluations that comply with regulations, and provide data support for its clinical trial application (IND).
4. Innovative formulation development As mentioned earlier, developing a novel drug delivery system that is suitable for its characteristics is a crucial step in pushing it into clinical practice.
5. Explore combination therapy Studying the synergistic effect of umbelliferone with existing standard therapeutic drugs may reduce their respective doses, minimize side effects, and improve efficacy.
Conclusion
Umbellifera ether is a unique natural product of farnesylated coumarins derived from plants in the Umbelliferae family. With its excellent multi-target anti-inflammatory activity, it has become a promising lead compound in the field of drug development. It exerts anti-inflammatory and analgesic effects at multiple levels by synergistically inhibiting key inflammatory signaling pathways such as NF - κ B and STAT3, downregulating the expression of various inflammatory mediators such as COX-2, iNOS, TNF - α, IL-6, and regulating the TRP pain channel. Its excellent membrane permeability and blood-brain barrier penetration ability further expand its potential application in the treatment of central nervous system diseases.
However, its extremely low water solubility and unclear pharmacokinetic properties are currently the main bottlenecks for its translation into clinical drugs. Future research should focus on structural optimization through medicinal chemistry, improving its bioavailability using modern formulation technology, and conducting systematic and in-depth preclinical efficacy, pharmacokinetics, and safety evaluations. With the advancement of these studies, umbelliferone is expected to gradually develop from a potential natural product molecule into a new therapeutic drug for treating chronic inflammatory diseases, neurodegenerative diseases, and inflammatory pain, providing new options to meet unmet clinical needs. The research process once again confirms the enormous value of discovering multi-target drug lead structures from natural products.
