Introduction/Overview
Natural products have always been an important source of innovative drug discovery, among which flavonoids have attracted much attention due to their broad biological activity and low toxicity. Sotetsuflavone (CAS number: 2608-21-1) is a flavonoid compound isolated from the Cycas revoluta plant in the Cycas family. In recent years, with the in-depth study of the pharmacological effects of natural products, cycad flavonoids have shown various biological activities, especially in the fields of anti-tumor and anti-inflammatory, showing great potential. Research has shown that sesquiterpenes can significantly inhibit the migration and invasion of non-small cell lung cancer (NSCLC) A549 cells, induce apoptosis and autophagy, and exert anti-tumor effects by regulating key factors such as HIF-1 α, VEGF, and matrix metalloproteinases (MMPs). In addition, it also showed significant protective effects in a mouse model of Crohn's disease like colitis, indicating its strong anti-inflammatory activity. This article aims to systematically review the chemical structure, plant sources, pharmacological activity, mechanism of action, pharmacological evaluation, and clinical application prospects of cycad flavonoids, in order to provide comprehensive scientific references for the in-depth research and development of this compound.
Chemical structure and physicochemical properties
Cycas flavanone is a typical flavonoid compound with a molecular formula of C30H18O10 and a molecular weight of 552.4910. Its structure is composed of two flavonoid units connected by C-C bonds, and this unique bimolecular structure is the basis for distinguishing it from single flavonoid compounds and endowing it with special biological activity. Its chemical structure contains multiple phenolic hydroxyl groups, which are closely related to its antioxidant and anti-inflammatory activities.
In terms of physical and chemical properties, the lipid water partition coefficient (LogP) of cycad flavonoids is 3.6494, indicating that they have a certain degree of lipophilicity. Its topological polar surface area (TPSA) is 170.8000 Å ², reflecting the proportion of polar functional groups (such as hydroxyl groups) in the molecule. The water solubility of this compound is low, about 0.0022 mg/mL, which may affect its oral bioavailability. Preliminary pharmacological predictions indicate that the ability of Cycas flavonoids to cross the blood-brain barrier is low, and there is no significant inhibitory effect on hERG potassium channels (suggesting a low potential risk of arrhythmia). Additionally, the Ames test result is 0.6 (usually considered negative if the value is less than 1.5), indicating a low risk of mutagenicity. These preliminary pharmacological parameters provide basic data for subsequent drug chemistry optimization.
Plant sources and extraction methods
The main source of flavonoids in Cycas revoluta comes from the leaves of Cycas revoluta, a plant in the Cycas genus of the Cycas family. Cycas is an ancient gymnosperm widely distributed in tropical and subtropical regions of Asia, often used as an ornamental plant. Its leaves contain abundant flavonoids, which are the main raw materials for extracting flavonoids from cycad.
At present, the extraction of flavonoids from plant materials mainly uses organic solvent extraction method. The common process includes: soaking or refluxing the dried and crushed cycad leaves with polar solvents such as methanol or ethanol, combining the extracts and concentrating them under reduced pressure to obtain the crude extract. Subsequently, the crude extract was separated and purified using column chromatography techniques such as silica gel column chromatography, polyamide column chromatography, or high-performance liquid chromatography. Usually, solvent systems with different polarities (such as chloroform methanol, petroleum ether ethyl acetate, etc.) are used for gradient elution. Based on thin layer chromatography (TLC) or high performance liquid chromatography (HPLC) monitoring, the fractions containing sesquiterpenes are collected and further purified by recrystallization or preparative HPLC to obtain high-purity sesquiterpenes monomers. In recent years, modern technologies such as ultrasound assisted extraction and microwave-assisted extraction have also been applied to improve extraction efficiency and yield. Standardized and large-scale extraction and purification processes are the prerequisite for ensuring its subsequent pharmacological research and application.
Pharmacological activity research
A large number of in vitro and in vivo studies have revealed the diverse pharmacological activities of sesquiterpenes, mainly focused on anti-tumor and anti-inflammatory fields.
1. Antitumor activity:
Cycas flavonoids exhibit significant inhibitory effects on various tumor cells, especially non-small cell lung cancer (NSCLC) cells. In the A549 cell model (human lung adenocarcinoma cells), sesquiterpenes can effectively inhibit cell proliferation, migration, and invasion ability. Its anti-tumor effect is closely related to inducing cell apoptosis and autophagy. Research has shown that this compound can upregulate pro apoptotic proteins (such as Bax), downregulate anti apoptotic proteins (such as Bcl-2), activate the Caspase cascade reaction, and thus initiate mitochondrial pathway mediated cell apoptosis. Meanwhile, it can also induce the expression of autophagy related protein LC3-II and promote the formation of autophagosomes.
2. Anti inflammatory activity:
Cycas flavonoids have shown strong anti-inflammatory effects in various inflammatory models. In the macrophage inflammation model induced by lipopolysaccharide (LPS), it can significantly inhibit the production of nitric oxide (NO) and prostaglandin E2 (PGE2). More importantly, in the mouse model of Crohn's disease like colitis induced by dextran sulfate sodium (DSS), treatment with sophocarpine can significantly reduce colon tissue damage, decrease disease activity index, reduce the production of pro-inflammatory cytokines, and have a protective effect on intestinal mucosa. This provides experimental evidence for its application in the treatment of inflammatory bowel disease (IBD).
3. Other activities:
In addition, the study also suggests that flavonoids from Cycas may have potential activities such as antioxidant and neuroprotective effects, but related research is still in the preliminary stage and further exploration is needed.
Mechanism of action and molecular targets
The multiple pharmacological activities of cycad flavonoids stem from their regulatory effects on multiple intracellular signaling pathways, and their molecular target network is complex and critical.
1. Mechanism of anti-tumor effect:
* Inhibition of epithelial mesenchymal transition (EMT): Cycas flavonoids can reverse the EMT process induced by factors such as TGF - β, upregulate epithelial markers (such as E-cadherin), downregulate stromal markers (such as N-cadherin, Vimentin), thereby inhibiting the migration and invasion of tumor cells.
* Regulating the HIF-1 α/VEGF pathway: In the tumor microenvironment, sesquiterpenes can inhibit the stability and transcriptional activity of hypoxia inducible factor-1 alpha (HIF-1 alpha), thereby downregulating the expression of its downstream target gene vascular endothelial growth factor (VEGF) and inhibiting tumor angiogenesis.
* Inhibition of matrix metalloproteinases (MMPs): This compound can reduce the expression and activity of MMP-9 and MMP-13, which are key enzymes for degrading extracellular matrix, promoting tumor invasion and metastasis.
* Inducing apoptosis and autophagy: By regulating the Bcl-2/Bax ratio, activating Caspase-3/-9, and modulating signaling pathways such as PI3K/Akt/mTOR and MAPK, tumor cell apoptosis and autophagic death are induced.
2. Anti inflammatory mechanism:
The anti-inflammatory effect of cycad flavonoids is mainly achieved by regulating the classic inflammatory signaling pathway, involving multiple key targets:
* Nuclear factor kappa B (NF - κ B) pathway: Inhibiting the nuclear translocation of NF - κ B p65 subunit reduces its binding activity with DNA, thereby downregulating the transcription of downstream pro-inflammatory factors such as TNF - α, IL-6, and IL-1 β.
* Signal transduction and transcription activator 3 (STAT3) pathway: Inhibit the phosphorylation activation of STAT3 and block its mediated inflammation and cell survival signals.
* Inducible nitric oxide synthase (iNOS/NOS2) and cyclooxygenase-2 (COX-2/PTGS2): Inhibiting the expression of iNOS and COX-2 at the gene and protein levels, reducing the excessive production of inflammatory mediators such as NO and PGE2.
* Inflammatory bodies and Caspase-1: Perhaps by inhibiting the activation of NLRP3 inflammasome and reducing the activation of Caspase-1 (CASP1), the maturation and release of IL-1 β and IL-18 may be inhibited.
* Ion channel: There are studies suggesting that it may act on pain and inflammation related ion channels such as transient receptor potential vanillic acid subtype 1 (TRPV1) and anchored protein subtype 1 (TRPA1), but the specific mechanism remains to be elucidated.
These multi-target action characteristics enable cycad flavonoids to inhibit inflammation and tumor progression from multiple links.
Evaluation of drug properties and pharmacokinetics
Although cycad flavonoids have shown good pharmacological activity in vitro and animal models, their pharmacological properties still need to be systematically evaluated.
1. Preliminary analysis of drug properties: As mentioned earlier, its molecular weight is moderate, but its LogP value is high and its water solubility is extremely low, which may lead to poor oral absorption and low bioavailability. A higher TPSA also suggests that its membrane permeability may be limited. The absence of hERG inhibition and Ames mutagenicity negativity are its advantages.
2. Pharmacokinetic (PK) challenges: At present, there are few reports on the pharmacokinetics of the flavonoids system in Cycas chinensis. Based on its dual flavonoid structure, it can be inferred that it may undergo first pass effects after oral administration and be widely metabolized in the intestine and liver (such as glucuronidation and sulfation). Its low water solubility can affect its dissolution and absorption in the gastrointestinal tract. How to improve its bioavailability is the key to future formulation development, such as using delivery technologies such as nanocrystals, liposomes, cyclodextrin inclusion, etc.
3. Metabolism and toxicity: It is necessary to conduct in-depth research on its main metabolites, metabolic enzymes (such as CYP450 enzyme system), and potential drug drug interactions in the body. Although preliminary toxicity tests (such as Ames test) have yielded good results, a comprehensive preclinical safety evaluation is still needed, including acute toxicity, long-term toxicity, reproductive toxicity, etc.
Clinical application prospects and prospects
As a natural product with multi-target activity, the clinical application prospects of cycad flavonoids mainly focus on the following directions:
1. Anti tumor adjuvant therapy: Especially for non-small cell lung cancer (NSCLC), sesquiterpenes can exert synergistic effects with existing chemotherapy drugs or targeted drugs by inhibiting EMT, angiogenesis, and metastasis related proteins, which may be used to improve the prognosis of advanced NSCLC patients and reduce metastasis recurrence. Its induction effect on autophagy also deserves attention in drug resistance research.
2. Treatment of inflammatory bowel disease (IBD): Its significant protective effect in DSS induced colitis model provides strong evidence for the development of novel plant drugs or lead compounds for the treatment of Crohn's disease and ulcerative colitis. Its multi-target anti-inflammatory properties may be superior to single target inhibitors.
3. Other chronic inflammatory diseases: Based on its wide range of anti-inflammatory targets, its potential applications in fields such as rheumatoid arthritis and neuroinflammatory diseases (such as Alzheimer's disease) can be explored in the future.
However, there are still many challenges to clinical application:
* Structural optimization: By modifying its structure through medicinal chemical methods, its water solubility and pharmacokinetic properties can be improved while retaining its activity.
* Delivery system development: Design a new nano drug delivery system to improve its targeting, stability, and bioavailability.
* Deep analysis of the mechanism of action: Using omics technologies (proteomics, metabolomics) and gene editing techniques to more accurately elucidate its direct targets and network pharmacology mechanisms.
* Preclinical and clinical studies: Complete the preclinical safety and efficacy evaluation of the system, and ultimately advance to the clinical trial stage.
Conclusion
Cycas flavonoids are a type of flavonoid compound with significant anti-tumor and anti-inflammatory activities isolated from the traditional plant Cycas. It acts on key nodes of tumor occurrence, development, and inflammatory response by regulating multiple signaling pathways such as NF - κ B, STAT3, HIF-1 α/VEGF, and MMPs, demonstrating the advantage of multi-target action. Although current research has revealed its enormous therapeutic potential, its inherent physicochemical properties (such as low water solubility) and incomplete in vivo pharmacokinetic behavior constitute the main bottlenecks for its drug conversion. Future research should focus on improving its drug properties through structural modifications and novel delivery strategies, and conduct in-depth preclinical pharmacological and toxicological evaluations. With the continuous deepening of research, cycad flavonoids are expected to become an important lead compound for the development of innovative anti-tumor or anti-inflammatory drugs, providing new treatment options for patients with related diseases.
