Introduction/Overview
Natural products, as a treasure trove of drug discovery, have played a crucial role in the long history of humanity's fight against diseases. Among them, triterpenoids derived from plants have always been a hot topic in medicinal chemistry and pharmacology research due to their structural diversity and wide range of biological activities. Toosendanin, a triterpenoid compound of the limonoid class isolated from the traditional Chinese medicine Toosendanin, has been renowned for its unique insecticidal activity since its discovery. With the deepening of modern pharmacological research, the biological activity spectrum of naringenin continues to expand, and its multiple pharmacological effects such as anti-inflammatory, analgesic, anti-tumor, and antiparasitic have gradually been revealed, demonstrating enormous potential beyond traditional applications. Especially in the context of the still severe global situation in the prevention and control of parasitic diseases such as malaria, and the challenge of drug resistance faced by existing drugs, the research value of toon as a lead compound with a new mechanism of action is increasingly prominent. This article aims to systematically review the chemical structure, plant origin, pharmacological activity, mechanism of action, pharmacological evaluation, and clinical application prospects of naringenin, in order to provide comprehensive academic references for the in-depth development and transformation research of this natural product.
Chemical structure and physicochemical properties
The chemical structure of Toosendanin (C30H38O11) belongs to the highly oxidized limonoid triterpenoids. Its basic skeleton is a tetracyclic triterpene with multiple oxygen-containing functional groups, including epoxy, lactone, hydroxyl, and furan rings. These structural features are the material basis for its biological activity. Its CAS number is 58812-37-6 and its molecular weight is 574.6230.
From the analysis of physical and chemical properties, the lipophilic water partition coefficient (LogP) of toosendanin is 1.3106, indicating that it has a certain degree of lipophilicity, but not highly hydrophobic. Its topological polar surface area (TPSA) is as high as 165.2600 Å ², mainly attributed to the presence of a large number of oxygen atoms and polar groups in the molecule, indicating its strong molecular polarity, which may affect its transmembrane transport ability. The water solubility data (0.0549 mg/mL) confirms its low solubility in water, which is consistent with the characteristics of most triterpenoids and is also one of the key issues that need to be overcome in their formulation development. Preliminary pharmacological risk assessment shows that naringenin has no significant inhibitory effect on hERG potassium channels, indicating a low potential risk of arrhythmia; The Ames test result is 0.0, which preliminarily indicates that it has no mutagenicity in this testing system, providing an early positive signal for its safety evaluation. It is worth noting that its blood-brain barrier permeability is predicted to be "low", which means it may not easily enter the central nervous system. This may reduce central side effects for treatments primarily targeting peripheral or blood parasites such as malaria parasites, but if the target is located in the central nervous system, structural modifications need to be considered.
Plant sources and extraction methods
Chuanbansu mainly comes from the Meliaceae plant Chuanbansu（Melia toosendan The dried and ripe fruit of Sieb. et Zucc., also known as the traditional Chinese medicine "Chuanzhenzi". As a traditional Chinese medicine with a long history, Sichuan Melia seed is commonly used for soothing the liver, relieving heat, promoting qi circulation, relieving pain, and killing insects. Its insecticidal effect has been recorded in ancient books, which is highly consistent with the strong insecticidal activity of Sichuan Melia seed revealed by modern research.
The extraction of naringenin from plant materials is usually carried out using organic solvent extraction method. The classic process involves crushing the dried fruit of the Chinese toon tree and first defatting it with petroleum ether or n-hexane to remove weakly polar impurities such as oil and chlorophyll. Subsequently, medium polarity organic solvents such as ethyl acetate, ethanol, or methanol were used for repeated leaching or reflux extraction, and naringenin had higher solubility in such solvents. After concentration, the crude extract obtained needs to be purified through a series of chromatographic separation techniques, such as silica gel column chromatography, reverse phase column chromatography (such as ODS), and high performance liquid chromatography (HPLC). In recent years, some modern extraction techniques such as ultrasound assisted extraction, microwave-assisted extraction, and supercritical fluid extraction have also been explored and applied to the extraction of naringenin, in order to improve extraction efficiency, reduce solvent consumption, and protect thermally unstable components. The optimization goal of the extraction process is to achieve high yield and purity of naringenin, while ensuring its biological activity is maintained during the extraction process.
Pharmacological activity research
The pharmacological activity research of toosendanin began with its significant insecticidal effect and has expanded to multiple therapeutic fields.
- Antiparasitic activity This is the most classic and extensively studied activity of hesperetin. It has strong anti food, toxic, and growth inhibitory effects on various agricultural pests such as cabbage worms and diamondback moths, as well as medical parasites such as roundworms and tapeworms. Of particular note is its anti malaria activity. Research has shown that naringenin exhibits inhibitory activity against both chloroquine sensitive and resistant strains of malaria parasites, suggesting its potential to overcome existing resistance to antimalarial drugs.
- Anti inflammatory and analgesic activity Research has shown that naringenin exhibits significant anti-inflammatory effects in various animal models of acute and chronic inflammation, such as carrageenan induced foot swelling in rats and acetic acid induced increased intra-abdominal capillary permeability in mice. Its analgesic effect has also been confirmed in pain models such as hot plate method and acetic acid writhing method. These activities provide experimental evidence for their application in pain and inflammation related diseases such as arthritis and neuropathic pain.
- Antitumor activity In recent years, studies have found that toosendanin can inhibit the proliferation and induce apoptosis of many human tumor cell lines (such as liver cancer, breast cancer, lung cancer, leukemia cells). Its anti-tumor mechanism involves cell cycle arrest, mitochondrial dysfunction, increased production of reactive oxygen species, and regulation of apoptosis related signaling pathways.
- Neuromuscular pharmacological effects Early studies have indicated that naringenin can irreversibly block transmission at the neuromuscular junction, which is closely related to its insecticidal mechanism. However, it also suggests potential neurotoxicity, which needs to be closely monitored when developed as a systemic drug.
Mechanism of action and molecular targets
The multiple pharmacological activities of naringenin stem from its interactions with multiple molecular targets in the body, especially in the field of antiparasitic treatment, where its multi-target effects are particularly evident. This may be one of the reasons why it is not easily resistant to drugs. According to the provided target information, its mechanism of action can be summarized as follows:
- Interference with the transport and metabolism of malaria parasites: Acting on PFCRT The Plasmodium chloroquine resistance transporter protein may reverse or evade chloroquine resistance by affecting its function. Meanwhile, it may have an impact PFATP6(Plasmodium sarcoplasmic/endoplasmic reticulum calcium ATPase) disrupts intracellular calcium homeostasis, leading to parasite death.
- Inhibit key enzyme functions: Inhibition DHFR(Dihydrofolate reductase) interferes with the folate metabolism and nucleic acid synthesis of malaria parasites, which has the same target as the classical antimalarial drug ethambutol, but may have different binding sites. Correct CYP51 Inhibition of lanosterol 14 α - demethylase will disrupt the biosynthesis of ergosterol on the parasite cell membrane.
- Affects protein synthesis and stress response: By acting on EIF2A(Eukaryotic translation initiation factor 2A) and ribosomal protein RPS14、RPLP0 Directly inhibit the protein synthesis process of parasites. Meanwhile, with HSPA8 The interaction between members of the heat shock protein 70 family may interfere with the parasite's stress protection mechanism, making it more susceptible to environmental stress and drug attacks.
- Regulating energy metabolism and signaling pathways: Targeting PFKFB3(6-phosphofructose-2-kinase/fructose-2,6-diphosphatase 3), affects glycolysis flux and cuts off energy supply to parasites. In a wider range of models, it has also been reported that naringenin can affect GABAAR(gamma aminobutyric acid type A receptor), which may be related to its neuromuscular blockade and possible central effects such as anti anxiety and sedation. Although its BBB permeability is low, it may still play a role in the peripheral nervous system or under specific conditions.
In addition, the anti-inflammatory effect of naringenin is related to the inhibition of inflammatory signaling pathways such as NF - κ B and MAPK; The induction of tumor cell apoptosis is related to the regulation of Bcl-2/Bax ratio, activation of Caspase cascade reaction, and induction of endoplasmic reticulum stress.
Evaluation of drug properties and pharmacokinetics
Although naringenin has shown encouraging biological activity in vitro and animal models, its drug likeness still faces challenges, and systematic pharmacokinetic studies are crucial for its transformation.
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Absorption, distribution, metabolism, excretion (ADME)：
- absorb Lower water solubility and higher polar surface area may limit its oral bioavailability. Research has shown that its absolute oral bioavailability in rats is not high, suggesting that improvements may need to be made through formulation techniques (such as nanocrystals, liposomes, solid dispersions) or prodrug strategies.
- distribution As mentioned earlier, its blood-brain barrier permeability is poor, mainly distributed in tissues and organs with abundant blood flow. This characteristic may be advantageous when targeting peripheral parasites or tumors.
- Metabolism and excretion As a triterpenoid compound, naringenin is likely to undergo extensive phase I (such as CYP450 enzyme catalysis) and phase II (such as glucuronidation and sulfation) metabolism in the liver. The metabolites, main metabolic enzymes, and excretion pathways (bile or kidney) still need to be further elucidated, which is crucial for evaluating drug interactions and medication for patients with liver and kidney dysfunction.
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safety evaluation In addition to the negative results of hERG and Ames mentioned above, comprehensive toxicological studies are essential. The known neuromuscular toxicity of naringenin is a key focus of its preclinical safety evaluation. Acute, subacute, and chronic toxicity experiments, as well as comprehensive studies on reproductive toxicity and genetic toxicity, are essential steps in advancing clinical research. The determination of the therapeutic index (the ratio of effective dose to toxic dose) will directly determine its clinical application window.
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Formulation development Developing a suitable drug delivery system is the key to improving its drug properties in response to its poor solubility. For example, injectable nanomaterials may be used for emergency treatment of severe parasitic infections; Oral sustained-release formulations may increase their bioavailability and duration of action.
Clinical application prospects and prospects
The clinical application prospects of Chuan Lin Su are broad, but the road is tortuous and requires exploration and breakthroughs from multiple dimensions.
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As a lead compound for novel antiparasitic drugs At present, with the increasingly prominent problem of drug resistance in parasitic diseases such as malaria and schistosomiasis, the multi-target mechanism of action of naringenin makes it an ideal candidate for developing a new generation of antiparasitic drugs. Its characteristic of no cross resistance with existing drugs is highly attractive. Future research should focus on optimizing the structure of key parasitic targets, reducing toxicity (especially neurotoxicity) to mammals while maintaining efficient insect resistance, and improving selectivity index.
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Potential application in inflammation and pain management Its anti-inflammatory and analgesic activities provide new ideas for the development of drugs for diseases such as rheumatoid arthritis, osteoarthritis, and postoperative pain. Local topical preparations (such as gel and patch) can be explored to avoid possible toxicity caused by systemic administration and directly act on the affected part.
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Exploration in the field of anti-tumor therapy Although the anti-tumor activity of toosendanin is still in the preclinical stage, it suggests that it may be used as a chemotherapy sensitizer or adjuvant therapy drug. It is necessary to conduct in-depth research on its specific signaling pathways for anti-tumor effects and evaluate its synergistic effects with existing chemotherapy drugs.
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Development of agricultural green insecticides Based on its plant derived characteristics and efficient insecticidal activity, naringenin or its structurally optimized derivatives have clear and practical application prospects in the development of environmentally friendly biopesticides, which is in line with the direction of sustainable agriculture.
Looking ahead to the future, research on naringenin should focus on: ① using computer-aided drug design, structural biology, and other methods to elucidate its precise binding mode with key target proteins such as PFCRT and PFATP6, guiding rational drug design; ② Strengthen systematic pharmacokinetic and toxicological research, clarify the ADME characteristics and safety boundaries in the human body; ③ Actively developing modern drug delivery technologies and improving their physicochemical defects; ④ Explore its combination therapy with other drugs to enhance efficacy, reduce dosage and toxicity. Only through interdisciplinary and in-depth research can we truly transform naringenin from a potential natural product into innovative drugs or products that can be used for clinical treatment or agricultural production.
Conclusion
As a natural product with a long history of application, the modern pharmacological value of toosendanin is constantly being re recognized and explored. From traditional deworming drugs to lead compounds with multi-target antimalarial, anti-inflammatory, analgesic, and even anti-tumor potential, the research process of naringenin is a typical epitome of the discovery of innovative natural product drugs. Despite facing challenges such as solubility and toxicity in drug development, its unique chemical structure and diverse biological activity mechanisms endow it with irreplaceable research value. With the rapid development of modern science and technology, especially structural biology, computational chemistry, and new formulation technologies, we have reason to believe that through continuous in-depth research and rational modification of naringenin, we will be able to overcome its existing shortcomings, develop efficient and low toxicity new drugs, and make important contributions to human health and green agriculture development. The exploration of naringenin is not only a deep cultivation of a single compound, but also a vivid practice of modernizing and internationalizing the treasure trove of traditional Chinese medicine.
