Partial Activation and Inhibition of TRPV1 Channels by Evodiamine and Rutaecarpine, Two Major Components of the Fruits of Evodia rutaecarpa

Application of capsaicin and calcium phosphate-loaded MOF system for tumor therapy involving calcium overload

Calcium overload therapy refers to the condition of intracellular Ca2+ overload, which causes mitochondrial damage and leads to the uncontrolled release of apoptotic factors into the cytoplasm through the open mitochondrial permeability pore. Based on this, it is playing an increasingly important role in the field of oncology due to its good efficacy and small side effects. However, the regulation of calcium homeostasis by cancer cells themselves, insufficient calcium ions (Ca2+) in tumor sites and low efficiency of calcium entering tumor have limited its efficacy, resulting in unsatisfactory therapeutic effect. Therefore, a novel CAP/BSA@TCP-ZIF-8 nanoparticle drug carrier system was constructed that can provide Ca2+ from exogenous sources for pH-controlled degradation and drug release at the same time. Both in vivo and in vitro experiments have proved that the nanomaterial can activate TRPV1 channels and provide exogenous Ca2+ to cause Ca2+ overload and apoptosis, thus achieving anti-tumor effects.

Capsaicin Enhanced the Efficacy of Photodynamic Therapy Against Osteosarcoma via a Pro-Death Strategy by Inducing Ferroptosis and Alleviating Hypoxia

Ferroptosis, a novel form of nonapoptotic cell death, can effectively enhance photodynamic therapy (PDT) performance by disrupting intracellular redox homeostasis and promoting apoptosis. However, the extremely hypoxic tumor microenvironment (TME) together with highly expressed hypoxia-inducible factor-1α (HIF-1α) presents a considerable challenge for clinical PDT against osteosarcoma (OS). Hence, an innovative nanoplatform that enhances antitumor PDT by inducing ferroptosis and alleviating hypoxia is fabricated. Capsaicin (CAP) is widely reported to specifically activate transient receptor potential vanilloid 1 (TRPV1) channel, trigger an increase in intracellular Ca2+ concentration, which is closely linked with ferroptosis, and participate in decreased oxygen consumption by inhibiting HIF-1α in tumor cells, potentiating PDT antitumor efficiency. Thus, CAP and the photosensitizer IR780 are coencapsulated into highly biocompatible human serum albumin (HSA) to construct a nanoplatform (CI@HSA NPs) for synergistic tumor treatment under near-infrared (NIR) irradiation. Furthermore, the potential underlying signaling pathways of the combination therapy are investigated. CI@HSA NPs achieve real-time dynamic distribution monitoring and exhibit excellent antitumor efficacy with superior biosafety in vivo. Overall, this work highlights a promising NIR imaging-guided "pro-death" strategy to overcome the limitations of PDT for OS by promoting ferroptosis and alleviating hypoxia, providing inspiration and support for future innovative tumor therapy approaches.

Novel dual-target FAAH and TRPV1 ligands as potential pharmacotherapeutics for pain management

Dual-acting drugs that simultaneously inhibit fatty acid amide hydrolase (FAAH) and antagonize the transient receptor potential vanilloid 1 (TRPV1) is a promising stronger therapeutic approach for pain management without side effects associated with single-target agents. Here, several series of dual FAAH/TRPV1 blockers were designed and synthesized through rational molecular hybridization between the pharmacophore of classical TRPV1 antagonists and FAAH inhibitors. The studies resulted in compound 2r, which exhibited strong dual FAAH/TRPV1 inhibition/antagonism in vitro, exerted powerful analgesic effects in formalin-induced pain test (phase II, in mice), desirable anti-inflammatory activity in carrageenan-induced paw edema in rats, no TRPV1-related hyperthermia side effect, and favorable pharmacokinetic properties. Meanwhile, the contributions of TRPV1 and FAAH to its antinociceptive effects were verified by target engagement and molecular docking studies. Overall, compound 2r can serve as a new scaffold for developing FAAH/TRPV1 dual-activie ligands to counteract pain.

A journey from molecule to physiology and in silico tools for drug discovery targeting the transient receptor potential vanilloid type 1 (TRPV1) channel

The heat and capsaicin receptor TRPV1 channel is widely expressed in nerve terminals of dorsal root ganglia (DRGs) and trigeminal ganglia innervating the body and face, respectively, as well as in other tissues and organs including central nervous system. The TRPV1 channel is a versatile receptor that detects harmful heat, pain, and various internal and external ligands. Hence, it operates as a polymodal sensory channel. Many pathological conditions including neuroinflammation, cancer, psychiatric disorders, and pathological pain, are linked to the abnormal functioning of the TRPV1 in peripheral tissues. Intense biomedical research is underway to discover compounds that can modulate the channel and provide pain relief. The molecular mechanisms underlying temperature sensing remain largely unknown, although they are closely linked to pain transduction. Prolonged exposure to capsaicin generates analgesia, hence numerous capsaicin analogs have been developed to discover efficient analgesics for pain relief. The emergence of in silico tools offered significant techniques for molecular modeling and machine learning algorithms to indentify druggable sites in the channel and for repositioning of current drugs aimed at TRPV1. Here we recapitulate the physiological and pathophysiological functions of the TRPV1 channel, including structural models obtained through cryo-EM, pharmacological compounds tested on TRPV1, and the in silico tools for drug discovery and repositioning.

Progress in the development of TRPV1 small-molecule antagonists: Novel Strategies for pain management

Transient receptor potential vanilloid 1 (TRPV1) channels are widely distributed in sensory nerve endings, the central nervous system, and other tissues, functioning as ion channel proteins responsive to thermal pain and chemical stimuli. In recent years, the TRPV1 receptor has garnered significant interest as a potential therapeutic approach for various pain-related disorders, particularly TRPV1 antagonists. The present review offers a comprehensive, systematic exploration of both first- and second-generation TRPV1 antagonists in the context of pain management. Antagonists are categorized and explicated according to their structural characteristics. Detailed examination of binding modes, structural features, and pharmacological activities, alongside a critical appraisal of the advantages and limitations inherent to typical compounds within each structural category, are undertaken. Detailed discussions of the binding modes, structural features, pharmacological activities, advantages, and limitations of typical compounds within each structural category offer valuable insights and guidance for the future research and development of safer, more effective, and more targeted TRPV1 antagonists.

Calcitonin gene-related peptide ameliorates sepsis-induced intestinal injury by suppressing NLRP3 inflammasome activation

Intestinal damage has long been viewed as the primary cause of sepsis-induced multiple organ dysfunction syndrome (MODS). Previous studies have demonstrated that calcitonin gene-related peptide (CGRP) exhibits anti-inflammatory and protective effects in mice exposed to endotoxin. This study investigated whether CGRP protects against sepsis-induced intestinal damage and its underlying mechanisms. Using a murine caecal ligation and puncture (CLP) model, we observed elevated serum and intestinal CGRP levels in septic mice. CGRP knockout (KO) mice showed more severe intestinal barrier damage, excessive NLRP3 inflammasome activation and higher levels of inflammation. In vitro, we used lipopolysaccharide (LPS) and adenosine triphosphate (ATP) to activate the NLRP3 inflammasome in MODE-K murine intestinal epithelial cells. CGRP inhibited NF-κB pathway activation; prevented ASC assembly and ROS accumulation; significantly decreased NLRP3, Caspase-1 p10, and IL-1β levels and LDH release; and increased cell viability. Treatment with an IL-1β inhibitor or CGRP suppressed p38 MAPK and ERK1/2 pathway activation and increased ZO-1 and Occludin protein levels in LPS+ATP-treated MODE-K cells. Finally, we used the CGRP upstream agonist drug rutaecarpine (RUT) to control endogenous CGRP release in mice, and this drug demonstrated good therapeutic effects on septic intestinal injury. In conclusion, our results suggest that CGRP ameliorates sepsis-induced intestinal damage, providing valuable insights for drug development.

Natural Active Ingredients and TRPV1 Modulation: Focus on Key Chemical Moieties Involved in Ligand-Target Interaction

Diseases such as cancer, neurological pathologies and chronic pain represent currently unmet needs. The existing pharmacotherapeutic options available for treating these conditions are limited by lack of efficiency and/or side effects. Transient receptor potential vanilloid 1 ion channel emerged as an attractive therapeutic target for developing new analgesic, anti-cancer and antiepileptic agents. Furthermore, various natural ingredients were shown to have affinity for this receptor. The aim of this narrative review was to summarize the diverse natural scaffolds of TRPV1 modulators based on their agonistic/antagonistic properties and to analyze the structure-activity relationships between the ligands and molecular targets based on the results of the existing molecular docking, mutagenesis and in vitro studies. We present here an exhaustive collection of TRPV1 modulators grouped by relevant chemical features: vanilloids, guaiacols, phenols, alkylbenzenes, monoterpenes, sesquiterpenoids, alkaloids, etc. The information herein is useful for understanding the key structural elements mediating the interaction with TRPV1 and how their structural variation impacts the interaction between the ligand and receptor. We hope this data will contribute to the design of novel effective and safe TRPV1 modulators, to help overcome the lack of effective therapeutic agents against pathologies with high morbidity and mortality.

Regulation of transient receptor potential channels by traditional Chinese medicines and their active ingredients

In recent years, activation of thermal transient receptor potential (TRP) ion channels at a range of temperatures has received widespread attention as a target for traditional Chinese medicine (TCM) to regulate body temperature and relieve pain. Discovery of transient receptor potential vanilloid 1 (TRPV1) was awarded a Nobel Prize, reflecting the importance of these channels. Here, the regulatory effects of TCMs and their active ingredients on TRP ion channels are reviewed, and future directions for research on the cold, hot, warm, cool, and neutral natures of TCMs are considered. In herbs with cold, hot, warm, cool, and neutral natures, we found 29 TCMs with regulatory effects on TRP ion channels, including Cinnamomi Cortex, Capsici Fructus, Rhei Radix et Rhizoma, Macleayae cordatae Herba, Menthae Haplocalycis Herba, and Rhodiolae Crenulatae Radix et Rhizoma. Although some progress has been made in understanding the regulation of TRP ion channels by TCMs and their ingredients, the molecular mechanism by which TCMs have this effect remains to be further studied. We hope this review will provide a reference for further research on the cold, hot, warm, cool, and neutral natures of TCMs.

Chemical Investigation of Tetradium ruticarpum Fruits and Their Antibacterial Activity against Helicobacter pylori

The fruit of Tetradium ruticarpum, known as Evodiae Fructus, is a traditional herbal medicine used to treat gastric and duodenal ulcers, vomiting, and diarrhea. The traditional usage can be potentially associated with the antibacterial activity of T. ruticarpum fruits against Helicobacter pylori. However, so far, the antibacterial activity of T. ruticarpum fruits and antibacterial components against H. pylori has not been investigated despite the traditional folk use. The current study was conducted to investigate the bioactive chemical components of T. ruticarpum fruits and evaluate their antibacterial activity against H. pylori. Phytochemical investigation of the EtOH extract of T. ruticarpum fruits led to the isolation and identification of nine compounds (1-9), including phellolactone (1), the absolute configuration of which has not yet been determined. The chemical structures of the isolated compounds were elucidated by analyzing the spectroscopic data from one-dimensional (1D) and two-dimensional (2D) NMR and high-resolution electrospray ionization mass spectrometry (HR-ESIMS) experiments. Specifically, the absolute configuration of compound 1 was established by the application of computational methods, including electronic circular dichroism (ECD) calculation and the NOE/ROE-based interproton distance measurement technique via peak amplitude normalization for the improved cross-relaxation (PANIC) method. In the anti-H. pylori activity test, compound 3 showed the most potent antibacterial activity against H. pylori strain 51, with 94.4% inhibition (MIC₅₀ and MIC₉₀ values of 22 and 50 μM, respectively), comparable to that of metronidazole (97.0% inhibition, and MIC₅₀ and MIC₉₀ values of 17 and 46 μM, respectively). Moreover, compound 5 exhibited moderate antibacterial activity against H. pylori strain 51, with 58.6% inhibition (MIC₅₀ value of 99 μM), which was higher than that of quercetin (34.4% inhibition) as a positive control. Based on the bioactivity results, we also analyzed the structure-activity relationship of the anti-H. pylori activity. Conclusion: These findings demonstrated that T. ruticarpum fruits had antibacterial activity against H. pylori and could be used in the treatment of gastric and duodenal ulcers. Meanwhile, the active compound, 1-methyl-2-(8E)-8-tridecenyl-4(1H)-quinolinone (3), identified herein also indicated the potential application in the development of novel antibiotics against H. pylori.

Research Advances in Antitumor Mechanism of Evodiamine

Evodiamine is a natural alkaloid extracted from Fructus Evodia. This bioactive alkaloid has been reported to have a wide range of biological activities, including anti-injury, antiobesity, vasodilator, and anti-inflammatory effects. In recent years, it has been found that evodiamine has tumor-suppressive effects on a variety of tumors. There is growing evidence that evodiamine can inhibit the rapid proliferation of tumor cells, induce cell cycle arrest at a certain phase, increase the incidence of apoptosis, promote autophagy, inhibit microangiogenesis and migration, and regulate immunotherapy. Evodiamine can inhibit Wnt/β-catenin, mTOR, NF-κB, PI3K/AKT, JAK-STAT, and other signaling pathways in various cancer cells, and it can significantly downregulate the expression of many tumor markers, such as VEGF and COX-2. These facts partially explain the antitumor mechanism of evodiamine. In this article, the antitumor mechanism of evodiamine was reviewed to provide the basis for its clinical application and therapeutic development in the future.

Rutaecarpine Prevents High Glucose-Induced Endothelial Cell Senescence Through Transient Receptor Potential Vanilloid Subtype 1/ SIRT1 Pathway

ABSTRACT

SIRT1 functions as a longevity factor to counteract vascular aging induced by high glucose. Our previous study revealed that rutaecarpine, the natural agonist of transient receptor potential vanilloid subtype 1 (TRPV1), prevented high glucose-induced endothelial dysfunction. The present study aims to evaluate the effects of rutaecarpine on endothelial cell senescence induced by high glucose, and focus on the regulatory effect on SIRT1 expression. In cultured human umbilical vein endothelial cell (HUVEC), exposure to 33 mM high glucose for 72 hours induced cellular senescence, demonstrated as cell cycle arrest at G0/G1 phase, decreased cell viability, and increased number of senescence-associated β-galactosidase positive senescence cells and ROS production, which were effectively attenuated by treatment with rutaecarpine (0.3, 1, and 3 μM). Furthermore, rutaecarpine upregulated longevity protein SIRT1 expression in HUVECs, accompanied by decreased level of senescence marker p21. In addition, rutaecarpine increased intracellular calcium level in HUVECs, and pretreatment with TRPV1 antagonist capsazepine, intracellular Ca2+ chelator BAPTA-AM or CaM antagonist W-7 abolished the effects of rutaecarpine on SIRT1 expression. In summary, this study shows that rutaecarpine upregulates SIRT1 expression and prevents high glucose-induced endothelial cell senescence, which is related to activation of TRPV1/[Ca2+]i/CaM signal pathway. Our findings provide evidence that rutaecarpine may be a promising candidate with a novel mechanism in prevention vascular aging in diabetes.

A review of synthetic bioactive tetrahydro-β-carbolines: A medicinal chemistry perspective

1, 2, 3, 4-Tetrahydro-β-carboline (THβC) scaffold is widespread in many natural products (NPs) and synthetic compounds which show a variety of pharmacological activities. In this article, we reviewed the design, structures and biological characteristics of reported synthetic THβC compounds, and structure and activity relationship (SAR) of them were also discussed. This work might provide a reference for subsequent drug development based on THβC.

Network pharmacology and pharmacokinetics integrated strategy to investigate the pharmacological mechanism of Xianglian pill on ulcerative colitis

BACKGROUND

Ulcerative colitis (UC) is a chronic inflammatory bowel disease with high morbidity, which leads to poor quality of life. The Xianglian pill (XLP) is a classical Chinese patent medicine and has been clinically proven to be an effective treatment for UC.

PURPOSE

The pharmacological mechanism of the key bioactive ingredients of XLP for the treatment of UC was investigated by a network pharmacology and pharmacokinetics integrated strategy.

STUDY DESIGN AND METHODS

Network pharmacology was used to analyze the treatment effect of nine quantified XLP ingredients on UC. Key pathways were enriched and analyzed by protein-protein interaction and Kyoto Encyclopedia of Genes and Genomes analyses. The effect of XLP on Th17 cell differentiation was validated using a mouse model of UC. The binding of nine compounds with JAk2, STAT3, HIF-1α, and HSP90AB1 was assessed using molecular docking. A simple and reliable ultra-high-performance liquid chromatography-tandem mass spectrometry method was developed for the simultaneous quantification of nine ingredients from XLP in plasma and applied to a pharmacokinetic study following oral administration.

RESULTS

Nine compounds of XLP, including coptisine, berberine, magnoflorine,berberrubine, jatrorrhizine, palmatine, evodiamine, rutaecarpine, and dehydrocostus lactone, were detected. Network pharmacology revealed 50 crossover genes between the nine compoundsand UC. XLP treats UC mainly by regulating key pathways of the immune system, including Th17 cell differentiation, Jak-Stat, and PI3K-Akt signaling pathways. An in vivo validation in mice found that XLP inhibits Th17 cell differentiation by suppressing the Jak2-Stat3 pathway, which alleviates mucosal inflammation in UC. Molecular docking confirmed that eight compounds are capable of binding with JAk2, HIF-1α, and HSP90AB1, further confirming the inhibitory effect of XLP on the Jak2-Stat3 pathway. Moreover, apharmacokinetic study revealed that the nine ingredients of XLP are exposed in the plasma and colon tissue, which demonstrates its pharmacological effect on UC.

CONCLUSION

This study evaluates the clinical treatment efficacy of XLP for UC. The network pharmacology and pharmacokinetics integrated strategy evaluation paradigm is efficient in discovering the key pharmacological mechanism of herbal formulae.

A Luminescence-Based Human TRPV1 Assay System for Quantifying Pungency in Spicy Foods

The quantitation of pungency is difficult to achieve using sensory tests because of persistence, accumulation, and desensitization to the perception of pungency. Transient receptor vanilloid 1 (TRPV1), which is a chemosensory receptor, plays a pivotal role in the perception of many pungent compounds, suggesting that the activity of this receptor might be useful as an index for pungency evaluation. Although Ca²⁺-sensitive fluorescence dyes are commonly used for measuring human TRPV1 (hTRPV1) activity, their application is limited, as foods often contain fluorescent substances that interfere with the fluorescent signals. This study aims to design a new pungency evaluation system using hTRPV1. Instead of employing a fluorescent probe as the Ca²⁺ indicator, this assay system uses the luminescent protein aequorin. The luminescence assay successfully evaluated the hTRPV1 activity in foods without purification, even for those containing fluorescent substances. The hTRPV1 activity in food samples correlated strongly with the pungency intensity obtained by the human sensory test. This luminescence-based hTRPV1 assay system will be a powerful tool for objectively quantifying the pungency of spicy foods in both laboratory and industrial settings.

Evodiamine: A review of its pharmacology, toxicity, pharmacokinetics and preparation researches

ETHNOPHARMACOLOGICAL RELEVANCE

Evodia rutaecarpa, a well-known herb medicine in China, is extensively applied in traditional Chinese medicine (TCM). The plant has the effects of dispersing cold and relieving pain, arresting vomiting, and helping Yang and stopping diarrhea. Modern research demonstrates that evodiamine, the main component of Evodia rutaecarpa, is the material basis for its efficacy.

AIMS OF THE REVIEW

This paper is primarily addressed to summarize the current studies on evodiamine. The progress in research on the pharmacology, toxicology, pharmacokinetics, preparation researches and clinical application are reviewed. Moreover, outlooks and directions for possible future studies concerning it are also discussed.

MATERIALS AND METHODS

The information of this systematic review was conducted with resources of multiple literature databases including PubMed, Google scholar, Web of Science and Wiley Online Library and so on, with employing a combination of keywords including "pharmacology", "toxicology", "pharmacokinetics" and "clinical application", etc. RESULTS: As the main component of Evodia rutaecarpa, evodiamine shows considerable pharmacological activities, such as analgesic, anti-inflammatory, anti-tumor, anti-microbial, heart protection and metabolic disease regulation. However, it is also found that it has significant hepatotoxicity and cardiotoxicity, thereby it should be monitored in clinical. In addition, available data demonstrate that the evodiamine has a needy solubility in aqueous medium. Scientific and reasonable pharmaceutical strategies should be introduced to improve the above defects. Meanwhile, more efforts should be made to develop novel efficient and low toxic derivatives.

CONCLUSIONS

This review summarizes the results from current studies of evodiamine, which is one of the valuable medicinal ingredients from Evodia rutaecarpa. With the assistance of relevant pharmacological investigation, some conventional application and problems in pharmaceutical field have been researched in recent years. In addition, unresolved issues include toxic mechanisms, pharmacokinetics, novel pharmaceutical researches and relationship between residues and intestinal environment, which are still being explored and excavate before achieving integration into clinical practice.

Evodiamine reduced peripheral hypersensitivity on the mouse with nerve injury or inflammation

Management of chronic pain is still hard, and new analgesic drugs are needed. Evodiamine (Evo) and rutaecarpine (Rut) are two major active components of Evodia rutaecarpa, a Chinese traditional medicine that has been used as an analgesic for a long time. However, their effects on peripheral hypersensitivity remain unknown. Similar to capsaicin, the Evo and Rut were docked to the transient receptor potential cation channel subfamily V member 1 (TRPV1) in molecular simulation experiments. Moreover, Evo (10 µM) and Rut (50 µM) activated TRPV1 on human embryonic kidney 293 (HEK293) cells in electrophysiological recording experiments. Behaviorally, the application of Evo and Rut reduced peripheral hypersensitivity in a dose-dependent manner, which was blocked by capsazepine (a selective inhibitor of TRPV1). Furthermore, both Evo and Rut increased time in the open arms of the elevated plus maze on mice with nerve injury. These observations suggested that Evo and Rut reduced peripheral hypersensitivity and anxiety in mice with nerve injury or inflammation via TRPV1.

Vitamin D is an endogenous partial agonist of the transient receptor potential vanilloid 1 channel

KEY POINTS

25-Hydroxyvitamin D (25OHD) is a partial agonist of TRPV1 whereby 25OHD can weakly activate TRPV1 yet antagonize the stimulatory effects of the full TRPV1 agonists capsaicin and oleoyl dopamine. 25OHD binds to TRPV1 within the same vanilloid binding pocket as capsaicin. 25OHD inhibits the potentiating effects of PKC-mediated TRPV1 activity. 25OHD reduces T-cell activation and trigeminal neuron calcium signalling mediated by TRPV1 activity. These results provide evidence that TRPV1 is a novel receptor for the biological actions of vitamin D in addition to the well-documented effects of vitamin D upon the nuclear vitamin D receptor. The results may have important implications for our current understanding of certain diseases where TRPV1 and vitamin D deficiency have been implicated, such as chronic pain and autoimmune diseases, such as type 1 diabetes.

ABSTRACT

The capsaicin receptor TRPV1 plays an important role in nociception, inflammation and immunity and its activity is regulated by exogenous and endogenous lipophilic ligands. As vitamin D is lipophilic and involved in similar biological processes as TRPV1, we hypothesized that it directly regulates TRPV1 activity and function. Our calcium imaging and electrophysiological data demonstrate that vitamin D (25-hydroxyvitamin D (25OHD) and 1,25-hydroxyvitamin D (1,25OHD)) can weakly activate TRPV1 at physiologically relevant concentrations (100 nM). Furthermore, both 25OHD and 1,25OHD can inhibit capsaicin-induced TRPV1 activity (IC50  = 34.3 ± 0.2 and 11.5 ± 0.9 nM, respectively), but not pH-induced TRPV1 activity, suggesting that vitamin D interacts with TRPV1 in the same region as the TRPV1 agonist capsaicin. This hypothesis is supported by our in silico TRPV1 structural modelling studies, which place 25OHD in the same binding region as capsaicin. 25OHD also attenuates PKC-dependent TRPV1 potentiation via interactions with a known PKC phospho-acceptor residue in TRPV1. To provide evidence for a physiological role for the interaction of vitamin D with TRPV1, we employed two different cellular models known to express TRPV1: mouse CD4+ T-cells and trigeminal neurons. Our results indicate that 25OHD reduces TRPV1-induced cytokine release from T-cells and capsaicin-induced calcium activity in trigeminal neurons. In summary, we provide evidence that vitamin D is a novel endogenous regulator of TRPV1 channel activity that may play an important physiological role in addition to its known effects through the canonical nuclear vitamin D receptor pathway.

The Role of Traditional Chinese Herbal Medicines and Bioactive Ingredients on Ion Channels: A Brief Review and Prospect

Traditional Chinese Medicines (TCMs), particularly the Chinese herbal medicines, are valuable sources of medicines and have been used for centuries. The term "TCMs" both represents to the single drug agent like Salvia miltiorrhiza, Ligusticum chuanxiong and Angelica sinensis, and those herbal formulas like Jingshu Keli, Wenxin Keli and Danzhen powder. In recent years, the researches of TCMs developed rapidly to understand the scientific basis of these herbs. In this review, we collect the studies of TCM and their containing bioactive compounds, and attempt to provide an overview for their regulatory effects on different ion channels including Ca2+, K+, Na+, Cl- channels and TRP, P2X receptors. The following conditions are used to limit the range of our review. (i) Only the herbal materials are included in this review and the animal- and mineral-original TCMs are excluded. (ii) The major discussions in this review focus on single TCM agent and the herbal formulas are only discussed for a little. (iii) Those most famous herbal medicines like Capsicum annuum (pepper), Curcuma longa (ginger) and Cannabis sativa (marijuana) are excluded. (iv) Only those TCM herbs with more than 5 research papers confirming their effects on ion channels are discussed in this review. Our review discusses recently available scientific evidences for TCMs and related bioactive compounds that have been reported with the modulatory effects on different ion channels, and thus provides a new ethnopharmacological approach to understand the usage of TCMs.

Evodiamine and rutaecarpine from Tetradium ruticarpum in the treatment of liver diseases

BACKGROUND

Liver is the pivotal organ responsible for plasma protein production, biliary secretion, xenobiotic elimination, glucose and lipid homeostasis. Dysregulation of these functions usually leads to liver diseases and further related complications. The incidence of liver diseases is increasing worldwide, with high morbidity and mortality when at advanced stages, and has become significant public health concern and substential economic burden. Thus, novel therapeutic strategies for managing liver diseases progression are urgently required. T. ruticarpum is one of the most famous and frequently used herbal medicine and has been prescribed in traditional Chinese medicine (TCM) formulas for the treatment of various ailments, including liver diseases. A considerable amount of bioactive ingredients have been isolated and identified from the roots of T. ruticarpum, including alkaloids, saponins, phenols, volatile oils and other compounds. Among these compounds, evodiamine (EVO) and rutaecarpine (RUT) are believed to be the most bioactive compounds.

PURPOSE

To summarize recent findings regarding to the metabolism, pharmacological/toxicological effects of EVO and RUT and to highlight the potential therapeutic effects of them against liver diseases.

METHODS

Online academic databases (including PubMed, Google Scholar, Web of Science and CNKI) were searched using search terms of "T. ruticarpum", "Wu Zhu Yu", "evodiamine", "rutaecarpine", "liver" and combinations to include published studies of EVO and RUT primarily from 2004-2019. Several critical previous studies beyond this period were also included.

RESULTS

Evodiamine (EVO) and rutaecarpine (RUT) are believed to be the most bioactive alkaloids in T. ruticarpum, having anti-inflammation, anti-fibrosis, anti-lipotoxicity, anti-cancer activities, and thus having potential to improve liver disorders. In the current review, we comprehensively summarized recent progresses in the studies of EVO- and RUT-mediated promising hepatoprotective effects and also provide novel insights regarding the potential use of EVO and RUT as therapeutic options for the treatment of liver diseases.

CONCLUSION

With further in-depth pharmacology and pharmacokinetic studies, we believe that natural products in T. ruticarpum and their derivatives will become promising medicines with improved clinical efficacy for the treatment of liver diseases in the immediate future.

TRP Channels in the Focus of Trigeminal Nociceptor Sensitization Contributing to Primary Headaches

Pain in trigeminal areas is driven by nociceptive trigeminal afferents. Transduction molecules, among them the nonspecific cation channels transient receptor potential vanilloid 1 (TRPV1) and ankyrin 1 (TRPA1), which are activated by endogenous and exogenous ligands, are expressed by a significant population of trigeminal nociceptors innervating meningeal tissues. Many of these nociceptors also contain vasoactive neuropeptides such as calcitonin gene-related peptide (CGRP) and substance P. Release of neuropeptides and other functional properties are frequently examined using the cell bodies of trigeminal neurons as models of their sensory endings. Pathophysiological conditions cause phosphorylation, increased expression and trafficking of transient receptor potential (TRP) channels, neuropeptides and other mediators, which accelerate activation of nociceptive pathways. Since nociceptor activation may be a significant pathophysiological mechanism involved in both peripheral and central sensitization of the trigeminal nociceptive pathway, its contribution to the pathophysiology of primary headaches is more than likely. Metabolic disorders and medication-induced painful states are frequently associated with TRP receptor activation and may increase the risk for primary headaches.

Design, synthesis and biological evaluation of novel 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole triazole derivatives as potent TRPV1 antagonists

Reported herein is the design, synthesis, and pharmacologic evaluation of a class of TRPV1 antagonists constructed on 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole as A-region and triazole as B-region. The SAR analysis indicated that 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole analogues displayed excellent antagonism of hTRPV1 activation by capsaicin and showed better potency compared to the corresponding dihydroindole analogues. Optimization of this design led to the eventual identification of 2-((1-(2-(trifluoromethyl)phenyl)-1H-1,2,3-triazol-4-yl)methyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (6g), a potent TRPV1 antagonist. In vitro, using cells expressing recombinant human TRPV1 channels, 6g displayed potent antagonism activated by capsaicin (IC₅₀ = 0.075 μM) and only partially blocked acid activation of TRPV1. In vivo, 6g exhibited good efficacy in capsaicin-induced and heat-induced pain models and had almost no hyperthermia side-effect. Furthermore, pharmacokinetic studies revealed that compound 6g had a superior oral exposure after oral administration in rats. To understand its binding interactions with the receptor, the docking study of 6g was performed in rTRPV1 model and showed an excellent fit to the binding site. On the basis of its superior profiles, 6g could be considered as the lead candidate for the further development of antinociceptive drugs.

A concise synthesis and biological study of evodiamine and its analogues

Efficient access to evodiamine and its analogues is presented via Lewis acid catalysis. In this reaction, three chemical bonds and two heterocyclic-fused rings are constructed in one step.

Anticancer Activity of Natural and Synthetic Capsaicin Analogs

The nutritional compound capsaicin is the major spicy ingredient of chili peppers. Although traditionally associated with analgesic activity, recent studies have shown that capsaicin has profound antineoplastic effects in several types of human cancers. However, the applications of capsaicin as a clinically viable drug are limited by its unpleasant side effects, such as gastric irritation, stomach cramps, and burning sensation. This has led to extensive research focused on the identification and rational design of second-generation capsaicin analogs, which possess greater bioactivity than capsaicin. A majority of these natural capsaicinoids and synthetic capsaicin analogs have been studied for their pain-relieving activity. Only a few of these capsaicin analogs have been investigated for their anticancer activity in cell culture and animal models. The present review summarizes the current knowledge of the growth-inhibitory activity of natural capsaicinoids and synthetic capsaicin analogs. Future studies that examine the anticancer activity of a greater number of capsaicin analogs represent novel strategies in the treatment of human cancers.

Biologically active quinoline and quinazoline alkaloids part II

To follow-up on our prior Part I review, this Part II review summarizes and provides updated literature on novel quinoline and quinazoline alkaloids isolated during the period of 2009-2016, together with the biological activity and the mechanisms of action of these classes of natural products. Over 200 molecules with a broad range of biological activities, including antitumor, antiparasitic and insecticidal, antibacterial and antifungal, cardioprotective, antiviral, anti-inflammatory, hepatoprotective, antioxidant, anti-asthma, antitussive, and other activities, are discussed. This survey should provide new clues or possibilities for the discovery of new and better drugs from the original naturally occurring quinoline and quinazoline alkaloids.

Copper-catalyzed C–O bond cleavage and cyclization: synthesis of indazolo[3,2-b]quinazolinones

Cu-catalyzed sequential inert C–O bond cleavage followed by intramolecular C–N bond formation for the synthesis of indazolo[3,2-b]quinazolinones.