Imperatorin inhibits HIV-1 replication through an Sp1-dependent pathway

Inhibitory effect of imperatorin on dabrafenib metabolism in vitro and in vivo

Dabrafenib is a BRAF inhibitor that has been demonstrated to be efficacious in the treatment of melanoma and non-small-cell lung cancer patients with BRAF V600E mutations. The objective of this study was to investigate the effects of 51 traditional Chinese medicines on the metabolism of dabrafenib and to further investigate the inhibitory effect of imperatorin. The quantification of dabrafenib and its metabolite hydroxy-dabrafenib was carried out using a sensitive, rapid, and accurate assay method based on ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The results of in vitro experiments showed that 20 drugs inhibited the metabolism of dabrafenib by more than 80 %. In a further study of imperatorin on dabrafenib, the half-maximal inhibitory concentration (IC50) values of imperatorin on dabrafenib were 0.22 μM and 3.68 μM in rat liver microsomes (RLM) and human liver microsomes (HLM), respectively, while the inhibition mechanisms were non-competitive and mixed type inhibition, respectively. The results of in vivo experiments demonstrated that in the presence of imperatorin, the AUC(0-t), AUC(0-∞), Cmax, and Tmax of dabrafenib were increased by 2.38-, 2.26-, 1.05-, and 6.10-fold, respectively, while CLz/F was decreased by 67.9 %. In addition, Tmax of hydroxy-dabrafenib was increased by 1.4-fold. The results of the research showed that imperatorin had a consistent inhibitory effect on dabrafenib in vitro and in vivo. When the concurrent use of dabrafenib and imperatorin is unavoidable, clinicians should closely monitor for potential adverse events and make timely adjustments to the administered dosage.

Natural linear coumarin-heterocyclic conjugates: A review of their roles in phytotherapy

Heterocycle conjugates provide a fresh investigative scope to find novel molecules with enhanced phytotherapeutic characteristics. Coumarin-based products are widely used in the synthesis of several compounds with biological and medicinal properties since they are naturally occurring heterocycles with a broad dispersion. The investigation of coumarin-based phytochemicals with annulated heterocyclic rings is a promising approach to discovering novel conjugates with significant phytotherapeutic attributes. Due to the applicable coumarin extraction processes, a range of linear coumarin-heterocyclic conjugates were isolated from different natural resources and exhibited remarkable therapeutic efficacy. This review highlights the phytotherapeutic potential and origins of various natural linear coumarin-heterocyclic conjugates. We searched several databases, including Science Direct, Web of Science, Springer, Google Scholar, and PubMed. After sieving, we ultimately identified and included 118 pertinent studies published between 2000 and the middle of 2023. This will inspire medicinal chemists with extremely insightful ideas for designing and synthesizing therapeutically active lead compounds in the future that are built on the pharmacophores of coumarin-heterocyclic conjugates and have significant therapeutic attributes.

The Different Composition of Coumarins and Antibacterial Activity of Phlojodicarpus sibiricus and Phlojodicarpus villosus Root Extracts

Phlojodicarpus sibiricus, a valuable endangered medicinal plant, is a source of angular pyranocoumarins used in pharmacology. Due to limited resource availability, other pyranocoumarin sources are needed. In the present research, the chemical composition of a closely related species, Phlojodicarpus villosus, was studied, along with P. sibiricus. High-performance liquid chromatography and mass-spectrometric analyses, followed by antibacterial activity studies of root extracts from both species, were performed. P. sibiricus and P. villosus differed significantly in coumarin composition. Pyranocoumarins predominated in P. sibiricus, while furanocoumarins predominated in P. villosus. Osthenol, the precursor of angular pyrano- and furanocoumarins, was detected in both P. sibiricus and P. villosus. Angular forms of coumarins were detected in both species according to the mass-spectrometric behavior of the reference. Thus, P. villosus cannot be an additional source of pyranocoumarins because their content in the plant is critically low. At the same time, the plant contained large amounts of hydroxycoumarins and furanocoumarins. The extracts exhibited moderate antibacterial activity against five standard strains. The P. villosus extract additionally suppressed the growth of the Gram-negative bacterium E. coli. Thus, both Phlojodicarpus species are promising for further investigation in the field of pharmaceuticals as producers of different coumarins.

Overexpression of Alpha-1 Antitrypsin Increases the Proliferation of Mesenchymal Stem Cells by Upregulation of Cyclin D1

Alpha-1 antitrypsin-overexpressing mesenchymal stromal/stem cells (AAT-MSCs) showed improved innate properties with a faster proliferation rate when studied for their protective effects in mouse models of diseases. Here, we investigated the potential mechanism(s) by which AAT gene insertion increases MSC proliferation. Human bone marrow-derived primary or immortalized MSCs (iMSCs) or AAT-MSCs (iAAT-MSCs) were used in the study. Cell proliferation was measured by cell counting and cell cycle analysis. Possible pathways involved in the pro-proliferation effect of AAT were investigated by measuring mRNA and protein expression of key cell cycle genes. Interval cell counting showed increased proliferation in AAT-MSCs or iAAT-MSCs compared to their corresponding MSC controls. Cell cycle analysis revealed more cells progressing into the S and G2/M phases in iAAT-MSCs, with a notable increase in the cell cycle protein, Cyclin D1. Moreover, treatment with Cyclin D1 inhibitors showed that the increase in proliferation is due to Cyclin D1 and that the AAT protein is upstream and a positive regulator of Cyclin D1. Furthermore, AAT's effect on Cyclin D1 is independent of the Wnt signaling pathway as there were no differences in the expression of regulatory proteins, including GSK3β and β-Catenin in iMSC and iAAT-MSCs. In summary, our results indicate that AAT gene insertion in an immortalized MSC cell line increases cell proliferation and growth by increasing Cyclin D1 expression and consequently causing cells to progress through the cell cycle at a significantly faster rate.

Bioactivity and toxicity of coumarins from African medicinal plants

Introduction: Coumarins are naturally occuring metabolites from plants and a few micro-organisms. They have been widely used in the food and drug industry in their natural or synthetic forms. Numerous coumarins possess several biological activities such as anti-inflammatory, anti-ulcers, anti-tumour, anti-microbial, anti-coagulant. The aim of this study was to assess the bioactivity, and toxicity of coumarins from African medicinal plants. Methods: We searched online databases and search engines such as PubMed, Google Scholar and Web of Science for key terms such as coumarins, toxicity, bioavailability, bioactivity with appropriate Boolean operators. Only full-length research articles published in English between 1956 to 2023 were reviewed. Results: We recorded 22 coumarins from 15 plant species from Africa. Most of the plant species (33%) were from North Africa. These were followed by East Africa at 21%, then West, and Central Africa at 18.2% each. Most of the coumarins (21.3%) were isolated from the entire plant and the leaves (19.1%) and most of them (46.7%) had some antimicrobial activity. Five coumarins viz osthole, pseudocordatolide C & calanolide, chartreusin and esculetin had either antitumor or anticancer activity. Six coumarins had varying levels and types of toxicity ranging from inhibiting blood clotting as anticoagulants, to cytotoxic effects, causing hyperventilation, tremor, & photophobia, pulmonary haemorrhage, carcinogenic activity, severe neurotoxicity, hepato- and phototoxicity. Conclusion: Several African medicinal plants are sources of various coumarins that possess several biological activities as well as toxicities. This calls for more research into their safety and efficacy because of their wide spread applications as therapeutic agents.

Imperatorin Restores Chemosensitivity of Multidrug-Resistant Cancer Cells by Antagonizing ABCG2-Mediated Drug Transport

The high expression of the ATP-binding cassette (ABC) drug transporter ABCG2 in cancer cells contributes to the emergence of multidrug resistance (MDR) in individuals afflicted with either solid tumors or blood cancers. MDR poses a major impediment in the realm of clinical cancer chemotherapy. Recently, substantial endeavors have been dedicated to identifying bioactive compounds isolated from nature capable of counteracting ABCG2-mediated MDR in cancer cells. Imperatorin, a natural coumarin derivative renowned for its diverse pharmacological properties, has not previously been explored for its impact on cancer drug resistance. This study investigates the chemosensitizing potential of imperatorin in ABCG2-overexpressing cancer cells. Experimental results reveal that at sub-toxic concentrations, imperatorin significantly antagonizes the activity of ABCG2 and reverses ABCG2-mediated MDR in a concentration-dependent manner. Furthermore, biochemical data and in silico analysis of imperatorin docking to the inward-open conformation of human ABCG2 indicate that imperatorin directly interacts with multiple residues situated within the transmembrane substrate-binding pocket of ABCG2. Taken together, these results furnish substantiation that imperatorin holds promise for further evaluation as a potent inhibitor of ABCG2, warranting exploration in combination drug therapy to enhance the effectiveness of therapeutic agents for patients afflicted with tumors that exhibit high levels of ABCG2.

Overexpression of Alpha-1 Antitrypsin Increases the Proliferation of Mesenchymal Stem Cells by Upregulation of Cyclin D1 and is Independent of the Wnt Signaling Pathway

Alaph-1 antitrypsin overexpressing mesenchymal stromal/stem cells (AAT-MSCs) showed improved innate properties with a faster proliferation rate when studied for their protective effects in mouse models of diseases. Here, we investigated the potential mechanism(s) by which AAT gene insertion increases MSC proliferation. Human bone marrow-derived primary or immortalized MSCs (iMSCs) or AAT-MSCs (iAAT-MSCs) were used in the study. Cell proliferation was measured by cell counting and cell cycle analysis. Possible pathways involved in the pro-proliferation effect of AAT were investigated by measuring mRNA and protein expression of key cell cycle genes. Interval cell counting showed increased proliferation in AAT-MSCs or iAAT-MSCs compared to their corresponding MSC controls. Cell cycle analysis revealed more cells progressing into the S and G2/M phases in iAAT-MSCs, with a notable increase in the cell cycle protein, Cyclin D1. Moreover, treatment with Cyclin D1 inhibitors showed that the increase in proliferation is due to Cyclin D1 and that the AAT protein is upstream and a positive regulator of Cyclin D1. Furthermore, AAT's effect on Cyclin D1 is independent of the Wnt signaling pathway as there were no differences in the expression of regulatory proteins, including GSK3β and β-Catenin in iMSC and iAAT-MSCs. In summary, our results indicate that AAT gene insertion in an immortalized MSC cell line increases cell proliferation and growth by increasing Cyclin D1 expression and consequently causing cells to progress through the cell cycle at a significantly faster rate.

A comprehensive overview on the role of phytocompounds in human immunodeficiency virus treatment

Acquired immune deficiency syndrome (AIDS) is a worldwide epidemic caused by human immunodeficiency virus (HIV) infection. Newer medicines for eliminating the viral reservoir and eradicating the virus are urgently needed. Attempts to locate relatively safe and non-toxic medications from natural resources are ongoing now. Natural-product-based antiviral candidates have been exploited to a limited extent. However, antiviral research is inadequate to counteract for the resistant patterns. Plant-derived bioactive compounds hold promise as powerful pharmacophore scaffolds, which have shown anti-HIV potential. This review focuses on a consideration of the virus, various possible HIV-controlling methods and the recent progress in alternative natural compounds with anti-HIV activity, with a particular emphasis on recent results from natural sources of anti-HIV agents. Please cite this article as: Mandhata CP, Sahoo CR, Padhy RN. A comprehensive overview on the role of phytocompounds in human immunodeficiency virus treatment. J Integr Med. 2023; Epub ahead of print.

Plant Coumarins with Anti-HIV Activity: Isolation and Mechanisms of Action

This review summarizes and systematizes the literature on the anti-HIV activity of plant coumarins with emphasis on isolation and the mechanism of their antiviral action. This review summarizes the information on the anti-HIV properties of simple coumarins as well as annulated furano- and pyranocoumarins and shows that coumarins of plant origin can act by several mechanisms: inhibition of HIV reverse transcriptase and integrase, inhibition of cellular factors that regulate HIV-1 replication, and transmission of viral particles from infected macrophages to healthy ones. It is important to note that some pyranocoumarins are able to act through several mechanisms or bind to several sites, which ensures the resistance of these compounds to HIV mutations. Here we review the last two decades of research on the anti-HIV activity of naturally occurring coumarins.

Imperatorin Positively Regulates Melanogenesis through Signaling Pathways Involving PKA/CREB, ERK, AKT, and GSK3β/β-Catenin

The present study investigated the melanogenic effects of imperatorin and isoimperatorin and the underlying mechanisms of imperatorin using a mouse melanoma B16F10 model. Interestingly, treatment with 25 μM of either imperatorin or isoimperatorin, despite their structural differences, did not produce differences in melanin content and intracellular tyrosinase activity. Imperatorin also activated the expression of melanogenic enzymes, such as tyrosinase (TYR) and tyrosinase-related proteins TYRP-1 and TYRP-2. Mechanistically, imperatorin increases melanin synthesis through the cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA)/cAMP-responsive element-binding protein (CREB)-dependent upregulation of microphthalmia-associated transcription factor (MITF), which is a key transcription factor in melanogenesis. Furthermore, imperatorin exerted melanogenic effects by downregulating extracellular signal-regulated kinase (ERK) and upregulating phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT)/glycogen synthesis kinase-3β (GSK-3β). Moreover, imperatorin increased the content of β-catenin in the cell cytoplasm and nucleus by reducing the content of phosphorylated β-catenin (p-β-catenin). Finally, we tested the potential of imperatorin in topical application through primary human skin irritation tests. These tests were performed on the normal skin (upper back) of 31 volunteers to determine whether 25 or 50 µM of imperatorin had irritation or sensitization potential. During these tests, imperatorin did not induce any adverse reactions. Taken together, these findings suggest that the regulation of melanogenesis by imperatorin can be mediated by signaling pathways involving PKA/CREB, ERK, AKT, and GSK3β/β-catenin and that imperatorin could prevent the pathogenesis of pigmentation diseases when used as a topical agent.

Simultaneous separation and determination of six furanocoumarins in Radix Angelicae dahuricae by CZE with dual CDs system

A novel, simple and efficient capillary electrophoresis method was developed to simultaneous determination of six furanocoumarins (psoralen, isopsoralen, imperatorin, isoimperatorin, phellopterin, and cnidilin). The separation buffer consisted of 30 mM boric acid, 12 mM sulfobutylether-β-cyclodextrin and 1.5 mM 2-hydroxypropyl-β-cyclodextrin (pH 7.8); the voltage was 20 kV, the temperature was 25 °C and the detection wavelength was at 246 nm with a diode array detector (DAD). Under the above conditions, the analytes could be separated with high resolution in less than 7 min. This method was used to simultaneously determine the content of psoralen, imperatorin, isoimperatorin and phellopterin in Angelica Dahurica Radix. And good linearities were obtained with correlation coefficients from 0.9992 to 0.9999. The limits of detection (LOD, S/N = 3) and the limits of quantitation (LOQ, S/N = 10) ranged from 0.6 to 3.0 μg/mL and from 2.1 to 9.9 μg/mL, respectively. The recoveries ranged between 98.8% and 101.8%. The results indicated the method can achieve baseline separation and quantitative analysis of furanocoumarins in Chinese herbal medicines and formulations.

The Angelica dahurica: A Review of Traditional Uses, Phytochemistry and Pharmacology

Angelica dahurica (A. dahurica) root is a famous edible medicinal herb that has been used in China for thousands of years. To date, more than 300 chemical constituents have been discovered from A. dahurica. Among these ingredients, coumarins and volatile oils are the major active compounds. Moreover, a few other compounds have also been isolated from the root of A. dahurica, such as alkaloids, phenols, sterols, benzofurans, polyacetylenes and polysaccharides. Modern pharmacological studies demonstrated that the root of A. dahurica and its active components displayed various bioactivities such as anti-inflammation, anti-tumor, anti-oxidation, analgesic activity, antiviral and anti-microbial effects, effects on the cardiovascular system, neuroprotective function, hepatoprotective activity, effects on skin diseases and so on. Based on these studies, this review focused on the research publications of A. dahurica and aimed to summarize the advances in the traditional uses, phytochemistry and pharmacology which will provide reference for the further studies and applications of A. dahurica.

Chemosensitizing effect and mechanism of imperatorin on the anti-tumor activity of doxorubicin in tumor cells and transplantation tumor model

Multidrug resistance of tumors has been a severe obstacle to the success of cancer chemotherapy. The study wants to investigate the reversal effects of imperatorin (IMP) on doxorubicin (DOX) resistance in K562/DOX leukemia cells, A2780/Taxol cells and in NOD/SCID mice, to explore the possible molecular mechanisms. K562/DOX and A2780/Taxol cells were treated with various concentrations of DOX and Taol with or without different concentrations of IMP, respectively. K562/DOX xenograft model was used to assess anti-tumor effect of IMP combined with DOX. MTT assay, Rhodamine 123 efflux assay, RT-PCR, and Western blot analysis were determined in vivo and in vitro. Results showed that IMP significantly enhanced the cytotoxicity of DOX and Taxol toward corresponding resistance cells. In vivo results illustrated both the tumor volume and tumor weight were significantly decreased after 2-week treatment with IMP combined with DOX compared to the DOX alone group. Western blotting and RT-PCR analyses indicated that IMP downregulated the expression of P-gp in K562/DOX xenograft tumors in NOD/SCID mice. We also evaluated glycolysis and glutamine metabolism in K562/DOX cells by measuring glucose consumption and lactate production. The results revealed that IMP could significantly reduce the glucose consumption and lactate production of K562/DOX cells. Furthermore, IMP could also remarkably repress the glutamine consumption, α-KG and ATP production of K562/DOX cells. Thus, IMP may sensitize K562/DOX cells to DOX and enhance the anti-tumor effect of DOX in K562/DOX xenograft tumors in NOD/SCID mice. IMP may be an adjuvant therapy to mitigate the multidrug resistance in leukemia chemotherapy.

Use of a Fission Yeast Platform to Identify and Characterize Small Molecule PDE Inhibitors

Cyclic nucleotide phosphodiesterases (PDEs) have been proven to be targets for which highly selective and potent drugs can be developed. Mammalian genomes possess 21 genes whose products are pharmacologically grouped into 11 families; however related genes from pathogenic organisms display sufficient divergence from the mammalian homologs such that PDE inhibitors to these enzymes could be used to treat parasitic infections without acting on the related human PDEs. We have developed a platform for expressing cloned PDEs in the fission yeast Schizosaccharomyces pombe, allowing for inexpensive, but robust screening for small molecule inhibitors that are cell permeable. Such compounds typically display the expected biological activity when tested in cell culture, including anti-inflammatory properties for PDE4 and PDE7 inhibitors. The genetic pliability of S. pombe also allows for molecular genetic screens to identify mutations in target PDE genes that confer some resistance to these inhibitors as a way of investigating the PDE-inhibitor interaction. This screening method is readily accessible to academic laboratories as it does not require the purification of large quantities of a target protein. This allows for the discovery and profiling of PDE inhibitors to treat inflammation or of inhibitors of targets such as pathogen PDEs for which there may not be a sufficient financial motivation for pharmaceutical companies to identify selective PDE inhibitors using more traditional in vitro enzyme-based screening methods.

Pharmacological perspectives and molecular mechanisms of coumarin derivatives against virus disease

Infections caused by viruses are one of the foremost causes of morbidity and mortality in the world. Although a number of antiviral drugs are currently used for treatment of various kinds of viral infection diseases, there is still no available therapeutic agent for most of the viruses in clinical practice. Coumarin is a chemical compound which is found naturally in a variety of plants, it can also be synthetically produced possessing diverse biological effects. More recently, reports have highlighted the potential role of coumarin derivatives as antiviral agents. This review outlines the advances in coumarin-based compounds against various viruses including human immunodeficiency virus, hepatitis virus, herpes simplex virus, Chikungunya virus and Enterovirus 71, as well as the structure activity relationship and the possible mechanism of action of the most potent coumarin derivatives.

Natural Coumarins: Exploring the Pharmacological Complexity and Underlying Molecular Mechanisms

Coumarins belong to the benzopyrone family commonly found in many medicinal plants. Natural coumarins demonstrated a wide spectrum of pharmacological activities, including anti-inflammatory, anticoagulant, anticancer, antibacterial, antimalarial, casein kinase-2 (CK2) inhibitory, antifungal, antiviral, Alzheimer's disease inhibition, neuroprotective, anticonvulsant, phytoalexins, ulcerogenic, and antihypertensive. There are very few studies on the bioavailability of coumarins; therefore, further investigations are necessitated to study the bioavailability of different coumarins which already showed good biological activities in previous studies. On the evidence of varied pharmacological properties, the present work presents an overall review of the derivation, availability, and biological capacities of coumarins with further consideration of the essential mode of their therapeutic actions. In conclusion, a wide variety of coumarins are available, and their pharmacological activities are of current interest thanks to their synthetic accessibility and riches in medicinal plants. Coumarins perform the valuable function as therapeutic agents in a range of medical fields.

Natural Products with Inhibitory Activity against Human Immunodeficiency Virus Type 1

Infections caused by human immunodeficiency virus (HIV) are considered one of the main public health problems worldwide. Antiretroviral therapy (ART) is the current modality of treatment for HIV-1 infection. It comprises the combined use of several drugs and can decrease the viral load and increase the CD4⁺ T cell count in patients with HIV-1 infection, thereby proving to be an effective modality. This therapy significantly decreases the rate of morbidity and mortality owing to acquired immunodeficiency syndrome (AIDS) and prolongs and improves the quality of life of infected patients. However, nonadherence to ART may increase viral resistance to antiretroviral drugs and transmission of drug-resistant strains of HIV. Therefore, it is necessary to continue research for compounds with anti-HIV-1 activity, exhibiting a potential for the development of an alternative or complementary therapy to ART with low cost and fewer side effects. Natural products and their derivatives represent an excellent option owing to their therapeutic potential against HIV. Currently, the derivatives of natural products available as anti-HIV-1 agents include zidovudine, an arabinonucleoside derivative of the Caribbean marine sponge (Tectitethya crypta), which inhibits the reverse transcriptase of the virus. This was the first antiviral agent approved for treatment of HIV infection. Additionally, bevirimat (isolated from Syzygium claviflorum) and calanolide A (isolated from Calophyllum sp.) are inhibitors of viral maturation and reverse transcription process, respectively. In the present review, we aimed to describe the wide repertoire of natural compounds exhibiting anti-HIV-1 activity that can be considered for designing new therapeutic strategies to curb the HIV pandemic.

Deverra tortuosa (Desf.) DC from Saudi Arabia as a new source of marmin and furanocoumarins derivatives with α-glucosidase, antibacterial and cytotoxic activities

Deverra tortuosa (Desf.) DC (Syn. Pituranthos tortusus (Desf.) Benth. & Hook.f.) is a species belonging to the Apiaceae family that is common in the Northern Region of Saudi Arabia. The plant is well known in traditional medicine along the Arabian ecoregion. In the framework of the present study, the crude extract of n-hexane and ethyl acetate of the seeds were fractionated to purify major bioactive secondary metabolites. Five compounds were identified for the first time from the seeds of D. tortuosa: Marmin 1, Pituranthoside 2, Isoimperatorin 3, Bergapten 4 and Isopimpinellin 5. Their structures were elucidated using 1D and 2D NMR, (ESI)-MS and IR spectroscopic analyses. The cytotoxic, α-glucosidase and antibacterial activities of the pure phytochemicals were also evaluated.

Small Molecule Inhibitors of White Spot Syndrome Virus: Promise in Shrimp Seedling Culture

Rapid production of prawn (Litopenaeus vannamei) under artificial pressure can result in a series of obvious challenges and is vulnerable to serious losses related to aquatic environmental issues and the unrestrained outbreak of white spot syndrome (WSS). However, to date, there are no therapeutic strategies to contain the spread of the virus. Here, we synthesized 27 coumarin derivatives and evaluated their anti-white spot syndrome virus (WSSV) activity in L. vannamei larvae. We demonstrated that electron-withdrawing and electron-giving substituent groups play an important role in reducing toxicity and WSSV replication, respectively. Two coumarin C2 (2-amino-5-oxo-4-(p-tolyl)-4H,5H-pyrano[3,2-c]chromene-3-carbonitrile) and C7 (2-amino-4-(4-chlorophenyl)-5-oxo-4H,5H-pyrano[3,2-c]chromene-3-carbonitrile) were regarded as the most promising anti-WSSV compounds with maximum antiviral response <5% and median effective concentration <10 mg/L. The mortality of WSSV-infected larvae decreased by more than 60% after exposure to C2 and C7. With continuous immersion of C2 and C7 exchange, the mortality further decreased to 40% at 120 h. Additionally, C2 and C7 are the relatively stable in aquacultural water, making these agents suitable for use in inhibiting WSSV horizontal transmission in static aquaculture systems. These results showed the marked advantages of using C2 and C7 in the shrimp industry, and suggest that they hold potential for the treatment and prevention of WSSV infection in shrimp seedling culture.

Balance between Retroviral Latency and Transcription: Based on HIV Model

The representative of the Lentivirus genus is the human immunodeficiency virus type 1 (HIV-1), the causative agent of acquired immunodeficiency syndrome (AIDS). To date, there is no cure for AIDS because of the existence of the HIV-1 reservoir. HIV-1 infection can persist for decades despite effective antiretroviral therapy (ART), due to the persistence of infectious latent viruses in long-lived resting memory CD4+ T cells, macrophages, monocytes, microglial cells, and other cell types. However, the biology of HIV-1 latency remains incompletely understood. Retroviral long terminal repeat region (LTR) plays an indispensable role in controlling viral gene expression. Regulation of the transcription initiation plays a crucial role in establishing and maintaining a retrovirus latency. Whether and how retroviruses establish latency and reactivate remains unclear. In this article, we describe what is known about the regulation of LTR-driven transcription in HIV-1, that is, the cis-elements present in the LTR, the role of LTR transcription factor binding sites in LTR-driven transcription, the role of HIV-1-encoded transactivator protein, hormonal effects on virus transcription, impact of LTR variability on transcription, and epigenetic control of retrovirus LTR. Finally, we focus on a novel clustered regularly interspaced short palindromic repeats-associated protein 9 (CRISPR/dCas9)-based strategy for HIV-1 reservoir purging.

Hydroxycoumarin efficiently inhibits spring viraemia of carp virus infection in vitro and in vivo

Spring viremia of carp virus (SVCV) causes devastating losses in aquaculture. Coumarin has an advantageous structure for the design of novel antiviral agents with high affinity and specificity. In this study, we evaluated a hydroxycoumarin medicine, i.e., 7-(6-benzimidazole) coumarin (C10), regarding its anti-SVCV effects in vitro and in vivo. Results showed that up to 12.5 mg/L C10 significantly inhibited SVCV replication in the epithelioma papulosum cyprini (EPC) cell line, with a maximum inhibitory rate of >97%. Furthermore, C10 significantly reduced cell death and relieved cellular morphological damage in SVCV-infected cells. Decreased mitochondrial membrane potential (ΔΨm) also suggested that C10 not only protected mitochondria, but also reduced apoptosis in SVCV-infected cells. For in vivo studies, intraperitoneal injection of C10 resulted in an anti-SVCV effect and substantially enhanced the survival rate of virus-infected zebrafish. Furthermore, C10 significantly enhanced antioxidant enzyme activities and decreased reactive oxygen species (ROS) to maintain antioxidant-oxidant balance within the host, thereby contributing to inhibition of SVCV replication. The up-regulation of six interferon (IFN)-related genes also demonstrated that C10 indirectly activated IFNs for the clearance of SVCV in zebrafish. This was beneficial for the continuous maintenance of antiviral effects because of the low viral loads in fish. Thus, C10 is suggested as a therapeutic agent with great potential against SVCV infection in aquaculture.

Iodine-mediated formal [3 + 2] annulation for synthesis of furocoumarin from oxime esters

A novel synthesis of furocoumarins was developed by a reaction between oxime esters and 4-hydroxycoumarins. The reaction was proposed to undergo radical mechanism mediated by iodine, a cheap and common laboratory reagent. Mechanistic studies showed the key for the successful transformation was the presence of α-iodoimine intermediate which facilitated the ring-closing step. The developed conditions produced good functional group tolerance with a wide range of high-profile furocoumarin product. The potential for this strategy to be applied in other syntheses of heterocyclic compounds is highly achievable.

A novel synthesis of furocoumarins was developed by a reaction between oxime esters and 4-hydroxycoumarins.

Gut Metabolism of Furanocoumarins: Proposed Function of Co O-Methyltransferase

Gut metabolism of natural products is of great interest due to the altered biological activity of the metabolites. To study the gut metabolism of the dietary furanocoumarins, the biotransformation of Angelica dahurica was studied with human gut microbiota. The major components of Avenula dahurica, including xanthotoxin (1), bergapten (2), imperatorin (3), isoimperatorin (4), oxypeucedanin (5), and byakangelicol (6), were all metabolized by the human fecal sample, and each furanocoumarin was also biotransformed by Blautia sp. MRG-PMF1 responsible for intestinal O-demethylation. Oxypeucedanin (5) and byakangelicol (6) were converted to oxypeucedanin hydrate (9) and desmethylbyakangelicin (12), respectively. The gut microbial conversion of xanthotoxin (1) and bergapten (2) with the MRG-PMF1 strain resulted in the production of xanthotoxol (7) and bergaptol (8), respectively, due to the methyl aryl ether cleavage by O-methyltransferase. Unexpectedly, the biotransformation of prenylated furanocoumarins, imperatorin (3), and isoimperatorin (4) resulted in the corresponding deprenylated furanocoumarins of xanthotoxol (7) and bergaptol (8), respectively. The cleavage of the prenyl aryl ether group by gut microbiota was unprecedented metabolism. Our data presented the first deprenylation of prenylated natural products, presumably by the anaerobic prenyl aryl ether cleavage reaction catalyzed by Co-corrinoid enzyme.

Inhibitory Effect of Imperatorin on the Pharmacokinetics of Diazepam In Vitro and In Vivo

Background

Diazepam is a benzodiazepine drug used to treat anxiety, insomnia, and muscle spasms. Imperatorin is a phytochemical isolated from medicinal plants and is widely used in herbal medicine. The aim of this study was to investigate the interactions between imperatorin and diazepam in vitro and in vivo and to provide evidence-based guidance for the safe clinical use of the drug.

Methods

In vitro inhibition of imperatorin was assessed by incubating rat liver microsomes with diazepam to determine IC₅₀ values and the type of inhibition. For in vivo assessment, six rats were pretreated with 50 mg/kg imperatorin for two weeks, six were administered saline, and a single dose of 10 mg/kg diazepam was administered orally to both groups 30 min after the administration of imperatorin.

Results

Imperatorin inhibited the in vitro metabolism of diazepam via the competitive mechanism of CYP450. The IC₅₀ values of imperatorin to nordazepam and temazepam were 1.54 μM and 1.80 μM, respectively. The inhibitory constant values for temazepam and nordazepam were 1.24 μM and 1.29 μM, respectively. Long-term administration of imperatorin significantly increased the AUC_(0-12h), AUC_(0-∞), and Cmax of diazepam, while Vz/F and CLz/F were decreased significantly (P < 0.05). In turn, the AUC_(0-12h), AUC_(0-∞), and Cmax of nordazepam and temazepam decreased significantly, and Vz/F and CLz/F increased significantly (P < 0.05).

Conclusions

This study demonstrates that imperatorin inhibits the metabolism of diazepam both in vitro and in vivo. These results indicated that more attention should be paid when taking diazepam together with food or herbs containing IMP, although further investigation is still needed.

Synthesis and biological evaluation of novel biphenyl-furocoumarin derivatives as vasodilator agents

A series of novel biphenyl-furocoumarin derivatives were synthesized based on the nuclear structure of imperatorin and identified by IR, ¹H NMR, ¹³C NMR and MS, and evaluated for their ability to relax vessel on isolated rat mesenteric artery, basilar artery and renal artery, respectively. The majority of compounds demonstrated potent vasodilatation, and compound 8e expressed the highest activity (EC₅₀ = 0.56 μM) in MA. Compounds with fluorine at 2-position of 5-phenyl get better activity than others with chlorine or bromine, and the compounds containing a bulky structure had relatively low activity, such as 8c (EC₅₀ = 22.39 μM) in MA. As a follow-up, 8e, 10e, and 8c were docked into L-calcium channel (PDB code: 3G43) to explain the difference in the activity of the compounds.

Imperatorin alleviates ROS-mediated airway remodeling by targeting the Nrf2/HO-1 signaling pathway

In this study, we investigated the role and mechanism of imperatorin (IMP) in chronic inflammation and airway remodeling. The levels of TNF-α, IL-1β, IL-6, IL-8, VEGF, α-SMA, and ROS were detected by ELISA, immunohistochemistry (IHC), immunofluorescence, and Western blot. In addition, we evaluated the effect of IMP on MAPK, PI3K/Akt, NF-κB, and Nrf2/HO-1 signaling pathways. IMP treatment obviously attenuated the production of inflammatory cytokines and inflammatory cells in bronchoalveolar lavage fluid of OVA-induced airway remodeling model. Meanwhile, it significantly inhibited inflammatory cell infiltration, goblet cell hyperplasia, collagen deposition, VEGF production, α-SMA, and ROS expression. Our study has shown that IMP could regulate the signaling pathways including MAPK, PI3K/Akt, NF-κB, and Nrf2/HO-1 to release the inflammatory responses. IMP might attenuate airway remodeling by the down-regulation of Nrf2/HO-1/ROS/PI3K/Akt, Nrf2/HO-1/ROS/MAPK, and Nrf2/HO-1/ROS/NF-κB signaling pathways.

Effects of imperatorin in the cardiovascular system and cancer

Patients with cancer survivors are at increased risk of cardiovascular disease(CVD). Cardio-oncology has developed as a new discipline with the advances in cancer treatment. There are many new challenges for the clinician and a new frontier for research and investigation. There is an urgent need for further study on the prevention of cardiovascular toxicity. Imperatorin (IMP) is a natural form of coumarin and extract from several plants with diver's pharmacokinetic effects, including antioxidant and anti-inflammatory properties. This review focus on the molecular mechanisms and pharmacological effects of Imperatorin maybe provide potential cancer and cardiovascular protection that targets IMP. Further studies are required to elucidate the entire spectrum of cytotoxic activities of these compounds to validate and expand their preclinical and clinical applications and to clarify the potential role of IMP.

New strategy for identifying potential natural HIV-1 non-nucleoside reverse transcriptase inhibitors against drug-resistance: an in silico study

Non-nucleosides reverse transcriptase inhibitors (NNRTIs), specifically targeting the HIV-1 reverse transcriptase (RT), play a unique role in anti-AIDS agents due to their high antiviral potency, structural diversity, and low toxicity in antiretroviral combination therapies used to treat HIV. However, due to the emergence of new drug-resistant strains, the development of novel NNRTIs with adequate potency, improved resistance profiles and less toxicity is highly required. In this work, a novel virtual screening strategy combined with structure-based drug design was proposed to discover the potential inhibitors against drug-resistant HIV strains. Seven structure-variant RTs, ranging from the wild type to a hypothetical multi-mutant were regarded as target proteins to perform structure-based virtual screening. Totally 23 small molecules with good binding affinity were identified from the Traditional Chinese Medicine database (TCM) as potential NNRTIs candidates. Among these hits, (+)-Hinokinin has confirmed anti-HIV activity, and some hits are structurally identical with anti-HIV compounds. Almost all these hits are consistent with external experimental results. Molecular simulations analysis revealed that top 2 hits (Pallidisetin A and Pallidisetin B) bind stably and in high affinity to HIV-RT, which are ready to be experimental confirmed. These results suggested that the strategy we proposed is feasible, trustworthy and effective. Our finding might be helpful in the identification of novel NNRTIs against drug-resistant, and also provide a new clue for the discovery of HIV drugs in natural products.Communicated by Ramaswamy H. Sarma.

Imperatorin Suppresses Anaphylactic Reaction and IgE-Mediated Allergic Responses by Inhibiting Multiple Steps of FceRI Signaling in Mast Cells: IMP Alleviates Allergic Responses in PCA

This study is to investigate the effects of imperatorin (IMP) on allergic responses mediated by mast cells, both in vitro and in vivo. Passive cutaneous anaphylaxis (PCA) model was established. Histological detection was performed to assess the ear histology. ELISA and Western blot analysis were used to detect the levels of corresponding cytokines and signalling pathway proteins. IMP decreased the leakage of Evans blue and the ear thickness in the PCA models, in a dose-dependent manner, and alleviated the degranulation of mast cells. Moreover, IMP reduced the expression of TNF-α, IL-4, IL-1β, IL-8, and IL-13. Furthermore, IMP inhibited the phosphorylation levels of Syk, Lyn, PLC-γ1, and Gab2, as well as the downstream MAPK, PI3K/AKT, and NF-κB signaling pathways. In addition, IMP inhibited the mast cell-mediated allergic responses through the Nrf2/HO-1 pathway. IMP attenuates the allergic responses through inhibiting the degranulation and decreasing the expression levels of proinflammatory cytokines in the mast cells, involving the PI3K/Akt, MAPK, NF-κB, and Nrf2/HO-1 pathways.

Design, synthesis, and evaluation of new series of Imperatorin analogs with potential vasodilatory activity

Two series of imperatorin analogs were synthesized based on our previous research and evaluated for their vasodilatation activities on in vitro rat mesenteric artery, basilar artery, and renal artery ring models. Target compounds were characterized by infrared, ¹H NMR, and mass spectra. Most derivatives possessed significant vasodilatory activity on the mesenteric artery, and compound 3a exhibited favorable and broad vasodilatation activities on three kinds of rat artery ring models. The pharmacological results indicated that introducing nitrogen-contained ring in side chain or large steric hindrance at the distal end could increase the vasodilatory activity. Further, replacement of oxygen atom (-O-) in the skeleton of furocoumarin derivatives with nitrogen (-NH-) could cause the decrease of vasodilatory activity. The molecular docking also indicated that compound 3a showed a best affinity with α-1C receptor (PDB ID: 3G43). All these results suggested compound 3a would be a potential vasodilatory agent for hypertension.

Biomolecular Targets of Oxyprenylated Phenylpropanoids and Polyketides

Oxyprenylated secondary metabolites (e.g. phenylpropanoids and polyketides) represent a rare class of natural compounds. Over the past two decades, this group of phytochemicals has become a topic of intense research activity by several teams worldwide due to their in vitro and in vivo pharmacological activities, and to their great therapeutic and nutraceutical potential for the chemoprevention of acute and chronic diseases affecting humans. Such investigations have provided evidence that oxyprenylated secondary metabolites are able to interact with several biological targets at different levels accounting for their observed anticarcinogenic, anti-inflammatory, neuroprotective, immunomodulatory, antihypertensive, and metabolic effects. The aim of the present contribution is to provide a detailed survey of the so far reported data on the capacities of selected oxyprenylated phenylpropanoids and polyketides to trigger receptors, enzymes, and other types of cellular factors for which they exhibit a high degree of affinity and therefore evoke specific responses. With respect to the rather small amounts of these compounds available from natural sources, their chemical synthesis is also highlighted.

Blood-to-Retina Transport of Imperatorin Involves the Carrier-Mediated Transporter System at the Inner Blood-Retinal Barrier

This study investigated the mechanism of transporting imperatorin across the inner blood-retinal barrier (iBRB). The carotid artery single injection method was used to calculate the retinal uptake index (RUI) of [³H]imperatorin in vivo, whereas the retinal capillary endothelial cell lines were used for the in vitro uptake and mRNA expression assays. RUI value of [³H]imperatorin was greater than that of the reference compound ([¹⁴C]n-butanol). [³H]Imperatorin significantly reduced the RUI in the presence of neuroprotective organic cationic drugs at 10 mM. However, tetraethylammonium and p-aminohippuric acid showed no significant effects. [³H]Imperatorin uptake by TR-iBRB2 cells was time-, pH-, energy-, and concentration-dependent with a K_m value of 679 ± 130 μM. In addition, the uptake study showed insensitivity to sodium and membrane potential. Various organic cations including pyrilamine, nicotine, and clonidine significantly reduced the uptake of [³H]imperatorin, whereas organic anions and monocarboxylic acids did not. Furthermore, the mRNA expression level dropped markedly with rOCTN1, rOCTN2, rPMAT, and rMATE1 small interfering RNAs in the transfection study. Moreover, [³H]imperatorin uptake remained neutral with small interfering RNA transfections. Our results indicate that imperatorin transport across the iBRB involves carrier-mediated transporter system.

Synthesis and Characterisation of Novel 3-(4-Benzoyl-5-Phenylfuran-2-yl) Coumarins

Novel 3-(4-benzoyl-5-phenylfuran-2-yl)coumarin derivates were synthesised via a simple three-step reaction from salicylic aldehydes, ethyl 3-oxobutanoate and 1,3-diphenylpropane-1,3-dione. The synthesised compounds were characterised by NMR, MS and elemental analyses and single-crystal X-ray diffraction analysis.

Reversal Effect of Oxypeucedanin on P-glycoprotein-mediated Drug Transport

P-glycoprotein affects the transport of numerous drugs including chemotherapeutic drugs vincristine sulfate (VCR) and docetaxel (DTX), and is one of the main causes for multidrug resistance. Our previous studies have shown that oxypeucedanin (OPD) can enhance the intestinal transit of puerarin and VCR. However, the underlying mechanism is unclear. This study investigated the potential mechanism by which OPD improves P-gp-mediated drug transport. Molecular docking was performed to predict the binding force between OPD and P-gp and the contribution of OPD on P-gp activity. We observed the effect of OPD on the transport of VCR in MDCK-MDR1 cell monolayer and also measured the plasma pharmacokinetic parameters of DTX in the presence and absence of OPD by LC-MS/MS. Moreover, we further investigated the reversal mechanism of OPD on P-gp-mediated drug transport by determining the intracellular accumulation of Rhodamine-123 (Rh123) and P-gp ATPase activity as well as protein expression and mRNA level of P-gp. Our molecular docking results revealed that the binding force between OPD and P-gp was much lower than that between P-gp and verapamil (a P-gp substrate). The transport study in vitro indicated that OPD increased the flux of VCR across MDCK-MDR1 cell monolayer. The in vivo pharmacokinetic parameters data showed OPD increased the absorption of DTX. OPD activated P-gp ATPase activity and enhanced intracellular accumulation of Rh123 in MDCK-MDR1 cells. Western blotting and qRT-PCR outcomes indicated that OPD suppressed P-gp protein expression as well as downregulated P-gp mRNA level. Thus, OPD reverse P-gp-mediated drug transport via inhibition of P-gp activity and P-gp protein expression as well as downregulation of P-gp mRNA level. Our results suggest that OPD could reverse P-gp-mediated drug resistance in tumor cells.

Pharmacological and Nutritional Effects of Natural Coumarins and Their Structure-Activity Relationships

Coumarins are fused benzene and pyrone ring systems with a wide spectrum of bioactivities, including antitumor, anti-inflammation, antiviral, and antibacterial effects. In this paper, the current development of coumarin-based drugs is introduced, and their structure-activity relationship is discussed by reviewing the relevant literature published in the past 20 years. Coumarin molecules can be customized by the target site to prevent systemic side effects by virtue of structural modification. The ortho-phenolic hydroxyl on the benzene ring has remarkable antioxidant and antitumor activities. Coumarins with aryl groups at the C-4 position have good activities in anti-HIV, antitumor, anti-inflammation, and analgesia. C-3 phenylcoumarins have strong anti-HIV and antioxidant effects. Tetracycline pyranocoumarins can significantly inhibit HIV; osthol structural analogues have antimicrobial activity. Praeruptorin C and its derivatives play an important role in lowering blood pressure and dilating coronary arteries, and khellactone derivatives have significant inhibitory effects on AIDS, cancer, and cardiovascular diseases. It is concluded that the specific site on the core structure of coumarin exhibits one or more activities due to the electronic or steric effects of the substituents. This review is intended to be conducive to rational design and development of more active and less toxic agents with a coumarin scaffold.

Structural characterization of aluminium(iii) and iron(iii) complexes of coumarinic acid in aqueous solutions from combined experimental and theoretical investigations

The Al(iii) ion forms bidentate complexes involving a 6-membered ring by binding both the carboxyl oxygens of the ligand. In contrast, the Fe(iii) ion preferentially forms monodentate tetrahedral complexes.

Recent Advances on Bioactive Constituents in Ferula

Preclinical Research The genus Ferula (Umbelliferea) is widely distributed across Central Asia and the Mediterranean. Some plants of the genus Ferula have been used as sources of pharmaceuticals for centuries. Ferula is a rich source of biologically active compounds, including coumarin derivatives, sesquiterpene-substituted compounds, daucane esters, humulane, and germacrane compounds, aromatic lactones and disulfide compounds. Therefore, utilizing these bioactive constituents with antimicrobial and insecticidal effects not only can provide a new strategy for developing drug and green pesticide, but also protect endangered plant resources. In the present review, research advances on the bioactive constituents of the genus Ferula the plant sources. Drug Dev Res 78 : 321-331, 2017. © 2017 Wiley Periodicals, Inc.

Imperatorin is Transported through Blood-Brain Barrier by Carrier-Mediated Transporters

Imperatorin, a major bioactive furanocoumarin with multifunctions, can be used for treating neurodegenerative diseases. In this study, we investigated the characteristics of imperatorin transport in the brain. Experiments of the present study were designed to study imperatorin transport across the blood-brain barrier both in vivo and in vitro. In vivo study was performed in rats using single intravenous injection and in situ carotid artery perfusion technique. Conditionally immortalized rat brain capillary endothelial cells were as an in vitro model of blood-brain barrier to examine the transport mechanism of imperatorin. Brain distribution volume of imperatorin was about 6 fold greater than that of sucrose, suggesting that the transport of imperatorin was through the blood-brain barrier in physiological state. Both in vivo and in vitro imperatorin transport studies demonstrated that imperatorin could be transported in a concentration-dependent manner with high affinity. Imperatorin uptake was dependent on proton gradient in an opposite direction. It was significantly reduced by pretreatment with sodium azide. However, its uptake was not inhibited by replacing extracellular sodium with potassium or N-methylglucamine. The uptake of imperatorin was inhibited by various cationic compounds, but not inhibited by TEA, choline and organic anion substances. Transfection of plasma membrane monoamine transporter, organic cation transporter 2 and organic cation/carnitine transporter 2/1 siRNA failed to alter imperatorin transport in brain capillary endothelial cells. Especially, tramadol, clonidine and pyrilamine inhibited the uptake of [³H]imperatorin competitively. Therefore, imperatorin is actively transported from blood to brain across the blood-brain barrier by passive and carrier-mediated transporter.

Imperatorin protects H9c2 cardiomyoblasts cells from hypoxia/reoxygenation-induced injury through activation of ERK signaling pathway

BACKGROUND

Imperatorin is a compound found in plants and has been widely used in Chinese medicine for many years. It has many pharmacological effects, including the recently reported anti-apoptotic function, however, the mechanism largely remains unclear. This study is aimed to elucidate the mechanism of Imperatorin's anti-apoptotic function.

METHODS

A model of hypoxia and reoxygenation (H/R) treated h9c2 cardiomyoblasts was successfully constructed. The cells were treated with H/R condition, and followed by adding Imperatorin alone, Imperatorin with ERK inhibitor and/or ERK inhibitor alone, to examine the cell viability by Cell Counting Kit-8 assay, cell apoptosis rate by flow cytometry, and ERK expression by Western-blot under different conditions.

RESULTS

The results showed that imperatorin exerted protective effect on h9c2 cells from H/R injure. It was also found that it not only increased cell viability but also reduced the apoptotic rate for H/R treated h9c2 cells. The experiments also demonstrated that imperatorin could upregulate the expression levels of both ERK1 and ERK2, which is a key step in ERK signaling pathway activation.

CONCLUSIONS

These findings provided evidence that imperatorin could increase the cell viability and lower apoptotic rate in H/R treated h9c2 cells, and could also enhance the expression of ERK1/ERK2, demonstrating imperatorin's protective effect on H/R injured h9c2 cells through ERK signaling pathway.

Anisucoumaramide, a Bioactive Coumarin from Clausena anisum-olens

A new coumarin, anisucoumaramide (1), and a new δ-truxinate derivative, anisumic acid (2), were isolated from Clausena anisum-olens. Their structures were elucidated from extensive NMR and MS data. The absolute configurations of the coumarins were assigned using the experimental and calculated electronic circular dichroism data. Anisucoumaramide (1) represents the first example of a naturally occurring coumarin of which the terpenoidal side chain does not comply with the biosynthesis isoprene rule due to the presence of an unprecedented acetamido motif directly connected with the terpenoidal side chain. The δ-truxinate derivative was isolated from Clausena species for the first time. Compound 1 showed high selectivity for the MAO-B isoenzyme and inhibitory activity in the nanomolar range. Putative biosynthesis pathways toward 1 and 2 are proposed.

Therapeutic potential of coumarins as antiviral agents

Coumarins have received a considerable attention in the last three decades as a lead structures for the discovery of orally bioavailable non-peptidic antiviral agents. A lot of structurally diverse coumarins analogues were found to display remarkable array of affinity with the different molecular targets for antiviral agents and slight modifications around the central motif result in pronounced changes in its antiviral spectrum. This manuscript thoroughly reviews the design, discovery and structure-activity relationship studies of the coumarin analogues as antiviral agents focusing mainly on lead optimization and its development into clinical candidates.

Imperatorin exerts antiallergic effects in Th2-mediated allergic asthma via induction of IL-10-producing regulatory T cells by modulating the function of dendritic cells

Imperatorin is a furanocoumarin compound which exists in many medicinal herbs and possesses various biological activities. Herein, we investigated the antiallergic effects of imperatorin in asthmatic mice and explored the immunomodulatory actions of imperatorin on immune cells. We used a murine model of ovalbumin (OVA)-induced asthma to evaluate the therapeutic potential of imperatorin. Additionally, bone marrow-derived dendritic cells (DCs; BMDCs) were used to clarify whether imperatorin exerts an antiallergic effect through altering the ability of DCs to regulate T cells. Oral administration of imperatorin to OVA-sensitized and -challenged mice decreased serum OVA-specific immunoglobulin E (IgE) production, attenuated the airway hyperresponsiveness (AHR), and alleviated airway inflammation in a dose-dependent manner. Notably, secretions of Th2 cytokines and chemokines were reduced, and numbers of interleukin (IL)-10-producing regulatory T cells (Tregs) increased in imperatorin-treated mice. Imperatorin inhibited proinflammatory cytokines and IL-12 production but enhanced IL-10 secretion by lipopolysaccharide (LPS)-stimulated BMDCs. Compared to fully mature DCs, imperatorin-treated DCs expressed high levels of the inducible costimulatory ligand (ICOSL) and Jagged1 molecules, and had the regulatory capacity to promote the generation of IL-10-producing CD4(+) T cells in vitro. Additionally, imperatorin directly suppressed activated CD4(+) T-cell proliferation and cytokine production. Imperatorin may possess therapeutic potential against Th2-mediated allergic asthma not only via stimulating DC induction of Tregs but also via direct inhibition of Th2 cell activation. These findings provide new insights into how imperatorin affects the Th2 immune response and the development of imperatorin as a Treg-type immunomodulatory agent to treat allergic asthma.