Imperatorin interacts additively with novel antiseizure medications in the mouse maximal electroshock-induced seizure model: an isobolographic transformation

BACKGROUND

Anticonvulsant effects of imperatorin (IMP) have been experimentally confirmed earlier, but no information is available on the interaction profiles of this naturally occurring coumarin when combined with novel antiseizure medication (ASMs). This study aimed to determine the effects of IMP on the anticonvulsant effects of lacosamide (LCM), oxcarbazepine (OXC), pregabalin (PGB), and topiramate (TPM) in the maximal electroshock-induced seizure (MES) model in mice.

METHODS

The anticonvulsant effects exerted by novel ASMs (LCM, OXC, PGB, and TPM) when combined with constant doses of IMP (25 and 50 mg/kg) underwent isobolographic transformation to precisely classify the observed interactions in the mouse MES model. Total brain concentrations of ASMs were measured with high-pressure liquid chromatography to exclude the pharmacokinetic nature of interactions among IMP and the tested ASMs.

RESULTS

IMP (50 mg/kg) significantly enhanced (p < 0.01) the anticonvulsant potency of LCM, OXC, PGB, and TPM in the mouse MES model. IMP (25 mg/kg) mildly potentiated the anticonvulsant action of LCM, OXC, PGB, and TPM, but no statistical significance was reported for these combinations. The isobolographic transformation of data from the MES test revealed that the interactions of novel ASMs with IMP were additive. Moreover, IMP (50 mg/kg) did not affect the total brain content of any of the novel ASMs in experimental mice.

CONCLUSIONS

The additive interactions of IMP with LCM, OXC, PGB, and TPM in the mouse MES model accompanied by no pharmacokinetic changes in the total brain content of ASMs are worthy of recommendation for further studies.

Imperatorin ameliorates kidney injury in diabetic mice by regulating the TGF-β/Smad2/3 signaling axis, epithelial-to-mesenchymal transition, and renal inflammation

Diabetic nephropathy (DN) is a serious concern in patients with diabetes mellitus. Prolonged hyperglycemia induces oxidative damage, chronic inflammation, and build-up of extracellular matrix (ECM) components in the renal cells, leading to kidney structural and functional changes. Imperatorin (IMP) is a naturally occurring furanocoumarin derivative with proven antioxidative and anti-inflammatory properties. We investigated whether IMP could improve DN and employed high glucose (HG)-induced HK-2 cells and high-fat diet-fed streptozotocin (HFD/STZ)-generated DN experimental model in C57BL/6 mice. In vitro, IMP effectively reduced the HG-activated reactive oxygen species generation, disturbance in the mitochondrial membrane potential (MMP) and epithelial-to-mesenchymal transition (EMT)-related markers, and the transforming growth factor (TGF)-β and collagen 1 expression in HK-2 cells. In vivo, we found an elevation of serum creatinine, kidney histology alterations, and collagen build-up in the kidneys of the DN control group. Also, we found an altered expression of EMT-related markers, upregulation of the TGF-β/Smad2/3 axis, and elevated pro-inflammatory molecules, TNF-α, IL-1β, IL-18 and phospho-NF-kB (p65) in the DN control group. IMP treatment did not significantly reduce the blood glucose level compared to the DN control group. However, IMP treatment effectively improved renal damage by ameliorating kidney histological changes and serum renal injury markers. IMP treatment restored renal antioxidants and exhibited anti-inflammatory effects in the kidneys. Moreover, the abnormal manifestation of EMT-related attributes and elevated levels of TGF-β, phospho-Smad2/3, and collagen 1 were also normalized in the IMP treatment group. Our findings highlight that IMP may be a potential candidate for treating DN.

Effect of Angelica dahurica, Angelica dahurica polysaccharides, and imperatorin on free and bound heterocyclic amine generation in roasted beef patties and release profiles of bound heterocyclic amines during in vitro digestion

This study explored the suppressive activity of Angelica dahurica (AD), AD polysaccharides, and imperatorin on free and bound heterocyclic amine (HA) formation in roast beef patties and release profiles of bound HAs during in vitro digestion. The suppressive effects and potential mechanisms associated with free radical quenching were explored using UPLC-MS/MS, multivariate statistical analysis, and electron paramagnetic resonance (EPR). AD (0.5%, 1.0%, and 1.5%) and imperatorin (0.005%, 0.010%, and 0.015%) showed a dose-dependent inhibition for both free and bound HAs, with AD polysaccharides showing a slight inhibitory capacity. The maximum inhibition of free and bound HAs was 36.31% (1.5% AD) and 35.68% (0.015% imperatorin). The EPR results demonstrated that alkyl radicals and 1O2 were the pivotal free radicals for HAs. Furthermore, AD and imperatorin dose-dependently decreased the level of these radicals. Intriguingly, after in vitro digestion, only AD polysaccharides significantly inhibited the release of bound HAs, with imperatorin even facilitating the release process. In this study, the capacity of the AD polysaccharide to suppress the release of bound HAs and the ability of AD and imperatorin to inhibit free and bound HAs in beef patties were identified for the first time.

Imperatorin inhibits LPS-induced bone marrow-derived macrophages activation by decreased NF-κB p65 phosphorylation

BACKGROUND

Imperatorin (IMP) is a secondary metabolite of plants and is the most abundant in Angelica dahurica. Previous studies showed that IMP exhibited anti-inflammatory activity in RAW264.7 cell line. Here, we aim to investigate the roles and mechanisms of IMP in bone marrow-derived macrophages (BMDMs), in view of the difference between primary macrophages and cell lines.

METHODS

BMDMs were stimulated with LPS for the inflammation model. Flow cytometry was performed with BMDMs treated with different doses of IMP (0-20mg/L) within staining Annexin V-APC for 5 min. The cytokines and inflammatory mediators were detected by RT-PCR or ELISA. RNA-seq was performed in IMP-treated BMDMs or control, stimulated with LPS for 6h. Western blotting is carried out to determine the phosphorylation of p65, ERK1/2, JNK1, p38, and Akt.

RESULTS

Our results showed that IMP inhibited IL-12p40, IL-6, TNF-α and IL-1β in LPS-stimulated BMDMs. RNA-seq analysis suggested that IMP inhibits Toll-like receptor signaling pathway (KEGG), TNF signaling pathway (KEGG), NF-κB signaling pathway (KEGG), Inflammatory Response (GO). In addition, IMP inhibited myd88, tpl2, cxcl1, ptgs2(COX-2) expression in mRNA level. Finally, we found decreased phosphorylation of NF-κB p65 in IMP-treated BMDMs, after stimulated with LPS.

CONCLUSION

IMP inhibits IL-12p40, IL-6, TNF-α, and IL-1β expression in LPS-stimulated BMDMs. IMP inhibits macrophage activation, which maybe resulted in decreased phosphorylation of NF-κB p65. Furthermore, IMP may protect against the progress of inflammatory-related diseases.

Isolation of coumarins with anti-Trichophyton rubrum activity from Heracleum vicinum Boiss

Heracleum vicinum Boiss., a perennial plant of Angelica in Umbelliferae, is mainly distributed in Sichuan and Hunan of China. Trichophyton rubrum is a common skin fungus causing dermatophyte. The previous experimental study found that the ethanol extract from Heracleum vicinum Boiss. had excellent anti-Trichophyton rubrum activity, especially the ethanol extract further extracted with petroleum ether and dichloromethane has the best antibacterial effect and has good potential for treating dermatophytes. In this study, Heracleum vicinum Boiss. was extracted with ethanol by microwave-assisted ultrasonic extraction method and isolated with silica gel column to obtain a coumarin compound M1-1 by the guidance of anti-Trichophyton rubrum activity, which was characterized by nuclear magnetic resonance spectroscopy(13C-NMR), hydrogen nuclear magnetic resonance (1H-NMR), Fourier transform infrared spectroscopy (FTIR), high-resolution mass spectrometry (HR-ESI-MS), and ultraviolet (UV) and identified as imperatorin and belonged to coumarins, with the minimum inhibitory concentration (MIC) against Trichophyton rubrum of 12.5 μg/mL. According to the discussion on the inhibitory mechanism of the compound, we found that the compound may exert its inhibitory effect by destroying the mycelial membrane and inhibiting the mycelial growth of Trichophyton rubrum. In a word, imperatorin isolated from Heracleum vicinum Boiss. is expected to be used as an antibacterial agent to treat dermatophytes a potential natural compound against Trichophyton rubrum, and a template for drug development of dermatophytes the future.

Imperatorin induces autophagy and G0/G1 phase arrest via PTEN-PI3K-AKT-mTOR/p21 signaling pathway in human osteosarcoma cells in vitro and in vivo

BACKGROUND

Osteosarcoma is the third most common cancer in adolescence and the first common primary malignant tumor of bone. The long-term prognosis of osteosarcoma still remains unsatisfactory in the past decades. Therefore, development of novel therapeutic agents which are effective to osteosarcoma and are safe to normal tissue simultaneously is quite essential and urgent.

METHODS

Firstly, MTT assay, cell colony formation assay, cell migration and invasion assays were conducted to evaluate the inhibitory effects of imperatorin towards human osteosarcoma cells. RNA-sequence assay and bioinformatic analysis were then performed to filtrate and assume the potential imperatorin-induced cell death route and signaling pathway. Moreover, quantitative real-time PCR assay, western blot assay and rescue experiments were conducted to confirm the assumptions of bioinformatic analysis. Finally, a subcutaneous tumor-transplanted nude mouse model was established and applied to evaluate the internal effect of imperatorin on osteosarcoma by HE and immunohistochemistry staining.

RESULTS

Imperatorin triggered time-dependent and dose-dependent inhibition of tumor growth mainly by inducing autophagy promotion and G0/G1 phase arrest in vitro and in vivo. Besides, imperatorin treatment elevated the expression level of PTEN and p21, down-regulated the phosphorylation of AKT and mTOR. In contrast, the inhibition of PTEN using Bpv (HOpic), a potential and selective inhibitor of PTEN, concurrently rescued imperatorin-induced autophagy promotion, cell cycle arrest and inactivation of PTEN-PI3K-AKT-mTOR/p21 pathway.

CONCLUSIONS

This work firstly revealed that imperatorin induced autophagy and cell cycle arrest through PTEN-PI3K-AKT-mTOR/p21 signaling pathway by targeting and up-regulating PTEN in human osteosarcoma cells. Hence, imperatorin is a desirable candidate for clinical treatments of osteosarcoma.

Imperatorin alleviated NLR family pyrin domain-containing 3 inflammasome cascade-induced synovial fibrosis and synovitis in rats with knee osteoarthritis

We aimed to clarify the therapeutic effects of imperatorin (IMP) on knee osteoarthritis (KOA). Thirty 3-month-old SD male rats were randomly divided into Normal, monosodium iodoacetate (MIA) and MIA+IMP groups. Their synovial tissues were subjected to histopathological analysis. Primary synovial fibroblasts obtained from additional normal rats were treated by lipopolysaccharide (LPS) and then IMP. The mRNA and protein expressions of factors related to synovitis and synovial fibrosis were detected by qRT-PCR and Western blotting, respectively. The concentrations of inflammatory factors IL-1β and IL-18 were measured by ELISA. IMP reduced HIF-1α, NLR family pyrin domain-containing 3 inflammasome expression and IL-1β, IL-18 production in synovial fibroblasts induced by LPS. IMP also downregulated synovial fibrosis markers. In vitro study revealed that MIA-induced synovitis and synovial fibrosis were relieved by IMP. IMP relieves the inflammation associated with synovitis and synovial fibrosis. It reduces the production of pro-inflammatory mediators and cytokines and inhibits TGF-β1, TIMP-1 and VEGF expressions that promote synovial fibrosis.

Oxyprenylated Secondary Metabolites as Modulators of Lipid and Sugar Metabolism

O-Prenylcoumarins (3,3-dimethylallyl, geranyl-, farnesyl- and related biosynthetic derivatives) represent a class of rarely occurring natural compounds. The most part of these secondary metabolites have been obtained from plant species belonging to the Rutaceae, Apiaceae, andFabaceae families, and from fungi, and bacteria. In the last two decades prenyloxycoumarinshave been found to possess a great potential in terms of pharmacological activities. The aim of this comprehensive review is to make a survey of the in so far reported literature citations about these valuable phytochemicals and structurally related compounds about their modulatory properties of lipid and sugar metabolism. Literature data have been acquired from the main Internet database. Several oxyprenylated secondary metabolites have been surveyed. Among these prenyloxycoumarins represented the main group exerting displayed valuable effects as modulators of lipid and sugar metabolism. The title phytochemicals have been found in common edible and fruits vegetables already known to have beneficial effects to this concern, thus enforcing the nutraceutical role of these food plants. All compounds outlined in the present review article have a great potential for the next future for the prevention and management of acute and chronic metabolic disorders.

Imperatorin alleviates metabolic and vascular alterations in high-fat/high-fructose diet-fed rats by modulating adiponectin receptor 1, eNOS, and p47phox expression

In the present study, the therapeutic effects of imperatorin on metabolic and vascular alterations and possible underlying mechanisms were investigated in high-fat/high-fructose diet (HFFD)-fed rats. Male Sprague-Dawley rats were fed a high-fat diet plus 15% fructose in drinking water for 16 weeks. HFFD-fed rats were treated with imperatorin (15 or 30 mg/kg/day) for the last 4 weeks. In HFFD-fed rats, imperatorin significantly reduced obesity, hypertension, dyslipidemia, and insulin resistance. Imperatorin markedly improved vascular endothelial function and alleviated changes in vascular morphology. Furthermore, imperatorin treatment significantly increased the plasma levels of the nitric oxide metabolite and adiponectin, and upregulated adiponectin receptor 1 and endothelial nitric oxide synthase (eNOS) protein expression in the thoracic aorta. Imperatorin treatment decreased vascular superoxide anion production and downregulated aortic NADPH oxidase subunit p47phox protein expression. These findings indicated that imperatorin alleviates HFFD-induced metabolic and vascular alterations in rats. The possible underlying mechanism may involve the restoration of adiponectin receptor 1 and eNOS expression and suppression of p47phox expression.

Screening for inhibitory effects of crude drugs on furin-like enzymatic activities

The spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) contains a cleavage motif R-X-X-R for furin-like enzymes at the boundary of the S1/S2 subunits. The cleavage of the site by cellular proteases is essential for S protein activation and virus entry. We screened the inhibitory effects of crude drugs on in vitro furin-like enzymatic activities using a fluorogenic substrate with whole-cell lysates. Of the 124 crude drugs listed in the Japanese Pharmacopeia, aqueous ethanolic extract of Cnidii Monnieris Fructus, which is the dried fruit of Cnidium monnieri Cussion, significantly inhibited the furin-like enzymatic activities. We further fractionated the plant extract and isolated the two active compounds with the inhibitory activity, namely, imperatorin and osthole, whose IC₅₀ values were 1.45 mM and 9.45 µM, respectively. Our results indicated that Cnidii Monnieris Fructus might exert inhibitory effects on furin-like enzymatic activities, and that imperatorin and osthole of the crude drug could be potential inhibitors of the motif cleavage.

Active components of Bupleurum chinense and Angelica biserrata showed analgesic effects in formalin induced pain by acting on Nav1.7

ETHNOPHARMACOLOGY RELEVANCE

Pain is an unpleasant sensory and emotional experience, often accompanied by the occurrence of a variety of diseases. More than 800 kinds of traditional Chinese medicines (TCM) has now been reported for pain relief and several monomers have been developed into novel analgesic drugs. Bupleurum chinense and Angelica biserrata were representatives of the TCM that are currently available for the treatment of pain.

AIM OF THE STUDY

The study aims to detect the potential analgesic activity of each monomer of Bupleurum chinense and Angelica biserrata and to explore whether Nav1.7 is one of the targets for its analgesic activity.

MATERIALS AND METHODS

In this study, five monomers from Bupleurum chinense (Saikosaponin A, Saikosaponin B1, Saikosaponin B2, Saikosaponin C, Saikosaponin D) and five monomers from the Angelica biserrata (Osthole, Xanthotoxin, Imperatorin, Isoimperatorin, Psoralen) were examined by whole-cell patch-clamp on Nav1.7, which was closely associated with pain. Classical mouse pain models were also used to further verify the analgesic activity in vivo.

RESULTS

The results showed that monomers of Saikosaponins and Angelica biserrata all inhibited the peak currents of Nav1.7, indicating that Nav1.7 might be involved in the analgesic mechanism of Saikosaponins and Angelica biserrata. Among them, Saikosaponin A and Imperatorin showed the strongest inhibitory effect on Nav1.7. Furthermore, both Saikosaponin A and Imperatorin showed inhibitory effects on thermal pain and formalin-induced pain in phase II in vivo.

CONCLUSION

The results provide valuable information for future studies on the potential of TCM in alleviating pain.

Imperatorin alleviated endometriosis by inhibiting the activation of PI3K/Akt/NF-κB pathway in rats

AIMS

Most therapeutic drugs of endometriosis have been contraceptives but symptoms recur in up to 75% of cases, which makes it a presses need to try to find novel and safer therapeutic drugs. Imperatorin is a furanocoumarin existing in many plants, possessing multiple activities, including anti-inflammatory. The purpose of this study was to assess the effects and mechanisms of imperatorin in endometriosis.

MAIN METHODS

Ectopic endometrial volume and hematoxylin-eosin staining were used to estimate the effects of imperatorin in experimental endometriosis model rats. Potential mechanisms of imperatorin in endometriosis were systematically analyzed by network pharmacology and molecular docking. Western blotting and enzyme-linked immunosorbent assay were employed to evaluate proteins expression and cytokines levels in PI3K/Akt/NF-κB pathway.

KEY FINDINGS

Imperatorin could significantly inhibit the growth and ameliorate the histopathological features of ectopic endometrium in experimental endometriosis rats. Network pharmacology approaches showed that imperatorin might regulate inflammatory response and cellular function via primarily affecting PI3K-Akt pathway, Endocrine resistance, Th17 cell differentiation in endometriosis. Moreover, 7 core targets (PIK3CA, AKT1, SRC, MAPK8, MAPK14, ERBB2 and CCND1) resulted from the intersection of KEGG and PPI network topological analysis were used to dock with imperatorin, which indicated that imperatorin could preferably fit in the binding pocket of the above target proteins, except for CCND1. Lastly, imperatorin markedly inhibited the activation of PI3K/Akt/NF-κB pathway via suppressing the phosphorylation levels of PI3K, Akt and p65 in the ectopic endometrium tissue.

SIGNIFICANCE

Our findings revealed that imperatorin is a significant multi-target natural active ingredient for treatment endometriosis.

Imperatorin ameliorates mast cell-mediated allergic airway inflammation by inhibiting MRGPRX2 and CamKII/ERK signaling pathway

BACKGROUND

Allergic asthma is a common inflammatory lung disease associated with complex pathogenesis. Mast cell (MC) is one of the key drivers of allergic asthma, Mas-related G protein-coupled receptor X2 (MRGPRX2) on the MC could mediate MC activation and trigger a pseudo-allergic reaction. Imperatorin (IMP), the main active compound of Radix Angelicae Dahuricae, has been reported to exert various pharmacological effects. In this study, we focused on the therapeutical mechanism of IMP on MRGPRX2-induced pseudo-allergy and allergic asthma.

METHODS

We examined the effect of IMP on MRGPRX2 related mast cell activation in mouse peritoneal MC (MPMC), Human Laboratory of Allergic Disease 2 MCs (LAD2 cells) and Mrgprx2-expressing HEK293 cells. Molecular docking and Surface plasmon resonance (SPR) were taken to reveal the binding character between IMP and MRPGRX2. MRGPRX2 downstream proteins were also detected by western blotting. IgE-independent responses was evaluated by using passive cutaneous anaphylaxis (PCA) and active systemic anaphylaxis (ASA) models. The therapeutic effect of IMP on asthma was evaluated by a lung inflammation mouse model which was induced by ovalbumin (OVA).

RESULTS

IMP was found to reduce substance P (SP) induced calcium flux and suppressed degranulation of MC. SP can promote the phosphorylation of ERK and CamKII, which regulates the synthesis of inflammatory factors such as MIP-2 and TNF-α in MC. In vivo assays revealed that IMP can mitigate SP-induced mouse PCA and ASA. IMP could also mitigate lung inflammation in an OVA induced mice model by inhibiting MC activation in the lung tissue. Furthermore, IMP binds well to MRGPRX2 protein. The binding constant (KD) is 4.48 ± 0.49 × 10-7 M. The data suggeste that IMP is a novel inhibitor of MRGPRX2 to treat allergic asthma.

Imperatorin reduces the inflammatory response of atherosclerosis by regulating MAPKs signaling pathway in vivo and in vitro

Inflammation plays an important role in the process of atherosclerosis (AS). Inhibition of inflammation is an effective way to prevent AS. Imperatorin (IMP) is a kind of furan coumarin with various activities. In this study, the anti-inflammatory effect of IMP was explored in oxidized low-density lipoprotein (ox-LDL)-induced VSMCs and high fat diet (HFD)-induced ApoE^-/- mice. The results showed that IMP attenuated the elevation of TNF-α, IL-6, MCP-1 and NO induced by ox-LDL in supernatant of VSMCs. IMP has normalized the levels of serum lipids (TC, TG, LDL-C and HDL-C) and attenuated inflammatory cytokines in serum. IMP also improved pathological changes and lipid accumulation in aorta. Matrix metalloproteinase-2 (MMP-2) expression in aorta was down-regulated by IMP. IMP could inhibit the phosphorylation of MAPKs pathway in the aorta and VSMCs, resulting in a significant decrease in the contents of p-ERK 1/2, p-JNK and p-P38. Overall, IMP could exert anti-inflammatory effects in vivo and in vitro to interfere with AS.

Direct Targeting of CREB1 with Imperatorin Inhibits TGFβ2-ERK Signaling to Suppress Esophageal Cancer Metastasis

Metastasis accounts for 90% of cancer death worldwide, and effective therapeutic strategies are lacking. The aim of this work is to identify the key drivers in tumor metastasis and screen therapeutics for treatment of esophageal squamous cell carcinoma (ESCC). Gene Ontology analysis of The Cancer Genome Atlas (TCGA) gene expression datasets of ESCC patients with or without lympy metastasis identifies that TGFβ2 is highly enriched in the pathways essential for tumor metastasis and upregulates in the metastatic ESCC tumors. High TGFβ2 expression in ESCC correlates with metastasis and patient survival, and functionally contributes to tumor metastasis via activating extracellular signal-regulated kinases (ERK) signaling. By screening of a library consisting of 429 bioactive compounds, imperatorin is verified as a novel TGFβ2 inhibitor, with robustly suppressive effect on tumor metastasis in multiple mice models. Mechanistically, direct binding of imperatorin and CREB1 inhibits phosphorylation, nuclear translocation of CREB1, and its interaction with TGFβ2 promoter, represses TGFβ2 expression and fibroblasts-secreted CCL2, and then inactivates ERK signaling to block cancer invasion and abrogates the paracrine effects of fibroblasts on tumor angiogenesis and metastasis. Overall, the findings suggest the use of TGFβ2 as a diagnostic and prognostic biomarker and therapeutic target in ESCC, and supports the potential of imperatorin as a novel therapeutic strategy for cancer metastasis.

Imperatorin suppresses IL-1β-induced iNOS expression via inhibiting ERK-MAPK/AP1 signaling in primary human OA chondrocytes

Joint inflammation is a key player in the pathogenesis of osteoarthritis (OA). Imperatorin, a plant-derived small molecule has been reported to have anti-inflammatory properties; however, its effect on chondrocytes is not known. Here, we investigated the effects of Imperatorin on interleukin-1β (IL-1β) induced expression of inducible nitric oxide synthase (iNOS) and nitric oxide production in primary human OA chondrocytes and cartilage explants culture under pathological conditions and explored the associated signaling pathways. We pretreated chondrocytes or explants with Imperatorin (50 μM) followed by IL-1β (1 ng/ml), and the culture supernatant was used to determine the levels of nitrite production by Griess assay and chondrocytes were harvested to prepare cell lysate or RNA for gene expression analysis of iNOS by Western blot or qPCR and in explants by immunohistochemistry (IHC). Pretreatment of primary chondrocytes and cartilage explants with Imperatorin suppressed IL-1β induced expression of iNOS and NO production. Imperatorin blocked the IL-1β-induced phosphorylation of ERK-MAPK/AP1 signaling pathway to suppress iNOS expression. The role of ERK in the regulation of iNOS expression was verified by using ERK inhibitor. Interestingly, we also found that Imperatorin binds to iNOS protein and inhibits its activity in vitro. Our data demonstrated that Imperatorin possess strong anti-inflammatory activity and may be developed as a therapeutic agent for the management of OA.

Imperatorin alleviates cancer cachexia and prevents muscle wasting via directly inhibiting STAT3

Skeletal muscle wasting is the most remarkable phenotypic feature of cancer cachexia that increases the risk of morbidity and mortality. Imperatorin (IMP), a main bioactive component of Angelica dahurica Radix, has been reported to possess several pharmacological effects including potential anti-colitis, anti-arthritis and anti-tumor activities. In this work, we demonstrated that IMP is a promising agent for the treatment of muscle wasting in cancer cachexia. IMP (5-20 μM) dose-dependently attenuated TCM-induced C2C12 myotube atrophy and prevented the induction of E3 ubiquitin ligases muscle RING-finger containing protein-1 (MuRF1) and muscle atrophy Fbox protein (Atrogin-1/MAFbx). Moreove, IMP administration significantly improved chief features of cancer cachexia in vivo, with significant prevention of the loss of body weight and deleterious wasting of multiple tissues, including skeletal muscle, fat and kidney and decreased expression of MuRF1 and Atrogin-1 in cachectic muscles. Cellular signaling pathway analysis showed that IMP selectively inhibited the phosphorylation of signal transducer and activator of transcription 3 (STAT3) in vitro and in vivo, and surface plasmon resonance (SPR) affinity experiments further demonstrated IMP bound to STAT3 in a concentration-dependent resonance manner. Molecular docking results revealed that IMP binds to the SH2 domain of STAT3, forming a hydrogen bond interaction with Arg-609, and a Sigma-Pi interaction with Lys-591. Mechanism analysis demonstrated that STAT3 overexpression markedly weakens the improvements of IMP on myotube atrophy and muscle wasting of cancer cachexia, indicating that STAT3 mediated the therapeutic effect of IMP. All these favorable results indicated that IMP is a new potential therapeutic candidate for cancer cachexia.

Imperatorin: A review of its pharmacology, toxicity and pharmacokinetics

As a naturally occurring furanocoumarin, the medicinal value of imperatorin has been studied more and more. We hope to provide useful information for the further development of imperatorin by analyzing the literature of imperatorin in recent years. By collating the literature on the pharmacology of imperatorin, we found that the pharmacological activity of imperatorin is wide and imperatorin can be used for anti-cancer, neuroprotection, anti-inflammatory, anti-hypertension and antibacterial. In addition, we found that some researchers confirmed the toxicity of imperatorin. Pharmacokinetic studies demonstrated that oxidation metabolism is the main metabolic pathways of imperatorin. At present, the shortcomings of research on imperatorin mainly include: most pharmacological studies are concentrated in vitro, lacking enough in vivo experimental data; more and more studies showed that imperatorin has synergistic effect with other drugs in anticancer and other aspects, but lacking the detailed explanation of the mechanism of the synergistic effect; imperatorin has side effect, but it lacks enough experimental conclusions. Based on the above defects, we believe that more in vivo experiments of imperatorin should be carried out in the future; future research need to explore synergistic mechanisms of imperatorin with other drugs, especially in anticancer; the dose affects both the pharmacological activity and the side effect of imperatorin. The relationship between the dose and the two aspects need to be further studied in order to reduce the side effect. In addition, through structural modification of imperatorin, it is possible to improve the treatment effect and reduce side effect.

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.

Imperatorin improves in vitro porcine embryo development by reducing oxidative stress and autophagy

Imperatorin (IMP), a furanocoumarin derivative with many biological properties and pharmacological activities, is widely used as an antibacterial, anti-inflammatory, antiviral, anticancer, cardiovascular and neuroprotective agent. The purpose of this study was to explore the effects of IMP on early embryo development in pigs as well as the potential mechanisms. Our results showed that IMP can enhance the developmental competence of porcine early embryos. Supplementation of in vitro culture medium with 40 μM IMP significantly increased the blastocyst rate and total cell number. At the same time, apoptosis of blastocysts was also significantly decreased in the supplemented group compared with the control group, in accordance with the subsequent results of FAS and CASP3 gene expression analysis. Furthermore, IMP attenuated intracellular reactive oxygen species (ROS) generation, increased fluorescein diacetate (FDA) and glutathione (GSH) levels. Importantly, IMP not only improved the activity of mitochondria but also inhibited the occurrence of autophagy. In addition, pluripotency-related genes (OCT4, NANOG, and SOX2) and a growth and metabolism regulatory gene (mTOR) were upregulated after IMP supplementation on Day 7. These results demonstrate that IMP exerts a beneficial effect on preimplantation embryo development by reducing oxidative stress and autophagy.

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.

Anti-nociceptive and anti-inflammatory effect of imperatorin: evidences for involvement of COX-2, iNOS, NFκB and inflammatory cytokines

Aim: The objective of the current investigation was to explore the analgesic effect of naturally occurring furanocoumarin, imperatorin and the involvement of inducible cyclooxygenase (COX-2), inducible nitric oxide synthase (iNOS), NFκB and cytokines in the observed effect.Materials and methods: Anti-nociceptive effect was explored by inducing chemical hyperalgesia using acetic acid and formalin in mice. ED₅₀ of imperatorin was calculated in acetic acid model. Modulation of cyclooxygenase and nitric oxide pathway by imperatorin was examined by stimulator/precursor challenge with substance P and L-arginine, respectively and quantification of COX-2, iNOS and NFκB expression by immunohistochemical analysis in spinal tissues. Involvement of inflammatory cytokines TNF-α and IL-1β was investigated using LPS challenge and subsequent ELISA analysis of these inflammatory mediators in serum. Carrageenan inflicted paw edema was employed to explore the anti-inflammatory activity of imperatorin.Results: A significant reduction in the nociceptive behaviour was observed with imperatorin treatment in acetic acid and formalin test. ED₅₀ of imperatorin was found to be 4.53 mg/kg. Pre-treatment with substance P and L-arginine significantly attenuated the anti-nociceptive activity of imperatorin in formalin test. Immunohistochemical findings revealed marked decrease in spinal COX-2, iNOS and NFκB expression. Imperatorin administration significantly reduced LPS induced rise in level of TNF-α and IL-1β dose dependently. In carrageenan-induced paw edema test, maximum possible anti-inflammatory effect of imperatorin was evident after 240 min of carrageenan administration.Conclusion: Current investigation revealed that anti-nociceptive and anti-inflammatory potential of imperatorin is probably mediated through the attenuation of COX-2, iNOS, NFκB activity and reduction in circulatory cytokines.

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.

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 suppresses proliferation and angiogenesis of human colon cancer cell by targeting HIF-1α via the mTOR/p70S6K/4E-BP1 and MAPK pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Angelica dahurica is a commonly used traditional Chinese medicine to treat migraine headache, toothache and cancer. Imperatorin is an active natural furocoumarin component originating from Angelica dahurica and has been shown to exhibit multiple bioeffector functions, including anti-cancer activity. However, the mechanism by which imperatorin inhibits tumor growth is not fully understood.

AIM OF THE STUDY

The aim of this study was to investigate the effectiveness of imperatorin as a treatment of cancer and to identify the underlying mechanisms of its anticancer activity.

MATERIALS AND METHODS

HCT116, HeLa, and Hep3B cells were used in this study. Major assays were promoter-reporter gene assay, MTT, western blot analysis, immunofluorescence assay, reverse transcription-PCR (RT-PCR), flow cytometric analysis, clonogenic assay, EdU labeling and immunofluorescence, xenografted assay, and VEGF ELISA.

RESULTS

We here demonstrated the effect of imperatorin on hypoxia-inducible factor-1 (HIF-1) activation. Imperatorin showed a potent inhibitory activity against HIF-1 activation induced by hypoxia in various human cancer cell lines. This compound markedly decreased the hypoxia-induced accumulation of HIF-1α protein dose-dependently, whereas it did not affect the expressions of HIF-1β and topoisomerase-I (Topo-I). Further analysis revealed that imperatorin inhibited HIF-1α protein synthesis, without affecting the expression level of HIF-1α mRNA or degradation of HIF-1α protein. Moreover, the phosphorylation levels of mammalian target of rapamycin (mTOR), ribosomal protein S6 kinase (p70S6K), eIF4E binding protein-1 (4E-BP1), eukaryotic initiation factor 4E (eIF4E), extracellular signal-regulated kinase-1/2 (ERK1/2), SAPK/JNK and p38 were significantly suppressed by imperatorin. Furthermore, imperatorin prevented hypoxia-induced expression of HIF-1 target genes and flow cytometric analysis indicated that imperatorin induced G1 phase arrest in human colon cancer cell (HCT116). We found that imperatorin administration inhibits tumor growth and blocks tumor angiogenesis in a xenograft tumor model.

CONCLUSIONS

These results show that imperatorin inhibited HIF-1α protein synthesis by downregulating the mTOR/p70S6K/4E-BP1 and MAPK pathways. These conclusions suggest that imperatorin is an effective inhibitor of HIF-1 and provide new perspectives into the mechanism of its anticancer activity.

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.

Effects of Angelica dahurica on obesity and fatty liver in mice

Angelica dahurica (A. dahurica) is a traditional Chinese medicinal plant being used in clinical practice. The present study demonstrated that A. dahurica could reduce white-fat weight in high-fat-diet hyperlipidemic mice, decrease total cholesterol and triglyceride concentrations in the livers of both high-fat-diet and Triton WR1339 induced hyperlipidemic mice, and enhance the total hepatic lipase activities of them. These findings were further supported by the results derived from the experiments with HepG2 cells in vitro. In addition, the proteins related to lipids metabolism were investigated using LC-MS/MS, indicating that genes of lipid metabolism and lipid transport were regulated by A. dhurica. The results from LC-MS/MS were further conformed by Western blot and real time PCR assays. A. dahurica could down-regulate the expression of catalase (CAT) and sterol carrier protein2 (SCP2) and up-regulate the expression of lipid metabolism related genes-lipase member C (LIPC) and peroxisome proliferator-activated receptor gamma (PPARγ). In the Triton WR1339 mouse liver and HepG2 cells in vitro, A. dahurica was able to increase the expression of LIPC and PPARγ, confirming the results from in vivo experiments. Imperatorin showed the same activity as A. dahurica, suggesting it was one of the major active ingredients of the herb. In conclusion, our work represented a first investigation demonstrating that A. dahurica was able to regulate lipid metabolism and could be developed as a novel approach to fighting against fatty liver and obesity.

Estrogenic activity of osthole and imperatorin in MCF-7 cells and their osteoblastic effects in Saos-2 cells

There is an increasing interest in phytoestrogens due to their potential medical usage in hormone replacement therapy (HRT). The present study was designed to investigate the in vitro effects of estrogen-like activities of two widespread coumarins, osthole and imperatorin, using the MCF-7 cell proliferation assay and their alkaline phosphatase (ALP) activities in osteoblasts Saos-2 cells. The two compounds were found to strongly stimulate the proliferation of MCF-7 cells. The estrogen receptor-regulated ERα, progesterone receptor (PR) and PS2 mRNA levels were increased by treatment with osthole and imperatorin. All these effects were significantly inhibited by the specific estrogen receptor antagonist ICI182, 780. Cell cycle analysis revealed that their proliferation stimulatory effect was associated with a marked increase in the number of MCF-7 cells in S phase, which was similar to that observed with estradiol. It was also observed that they significantly increased ALP activity, which was reversed by ICI182,780. These results suggested that osthole and imperatorin could stimulate osteoblastic activity by displaying estrogenic properties or through the ER pathway. In conclusion, osthole and imperatorin may represent new pharmacological tools for the treatment of osteoporosis.

Differential mechanistic investigation of protective effects from imperatorin and sec-O-glucosylhamaudol against arsenic trioxide-induced cytotoxicity in vitro

BACKGROUND AND PURPOSE

The clinical use of arsenic trioxide (As₂O₃) for treating acute promyelocytic leukemia (APL) is limited due to its severe cardiotoxicity. The possible mechanisms of As₂O₃-induced cardiotoxicity include DNA fragmentation, reactive oxygen species (ROS) generation, cardiac ion channel changes and apoptosis. The present study is designed to investigate the protective effects of imperatorin and sec-O-glucosylhamaudol and to explore their mechanistic involvement in As₂O₃-induced cytotoxicity.

EXPERIMENTAL METHODS

Cell viability assay, Lactate dehydrogenase (LDH) release, Acridine orange/ethidium bromide (AO/EB) double staining, Caspase-3 activity assay, ROS generation, cellular calcium levels, mRNA expression levels by qRT-PCR and protein expression levels by Western blotting were measured in H9c2 cells in combination with As₂O₃ and imperatorin or sec-O-glucosylhamaudol.

KEY RESULTS

We observed that H9c2 cells treated with imperatorin or sec-O-glucosylhamaudol were more resistant to As₂O₃-induced cell death. Both imperatorin and sec-O-glucosylhamaudol reduced H9c2 cell apoptosis, but both imperatorin and sec-O-glucosylhamaudol had no effects on Caspase-3 activity and intracellular calcium accumulation. Furthermore, imperatorin was capable of suppressing ROS generation, while sec-O-glucosylhamaudol did not show this effect. Moreover, imperatorin and sec-O-glucosylhamaudol triggered Nrf2 activation, which resulted in upregulation of downstream phase II metabolic enzymes and antioxidant protein/enzyme, probably offering cellular protection to As₂O₃-induced cardiotoxicity via the Nrf2 signal pathway.

CONCLUSIONS AND IMPLICATIONS

Imperatorin and sec-O-glucosylhamaudol can ameliorate As₂O₃-induced cytotoxicity and apoptosis in H9c2 cells, the mechanisms probably related to antioxidation. As₂O₃ in combination with imperatorin or sec-O-glucosylhamaudol could be considered as a novel strategy to expand the clinical application of As₂O₃.

Preventive effects of imperatorin on perfluorohexanesulfonate-induced neuronal apoptosis via inhibition of intracellular calcium-mediated ERK pathway

Early life neuronal exposure to environmental toxicants has been suggested to be an important etiology of neurodegenerative disease development. Perfluorohexanesulfonate (PFHxS), one of the major perfluoroalkyl compounds, is widely distributed environmental contaminants. We have reported that PFHxS induces neuronal apoptosis via ERK-mediated pathway. Imperatorin is a furanocoumarin found in various edible plants and has a wide range of pharmacological effects including neuroprotection. In this study, the effects of imperatorin on PFHxS-induced neuronal apoptosis and the underlying mechanisms are examined using cerebellar granule cells (CGC). CGC were isolated from seven-day old rats and were grown in culture for seven days. Caspase-3 activity and TUNEL staining were used to determine neuronal apoptosis. PFHxS-induced apoptosis of CGC was significantly reduced by imperatorin and PD98059, an ERK pathway inhibitor. PFHxS induced a persistent increase in intracellular calcium, which was significantly blocked by imperatorin, NMDA receptor antagonist, MK801 and the L-type voltage-dependent calcium channel blockers, diltiazem and nifedipine. The activation of caspase-3 by PFHxS was also inhibited by MK801, diltiazem and nifedipine. PFHxS-increased ERK activation was inhibited by imperatorin, MK801, diltiazem and nifedipine. Taken together, imperatorin protects CGC against PFHxS-induced apoptosis via inhibition of NMDA receptor/intracellular calcium-mediated ERK pathway.

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.

Imperatorin inhibits the expression of alpha-hemolysin in Staphylococcus aureus strain BAA-1717 (USA300)

Both community-associated and hospital-acquired infections with methicillin-resistant Staphylococcus aureus (MRSA) have been increasingly reported around the world in the past 20 years. In 2006, the Centers for Disease Control and Prevention reported that 64 % of MRSA isolates were of the USA300 clonal type in infected patients in USA. The aim of our study was to estimate the in vitro effect of imperatorin on MRSA strain BAA-1717 (USA300). The effects of imperatorin on alpha-hemolysin (Hla) production, when strain BAA-1717 was co-cultured with sub-inhibitory concentrations of imperatorin, were analysed using susceptibility testing, hemolysis assays, western blotting and real-time PCR. Live/Dead analysis and cytotoxicity assays were employed to examine the protective effect of imperatorin against the strain BAA-1717-mediated injury of human alveolar epithelial cells (A549). The results showed that imperatorin has no anti-S. aureus activity at the tested concentrations in vitro. However, imperatorin can observably inhibit the production of Hla in culture supernatants and reduce the transcriptional levels of hla (the gene encoding Hla) and arg (the accessory gene regulator). Imperatorin prevented Hla-mediated A549 epithelial cell injury in a co-culture system. In conclusion, our results suggested that imperatorin has the potential to be developed as a new anti-virulence drug candidate for managing S. aureus infection.

Imperatorin-pharmacological meaning and analytical clues: profound investigation

Imperatorin, a furanocoumarin derivative, has many documented pharmacological properties which make it a candidate for possible drug development. In this review, the activity on the central nervous system, the anticancer and antiviral properties and the influence on the cardiovascular system are described. The aim of this review is also to present an overview of the techniques used for the analysis, isolation, and separation of imperatorin from plant material from the practical perspective.

Imperatorin induces Mcl-1 degradation to cooperatively trigger Bax translocation and Bak activation to suppress drug-resistant human hepatoma

Imperatorin is a small molecule nature compound isolated from the root of Angelica dahurica, and has been shown to exhibit multiple bioeffector functions, including anti-cancer activity. However, the molecular mechanism underlying imperatorin in suppression of tumor growth is unknown. In this study, we aimed at elucidating the molecular mechanisms underlying imperatorin function and determining the efficacy of imperatorin in suppression of drug-resistant human liver cancer. We observed that imperatorin suppresses tumor cell growth through inducing apoptosis, and imperatorin is more effective in induction of multidrug-resistant human liver cancer cells in vitro. We further determined that imperatorin induces apoptosis through both extrinsic and intrinsic apoptosis pathway. At the molecular level, we identified Mcl-1 as the molecular target of imperatorin and determined that imperatorin induces proteosome-dependent Mcl-1 degradation to release Bak and Bax to trigger apoptosis in liver cancer cells. Consistent with its in vitro apoptosis induction activity, imperatorin exhibited potent activity against multidrug-resistant liver cancer xenograft growth in vivo. Taken together, we determined that imperatorin is a Mcl-1 degradation inducer that can effectively suppress multidrug-resistant human liver cancer growth in vivo, and thus holds great promise for development as an effective small molecule anti-cancer agent in human liver cancer therapy to overcome drug resistance.

Vasodilation and radical-scavenging activity of imperatorin and selected coumarinic and flavonoid compounds from genus Casimiroa

Hypertension is a very widespread condition which is not strictly considered as an illness but if not countered, progressively causes damage to all tissues and loss in their functionality. For this reason the find of new antihypertensive agents is prominent and medicinal plants and their derivatives are valuable for the purpose. The genus Casimiroa (Rutaceae) includes plants from Central America and Mexico; among these, Casimiroa edulis Llave et Lex. and Casimiroa pubescens Ramirez are the most relevant species, even for their medicinal uses. The decoction of leaves and seeds is traditionally taken as a tea mainly to lower blood pressure. The object of this research was the study of vascular activity of coumarinic and flavonoid compounds isolated from seeds of Casimiroa spp. in comparison with Casimiroa edulis and Casimiroa pubescens extracts. The phenolic compounds isolated from Casimiroa were herniarin (Her), imperatorin (Imp), 8-geranyloxypsoralen (GOP) and 5,6,2',3',4'-pentamethoxyflavone (PMF). All these compounds induced vasorelaxation on rat arterial tissues although with different effectiveness. To study the cellular mechanisms of the vasorelaxation exhibited by imperatorin, we used selective inhibitors of different receptors and enzymes, such as atropine, pyrilamine, nifedipine, L-NAME and DETC. In a further step of this research, we evaluated the radical-scavenging activity of Casimiroa extracts and isolated compounds by means of DPPH assay. In general, we observed that the scavenging activities increased in a concentration-dependent manner for all substances. The phenolic compounds highlight a synergism of vasodilation and antioxidant activity which may be very useful in the management of cardiovascular diseases. Among the evaluated compounds, imperatorin shows a significant vasorelaxant activity even higher than acetylcholine and similar to nitrite, and also useful antiradical capabilities. All these properties suggest its possible role against hypertension and vasculopathies, even if in vivo studies are needed to determine the actual applications.

The effect of quercetin and imperatorin on programmed cell death induction in T98G cells in vitro

BACKGROUND

High expression of HSP27 and HSP72 in glioma cells has been closely associated with chemoresistance and decreased sensitivity to programmed cell death induction. Therefore, it is important to devise therapies that effectively target invasive cancer cells by inducing cell death. The aim of our study was to assess the effect of quercetin and imperatorin applied separately and in combinations on the apoptosis and autophagy induction in human T98G cells cultured in vitro.

METHODS

Cell death induction was analyzed by the staining method. The Western blotting technique and fluorimetric measurements of activity were used to assess the expression of marker proteins of apoptosis and autophagy. The specific siRNA transfected method was used for blocking of the expression of HSP27 and HSP72 genes.

RESULTS

The experiments revealed the highest percentage of apoptotic cells after using a 50?M concentration of both compounds. Simultaneous quercetin and imperatorin administration induced apoptosis more effectively than incubation with single drugs. These results were accompanied with decreased HSP27 and HSP72 expression, and a high level of caspase-3 and caspase-9 activity. Autophagy was not observed. Additional experiments were performed on a cell line with blocked Hsp27 and Hsp72 expression and significant increase the sensitivity to apoptosis induction upon quercetin and imperatorin treatment was noticed.

CONCLUSIONS

The present study indicates that quercetin and imperatorin are potent apoptosis inducers, especially when they act synergistically, which may be a promising combination useful in glioma therapy. Our results also demonstrated that blocking the HSP27 and HSP72 gene expression might serve as a therapeutic target for the human brain cancer.

Simultaneous determination of imperatorin and its metabolite xanthotoxol in rat plasma by using HPLC-ESI-MS coupled with hollow fiber liquid phase microextraction

The objective of the present study was to develop a new method for the simultaneous quantitation of imperatorin and its metabolite xanthotoxol in rat plasma. The samples were prepared with hollow fiber liquid phase microextraction (HF-LPME). The optimized extraction procedure was acquired by assessing extraction solvent, length of the fiber, agitation rate, extraction temperature and time. A comparison of sample pretreatment ways between HF-LPME and deproteinization with methanol was performed, which demonstrated less ion suppression and better sensitivity of HF-LPME. Analytes were separated on a C18 column with a gradient elution consisted of methanol and water containing 1mmol/L ammonium acetate. The detection was accomplished by electrospray ionization (ESI) source operating in the positive ionization mode. Selected-multiple-reaction monitoring (SMRM) scanning was employed, which guaranteed a higher sensitivity compared with MRM mode. Calibration curves were linear over investigated ranges with correlation coefficients greater than 0.9979. Precision varied from 0.26% to 14%, and the accuracy varied within ±5.5%. The developed method was successfully applied to the pharmacokinetic research of imperatorin and its metabolite xanthotoxol after oral administration of imperatorin to rats.

Effect of oral imperatorin on memory in mice

The aim of this study was to explore the effect of the acetylcholinesterase inhibiting mixture of extracts of Angelica archangelica fruit and Geranium sylvaticum on memory. Furthermore the effect of the main compound, the furanocoumarin imperatorin, which has been shown to affect several neurotransmitters, was studied. Passive avoidance was measured by step-down latency and step-through latency of 10 months old mice receiving 0.79 mg/kg of imperatorin daily, pure or as part of the extracts, for 14 days or longer. Step-down latency was significantly higher in both groups receiving imperatorin than in the control group. In contrast, no difference was found between treatment groups regarding step-through latency. The results indicate that the imperatorin is the main active component of the extract mixture.

Suppression of voltage-gated Na(+) channels and neuronal excitability by imperatorin

Imperatorin is a naturally occurring furocoumarin compound isolated from plants such as Angelica archangelica and Cnidium monnieri. It has multiple pharmacological effects including anticonvulsant effects. Here we determined the effects of imperatorin on voltage-gated Na(+) channels (VGSC) using whole-cell patch clamp techniques in differentiated neuronal NG108-15 cells. We showed that imperatorin inhibited VGSC; such inhibition did not show state-dependence. Imperatorin caused a left shift in the steady-state inactivation curve without affecting activation gating. The inhibition of VGSC by imperatorin displayed a mild frequency-dependence. Imperatorin was also shown to inhibit VGSC and action potential amplitude without affecting voltage-gated K(+) channels in rat hippocampal CA1 neurons. In conclusion, our results suggest that imperatorin dampens neuronal excitability by inhibiting VGSC.

Traditional Chinese medicine for the treatment of primary dysmenorrhea: how do Yuanhu painkillers effectively treat dysmenorrhea?

AIM

To examine the efficacy of YuanHu painkillers (YHP) as a treatment for primary dysmenorrhea and to reveal YHP's principle formula.

METHODS

A Wistar rat uterine contraction model was utilized in this study. Rats were given 0.698g/kg YHP, 0.07g/kg tetrahydropalmatine (THP; YHP's main component), 0.02g/kg imperatorin (IMP), or THP+IMP (0.07+0.02g/kg) as polypharmacy (PG) by gavage. H&E staining and histopathological examination of the uteri tissue samples were performed. We then detected superoxide dismutase (SOD) and malondialdehyde (MDA), nitric oxide (NO), as well as inducible nitric oxide synthase (iNOS), i-κB, nuclear factor-κB (NF-κB), and cyclooxygenase-2 (COX-2) indices.

RESULTS

PG significantly inhibited the uterine contraction of the primary dysmenorrhea rat model (p<0.05), and was significantly different than single-agent therapy (p<0.05). Histopathological examination showed inflammation in the uteri of the control group which YHP and its main constitutes alleviated. THP significantly inhibited the contraction of isolated uteri caused by Ach, PGF2α and oxytocin in a concentration-dependent fashion. THP and IMP both significantly affected the levels of NO, activation of NF-κB, up-regulated the expression of i-κB and down-regulated the expression of both iNOS and COX-2. IMP obviously decreased the level of MDA and increased the activation of SOD (p<0.05). PG obviously improved all the parameters mentioned above (p<0.05).

CONCLUSIONS

YHP exerted protective effects on primary dysmenorrhea in rats and remarkably alleviated the severity of experimental primary dysmenorrhea. The combined strategy proved to be more effective than either THP or IMP alone and may have synergistic effects in combination in primary dysmenorrhea. Mechanisms that might account for the beneficial effects include abating oxidative stress, inhibiting over-inflammatory reaction, and alleviating the contraction of isolated rat uteri by inhibiting the influx of extracellular Ca(2+). Broad potential for future clinical practice is foreseeable.

Effects of imperatorin on nicotine-induced anxiety- and memory-related responses and oxidative stress in mice

The purpose of the reported experiments was to examine the effects of imperatorin [9-[(3-methylbut-2-en-1-yl)oxy]-7H-furo[3,2-g]chromen-7-one] on anxiety and memory-related responses induced by nicotine in mice and their relation to the level of nicotine-induced oxidative stress in brain as well as in the hippocampus and the prefrontal cortex. Male Swiss mice were tested for anxiety in the elevated plus maze test (EPM), and for cognition using passive avoidance (PA) procedures. Imperatorin, purified by high-speed counter-current chromatography from methanol extract of fruits of Angelica officinalis, acutely administered at the doses of 10 and 20mg/kg impaired the anxiogenic effect of nicotine (0.1mg/kg, s.c.). Furthermore, acute injections of subthreshold dose of imperatorin (1mg/kg, i.p.) improved processes of memory acquisition when co-administered with nicotine used at non-active dose of 0.05 mg/kg, s.c. Additionally, repeated administration of imperatorin (1mg/kg, i.p., twice daily, for 6 days) improved different stages of memory processes (both acquisition and consolidation) when injected in combination with non-active dose of nicotine (0.05 mg/kg, s.c.) in the PA task. Oxidative stress was assessed by determination of antioxidant enzymes (glutathione peroxidases (GPx), superoxide dismutase (SOD), glutathione reductase (GR)) activities as well as of malondialdehyde (MDA) concentration in the whole brain, the hippocampus and the prefrontal cortex after repeated administration of imperatorin (1mg/kg, 6 days) and single nicotine injection (0.05 mg/kgs.c.) on the seventh day. The results of our research suggest strong behavioural interaction between imperatorin and nicotine at the level of anxiety- and cognitive-like processes. Furthermore, imperatorin inhibited nicotine-induced changes in examined indicators of oxidative stress, especially in the hippocampus and the cortex.