Five new sesquiterpenoids isolated from Dictamnus dasycarpus Turcz.

Five new sesquiterpenoids, dictamtrinorguaianols E and F (1-2), and dictameudesmnosides F, G, and H (3-5), along with seven known sesquiterpenoids (6-12) were isolated from Dictamnus dasycarpus Turcz. The structures of all new compounds were characterized by spectroscopic methods, including UV, IR, HR-ESI-MS, and 1D and 2D NMR. The In-vitro anti-proliferative activities of all the compounds against two human cancer cell lines (SW982 and A549) were evaluated by CCK-8 assay. Compounds 1 and 4 showed medium anti-proliferative activity against SW982 cells, with IC50 values of 3.49 ± 0.10 and 6.42 ± 1.23 µM, respectively. Additionally, compounds 2, 7, and 8 exhibited medium anti-proliferative activity against A549 cells, with IC50 values ranging from 0.80 ± 0.05 to 6.60 ± 0.46 µM.

Exploring the Mechanism of Hepatotoxicity Induced by Dictamnus dasycarpus Based on Network Pharmacology, Molecular Docking and Experimental Pharmacology.

The root bark of Dictamnus dasycarpus Turcz is a traditional Chinese medicine, Dictamni Cortex (DC), which is mainly used in the clinical treatment of skin inflammation, eczema, rubella, rheumatism, and gynecological inflammation. Unexpectedly, there are some cases of liver injury after the administration of DC. However, the mechanism of hepatotoxicity remains ambiguous. The aim of this study was to explore the mechanism and substance bases of DC hepatotoxicity based on network pharmacology and molecular docking, verified through pharmacological experiments. Partial prototype components and metabolites in vivo of quinoline alkaloids from DC were selected as candidate compounds, whose targets were collected from databases. Network pharmacology was applied to study the potential hepatotoxic mechanism after correlating the targets of candidate compounds with the targets of hepatotoxicity. Molecular docking was simulated to uncover the molecular mechanism. Furthermore, the hepatotoxicity of the extract and its constituents from DC was evaluated in vivo and in vitro. We constructed the "potential toxic components-toxic target-toxic pathway" network. Our results showed that the targets of DC included CYP1A2 and GSR, participating in heterologous steroid metabolism, REDOX metabolism, drug metabolism, heterocyclic metabolic processes, the synthesis of steroid hormone, cytochrome P450 metabolism, chemical carcinogens and bile secretion pathways. In vitro and in vivo experiments displayed that DC could result in a decrease in GSH-Px and oxidative stress, simultaneously inhibiting the expression of CYP1A2 and inducing hepatotoxicity. These results further indicated the mechanism of hepatotoxicity induced by Dictamnus dasycarpus, providing a basic theory to explore and prevent hepatotoxicity in the clinical usage of Dictamnus dasycarpus.

Undescribed protolimonoids from the root bark of Dictamnus dasycarpus Turcz.

Nine undescribed protolimonoids, including two apotirucallane and seven tirucallane triterpenoids, as well as five known compounds, were isolated from the root bark of Dictamnus dasycarpus Turcz. Their structures were elucidated by extensive spectroscopic analysis. Compounds 4-8, with an undescribed 22,25-epoxytirucallene part, were established their absolute configuration by single-crystal X-ray diffraction of 4. Such compounds might provide evidence for the degradation of protolimonoids to limonoids, bridging an oxidative cleavage biogenetic pathway between these structurally diverse triterpenoids. None of them showed anti-inflammatory, hepatoprotective, or monoamine oxidase B inhibitory activity.

The protein adduction derived from reactive metabolites of multiple furanoids in cortex Dictamni-treated mice.

The association of herb medicine Cortex Dictamni (CD) with severe even fatal hepatotoxicity has been widely reported. Recently, we demonstrated that the metabolic activation of at least ten furanoids in CD was responsible for the liver injury caused by the ethanol extract of CD (ECD) in mice. Protein adduction by reactive metabolites is considered to initiate the process of liver injury. Unlike single chemicals, the mode of and the details of protein modification by multiple components in an herb is unclear. This study aimed to characterize protein adductions derived from the reactive metabolite of furanoids in ECD-treated mice and define the association of protein adduction with liver injury. The hepatic cysteine- and lysine-based protein adducts derived from epoxide or cis-enedione of at least six furanoids were identified in mice. The furanoids with an earlier serum content Tmax were mainly to bind with hepatic glutathione and no protein adducts were formed except for dictamnine. The hepatic proteins were modified by the later absorbed furanoids. The levels of hepatic protein adduct were correlated with the degree of liver injury. In addition, the reactive metabolites of different furanoids can simultaneously bind to the model peptide by the identical reactive moiety, indicating the additive effects of the individual furanoids in the modification of hepatic proteins. In conclusion, hepatic protein adduction by multiple furanoids may play a role in ECD-induced liver injury. The earlier absorbed furanoids were mainly to bind with glutathione whereas the hepatic proteins were modified by the later furanoids.

Antimicrobial alkaloids from the root bark of Dictamnus dasycarpus.

Two new furoquinoline alkaloids, named 1'-oxo-isoplatydesmine (1) and demethoxyacrophylline (2), as well as 11 known alkaloids (3-13) were isolated from the root bark of Dictamnus dasycarpus Turcz. The structures of 1 and 2 were established by detailed spectroscopic elucidation, such as 1 D & 2 D NMR and HRMS, etc. The unexpected autoracemization of 1 was discussed based on the stereochemistry of reported dihydrofuroquinolines. Compounds 3-5 exhibited moderate inhibitory activities against Bacillus subtilis, Candida albicans, and Pseudomonas aeruginosa with MICs 32-64 µg/ml, revealing the active principles of D. dasycarpus for treating skin diseases in its traditional usage.

The traditional uses, phytochemistry, pharmacology and toxicology of Dictamnus dasycarpus: a review.

OBJECTIVES: Dictamnus dasycarpus is a plant of the Rutaceae family, and its root bark is the main part used as a medicine, named 'Bai-Xian-Pi'. It is used to clear away heat, remove dampness, and dispel wind and also used for detoxification. The purpose of this review is to provide a systematic review about the botany, traditional uses, phytochemistry, pharmacology and toxicology of this plant. KEY FINDINGS: More than 200 compounds have been isolated and identified from the plant, including alkaloids and their glycosides, terpenoids and their derivatives and phenylpropanoids. Extensive pharmacological activities of the extracts or compounds of D. dasycarpus in vivo and in vitro were mainly confirmed, including anti-inflammatory activity, protecting cardiovascular activity, improving liver injury and anti-cancer activity. SUMMARY: In this paper, the botany, traditional uses, phytochemistry and pharmacology of D. dasycarpus were reviewed. In the future, D. dasycarpus needs further study, such as paying more attention to quality control and the utilization on agriculture. In addition, discussing the medicinal components of decoction as well as the toxicity will also contribute to the progress of clinical trial studies.

[Network pharmacology study on potential active components in volatile oil of Dictamni Cortex].

There are many chemical components in the volatile oil of Dictamni Cortex. The complex network relationship of "component-target-disease" can be revealed by using the network pharmacology method, and the mechanism of the efficacy of Dictamni Cortex can be revealed. In this study, we used Swiss Target Prediction database to predict the target of action, STRING database to build protein interaction network, and Cytoscape software to build "component-target-disease" network. The results showed that the antibacterial, anti-inflammatory and antiallergic effects of Dictamni Cortex were closely related to the components of thymol methyl ether, elemenol, anethole, and the related targets of each component were cross-linked to play a multi-target pharmacodynamic role. This study laid a foundation for the study of the effective substance basis and quality control evaluation of the Dictamni Cortex, and provided a scientific basis for further revealing its mechanism.

Network pharmacology study on potential active components in volatile oil of Dictamni Cortex / 中国中药杂志

There are many chemical components in the volatile oil of Dictamni Cortex. The complex network relationship of "component-target-disease" can be revealed by using the network pharmacology method, and the mechanism of the efficacy of Dictamni Cortex can be revealed. In this study, we used Swiss Target Prediction database to predict the target of action, STRING database to build protein interaction network, and Cytoscape software to build "component-target-disease" network. The results showed that the antibacterial, anti-inflammatory and antiallergic effects of Dictamni Cortex were closely related to the components of thymol methyl ether, elemenol, anethole, and the related targets of each component were cross-linked to play a multi-target pharmacodynamic role. This study laid a foundation for the study of the effective substance basis and quality control evaluation of the Dictamni Cortex, and provided a scientific basis for further revealing its mechanism.

Isoprenoids obtained from Cortex Dictamni and their nitric oxide inhibitory activities.

Nine new isoprenoids, named as dictamtrinor-guaianols A (1), B (2), C (3), D (4), and E (5), dictamnorsesquiterpenol A (6), dictamnorsesquiterpenosides B (7) and C (8), as well as dictamtriterpenol A (9), along with eight known compounds (10-17) were obtained from 70% EtOH extract of Cortex Dictamni. Their structures were ascertained based on the extensive spectroscopic methods and ECD data analysis. Moreover, LC-MS analysis result suggested compounds 2 and 3 were natural products. Furthermore, lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage model were used to evaluate nitric oxide production inhibitory activities of them, and compounds 2, 3, 5, 6, 8-11, as well as 15-17 displayed significant activities at 40 µM.

[Analysis of epidemiological characteristics of drug induced liver injury associated with Baixianpi Preparations].

A retrospective study was performed in drug-induced liver injury(DILI) cases associated with Dictamni Cortex(Baixianpi,BXP) Preparations,which were treated at grade Ⅲ class A liver disease hospitals from 2008 to 2016 and spontaneously reported for adverse reactions between 2012 and 2016 at HILI Cloud(hilicloud.net). The results showed 25 DLII cases associated with BXP Preparations treated at grade Ⅲ class A liver disease hospitals during the 9 years,including only 14 cases in line with the clinical diagnostic criteria of Guidelines for the Diagnosis and Treatment of Herb-Induced Liver Injury. And 74 DILI cases associated with BXP Preparations spontaneously reports adverse reactions,and 18. 92% of them had unreasonable medication,including polypharmacy(21. 43%),overdose(28. 57%) and repeated dosage(50%). And 47 DILI cases used BXP Preparations to treat psoriasis and vitiligo(a total of59. 57%). The time range of taking BXP Preparations until liver injury occurred was 1-366 d,with the median of 18 d. The dose of BXP Preparations was estimated to be 0. 09-12 g·d-1. And the cumulative dosage of taking drugs until liver injury occurred was 1. 1-336 g. Obvious associations with time-toxicity as well as quantity-toxicity could not be found based on the wide range of time-toxicity relations and quantity-toxicity relations. On the basis of the study,we found that DILI cases associated with BXP Preparations commonly occurred in patients with immune diseases,such as psoriasis and vitiligo,indicating specific individual differences. The results suggested that DILI cases associated with BXP Preparations would be correlated with the property of idiosyncratic drug-induced liver injury. In conclusion,the risk of liver injury clinically caused by BXP Preparations should be paid more attention,and the studies on the mechanism of idiosyncratic drug-induced liver injury must be enhanced,and those on risk factors,like irrational drug use,should be strengthened. Moreover,the evaluation of the risk-to-benefit ratio is supposed to be performed for the sake of improving the risk prevention and control standards for BXP preparations,and ensuring safe and rational clinical application of BXP Preparations.

Anti-inflammatory constituents from Cortex Dictamni.

Eight new compounds named as dictamalkosides A (1), B (2), C (3), dictamphenosides A (4), B (5), C (6), D (7) and E (8), as well as 23 known ones were obtained from the 70% EtOH extract of Cortex Dictamni. Their structures were ascertained based on the spectroscopic evidences. Among the known compounds, 14, 17-23, 25-28, and 31 were isolated from Dictamnus genus for the first time; 16 and 24 were firstly isolated from this plant. And the 13C NMR data of 14 was reported here for the first time. Moreover, compounds 1-8, 12, 18-21, 27 and 31 were found to exhibit potential inhibitory effect on LPS-induced NO production at 40 µM for RAW 264.7 macrophages, which suggested alkaloids and phenolic acids might be anti-inflammation therapeutic substance in Cortex Dictamni.

[Mass spectrometry guided strategy based on feature fragment ions for guided-separation on quinoline alkaloids from root barks of Dictamnus dasycarpus].

The root bark of Dictamnus dasycarpus is one of common traditional Chinese medicines (TCMs). Quinoline alkaloids are one of the main active substances in this TCM and possess many biological activities including anti-titumor, anti-inflammation, anti-bacteria, anti-oxidation, and anti-platelet aggregation activities. In this study, eight quinoline alkaloids 1-8 were firstly separated from the root barks of D. dasycarpus. It was difficult to isolate more quinoline alkaloids from the remaining fraction 8 in D. dasycarpus by this conventional chemical separation, so the target analysis method combined LC-MS guided-separation of quinoline alkaloids from fraction 8 was established. MS/MS fragmentation patterns of eight quinoline alkaloids reference standard compounds 1-8 were studied by ultra-performance liquid chromatography-electrospary ionization-mass spectrometry (UPLC-ESI-MS/MS). Based on the feature fragment ion m/z 200, the parent ion scan mode was established for the target analysis of quinoline alkaloids in fraction 8. Finally, 8-methoxyflindersine (9) and N-metilatanina (10) were discovered and isolated quickly from fraction 8 guided by LC-MS, and their structures were identified by NMR and MS. Among them, compound 10 was isolated from the genus Dictamnus for the first time. These results indicated that this method is not only quick and sensitive for analyzing the quinoline alkaloids, but also to effectively guided-separate this kind of alkaloids in the root barks of D. dasycarpus.

Subchronic Toxicity Studies of Cortex Dictamni Extracts in Mice and Its Potential Hepatotoxicity Mechanisms in Vitro.

Cortex Dictamni is a commonly-used traditional Chinese herbal medicine for the treatment of skin inflammation, tinea, and eczema. Recently, some studies reported that Cortex Dictamni might induce liver injury, suggesting more attention to its safety. The current study was designed to investigate subchronic toxicity of Cortex Dictamni aqueous extract (CDAE) and ethanol extract (CDEE) in mice and the potential hepatotoxicity mechanisms in vitro. Firstly, CDAE or CDEE groups were administrated with varying dosages (2.3, 4.6, or 9.2 g/kg/day, p.o.) in mice for 28 days in subchronic toxicity studies. General clinical signs and biochemical parameters were examined, and morphological analyses were conducted. Secondly, we identified the different constituents of CDAE and CDEE using HPLC-MS/MS and chose major components for further study. In order to determine the toxic components, we investigated the cytotoxicity of extracts and chosen components using CCK-8 assay in HepG2 cells. Furthermore, we explored the possible hepatotoxicity mechanisms of Cortex Dictamni using a high content analysis (HCA). The results showed that no significant differences of general clinical signs were observed in mice. Aspartate alanine aminotransferase (ALT) and aminotransferase (AST) were significantly increased in the high-dose CDAE and CDEE groups compared to the control group. Meanwhile, the absolute and relative liver weights and liver/brain ratio were significantly elevated, and histological examination of liver demonstrated cellular enlargement or nuclear shrinkage. In UPLC analysis, we compared the chemical constituents between CDAE and CDEE, and chose dictamnine, obakunone, and fraxinellone for hepatotoxicity evaluation in the in vitro studies. In the CCK-8 assay, CDAE, CDEE, dictamnine, obakunone, and fraxinellone decreased the cell viability in a dose-dependent manner after treatment for 48 h. Furthermore, the cell number decreased, while the nuclear intensity, cell membrane permeability, and concentration of reactive oxygen species were shown to increase, meanwhile, mitochondrial membrane potential was also changed in HepG2 cells following 48 h of compounds treatment using HCA. Our studies suggested that CDAE and CDEE have potential hepatotoxicity, and that the alcohol extraction process could increase toxicity. Dictamnine, obakunone, and fraxinellone may be the possible toxic components in Cortex Dictamni with dictamnine as the most potentially hepatotoxic component, whose potential hepatotoxicity mechanism may be associated with cell apoptosis. Moreover, this study could provide valuable data for clinical drug safety research of Cortex Dictamni and a good example for safety study of other Chinese herbal medicines.

Dictamnine promotes apoptosis and inhibits epithelial-mesenchymal transition, migration, invasion and proliferation by downregulating the HIF-1α and Slug signaling pathways.

Dictamnine (DTM) is a natural alkaloid isolated from the root of Dictamnus dasycarpus Turcz and has been shown to exhibit multiple biological functions, including anti-inflammatory, antifungal, anti-angiogenic and anticancer activity. However, the mechanisms by which dictamnine inhibits tumor growth are not fully understood. In this study, we investigated the effectiveness of dictamnine as a treatment for cancer and to identify the underlying mechanisms of its anticancer activity. Here, dictamnine showed the potent inhibitory activity against HIF-1α and Slug activation induced by hypoxia in various human cancer cell lines. This compound markedly decreased the hypoxia-induced accumulation of HIF-1α and Slug protein in a dose-dependent manner. Further analysis revealed that dictamnine inhibited HIF-1α protein synthesis, without affecting its degradation. Our results demonstrated that dictamnine reduced HIF-1α protein synthesis by downregulating the mTOR/p70S6K/eIF4E and MAPK pathways, and reduced the expression of Slug by inhibiting the GSK-3ß/Slug signaling pathway. Moreover, epithelial-mesenchymal transition (EMT) was inhibited in dictamnine-treated tumors by downregulation of HIF-1α and Slug, as reflected by the upregulation of E-cadherin and Occludin, and the downregulation of N-cadherin and Vimentin. Phenomenological experiments showed that dictamnine reduced migration and invasion, inhibited HCT116 cell proliferation and promoted HCT116 cell apoptosis by downregulating HIF-1α and Slug. In vivo studies further confirmed that dictamnine treatment caused significant inhibition of tumor growth in a xenograft tumor model. These findings suggest that dictamnine is a potent cancer inhibitor, providing a rationale for anticancer pathway-targeted therapy.

The inhibitory effect of kokusaginine on the growth of human breast cancer cells and MDR-resistant cells is mediated by the inhibition of tubulin assembly.

The emergence of multidrug resistance (MDR) is a significant challenge in breast carcinoma chemotherapy. Kokusaginine isolated from Dictamnus dasycarpus Turcz. has been reported to show cytotoxicity in several human cancer cell lines including breast cancer cells MCF-7. In this study, kokusaginine showed the potent inhibitory effect on MCF-7 multidrug resistant subline MCF-7/ADR and MDA-MB-231 multidrug resistant subline MDA-MB-231/ADR. Kokusaginine markedly induced apoptosis in a concentration-dependent manner in MCF-7/ADR cells. Furthermore, kokusaginine reduced P-gp mRNA and protein levels, and suppressed P-gp function especially in MCF-7/ADR cells. In addition, kokusaginine showed to inhibit tubulin assembly and the binding of colchicine to tubulin by binding directly to tubulin and affects tubulin formation in vitro. Taken together, these results support the potential therapeutic value of kokusaginine as an anti-MDR agent in chemotherapy for breast carcinoma.

Eudesmane-Type Sesquiterpene Glycosides from Dictamnus dasycarpus Turcz.

Eudesmane-type sesquiterpenes have been reported to exhibit varieties of biological activities. During the process of investigating this kind of natural product from the root bark of Dictamnus dasycarpus Turcz., 13 eudesmane-type sesquiterpene glycosides including six new isolates, named as dictameudesmnosides A1 (1), A2 (2), B (3), C (4), D (5), and E (6), together with seven known ones (7-13), were obtained. Herein, their structures were determined by the analysis of physical data, spectroscopic analysis, and chemical methods. The existence of α-configuration glucose units in their structures (1-5, 8) is not very common in natural glycosidic components. Meanwhile, compounds 3-5, 7, and 9-13 displayed TG accumulation inhibitory effects on HepG2 cells.

Cortex Dictamni extracts inhibit over-proliferation and migration of rat airway smooth muscle cells via FAK/p38/Bcl-2 signaling pathway.

Airway smooth muscle (ASM) is a prominent effecter in maintaining bronchial muscle contraction and responsible for airway hyper-responsiveness (AHR); the phenotype change and over-proliferation of airway smooth muscle cells (ASMCs) play key roles in the pathogenesis of asthma. The aim of this study was to investigate the anti-proliferation effects of Cortex Dictamni aqueous extract (CDAE) and ethanol extract (CDE) on ASMCs and the possible underline mechanisms. Cell proliferation rates were determined by MTT assay; matrix metalloproteinases-2 (MMP-2) activity was examined by gelatin zymography; cell proliferation and migration were appraised by in-vitro cell-gap closure assessment; protein expressions of p38, Bcl-2 and FAK of ASMCs were evaluated by western blotting and Ca2+ influx of cells was measured by confocal laser microscope. Our data demonstrated that the proliferation, migration and MMP-2 expressions of ASMCs were inhibited by CDAE or CDE; the protein expressions of p38, Bcl-2 and FAK in ASMCs were substantially reduced by CDAE and CDE detected by western blotting or immunocytochemistry; also the increased calcium influx has been observed instantaneously after ASMCs were stimulated by CDAE or CDE. These findings suggested that Cortex Dictamni extracts might have inhibitory effects on ASMCs over-proliferation which could be one of the underline mechanisms for the therapy of asthma.

In vitro and in vivo antioxidative and hepatoprotective activity of aqueous extract of Cortex Dictamni.

AIM: To investigate the antioxidant and hepatoprotective effects of Cortex Dictamni aqueous extract (CDAE) in carbon tetrachloride (CCl4)-induced liver damage in rats. METHODS: The in vitro antioxidant effect of CDAE was investigated using α,α-diphenyl-ß-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), ß-carotene bleaching, reducing power, and thiobarbituric acid reactive substance assays. A linoleic acid system, including ferric thiocyanate (FTC) and thiobarbituric acid (TBA) assays, was used to evaluate the inhibition of lipid peroxidation. The in vivo hepatoprotective and antioxidant effects of CDAE against CCl4-induced liver damage were evaluated in Sprague-Dawley rats. Silymarin was used as a positive control. Liver damage was assessed by determining hepatic histopathology and liver marker enzymes in serum. Enzyme and non-enzyme antioxidant levels and lipid peroxide content were measured in the liver. Cytochrome P450 2E1 (CYP2E1) protein expression was measured via immunohistochemical staining. Nuclear factor E2-related factor (Nrf2), heme oxygenase-1 (HO-1), NAD(P)H quinine oxidoreductase 1 (NQO1), and γ-glutamylcysteine synthetase catalytic subunit (γ-GCSc) protein expression was measured by Western blot. RESULTS: Our results showed that CDAE exhibited a strong antioxidant activity in vitro. CDAE scavenged DPPH and ABTS radicals in a dose-dependent manner. CDAE inhibited lipid peroxidation with a lipid peroxide inhibition rate of 40.6% ± 5.2%. In the FTC and TBA assays, CDAE significantly inhibited lipid peroxidation (P < 0.01). In vivo histopathological studies indicated that CCl4-induced liver injury was alleviated following CDAE treatment in rats of both sexes. CDAE (160 and 320 mg/kg) significantly prevented CCl4-induced elevations of alkaline phosphatase, glutamate pyruvate transaminase, aspartate aminotransferase, and total bilirubin levels in rats of both sexes (P < 0.05, 0.01, or 0.001). Moreover, CDAE restored the decreased activities of hepatic antioxidant enzymes, including superoxide dismutase, catalase, and glutathione peroxidase, as well as non-enzyme antioxidant glutathione, which were induced by CCl4 treatment. CDAE significantly suppressed the up-regulation of CYP2E1 and promoted Nrf2, HO-1, NQO1, and γ-GCSc protein expression. CONCLUSION: CDAE exhibits good antioxidant performance in vitro, with marked radical-scavenging and anti-lipid peroxidation activities. CDAE is effective in preventing CCl4-induced hepatic damage in rats of both sexes. The hepatoprotective activity of CDAE may be attributable to its antioxidant activity, which may involve Keap1-Nrf2-mediated antioxidant regulation.

Rapid identification and global characterization of multiple constituents from the essential oil of Cortex Dictamni based on GC-MS.

The root of Dictamnus dasycarpus Turcz., also known as Cortex Dictamni, is a Chinese herbal medicine that has been commonly used in the treatment of inflammation, microbial infection, cancer, and other diseases in China for thousands of years. Recently, the essential oil of Cortex Dictamni has been widely studied, and a large number of volatile constituents have been discovered. However, the research of the essential oil of Cortex Dictamni in vivo remains unknown, especially the constituents absorbed into blood after oral administration. Hence, a sensitive and rapid method using gas chromatography with mass spectrometry combined with MassHunter software and the National Institute of Standards and Technology 2014 database was used to investigate the absorbed components in rat serum after oral administration of the essential oil of Cortex Dictamni. With the established method, a total of 36 compounds were screened and identified in the essential oil of Cortex Dictamni based on the mass spectrometry data and compound database. Among them, eight compounds, elemol, thymol methyl ether, ß-eudesmol, ß-cyclocostunolid, guaiazulene, trans-4-hydroxystilbene, ethyl oleate, and monoelaidin, were tentatively characterized in rat serum. This work demonstrated that the established method proved to be a powerful technique for rapid, simple, reliable, and automated identification of bioactive components of herbal medicine.

Radicol, a Novel Trinorguaiane-Type Sesquiterpene, Induces Temozolomide-Resistant Glioma Cell Apoptosis via ER Stress and Akt/mTOR Pathway Blockade.

Glioblastoma multiforme (GBM) is the most frequent, lethal and aggressive tumour of the central nervous system (CNS) in adults. Multidrug resistance (MDR) results in undesirable prognosis during GBM chemotherapy. In this study, we determined that Radicol (RAD), a novel trinorguaiane-type sesquiterpene originally isolated from the root of Dictamnus radicis Cortex, exhibited potently cytotoxic effect on temozolomide (TMZ)-resistant GBM cell lines in a dose-dependent manner. Radicol-induced apoptosis was confirmed with Hoechst 33342/propidium iodide and terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end-labelling (TUNEL) staining. Studies investigating the mechanism revealed that RAD triggered an attenuation of protein disulphide isomerase (PDI) and induced the unmitigated unfolded protein response (UPR) and lethal endoplasmic reticulum (ER) stress. Simultaneously, we further demonstrated that RAD suppressed the activation of Akt/mTOR/p70S6K phosphorylation by up-regulating the induction of glycogen synthase kinase-3ß (GSK-3ß). These results established a link between RAD-induced ER stress and inhibition of the Akt/mTOR/p70S6K pathway, and the attenuation of PDI and activation of GSK-3ß might be the synergistic target of antineoplastic effects during RAD-induced apoptosis. These findings suggested that RAD, possessing multiple cytotoxicity targets, low molecular weight and high lipid solubility, could be a promising agent for the treatment of malignant gliomas. Copyright © 2017 John Wiley & Sons, Ltd.