Research Progress on Chemical Constituents and Pharmacological Activities of Menispermi Rhizoma.

Menispermi Rhizoma, the rhizome of Menispermum dauricum DC., is a traditional Chinese medicine, which has the effect of clearing away heat and detoxification, dispelling wind, and relieving pain. It is often used in the treatment of sore throat, enteritis, dysentery, and rheumatism. The chemical constituents of M. Rhizoma mainly include alkaloids, phenolic acids, quinones, cardiotonic glycosides, and so on. Modern pharmacological studies have proved that M. Rhizoma has the effects of anti-tumour, anti-inflammation, anti-oxidation, bacteriostasis, cardio-cerebrovascular protection, anti-depression and anti-Alzheimer's disease. In recent years, the chemical constituents of M. Rhizoma have been found continuously, and the pharmacological studies have deepened gradually. This paper reviews the research progress on the chemical composition and pharmacological effects of M. Rhizoma, to provide a basis for further research and development of its medicinal value.

A novel oxoisoaporphine-type alkaloid from the rhizome of Menispermum dauricum.

A phytochemical investigation of Menispermum dauricum led to the isolation of five oxoisoaporphine-type alkaloids (1-5) and five aporphine-type alkaloids (6-10), including a novel oxoisoaporphine-type alkaloid: menispeimin A (1). Their structures were elucidated by spectroscopic studies including MS, 1 D and 2 D NMR, and confirmed by comparing with literature data. Among them, alkaloids 4-10 were obtained for the first time from Menispermum genus. Natural products 2, 4 and 6 exhibited significant cytotoxic activity against A549, Bel-7402 and MCF-7 cell lines.

Gas chromatography (GC) fingerprinting and immunomodulatory activity of polysaccharide from the rhizome of Menispermum dauricum DC.

This research aimed to establish the gas chromatography (GC) fingerprints and examine the immunomodulatory activity of the rhizome of Menispermum dauricum polysaccharides. In this study, the preparation conditions were optimized by the response surface method (RSM). GC is an effective and sensitive technique employed to measure the composition of monosaccharides; the GC fingerprints of total polysaccharides from 10 batches of the rhizome of M. dauricum (tMDP) were established, and chemometrics methods were adopted to examine the differences and similarities of tMDP from distinct regions. The similarity evaluation illustrated that the polysaccharides derived from the rhizome of M. dauricum from different origins were highly similar. The results of principal components analysis (PCA) illustrated that all the tMDPs may be integrated into one group within the 95% confidence interval, but the rhizome of M. dauricum from different origins could also be distinguished in the plot of PCA scores. Then, the major bioactive fraction MDP was purified and obtained by column chromatography. Our previous study showed that MDP exhibited significant immunomodulatory activity, but the mechanism of the in vitro immunomodulatory activity of MDP is unclear. The macrophage activation induced by MDP was abolished when Toll-like receptor 4 (TLR4) signaling was knocked down by the TLR4 inhibitor. Furthermore, western blot analysis illustrated that MDP activated RAW264.7 cells through MAPKs and NFκB pathways induced by TLR4. This research offers a theoretical foundation for quality control and additional study as a potential immunomodulator of MDP.

Menisperdaurines A-W, structurally diverse isoquinoline alkaloids from Menispermum dauricum and their dopamine D1 receptor activities.

A total of 33 structurally diverse isoquinoline alkaloids were isolated from the rhizomes of Menispermum dauricum, including seventeen benzylisoquinoline analogues (menisperdaurines A-Q, 1-17), five protoberberine analogues (menisperdaurines R-V, 18-22), a quaternary phenanthrene alkaloid (menisperdaurine W, 23) and ten known compounds (24-33). Compound structures, including absolute configurations, were determined by extensive spectroscopic methods, quantum chemical calculations of chemical shifts, and calculated and experimental electronic circular dichroism (ECD) data. Compounds 1-5 were glycosidic benzylisoquinolines with glucose moieties attached at the C-12 position. Compound 8 was the first example that was isolated from the rhizomes of Menispermum dauricum, benzylisoquinoline and an aromatic unit connected by a sugar bridge. Compounds were evaluated for their inhibitory effects on the dopamine D1 receptor. Compounds 1, 8, 21, 24 and 29 showed potent D1 antagonistic activities, with IC50 values ranging from 1.0 to 4.5 µM. Compound 1 exhibited the highest antagonistic activity with an IC50 value of 1.0 ± 0.2 µM.

Isoquinoline alkaloid dimers with dopamine D1 receptor activities from Menispermum dauricum DC.

A phytochemical investigation on chemical constituents from the rhizomes of Menispermum dauricum DC. identified eight undescribed dimeric alkaloids with structurally diverse monomeric isoquinoline. Alkaloid structures were elucidated by a combination of spectroscopic data analyses and time-dependent density functional theory (TDDFT) ECD calculation. The isolates were evaluated for inhibitory effect on dopamine D1 receptor and compound 1 exhibited potent D1 receptor antagonistic activity with an IC50 value of 8.4 ± 2.0 µM.

Analgesic bisbenzylisoquinoline alkaloids from the rhizoma of Menispermum dauricum DC.

Fifteen new bisbenzylisoquinoline alkaloids (1-15) were isolated from the rhizome of Menispermum dauricum DC. Compounds 1-9 were new N-oxides of dauricine-type alkaloids. Compounds 10-14 were rare tail-to-tail quaternary alkaloids. Their structures were characterized by comprehensive analysis of spectroscopic data, and absolute configurations were established from electronic circular dichroism (ECD) data and ECD calculations. Compounds were assayed on analgesic-related G-protein coupled receptors (GPCRs) including dopamine D1 and D2 receptors, opioid Mu receptor and muscarinic M3 receptor. Compound 1 showed high affinity and selective antagonistic activity on the M3 receptor with an IC50 value of 2.2 ± 0.5 µM; compound 15 exhibited the highest antagonistic affinity among the evaluated compounds on Mu (IC50 = 1.1 ± 0.6 µM) and it also acted as a D1 receptor antagonist (IC50 = 8.8 ± 2.9 µM). These findings expanded the existing library of bisbenzylisoquinoline alkaloids and provided new structures for the related future drug design and synthesis.

Pharmacokinetics, tissue distribution and excretion of 6-O-demethylmenisporphine, a bioactive oxoisoaporphine alkaloid from Menispermi Rhizoma, as determined by a HPLC-MS/MS method.

6-O-demethylmenisporphine, a major active oxoisoaporphine alkaloid isolated from Menispermi Rhizoma, has been confirmed to possess significant bioactivities, including anti-cancer and anti-hypoxia effects. However, few researches on quantifying 6-O-demethylmenisporphine in biosamples have been performed. In this research, a sensitive HPLC-MS/MS approach for determining 6-O-demethylmenisporphine in various biological matrices (plasma, tissue, urine, bile and feces) of rat has been constructed. Carbamazepine was chosen as the internal standard (IS). All biosamples were prepared using a simple one-step acetonitrile precipitation. A Capcell Pak C18 column coupled with an isocratic mobile phase consisted of acetonitrile (0.1% formic acid)-water (90:10, v/v), was employed to separate 6-O-demethylmenisporphine from endogenous interferences. Peak responses were detected by multiple reaction monitoring (MRM) transitions with m/z 308.0 â†’ 264.9 for 6-O-demethylmenisporphine and m/z 237.0 â†’ 194.1 for IS in positive-ion mode. The approach exhibited perfect linearity over a range of 5-2000 ng/mL for plasma and 2-1000 ng/mL for various tissue, urine, bile and feces. The lower limit of quantification (LLOQ) for analyte among different biological samples ranged from 2 ng/mL to 5 ng/mL. The newly established method was simple, efficient and sensitive, which was successfully applied to investigate the absorption, distribution, and excretion of 6-O-demethylmenisporphine after oral dosing to rats. The results indicated that 6-O-demethylmenisporphine could be well absorbed into blood circulation and widely distributed in various tissues after oral dosing, the oral bioavailability was up to 51.52%. Meanwhile, it was widely metabolized in vivo and eliminated as the metabolites, the unconverted form was excreted mainly by feces route. The bioavailability, tissue distribution and excretion characteristics of 6-O-demethylmenisporphine were firstly revealed, which will provide references for further development of 6-O-demethylmenisporphine as an anti-tumor drug candidate.

Anti-tumor effects of phenolic alkaloids of menispermum dauricum on gastric cancer in vivo and in vitro.

AIM: This study was conducted to investigate the anti-tumor effects of the Chinese traditional herb phenolic alkaloids of menispermum dauricum (PAMD) on gastric cancer both in vitro and in vivo. MATERIALS AND METHODS: Cell apoptosis was detected in cultured SGC-7901 cells after administration of a different dose of PAMD. Gastric cancer model was established by single i.p. injection of SGC-7901 cells in the mice (n = 60). Then, animals were received high dose (20 mg/kg), medial dose (10 mg/kg), and low dose (5 mg/kg) of PAMD. Mice received 5-floxuridine was set as positive controls and received normal saline was as blank controls. Effects of PAMD on tumor growth were evaluated by tumor inhibition rate. Tumor tissues were collected from mice and detected for the expression of several genes P53, B-cell CLL/lymphoma 2 (BCL-2), BCL-2-associated X protein (BAX), CASPASE-3, K-RAS by real-time polymerase chain reaction, and Western blot. In addition, tumor cell changes were observed under transmission electron microscopy. RESULTS: The apoptosis index in PAMD at high- and medial-dose group was significantly higher than that in blank control group (P < 0.01). PAMD at different dose could significantly decrease the tumor weight compared to the blank control group (P < 0.01). In addition, PAMD could obviously increase BAX and caspase-3 expression as well as decrease K-RAS expression when compared to the blank control treatment (P < 0.01). Furthermore, PAMD could induce tumor cell morphology changes. CONCLUSIONS: PAMD could suppress gastric tumor growth in vivo, possibly through increasing the expression of pro-apoptotic genes expression then leading to cell apoptosis and inhibiting oncogenic K-RAS expression.

Dauricine combined with clindamycin inhibits severe pneumonia co-infected by influenza virus H5N1 and Streptococcus pneumoniae in vitro and in vivo through NF-κB signaling pathway.

Dauricine, isolated from Menispermum dauricum, has been widely used for treatment of various diseases, including cardiac ischemia and inflammation-related diseases. However, little is known regarding to the effect of dauricine on severe pneumonia. Therefore, the aim was to investigate the effect of dauricine on severe pneumonia and its mechanism during progress. Herein, H5N1 and Streptococcus pneumoniae (D39) were conducted to induce severe pneumonia in both BEAS-2B cells and mice. In vitro, dauricine reversed the protein and mRNA expressions of TNF-α, IL-6 and IL-1ß, examined by ELISA and qRT-PCR assay, respectively. In addition, the nuclear translocation of NF-κB/p65 and the phosphorylation expressions of IκBα and IKKα/ß, examined by western blotting, were dose-dependently dropped by dauricine. However, dauricine had no significant effect on MAPKs, including JNK, ERK and p38. In vivo, dauricine significantly decreased MPO activity, the lung wet/dry weight ratio, the protein and mRNA expression of TNF-α, IL-6 and IL-1ß, the expressions of NF-κB/p65, and attenuated the lung histological alterations. Besides, compared to dauricine alone, combined with clindamycin had more remarkably effects on severe pneumonia in vitro. Overall, the results suggested that dauricine, a relatively drug that targets NF-κB, in combination with clindamycin, maybe a novel therapeutic strategy for severe pneumonia.

Intestinal anti-inflammatory effect of the rhizome extracts of Menispermum dauricum DC. on trinitrobenzene sulfonic acid induced ulcerative colitis in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Menispermum dauricum DC., commonly known as "Bei Dou Gen" (BDG) in China, has been used extensively in folk medicine to treat inflammatory diseases, especially intestinal inflammations such as enteritis and dysentery, and in pharyngitis, tonsillitis, rheumatism and bronchitis. Although previous studies showed that BDG has anti-inflammatory activities, its effects on ulcerative colitis (UC) have not yet been explored. AIM OF THE STUDY: To investigate the intestinal anti-inflammatory effect of the rhizome extracts of Menispermum dauricum DC. on UC model induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS) in mice. MATERIALS AND METHODS: UC in mice was induced by colonic administration with TNBS. BDG (100, 200 and 400mg/kg/day) and sulfasalazine (500mg/kg/day) were administered orally for 7 consecutive days. The inflammatory degree was assessed by gross appearance, macroscopic and histological analysis, and accumulation of myeloperoxidase (MPO) activity. Pro-inflammatory mediators, including tumor necrosis factor (TNF)-α, interleukin (IL)-1ß and IL-6, were determined by enzyme-linked immunoassay. The expression of cyclooxygenase (COX)-2 was assessed by immunohistochemical analysis. RESULTS: Treatment with different doses of BDG significantly ameliorated macroscopic damage and histological changes, reduced the accumulation of MPO activity, depressed serum and colonic tissue levels of TNF-α, IL-1ß and IL-6 in a dose-dependent manner. In addition, administration of BDG effectively reduced COX-2 overexpression in colon. CONCLUSION: We demonstrated for the first time that BDG possessed marked intestinal anti-inflammatory effect in TNBS induced colitis in mice, which might be related to the reduction of up-regulated productions and expressions of pro-inflammatory mediators, suggesting that it may have beneficial use for the treatment of inflammatory bowel disease.

Microwave-assisted extraction in combination with HPLC-UV for quantitative analysis of six bioactive oxoisoaporphine alkaloids in Menispermum dauricum DC.

A novel and reliable method based on microwave-assisted extraction (MAE) followed by HPLC-UV was developed and validated for the simultaneous quantification of six pharmacologically important oxoisoaporphine alkaloids in the total plants of Menispermum dauricum DC. The optimal MAE extraction condition was performed at 60°C for 11 min with ethanol-water (70:30, v/v) as the extracting solvent, and the solvent to solid ratio was 20:1. Chromatographic separation was achieved on a reversed-phase YMC C18 column (250 × 4.6 mm, i.d., 5 µm) with a gradient mobile phase consisting of A (1% aqueous formic acid) and B (acetonitrile containing 1% formic acid) at a flow rate of 1.5 mL/min. The detection wavelength was set at 422 nm. Excellent linearity over the investigated concentration ranges was observed with values of r >0.999 for all analytes. The method developed was validated with acceptable sensitivity, intra- and inter-day precision and extraction recoveries. It was successfully applied to the determination of six alkaloids in Menispermum dauricum DC from different sources and different parts of Menispermum dauricum DC. The results obtained indicated that the method is suitable for the quality control of Menispermum dauricum DC.

Rapid determination of eight oxoisoaporphine alkaloids in Rhizoma Menispermi by the optimal homogenate extraction followed by UPLC-MS/MS.

The objective of this study was to develop a rapid and reliable homogenate extraction (HGE) and ultra high-performance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) method for simultaneous analysis of eight bioactive oxoisoaporphine alkaloids (including two new alkaloids) in Rhizoma Menispermi. HGE was optimized by response surface methodology (RSM) to obtain the maximum extraction efficiency of eight alkaloids. Separation was achieved on a Waters ACQUITY UPLC® BEH C18 column (50 × 2.1 mm(2), 1.7 µm) using gradient elution with a mobile phase consisting of acetonitrile and 0.2% formic acid in water. Quantification was performed with multiple reaction monitoring (MRM) mode using positive ESI as an interface. This is the first report of the simultaneous analysis of eight oxoisoaporphine alkaloids in Rhizoma Menispermi using a UPLC-MS/MS method; this analysis afforded good linearity, precision, and accuracy. Then, the method was successfully applied to determine the alkaloids in Rhizoma Menispermi from different sources.

Identification of nuclear factor-κB inhibitors in the folk herb Rhizoma Menispermi via bioactivity-based ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry analysis.

BACKGROUND: Rhizoma Menispermi (RM) is the dried root of Menispermum dauricum DC, which is traditionally used to treat swelling and pain for sore throat, enteritis and rheumatic arthralgia in the clinic, but its bioactive compounds remain unclear. METHODS: In this study, RM extract was administered orally to ICR mice followed by challenging with an intratracheal Pseudomonas aeruginosa suspension. Then mortality, histological features of lung, and inflammatory cytokines were evaluated. RM treatment significantly ameliorated Pseudomonas aeruginosa-induced acute lung inflammation and reduced levels of inflammatory mediators. To screen for potential anti-inflammatory constituents of the RM extract, a simple and rapid method based on ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF MS) coupled with a luciferase reporter assay system to detect nuclear factor-κB (NF-κB) activity was established. RESULTS: Using this system, seven potential NF-κB inhibitors were detected, including sinomenine, norsinoacutin, N-norsinoacutin-ß-D-glucopyranoside, 6-O-methyl-laudanosoline-13-O-glucopyranoside, magnoflorine, laurifloline and dauricinoline. Furthermore, IL-6 and IL-8 assays confirmed the anti-inflammatory effects of these potential NF-κB inhibitors, in which norsinoacutin, 6-O-methyl-laudanosoline-13-O-glucopyranoside laurifloline, dauricinoline and N-norsinoacutin-ß-D-glucopyranoside were revealed as new NF-κB inhibitors. CONCLUSION: This method of UPLC-Q/TOF coupled with the luciferase reporter assay system was initially applied to the study of RM and was demonstrated to represent a simple, rapid and practical approach to screen for anti-inflammatory compounds. This study provided useful results for further investigation on the anti-inflammatory mechanism of RM.

Induction of apoptosis in human cervical carcinoma Hela cells with active components of Menispermum dauricum.

Menispermum dauricum DC possesses a wide range of pharmacological effects. In this study, the mechanism of apoptosis induced by active components of M. dauricum was investigated in the human cervical carcinoma HeLa cell line. HeLa cells were treated with different M. dauricum concentrations over different time periods. The proliferation-inhibitory rate and cytotoxic effect of HeLa cells were measured by using the methyl thiazolyl tetrazolium (MTT) assay, and the apoptotic rate was detected by flow cytometry. Expressions of caspase-9, caspase-8, caspase-3, Bcl-2, and Fas proteins, in the apoptotic pathway, and the expression of nuclear factor-kappa B (NF-κB) were detected by SP immunocytochemistry. The MTT assay showed that active components of M. dauricum could significantly inhibit the growth of HeLa cells in a dose- and time-dependent manner (P<0.01). The Sub-Gl peak was found by flow cytometry, and the maximal apoptosis rate was 24.93%. Immunocytochemistry showed that after treatment with M. dauricum, the expressions of caspase-8, caspase-9, caspase-3, Fas protein, and NF-κB all increased, and the expression of the Bcl-2 protein decreased, with significant differences relative to the control group (P<0.01). Apoptosis in HeLa cells could be induced by active components of M. dauricum through the NF-κB signal transduction pathway and the caspase pathway, which was related to the downregulation of Bcl-2 expression and the upregulation of Fas expression.

P­glycoprotein inhibition increases the transport of dauricine across the blood­brain barrier.

Dauricine is the major bioactive component isolated from the roots of Menispermum dauricum D.C. The aim of the present study was to investigate the role of P­glycoprotein in the transport of dauricine across the blood­brain barrier by pre­treatment with the P­glycoprotein inhibitor verapamil. Sprague Dawley rats were divided into a verapamil group (pretreated with verapamil at a dose of 20 mg/kg) and a control group (pretreated with the same volume of normal saline). After 90 min, the animals were injected intravenously with dauricine (10 mg/kg). At 15, 30 and 60 min after dauricine administration, the levels of dauricine in the blood and brain were detected by high­performance liquid chromatography. Compared with the control group, the dauricine concentration in the brains of the rats in the verapamil group was significantly increased. Furthermore, the brain­plasma ratio of dauricine in the rats pretreated with verapamil was significantly higher than that of the animals in the control group. However, there was no difference identified between dauricine levels in the plasma of the verapamil and the control groups. The results indicated that dauricine is able to pass the blood­brain barrier, and that P­glycoprotein has an important role in the transportation of dauricine across the blood­brain barrier.

Inhibitory effects of phenolic alkaloids of Menispermum dauricum on gastric cancer in vivo.

The present study was conducted to investigate effects and mechanisms of action of phenolic alkaloids of Menispermum dauricum (PAMD) on gastric cancer in vivo. In vitro, cell apoptosis of human gastric cancer cell line SGC-7901 was observed using fluorescence staining. In vivo, a mice model was constructed to observe tumor growth with different doses. Cell apoptosis was examined using flow cytometry and K-RAS protein expression using Western blotting. The mRNA expression of P53, BCL-2, BAX, CASPASE-3, K-RAS was examined by real-time PCR. PAMD significantly suppressed tumor growth in the xenograft model of gastric cancer in a dose- dependent manner (p<0.01). Functionally, PAMD promoted cell apoptosis of the SGC-7901 cells and significantly increased the rate of cell apoptosis of gastric tumor cells (p<0.05). Mechanically, PAMD inhibited the expression of oncogenic K-RAS both at the mRNA and protein levels. In addition, PAMD affected the mRNA expression of the cell apoptosis-related genes (P53, BCL-2, BAX, CASPASE-3). PAMD could suppress gastric tumor growth in vivo, possibly through inhibiting oncogenic K-RAS, and induce cell apoptosis possibly by targeting the cell apoptosis-related genes of P53, BCL-2, BAX, CASPASE-3.

Anti-ovarian cancer potential of two acidic polysaccharides from the rhizoma of Menispermum dauricum.

Two acidic polysaccharides (MDP-A1 and MDP-A2) were isolated from the rhizome of Menispermum dauricum and their apparent molecular weight are 9.1×10(4) and 5.8×10(4) Da, respectively. Both contained glucose, mannose, galactose, arabinose, glucuronic acid and galacturonic acid, but differed in the molar ratio. We also investigated the antitumor activities and mechanisms of MDP-A1 and MDP-A2 in human ovarian carcinoma SKOV3 cells. The MTT assay showed that MDP-A1 and MDP-A2 were able to inhibit cell proliferation of SKOV3 cells in a bell-shaped concentration-response manner, due to a significant increase in the number of apoptotic cells. Furthermore, treatment with MDP-A1 or MDP-A2 caused significant induction of caspase-3 and caspase-8, but slightly affected caspase-9 activity. In addition, a significant reduction in tumor volume was observed in mice treated with MDP-A1 or MDP-A2. Taken together, these results suggested that MDP-A1 and MDP-A2 had a potential application as natural antitumor drugs.

Characterization and antitumor activities of a polysaccharide from the rhizoma of Menispermum dauricum.

The rhizome of Menispermum dauricum DC (Menispermaceae) is one of the most commonly used traditional Chinese medicines officially listed in Chinese Pharmacopeia. In present study, we purified a water-soluble polysaccharide (WMDP) from this plant and investigated its physicochemical properties. WMDP was a homogeneous polysaccharide, with an average molecular weight of approximately 3.5×10(4)Da, as determined by high-performance gel-permeation chromatography (HPGPC). Gas chromatography (GC) analysis identified that WMDP was composed of Glc, Gal, Xyl, Rha, Ara and Man in the ratio of 2.45:2.13:1.05:1.29:1.63:1.45. The interreaction between Gongo Red and WMDP in NaOH solutions resulted in the shift of maximum absorption, indicating WMDP had a triple-helix conformation. We also investigated the antitumor activities and mechanisms of WMDP in human ovarian carcinoma SKOV3 cells. The experimental evidence showed that WMDP significantly inhibited cell proliferation and DNA synthesis in SKOV3 cells in a concentration-dependent manner, due to a significant increase in the number of apoptotic cells. Furthermore, treatment with WMDP caused a rapid loss of intracellular glutathione (GSH) content and stimulation of reactive oxygen species (ROS). In addition, nuclear factor-kappa B (NF-κB) in SKOV3 cells received WMDP treatment was inactivated. Taken together, induction of apoptosis on SKOV3 cells by WMDP was mainly associated with ROS production, GSH depletion and NF-κB inactivation.

Dauricine can inhibit the activity of proliferation of urinary tract tumor cells.

OBJECTIVE: To explore the anti-tumor effects of asiatic moonseed rhizome extraction-dauricine on bladder cancer EJ cell strain, prostate cancer PC-3Mcell strain and primary cell culture system. METHODS: The main effective component-phenolic alkaloids ofMenispermum dauricum was extracted and separated from asiatic moonseed rhizome by chemical method. MTT method was used to detect dauricine anti-tumor effect. RESULTS: Dauricine had an obvious proliferation inhibition effect on the main tumor cells in urinary system. The minimum drug sensitivity concentration was between 3.81-5.15 µg/mL, and the inhibition ratio increased with the increase of concentration. CONCLUSIONS: Dauricine, the main effective component extracted from asiatic moonseed rhizome, had a good inhibition effect on tumor cells in urinary system. At the same time, Dauricine has certain inhibition effects on the primary cultured tumor cell.

Effect of daurisoline on HERG channel electrophysiological function and protein expression.

Daurisoline (1) is a bis-benzylisoquinoline alkaloid isolated from the rhizomes of Menispermum dauricum. The antiarrhythmic effect of 1 has been demonstrated in different experimental animals. In previous studies, daurisoline (1) prolonged action potential duration (APD) in a normal use-dependent manner. However, the electrophysiological mechanisms for 1-induced prolongation of APD have not been documented. In the present study, the direct effect of 1 was investigated on the hERG current and the expression of mRNA and protein in human embryonic kidney 293 (HEK293) cells stably expressing the hERG channel. It was shown that 1 inhibits hERG current in a concentration- and voltage-dependent manner. In the presence of 10 µM 1, steady-state inactivation of V(1/2) was shifted negatively by 15.9 mV, and 1 accelerated the onset of inactivation. Blockade of hERG channels was dependent on channel opening. The expression and function of hERG were unchanged by 1 at 1 and 10 µM, while hERG expression and the hERG current were decreased significantly by 1 at 30 µM. These results indicate that 1, at concentrations below 30 µM, exerts a blocking effect on hERG, but does not affect the expression and function of the hERG channel. This may explain the relatively lower risk of long QT syndrome after long-term usage.