Integrated metabolomic and transcriptomic analyses provide insights into regulation mechanisms during bulbous stem development in the Chinese medicinal herb plant, Stephania kwangsiensis.

BACKGROUND: Stephania kwangsiensis Lo (Menispermaceae) is a well-known Chinese herbal medicine, and its bulbous stems are used medicinally. The storage stem of S. kwangsiensis originated from the hypocotyls. To date, there are no reports on the growth and development of S. kwangsiensis storage stems. RESULTS: The bulbous stem of S. kwangsiensis, the starch diameter was larger at the stable expanding stage (S3T) than at the unexpanded stage (S1T) or the rapidly expanding stage (S2T) at the three different time points. We used ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and Illumina sequencing to identify key genes involved in bulbous stem development. A large number of differentially accumulated metabolites (DAMs) and differentially expressed genes (DEGs) were identified. Based on the differential expression profiles of the metabolites, alkaloids, lipids, and phenolic acids were the top three differentially expressed classes. Compared with S2T, significant changes in plant signal transduction and isoquinoline alkaloid biosynthesis pathways occurred at both the transcriptional and metabolic levels in S1T. In S2T compared with S3T, several metabolites involved in tyrosine metabolism were decreased. Temporal analysis of S1T to S3T indicated the downregulation of phenylpropanoid biosynthesis, including lignin biosynthesis. The annotation of key pathways showed an up-down trend for genes and metabolites involved in isoquinoline alkaloid biosynthesis, whereas phenylpropanoid biosynthesis was not completely consistent. CONCLUSIONS: Downregulation of the phenylpropanoid biosynthesis pathway may be the result of carbon flow into alkaloid synthesis and storage of lipids and starch during the development of S. kwangsiensis bulbous stems. A decrease in the number of metabolites involved in tyrosine metabolism may also lead to a decrease in the upstream substrates of phenylpropane biosynthesis. Downregulation of lignin synthesis during phenylpropanoid biosynthesis may loosen restrictions on bulbous stem expansion. This study provides the first comprehensive analysis of the metabolome and transcriptome profiles of S. kwangsiensis bulbous stems. These data provide guidance for the cultivation, breeding, and harvesting of S. kwangsiensis.

1H NMR-guided isolation of hasubanan alkaloids from the alkaloidal extract of Stephania longa.

1H NMR-guided fractionation led to the isolation of 16 alkaloids from the alkaloidal extract of Stephania longa, including 11 new hasubanan alkaloids (1-11) and five known alkaloids (12-16). Interestingly, compounds 2 and 11 are typically considered protonated tertiary amine compounds, whereas compounds 1 and 10 are regarded as oxidized versions of the corresponding compounds. Their gross structures were determined through an extensive analysis of spectroscopic data (NMR (nuclear magnetic resonance) and HRESIMS (high resolution electrospray ionization mass spectroscopy)), and their absolute configurations were established by comparing their experimental and calculated electronic circular dichroism (ECD) spectra. The new (3) and a known (12) compounds in all isolates displayed stronger antineuroinflammatory effects (IC50 values of 1.8 and 11.1 µM, respectively) than minocycline (IC50 value of 15.5 µM) against NO production on LPS-activated BV2 cells.

Modulation of in Vitro SARS-CoV-2 Infection by Stephania tetrandra and Its Alkaloid Constituents.

Botanical natural products have been widely consumed for their purported usefulness against COVID-19. Here, six botanical species from multiple sources and 173 isolated natural product compounds were screened for blockade of wild-type (WT) SARS-CoV-2 infection in human 293T epithelial cells overexpressing ACE-2 and TMPRSS2 protease (293TAT). Antiviral activity was demonstrated by an extract from Stephania tetrandra. Extract fractionation, liquid chromatography-mass spectrometry (LC-MS), antiviral assays, and computational analyses revealed that the alkaloid fraction and purified alkaloids tetrandrine, fangchinoline, and cepharanthine inhibited WT SARS-CoV-2 infection. The alkaloids and alkaloid fraction also inhibited the delta variant of concern but not WT SARS-CoV-2 in VeroAT cells. Membrane permeability assays demonstrate that the alkaloids are biologically available, although fangchinoline showed lower permeability than tetrandrine. At high concentrations, the extract, alkaloid fractions, and pure alkaloids induced phospholipidosis in 293TAT cells and less so in VeroAT cells. Gene expression profiling during virus infection suggested that alkaloid fraction and tetrandrine displayed similar effects on cellular gene expression and pathways, while fangchinoline showed distinct effects on cells. Our study demonstrates a multifaceted approach to systematically investigate the diverse activities conferred by complex botanical mixtures, their cell-context specificity, and their pleiotropic effects on biological systems.

Stephtetrandrine A-D, bisbenzylisoquinoline alkaloids from Stephania tetrandra.

Four undescribed bisbenzylisoquinoline alkaloids, designated as Stephtetrandrine A-D, were isolated from the roots of Stephania tetrandra. Their structures were elucidated by IR, HRESIMS, ECD spectra, 1 D and 2 D NMR spectra and comparison with the literature data. Additional five known compounds (limacine, tetrandrine, N-trans-Feruloyltyramine, 2'-N-chloromethyltetrandrine, 2,2'-N-N-dichloromethyltetrandrine) were also isolated. N-trans-Feruloyltyramine was isolated from Stephania tetrandra for the first time. The isolated compounds were tested for monoamine oxidase, acetylcholinesterase, phosphoinositide 3-kinase α and human hepatoma cell HepG2 inhibitory activities. Stephtetrandrine C showed obvious inhibitory effect on human hepatoma HepG2, with IC50 value of 16.2 µM. Limacine and 2'-N-chloromethyltetrandrine showed moderate monoamine oxidase inhibitory effect with the IC50 values of 37.7 and 29.2 µM, respectively.

Evaluating cepharanthine analogues as natural drugs against SARS-CoV-2.

Cepharanthine (CEP) is a natural biscoclaurine alkaloid of plant origin and was recently demonstrated to have anti-severe acute respiratory syndrome coronavirus 2 (anti-SARS-CoV-2) activity. In this study, we evaluated whether natural analogues of CEP may act as potential anti-coronavirus disease 2019 drugs. A total of 24 compounds resembling CEP were extracted from the KNApSAcK database, and their binding affinities to target proteins, including the spike protein and main protease of SARS-CoV-2, NPC1 and TPC2 in humans, were predicted via molecular docking simulations. Selected analogues were further evaluated by a cell-based SARS-CoV-2 infection assay. In addition, the efficacies of CEP and its analogue tetrandrine were assessed. A comparison of the docking conformations of these compounds suggested that the diphenyl ester moiety of the molecules was a putative pharmacophore of the CEP analogues.

Identification of alkaloidal compounds from leaves and roots of Stephania succifera by HPLC-QTOF-MS and prediction of potential bioactivity with PharmMapper.

INTRODUCTION: The roots of Stephania succifera are used in traditional medicine for the treatment of several diseases. Research on this plant has mainly focused on bioactive alkaloids from the roots, and no previous work on compounds from the abundant leaves has yet been reported. OBJECTIVE: To identify and compare alkaloidal compounds in S. succifera roots and leaves and to predict the potential bioactivity of some alkaloids. METHODS: High-performance liquid chromatography with quadrupole time-of-flight tandem mass spectrometry (HPLC-QTOF-MS/MS) was employed to identify alkaloidal compounds from S. succifera. The potential targets and bioactivities of most alkaloids were predicted using the PharmMapper server. RESULTS: Fifty-six alkaloidal compounds, including protoberberine-, aporphine-, proaporphine-, benzylisoquinoline-, and lactam-type alkaloids, were identified or tentatively identified in S. succifera roots and leaves based on the HPLC-MS data. Forty-one compounds have not been previously reported in S. succifera and eight of them have not been previously reported in the literature. Twenty-four alkaloidal compounds were found in both roots and leaves. Twelve potential targets with different indications were predicted for some alkaloids. CONCLUSION: Comparison of chemical constituents and their potential bioactivities for S. succifera roots and leaves indicated that diverse bioactive alkaloids were present in the leaves as well as the roots. PharmMapper provided new directions for bioactivity screening. This study will be helpful for further understanding the medicinal components of S. succifera and the rational utilisation of plant resources.

Hasubanan alkaloids with anti-inflammatory activity from Stephania longa.

Two new hasubanan alkaloids, stephalonester A (1) and stephalonester B (2), together with four known compounds, stephalonine E (3), longanone (4), cephatonine (5), and prostephabyssine (6) were isolated from the whole plant of Stephania longa. Their structures were determined by HR-ESI-MS, 1 D and 2 D NMR, ECD calculations, as well as by comparison with literature values. All compounds were evaluated for their anti-inflammatory activity in vitro. Compounds 4, 5, and 6 exhibited significantly inhibitory effects on TNF-α and IL-6 production with IC50 values range from 6.54 to 30.44 µM.

Vasorelaxant-Mediated Antihypertensive Effect of the Leaf Aqueous Extract from Stephania abyssinica (Dillon & A. Rich) Walp (Menispermaceae) in Rat.

Stephania abyssinica is a medicinal plant used in Cameroon alternative medicine to treat arterial hypertension (AHT). Previous in vitro studies demonstrated the endothelium nitric oxide-independent vasorelaxant property of the aqueous extract from Stephania abyssinica (AESA). But its effect on AHT is unknown. The present study was undertaken to explore other vasorelaxant mechanisms and to determine the antihypertensive effects of AESA in male Wistar rats. Phytochemical analysis of AESA was carried out using the liquid chromatography-mass spectrometry (LC-MS) method. The vasorelaxant effects of AESA (1-1000 µg/mL) were studied on rat isolated thoracic aorta rings, in the absence or presence of indomethacin (10 µM) or methylene blue (10 µM). The inhibitory effect of AESA on phenylephrine (PE, 10 µM) or KCl- (60 mM) induced contraction as well as the intracellular calcium release was also evaluated. The in vivo antihypertensive activity of AESA (43, 86, or 172 mg/kg/day) or captopril (20 mg/kg/day) administered orally was assessed in L-NAME- (40 mg/kg/day) treated rats. Blood pressure and heart rate (HR) were measured at the end of each week while serum or urinary nitric oxide (NO), creatinine, and glomerular filtration rate (GFR) were determined at the end of the 6 weeks of treatment, as well as histological analysis of the heart and the kidney. The LC-MS profiling of AESA identified 9 compounds including 7 alkaloids. AESA produced a concentration-dependent relaxation on contraction induced either by PE and KCl, which was significantly reduced in endothelium-denuded vessels, as well as in vessels pretreated with indomethacin and methylene blue. Moreover, AESA inhibited the intracellular Ca2+ release-induced contraction. In vivo, AESA reduced the AHT, heart rate (HR), and ventricular hypertrophy and increased serum NO, urine creatinine, and GFR. AESA also ameliorated heart and kidney lesions as compared to the L-NAME group. These findings supported the use of AESA as a potential antihypertensive drug.

An extract of Stephania hernandifolia, an ethnomedicinal plant, inhibits herpes simplex virus 1 entry.

Stephania hernandifolia (Nimukho), an ethnomedicinal herb from rural Bengal, has been used traditionally for the management of nerve, skin, urinary, and digestive ailments. Here, we attempted to confirm the antiviral potential of aqueous, methanol, and chloroform extracts of S. hernandifolia against herpes simplex virus type 1 (HSV-1), the causative agent of orolabial herpes in humans, and decipher its underlying mechanism of action. The bioactive extract was standardized and characterized by gas chromatography-mass spectroscopy, while cytotoxicity and antiviral activity were evaluated by MTT and plaque reduction assay, respectively. Two HSV strains, HSV-1F and the clinical isolate VU-09, were inhibited by the chloroform extract (CE) with a median effective concentration (EC50) of 4.32 and 4.50 µg/ml respectively, with a selectivity index (SI) of 11. Time-of-addition assays showed that pre-treatment of virus-infected cells with the CE and its removal before infection reduced the number of plaques without lasting toxicity to the cell, indicating that the CE affected the early stage in the viral life cycle. The number of plaques was also reduced by direct inactivation of virions and by the addition of CE for a short time following attachment of virions. These results together suggest that modification of either the virion surface or the cell surface by the CE inhibits virus entry into the host cell.

Natural potential neuroinflammatory inhibitors from Stephania epigaea H.S. Lo.

Stephania epigaea H. S. Lo is a folk medicine widely distributed in the south of China, especially in Yunnan and Guangxi province. An in vitro anti-neuroinflammatory study showed that total alkaloids of it can potently inhibit LPS-induced NO releasing of BV2 cells with an IC50 value of 10.05 ± 2.03 µg/mL (minocycline as the positive drug, IC50 15.49 ± 2.14 µM). The phytochemical investigation of the total alkaloids afforded three new phenanthrene (1-3), two lactams (4a, 4b), and nine aporphine derivatives (5-13). The final structure of 1 was identified by computer-assisted structure elucidation (ACD/Structure Elucidator software and the 13C NMR calculation with GIAO method) due to many possibilities of the substituent pattern. All isolates were evaluated for their anti-neuroinflammatory effects, and as a result, 5, 8, 10, and 11 exhibited stronger inhibitory activities than the minocycline. The results suggested S. epigaea could provide potential therapeutic agents for neurodegenerative diseases.

Cytotoxic and Anti-Plasmodial Activities of Stephania dielsiana Y.C. Wu Extracts and the Isolated Compounds.

Natural products remain a viable source of novel therapeutics, and as detection and extraction techniques improve, we can identify more molecules from a broader set of plant tissues. The aim of this study was an investigation of the cytotoxic and anti-plasmodial activities of the methanol extract from Stephania dielsiana Y.C. Wu leaves and its isolated compounds. Our study led to the isolation of seven alkaloids, among which oxostephanine (1) is the most active against several cancer cell lines including HeLa, MDA-MB231, MDA-MB-468, MCF-7, and non-cancer cell lines, such as 184B5 and MCF10A, with IC50 values ranging from 1.66 to 4.35 µM. Morever, oxostephanine (1) is on average two-fold more active against cancer cells than stephanine (3), having a similar chemical structure. Cells treated with oxostephanine (1) are arrested at G2/M cell cycle, followed by the formation of aneuploidy and apoptotic cell death. The G2/M arrest appears to be due, at least in part, to the inactivation of Aurora kinases, which is implicated in the onset and progression of many forms of human cancer. An in-silico molecular modeling study suggests that oxostephanine (1) binds to the ATP binding pocket of Aurora kinases to inactivate their activities. Unlike oxostephanine (1), thailandine (2) is highly effective against only the triple-negative MDA-MB-468 breast cancer cells. However, it showed excellent selectivity against the cancer cell line when compared to its effects on non-cancer cells. Furthermore, thailandine (2) showed excellent anti-plasmodial activity against both chloroquine-susceptible 3D7 and chloroquine-resistant W2 Plasmodium falciparum strains. The structure-activity relationship of isolated compound was also discussed in this study. The results of this study support the traditional use of Stephania dielsiana Y.C. Wu and the lead molecules identified can be further optimized for the development of highly effective and safe anti-cancer and anti-plasmodial drugs.

In vitro inhibitory effects of cepharanthine on human liver cytochrome P450 enzymes.

Context: Cepharanthine (CEP) extracted from the roots of Stephania cepharantha Hayata (Menispermaceae), has a range of therapeutic potential in clinical conditions. Whether it affects the activity of human liver cytochrome P450 (CYP) enzymes remains unclear.Materials and methods: The effects of CEP (100 µM) on eight human liver CYP isoforms (i.e., 1A2, 3A4, 2A6, 2E1, 2D6, 2C9, 2C19 and 2C8) were investigated in vitro using human liver microsomes (HLMs) with specific probe actions and probe substrates. In addition, the enzyme kinetic parameters were calculated.Results: The results showed that the activity of CYP3A4, CYP2E1 and CYP2C9 was inhibited by CEP, with IC50 values of 16.29, 25.62 and 24.57 µM, respectively, but other CYP isoforms were not affected. Enzyme kinetic studies showed that CEP was not only a non-competitive inhibitor of CYP3A4 but also a competitive inhibitor of CYP2E1 and CYP2C9, with Ki values of 8.12, 11.78 and 13.06 µM, respectively. Additionally, CEP is a time-dependent inhibitor for CYP3A4 with KI/Kinact value of 10.84/0.058 min/µM.Discussion and conclusions: The in vitro studies of CEP with CYP isoforms indicate that CEP has the potential to cause pharmacokinetic drug interactions with other co-administered drugs metabolized by CYP3A4, CYP2E1 and CYP2C9. Further clinical studies are needed to evaluate the significance of this interaction.

Amide-Iminoate Isomerism in Antineuroinflammatory Isoquinoline Alkaloids from Stephania cepharantha.

Six new (1-6) and two known (7, 8) alkaloids that were chemically inseparable geometrical isomers (two isomers present in a 1:1 ratio for 1-4 and 6 and a 1:3 ratio for 5, 7, and 8) were identified from Stephania cepharantha. Their structures and absolute configurations were determined by spectroscopic data analyses and comparison of their experimental and calculated ECD spectra. Moreover, using NOE correlations and DFT-based calculations, the NMR data of each geometrical isomer of 1-6 were assigned. The biological evaluation of 1-8 showed that 5 and 6 have stronger inhibitory effects (IC50 values, 12.0 and 12.6 µM, respectively) than minocycline (IC50 value, 17.5 µM) against NO production in overactivated BV2 cells, suggesting they have great potential in the development of neuroinflammatory therapeutics for treating neurodegenerative diseases.

Differentiation, chemical profiles and quality evaluation of five medicinal Stephania species (Menispermaceae) through integrated DNA barcoding, HPLC-QTOF-MS/MS and UHPLC-DAD.

Stephania species is one of the alkaloid-rich genus of the family Menispermaceae. Most plants of the genus Stephania possess medicinal value, whose main components are alkaloids. However, the non-medical species are often mistakenly used as herbs because of the difficulty in identification of the species. A systematic method which involved the combination of DNA barcoding, HPLC-QTOF-MS/MS and UHPLC was established for differentiation, chemical profiles and quality evaluation of medicinal Stephania species. Firstly, twenty batches of Stephania species samples were classified into five Stephania species by DNA barcoding. Secondly, 114 alkaloids including 22 tetrahydroprotoberberines, 13 protoberberines, 27 aporphines, 13 benzylisoquinolines, 12 hasubanans, 3 morphines and 24 other alkaloids were clearly or tentatively identified. Thirdly, thirteen representative components were simultaneously detected by UHPLC-DAD to characterize the differences of chemical compositions among five Stephania species. In conclusion, this method was comprehensive and effective for identification, chemical profiles and quality evaluation of medicinal Stephania species. It will provide a basis for holistic quality evaluation of medicinal Stephania species.

Natural neuroprotective alkaloids from Stephania japonica (Thunb.) Miers.

Modulating inflammatory responses after stroke can prevent brain injury and, therefore, improve neurological outcome. Stephania japonica (Thunb.) Miers is a Chinese folk medicine with the function of dispelling the "wind and blockage" in the human body according to the Chinese medicine theory, in which the symptoms of stroke are caused by the "wind and blockage" in the body. In this paper, we for the first time linked S. japonica to stroke by clarifying fifteen alkaloidal constituents including five undescribed (1-5) ones and screening out six hasubanan type alkaloids (1-4, 7, 15) that elicited stronger anti-neuroinflammatory activities than the positive drug. Moreover, the total alkaloid fraction (ASJ) with previously undescribed 3 as the main component was subject to the in vivo evaluation of the protective effect in the MCAO-induced brain injury. The results showed that ASJ exhibited potent protective effect against brain injury in the MCAO rat model. The results reported in this paper suggested that the hasubanan alkaloids from S. japonica would be an important molecular source for discovering novel therapeutic agents for neuroinflammation-related diseases, such as stroke diseases.

Antibacterial activity of colistin is resurrected by Stephania suberosa Forman extract against colistin-resistant Enterobacter cloacae.

To resurrect antibacterial efficacy of colistin (CLT), ceftazidime (CAZ) and cefotaxime (CTX), Stephania suberosa extract (SSE) was combined with these particular antibiotics to combat CLT-resistant Enterobacter cloacae (CREC) isolates. Disc diffusion assay showed that SSE inhibited E. cloacae strains with the dose-dependent manner. Minimum inhibitory concentrations (MICs) of SSE against all tested strains were 2000 µg ml-1 . CREC DMST 37480 and 19719 were found to be resistant to CLT with MICs of 64 and 4 µg ml-1 , respectively, and also resistant to CAZ. These strains showed a minimum bactericidal concentration (MBC) of SSE at 8000 µg ml-1 . Checkerboard assay showed that CLT resistance was synergistically reversed by SSE against CREC DMST 37480 and 19719 with a fractional inhibitory concentration (FIC) indices of 0·253 and 0·265, respectively. Time-killing assay confirmed synergistic interaction by a decline in the viability combined treated group compared to an individual. CREC DMST 19719 was found to produce AmpC ß-lactamase. SSE cannot resurrect CAZ in an AmpC producer. The scanning electron microscopy showed that SSE and CLT induced cell damages at different sites. GC-MS analysis identified 25 known Phyto-compounds. SSE and CLT combination could be further developed as a novel agent for treating multidrug-resistant CREC. SIGNIFICANCE AND IMPACT OF THE STUDY: Resistance to colistin (CLT), an alternative agent for treating multiple drug-resistant Enterobacter cloacae, is among the most serious, life-threatening issues. This study utilizes Stephania suberosa extract (SSE) to revive the antibacterial activity of colistin that has lost its antibacterial effectiveness in inhibiting E. cloacae. The findings support the development of the combined agent between SSE and colistin to conquer colistin-resistant E. cloacae.

Cepharanthine: An update of its mode of action, pharmacological properties and medical applications.

BACKGROUND: Cepharanthine (CEP) is a drug used in Japan since the 1950s to treat a number of acute and chronic diseases, including treatment of leukopenia, snake bites, xerostomia and alopecia. It is the only approved drug for Human use in the large class of bisbenzylisoquinoline alkaloids. This natural product, mainly isolated from the plant Stephania cephalantha Hayata, exhibits multiple pharmacological properties including anti-oxidative, anti-inflammatory, immuno-regulatory, anti-cancer, anti-viral and anti-parasitic properties. PURPOSE: The mechanism of action of CEP is multifactorial. The drug exerts membrane effects (modulation of efflux pumps, membrane rigidification) as well as different intracellular and nuclear effects. CEP interferes with several metabolic axes, primarily with the AMP-activated protein kinase (AMPK) and NFκB signaling pathways. In particular, the anti-inflammatory effects of CEP rely on AMPK activation and NFκB inhibition. CONCLUSION: In this review, the historical discovery and development of CEP are retraced, and the key mediators involved in its mode of action are presented. The past, present, and future of CEP are recapitulated. This review also suggests new opportunities to extend the clinical applications of this well-tolerated old Japanese drug.

High Performance Liquid Chromatography Determination and Optimization of the Extraction Process for the Total Alkaloids from Traditional Herb Stephania cepharantha Hayata.

Stephania cepharantha Hayata is a traditional Chinese herbal medicine used to treat lung cancer, and its alkaloids, especially cepharanthine (CEP), were reported to be its effective ingredients. Therefore, the extraction of potential antitumor ingredients from the plant was of interest. We first explored the optimized solvent extraction of antitumor agents from S. cepharantha Hayata guided by an in vitro antitumor activity assay. The solvent for extraction and its concentration, the liquid to material ratio, extraction duration, particle size, macerating time, and the frequency of extraction were investigated using a single-factor experiment. An orthogonal design (L9, 34) was constructed to determine the suitable extraction conditions. The crude extract was then purified sequentially by macroporous adsorption resins (MR) for the enrichment of CEP. Under these optimal conditions, the yield of total alkaloids in the herbs was 3.4%, whereas the CEP content was 2.9%. Total alkaloids exhibited significant anti-proliferative activities in the A549 cell line. Our study provides means for the further development and use of the antitumor components from S. cepharantha, which has potential for application in the pharmaceutical industry.

Simultaneous determination of alkaloids dicentrine and sinomenine in Stephania epigeae by 1H NMR spectroscopy.

Stephania epigaea Lo is an important herbal medicine used as antiphlogistic and analgesic drugs. Its major components are dicentrine (1) and sinomenine (2). In the present study, a rapid, accurate, and precise method for simultaneous quantitation of dicentrine (1) and sinomenine (2) in S. epigeae using 1H NMR spectra was developed. The deuterated solvent of DMSO-d6 enabled satisfactory separation of the signals to be integrated in 1H NMR spectrum and dimethyl terephthalate was selected as an internal standard. The feature signals of δ 7.57 and 5.70 were selected for quantifying the dicentrine (1) and sinomenine (2), respectively. Validation of the quantitative method was performed in terms of specificity, accuracy, precision, and stability. This work implied that quantitative 1H NMR represents a feasible alternative to high-performance liquid chromatography-based methods for quantitation of dicentrine (1) and sinomenine (2) in S. epigeae and is suitable for the quality control of S. epigeae.

Total Synthesis of the Norhasubanan Alkaloid Stephadiamine.

(+)-Stephadiamine is an unusual alkaloid isolated from the vine Stephania japonica. It features a norhasubanan skeleton, and contains two adjacent α-tertiary amines, which renders it an attractive synthetic target. Here, we present the first total synthesis of stephadiamine, which hinges on an efficient cascade reaction to implement the aza[4.3.3]propellane core of the alkaloid. The α-aminolactone moiety in a highly hindered position was installed via Tollens reaction and Curtius rearrangement. Useful building blocks for the asymmetric synthesis of morphine and (nor)hasubanan alkaloids are introduced.