Target Alkaloids Research Articles

Improving the food safety of bakery products by simultaneously monitoring the occurrence of pyrrolizidine, tropane and opium alkaloids

The exponential number of food alerts about concerning levels of some plant-alkaloids, such as pyrrolizidine, tropane and opium alkaloids, have stressed the need to monitor their occurrence in foods to avoid toxic health effects derived from their intake. Therefore, analytical strategies to simultaneously monitor the occurrence of these alkaloids should be developed to ensure food safety an comply with regulations. Accordingly, this work proposes an efficient multicomponent analytical strategy for the simultaneous extraction of these alkaloids from commercial bakery products. The analytical method was validated and applied to the analysis of 15 samples, revealing that 100% of them contained at least one of the target alkaloids, in some cases exceeding the maximum limits legislated. Moreover, in two samples the 3 different alkaloid families were detected. These results confirm the importance of simultaneously monitoring these alkaloids in food and highlight also considering some opium alkaloids in current legislation.

Pattern Recognition of Alkaloids by Inhibiting the Catalytic Activity of Dopzymes for Dopamine.

Exploiting the specific recognition probe for all of the biomolecules is difficult in "lock-and-key" biosensors. The cross-reaction or the semispecific probe in pattern recognition mode is an alternative strategy through extracting a multidimensional signal array from recognition elements. Here, we design a pattern recognition sensor array based on the alkaloid-inhibited catalytic activity of dopzymes for the discrimination and determination of six alkaloids. In this sensor array, three different G-rich sequences, i.e., G-triplex (G3), G-quadruplex (GQ1), and the G-quadruplex dimer (2GQ1) possessing various peroxidase activities, conjugated with a dopamine aptamer and the dopzymes (G3-d-apt, GQ1-d-apt, and 2GQ1-d-apt) were obtained with an enhanced catalytic performance for the substrate. Through the interactions between six target alkaloids and G3, GQ1, and 2GQ1 regions, the pattern signal (6 alkaloids × 3 dopzymes × 5 replicates) was obtained from the diverse inhibited effect for the dopzyme activity. In virtue of the statistical method principal component analysis (PCA), the data array was projected into a new dimensional space to acquire the three-dimensional (3D) canonical scores and grouped into their respective clusters. The sensor array exhibited an outstanding discrimination and classification capability for six alkaloids with different concentrations with 100% accuracy. In addition, the nonspecific recognition elements of the sensor array showed high selectivity even though other alkaloids with similar structures to targets existed in the samples. Importantly, the levels of the six targets can be analyzed by the most influential discrimination factor, which represented the vector with the highest variance, evidencing that the sensor array has potential in drug screening and clinical treatment.

Testing for Kratom alkaloids in fingernail clippings – not only mitragynine

Kratom (Mitragyna speciosa) is a species of large tree that grows in Southeast Asia and is part of the Rubiaceae family. Its fresh leaves are harvested for their medicinal properties and used for their psychoactive effects. Kratom contains many biologically active alkaloids, including mitragynine and 7-OH-mitragynine, which are considered the two most important psychoactive components and constitute approximately 66% and 2% of the total alkaloid content. Other alkaloids are present in the plant, such as speciogynine, speciociliatine and paynantheine, but have less psychoactive activity. Over the past decade, the sale of kratom powder has increased on the Internet. This led to a significant increase in forensic cases. Given the lack of data existing in the literature, and the total absence of data in nails, the authors report a study to determine the best target alkaloids for documenting kratom consumption in this matrix. Fingernail clippings from a supposed kratom powder user were analyzed after liquid-liquid extraction, chromatography separation using a HSS C18 column and performed on an ultra-high performance liquid chromatography coupled to a tandem mass spectrometer. In the specimen, mitragynine was quantified at 229 pg/mg, speciogynine and paynantheine were both quantified at 2 pg/mg, and speciociliatine was quantified at 19 pg/mg. 7-OH-mitragynine was not detected. The interpretation of these concentrations is complex, since there is currently no reference in the literature, as this is the first identification of mitragynine and other kratom alkaloids in nails. Nevertheless, in view of the high concentration of mitragynine, the subject seems to be a repetitive user of kratom. According to the measured concentrations, it seems that mitragynine remains the best target to document kratom consumption, but the identification of the other alkaloids would enhance the specificity of the test.

Effect of silver nanoparticles on tropane alkaloid production of transgenic hairy root cultures of Hyoscyamus muticus L. and their antimicrobial activity

The utilization of nanotechnology and biotechnology for enhancing the synthesis of plant bioactive chemicals is becoming increasingly common. The hairy root culture technique can be used to increase secondary metabolites such as tropane alkaloids. Agrobacterium was used to induce hairy roots from various explants of Hyoscyamus muticus. The effect of nano-silver particles (AgNPs) at concentrations of 0, 25, 50, 100, and 200 mg/L on tropane alkaloids synthesis, particularly hyoscyamine and scopolamine, was studied in transgenic hairy root cultures. Different types of explants obtained from 10-day-old seedlings of H. muticus were inoculated with two strains of Agrobacterium rhizogenes (15,834 and A4). The antimicrobial activity of an ethanolic extract of AgNPs-induced hairy root cultures of H. muticus was tested. The frequency of hairy roots was higher in hypocotyl, root, leaf, and stem explants treated with A. rhizogenes strain A4 compared to those treated with strain 15,834. In transgenic hairy root cultures, AgNPs application at a concentration of 100 mg/L resulted in the highest total tropane alkaloid production, which exhibited broad-spectrum antimicrobial activity. The study demonstrated the potential of nano-silver as an elicitor for promoting the production of target alkaloids in Hyoscyamus muticus hairy root cultures, which exhibit high biological activity.

Resin adsorption as a means for the enrichment and separation of three terpenoid indole alkaloids: Vindoline, catharanthine and vinblastine from Catharanthus roseus extracts in ionic liquid solution

Simultaneous enrichment and separation of vindoline, catharanthine and vinblastine from Catharanthus roseus (Madagascar periwinkle) ionic liquid extracts was developed. To screen an appropriate resin, 12 commonly used macroporous resins were considered in terms of their performance and characteristics for adsorption and desorption of the target alkaloids . The adsorption capacity and desorption ratio of HPD750 resin for vindoline, catharanthine and vinblastine are found to be higher than that for the other resins, and, thus, this resin was chosen as the most suitable macroporous resin for the enrichment and separation of vindoline, catharanthine and vinblastine. The dynamic adsorption and desorption technical parameters of the target alkaloids were studied and optimized in an HPD750 resin-filled column. The optimum conditions for the adsorption process were determined to be as follows: vindoline, catharanthine and vinblastine loading concentrations in the sample solution of 10.22, 5.41 and 0.98 mg/L, respectively, sample volume of 45 mL, flow rate of 2 BV/h, and a temperature of 25 °C. For the desorption process, 5 BV of pure water was used to wash the impurities and ionic liquid, and then 10–80 % volume fraction of ethanol was used as the eluant (10–30 % volume fraction ethanol was used to remove impurities, and 40–80 % volume fraction ethanol was used to desorb and collect the target alkaloids as the final product). After enrichment and separation under these conditions, the vindoline, catharanthine and vinblastine contents in the products are determined to be 13.59 %, 7.42 % and 1.34 %, with recoveries of 71.37 %, 73.58 % and 75.00 %, respectively. In addition, the recycling of ionic liquid was attempted, which led to the achievement of better results. • Catharanthus roseus 1-allyl-3-methylimidazolium bromide extracts were considered. • C. roseus alkaloids adsorption/desorption performance of 12 resins were compared. • The static and dynamic tests on a non-ionic polymeric resin was investigated. • Macroporous resin was attempted for separation target analytes from AmimBr solution. • Resin HPD750 was the most suitable one from the testing of 12 types of resins.

Simultaneous Determination of Protoberberine Alkaloids Derived from Coptidis Rhizoma and Phellodendri Cortex in Pharmaceuticals by On-line Solid-Phase Extraction (SPE)—High Performance Liquid Chromatography with Ultraviolet Detection (HPLC-UV)

An automated on-line solid-phase extraction (SPE) high-performance liquid chromatography (HPLC) method was developed for the determination of six protoberberine alkaloids in compound Chinese medicines containing Coptidis Rhizoma and Phellodendri Cortex. The sample solution extracted by acidic-methanol was loaded into the constructed system directly to perform enrichment and the purification of the analytes was performed automatically. A cation-exchanged sorbent based on turbulent chromatography was employed for on-line SPE to remove macro and neutral matrix interferences from samples. The target alkaloids were retained on the SPE column and eluted onto the trapping C18 column by a mobile phase of methanol/500 mM ammonium acetate (85:15) at a flow rate of 0.3 mL/min. Ion pair reverse phase high-performance liquid chromatography was employed to complete the determination of six analytes. The results showed the linear correlation coefficients for all analytes were above 0.999. The peak area of relative standard deviation in reproducibility measurements were from 0.55% to 2.39%. Recovery measurements spiked at two levels were from 92.71% to 104.28%. The reported method was suitable for the determination of six active alkaloids in multicomponent Chinese medicines containing Coptidis rhizoma and Phellodendri cortex.

High‐performance counter‐current chromatography purification and off‐line mass spectrometry monitoring and identification of pyrrolizidine alkaloid markers of tropical Ghanaian honey

The nutritional and medicinal properties of honey have been well-documented. However, honey has occasionally been contaminated with hepatotoxic pyrrolizidine alkaloids as a result of bees foraging on the flowers of pyrrolizidine alkaloid plants. This study establishes a simple and rapid method to determine the marker pyrrolizidine alkaloids in honey using high-performance counter-current chromatography and an off-line electrospray ionization-tandem mass spectrometry, in order to identify the botanical sources responsible for the contamination. The honey sample was initially liquid-liquid extracted (sulfuric acid/hexane, 2:3, v/v) to enrich the pyrrolizidine alkaloids and subsequently purified by a semi-preparative high-performance counter-current chromatography using a solvent system, hexane/butanol/1% aqueous ammonia, 1:1:2, v/v, based on partition coefficient measurements of the target alkaloids. The recovered fractions were profiled by injecting them sequentially into an off-line electrospray ionization-tandem mass spectrometry device to monitor the preparative molecular weight based on elution and extrusion modes. The monitored lycopsamine-type pyrrolizidine alkaloids and their N-oxides (m/z 300, 316; lycopsamine, intermedine, rinderine, and echinatine) were used as the phytochemical markers to identify plants like Chromolaena odorata, Ageratum spp., or Heliotropium spp. to be responsible for the pyrrolizidine alkaloid contamination. Identification of these pyrrolizidine alkaloid plants could guide beekeepers in locating their beehives in order to minimize their potential liver damaging effects.

Quantification of Atropine and Scopolamine in Different Plant Organs of Datura Metel: Development and Validation of High-Performance Liquid Chromatography Method

Datura metel (Solanaceae) from south Lebanon. The different parts of this plant contain the tropane alkaloids atropine (AT) and scopolamine (SC), which are naturally muscarinic receptor antagonists. A method has been developed for the extraction and HPLC-UV analysis of the AT and SC in different parts of D. metel, namely seeds, capsule, leaf, and stem. This analytical method was validated and gave a good detection response with linearity over a dynamic range of 0.03‑0.17 mg mL−1 and recovery in the range of 93.9–108.76%. Limit of detection (LOD) and limit of quantification (LOQ) values were 32 and 98 µg.mL-1 for atropine and 31 and 93 µg.mL-1 for scopolamine, allowing a reliable quantitation of the target alkaloids. The solvent system Methanol/acetonitrile was the better choice for extracting tropane alkaloids from different Datura parts. Capsule parts of the plant accumulate the highest amount of scopolamine, while seeds accumulate the higher amount of atropine. Briefly, the order of scopolamine concentrations in Datura metel parts, from Lebanon, was in capsules ˃ seeds ˃ leaves ˃ stems and for atropine, the concentrations were in seeds ˃ capsules ˃ stems ˃ leaves.

Study of the occurrence of toxic alkaloids in forage grass by liquid chromatography tandem mass spectrometry

The toxic alkaloids in forage grass present a serious health hazard to humans and livestock, especially ergot alkaloids (EAs), pyrrolizidine alkaloids (PAs) and tropane alkaloids (TAs). Hence, there is a need for a simultaneous method that allows these dangerous plant toxins to be determined. A simple and effective method was developed to determine fifteen toxic alkaloids (EAs, PAs and TAs) in forage grass using the QuEChERS method and liquid chromatography tandem mass spectrometry (LC-MS/MS). The developed method was validated with average recoveries ranging from 63.10 to 102.10%, and relative standard deviations lower than or equal to 6.39% were obtained. Good linearity over the concentration range of 10-600 µg/kg dry matter (DM) was observed for the target alkaloids. The determination coefficients R2 calculated for each of the matrix calibration curves were greater than 0.99. The limits of detection and quantification were 5 µg/kg DM and 10 µg/kg DM, respectively. The reproducibility of the method was verified in three laboratories: all of the mean recoveries of 15 alkaloids were higher than 60%, and the relative standard deviations in alkaloids between laboratories were all less than 14.24%. The proposed method was applied to analyse 134 forage grass samples from the meadow steppe of Inner Mongolia to monitor toxic alkaloids. A significant difference in the frequency of contamination was found between different herbage species and different regions.

Development of a novel functionality for a highly efficient imidazole-based ionic liquid non-aqueous solvent system for the complete extraction of target alkaloids from Phellodendron amurense Rupr. under ultrasound-assisted conditions

Solvent application in industrial processes is inevitable due to its required role in dissolving solutes, promoting mass and heat transfer, and facilitating separation and purification processes. Notably, woody plants have a high degree of fibrosis and lignification with a mass transfer barrier effect from their multi-scale structure and complex component effects, which makes it difficult for solvents to seep into these plant cells. An ultrasound-assisted complete extraction in ionic liquid non-aqueous solvent system (UACE-ILNAS) method was successfully designed and applied to achieve excellent extraction of five alkaloid components (berberine, palmatine, jatrorrhizine, magnoflorine and phellodendrine) from the bark and leaves of Phellodendron amurense Rupr. From single-factor design and response surface methodology (RSM), the significant factors affecting the average yield of the alkaloids, the ionic liquid concentration, liquid-solid ratio and ultrasonic irradiation temperature, were optimized. Under the optimal conditions, the average yields of the alkaloids from the bark and leaves of P. amurense were 4.22 ± 0.20 and 2.47 ± 0.12 mg/g, respectively, which were highly consistent with the response surface optimization and kinetics analysis results. The non-aqueous aprotic solvent dimethyl sulfoxide (DMSO) was innovatively used as a co-solvent for the ionic liquid [C4mim][OAc]. The DMSO plays a positive role in promoting penetration, helping cell wall dissolve, reducing viscosity, etc. The proposed method overcomes the poor water solubility of isoquinoline alkaloids and the negative effects from the high viscosity of ionic liquids to effectively guarantee the alkaloid quality and yield. In addition, ultrasound plays a reinforcing role in achieving full extraction. Therefore, the developed method shows good application prospects for the separation of low-polarity constituents, especially those present in woody plants.

Aporphine Alkaloids from Triclisia dictyophylla Diels by pH-Zone Refining Countercurrent Chromatography

A new dimeric aporphine alkaloid, biscocsarmine, 2, together with lirioferine, 1, and cocsarmine, 3, were isolated from the ethanol extract of the stems of Triclisia dictyophylla Diels (Menispermaceae) using a preparative pH-zone refining CCC in a single step. The first solvent system family tested for this fractionation was hexane–ethyl acetate–methanol–water (HEMWat) at a series of solvent ratios, and hydrochloric acid and triethylamine at 5 mM as eluter/retainer. None of these HEMWat ratios, however, gave suitable K for the target alkaloids. Ethyl acetate–n-butanol–water (EBuWat) was tested instead and the selected solvent system was composed of ethyl acetate–n-butanol–water 5:5:10 (v/v), where triethylamine (60 mM) was added to the upper organic stationary phase as a retainer and hydrochloric acid (5 mM) to the aqueous mobile phase as an eluter. The chemical structures of the isolated compounds were elucidated based on comprehensive spectroscopic and spectrometric techniques. This is the first report of aporphine alkaloids in this plant species.

A combined pathway for the synthesis of nitidine family alkaloids

Three related alkaloids, oxynitidine, nitidine and 5,6-dihydronitidine, have been afforded by the new synthetic protocols. In this approach, the Ni-catalyzed annulation reaction is indicated as the key step to construct the isoquinolinone core structure. The subsequent transformations lead to the target alkaloids.

Magnoflorine from Coptis chinese has the potential to treat DNCB-induced Atopic dermatits by inhibiting apoptosis of keratinocyte

AimsIn Sheng Nong’s herbal classic in China, Rhizoma coptidisaRC: Rhizoma coptidisa(RC) could be used to treat Atopic dermatitsbAD: Atopic dermatitsb(AD), but its core ingredient(s) and mechanism remains unknown. The present study aimed to find out the ingredients against AD and expound its mechanisms. Materials and methodsSeven alkaloids were isolated from RC to compare the inhibition against HaCaT cells by MTT assays and apoptosis of cells stimulated with TNF-α/IFN-γ by flow cytometry. The effects of target alkaloids against AD were evaluated on DNCBcDNCB: 2,4-dinitrochlorobenzenec (2,4-dinitrochlorobenzene)-induced atopic dermatitis in mice. Key findingsSeven alkaloids were isolated from RC successfully. The results from MTT and flow cytometry indicated that among these alkaloids, only magnoflorine dMAG: magnoflorined(MAG) had no obvious toxicity on cells, but could inhibit the apoptosis of the cells stimulated with TNF-α/IFN-γ. Further animal experiments confirmed that MAG significantly attenuated the AD-like symptom and inhibited the AD-induced increases in IgE/IL-4, as compared with control (P < 0.01). Moreover, MAG reduced the low ΔψmeΔψm: mitochondrial membrane potentiale(mitochondrial membrane potential) in HaCaT cells. The results of western blotting proved that MAG inhibited apoptosis of keratinocytes through decreasing the expressions of CTSBfCTSB: cathepsin Bf (cathepsin B), Cyte CgCyte C: cytochrome Cg (cytochrome C), Bid and caspase-3/7/8/9. SignificanceOverall, MAG inhibited apoptosis by decreasing the expression of apoptotic pathway-related proteins, and laid a foundation for the study of AD mechanisms.

Rapid profiling of alkaloid analogues in Sinomenii Caulis by an integrated characterization strategy and quantitative analysis

Alkaloids, the principal constituents in the caulis of Sinomenium acutum, have gained an increasing interest over the past decades since they are widely employed as a clinical treatment for rheumatoid arthritis. In the present study, an integrated characterization strategy by combining mass defect filtering-based structure classification (MDFSC) and diagnostic fragment-ion-based extension (DFIBE) was firstly proposed for rapid profiling of alkaloids in Sinomenii Caulis (SC) via ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS). The rectangular MDFSC window could more accurately screen the target alkaloids of different types, and the DFIBE could facilitate the acquisition of characteristic fragment ions for structural elucidation of alkaloids. High-performance liquid chromatography (HPLC) fingerprints with principal component analysis (PCA) and hierarchical clustering analysis (HCA) was established for identifying the chemical markers and simultaneous determination of sinomenine, magnoflorine, menisperine, stepharanine and ehydrodiscretine. A total of 91 alkaloids, including 82 targeted ones (26 morphinans, 22 aporphines, 20 protoberberines and 14 benzylisoquinolines) were unambiguously identified or tentatively characterized in SC, and 14 of them were reported for the first time. Sinomenine and magnoflorine could be selected as chemical markers to evaluate the quality of SC from different localities. In conclusion, the proposed method provided a potential approach for chemical profiling and holistic quality control of herbal medicines.

Analysis of acetylcholinesterase inhibitors by extraction in choline saccharinate aqueous biphasic systems

Ionic liquid-based aqueous biphasic systems (IL-ABS) formed by ILs composed of ions of low toxicity, choline ([Chol]+) coupled with saccharinate ([Sac]−) and acesulfamate ([Ace]−), and inorganic salts with distinct water-structuring properties were employed for simultaneous extraction and concentration of acetylcholinesterase (AChE) inhibitors – galantamine (gal), N-desmethyl galantamine (des) and ungiminorine (ung). Comprehensive experiments aimed to assess the influence of salt and IL type and concentration, as well as the pH and temperature on the phase-forming ability and distribution of the target alkaloids between the two phases formed reveled that the IL anion and pH are the most important factors. At the optimal conditions found a quantitative recovery into the IL-rich phase of gal, des and ung was achieved in a single extractive step. These results were further used as a platform for the development of a simple and safer sample pretreatment method for analysis of the three analytes, followed by RP-HPLC/UV detection. The method showed satisfactory analytical performance, the latter allowing quantitative determination of these AChE inhibitors in pharmaceutical dosage form and in human urine.

The New Type of Liquid Chromatography—Colloidal High-Performance Liquid Chromatography (CHPLC): Further Applications

The recent paper by I. Brondz (2018), “One-Step Procedure for Direct Purification of Pediocin-Like Bacteriocins and Cationic Antimicrobial Peptides from Complex Culture Medium on an Analytical, Semipreparative, and Preparative Scale. A New Type of Liquid Chromatography—Colloidal High-Performance Liquid Chromatography (CHPLC)” (International Journal of Analytical Mass Spectrometry and Chromatography, 6, 41-49, https://doi.org/10.4236/ijamsc.2018.63004), described a new type of CHPLC. This technique allows colloidal liquids and suspensions to be chromatographed directly despite the presence in the liquids of material such as bacteria, fungi, and other soft and hard particles. The significance of this development lies in enabling the single-step cleanup and concentration of the target substance from a complex mixture of soluble molecules in the presence of insoluble particles by high performance liquid chromatography (HPLC). The technique also allows the use of viscose liquids (as described in Brondz (2018) that are not suitable for analysis by conventional HPLC. In the previous paper, emphasis was placed on describing the applications of the techniques for the preparation of target substances such as small peptides, bacteriocins, bacitracin, and lysosome. Normally, the industrial preparation of these substances requires multistep procedures, which are time- and labor-consuming, and typically results in significant loss of target material and specific activity. In the present paper, the application of CHPLC for the isolation of alkaloids from crude raw material such as opium cake is demonstrated. In the opium cake, large amounts of hard vegetable particles and even sand corns are present together with the target alkaloids. Despite this, isolation by CHPLC of the desired compound was achieved in a single step by using a water/ethanol-based liquid. Isolation of alkaloids from such raw material normally requires a multistep procedure that includes the preparation of insoluble tartrate or picrate complex and this process includes dissolving the substance in flammable organic liquid. The isolation described here was performed in a single step by using the water/ethanol-based liquid.

Determination of tropane alkaloids by heart cutting reversed phase - Strong cation exchange two dimensional liquid chromatography.

Current Chinese Pharmacopoeia (ChP) standards apply liquid extraction combined with one dimensional liquid chromatography (1DLC) method for determining alkaloids in herbal medicines. The complex pretreatments lead to a low analytical efficiency and possible component loss. In this study, a heart cutting reversed phase - strong cation exchange two dimensional liquid chromatography (RP - SCX 2DLC) approach was optimized for simultaneously quantifying tropane alkaloids (anisodine, scopolamine and hyoscyamine) in herbal medicines and herbal medicine tablets without further treatment of the filtered extract. The chromatographic conditions were systematically optimized in terms of column type, mobile phase composition and flow rate. To improve peak capacity and obtain symmetric peak shape of alkaloids, a polar group embedded C18 column combined with chaotropic salts was used in the first dimension. To remove the disturbance of non-alkaloids, achieve unique selectivity and acquire symmetric peak shape of alkaloids, an SCX column combined with phosphate buffer was used in the second dimension. Method validation was performed in terms of linearity, precision (0.54-0.82%), recovery (94.1-105.2%), limit of detection (LOD) and limit of quantification (LOQ) of the three analytes varied between 0.067-0.115mgL-1 and 0.195-0.268mgL-1, respectively. The method demonstrated superiority over 1DLC method in respect of resolution (less alkaloid co-eluted), sample preparation (no pretreatment procedure) and transfer rate (minimum component loss). The optimized RP - SCX 2DLC approach was subsequently applied to quantify target alkaloids in five herbal medicines and herbal medicine tablets from three different manufactures. The results demonstrated that the developed heart cutting RP - SCX 2DLC approach represented a new, strategically significant methodology for the quality evaluation of tropane alkaloid in related herbal medicines that involve complex chemical matrix.

Mass defect filtering-oriented classification and precursor ions list-triggered high-resolution mass spectrometry analysis for the discovery of indole alkaloids from Uncaria sinensis

Discovery of new natural compounds is becoming increasingly challenging because of the interference from those known and abundant components. The aim of this study is to report a dereplication strategy, by integrating mass defect filtering (MDF)-oriented novelty classification and precursor ions list (PIL)-triggered high-resolution mass spectrometry analysis, and to validate it by discovering new indole alkaloids from the medicinal herb Uncaria sinensis. Rapid chromatographic separation was achieved on a Kinetex® EVO C18 column (<16min). An in-house MDF algorithm, developed based on the informed phytochemistry information and molecular design, could more exactly screen the target alkaloids and divide them into three novelty levels: Known (KN), Unknown-but-Predicted (UP), and Unexpected (UN). A hybrid data acquisition method, namely PIL-triggered collision-induced dissociation-MS2 and high-energy C-trap dissociation-MS3 with dynamic exclusion on a linear ion trap/Orbitrap mass spectrometer, facilitated the acquisition of diverse product ions sufficient for the structural elucidation of both indole alkaloids and the N-oxides. Ultimately, 158 potentially new alkaloids, including 10 UP and 108 UN, were rapidly characterized from the stem, leaf, and flower of U. sinensis. Two new alkaloid compounds thereof were successfully isolated and identified by 1D and 2D NMR analyses. The varied ring E and novel alkaloid-acylquinic acid conjugates were first reported from the whole Uncaria genus. Conclusively, it is a practical chemical dereplication strategy that can enhance the efficiency and has the potential to be a routine approach for the discovery of new natural compounds.

C18-COOH Silica: Preparation, Characterisation and Its Application in Purification of Quaternary Ammonium Alkaloids from Coptis chinensis.

Traditional methods for isolating and purifying quaternary ammonium alkaloids from Coptis chinensis do not discriminate the target alkaloids from co-extractives. Mixed-mode analytical chromatography has the potential to improve the separation of analytes in more complex extracts and, when used in a solid-phase extraction mode, improve the purity of isolated compounds. To examine the high-performance liquid chromatographic separation capabilities of a mixed-mode, silica-based adsorbent and its application to the purification of quaternary ammonium alkaloids from Coptis chinensis based on solid-phase extraction. The C18-COOH silica was prepared via "thiol-ene" click chemistry. Its chromatographic performance was firstly investigated. It was employed as the solid-phase extraction sorbent to purify quaternary ammonium alkaloids. Hydrophobic, attractive/repulsive electrostatic and ion-exchange interactions were demonstrated to be the possible retention mechanisms of a C18-COOH silica stationary phase, which could separate analytes of various properties. In addition, to purify quaternary ammonium alkaloids from Coptis chinensis, the solid-phase extraction approach based on the C18-COOH silica provided a slightly higher purification efficiency (6.7%) than an alkaloid-salt precipitation protocol (5.3%). The method had satisfactory reproducibility, re-using the same solid-phase extraction column three times, with relative standard deviations ranging from 1.99% to 8.02% for the six target alkaloids. A multi-functionalised silica was synthesised via "click chemistry". As the high-performance liquid chromatographic stationary phase, the C18-COOH silica could be operated in trimodal reversed-phase/weak cation exchange/hydrophilic interaction mode. The C18-COOH silica also exhibited potential as solid-phase extraction sorbent in the purification of quaternary ammonium alkaloids from complex matrices. Copyright © 2017 John Wiley & Sons, Ltd.

Separation of matrine and oxymatrine from Sophora flavescens extract through cation exchange resin coupled with macroporous absorption resin

Abstract A simple method for separation of matrine and oxymatrine from Sophora flavescens was developed with cation exchange resin coupled with macroporous resin. Based on the adsorption characteristics of matrine and oxymatrine, 001×732 cation exchange resin was used to absorb target alkaloids for removing most of the foreign matter, while BS-65 macroporous resin was chosen to purify these alkaloids. The result showed that the equilibrium adsorption data of matrine and oxymatrine on 001×732 resin and BS-65 resin at 30°C was fitted to Langmuir isotherm and Freundlich isotherm, respectively. The contents of matrine and oxymatrine were increased from 0.73% and 2.2% in the crude extract of the root of Sophora flavescens to 67.2% and 66.8% in the final eluent products with the recoveries of 90.3% and 86.9%, respectively.