Discovery of natural AMPK activator from the fruits of Xanthium sibiricum Patr.: Xanthiumine A, protoberberine alkaloid with unique C28 skeleton.

Two protoberberine alkaloids with a unique C28 skeleton, named xanthiumines A (1) and B (2), respectively, were isolated from the fruits of Xanthium sibiricum Patr. Their structures including absolute configurations were unequivocally established by the comprehensive NMR and MS spectroscopic data analysis together with gauge-independent atomic orbital (GIAO) NMR calculations, and electronic circular dichroism (ECD) calculations. Compounds 1 and 2 are the first examples of natural protoberberine alkaloid with a phenolic acid group at C-13a. Their plausible biosynthetic pathway was proposed on the basis of the coexisting alkaloid monomer as the precursor. Furthermore, the effects and related molecular mechanism of compound 1 on hepatic lipid accumulation were also investigated in oleic acid (OA)-treated HepG2 cells.

Synergistic Dose Permutation of Isolated Alkaloid and Sterol for Anticancer Effect on Young Swiss Albino Mice.

INTRODUCTION: Synergy is defined as an interaction of some substances that cooperate to give rise to the combined effect greater than the sum of their individual effects. It is a natural strategy that has evolved by nature to more efficacy with low cost. METHODS: This study is designed to evaluate the chemopreventive effect of a combined drug sample which is prepared by mixing an equal portion of stigmasterol and palmatine isolated from Azadirachta indica and Tinospora cordifolia respectively at a concentration of 100 mg/kg and 200 mg/kg body weight during the whole concentration. RESULTS: At the end of the study, it was found that this combined drug sample decreased the number of tumors and their size. This drug significantly reduced the serum level of glutamate pyruvate transaminase, alkaline phosphatase, glutamate oxalate transaminase, and bilirubin and enhanced the level of oxidative enzyme level of glutathione, superoxide dismutase, and catalase, and inhibit the level of lipid peroxides. DISCUSSION: The result suggests that combined drug samples exhibit a chemopreventive effect which is better than the effect of individual drugs (stigmasterol and palmatine).

The Phytochemical Scoulerine Inhibits Aurora Kinase Activity to Induce Mitotic and Cytokinetic Defects.

To identify novel bioactive compounds, an image-based, cell culture screening of natural product extracts was conducted. Specifically, our screen was designed to identify phytochemicals that might phenocopy inhibition of the chromosomal passenger protein complex in eliciting mitotic and cytokinetic defects. A known alkaloid, scoulerine, was identified from the rhizomes of the plant Corydalis decumbens as being able to elicit a transient mitotic arrest followed by either apoptosis induction or polyploidy. In examining the mitotic abnormality further, we observed that scoulerine could elicit supernumerary centrosomes during mitosis, but not earlier in the cell cycle. The localization of NUMA1 at spindle poles was also inhibited, suggesting diminished potential for microtubule recruitment and spindle-pole focusing. Polyploid cells emerged subsequent to cytokinetic failure. The concentration required for scoulerine to elicit all its cell division phenotypes was similar, and an examination of related compounds highlighted the requirement for proper positioning of a hydroxyl and a methoxy group about an aromatic ring for activity. Mechanistically, scoulerine inhibited AURKB activity at concentrations that elicited supernumerary centrosomes and polyploidy. AURKA was only inhibited at higher concentrations, so AURKB inhibition is the likely mechanism by which scoulerine elicited division defects. AURKB inhibition was never complete, so scoulerine may be a suboptimal AURK inhibitor or work upstream of the chromosomal passenger protein complex to reduce AURKB activity. Scoulerine inhibited the viability of a variety of human cancer cell lines. Collectively, these findings uncover a previously unknown activity of scoulerine that could facilitate targeting human cancers. Scoulerine, or a next-generation analogue, may be useful as a nontoxic component of combination therapies where inhibiting the chromosomal passenger protein complex is desired.

Chemoenzymatic Cascades toward Methylated Tetrahydroprotoberberine and Protoberberine Alkaloids.

Tetrahydroprotoberberine and protoberberine alkaloids are a group of biologically active natural products with complex molecular scaffolds. Isolation from plants is challenging and stereoselective synthetic routes, particularly of methylated compounds are limited, reducing the potential use of these compounds. In this work, we describe chemoenzymatic cascades toward various 13-methyl-tetrahydroprotoberberbine scaffolds using a stereoselective Pictet-Spenglerase, regioselective catechol O-methyltransferases and selective chemical Pictet-Spengler reactions. All reactions could be performed sequentially, without the workup or purification of any synthetic intermediates. Moreover, the naturally occurring alkaloids have the (+)-configuration and importantly here, a strategy to the (-)-isomers was developed. A methyl group at C-8 was also introduced with some stereocontrol, influenced by the stereochemistry at C-13. Furthermore, a single step reaction was found to convert tetrahydroprotoberberine alkaloids into the analogous protoberberine scaffold, avoiding the use of harsh oxidizing conditions or a selective oxidase. This work provides facile, selective routes toward novel analogues of bioactive alkaloids.

Analgesic effect of the main components of Corydalis yanhusuo (yanhusuo in Chinese) is caused by inhibition of voltage gated sodium channels.

ETHNOPHARMACOLOGY RELEVANCE: Pain often causes a series of abnormal changes in physiology and psychology, which can lead to disease and even death. Drug therapy is the most basic and commonly used method for pain relief and management. Interestingly, at present, hundreds of traditional Chinese medicines have been reported to be used for pain relief, most of which are monomer preparations, which have been developed into new painkillers. Corydalis yanhusuo is a representative of one of these medicines and is available for pain relief. AIM OF THE STUDY: This study aims to determine the analgesic effect and the potential targets of the monomers derived from Corydalis yanhusuo, and to explore any possible associated cardiac risk factors. MATERIALS AND METHODS: In this study, four monomers derived from Corydalis yanhusuo (tetrahydropalmatine, corydaline, protopine, dehydrocorydaline) were tested in vivo, using the formalin-induced pain model to determine their analgesic properties. Their potential targets were also determined using whole cell patch clamp recordings and myocardial enzyme assays. RESULTS: The results showed that all monomers showed analgesic activity and inhibited the peak currents, promoted the activation and inactivation phases of Nav1.7, which indicating that Nav1.7 might be involved in the analgesic mechanism of Corydalis yanhusuo. Protopine increased the level of creatine kinase-MB (CK-MB) and inhibited the peak currents, promoted the activation and inactivation phases of Nav1.5, indicating that Nav1.5 might be involved in the cardiac risk associated with protopine treatment. CONCLUSION: These data showed that tetrahydropalmatine produced the best analgesic effect and the lowest cardiac risk. Thus, voltage gated sodium channels (VGSCs) might be the main targets associated with Corydalis yanhusuo. This study, therefore, provides valuable information for future studies and use of traditional Chines medicines for the alleviation of pain.

Identification and Quantification, Metabolism and Pharmacokinetics, Pharmacological Activities, and Botanical Preparations of Protopine: A Review.

Through pharmacological activity research, an increasing number of natural products and their derivatives are being recognized for their therapeutic value. In recent years, studies have been conducted on Corydalis yanhusuo W.T. Wang, a valuable medicinal herb listed in the Chinese Pharmacopoeia. Protopine, one of its components, has also become a research hotspot. To illustrate the identification, metabolism, and broad pharmacological activity of protopine and the botanical preparations containing it for further scientific studies and clinical applications, an in-depth and detailed review of protopine is required. We collected data on the identification and quantification, metabolism and pharmacokinetics, pharmacological activities, and botanical preparations of protopine from 1986 to 2021 from the PubMed database using "protopine" as a keyword. It has been shown that protopine as an active ingredient of many botanical preparations can be rapidly screened and quantified by a large number of methods (such as the LC-ESI-MS/MS and the TLC/GC-MS), and the possible metabolic pathways of protopine in vivo have been proposed. In addition, protopine possesses a wide range of pharmacological activities such as anti-inflammatory, anti-platelet aggregation, anti-cancer, analgesic, vasodilatory, anticholinesterase, anti-addictive, anticonvulsant, antipathogenic, antioxidant, hepatoprotective, neuroprotective, and cytotoxic and anti-proliferative activities. In this paper, the identification and quantification, metabolism and pharmacokinetics, pharmacological activities, and botanical preparations of protopine are reviewed in detail to lay a foundation for further scientific research and clinical applications of protopine.

Synthesis and characterization of core-shell magnetic molecularly imprinted polymers for selective extraction of allocryptopine from the wastewater of Macleaya cordata (Willd) R. Br.

A novel type of magnetic molecularly imprinted polymers (MMIP) as the solid-phase extraction sorbent was prepared, which can extract effectively the allocryptopine from the waster of Macleaya cordata (Willd) R. Br. In this study, MMIP was synthesized by using Fe3 O4 @SiO2 , 4-vinyl-pyridine, ethylene glycol dimethacrylate, and allocryptopine, and these ingredients worked as magnetic core, functional monomer, cross-linker, and template, respectively. Concluded by the calculation of Gaussian 09 software, different ratio models of 4-vinyl-pyridine and allocryptopine were simulated, and the optimal ratio was 1:5 and the energy was -2205.34 kJ/mol. Transmission electron microscopy, vibration sample magnetometry, X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis were used to determine the morphology and structure of MMIP. Furthermore, the results of adsorption experiments indicated that MMIP had high selectivity, excellent recyclability, and good adsorption performance (9.86 mg/g, 298 K). The adsorption process was consistent with the Langmuir adsorption isotherm (R2 > 0.98, 298 K) and pseudo-second-order kinetics model (R2 > 0.99, 298 K). After six times adsorption-desorption experiments, the adsorption amount of MMIP only reduced to 8.5%. In the experiments of selective adsorption, MMIP has better adsorption properties for allocryptopine (ALL, C21 H23 NO5 ) than those having the same functional group. The limit of detection (LOD) was 0.4 µg/mL. The relative standard deviation ranged from 0.09% to 0.72%. The recovery of allocryptopine in samples ranged from 93.60% to 106.19%. In addition, the synthesized complex had a certain adsorption effect on allocryptopine separating from the wastewater of Macleaya cordata (Willd) R. Br.

[Simultaneous Quantitative Analysis of Berberine and Other Alkaloids in Powdered Phellodendron Bark].

Phellodendron bark ("Obaku") is an important crude drug used in Kampo-medicine. Recently, powder formulation of phellodendron bark was approved as an "efficacious treatment for bruise, sprain, and periodontal diseases", and it has been marketed as an OTC agent. To obtain this approval, the examination of quality control-related characteristics is necessary. Therefore, we established a quantitative method for jatrorrhizine, palmatine, and berberine determination. In this study, we compared the contents of the three constituents obtained from the extracts of Japanese and Chinese phellodendron bark and found remarkable difference.

Octahydro-Protoberberine and Protoemetine-Type Alkaloids from the Stems of Alangium salviifolium and Their Cytotoxicity.

Two octahydro-protoberberine alkaloids, alangiifoliumines A (1) and B (2), and two new protoemetine derivatives, alangiifoliumines C (3) and D (4), together with 11 known compounds, have been isolated from the stems of Alangium salviifolium. While the structures of these compounds were elucidated by spectroscopic methods, the absolute configurations of the new alkaloids were determined by conformational analysis and time-dependent density functional theory-electronic circular dichroism spectra calculations on selected stereoisomers. Compounds 1 and 2 represent the first 5,8,8a,9,12,12a,13,13a-octahydro-protoberberine derivatives, in which the aromatic ring D was reduced to cyclohexene. All the compounds isolated were evaluated for their cytotoxic activity against three human cancer cell lines: A-549, HeLa, and SKOV-3. Alkaloids 1, 3, and 6-14 exhibited inhibitory effects against all three human cancer cell lines, with half-maximal inhibitory concentration (IC50) values in the range of 3 nM to 9.4 µM.

Protoberberine compounds extracted from Chelidonium majus L. as novel natural photosensitizers for cancer therapy.

BACKGROUND: It has been shown that secondary metabolites occur in Chelidonium majus L. (C. majus) crude extract and milky sap (alkaloids such as berberine, coptisine, chelidonine, chelerythrine, sanguinarine, and protopine) are biologically active compounds with a wide spectrum of pharmacological functions. Berberine, an isoquinoline alkaloid extracted from plants, possesses a wide range of biological activities, including inhibition of growth of a variety of cancer cell lines. PURPOSE AND STUDY DESIGN: In the present study, we investigated the potential anticancer effect of a protoberberine alkaloidal fraction (BBR-F) isolated from the medicinal plant C. majus on HeLa and C33A cervical cancer cells after light irradiation (PDT treatment). METHODS: BBR-F was prepared from an ethanolic extract of stems of C. majus. Identification of alkaloidal compounds was performed using high-performance liquid chromatography - mass spectrometry (HPLC/ESI-MS) and nuclear magnetic resonance (NMR) spectroscopy. BBR-F was then biologically evaluated for its anticancer properties. Cytotoxic activity after PDT treatment and without light irradiation (dark cytotoxicity) was determined by colorimetric WST-1 assay. The impact of the protoberberine alkaloidal fraction on the morphology and function of the cells was assessed by fluorescence and confocal microscopy as well as by flow cytometric analysis. To investigate the proinflammatory effect of the extracted natural BBR-F, nitric oxide concentration was determined using the Griess method. RESULTS: An effective reduction in HeLa and C33A cell viability was observed after PDT treatment of BBR-F treated cells. Furthermore, microscopic analysis identified various morphological changes in the studied cells that occurred during apoptosis. Apoptosis of HeLa and C33A cells was also characterized by biochemical changes in cell membrane composition, activation of intracellular caspases, disruption of the mitochondrial membrane potential (Δψm) and reactive oxygen species (ROS) generation. CONCLUSION: Our results strongly suggest that the components of the natural plant protoberberine fraction (BBR-F) extracted from C. majus may represent promising novel photosensitive agents and can be applied in cancer photodynamic therapy as natural photosensitizers.

Detection of coralyne and heparin by polymerase extension reaction using SYBR Green I.

Polydeoxyadenosine (poly (dA)) has been extensively applied for detecting many drug molecules. Herein, we developed a sensitive method for detecting coralyne and heparin using a modified DNA probe with poly (dA) at one end. In the absence of coralyne, the DNA probe was digested by the Exonuclease I (Exo I), and therefore the SYBR Green I (SG I) emitted an extremely low fluorescent signal. While coralyne specifically binding to poly (dA) with strong propensity could remarkably restrain the disintegration of the DNA probe, through which as a template the second strand of DNA sequence was formed with the introduction of DNA polymerase. Therefore, the fluorescent signal of SG I was intensified to quantify coralyne. Based on this method, heparin can be determined due to its strong affinity towards coralyne. This method showed a linear range from 2 to 500 nM for coralyne with a low detection limit of 0.98 nM, and the linear range of heparin was from 1 to 100 nM when 1.25 nm was the detection limit. The proposed method was also implemented successfully in biological samples and showed a potential application for screening potential therapeutic molecules.

Epinephrine-modified methacrylate monolithic column with fumed silica nanoparticle for pressurized capillary electrochromatography.

Via the ring-opening reaction of epoxy groups with epinephrine, a novel epinephrine functionalized polymethacrylate monolith with fumed silica nanoparticles has been fabricated for pressurized capillary electrochromatography. The preparation of epinephrine-modified monoliths has been optimized. In addition, morphology, electroosmotic flow, separation mechanism and column performance have been studied. The internal structure of the monolithic stationary phase was more uniform and the column efficiency increased after the incorporation of nanoparticles. With this column, satisfactory separation capability of aromatic compounds and alkaloids has been achieved and the column efficiency for naphthalene reached 138 696 plates/m. As for the real sample, 3 alkaloids were separated in Huanglian Shangqing capsules, a Chinese traditional medicine.

Protopine isolated from Nandina domestica induces apoptosis and autophagy in colon cancer cells by stabilizing p53.

The tumor suppressor p53 plays essential roles in cellular protection mechanisms against a variety of stress stimuli and its activation induces apoptosis or autophagy in certain cancer cells. Here, we identified protopine, an isoquinoline alkaloid isolated from Nandina domestica, as an activator of the p53 pathway from cell-based natural compound screening based on p53-responsive transcription. Protopine increased the p53-mediated transcriptional activity and promoted p53 phosphorylation at the Ser15 residue, resulting in stabilization of p53 protein. Moreover, protopine up-regulated the expression of p21WAF1/CIP1 and BAX, downstream genes of p53, and inhibited the proliferation of HCT116 colon cancer cells. Apoptosis was elicited by protopine as indicated by caspase-3/7 activation, poly ADP ribose polymerase cleavage, and increased population of Annexin V-FITC-positive cells. Furthermore, protopine induced the formation of microtubule-associated protein 1 light chain 3 (LC3) puncta and LC3-II turnover, typical biochemical markers of autophagy, in HCT116 cells. Our findings suggest that protopine exerts its antiproliferative activity by stimulating the p53 pathway and may have potential as a chemopreventive agent for human colon cancer.

Application of UPLC-MS/MS to simultaneously detect four bioactive compounds in the tumour-shrinking decoction (FM1523) for uterine fibroids treatment.

INTRODUCTION: The Chinese medicine formulation, tumour-shrinking decoction (TSD, FM1523), which consists of 15 natural medicines, is used for uterine fibroids (UFs) therapy and possesses excellent clinical therapeutic effect. OBJECTIVE: To develop a sensitive and validated analytical method for the simultaneous quantification of four crucial bioactive compounds including isorhamnetin-3-O-neohesperidoside, curcumin, peimine and tetrahydropalmatine in the principal formulation of this decoction. METHODS: An ultra-performance liquid chromatography coupled tandem mass spectrometry (UPLC-MS/MS) with an electrospray ionisation (ESI) source in multiple reaction monitoring (MRM) mode was conducted to investigate these bioactive compounds in the TSD. The chromatographic separation was performed on a C18 column when the flow rate was adjusted at 0.2 mL/min with gradient elution of acetonitrile-water with 0.1% formic acid. Accelerated solvent extraction (ASE) method with higher extraction efficiency was employed for TSD sample pre-treatment. RESULTS: The linearity, limit of detection (LOD) and limit of quantification (LOQ) were determined for this analytical method. The mean recoveries of the compounds were determined between 100.23% and 104.02% with satisfactory relative standard deviation (RSD) in the ranges of 2.65% to 3.81%. The precision was evaluated by intra-day and inter-day tests, which revealed RSD within the ranges of 1.21% to 2.14% and 1.24% to 2.32%, respectively. CONCLUSION: The bioactive compounds of TSD samples were successfully quantified via UPLC-MS/MS with MRM mode. This study could help to evaluate the pharmacokinetic study of TSD during clinical applications and present a facile strategy for quantifying bioactive compounds in traditional Chinese Medicine decoction.

Large-scale separation of acetylcholinesterase inhibitors from Zanthoxylum nitidum by pH-zone-refining counter-current chromatography target-guided by ultrafiltration high-performance liquid chromatography with ultraviolet and mass spectrometry screening.

A new strategy by converging ultrafiltration high-performance liquid chromatography with ultraviolet and mass spectrometry and pH-zone-refining counter-current chromatography was developed for the rapid screening and separation of potential acetylcholinesterase inhibitors from the crude alkaloidals extract of Zanthoxylum nitidum. An optimized two-phase solvent system composed of chloroform/methanol/water (4:3:3, v/v) was used in this study. And, in the optimal solvent system, 45 mM hydrochloric acid was added to the aqueous stationary phase as the retainer, while 5 mM triethylamine was added to the organic mobile phase as the eluter. As a result, with the purity of over 95%, five alkaloids including jatrorrhizine (1, 340 mg), columbamine (2, 112 mg), skimmianine (3, 154 mg), palmatine (4, 226 mg), and epiberberine (5, 132 mg) were successfully purified in one step from 3.0 g crude alkaloidals extract. And their structures were identified by ultraviolet, mass spectrometry, 1 H and 13 C NMR spectroscopy. Notably, compounds 2, 4 and 5 were firstly reported in Z. nitidum. In addition, acetylcholinesterase inhibitory activities of compounds 1-5 were evaluated, and compounds 3, 4 and 5 exhibited stronger acetylcholinesterase inhibitory activity (IC50 values at 8.52 ± 0.64, 14.82 ± 1.21 and 3.12 ± 0.32 µg/mL, respectively) than berberine (IC50 value at 32.86 ± 2.14 µg/mL, positive control). The results indicated that the proposed method is an efficient technique to rapidly screen acetylcholinesterase inhibitors from complex samples, and could be served as a large-scale preparative technique for separating ionizable active compounds.

Sodium dodecyl sulfate sensitized switchable solvent liquid-phase microextraction for the preconcentration of protoberberine alkaloids in Rhizoma coptidis.

A sodium dodecyl sulfate sensitized switchable solvent liquid-phase microextraction method was developed and applied to the preconcentration of active alkaloids in Rhizoma coptidis followed by high performance liquid chromatography determination. Before extraction, nonionic triethylamine was converted to its cationic form in the presence of carbon dioxide. Then, the ionic solvent carrying target analytes was once more reverted to its nonionic form by adding sodium hydroxide, as well as phase separation and analytes enrichment were realized simultaneously. Several parameters affecting the approach, such as concentration of sodium dodecyl sulfate, extraction solvent volume, sodium hydroxide concentration, sample phase pH, injection solvent type, and extraction time, were investigated and optimized. The possible microextraction mechanism of double micelle supramolecular inclusion was explored. Under the optimum conditions, the enrichment factors of four protoberberine alkaloids were from 101.8 to 152.0. The linear ranges (with r2  ≥ 0.990) were 0.032-4.23, 0.031-4.33, 0.0026-10.04, and 0.0013-4.13 µg/mL for epiberberine, coptisine, palmatine, and berberine, respectively. The detection limits were in the range of 0.16-0.32 ng/mL. Satisfactory accuracies (recoveries 98.8-104.6%) and precisions (RSDs 1.9-10.9%) were also obtained. The results showed that the approach is rapid, effective, eco-friendly, and easy-to-handle for the enrichment and detection of active alkaloids in Rhizoma coptidis.

Modification and Characterization of Fe3O4 Nanoparticles for Use in Adsorption of Alkaloids.

Magnetite (Fe3O4) is a ferromagnetic iron oxide of both Fe(II) and Fe(III), prepared by FeCl2 and FeCl3. XRD was used for the confirmation of Fe3O4. Via the modification of Tetraethyl orthosilicate (TEOS), (3-Aminopropyl)trimethoxysilane (APTMS), and Alginate (AA), Fe3O4@SiO2, Fe3O4@SiO2-NH2, and Fe3O4@SiO2-NH2-AA nanoparticles could be obtained, and IR and SEM were used for the characterizations. Alkaloid adsorption experiments exhibited that, as for Palmatine and Berberine, the most adsorption could be obtained at pH 8 when the adsorption time was 6 min. The adsorption percentage of Palmatine was 22.2%, and the adsorption percentage of Berberine was 23.6% at pH 8. Considering the effect of adsorption time on liquid phase system, the adsorption conditions of 8 min has been chosen when pH 7 was used. The adsorption percentage of Palmatine was 8.67%, and the adsorption percentage of Berberine was 7.25%. Considering the above conditions, pH 8 and the adsorption time of 8min could be chosen for further uses.

Cholinesterase inhibitory alkaloids from the rhizomes of Coptis chinensis.

Coptis chinensis has been used as a medicinal herb in traditional oriental medicine. In this study, chemical investigation of a water extract of C. chinensis identified two new quaternary protoberberines (1, 2), a new tricyclic amide (3), together with five known compounds. Their chemical structures were elucidated by analysis with 1D and 2D NMR and high-resolution mass spectroscopy, as well as by comparison with those reported in the literature. Compounds 4, 5, and 7 showed potent inhibition against acetylcholinesterase (AChE) with IC50 values of 1.1, 5.6, and 12.9 µM, respectively. Compounds 2 and 4 showed inhibition of butyrylcholinesterase (BChE) with IC50 values of 11.5 and 27.8 µM, respectively. The kinetic activities were investigated to find out the type of enzyme inhibition involved. The types of AChE inhibition shown by compounds 5 and 7 were noncompetitive; BChE inhibition by compound 2 was also noncompetitive.

In Vivo Disease Control Efficacy of Isoquinoline Alkaloids Isolated from Corydalis ternata against Wheat Leaf Rust and Pepper Anthracnose.

Phytochemicals have been considered as alternatives for synthetic fungicides because of their biodegradability and low toxicity. In this study, we found that the methanolic extract of Corydalis ternata suppressed the development of plant diseases caused by Puccinia triticina and Colletotrichum coccodes. As the antifungal substance, three isoquinoline alkaloids (dehydrocorydaline, stylopine, and corydaline) were isolated from C. ternata. These active compounds also exhibited in vivo antifungal activity against P. triticina and C. coccodes. Taken together, our results suggest that C. ternata and its active compounds can be used to control plant diseases.

High-throughput screening of triplex DNA binders from complicated samples by 96-well pate format in conjunction with peak area-fading UHPLC-Orbitrap MS.

Conventional strategies for the screening of DNA triplex binders cannot be used for complicated samples, such as ligand libraries created by combinatorial chemistry or from natural product extracts. In the current study, an ultra-high-performance liquid chromatography coupled with an Orbitrap mass spectrometry (UHPLC-Orbitrap-MS)-based approach, which we call peak area-fading (PAF) UHPLC-Orbitrap-MS and was designed for just such a purpose, is reported. The triplex DNA modified 96-well plate and the single stranded oligonucleotide modified 96-well plate (as control) were incubated with ligand libraries, and the unbound ligands were directly determined via UHPLC-ESI-MS. The binders were detected through the decrease (fading) in the peak areas compared to those of the control group. Several factors, such as incubation time, incubation temperature, and buffer, which might affect the binding affinity and reproducibility, were optimized. The potential of the approach was examined using the extracts of Rhizoma Coptidis and Phellodendron chinense Schneid cortexe. The triplex DNA-binding capabilities of the five components (epiberberine, coptisine, jatrorrhizine, berberrubine, and columbamine) were found for the first time, indicating their efficiency for the analysis of complicated samples. In contrast to our previous study, which suffered from a serious drawback of poor reproducibility, this method is more robust and more suitable for high-throughput measurements, opening a new experimental strategy in assessing large libraries of potential drug candidates that work by forming a drug/DNA complex.