Determination of scutellarin in Erigeron breviscapus extract by liquid chromatography-tandem mass spectrometry

Current advances on the therapeutic potential of scutellarin: an updated review

Scutellarin is widely distributed in Scutellaria baicalensis, family Labiatae, and Calendula officinalis, family Asteraceae, and belongs to flavonoids. Scutellarin has a wide range of pharmacological activities, it is widely used in the treatment of cerebral infarction, angina pectoris, cerebral thrombosis, coronary heart disease, and other diseases. It is a natural product with great research and development prospects. In recent years, with in-depth research, researchers have found that wild scutellarin also has good therapeutic effects in anti-tumor, anti-inflammatory, anti-oxidation, anti-virus, treatment of metabolic diseases, and protection of kidney. The cancer treatment involves glioma, breast cancer, lung cancer, renal cancer, colon cancer, and so on. In this paper, the sources, pharmacological effects, in vivo and in vitro models of scutellarin were summarized in recent years, and the current research status and future direction of scutellarin were analyzed.

Dengzhan Shengmai capsules and their active component scutellarin prevent cognitive decline in APP/PS1 mice by accelerating Aβ aggregation and reducing oligomers formation

There is currently no effective treatment to prevent the progress of Alzheimer's disease (AD). The traditional Chinese herbs Dengzhan Shengmai (DZSM) capsules and their active component scutellarin possess multiple effects and are clinically used for the treatment of cerebrovascular diseases. Scutellarin has been reported to affect Aβ aggregation. However, the effects of DZSM capsules on AD remain unknown. Through in vivo experiments, our study proved that the alleviating effects of DZSM capsules on cognitive deficits of AD mice were due to the role of scutellarin, which up-regulated low toxic amyloid plaques and down-regulated highly toxic soluble Aβ42 and Aβ40 levels in cortex. In vitro, we confirmed scutellarin's role in accelerating transforming Aβ42 monomers into high-molecular-mass aggregates by biochemical assays, which supported the results observed in drug-treated APP/PS1 mice. In detail, the 1:10 ratio of scutellarin/Aβ42 mixtures promoted production of large β-sheet-rich fibrils whereas the 1:1 ratio promoted production of protofibrils. In addition, the binding between scutellarin and Aβ monomers was quantified by microscale thermophoresis test and the apparent dissociation constant (Kd) was 1284.4 ± 238.8 μM. What's more, binding regions between scutellarin and Aβ fibrils were predicted by computational docking models and scutellarin might bind parallel to the long axis of Aβ42 fibrils targeting hydrophobic grooves at residues 35-36 or 39. In conclusion, DZSM capsules protected against cognitive defects of AD through scutellarin-mediated acceleration of Aβ aggregation into fibrils or protofibrils and reduction of soluble Aβ oligomers, thus suggesting potential clinical applications of DZSM capsules and scutellarin in the treatment of AD.

Identification of trans-2-cis-8-Matricaria-ester from the Essential Oil of Erigeron multiradiatus and Evaluation of Its Antileishmanial Potential by in Vitro and in Silico Approaches

The essential oil (EO) composition of the aerial parts of Erigeron multiradiatus (Lindl.ex DC.) Benth growing wild in the central Himalayan region of Uttarakhand, India, was analyzed by capillary gas chromatography with a flame ionization detector and gas chromatography-mass spectrometry. A sum of 12 constituents was identified, representing 97.81% of the oil composition. The oil was composed mainly of oxygenated monoterpenes (88.95%), sesquiterpene hydrocarbons (5.61%), oxygenated sesquiterpenes (3.05%), and monoterpene hydrocarbons (0.20%). Major constituents identified were trans-2-cis-8-matricaria-ester (77.79%), cis-lachnophyllum ester (11.04%), zingiberene (4.43%), and spathulenol (1.59%). Further, the leishmanicidal effect of EO and the purified compound trans-2-cis-8-matricaria-ester has been investigated against Leishmania donovani promastigotes and intracellular amastigotes. EO and trans-2-cis-8-matricaria-ester were safer for the hamster peritoneal macrophage and lethal to promastigotes and intracellular amastigotes at different concentrations. Further, using an in silico approach, these four compounds were tested against 10 major proteins of L. donovani associated with its virulence. Out of them, only trans-2-cis-8-matricaria-ester was found to be effective against the four target proteins, namely, l-asparaginase-1-like protein, metacaspase 2, metacaspase 1, and DNA topoisomerase II of L. donovani. The results indicate that EO contains trans-2-cis-8-matricaria-ester as a major component and showed antileishmanial activity which may facilitate discovery of new lead molecules for developing herbal medicines against visceral leishmaniasis.

Systematic investigation of the Erigeron breviscapus mechanism for treating cerebrovascular disease

ETHNOPHARMACOLOGICAL RELEVANCE

Cerebrovascular diseases (CBVDs), characterized by striking morbidity and mortality, have become the most common life-threatening diseases. The existing drugs of CBVDs target one or a few of pathogenic factors, the efficacy of which is limited because of the complexity of CBVDs. Traditional Chinese medicine (TCM), featured by multi-component and multi-target endows the great effectiveness in CBVDs treatment. For instance, Erigeron breviscapus (vant.) Hand. Mazz. （Erigeron breviscapus) has been used to treat CBVDs for a long time and the efficacy has been verified through years' of practice. Nevertheless, the mechanisms of Erigeron breviscapus for treating CBVDs are still unclear.

THE AIM OF THE STUDY

Systematically decipher the mechanisms of Erigeron breviscapus for treating CBVDs.

MATERIALS AND METHODS

The systems pharmacology approach is utilized by integrating ADME pharmacokinetic screening, target fishing, protein-protein interaction (PPI), network analysis and in vitro experiments verification.

RESULTS

First, 14 potentially active molecules were screened out through in silico ADME pharmacokinetic evaluation, most of which have been reported with excellent biological activities. Then 169 targets of active molecules were read out using our in-house softwares, systems drug targeting (sysDT) and Weighted Ensemble Similarity(WES). We found that the targets of the active compounds were significantly enriched to the CBVDs therapeutic targets by analyzing their biological processes and protein-protein interactions (PPIs). A multi-layer network analysis including compound-target network, target-pathway network and "CBVDs pathway" indicated that the Erigeron breviscapus exerts a protective effect on CBVDs via regulating multiple pathways and hitting on multiple targets. Meanwhile in vitro experiments confirmed that the stigmasterol, scutellarein, and daucosterol from Erigeron breviscapus increased the MEK and PLCγ proteins levels, and decreased the expression of Bax, PI3K, and eNOS, which led to the cell survival, proliferation and contraction.

CONCLUSION

The approach used in this work offers a new exemplification for systematically understanding the mechanisms of herbal medicines, which will give an impulse to the CBVDs drug development.

Scutellarin Mitigates Aβ-Induced Neurotoxicity and Improves Behavior Impairments in AD Mice

Alzheimer’s disease (AD) is pathologically characterized by excessive accumulation of amyloid-beta (Aβ) within extracellular spaces of the brain. Aggregation of Aβ has been shown to trigger oxidative stress, inflammation, and neurotoxicity resulting in cognitive dysfunction. In this study, we use models of cerebral Aβ amyloidosis to investigate anti-amyloidogenic effects of scutellarin in vitro and in vivo. Our results show that scutellarin, through binding to Aβ42, efficiently inhibits oligomerization as well as fibril formation and reduces Aβ oligomer-induced neuronal toxicity in cell line SH-SY5Y. After nine months of treatment in APP/PS1 double-transgenic mice, scutellarin significantly improves behavior, reduces soluble and insoluble Aβ levels in the brain and plasma, decreases Aβ plaque associated gliosis and levels of proinflammatory cytokines TNF-α and IL-6, attenuates neuroinflammation, displays anti-amyloidogenic effects, and highlights the beneficial effects of intervention on development or progression of AD-like neuropathology.

Pharmacological Effects of Scutellarin, An Active Component of Genus Scutellaria and Erigeron: A Systematic Review

Flavonoid compound scutellarin (Scu) is quite frequently met in the plant kingdom, particularly in the genus Scutellaria (Lamiaceae) and Erigeron (Asteraceae). The extract of the herb of Erigeron breviscapus, containing this component in high amount, has been used for many years in traditional Chinese medicine. In recent years, studies have made great progress on the usefulness of Scu for treating various diseases by testing its mechanism of action. They support the traditional use of Scu rich plant in heart and cerebral ischemia. Scu can potentially be applied in Alzheimer's disease, Helicobacter pylori infection, vascular complications of diabetes and as an inhibitor of certain carcinomas. Various methods were designed to improve its isolation from plant material, solubility, absorption and bioavailability. On the basis of recent studies, it is suggested that Scu could be a promising candidate for new natural drug and deserves particular attention in further research and development.

Determination of scutellarin in breviscapine preparations using quantitative proton nuclear magnetic resonance spectroscopy

The objective of the present study was to develop the selection criteria of proton signals for the determination of scutellarin using quantitative nuclear magnetic resonance (qNMR), which is the main bioactive compound in breviscapine preparations for the treatment of cerebrovascular disease. The methyl singlet signal of 3-(trimethylsilyl)propionic-2,2,3,3-d₄ acid sodium salt was selected as the internal standard for quantification. The molar concentration of scutellarin was determined by employing different proton signals. To obtain optimum proton signals for the quantification, different combinations of proton signals were investigated according to two selection criteria: the recovery rate of qNMR method and quantitative results compared with those obtained with ultra-performance liquid chromatography. As a result, the chemical shift of H-2′ and H-6′ at δ 7.88 was demonstrated as the most suitable signal with excellent linearity range, precision, and recovery for determining scutellarin in breviscapine preparations from different manufacturers, batch numbers, and dosage forms. Hierarchical cluster analysis was employed to evaluate the determination results. The results demonstrated that the selection criteria of proton signals established in this work were reliable for the qNMR study of scutellarin in breviscapine preparations.

Anti-Proliferative Effect of Rosmarinus officinalis L. Extract on Human Melanoma A375 Cells

Rosemary (Rosmarinus officinalis L.) has been used since ancient times in traditional medicine, while nowadays various rosemary formulations are increasingly exploited by alternative medicine to cure or prevent a wide range of health disorders. Rosemary’s bioproperties have prompted scientific investigation, which allowed us to ascertain antioxidant, anti-inflammatory, cytostatic, and cytotoxic activities of crude extracts or of pure components. Although there is a growing body of experimental work, information about rosemary’s anticancer properties, such as chemoprotective or anti-proliferative effects on cancer cells, is very poor, especially concerning the mechanism of action. Melanoma is a skin tumor whose diffusion is rapidly increasing in the world and whose malignancy is reinforced by its high resistance to cytotoxic agents; hence the availability of new cytotoxic drugs would be very helpful to improve melanoma prognosis. Here we report on the effect of a rosemary hydroalcoholic extract on the viability of the human melanoma A375 cell line. Main components of rosemary extract were identified by liquid chromatography coupled to tandem mass spectrometry (LC/ESI-MS/MS) and the effect of the crude extract or of pure components on the proliferation of cancer cells was tested by MTT and Trypan blue assays. The effect on cell cycle was investigated by using flow cytometry, and the alteration of the cellular redox state was evaluated by intracellular ROS levels and protein carbonylation analysis. Furthermore, in order to get information about the molecular mechanisms of cytotoxicity, a comparative proteomic investigation was performed.

Investigation on the interactions of scutellarin and scutellarein with bovine serum albumin using spectroscopic and molecular docking techniques

The binding abilities of scutellarin (Scu) and scutellarein (Scue) with bovine serum albumin (BSA) were investigated using equilibrium dialysis, high performance liquid chromatography, fluorescence spectroscopy, competitive site marker and molecular docking. The results showed that the average protein binding ratios of Scu and Scue with BSA were (79.85 ± 1.83) and (85.49 ± 1.21) % respectively. Under simulated physiological conditions, the fluorescence data indicated that Scu and Scue bound with BSA through a static mechanism. The thermodynamic parameters indicated that the interactions of Scu-BSA and Scue-BSA mainly occurred by van der Waals forces and hydrogen bonds and it was easier for Scue to bind with BSA than Scu, indicating that the glucuronic acid molecule in Scu decreased the binding affinity. Site competitive marker experiments showed that the binding sites of Scu and Scue mainly located within the sub-domain IIA of BSA. Furthermore, molecular docking studies indicated that one BSA could bind three Scue, while one BSA could carry only two Scu. All these results clearly indicated the interactions of Scu and Scue with BSA, which will lay the foundation for further research to determine the pharmacology and pharmacodynamics of Scu and Scue for treating ischemic cerebrovascular disease.

Ion suppression; a critical review on causes, evaluation, prevention and applications

The consequences of matrix effects in mass spectrometry analysis are a major issue of concern to analytical chemists. The identification of any ion suppressing (or enhancing) agents caused by sample matrix, solvent or LC-MS system components should be quantified and measures should be taken to eliminate or reduce the problem. Taking account of ion suppression should form part of the optimisation and validation of any quantitative LC-MS method. For example the US Food and Drug Administration has included the evaluation of matrix effects in its "Guidance for Industry on Bioanalytical Method Validation" (F.D.A. Department of Health and Human Services, Guidance for industry on bioanalytical method validation, Fed. Regist. 66 (100) 2001). If ion suppression is not assessed and corrected in an analytical method, the sensitivity of the LC-MS method can be seriously undermined, and it is possible that the target analyte may be undetected even when using very sensitive instrumentation. Sample analysis may be further complicated in cases where there are large sample-to-sample matrix variations (e.g. blood samples from different people can sometimes vary in certain matrix components, shellfish tissue samples sourced from different regions where different phytoplankton food sources are present, etc) and therefore exhibit varying ion-suppression effects. Although it is widely agreed that there is no generic method to overcome ion suppression, the purpose of this review is to: provide an overview of how ion suppression occurs, outline the methodologies used to assess and quantify the impact of ion suppression, discuss the various corrective actions that have been used to eliminate ion suppression in sample analysis, that is to say the deployment of techniques that eliminate or reduce the components in the sample matrix that cause ion suppression. This review article aims to collect together the latest information on the causes of ion suppression in LC-MS analysis and to consider the efficacy of common approaches to eliminate or reduce the problem using relevant examples published in the literature.

A rapid, reproducible, on-the-fly orthogonal array optimization method for targeted protein quantification by LC/MS and its application for accurate and sensitive quantification of carbonyl reductases in human liver

Liquid chromatography (LC)/mass spectrometry (MS) in selected-reactions-monitoring (SRM) mode provides a powerful tool for targeted protein quantification. However, efficient, high-throughput strategies for proper selection of signature peptides (SP) for protein quantification and accurate optimization of their SRM conditions remain elusive. Here we describe an on-the-fly, orthogonal array optimization (OAO) approach that enables rapid, comprehensive, and reproducible SRM optimization of a large number of candidate peptides in a single nanoflow-LC/MS run. With the optimized conditions, many peptide candidates can be evaluated in biological matrixes for selection of the final SP. The OAO strategy employs a systematic experimental design that strategically varies product ions, declustering energy, and collision energy in a cycle of 25 consecutive SRM trials, which accurately reveals the effects of these factors on the signal-to-noise ratio of a candidate peptide and optimizes each. As proof of concept, we developed a highly sensitive, accurate, and reproducible method for the quantification of carbonyl reductases CBR1 and CBR3 in human liver. Candidate peptides were identified by nano-LC/LTQ/Orbitrap, filtered using a stringent set of criteria, and subjected to OAO. After evaluating both sensitivity and stability of the candidates, two SP were selected for quantification of each protein. As a result of the accurate OAO of assay conditions, sensitivities of 80 and 110 amol were achieved for CBR1 and CBR3, respectively. The method was validated and used to quantify the CBRs in 33 human liver samples. The mean level of CBR1 was 93.4 +/- 49.7 (range: 26.2-241) ppm of total protein, and of CBR3 was 7.69 +/- 4.38 (range: 1.26-17.9) ppm. Key observations of this study: (i) evaluation of peptide stability in the target matrix is essential for final selection of the SP; (ii) utilization of two unique SP contributes to high reliability of target protein quantification; (iii) it is beneficial to construct calibration curves using standard proteins of verified concentrations to avoid severe biases that may result if synthesized peptides alone are used. Overall, the OAO method is versatile and adaptable to high-throughput quantification of validated biomarkers identified by proteomic discovery experiments.

Critical topics in ensuring data quality in bioanalytical LC–MS method development

The use of LC–MS for bioanalysis of pharmaceuticals is entering its third decade and may be considered to be a mature technology. In many respects this is true, considering the advances made in such areas as instrument performance, electronics, software and automation of use. However, there remain instrumental and noninstrumental areas that require significant attention to ensure data quality. Increasing regulatory focus on analytical method performance and unaddressed method issues require the bioanalyst to understand those areas that most greatly impact data quality. This review will focus on instrumental and noninstrumental areas that can influence data quality, including reference standard and internal standard quality and physicochemical properties, matrix effects, stability in matrix, sample preparation, LC and MS.

PEG-scutellarin prodrugs: synthesis, water solubility and protective effect on cerebral ischemia/reperfusion injury

Fifteen PEG-scutellarin prodrugs were synthesized by modifying carboxyl and phenolic hydroxyl groups of scutellarin with mPEG of different molecular weight (400-3000). The water solubility of prodrugs increased remarkably and reached the maximum value of 783.88 mg/mL (scutellarin, 0.02 mg/mL). The anti-infarct effects of four PEG prodrugs with high water solubility were evaluated by Cerebral Ischemia/Reperfusion in the Middle Cerebral Artery Occlusion (MCAO) model. The results showed that the prodrug 7e could significantly reduce the infarct area from 27.2% to 12.2% (33.3% for the control) and decrease the neurological deficit score from 2.77 to 1.32 (2.85 for the control). The half-life (18.62 min) of the prodrug 7e was significantly longer than that of scutellarin (3.03 min).

Separation and purification of two flavone glucuronides from Erigeron multiradiatus (Lindl.) Benth with macroporous resins

Scutellarein-7-O-beta-D-glucuronide (SG) and apigenin-7-O-beta-D-glucuronide (AG) are two major bioactive constituents with known pharmacological effects in Erigeron multiradiatus. In this study, a simple method for preparative separation of the two flavone glucuronides was established with macroporous resins. The performance and adsorption characteristics of eight macroporous resins including AB-8, HPD100, HPD450, HPD600, D100, D101, D141, and D160 have been evaluated. The results confirmed that D141 resin offered the best adsorption and desorption capacities and the highest desorption ratio for the two glucuronides among the tested resins. Sorption isotherms were constructed for D141 resin under optimal ethanol conditions and fitted well to the Freundlich and Langmuir models (R(2) > 0.95). Dynamic adsorption and desorption tests was performed on column packed with D141 resin. After one-run treatment with D141 resin, the two-constituent content in the final product was increased from 2.14% and 1.34% in the crude extract of Erigeron multiradiatus to 24.63% and 18.42% in the final products with the recoveries of 82.5% and 85.4%, respectively. The preparative separation of SG and AG can be easily and effectively achieved via adsorption and desorption on D141 resin, and the method developed can be referenced for large-scale separation and purification of flavone glucuronides from herbal raw materials.

Preparation and Pharmacokinetics in Rabbits of Breviscapine Unilamellar Vesicles

The purpose of the study was to prepare the unilamellar liposomal vesicles of breviscapine (Breviscapine-LUVs) and investigate the pharmacokinetics of Breviscapine-LUVs in rabbits. Breviscapine-LUVs were prepared by the film dispersion method and treated further by extrusion. Its size distribution and zeta potential were determined by photon correlation spectroscopy. The encapsulation efficiency (EE) and cumulative release of Breviscapine-LUVs were assayed by the dialysis method. The crossover design (two periods) was used in six rabbits, which were administered Breviscapine-LUVs and reference preparation. Results showed that the particle size of Breviscapine-LUVs was 50.8 nm, and the polydispersity index was 0.287. The zeta potential was -24 mV +/- 9 mV (n = 3), and the EE% was 81.1 +/- 1.1% (n = 3). The cumulative release of vesicles in 0.9% NaCl was 17.2 +/- 0.78%, 26.1 +/- 0.68%, and 29.9 +/- 0.81% in 2, 8, and 24 h, respectively. The mean concentration-time curves of breviscapine liposomes and reference preparation were both fitted to a two-compartment model with the main pharmacokinetic parameters as follows: t(1/2beta) of Breviscapine-LUVs and reference preparation were (42.5 +/- 28.6) min and (6.01 +/- 4.64) min, respectively; CL((s)) were (15.3 +/- 9.03) mL x min(-1) and (84.6 +/- 40.6) mL x min(-1), respectively; AUC(0-300) were (1267 +/- 1083) microg x min x mL(-1) and (196 +/- 107) microg x min x mL(-1), respectively. Compared with the reference preparation, breviscapine liposomes had a much higher concentration in plasma and contained characteristic of sustained-release, which ameliorated the pharmacokinetic properties of scutellarin.

Ultra-sensitive quantification of paclitaxel using selective solid-phase extraction in conjunction with reversed-phase capillary liquid chromatography/tandem mass spectrometry

The ability to quantify ultra-low concentrations of biologically active compounds in biological matrices is essential for the study of pharmacological/toxicological effects occurring at low doses. Selective solid-phase extraction (SPE) was combined with highly sensitive capillary LC (microLC)-MS/MS analysis to achieve ultra-sensitive quantification of the anti-cancer drug paclitaxel in cancer cells. The optimized SPE selectively extracted paclitaxel and eliminated undesirable matrix compounds, thus enabling a high sample loading volume on the microLC column without compromising chromatographic performance and operational robustness. The validated lower limit of quantification (LOQ) was 5pg/mL, approx. 20-fold more sensitive than published LC-MS/MS methods. The calibration curve was linear over the range of 5-6250pg/mL. Accuracy was 98-109% and the variation (CV%) was 2.3-7.4%. This method was applied successfully to quantify temporal drug accumulation by A121a ovarian cancer cells treated with sub-ng/mL concentrations of paclitaxel.

Separation of scutellarin from crude extracts of Erigeron breviscapus (vant.) Hand. Mazz. by macroporous resins

Scutellarin, a flavone glycoside, popularly used in the treatment of heart disease, has been efficiently separated using macroporous resins from crude extracts of Chinese medicinal plant Erigeron breviscapus (vant.) Hand. Mazz. HPD-800 resin offered the best adsorption and desorption capacity for scutellarin among the eight macroporous resins tested, and its adsorption data at 25 degrees C fit best to the Langmuir isotherm. The dynamic adsorption and desorption experiments have been carried out on a HPD-800 resin packed column to optimize the separation process of scutellarin from the crude extracts of E. breviscapus. After one run treatment with HPD-800 resin, the scutellarin content in the product was increased 15.69-fold from 2.61% to 40.96% with a recovery yield of 95.01%. The preparative separation process via adsorption-desorption method developed in this study provides a new approach for scale-up separation and purification of scutellarin for its wide pharmaceutical use.

Characterization of phenolic compounds in Erigeron breviscapus by liquid chromatography coupled to electrospray ionization mass spectrometry

Erigeron breviscapus is an important herbal drug for the treatment of cardiovascular and cerebral vessel diseases. In this study, phenolic compounds were extracted from the whole plant of E. breviscapus and analyzed by high-performance liquid chromatography/electrospray ionization mass spectrometry. A total of 53 compounds were identified or tentatively characterized based on their UV and mass spectra. These compounds included caffeoylquinic acids (CQAs), CQA glucosides, malonyl-CQAs, acetyl-CQAs, caffeoyl-2,7-anhydro-3-deoxy-2-octulopyranosonic acids (CDOAs), caffeoyl-2,7-anhydro-2-octulopyranosonic acids (COAs), flavones, flavonols and flavonones. Most of them were reported for the first time from E. breviscapus and nineteen of them belonged to new compounds. The MS(n) spectra of CQA glucosides were similar to CQAs and they were discriminated by their retention times. No caffeic acid related ions (X(0) (-), Y(0) (-) and Z(0) (-)) were observed in MS(n) spectra of acyl-CQAs compared to those of CQAs. Fragment ions ((2,5)O(-), (3,6)O(-) and (4,6)O(-)) corresponding to ring cleavage were shown in MS(n) spectra of CDOAs and COAs, characteristic of this class of compounds. The 5,6,7-trihydroxyl-substituted flavones were dominant in E. breviscapus. Their [A--H](-) ions underwent the loss of a molecule of H(2)O, followed by the loss of CO, which was used to discriminate from other hydroxyl-substituted flavones. Our results are the first comprehensive analysis of E. breviscapus constituents and will be helpful for the quality control of the herb of E. breviscapus and its related preparations.

Two-step purification of scutellarin from Erigeron breviscapus (vant.) Hand. Mazz. by high-speed counter-current chromatography

Scutellarin, a flavone glycoside, popularly applied for the treatment of cardiopathy, has been purified in two-step purification by high-speed counter-current chromatography (HSCCC) from Erigeron breviscapus (vant.) Hand. Mazz. (Deng-zhan-hua in Chinese), a well-known traditional Chinese medicinal plant for heart disease. Two solvent systems, n-hexane-ethyl acetate-methanol-acetic acid-water (1:6:1.5:1:4, v/v/v/v/v) and ethyl acetate-n-butanol-acetonitrile-0.1% HCl (5:2:5:10, v/v/v/v) were used for the two-step purification. The purity of the collected fraction of scutellarin was 95.6%. This study supplies a new alternative method for purification of scutellarin.

An approach to develop two-dimensional fingerprint for the quality control of Qingkailing injection by high-performance liquid chromatography with diode array detection

An approach was proposed to develop two-dimensional fingerprint (2D fingerprint) by means of principal component analysis (PCA) of high-performance liquid chromatography with diode array detection (HPLC/DAD) data. The approach was applied to establish 2D fingerprints of various Qingkailing injections which were produced by different manufacturers and procedures. In comparison with common one-dimensional fingerprint (ID fingerprint) at fixed wavelength, 2D fingerprint compiled additional spectral data and was hence more informative. Principal component analysis of the 2D fingerprint data was performed in this study, and it led to an accurate classification of various samples on their manufacturers and procedures. The quality of Qingkailing samples was further evaluated by similarity measures and the same results were achieved. For comparison, four conventional ID fingerprints were also applied to the quality assessment for the same samples. Finally, we demonstrated that 2D fingerprint was a more powerful tool to characterize the quality of samples, and could be used to comprehensively conduct the quality control of traditional Chinese medicines.

Rapid and reliable determination of illegal adulterant in herbal medicines and dietary supplements by LC/MS/MS

In recent years, dietary supplements and herbal medicines are increasing in popularity all over the world. However, it is problematic that some manufacturers illegally included synthetic drugs in their products. Due to the extremely complex matrices of those products, most existing methods for screening illegal adulterations are time-consuming and liable to false positive. In this paper, a robust LC/MS/MS method for the high-throughput, sensitive and reliable determination of illegal adulterations from herbal medicines and dietary supplements was established. Minimal LC separation was employed and MRM was used to simultaneously monitor the three transitions under their respective optimal collision energy for each compound. Positive results were determined only if well-defined peaks appeared at all of the three transitions and the ratios among the peak areas were within given threshold. In this study, the method had been applied for the screening of nine most commonly adulterated therapeutic substances, such as sildenafil (Viagra) and famotidine, and the lower limits of detection of these compounds ranged from 0.05 to 1.5 ng/ml. Little sample preparation was needed for this method and the analysis time was less than 5 min/sample. The reliability has been demonstrated by the test with blank matrix. Over 200 products that were under suspicion by SDA of China had been assayed and till now no false negative or positive result was found. This method is rapid, simple, reliable and capable of screening multiple adulterants in one run.

A study of matrix effects on an LC/MS/MS assay for olanzapine and desmethyl olanzapine

The purpose of this research project was to investigate potential matrix effects of anticoagulant and lipemia on the response of olanzapine, desmethyl olanzapine, olanzapine-D(3) and desmethyl olanzapine-D(8) in an LC/MS/MS assay. Blank human serum and sodium heparin, sodium citrate, and K(3)EDTA plasma with various degrees of lipemia were fortified with olanzapine, desmethyl olanzapine, olanzapine-D(3) and desmethyl olanzapine-D(8). Six replicates of each sample were extracted using Waters Oasis MCX cartridges and analyzed using electrospray LC/MS/MS. The analytes were separated on a Phenomenex LUNA phenyl hexyl, 2 mm x 50 mm, 5 microm, analytical column and a gradient rising from 2 to 85% mobile phase B. Mobile phase A consisted of acetonitrile-ammonium acetate (20 mM) (52:48 v/v) and mobile phase B was formic acid-acetonitrile (0.1:100 v/v). Ion suppression was investigated through post column infusion experiments. The degree of lipemia of each sample, indicated by turbidity, was ranked into categories from least to greatest and used for statistical analyses. The results from analysis of variance testing indicated that lipemia, anticoagulant and their interaction significantly influenced mass spectral matrix effects and extraction matrix effects. Differential behavior between the analytes and labeled internal standards contributed to variability. The most significant source of variability however, was ion suppression due to co-eluting matrix components.

Simultaneous determination of active ingredients in Erigeron breviscapus (Vant.) Hand-Mazz. by capillary electrophoresis with electrochemical detection

A high-performance capillary electrophoresis (CE) with electrochemical detection (ED) method was developed for the determination of the pharmacologically active ingredients in Erigeron breviscapus (Vant.) Hand-Mazz. and its extract phytopharmaceuticals in this work. Under the optimum conditions, nine analytes, baicalein, naringenin, scopoletin, kaempferol, apigenin, scutellarin, luteolin, caffeic acid and protocatechuic acid were separated within 24 min in a borax buffer (pH 8.7). Notably, excellent linearity was obtained over two orders of magnitude with detection limits (S/N=3) ranged from 1.0 x 10(-7) g/mL to 5.6 x 10(-7) g/mL for all nine analytes. This method was successfully used in the analysis of E. breviscapus (Vant.) Hand-Mazz. and its phytopharmaceuticals with a relatively simple extraction procedure, and the assay results were satisfactory.

Adsorption and Desorption Properties of trans-Resveratrol on Cellulose Cotton

The adsorption and desorption properties of trans-Resveratrol (Res) on the cellulose cotton were investigated under various conditions, such as the pH, alcohol percentage, temperature and equilibrium times. Moreover, the acidic-dissociation constants were determined to be pKa1 = 8.01, pKa2 = 9.86 and pKa3 = 10.5 by a curve-fitting method. Also, it was found that the adsorption depended on the temperature and salting effect. On the other hand, the desorptions from cellulose were examined using several kinds of water-miscible organic solvents (methanol, ethanol, acetone and THF).

Ion-pairing reversed-phase liquid chromatography/electrospray ionization mass spectrometric analysis of 76 underivatized amino acids of biological interest: a new tool for the diagnosis of inherited disorders of amino acid metabolism

Seventy-six molecules of biological interest for the diagnosis of inherited disorders of amino acids (AA) metabolism have previously been demonstrated to be detectable in electrospray ionization tandem mass spectrometry (ESI-MS/MS) positive mode without derivatization. Reversed-phase liquid chromatography (RPLC) separation on different C18 columns using various perfluorinated carboxylic acids as ion-pairing agents has been found suitable for coupling with MS/MS, and for the separation of AA. A new procedure was optimized in order to replace the usual ion-exchange chromatographic, post-column ninhydrin derivatization, time-consuming routine method. This procedure allowed an adequate separation of all the molecules from other known interfering compounds, and a throughput of two samples per hour. Quantification limits for each molecule were found to be compatible with their measurement in plasma and urine. We validated the qualitative part of the method by analyzing plasma and urine samples from patients affected with several inherited disorders of AA metabolism. We validated the quantification of 16 AA using their stable isotopes as internal standard. The calibration curves were linear over the range 0-3 mM. The quantitative results obtained with the new method on 105 plasma and 99 urine samples were in good agreement with those obtained by the established routine method. Spiking experiments and precision results were also satisfactory.

Determination of scutellarin in rat plasma by high-performance liquid chromatography with ultraviolet detection

A validated high-performance liquid chromatography method is described for the determination of scutellarin in rat plasma using a liquid-liquid extraction and ultraviolet (UV) absorbance detection. The separation used a Diamonsil ODS column (250 mm x 4.6mm i.d., 5 microm particle size) with an isocratic mobile phase consisting of methanol-acetonitrile-50mM dihydrogen ammonium phosphate buffer (22:15:63 (v/v/v), adjusted to pH 2.5 with 1M phosphoric acid). The ultraviolet detector operated at 335 nm. Plasma samples were extracted with ethyl acetate after acidification. The extraction recovery of scutellarin ranged from 68.1 to 80.5%. High selectivity and a low quantitation limit (0.050 microg/ml) were achieved. The linear range was 0.050-12.5 microg/ml, correlation coefficient r=0.9981. The method has a good reproducibility, R.S.D. values were below 7.9% for within-day and between-day precision. The method is simple, rapid, and applicable to preliminary pharmacokinetic studies of scutellarin in rats.

Matrix effects in (ultra)trace analysis of pesticide residues in food and biotic matrices

If one has to determine multiple residues of modem pesticides and/or other groups of (semi)polar and/or thermally unstable contaminants with a wide range of physico-chemical properties within a single analytical run, it can be complicated to obtain low limits of quantitation (LOQ), good precision as well as relevant trueness of results for all the target analytes. Matrix components, which are unavoidably present in analyzed samples (even after the thorough clean-up step), may be responsible for miscellaneous adverse affects impairing different stages of the GC and/or LC determinative step. In this review, the nature of various types of matrix effects are discussed together with suggestions for prevention, reduction and/or compensation of their occurrence when determining troublesome analytes in foods and other complex biotic matrices.

Identification and determination of glucuronides and their aglycones in Erigeron breviscapus by liquid chromatography-tandem mass spectrometry

A novel, speedy and reliable LC-MS-MS method for the search, identification and quantitation of O-glycosides and their aglycones from plant resources was established by analyzing the extract of Erigeron breviscapus. The extract was directly infused to a triple-quadrupole MS-MS and major glucuronides in the extract were screened out with high confidence by a neutral loss scan for the loss of a gluconic acid. The identity of these glucuronides and their aglycones was further confirmed with LC-MS-MS. In addition to scutellarin, apigenin 7-O-glucuronide, quercetin-3-O-glucuronide and their aglycones that were previously reported by others, we also confirmed by LC-MS-MS that remarkable amount of baicalin, an isomer of apigenin 7-O-glucuronide, presented in the extract of this plant, which had not been reported before. A satisfying quantitation of three glucuronides was also made by LC-MS-MS.