Determination of Aconitum alkaloids in blood and urine samples. I. High-performance liquid chromatographic separation, solid-phase extraction and mass spectrometric confirmation

Plant Poisons in the Garden: A Human Risk Assessment

A study of the plants, and their associated poisons, in the Poison Garden at The Alnwick Garden was undertaken across a calendar year. By selecting 25 plants in the Poison Garden, we have been able to develop a single chromatographic method for the determination and quantification of 15 plant toxins by liquid chromatography mass spectrometry (LC-MS). Chromatographic separation was achieved on a C18 column (3.5 µm, 100 × 4.6 mm) with a gradient method using water +0.1% formic acid and methanol +0.1% formic acid. The developed method was validated for precision, linearity, limits of detection and quantification and extraction recoveries. The method showed good linearity with a R2 value of >0.995 for all 15 compounds with good precision of 10.7%, 6.7% and 0.3% for the low, medium and high calibration points, respectively. The LC-MS method was used to analyse 25 plant species, as well as their respective parts (i.e., bulb, flower, fruit, leaf, pollen, seed, stem and root), to assess the human risk assessment to children (aged 1 to <2 years) in relation to the plant toxin and its respective LD50. The analysis found that the greatest potential health risks were due to the ingestion of Colchicum autumnale and Atropa belladonna. As a caution, all identified plants should be handled with care with additional precautionary steps to ensure nil contact by children because of the potential likelihood of hand-to-mouth ingestion.

Clinical relationship between blood concentration and clinical symptoms in aconitine intoxication

BACKGROUND

Aconitine is well-known for its potential analgesic, anti-inflammatory, and circulation promoting effects and has been widely used as a folk medicine in South Korea. Owing to its extremely toxic nature and relatively low safety margin, intoxication is sometimes fatal. The toxic compound mainly affects the central nervous system, heart, and muscle, resulting in cardiovascular complications.

PURPOSE

To determine the exact relationship between blood concentration of aconitine and clinical manifestation.

BASIC PROCEDURES

The National Forensic Service (NFS) was commissioned to assist in a quantitative analysis of highly toxic aconitine and corresponding blood concentrations by analyzing the body fluids of three patients who were suspected of aconitine poisoning.

MAIN FINDINGS

Aconitine blood values tested by the NFS showed that patients with a blood concentration below a certain level developed symptoms slowly and showed a high severity of clinical manifestation. There was no correlation between blood concentration and symptoms or ECG results.

CONCLUSIONS

In case of suspected aconitine poisoning, an emergency care department should be visited, even with symptomatic improvement, and the patient should be monitored for at least 24 h, depending on the level of recovery and changes in ECG results.

Optimization of the traditional processing method for precision detoxification of CaoWu through biomimetic linking kinetics and human toxicokinetics of aconitine as toxic target marker

ETHNOPHARMACOLOGICAL RELEVANCE

CaoWu (Aconiti Kusnezoffii Radix), well known for its high toxicity leading to fatal ventricular arrhythmias, is detoxified by HeZi (Terminalia Chebula Retz) decoction to prepare ZhiCaoWu (Aconiti Kusnezoffii Radix Preparata) as one part of ingredients of NaRu-3 pill which is used for the treatment of rheumatoid arthritis (RA). Aconitine (AC) is a highly toxic alkaloid of CaoWu and it is used as toxic target marker for the quality control (QC) of ZhiCaoWu. In the traditional processing method, the vanish of astringent or spicy feeling in tongue is the important detoxification indicator of ZhiCaoWu. However, how CaoWu is detoxified to ZhiCaoWu and whether the appropriate content of AC in ZhiCaoWu can be efficiently perceived after the empirical detoxification still lack factual basis.

AIM OF THE STUDY

The present study aimed to optimize the traditional processing method for precision detoxification of CaoWu through biomimetic linking kinetics and human toxicokinetics (TK) of AC, with a view of providing insights into the changes of toxic target marker.

MATERIALS AND METHODS

CaoWu medicinal slices (Mes) and coarse powder (Cop) were processed by blank HeZi decoction through the soaking method for 7 days. High-performance liquid chromatography (HPLC) was used for the analysis of the samples. The acidity of blank HeZi decoction and HeZi processing decoction was directly determined by pH meter. The non-compartment analysis (NCA) was used to have an intuitive appreciation for AC and pH changes in HeZi processing decoction while the compartment model method was used to build the biomimetic linking kinetics model with the covariate. The inter-species scaling of animal TK parameters was conducted to predict human AC TK profiles. The possible uptake ways of AC (rapid-release or extended-release) for humans were attempted to assess the poisoning risk of AC in NaRu-3 pill. Based on the target content of AC in ZhiCaoWu, the biomimetic linking kinetics model was explored to optimize the traditional processing detoxification method of CaoWu. The assays of determining inflammatory cytokines in lipopolysaccharides (LPS)-induced RAW264.7 cells were performed to investigate the inflammatory modulation effects of AC in vitro.

RESULTS

ZhiCaoWu was prepared by eliminating redundant AC in CaoWu through the repeatable replacement of HeZi processing decoction in which its acidity (pH) was affected. AC-pH changes in HeZi processing decoction were adequately depicted by a biomimetic linking kinetics model whose predictive power was determined by comparing the predictions of AC in ZhiCaoWu with the reported data. Rapid-release AC at the converted dose of 111.1 and 417.6 μg (0.011 and 0.042% of AC in NaRu-3 pill) reached maximum blood concentrations of 26.1 and 98.1 ng/mL at 0.3 h, in comparison with minimum human lethal concentration (100 ng/mL). Achieving the target content of AC (0.04%) in ZhiCaoWu or AC (0.011%) in NaRu-3 pill to precisely control the poisoning risk, the potential optimized protocols were that the processing time at 0.2-0.8% of AC in CaoWu was 2.0-4.4 days for Cop and 2.7-6.2 days for Mes. Correspondingly, pH values in HeZi processing decoction were 3.95 and 3.77 for Cop and Mes, respectively. Meanwhile, Lipopolysaccharides (LPS)-induced RAW264.7 cells were exposed to 0, 20, and 200 μM of AC for 12 h and AC at 20 μM enhanced the levels of IL-6, IL-10 and TNF-α.

CONCLUSIONS

Thus, for the first time, a biomimetic linking kinetics model was built to optimize the traditional detoxification method. Moreover, pH changes could be developed as surrogate endpoint for guiding the processing detoxification of CaoWu. Notably, setting the content limit of AC (0.011%) was very rational to control the poisoning risk of NaRu-3 pill. In addition, it was possible that there existed the more complex mechanisms of AC for inflammatory modulation in vitro.

Non-thermal plasma treatment of Radix aconiti wastewater generated by traditional Chinese medicine processing

The wastewater effluent from Radix aconiti processing, an important step in the production processes of traditional Chinese medicine (TCM), is a type of toxic wastewater and difficult to treat. Plasma oxidation methods have emerged as feasible techniques for effective decomposition of toxic organic pollutants. This study examined the performance of a plasma reactor operated in a dielectric barrier discharge (DBD) to degrade the effluent from R. aconiti processing. The effects of treatment time, discharge voltage, initial pH value and the feeding gas for the reactor on the degradation of this TCM wastewater were investigated. A bacterium bioluminescence assay was adopted in this study to test the toxicity of the TCM wastewater after non-thermal plasma treatment. The degradation ratio of the main toxic component was 87.77% after 60min treatment with oxygen used as feed gas and it was 99.59% when the initial pH value was 8.0. High discharge voltage and alkaline solution environment were beneficial for improving the degradation ratio. The treatment process was found to be capable of reducing the toxicity of the wastewater to a low level or even render it non-toxic. These experimental results suggested that the DBD plasma method may be a competitive technology for primary decomposition of biologically undegradable toxic organic pollutants in TCM wastewater.

A review on phytochemistry, pharmacology and toxicology studies of Aconitum

Objectives

A number of species belonging to herbal genus Aconitum are well-known and popular for their medicinal benefits in Indian, Vietnamese, Korean, Japanese, Tibetan and Chinese systems of medicine. It is a valuable drug as well as an unpredictable toxic material. It is therefore imperative to understand and control the toxic potential of herbs from this genus. In this review, the ethnomedicinal, phytochemistry, pharmacology, structure activity relationship and toxicology studies of Aconitum were presented to add to knowledge for their safe application.

Key findings

A total of about 76 of all aconite species growing in China and surrounding far-east and Asian countries are used for various medical purposes. The main ingredients of aconite species are alkaloids, flavonoids, free fatty acids and polysaccharides. The tuberous roots of genus Aconitum are commonly applied for various diseases such as rheumatic fever, painful joints and some endocrinal disorders. It stimulates the tip of sensory nerve fibres. These tubers of Aconitum are used in the herbal medicines only after processing. There remain high toxicological risks of the improper medicinal applications of Aconitum. The cardio and neurotoxicities of this herb are potentially lethal. Many analytical methods have been reported for quantitatively and qualitatively characterization of Aconitum.

Summary

Aconitum is a plant of great importance both in traditional medicine in general and in TCM in particular. Much attention should be put on Aconitum because of its narrow therapeutic range. However, Aconitum's toxicity can be reduced using different techniques and then benefit from its pharmacological activities. New methods, approaches and techniques should be developed for chemical and toxicological analysis to improve its quality and safety.

Pharmacokinetics of aconitine as the targeted marker of Fuzi (Aconitum carmichaeli) following single and multiple oral administrations of Fuzi extracts in rat by UPLC/MS/MS

ETHNOPHARMACOLOGICAL RELEVANCE

Fuzi, which is the processed lateral roots of Aconitum Carmichaeli. Debx and is widely distributed over the southwest provinces of China, is recognised for its anti-inflammatory and analgesic effects.

AIM OF THE STUDY

The pharmacokinetic properties of Fuzi are inadequately understood. Aconitine, the primary highly toxic ingredient of Fuzi, is well known as the target marker of Fuzi. The purpose of the present study is to investigate the pharmacokinetic behaviours of aconitine in vivo following single and multiple administrations of processed Fuzi extracts and to compare the pharmacokinetic characteristics of aconitine after administrations of pure aconitine or Fuzi extracts as well as compare the difference at single dose and multiple doses. The in vitro aconitine protein binding in plasma through equilibrium dialysis was also examined.

METHODS

A high performance liquid chromatography (HPLC) method was developed for the determination of aconitine in Fuzi crude extracts and a fast ultra performance liquid chromatography-tandem mass spectrometry (UPLC/MS/MS) was developed to investigate the pharmacokinetic behaviour of aconitine as the targeted marker of Fuzi.

RESULTS

The absolute bioavailability (F %) after the administration of 0.5 mg/kg aconitine and Fuzi extract (0.118 mg/kg aconitine) in rat was 8.24±2.52% and 4.72±2.66%, respectively. Aconitine absorption was very fast at the t(max) 30.08±9.73 min for pure aconitine and 58.00±21.68 min for Fuzi extract administration. Aconitine was also eliminated rapidly with a short half-life (i.v., 80.98±6.40 min) and a low rate of protein bounding (23.9-31.9%). No significance was observed on all the pharmacokinetics parameters following the single and multiple doses of pure aconitine (ANOVA, p>0.05). However, the absorption of aconitine after multiple administrations of Fuzi extract was much faster than that of a single dose (t(max): 58.00±21.68 vs. 20.00±8.66 min, p<0.05), and the area under the plasma concentration-time curve (AUC) was higher than that of a single dose.

CONCLUSIONS

The pharmacokinetic behaviour of processed Fuzi was determined in this paper. The aconitine has low bioavailability. No variation in the pharmacokinetic behaviours of pure aconitine was observed after single and multiple administrations. In contrast, multiple administrations of processed Fuzi extract could result in variations in its pharmacokinetic behaviour in AUC and t(max) indicating that multiple dose might increase the bioavailability of aconitine, which may result in its toxicity. In addition, aconitine has a low protein bounding (23.9-31.9%), resulting in its rapid elimination.

Development and validation of a highly sensitive UPLC-MS/MS method for simultaneous determination of aconitine, mesaconitine, hypaconitine, and five of their metabolites in rat blood and its application to a pharmacokinetics study of aconitine, mesaconitine, and hypaconitine

A rapid, specific and sensitive method was developed for the simultaneous determination of eight Aconitum alkaloids: aconitine (AC), mesaconitine (MA), hypaconitine (HA), benzoylaconine (BAC), benzoylmesaconine (BMA), benzoylhypaconine (BHA), aconine and mesaconine in rat blood by ultra-performance liquid chromatography coupled tandem mass spectrometry (UPLC-MS/MS). The UPLC-MS/MS system coupled with an electrospray ionization (ESI) source was operated in a positive mode via multiple-reaction monitoring (MRM). Samples were treated with methanol to remove protein prior to analysis by UPLC-MS/MS. The analytes were separated with a Waters C18 column (1.7 µm, 50 × 2.1 mm) and a gradient elution using acetonitrile and 0.1% formic acid-water as the mobile phases. The linear response range was from 0.125 to 1000 nmol/L for these eight alkaloids and the correlation coefficients (r(2) values) were all higher than 0.997. The method was validated with respect to precision, accuracy, recovery, matrix effect, carryover effect and sample stability, and found to be within the acceptable limits. The developed and validated method was successfully applied to simultaneously determine the eight Aconitum alkaloids in rats blood after intravenous administration of a mixture of AC, MA and HA.

Aconitum lipo-alkaloids – Semisynthetic Products of the Traditional Medicine

The term lipo-alkaloid is used for C19 aconitane alkaloids containing one or two long-chain fatty acid residues. Lipo-alkaloids are transesterified derivatives of the most toxic and highly effective diester-type diterpene alkaloids, such as aconitine, hypaconitine, mesaconitine. Lipo-alkaloids are native minor compounds of aconite drugs, but their amount significantly increases after traditional processing, which is a general method in the Far Eastern traditional medicinal systems. Analytical works demonstrated that cautious processing (usually boiling) of crude aconite roots decreases the amount of normal diterpene alkaloids and increases the concentration of lipo-alkaloids resulting in the reduction of toxicity of the drugs. Many papers reported that lipo-alkaloids occur as a complex mixture in the drugs, and the isolation of the individual components is extremely difficult. These compounds have been identified using highly sensitive analytical methods (HPLC-MS, NMR), and semisynthetic approaches have been developed to ensure lipo-alkaloids in pure form for pharmacological studies.

This review summarizes the structure, chemistry, semisynthesis, analytics and bioactivities of lipo-alkaloids. On the basis of 32 references this is the first comprehensive study on this topic, covering the data of 173 compounds.

Involvement of CYP3A4/5 and CYP2D6 in the metabolism of aconitine using human liver microsomes and recombinant CYP450 enzymes

Aconitine (AC), a famous major Aconitum alkaloid, has effective antirheumatic function with high toxicity. The aim of our study was to in-depth investigate cytochrome P450 isozymes (CYPs) involved in aconitine metabolism in vitro. We used human liver microsomes (HLMs) as well as recombinant CYPs to investigate the metabolism pathways of aconitine by liquid chromatography-tandem mass spectrometry. Fluvoxamine maleate, gemfibrozil, amiodarone hydrochloride, omeprazole, quinidine, diethyldithiocarbamic acid and ketoconazole were successfully applied as test inhibitors for CYP1A2, CYP2C8, CYP2C9, CYP2C19*1, CYP2D6*1, CYP2E1 and CYP3A4/5 in HLMs, respectively. Six CYP-mediated metabolites were found and characterized in human liver microsomes and eight recombinant CYP isoforms. The inhibitor of CYP 3A had a strong inhibitory effect, the inhibitors of CYP 2C9, 2C8 and CYP2D6 had little inhibitory effects, whereas CYP2C19, 1A2 and 2E1 had no obvious inhibitory effects on AC metabolism. Hydroxylation and di-demethylation of aconitine were conducted by human recombinant CYP 3A5 and 2D6, dehydrogenation was only processed by CYP3A4/5, and the main CYP isoforms metabolizing aconitine to demethyl-aconitine and N-deethyl-aconitine were CYP3A4/5 and CYP2D6. In conclusion, aconitine can be transformed into at least six CYP-mediated metabolites in HLMs, CYP 3A4/5 and 2D6 were the most important CYP isoforms responsible for the de-methylation, N-deethylation, dehydrogenation, and hydroxylation of aconitine.

Diterpenoid alkaloids

The lasting attention that researchers have devoted to diterpenoid alkaloids is due to their various bioactivities and toxicities, structural complexity, and intriguing chemistry. From 1998 to the end of 2008, more than 300 new diterpenoid alkaloids were isolated from Nature. This review focuses on their structural relationships, and investigations into their chemical reactions, synthesis, and biological activities. A table that lists the names, plant sources, and structural types is given along with 363 references.

Aconitum in traditional Chinese medicine: a valuable drug or an unpredictable risk?

Aconitum species have been used in China as an essential drug in Traditional Chinese Medicine (TCM) for 2000 years. Reviewing the clinical application of Aconitum, their pharmacological effects, toxicity and detoxifying measures, herb-herb interactions, clinical taboos, famous herbal formulas, traditional and current herbal processing methods based upon a wide range of literature investigations serve as a case study to explore the multidisciplinary implications of botanicals used in TCM. The toxicological risk of improper usage of Aconitum remains very high, especially in countries like China, India and Japan. The toxicity of Aconitum mainly derives from the diester diterpene alkaloids (DDAs) including aconitine (AC), mesaconitine (MA) and hypaconitine (HA). They can be decomposed into less or non-toxic derivatives through Chinese traditional processing methods (Paozhi), which play an essential role in detoxification. Using Paozhi, the three main forms of processed aconite -- yanfuzi, heishunpian and baifupian -- can be obtained (CPCommission, 2005). Moreover, some new processing techniques have been developed in China such as pressure-steaming. The current development of fingerprint assays, in particular HPLC, has set a good basis to conduct an appropriate quality control for TCM crude herbs and their ready-made products. Therefore, a stipulation for a maximum level of DDA content of Aconitum is highly desirable in order to guarantee the clinical safety and its low toxicity in decoctions. Newly developed HPLC methods have made the accurate and simultaneous determination and quantification of DDA content interesting.

Structural characterization and identification of C(19)- and C(20)-diterpenoid alkaloids in roots of Aconitum carmichaeli by rapid-resolution liquid chromatography coupled with time-of-flight mass spectrometry

Aconite alkaloids from the roots of Aconitum carmichaeli (Fuzi, in Chinese) have been investigated by rapid-resolution liquid chromatography coupled with time-of-flight mass spectrometry (TOFMS) in positive mode. With dynamic adjustment of the key role as fragmentor voltage in TOFMS, an efficient transmission of the ions was achieved to obtain the best sensitivity for providing the molecular formula for each analyte, and abundant fragment ions for structural information. Fifteen authentic standards isolated from Fuzi with various structures were first characterized by TOFMS, including diester-diterpenoid alkaloids (DDAs), monoester-diterpenoid alkaloids (MDAs), alkylol amine-diterpenoid alkaloids (ADAs), veatchine-type alkaloids and atisine-type alkaloids. Fragmentation rules and key diagnostic fragment ions have been summarized, and possible pathways of fragmentation have been proposed. By accurate mass measurements within 5 ppm error for each ion, 30 C(19)-diterpenoid alkaloids including 10 DDAs, 3 MDAs, 9 ADAs and 8 other type alkaloids, and 8 C(20)-diterpenoid alkaloids including 4 veatchine-type alkaloids and 4 atisine-type alkaloids could be identified in a methanolic extract of Fuzi. Some isomers of aconite alkaloids were also differentiated. Based on the differences between their fragmentation pathways and special fragment ions, each type of aconite alkaloids was differentiated.

Determination of aconitine-type alkaloids as markers in fuzi (Aconitum carmichaeli) by LC/(+)ESI/MS(3)

LC/(+)ESI/MS(3) was used to determine aconitine, mesaconitine, and hypaconitine as target markers in crude methanol extracts of (i) the raw lateral roots of Aconitum carmichaeli, (ii) roots treated by three different refining processes, and (iii) eight generally available traditional Chinese medicine (TCM) preparations containing fuzi (treated lateral roots of A. carmichaeli). The optimal ionization behavior resulted when using electrospray ionization (ESI) in positive-ion mode with 0.005% TFA as an additive in the mobile phase. The consecutive reaction monitoring (CRM) mode provided additional improvements in selectivity, which was exploited to minimize the noise and interference problems. Employing this approach, aconitine and mesaconitine were found to decompose readily during the refining processes, but hypaconitine remains present at the same content, presumably because of its characteristic chemical structure. Thus, treated and untreated fuzi samples can be distinguished by monitoring the ratio of aconitine and mesaconitine to hypaconitine. The limits of detection (LODs) for these three markers were 0.05, 0.08, and 0.03 ng/ml. The linearity range for the three marker compounds was 0.1-1,000 ng/ml. The analysis time was 12 min per sample.

[Simultaneous determination of aconitine analogues in Aconitum plants and foods that caused food poisoning by liquid chromatography with tandem mass spectrometry]

A simple method for the simultaneous determination of four aconitine analogues (AC; aconitine, HA; hypaconitine, MA; mesaconitine, JA; jesaconitine) in Aconitum plants (Aconitum subcuneatum NAKAI) and a food that caused food poisoning was developed, using liquid chromatography tandem mass spectrometry (LC/MS/MS). Aconitine analogues were extracted with 1 mmol/L HCl and then cleaned up with an Oasis HLB cartridge. The LC separation was performed with an octadecylated silica column (Develosil ODS-HG-5, 2.0 mm i.d. x 50 mm) at a flow rate of 0.2 mL/min, using A solution (5 mmol/L ammonium acetate dissolved in 0.1% acetic acid) and B solution (acetonitrile-THF=1 : 3), 90%A (0 min)-->60%A (15 min)-->const. (2 min). Mass spectral acquisition was performed in the positive mode and the analogues were targeted using multiple reaction monitoring (MRM) with electrospray ionization (ESI). The recoveries of aconitine analogues were 93-99% from Aconitum plants. The detection limits of AC, HA, MA and JA were 0.4, 0.4, 0.3 and 0.5 ng/g, respectively. The aconitine analogues, except JA, were detected in food that caused food poisoning at the level of 2.6-29.7 microg/g. These results indicate that the developed method is suitable for the determination of aconitine analogues in Aconitum plants and foods that cause food poisoning.

Microchip micellar electrokinetic chromatography separation of alkaloids with UV-absorbance spectral detection

A microchip device is demonstrated for the electrophoretic separation and UV-absorbance spectral detection of four toxic alkaloids: colchicine, aconitine, strychnine, and nicotine. A fused-silica (quartz) microchip containing a simple cross geometry is utilized to perform the separations, and a miniature, fiber-optic CCD spectrometer is coupled to the microchip for detection. Sensitive UV-absorbance detection is achieved via the application of online preconcentration techniques in combination with the quartz microchip substrate which contains an etched bubble-cell for increased pathlength. The miniature CCD spectrometer is configured to detect light between 190 and 645 nm and LabView programming written in-house enables absorbance spectra as well as separations to be monitored from 210 to 400 nm. Consequently, the configuration of this microchip device facilitates qualitative and quantitative separations via simultaneous spatial and spectral resolution of solutes. UV-absorbance limits of quantification for colchicine, 20 microM (8 mg/L); strychnine, 50 microM (17 mg/L); aconitine, 50 microM (32 mg/L); and nicotine, 100 microM (16 mg/L) are demonstrated on the microchip. With the exception of aconitine, these concentrations are > or =20-times more sensitive than lethal dose monitoring requirements. Finally, this device is demonstrated to successfully detect each toxin in water, skim milk, and apple juice samples spiked at sublethal dose concentrations after a simple, SPE procedure.

An optimized high-performance liquid chromatography (HPLC) method for benzoylmesaconine determination in Radix Aconiti Lateralis Preparata (Fuzi, aconite roots) and its products

Background

Benzoylmesaconine (BMA) is the main Aconitum alkaloid in Radix Aconiti Lateralis Preparata (Fuzi, aconite roots) with potent pharmacological activities, such as analgesia and anti-inflammation. The present study developed a simple and reliable method using BMA as a marker compound for the quality control of processed aconite roots and their products.

Methods

After extraction, a high-performance liquid chromatography (HPLC) determination of BMA was conducted on a RP-C₁₈ column by gradient elution with acetonitrile and aqueous phase, containing 0.1% phosphoric acid adjusted with triethylamine to pH 3.0.

Results

A distinct peak profile was obtained and separation of BMA was achieved. Method validation showed that the relative standard deviations (RSDs) of the precision of BMA in all intra-day and inter-day assays were less than 1.36%, and that the average recovery rate was 96.95%. Quantitative analysis of BMA showed that the content of BMA varied significantly in processed aconite roots and their products.

Conclusion

This HPLC method using BMA as a marker compound is applicable to the quality control of processed aconite roots and their products.

Simultaneous determination of three aconitum alkaloids in urine by LC-MS-MS

A sensitive method has been developed for the identification and quantification of the toxic alkaloids yunaconitine, crassicauline A, and foresaconitine in urine specimens. After solid-phase extraction using Oasis MCX cartridges, the extracts were analyzed by LC-MS-MS. The limit of detection is 0.03 ng/mL urine for yunaconitine and 0.05 ng/mL urine for crassicauline A and foresaconitine; the limit of quantitation is 0.15 ng/mL urine for yunaconitine and 0.20 ng/mL urine for crassicauline A and foresaconitine. The method was employed in the analysis of the urine of a 55-year-old male who died after ingestion of herbal medicine powder made from the roots of aconite. Yunaconitine, crassicauline A and foresaconitine were identified in the urine. Crassicauline A and foresaconitine were thus identified in a biological specimen for the first time.

Application of high performance capillary electrophoresis on toxic alkaloids analysis

We employed CE to identify mixtures of the toxic alkaloids lappaconitine, bullatine A, atropine sulfate, atropine methobromide, scopolamine hydrobromide, anisodamine hydrobromide, brucine, strychnine, quinine sulfate, and chloroquine in human blood and urine, using procaine hydrochloride as an internal standard. The separation employed a fused-silica capillary of 75 microm id x 60 cm length (effective length: 50.2 cm) and a buffer containing 100 mM phosphate and 5% ACN (pH 4.0). The sample was injected in a pressure mode and the separation was performed at a voltage of 16 kV and a temperature of 25 degrees C. The compounds were detected by UV absorbance at wavelengths of 195 and 235 nm. All the ten alkaloids were separated within 16 min. The method was validated with regard to precision (RSD), accuracy, sensitivity, linear range, LOD, and LOQ. In blood and urine samples, the detection limits were 5-40 ng/mL and linear calibration curves were obtained over the range of 0.02-10 microg/mL. The precision of intra- and interday measurements was less than 15%. Electrophoretic peaks could be identified either by the relative migration time or by their UV spectrum.

Facile separation and determination ofAconitine alkaloids in traditional Chinese medicines by CE with tris(2,2'-bipyridyl) ruthenium(II)-based electrochemiluminescence detection

A facile CE method coupled with tris(2,2'-bipyridyl) ruthenium(II)-based electrochemiluminescence [Ru(bpy)(3) (2+)] detection was developed for simultaneous determination of Aconitum alkaloids, i.e., hypaconitine (HA), aconitine (AC), and mesaconitine (MA) in baseline separation. The optimal separation of these Aconitum alkaloids was achieved in a fused-silica capillary column (50 cm x 25 microm id) with 30 mM phosphate solution (pH 8.40) as running buffer at 12 kV applied voltage. The three alkaloids can be determined within 10 min by a single run. The calibration curves showed a linear range from 2.0 x 10(-7) to 2.0 x 10(-5) M for HA, 3.4 x 10(-7) to 1.7 x 10(-5) M for AC, and 3.8 x 10(-7) to 1.9 x 10(-5) M for MA. The RSDs for all analytes were below 3.01%. Good linear relationships were found with correlation coefficients for all analytes exceeding 0.993. The detection limits were 2.0 x 10(-8) M for HA, 1.7 x 10(-7) M for AC, and 1.9 x 10(-7) M for MA under optimal conditions. This method was successfully applied to determine the three alkaloids in Aconitum plants.

HPLC-UV method for nicotine, strychnine, and aconitine in dairy products

The toxic nitrogen alkaloids nicotine, strychnine, and aconitine were quantitated in whole milk, skim milk, and cream using solid-phase extraction cleanup and HPLC-UV with dual wavelength detection. Samples were extracted in McIlvaine's buffer with EDTA and then partitioned with aqueous acetonitrile and hexane. The aqueous phase was concentrated and passed through an OASIS HLB column. The column was eluted with methylene chloride/ammonium hydroxide, 1 mL/1 microL, v/v. The eluent was acidified with hydrochloric acid and evaporated. The sample was diluted for HPLC with acetonitrile/phosphate buffer pH 7.4. Chromatography was performed on an Xterra RP-18 column using a gradient of acetonitrile and ammonium bicarbonate buffer at pH 9.8. Nicotine and strychnine were monitored at 260 nm; aconitine was monitored at 232 nm. Calibration curves were generated from external standards in the range 0.2-10 microg/mL using 1/x weighting. Mean recoveries in whole milk spiked between 0.1 and 10 ppm were the following: nicotine 89.2%, strychnine 75.7%, and aconitine 85.1%. Mean recoveries in skim milk spiked between 0.1 and 10 ppm were the following: nicotine 72.1%, strychnine 78.2%, and aconitine 82.9%. Mean recoveries in cream spiked between 0.2 and 20 ppm were the following: nicotine 87.9%, strychnine 76.9%, and aconitine 82.0%. Relative standard deviations of recovery were less than 20% in each case.

Analysis of strychnos alkaloids using electrospray ionization Fourier transform ion cyclotron resonance multi-stage tandem mass spectrometry

The fragmentations of four strychnos alkaloids have been investigated by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS) in the positive ion mode. Experiments using multi-stage tandem mass spectrometry (ESI-FT-ICR-MSn) allowed us to obtain precise elemental compositions of product ions at high mass resolution. The experimental data demonstrated that the nitrogen bridge and the coordinated oxygen atom on the nitrogen bridge in the alkaloid compounds were the active sites in the MS2 fragmentations. The loss of CH3 or the OCH3 group in those alkaloids, which have an OCH3 substituent, was the dominant fragmentation mode in the MS3 fragmentations. Logical fragmentation schemes for strychnos alkaloids have been proposed and these should be useful for the identification of these compounds.

Differentiation of three pairs of aconite alkaloid isomers from Aconitum nagarum var. lasiandrum by electrospray ionization tandem mass spectrometry

Three pairs of isomers of aconite alkaloids from Aconitum nagarum var. lasiandrum have been investigated by electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (MS/MS) employing ion-trap and quadrupole time-of-flight mass spectrometers in positive mode. Based on the differences of their fragmentation pathways and special fragment ions, three pairs of isomers of aconite alkaloids were differentiated. In addition, fragmentation laws of some veatchines and the discrepancy of fragmentation mechanisms between veatchine-type and aconitine-type alkaloid were also concluded. In the case of veatchines, a radical would be formed by homolysis of C18--C4 or C18--H bonds, followed by elimination of a series of C(2)H(2) and C(2)H(4). Moreover, the retro-Diels-Alder (RDA) reaction occurred in the E-ring and double-electron transfer triggered by the positive charge on C1 led to the formation of diagnostic ions at m/z 216. With regard to aconitine-type alkaloids, the N-substituent is not eliminated easily. Although there is no carbonyl group on some aconitine-type alkaloids, with hydroxyl and methoxyl on C15 and C16 respectively, CO was readily eliminated through tautomerization.

Quantification of Aconitum alkaloids in aconite roots by a modified RP-HPLC method

The three Aconitum alkaloids, aconitine (1), mesaconitine (2) and hypaconitine (3), are pharmacologically active but also highly toxic. A standardised method is needed for assessing the levels of these alkaloids in aconite roots in order to ensure the safe use of these plant materials as medicinal herbs. By optimising extraction, separation and measurement conditions, a reliable, reproducible and accurate method for the quantitative determination of all three Aconitum alkaloids in unprocessed and processed aconite roots has been developed. This method should be appropriate for use in the quality control of Aconitum products. The three Aconitum alkaloids were separated by a modified HPLC method employing a C18 column gradient eluted with acetonitrile and ammonium bicarbonate buffer. Quantification of Aconitum alkaloids, detected at 240 nm, in different batches of samples showed that the content of 1, 2 and 3 varied significantly. In general, the alkaloid content of unprocessed roots was higher than that of processed roots. These variations were considered to be the result of differences in species, processing methods and places of origin of the samples.

Simultaneous determination of six Aconitum alkaloids in proprietary Chinese medicines by high-performance liquid chromatography

By optimizing the extraction, separation and analytical conditions, a reliable and accurate high-performance liquid chromatography (HPLC) method coupled with photodiode array detector (DAD) was developed for simultaneous quantitative determination of six Aconitum alkaloids, i.e., aconitine, mesaconitine, hypaconitine, benzoylaconine, benzoylmesaconine and benzoylhypaconine, in Chinese medicinal herbs, aconite roots, and 12 proprietary Chinese medicines containing processed aconite roots. The separation of these Aconitum alkaloids was achieved on an ODS column with gradient elution using solvents of acetonitrile and ammonium bicarbonate buffer (pH 10.0+/-0.2). Intra-assay and inter-assay precision of the analytes were less than 2.97%, and the average recovery rates obtained were in the range of 90-103% for all with RSDs below 3.28%. Good linear relationships were showed with correlation coefficients for the analytes exceeded 0.999. Quantitative analysis of the six Aconitum alkaloids in the unprocessed and processed aconite roots and in twelve proprietary Chinese medicines containing processed aconite roots showed that the contents of the alkaloids varied significantly. This method and quantitation results can provide a scientific and technical platform to the products manufacturers for setting up a quality control standard as well as to the public for quality and safety assurance of the proprietary Chinese medicines and other herbal preparations containing aconite roots.

Determination of bulleyaconitine A in human plasma by liquid chromatography-electrospray ionization tandem mass spectrometry

A sensitive and specific high-performance liquid chromatography (HPLC)-electrospray ionization tandem mass spectrometry (MS-MS) was developed for the determination of bulleyaconitine A (BLA) in human plasma. BLA and internal standard (I.S.) ketoconazole were extracted from the plasma by a liquid-liquid extraction. The supernatant was evaporated to complete dryness and reconstituted with acetonitrile containing 0.1% acetic acid before injecting into an ODS MS column. The gradient mobile phase was composed of a mixture of acetonitrile (containing 0.1% acetic acid, v/v) and 0.1% acetic acid aqueous solution eluted at 0.3 ml/min. BLA and I.S. were determined by multiple reaction monitoring using precursor-->product ion combinations at m/z 644.6-->584.3 and 531.2-->81.6, respectively. Linearity was established for the concentration range of 0.12-6 ng/ml. The recoveries of BLA ranged from 96.93 to 113.9% and the R.S.D. was within 20%. The method is rapid and applicable to the pharmacokinetic studies of BLA in human.

Analysis of Chinese medicine preparations by capillary electrophoresis–mass spectrometry

In Chinese medicines, herbs are usually prepared before use by patients. Since the preparation procedures convert the original component into one or more products, study of the procedures is usually complex and involves several compounds. On-line coupling of capillary electrophoresis (CE) to mass spectrometry (MS) allows both the efficient separation of CE and the specific and sensitive detection of MS to be achieved. In this study, CE-MS was applied to the determination of alkaloids in Maqianzi (the seed of Strychnos pierrian) and Wutou (aconite root, Radix aconiti praeparata) during the preparation procedure. With optimal CE-MS conditions, alkaloids in both prepared and unprepared Maqianzi were determined successfully in the total ion current (TIC) mode. However, single ion monitoring (SIM) had to be applied for the separation of aconitum alkaloids and their hydrolysis products. Quantification data indicated that MS detection under SIM mode is more sensitive than UV detection. Based on the CE-MS method developed, the hydrolysis of aconitum alkaloids in water and methanol was also studied.

Characterization of aconitine-type alkaloids in the flowers of Aconitum kusnezoffii by electrospray ionization tandem mass spectrometry

The fragmentation mechanism of aconitine-type alkaloids in the flowers of Aconitum kusnezoffii (FAK) was investigated using electrospray ionization tandem mass spectrometry (ESI-MS(n)) firstly. The analysis of the collision-induced dissociation (CID) spectra of three purified aconitine standards and six previously reported aconitines indicated that the fragmentation of the protonated aconitines at low-energy CID follows a similar pathway. The elimination of a C(8)-substituent such as an acetic acid or a fatty acid is the dominant fragmentation mode in MS2. Successive losses of CH(3)COOH, CH(3)OH, H(2)O, BzOH, and CO are the main fragmentation pathways of aconitine-type alkaloids in MS(3) spectra. Based on these features, a rapid method for the direct detection and characterization of alkaloids from an ethanolic extract of FAK is described. All the known aconitum alkaloids are detected and a series of lipo-aconitines has been found for the first time in this plant.

A new enzyme immunoassay for aconitine and its application to quantitative determination of aconitine levels in plasma

A reliable enzyme immunoassay (EIA) method was developed for quantitative determination of aconitine with high sensitivity and specificity. The bovine serum albumin (BSA)- and beta-galactosidase (beta-Gal) conjugates as immunogens and enzyme-labeled antigens were prepared by coupling of their proteins with succinic acid (short chain length; n=2, where n represents the number of methylene units) and hexadecanedioic acid (long chain length; n=14) hemiesters of benzoylaconine through the respective N-hydroxysuccinimide esters as intermediates. Two types of the BSA-conjugates with short and long chains were repeatedly injected into rabbits to obtain anti-aconitine antisera (As1 and As2, respectively). All combinations of beta-Gal-labeled antigens LAg1 (n=2) and LAg2 (n=14) with antisera As1 (n=2) and As2 (n=14) showed high sensitivity to aconitine in a range of 0.1-1.0 ng. Although the combination of LAg2 (n=14) with antiserum As1 (n=2) showed high specificity to aconitine, the combination of LAg2 (n=14) and As2 (n=14) was highly specific to both aconitine and mesaconitine. When aconitine was intravenously administered to rats, the aconitine concentration in their plasma remarkably decreased within the first 60 min, and then gradually declined, suggesting a two-compartment pharmacokinetic model in (V(c) 0.41+/-0.09 l/kg, V(dss) 1.7+/-0.4 l/kg, CL(tot) 10+/-2 ml/min x kg, AUC(0-4800) 2055+/-294.3 ng x min/ml). Following oral administration of aconitine to rats at two doses of 0.1 and 1.0 mg/kg b.w., the maximum plasma concentrations (C(max)) were 0.73+/-0.08 and 3.3+/-0.6 ng/ml at times of 45+/-9 and 150+/-52 min, respectively, and the AUC(0-1440) values were 130+/-4 and 1600+/-270 ng x min/ml. The bioavailability (F) of aconitine was determined to be 0.013, where only 1.3% of the aconitine administered orally was absorbed into the body fluid.

Exact mass measurement of product ions for the structural confirmation and identification of unknown compounds using a quadrupole time-of-flight spectrometer: a simplified approach using combined tandem mass spectrometric functions

This article describes a simple method to perform lock mass corrected accurate mass measurements in tandem mass spectrometry (MS/MS) with a quadrupole time-of-flight (Q-TOF) mass spectrometer. The experimental approach consists of using the protonated molecule of a known compound, which is measured in a MS/MS function using low collision energy (no fragmentation), as mass calibrator. The unknown compound is acquired in MS/MS mode albeit using high collision energy. After the acquisition, the two MS/MS spectra of unknown and mass calibrator are combined, and the fragments of the unknown are lock mass corrected by using the protonated molecule of the mass calibrator. To prove this concept, 10 compounds were analyzed using this approach, the fragments interpreted and, where possible, related to structural data available in the literature. All the unequivocally assigned fragments were accurately mass measured with mass errors within appropriate limits, i.e. for m/z values <200 with a mass tolerance of 3 mDa while for m/z > 200 the mass tolerance is expressed as 10 ppm.

Exploring the ester-exchange reactions of diester-diterpenoid alkaloids in the aconite decoction process by electrospray ionization tandem mass spectrometry

The chemical components in the decoctions of Chinese herbal medicines are not always the same as those in the crude herbs because of the insolubility or instability of some compounds. In this work electrospray ionization tandem mass spectrometry was used to explore the ester-exchange reactions for aconitine-type diester-diterpenoid alkaloids occurring during the process of decocting aconite root. The aconitines were screened in a diverse range of samples, including crude aconite, decoction of crude aconite, residues from decoction of crude aconite, prepared aconite, decoction of prepared aconite, decoction of prepared aconite with added palmitic acid, and decoction of a mixture of mesaconitine and hypaconitine standards with liquorice root. It was found that diester-diterpenoid aconitines were converted into lipo-alkaloids as well as monoester alkaloids by the decoction of aconite.

Determination of five toxic alkaloids in two common herbal medicines with capillary electrophoresis

A method was developed for the determination of five highly toxic alkaloids in two commonly used herbal medicines by capillary electrophoresis, which had not been applied to the determination of Aconitum alkaloids before. The buffer contained 40 mM ammonium acetate and 0.1% acetic acid in 80% methanol. Five alkaloids can be determined in 15 min by a single run. The calibration curves showed a linear range from 2 to 200 mg/l for these alkaloids with correlation coefficients (R2) between 0.9988 and 0.9999. Detection limits (SIN = 3) varied from 0.85 to 1.90 mg/l. Recoveries ranged from 95 to 108.8%. The method can provide an effective tool for the strict control of these fetal herbal medicine components.

A case of fatal poisoning with the aconite plant: quantitative analysis in biological fluid

In recent years recorded cases of plant poisoning have become rare, this may in part be due to the possibility of plant ingestion not being indicated at the beginning of an investigation. Aconitum napellus (aconite, Wolfsbane, Monkshood) is one of the most poisonous plants in the UK. It contains various potent alkaloids such as aconitine, isoaconitine, lycaconitine and napelline. Ingestion of Aconitum plant extracts can result in severe, potentially fatal toxic effects. This paper describes the analytical findings in a recent death in the UK. resulting from deliberate ingestion of Aconitum napellus extract. The concentrations of aconitine measured by HPLC-DAD in the post mortem femoral blood and urine were 10.8 micrograms/L and 264 micrograms/L, respectively. The aconitine concentration in the ante mortem urine was 334 micrograms/L and was estimated to be 6 micrograms/L in the ante mortem serum. Hence, accidental, suicidal or homicidal poisoning due to the ingestion of plant material remains a possibility and should be borne in mind when investigating sudden or unexplained death.

Liquid chromatography-mass spectrometry in forensic toxicology

Liquid chromatography-mass spectrometry has evolved from a topic of mainly research interest into a routinely usable tool in various application fields. With the advent of new ionization approaches, especially atmospheric pressure, the technique has established itself firmly in many areas of research. Although many applications prove that LC-MS is a valuable complementary analytical tool to GC-MS and has the potential to largely extend the application field of mass spectrometry to hitherto "MS-phobic" molecules, we must recognize that the use of LC-MS in forensic toxicology remains relatively rare. This rarity is all the more surprising because forensic toxicologists find themselves often confronted with the daunting task of actually searching for evidence materials on a scientific basis without any indication of the direction in which to search. Through the years, mass spectrometry, mainly in the GC-MS form, has gained a leading role in the way such quandaries are tackled. The advent of robust, bioanalytically compatible combinations of liquid chromatographic separation with mass spectrometric detection really opens new perspectives in terms of mass spectrometric identification of difficult molecules (e.g., polar metabolites) or biopolymers with toxicological relevance, high throughput, and versatility. Of course, analytical toxicologists are generally mass spectrometry users rather than mass spectrometrists, and this difference certainly explains the slow start of LC-MS in this field. Nevertheless, some valuable applications have been published, and it seems that the introduction of the more universal atmospheric pressure ionization interfaces really has boosted interests. This review presents an overview of what has been realized in forensic toxicological LC-MS. After a short introduction into LC-MS interfacing operational characteristics (or limitations), it covers applications that range from illicit drugs to often abused prescription medicines and some natural poisons. As such, we hope it can act as an appetizer to those involved in forensic toxicology but still hesitating to invest in LC-MS.

Poisoning by plant material: review of human cases and analytical determination of main toxins by high-performance liquid chromatography-(tandem) mass spectrometry

The authors have reviewed the main toxic plants responsible for human deaths throughout the world. Forty plants (genera or species) were listed in order to establish an inventory of the active molecules that could be identified, the already published analytical methods and the reported human fatal cases. In a second step, the authors have developed a general method for the detection of various toxins in whole blood by high-performance liquid chromatography coupled to mass spectrometry or tandem mass spectrometry. Sample preparation was realized by liquid-liquid extraction at pH 9.5 for oleandrine, taxol and the alkaloids. These latter compounds were divided into two groups following their chemical properties and could be subsequently purified by acid/base clean up. Cyanogenic compounds and atractyloside were isolated by precipitation of the protein content with acetone and purified for atractyloside by washing with chloroform. Separation of the drugs occurred under reversed-phase conditions on a C18 analytical column 150x2 mm I.D. (5 microm particle size) using two different mobile phases. The first one, formiate buffer 2 mM acidified at pH 3.0, was used for the separation of atractyloside, oleandrine, taxol, the cyanogenic molecules and some alkaloids. The second mobile phase, formiate buffer 10 mM made basic at pH 8.2 was used for the majority of other alkaloids. A gradient elution mode was chosen using acetonitrile or acetonitrile-methanol (50:50, v/v) as the eluting solvent. Detection under positive ionization mode was the mode of choice for all compounds except for atractyloside (negative ions) and for taxol (mixed mode available). Application to real forensic cases has been demonstrated.

Determination of Aconitum alkaloids in blood and urine samples. II. Capillary liquid chromatographic-frit fast atom bombardment mass spectrometric analysis

Determination of fourteen alkaloids, toxic Aconitum alkaloids, aconitine, mesaconitine, jesaconitine, hypaconitine and deoxyaconitine, and their hydrolysis products, benzoylaconines and aconines, have been established using capillary liquid chromatography (LC) fast atom bombardment mass spectrometry (FAB-MS) with a frit interface. Protonated molecular ions were observed as base peaks in the FAB-MS for these fourteen alkaloids. All the alkaloids were simultaneously quantified with linear gradient LC elution by solvent mixture of acetonitrile and 0.3% trifluoroacetic acid using selected ion monitoring of the protonated molecular ions. The calibration curves of these alkaloids were linear in injection amounts ranging from 5 to 500 pg, and their detection limits were 1 pg per injection (S/N=3). Solid-phase extraction using Sep-Pak Plus PS-1 was also investigated to clean-up and concentrate alkaloids in blood and urine samples, and showed satisfactory recoveries. This capillary LC-frit-FAB-MS method enables determination of low levels of Aconitum alkaloids in blood and urine samples, coupled with solid-phase extraction.