[Analysis on the metabolites of mesaconitine in the rat urine by liquid chromatography and electrospray ionization mass spectrometry]

The mesaconitine and its major metabolites in the rat urine were identified by liquid chromatography and electrospray ionization tandem mass spectrometry. The rat urine was collected for consecutive 24 hours from the rat following intragastric infusion of mesaconitine, subsequently which were enriched and purified using solid phase extraction. The metabolites of mesaconitine in the rat urine were analyzed by the liquid chromatography and electrospray ionization tandem mass spectrometry. It is shown that the parent drug mesaconitine and its metabolites were found in the rat urine, such as hypo-mesaconitine glucuronic acid conjugate, 10-hydroxy-mesaconitine, 1-O-demethyl mesaconitine, deoxy-mesaconitine and hypo-mesaconitine. Among the five of metabolites, the hypo-mesaconitine glucuronic acid conjugate (m/z 766) was first discovered as the aconitine in rats phase II metabolites, which revealed a new way of mesaconitine metabolism in rats.

[Distribution of aconitum alkaloids in the corpse died of acute aconite intoxication]

OBJECTIVE

To investigate the distribution of aconite alkaloids in biological fluids and tissues in the corpse died of acute aconite intoxication and to provide information for sample selection and result evaluation in forensic identification.

METHODS

The content of aconite alkaloids in biological fluids and tissues were determined by liquid chromatography-tandem mass spectrometry.

RESULTS

The content of aconite displayed in decending order of urine, bile, gastric content, heart blood, pancreas, heart, intestine, liver, kidney, stomach, lung, gallbladder and spleen, with no aconite detected in the brain.

CONCLUSION

It was indicated that urine, bile and blood are the best specimens for the determination of aconite in body of the acute aconite intoxication.

Five cases of aconite poisoning: toxicokinetics of aconitines

Aconite poisoning was examined in five patients (four males and one female) aged 49 to 78 years old. The electrocardiogram findings were as follows: ventricular tachycardia and ventricular fibrillation in case 1, premature ventricular contraction and accelerated idioventricular rhythm in case 2, AIVR in case 3, and nonsustained ventricular tachycardia in cases 4 and 5. The patient in case 1 was given percutaneous cardiopulmonary support because of unstable hemodynamics, whereas the other patients were treated with fluid replacement and antiarrhythmic agents. The main aconitine alkaloid in each patient had a half-life that ranged from 5.8 to 15.4 h over the five cases, and other detected alkaloids had half-lives similar to the half-life of the main alkaloid in each case. The half-life of the main alkaloid in case 1 was about twice as long as the half-lives in the other cases, and high values for the area under the blood concentration-time curve and the mean residence time were only observed in case 1. These results suggest that alkaloid toxicokinetics parameters may reflect the severity of toxic symptoms in aconite poisoning.

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.

Hidden Aconite Poisoning: Identification of Yunaconitine and Related Aconitum Alkaloids in Urine by Liquid Chromatography-Tandem Mass Spectrometry

Poisoning from aconite occurs worldwide as a result of misuse of the potent plant. Laboratory investigation into suspected intoxication cases is challenging because the content of toxic aconitum alkaloids varies depending on the plant source, market processing, dosing protocol, hydrolytic degradation, and metabolic transformation. Using a triple-quadrupole tandem mass spectrometer, a group screening method was developed based on the mass-fragmentographic scheme of common aconitum alkaloids. The precursor-ion scans of m/z 105 and 135 permitted selective profiling of 14-O-benzoyl-norditerpenoids and the 14-O-anisoyl-norditerpenoids, respectively. Gradient reversed-phase liquid chromatography minimized coelution of isobaric compounds. The screening protocol was applied to a clinical investigation of suspected herbal poisoning. In total, 15 urine samples were thus screened positive for aconitum alkaloid over 5 years. The diagnoses of aconite poisoning in 11 patients were firmly established based on the known prescription history and the positive urine finding. In four patients, without aconitum herbs being listed in the herbal prescriptions, contamination of the herbal remedies by aconite was suspected to be the hidden cause of their acute poisoning. Yunaconitne, a highly toxic aconitum alkaloid, was thus identified in human urine for the first time. The group screening method of aconitum alkaloids in urine is an important diagnostic aid for acute poisoning by aconites of an unclear origin.

Quantitative determination of Aconitum alkaloids in blood and urine samples by high-performance liquid chromatography

An HPLC method has been developed for the simultaneous determination of the toxic Aconitum alkaloids, aconitine, mesaconitine and hypaconitine in blood and urine samples. The samples were initially subjected to solid phase extraction using Oasis MCX cartridges, and the alkaloids were separated on an XTerra RP18 column, gradient-eluted with acetonitrile: ammonium hydrogen carbonate buffer. Calibration curves were linear in the range 2.75-550 ng for aconitine and hypaconitine, and 3-600 ng for mesaconitine: the limit of detection was 0.1 ng (signal-to-noise ratio of 3) for each alkaloid. The described analysis proved to be sensitive, rapid and economical, and will be applied in the identification and determination of these alkaloids in forensic and therapeutic drug monitoring.

[Study on metabolites on aconitine in rabbit urine]

AIM

To identify the main metabolites of aconitine in the urine of rabbits.

METHODS

After oral administration of aconitine (5 mg.kg-1), the urine of male rabbits was collected and extracted by solid phase extraction and analyzed by liquid chromatography-ion trap mass spectrometry.

RESULTS

Aconitine and 4 metabolites were found in the rabbit urine. Their protonated molecular ions at m/z 632, m/z 604, m/z 590, m/z 500 and multistage fragment ions with neutral loss of 60 u, 32 u, 28 u and 18 u were monitored. Their relative concentration were M1 > Aconitine > M4 > M2 > M3.

CONCLUSION

The metabolites M1-M4 were deduced as 16-O-demethylaconitine, benzoylaconine, 16-O-demethylbenzoylaconine and aconine, respectively.

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.

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.

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

Determination of four toxic Aconitum alkaloids, aconitine, mesaconitine, hypaconitine and jesaconitine, in blood and urine samples has been established using high-performance liquid chromatography (HPLC) combined with ultraviolet absorbance detection, solid-phase extraction and mass spectrometry (MS). These alkaloids were hydrolyzed rapidly in alkaline solution (half lives (t1/2)<one day), were stable in solutions of acetonitrile, tetrahydrofuran and diluted hydrochloric acid (t1/2>five months) and were unstable in solutions of methanol and ethanol (t1/2<one month). These alkaloids were separated on an octadecylsilica column with isocratic elution using a solvent mixture of tetrahydrofuran and 0.2% trifluoroacetic acid (14:86, v/v), which was found to be the optimal solvent of the elution systems examined. Calibration curves with UV detection were linear on injection of amounts ranging from 2.5 to 500 ng, and the limit of detection was 1 ng (S/N=3). These four alkaloids in aqueous solution were recovered almost totally by solid-phase extraction using the styrene polymer resin, Sep-Pak Plus PS-1, and were eluted using a mixture of acetonitrile and hydrochloric acid. These Aconitum alkaloids were confirmed by HPLC coupled with fast atom bombardment MS, giving their protonated molecular ions as base peaks. These alkaloids were detected by HPLC with UV detection from blood samples spiked with more than 50 ng ml(-1) of alkaloids, but were not detectable from urine samples spiked with 5 microg ml(-1) of alkaloids because of severe sample interference.

A case of aconitine poisoning with analysis of aconitine alkaloids by GC/SIM

Described here is a fatal case of accidental aconitine poisoning following the ingestion of aconite, Torikabuto, mistaken for an edible grass, Momijigasa. A 61-year-old man developed symptoms of nausea, diarrhea, and discomfort of the body about 2 h after the ingestion and was taken to an emergency room. Resuscitation and antiarrhythmic drugs were ineffective, and ventricular tachycardia and fibrillation developed and lasted for 6 h. He was transferred to a coronary care unit and complete sinus rhythm was obtained on an electrocardiogram 30 h after his admission. The patient fell into a coma and died of brain edema diagnosed by CT on the 6th day. Consent for autopsy was denied by the family but was given for gas chromatography/selected ion monitoring (GC/SIM) to analyze the toxicity of aconitine alkaloids in the blood and the urine. Only a faint amount of jesaconitine was detected, while aconitine, mesaconitine and hypaconitine were not detectable in the blood 24 h after ingestion. On the other hand, aconitine and its related alkaloids such as mesaconitine, jesaconitine, and hypaconitine were clearly detected in the urine.

Separation and characterization of the metabolic products of lappaconitine in rat urine by high-performance liquid chromatography

The separation and characterization of the metabolic products of lappaconitine in rat urine by high-performance liquid chromatography with electrochemical and ultraviolet detection are described. Urine samples from rats intravenously administered lappaconitine hydrobromide were extracted with chloroform and then purified on a Sep-Pak C18 cartridge. The subsequent resolution into individual compounds was achieved by high-performance liquid chromatography. Identification of these compounds was based on comparisons of the chromatographic behaviour and the detector response with those of authentic samples. Changes in the ratio of lappaconitine to its metabolites in rat urine with time after dosing led to a proposal for one of the probable metabolic pathways of lappaconitine in the rat.

Studies on the metabolism of lappaconitine in humans. Identification of the metabolites of lappaconitine in human urine by high performance liquid chromatography

The metabolites of lappaconitine in the urine of humans having been previously administered intramuscularly with lappaconitine hydrobromide were studied using high performance liquid chromatography with electrochemical and ultraviolet detection. The urine was extracted by means of liquid- and solid-phase extractions. Each of the metabolites of lappaconitine was purified by high performance liquid chromatography on a reversed phase column and identified on the basis of the chromatographic behaviour and the detector response. It was proved that lappaconitine, N-deacetyl-16-O-demethyllappaconitine and N-deacetyllappaconitine were excreted in urine from humans receiving lappaconitine.

Colorimetric determination of aconitine in galenicals and in biological samples

A sensitive method is presented for determining aconitine. Aconitine is complexed with Co2+, the aconitine-cobalt complex is extracted with chloroform, and the absorbance is measured at 320 nm. The sensitivity of the method ranged between 0.06 and 3 mg/25 ml, and the color was stable for 6 hr. The method was successfully applied for the quantitative determination of aconitine in animal tissues.