Quantitative determination of taxine B in body fluids by LC–MS–MS

Natural Taxanes: From Plant Composition to Human Pharmacology and Toxicity

Biologically active taxanes, present in small- to medium-sized evergreen conifers of various Taxus species, are widely used for their antioxidant, antimicrobial and anti-inflammatory effects, but mostly for their antitumour effects used in the treatment of solid tumours of the breast, ovary, lung, bladder, prostate, oesophagus and melanoma. More of the substances found in Taxus plant extracts have medical potential. Therefore, at the beginning of this review, we describe the methods of isolation, identification and determination of taxanes in different plant parts. One of the most important taxanes is paclitaxel, for which we summarize the pharmacokinetic parameters of its different formulations. We also describe toxicological risks during clinical therapy such as hypersensitivity, neurotoxicity, gastrointestinal, cardiovascular, haematological, skin and renal toxicity and toxicity to the respiratory system. Since the effect of the drug-form PTX is enhanced by various Taxus spp. extracts, we summarize published clinical intoxications and all fatal poisonings for the Taxus baccata plant. This showed that, despite their significant use in anticancer treatment, attention should also be focused on the risk of fatal intoxication due to ingestion of extracts from these plants, which are commonly found in our surroundings.

Fatal ingestion of Taxus baccata: English yew

Poisoning from consumption of foraged alternative medicine products is an uncommon yet recognized occurrence. Here, presented is the case of a 40-year-old woman who was witnessed to collapse with labored breathing and subsequently died despite emergency medical personnel attendance and resuscitation efforts. Autopsy revealed the presence of plant matter that was visually identified as leaves from Taxus baccata - the English Yew. Isolation of alkaloids from the plant material and subsequent identification of the same alkaloids in the decedent's blood by liquid chromatography-tandem mass spectrometry indicated a toxicological cause of death. This case illustrates a collaborative team approach among subject matter experts to unexpectedly discover and then confirm the sudden death of this woman from T. baccata toxicity.

Taxus ingredients in the red arils of Taxus baccata L. determined by HPLC-MS/MS

INTRODUCTION

Taxus baccata L. is an evergreen conifer whose plant parts are cardiotoxic. Only the red arils of the berries are described as non-toxic and taxane-free.

OBJECTIVE

Extraction and HPLC-MS/MS methods were developed for the investigation of the Taxus compounds 3,5-dimethoxyphenol, 10-deacetylbaccatin III, baccatin III, cephalomannine, taxol A and taxinine M in the red arils of the yew berries.

METHODOLOGY

A liquid-liquid extraction method for the red arils of the fruits from three yews were developed. An accurate (ESI+) HPLC-MS/MS method was performed for the simultaneous detection and determination of the target compounds in multiple reaction monitoring (MRM) mode.

RESULTS

All Taxus agents obtained were detected in the red arils. Highest concentrations were determined for baccatin III and 10-deacetylbaccatin III.

CONCLUSION

The developed quantitative method is reliable and selective and was successfully applied for quantification of selected Taxus ingredients in red arils of Taxus baccata. It was disproved that the red arils of the berries do not contain the selected Taxus compounds.

Yew (Taxus) intoxication in free-ranging cervids

Wild ruminants, including deer species (cervids) have incorrectly been regarded as refractory to yew (Taxus) intoxication. This assumption has been based upon anecdotal observations of individual deer browsing on yew over time without apparent adverse effect. A single case of yew intoxication was reported in a free-ranging Norwegian moose (Alces alces) in 2008. The current report describes five additional cases of yew toxicosis in moose, seven in roe deer (Capreolus capreolus) and two in reindeer (Rangifer tarandus tarandus), all in Norway. The animals were found dead during the winter, close to or within gardens containing yew plants showing signs of browsing. Gross findings included lung congestion and edema, thoracic and pericardial effusion, bilateral heart dilatation, epi- and endocardial hemorrhage, and enlarged (congested) spleen. Yew plant remnants were detected in the rumen of all animals with the exception of a single moose. Histology revealed multifocal acute myocardial degeneration and necrosis with hemorrhage in roe deer, but not in the two other species. A qualitative high performance liquid chromatography-ion trap mass spectrometry analysis was used to tentatively identify five major Taxus alkaloids (taxines) in crude yew extracts and in heart and liver samples from the moose cases. All five major taxines were detected with good signal/noise ratio in tissue samples from the four moose with visible ruminal yew content, whereas lower levels of taxines were detected in the moose without visible ruminal yew content. Possible differences in interspecies tolerance to taxines and role of individual protective adaptation are discussed.

Laser Desorption/Ionisation Mass Spectrometry Imaging of European Yew (Taxus baccata) on Gold Nanoparticle-enhanced Target

INTRODUCTION

European yew (Taxus baccata) is a plant known to man for centuries as it produces many interesting and important metabolites. These chemical compounds were repeatedly analysed by various analytical techniques, but none of the methods used so far allowed the localisation of the chemical compounds within the tissue and also correlation between plant morphology and its biochemistry.

OBJECTIVE

Visualisation of the spatial distribution of yew metabolites with nanoparticle-based mass spectrometry imaging.

METHODOLOGY

Compounds occurring on cross-section of a one-year yew sprig has been transferred to gold nanoparticle-enhanced target (AuNPET) by imprinting. The imprint was then subjected to mass spectrometry imaging analysis.

RESULTS

Nanoparticle-enhanced mass spectrometry imaging made it possible to study the distribution of selected compounds in the European yew tissue, including taxanes - terpene alkaloids characteristic for the Taxus genus. Results prove that aspartate, taxinine M, baccatin IV and taxine B are located mainly in the cortex. Taxuspine W was located in the vascular tissue. Maleate was found to be located mainly in the phloem tissue. In contrast, the proton adduct of chlorophyll b was found in the external layer of twigs.

CONCLUSION

The results presented a high correlation between the location of compounds and the morphology of the plant, thus giving the opportunity to see the selected details of chemical structure of the analysed tissue for the first time. Copyright © 2017 John Wiley & Sons, Ltd.

A suicide attempt by intoxication with Taxus baccata leaves and ultra-fast liquid chromatography-electrospray ionization-tandem mass spectrometry, analysis of patient serum and different plant samples: case report

BACKGROUND

Taxus (yew) is one of the most frequently reported plants causing potentially fatal outcome when taken incidentally or for suicidal reasons. A fast and reliable method of detection of poisonous compounds or their metabolites is critical in life-saving procedures in cases of yew ingestion. Previously, several chromatographic analytical procedures have been described usually taking longer than one hour of total analysis time.

CASE PRESENTATION

In this report we describe a suicide case study and an ad hoc developed fast method of detection and quantitation of 3,5-dimethoxyphenol - the main taxane metabolite in the blood plasma from the patient as well as the determination of major taxine components in the plant material (Taxus baccata). At present, there is no reasonable alternative for mass spectrometry that could match its high sensitivity and accuracy, and Multiple Reaction Monitoring could be adequate and useful mass spectrometry technique in analyzing and identification of plants material compounds that cause severe poisoning in humans. In the reported case, intensive cardiac care together with the astuteness of the treating physicians not only saved the patient's life, but also allowed for his complete recovery and return to work.

CONCLUSIONS

The development of ultra fast liquid chromatography tandem mass spectrometry UFLC-MS/MS method provides a fast means to confirm yew alkaloids and their metabolite in various material. The applied analytical procedure allows early detection of main metabolite in patient material as well as comparing to those extracted from the plant. In our study, the taxanes remained undetected, probably due to the time elapsing from the patient admittance and collection of plasma. In cases like those reported in this study, retaining the gastric material should be obligatory to confirm the ingestion of yew. The possibility of using this approach in detection of native taxine compounds in human plasma remains to be verified.

Generic detection of basic taxoids in wood of European Yew (Taxus baccata) by liquid chromatography-ion trap mass spectrometry

The occurrence of the cardiotoxin taxine (comprising taxine B and several other basic taxoids) in leaves of Taxus baccata L. (European yew) is well known and has led to public concerns about the safety of eating or drinking from utensils crafted from the wood of this poisonous species. The occurrence of basic taxoids in the heartwood of T. baccata had not been examined in detail, although the bark is known to contain 2'β-deacetoxyaustrospicatine. Initial examination of heartwood extracts for 2'β-deacetoxyaustrospicatine by liquid chromatography-mass spectrometry (LC-MS) revealed the presence of this basic taxoid at about 0.0007% dry weight, using a standard isolated from bark. Analyses for taxine B, however, proved negative at the extract concentration analysed. Observing other basic taxoids within the heartwood extracts was facilitated by developing generic LC-MS methods that utilised a fragment arising from the N-containing acyl group of basic taxoids as a reporter ion. Of the various MS strategies available on a hybrid ion trap-orbitrap instrument that allowed observation of this reporter ion, combining all-ion collisions with high resolution ion filtering by the orbitrap was most effective, both in terms of the number of basic taxoids detected and sensitivity. Numerous basic taxoids, in addition to 2'β-deacetoxyaustrospicatine, were revealed by this method in heartwood extracts of T. baccata. Red wine readily extracted the basic taxoids from heartwood while coffee extracted them less efficiently. Contamination with basic taxoids could also be detected in soft cheese that had been spread onto wood. The generic LC-MS method for detecting basic taxoids complements specific methods for detecting taxine B when investigating yew poisoning cases in which the analysis of complex extracts may be required or taxine B has not been detected.

Eight cases of fatal and non-fatal poisoning with Taxus baccata

This paper describes two fatalities, three non-fatal intentional and three accidental oral ingestions of yew (Taxus baccata) leaves. In all cases the post-mortem external examinations showed no signs of violence. Internal examinations revealed small green, needle-like particles on the tongue, in the esophagus and in the stomach. Yew leaves were also identified in the stomach contents, whereas Taxus leaves were cut into small pieces and then ingested in one case. The analytical method used was based on a liquid-liquid-extraction under alkaline conditions followed by LC-MS/MS analysis (QTRAP 5500). Chromatographic separation was achieved by HPLC on a Kinetex C18 2.6u (100×3) mm. The analytical method allows the simultaneous identification and quantification of the commercially available yew alkaloids taxoids (m/z): paclitaxel (854.2→105.0/286.1), 10-deacetyltaxol (10-DAT: 812.2→105.0/286.1), baccatin III (BAC III: 604.0→105.0/327.0), 10-deacetylbaccatin III (10-DAB III: 562.1→105.0/327.0), cephalomannine [taxol B] (562.1→105.0/327.0) and of 3,5-dimethoxyphenol (3,5-DMP: 155.0→111.9/122.9) also encompassing the qualitative analysis of the alkaloidal diterpenoids (Q1→194.0/107.0); reference mass spectra obtained from a yew leaves extract: monoacetyltaxine (MAT: 568.4), taxine B (584.2), monohydroxydiacetyltaxine (MHDAT: 626.4), triacetyltaxine (TAT: 652.4), monohydroxytriacetyltaxine (MHTAT: 668.4). In both fatalities, paclitaxel, 10-DAT and cephalomannine were not identified in urine, cardiac and femoral blood but all taxoids and 3,5-DMP were present in stomach content and excreted into the bile. In urine, highest 3,5-DMP concentration was 7500 μg/L and 23,000 μg/L after enzymatic hydrolysis, respectively. In intentional and accidental poisonings, when electrocardiogram (ECG) examinations revealed ventricular tachycardia and/or prolonged QRS intervals, taxines were identified in plasma/serum, even after the ingestion of a few number of yew leaves, when 3,5-dimethoxyphenol was not even found. According to the data from one near-fatal intentional poisoning, elimination half-life of MAT, TAXIN B, MHDAT and MHTAT in serum was calculated with 11-13 h and taxines were detected up to t=+122 h post-ingestion of approximately two handfuls of yew leaves.

Fatal poisoning with Taxus baccata: quantification of paclitaxel (taxol A), 10-deacetyltaxol, baccatin III, 10-deacetylbaccatin III, cephalomannine (taxol B), and 3,5-dimethoxyphenol in body fluids by liquid chromatography-tandem mass spectrometry

This method development was to confirm the fatal ingestion of toxic yew plant material in postmortem samples (stomach content, urine, femoral blood, cardiac blood, bile, and brain tissue) collected from a 22-year-old man who committed suicide by ingesting yew leaves. The analytical method was based on a liquid-liquid extraction under alkaline conditions followed by LC-MS-MS analysis. Chromatographic separation was achieved by HPLC on a Kinetex C18 2.6u (100 × 3 mm) coupled to a QTRAP 5500 system. The method allows the simultaneous identification and quantification of the yew alkaloids taxoids paclitaxel (taxol A), 10-deacetyltaxol, baccatin III, 10-deacetylbaccatin III, cephalomannine (taxol B), and 3,5-dimethoxyphenol; the alkaloidal diterpenoids monoacetyltaxine, taxine B, monohydroxydiacetyltaxine, triacetyltaxine, and monohydroxytriacetyltaxine were also identified. The initial hypothesis of yew tree (Taxus baccata) poisoning was confirmed. The quantitative evaluation revealed taxoid concentrations ranging from 4.5 to 132 µg/L (stomach content), 1 to 200 µg/L (urine), <0.5 to 12 µg/L (cardiac blood), <0.5 to 7.3 µg/L (femoral blood), and 4.9 to 290 µg/L (bile). In brain tissue, none of these taxoids could be detected (<0.5 µg/L). In urine, after enzymatic hydrolysis, the concentration of 3,5-dimethoxyphenol (3,5-DMP) was 23,000 µg/L. The alkaloidal diterpenoids were found in all postmortem samples. The newly developed LC-MS-MS method enables the identification of alkaloidal and non-alkaloidal diterpenoids and 3,5-dimethoxyphenol in human body fluids and tissues for the confirmation of accidental or intentional poisonings with yew plant material.

Monitoring of aglycons of yew glycosides (3,5-dimethoxyphenol, myrtenol and 1-octen-3-ol) as first indicator of yew presence

The toxicity of yew (Taxus spp) is well known from ancient times and is mainly due to taxins acting as inhibitors of calcium and sodium transport across the cell membrane of cardiac myocytes. The confirmation of yew taxins in body fluids can be carried out by liquid chromatography-tandem mass spectrometry (LC-MS/MS). However, before selecting this precise but expensive technique, an orientation test should be done to ascertain yew presence as toxic agent in the organism. As the 3,5-dimethoxyphenol (3,5-DMP), myrtenol and 1-octen-3-ol appear as glycosidically bound volatile compounds and are very yew specific, the detection of 3,5-DMP and the measurement of 1-octen-3-ol / myrtenol concentration ratio constitute reliable indicators of yew presence in forensic cases. The detection of these compounds is easily performed by gas chromatography-mass spectrometry (GC-MS) (SIM) after an enzymatic hydrolysis (β-glucosidase) allowing the release of volatile compounds from yew glycosides.

Application of direct PCR in a forensic case of yew poisoning

Intoxications with yew (Taxus spp.) pose a challenge to forensic toxicology because a variety of Taxus ingredients have been associated with its toxic effects. To provide preliminary evidence in cases where plant material is available, we introduce a novel direct PCR assay for the detection of DNA traces from Taxus spp. This assay has been successfully applied to a forensic case of suicidal poisoning via ingestion of Taxus leaves. PCR primers were designed to target a sequence located in the internal transcribed spacer 1 (ITS1) of nuclear ribosomal DNA, which is well conserved among species of the genus Taxus and can, therefore, be exploited to discriminate between Taxus and other conifers. Because ITS1 exists as a multicopy sequence within the plant genome, the assay provides enough sensitivity to work with trace amounts that are below the DNA content of a single cell. Specificity of the assay was tested with DNA extracts from Taxaceae and selected representatives from other related plant families (Cephalotaxaceae, Cupressaceae and Pinaceae). When combined with the commercial Phire® Plant Direct PCR Kit (Finnzymes), the primers allowed application of a two-step cycling protocol (without the annealing step), and because direct PCR requires only little sample pre-treatment, results from PCR could be obtained within 1.5 h after analysis had begun. Direct PCR was performed with diluted gastric content from the forensic case. Amplification products of the expected size were purified and sequenced. Sequence data were subjected to Basic Local Alignment Search Tool analysis and affiliated with ITS1 from Taxus spp.

Aconitine involvement in an unusual homicide case

We describe a homicide complicated by an aconitine poisoning, which was initially thought to be a strangulation case. Routine toxicological analyses demonstrated only a small amount of alcohol in the blood and the urine. The case could not be clarified until 5 years after the event. A new element in the investigation made the wife the prime suspect, and finally, after thorough interrogation, she confessed her crime. She had mixed a decoction of three plants of Aconitum with red wine. Additional toxicological analyses, using the liquid chromatography-tandem mass spectrometry (LC-MS-MS) technique demonstrated 810 ng/ml of aconitine in urine, 6.5 ng/g in liver and 1.3 ng/g in the kidneys. Even though aconitine poisoning is still rare in Europe, it should be taken into account in suicides and homicides, particularly in unclarified cases.

A comparative study of five fatal cases of Taxus poisoning

The study presents five fatal cases of poisoning with Taxus spp., all of which were suicides of young people aged between 16 and 26 years. Yew leaves were consumed in four fatalities, whereas a mash from Taxus was ingested in one case. No relevant concentrations of alcohol, narcotic drugs, and pharmaceuticals were determined in postmortem toxicological screening. At forensic autopsy, a widely dilated pupil was found in two decedents. Furthermore, autopsy showed unspecific findings of intoxication in all cases: acute blood congestion of lungs, liver, kidney, and brain as well as dilated cardiac ventricles. No signs of violence could be found in any of the fatalities. Yew leaves were identified in four cases in the stomach and duodenum. 3,5-Dimethoxyphenol, the aglycon of the Taxus ingredient taxicatine, was determined as toxicological evidence for the absorption of yew ingredients. Taxus intoxication could be confirmed by 3,5-dimethoxyphenol concentrations in cardiac blood between 31 and 528 ng/ml for all cases. 3,5-Dimethoxyphenol was also detected in stomach contents as well as in urine, liver, kidneys, and brain samples. Based on the different concentrations of 3,5-dimethoxyphenol determined in the cardiac blood samples, it was concluded that the form of ingestion plays a decisive role in the process of poisoning. Finally, a toxic range for Taxus poisoning based on 3,5-dimethoxyphenol as marker substance is proposed as orientation.