Unexpected occurrence of caffeine in sleep-inducing herbal teas.

Caffeine acts as a weak psychostimulant and is known to cause trouble with sleeping. Therefore, the presence of caffeine in sleep-aid herbal teas was somewhat surprising, and confirmatory investigations were conducted to exclude any possible misidentification. The botanicals of the sedative mixtures were analysed individually by ultra performance liquid chromatography (UPLC) coupled with a time-of-flight high-resolution mass spectrometer (TOF-HRMS), and caffeine was detected in linden (Tilia spp.) extracts. The presence of caffeine was unambiguously confirmed by means of its characteristic mass spectrum acquired during direct analyses of powdered linden by thermal desorption coupled to a GC×GC-TOF-MS. Caffeine content was determined in 11 linden-based samples, with a validated UPLC-MS/MS method using two mass transitions. Concentrations were between traces and 110 mg kg(-1) in the herbal material while those in the corresponding prepared sleep-inducing hot beverages ranged from traces to 226 µg per cup.

Survey of pyrrolizidine alkaloids in teas and herbal teas on the Swiss market using HPLC-MS/MS.

Pyrrolizidine alkaloids (PAs) are a large class of natural compounds amongst which the esterified 1,2-unsaturated necine base is toxic for humans and livestock. In the present study, a method was developed and validated for the screening and quantification of nine PAs and one PA N-oxide in teas (Camellia sinensis (L.) O. Kuntze) and herbal teas (camomile, fennel, linden, mint, rooibos, verbena). Samples were analysed by HPLC on a RP-column, packed with sub-2 µm core-shell particles, and quantified using tandem mass spectrometry operating in the positive electrospray ionisation mode. These PAs and some of their isomers were detected in a majority of the analysed beverages (50/70 samples). In 24 samples, PA concentrations were above the limit of quantification and the sum of the nine targeted PAs was between 0.021 and 0.954 µg per cup of tea. Thus, in some cases, total concentrations exceed the maximum daily intake recommended by the German Federal Institute for Risk Assessment and the UK's Committee On Toxicity (i.e. 0.007 µg kg(-1) bw).

Screening and determination of sibutramine in adulterated herbal slimming supplements by HPTLC-UV densitometry.

The adulteration of herbal supplements is of growing importance, especially when they contain undeclared compounds like sibutramine that are unsafe drugs. Sibutramine was withdrawn from US and European markets in 2010. In this study, an HPTLC-UV densitometric method was developed for the quantification of sibutramine in herbal diet foods. Sample extracts were directly applied onto HPTLC silica gel plates and separated with a mobile phase made of a toluene-methanol mixture. Sibutramine was quantified at 225 nm and its unequivocal identification was confirmed by MS using a TLC-MS interface. During two surveys, 52 weight loss supplements obtained via the Internet were screened. Half of those were adulterated with sibutramine at amounts reaching up to 35 mg per capsule. The results of this validated HPTLC method were compared with those obtained by HPLC-UV and HPLC-MS/MS. The results were not significantly different with the three methods.

Analysis of the neurotoxin anisatin in star anise by LC-MS/MS.

The aim of this work was to develop an analytical method capable of determining the presence of anisatin in star anise. This neurotoxin may induce severe side effects such as epileptic convulsions. It is therefore of prime importance to have rapid and accurate analytical methods able to detect and quantify anisatin in samples that are purportedly edible star anise. The sample preparation combined an automated accelerated solvent extraction with a solid-supported liquid-liquid purification step on EXtrelut®. Samples were analysed on a porous graphitic carbon HPLC column and quantified by tandem mass spectrometry operating in the negative ionisation mode. The quantification range of anisatin was between 0.2 and 8 mg kg⁻¹. The applicability of this validated method was demonstrated by the analysis of several Illicium species and star anise samples purchased on the Swiss market. High levels of anisatin were measured in Illicium lanceolatum, I. majus and I. anisatum, which may cause health concerns if they are misidentified or mixed with edible Illicium verum.

Characterization of positional and configurational tropane alkaloid isomers by combining GC with NPD, MS and FTIR.

A purified stem bark extract from Schizanthus grahamii was analyzed by combining capillary gas chromatography with a selective nitrogen phosphorus detector, mass spectrometry and Fourier transform infrared spectroscopy. Several positional and configurational tropane isomers were detected and their structural elucidation was tentatively determined based on mass spectra and confirmed by vapor phase infrared spectra. Electron impact mass spectra of the isomeric alkaloids were virtually superimposable, whereas the corresponding infrared spectra differed markedly. Retention indices were established under isothermal and temperature program conditions for further peak assignment and identification. In order to point out possible artifacts in the hot and surface-active injection port, different sample introduction techniques were evaluated, namely split, splitless and on-column injections.

Cocaine distribution in wild Erythroxylum species.

Cocaine distribution was studied in leaves of wild Erythroxylum species originating from Bolivia, Brazil, Ecuador, Paraguay, Peru, Mexico, USA, Venezuela and Mauritius. Among 51 species, 28 had never been phytochemically investigated before. Cocaine was efficiently and rapidly extracted with methanol, using focused microwaves at atmospheric pressure, and analysed without any further purification by capillary gas chromatography coupled to mass spectrometry. Cocaine was reported for the first time in 14 species. Erythroxylum laetevirens was the wild species with the highest cocaine content. Its qualitative chromatographic profile also revealed other characteristic tropane alkaloids. Finally, its cocaine content was compared to those of two cultivated coca plants as well as with a coca tea bag sample.