Quantitative LC–MS determination of strychnine in urine after ingestion of a Strychnos nux-vomica preparation and its consequences in doping control

The Production and Evaluation of an Electrochemical Sensors for Strychnine and Its Main Metabolite Strychnine N-Oxide for Their Use in Biological Samples

Strychnine (STN) and its major metabolite Strychnine N-Oxide (SNO) were examined electrochemically. Both parent compounds and its major metabolite showed electroactivity on glassy carbon electrodes using CV and DPV techniques. One oxidation peak at 1008 mV was observed for STN with the optimum peak intensity at pH 7. SNO produced two oxidation peaks, at 617 mV and 797 mV, at pH 5. The peaks demonstrated irreversible behaviour and the irreversibility of the system was confirmed at different scan rates. A calibration curve was produced for both CV and DPV measurements and the sensitivity of the proposed EC method was good compared with previous electrochemical and non-electrochemical methods. The precision of oxidation peak of STN using the STN-MIP method produced a maximum value of 11.5% and 2.32% for inter-day and intraday %RSD, respectively. The average% recovery was around 92%. The electrochemical method has been successfully applied to the determination of STN in spiked plasma and urine samples. For SNO, both anodic peaks of SNO demonstrated irreversible behaviour. A different sweep rate was used for calculating the number of ‘transfer electrons’ in the system; based on this, the mechanism of oxidation reaction was proposed. Calibration curves for both oxidative peaks were produced using DPV measurements. The second anodic peak demonstrated high linearity and precision with %RSD < 1.96%.

Undeclared Doping Substances are Highly Prevalent in Commercial Sports Nutrition Supplements

Sports nutrition supplements have previously been reported to contain undeclared doping substances. The use of such supplements can lead to general health risks and may give rise to unintentional doping violations in elite sports. To assess the prevalence of doping substances in a range of high-risk sports nutrition supplements available from Dutch web shops. A total of 66 sports nutrition supplements - identified as potentially high-risk products claiming to modulate hormone regulation, stimulate muscle mass gain, increase fat loss, and/or boost energy - were selected from 21 different brands and purchased from 17 web shops. All products were analyzed for doping substances by the UK life sciences testing company LGC, formerly known as the Laboratory of the Government Chemist, using an extended version of their ISO17025 accredited nutritional supplement screen. A total of 25 out of the 66 products (38%) contained undeclared doping substances, which included high levels of the stimulants oxilofrine, β-methylphenethylamine (BMPEA) and N,β-dimethylphenethylamine (NBDMPEA), the stimulant 4-methylhexan-2-amine (methylhexaneamine, 1,3-dimethylamylamine, DMAA), the anabolic steroids boldione (1,4-androstadiene-3,17-dione) and 5-androstene-3β,17α-diol (17α-AED), the beta-2 agonist higenamine and the beta-blocker bisoprolol. Based upon the recommended dose and the potential variability of analyte concentration, the ingestion of some products identified within this study could pose a significant risk of unintentional doping violations. In addition to inadvertent doping risks, the prescribed use of 3 products (4.5%) could likely impose general health risks.

An unusual case of strychnine poisoning

Strychnine-related death has been described since the 19th century. This alkaloid was discovered in 1818. Historically, strychnine was used by the South-East Asian autochthones on their arrows. However, its production was modified by legislation, which was used to protect people against accidental intoxications. Here, we present the case of a 69-year-old man who was found dead at home. During the autopsy, we found a blue substance in the stomach. Toxicological analysis measured strychnine at 0.29 μg/mL in the blood sample, which is a relatively low level in comparison with the results given in the literature. However, histologic examination and toxicological findings permitted the conclusion of strychnine poisoning.

A new method for the simultaneous analysis of strychnine and brucine in Strychnos nux-vomica unprocessed and processed seeds using a carbon-paste electrode modified with multi-walled carbon nanotubes

INTRODUCTION

Strychnos nux-vomica L. (Loganiaceae), widely used in folk medicine, is grown extensively in southern Asian countries. Its major bioactive constituents are strychnine and brucine, which are frequently used in traditional herbal medicines for treatment of nervous diseases, vomiting and traumatic pain.

OBJECTIVE

A new method using a carbon-paste electrode modified with multi-walled carbon nanotubes (CNT/CPE) was developed and validated for single or simultaneous determination of strychnine and brucine in Strychnos nux-vomica seeds. Additionally, an environmentally friendly method was successfully applied to reduce the levels of strychnine and brucine in seeds.

MATERIALS AND METHODS

Cyclic voltammetry, chronocoulometry and differential pulse voltammetry were used with multi-walled carbon nanotube modified carbon-paste electrodes.

RESULTS

The peak currents increase linearly with the strychnine and brucine concentrations in the ranges of 50-1000 and 5-355 µ m, and the detection limits for strychnine and brucine were 0.43 and 0.28 µ m, respectively. Of the processing methods used, the greatest reduction in the strychnine and brucine levels was observed in samples processed using milk and saltwater.

CONCLUSION

A new, sensitive and selective method was developed for the measurement of strychnine and brucine. This method was successfully applied to the determination of strychnine and brucine in unprocessed and processed Strychnos nux-vomica seed.

beta-Adrenergic stimulation

Two groups of substances which stimulate the adrenergic system are listed as prohibited by the World Anti-Doping Agency. Stimulants are prohibited in-competition only and beta(2)-agonists are prohibited in- and out-of-competition. While beta(2)-agonists act directly on the target receptors, sympathomimetic amines can exert their action directly and indirectly. Due to differences in pharmacology but mainly due to differences in administered dose, differences in detection methods between both groups of substances exist although preparation is similar and consists of an extraction at basic pH. Gas chromatography coupled to mass spectrometry has been the detection methodology of choice for several decades. However, the importance of liquid chromatography-mass spectrometry as a preferred detection methodology is rapidly increasing, especially for the detection of beta(2)-agonists and new additions to the list of prohibited stimulants, such as modafinil. Pharmacology, metabolism and detection of both groups of prohibited substances will be discussed.