Tropane alkaloid analysis by chromatographic and electrophoretic techniques: An update

Alkaloids in food: a review of toxicity, analytical methods, occurrence and risk assessments

Alkaloids have been utilized by humans for years. They have diverse applications in pharmaceuticals. They have been proven to be effective in treating a number of diseases. They also form an important part of regular human diets, as they are present in food items, food supplements, diet ingredients and food contaminants. Despite their obvious importance, these alkaloids are toxic to humans. Their toxicity is dependent on a range of factors, such as specific dosage, exposure time and individual properties. Mild toxic effects include nausea, itching and vomiting while chronic effects include paralysis, teratogenicity and death. This review summarizes the published studies on the toxicity, analytical methods, occurrence and risk assessments of six major alkaloid groups that are present in food, namely, ergot, glycoalkaloids, purine, pyrrolizidine, quinolizidine and tropane alkaloids.

Gastrointestinal bioaccessibility and fiber mitigation of tropane alkaloids assessed on tea and cookies by in vitro digestion

BACKGROUND

Tropane alkaloids (TAs) are toxic compounds with a high anticholinergic effect. They have been widely analyzed in food samples, but their fate in the gastrointestinal tract has not been evaluated yet.

RESULTS

In this study, static in vitro digestion was performed to assess gastrointestinal bioaccessibility of the most common TAs on tea and home-made cookies. Cookies enriched with dietary fiber (pectin, arabinogalactan, and κ-carrageenan) were also tested to evaluate their influence on TA bioaccessibility. Two extraction methods and a liquid chromatography-mass spectrometry method were optimized and validated. Bioaccessibility for tea (60-105%) was higher than for cookies (39-93%) (P = 0.001-0.002), which indicates TAs could be more easily absorbed when they are contaminating tea. Digestion of cookies enriched with 50 g kg^-1 of different fibers showed that, although no significant changes were observed in the gastric phase (P = 0.084-0.920), duodenal bioaccessibility was significantly reduced (P = 0.008-0.039). Pectin was the fiber with a better mitigation effect for all the compounds.

CONCLUSION

TAs bioaccessibility was determined after in vitro digestion of contaminated tea and cookies. Dietary fiber seems to be a promising mitigation strategy, significantly reducing TA bioaccessibility percentages. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Occurrence and Chemistry of Tropane Alkaloids in Foods, with a Focus on Sample Analysis Methods: A Review on Recent Trends and Technological Advances

Tropane alkaloids (TAs) are natural toxins produced by different plants, mainly from the Solanaceae family. The interest in TAs analysis is due to the serious cases of poisoning that are produced due to the presence of TA-producing plants in a variety of foods. For this reason, in recent years, different analytical methods have been reported for their control. However, the complexity of the matrices makes the sample preparation a critical step for this task. Therefore, this review has focused on (a) collecting the available data in relation to the occurrence of TAs in foods for human consumption and (b) providing the state of the art in food sample preparation (from 2015 to today). Regarding the different food categories, cereals and related products and teas and herbal teas have been the most analyzed. Solid–liquid extraction is still the technique most widely used for sample preparation, although other extraction and purification techniques such as solid-phase extraction or QuEChERS procedure, based on the use of sorbents for extract or clean-up step, are being applied since they allow cleaner extracts. On the other hand, new materials (molecularly imprinted polymers, mesostructured silica-based materials, metal–organic frameworks) are emerging as sorbents to develop effective extraction and purification methods that allow lower limits and matrix effects, being a future trend for the analysis of TAs.

Pipes and Potions: Testing the Efficacy of European Folk Preparation Methods for Anticholinergic Solanaceae Plants

The present article sought to evaluate the efficiency of various folk preparation methods commonly used in Europe for employing anticholinergic Solanaceae plants. The study aimed to uncover which folk methods were effective for the extraction of the anticholinergic tropane alkaloids of these plants, atropine and scopolamine. The folk extractions that were tested sought to simulate the preparation of teas, cold-water infusions, unguents, tinctures, fortified wines, and smoking. All preparation types and a control were then put through an extraction process to see what amount of the alkaloids had been maintained. These extractions were then analysed using high-performance liquid chromatography (HPLC). Cold- and hot-water preparations, tinctures, and fortified wines all proved to be effective means of extracting atropine and scopolamine from plant material under conditions seen in folk usage. Smoking and the oil-based unguent, however, yielded no alkaloids, suggesting a lack of efficiency for these preparations, a problem with our methodology, or possible chemical changes and losses associated with the preparation procedure.

The impact of chirality on the analysis of alkaloids in plant

Most of the alkaloids are chiral compounds and are clinically administered as the racemic mixture, even though its enantiomers have been known to exert different pharmacological activity. The determination of the enantiomeric composition of alkaloid-containing plants is subject to severe attention from pharmacological and toxicological points of view. This review gives an overview of the chiral analysis of alkaloids that were used in theoretical studies and applications for plants in recent years.

Thermal (In)stability of Atropine and Scopolamine in the GC-MS Inlet

The intoxication due to unintentional or intentional ingestion of plant material containing tropane alkaloids is quite frequent. GC-MS method is still widely used for the identification of these toxicologically important substances in human specimen. During general unknown analysis, high temperature of inlet, at least 270 °C, is commonly used for less volatile substances. Unfortunately, both tropanes are thermally unstable and could be overlooked due to their degradation. The temperature-related degradation of tropanes atropine and scopolamine was systematically studied in the inlet of a GC-MS instrument in the range 110–250 °C by increments of 20 °C, additionally also at 275 °C, and in different solvents. At inlet temperatures not higher than 250 °C, the degradation products were formed by elimination of water and cleavage of atropine’s ester bond. At higher temperatures, elimination of formaldehyde became predominant. These phenomena were less pronounced when ethyl acetate was used instead of methanol, while n-hexane proved unsuitable for several reasons. At an inlet temperature of 275 °C, tropanes were barely detectable. During systematic toxicological analysis, any tropanes’ degradation products should indicate the possible presence of atropine and/or scopolamine in the sample. It is not necessary to prepare thermally stable derivatives for confirmation. Instead, the inlet temperature can be decreased to 250 °C, which diminishes their degradation to a level where their detection and identification are possible. This was demonstrated in several case studies.

Indirect competitive enzyme-linked immunosorbent assay based on a broad-spectrum monoclonal antibody for tropane alkaloids detection in pig urine, pork and cereal flours

In this study, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) based on a broad-spectrum monoclonal antibody for tropane alkaloids (TAs) was established for the rapid screening of atropine, scopolamine, homatropine, apoatropine, anisodamine, anisodine and L-hyoscyamine residues in pig urine, pork and cereal flour samples through a simple sample preparation procedure. The half inhibitory concentrations of atropine, homatropine, L-hyoscyamine, apoatropine, scopolamine, anisodamine and anisodine were 0.05, 0.07, 0.14, 0.14, 0.24, 5.30 and 10.15 ng mL-1, respectivelyThe detection and quantitative limits of this method for TAs in samples were 0.18-73.18 and 0.44-74.77 μg kg-1. The spiked recoveries ranged from 69.88% to 147.93%, and the coefficient of variations were less than 14%. Good correlation (R2 = 0.9929) between the results of the ic-ELISA and the high performance liquid chromatography-tandem mass spectrometry support the reliability of the developed ic-ELISA method.

Simultaneous quantification of three tropane alkaloids in goji berries by cleanup of the graphene/hexagonal boron nitride hybrids and ultra-high-performance liquid chromatography tandem mass spectrometry

A modified quick, easy, cheap, effective, rugged and safe method was established for simultaneous determination of atropine, anisodamine, and scopolamine in goji berries by using ultra-high-performance liquid chromatography with tandem mass spectrometry. The graphene/hexagonal boron nitride hybrids were prepared and first applied as a cleanup adsorbent. Compared to classical cleanup adsorbent (C₁₈ ), the graphene/hexagonal boron nitride hybrids as adsorbent had better extraction efficiency for the detection of analytes. Under the optimal conditions, the proposed analytical method achieved satisfactory linearity (R²  > 0.995), and obtained desirable recoveries ranged from 77.4 to 94.0% with the relative standard deviation of 1.2-6.1% at the concentration levels of 3.2-13.4 µg/kg. The limits of quantitation of atropine, anisodamine, and scopolamine were, respectively, 3.2, 4.6, and 4.5 µg/kg with linearity ranged from 3.2 to 25.4 µg/kg. The modified quick, easy, cheap, effective, rugged, and safe sample preparation with ultra-high-performance liquid chromatography and tandem mass spectrometry method was successfully applied to evaluate the safety of goji berries collected from 30 plant areas in China, suggesting its applicability and suitability for the routine analysis of three tropane alkaloids in goji berries.

Dark Classics in Chemical Neuroscience: An Evidence-Based Systematic Review of Belladonna

Belladonna has diverse pharmacotherapeutic properties with a shadowy history of beauty, life, and death. Alkaloids present in belladonna have anti-inflammatory, anticholinergic, antispasmodic, mydriatic, analgesic, anticonvulsant, and antimicrobial activities, which makes it widely applicable for the treatment of various diseases. However, because of its associated toxicity, the medicinal use of belladonna is debatable. Therefore, an evidence-based systematic review was planned to elucidate the pharmacotherapeutic potential of belladonna. A comprehensive literature search was performed in PubMed, MEDLINE, the Cochrane database, Embase, and ClinicalTrials.gov using the keywords "belladonna", "belladonna and clinical trials", and "safety and efficacy of belladonna". Articles published from 1965 to 2020 showing the efficacy of belladonna in diverse clinical conditions are included. The quality of evidence was generated using the GRADE approach, and 20 studies involving 2302 patients were included for the systematic review. Our analyses suggest that belladonna treatment appears to be safe and effective in various disease conditions, including acute encephalitis syndrome, urethral stent pain, myocardial ischemia injury, airway obstructions during sleep in infants, climacteric complaints, irritable bowel syndrome, and throbbing headache. However, better understanding of the dosage and the toxicity of tropane alkaloids of belladonna could make it an efficient remedy for treating diverse medical conditions.

Plant growth promoting N-alkyltropinium bromides enhance seed germination, biomass accumulation and photosynthesis parameters of maize (Zea mays)

N-Alkyltropinium bromides were synthesized and characterized as novel plant-growth promoting agents.

Separation and detection of tropane alkaloids in Anisodus tanguticus by capillary electrophoresis-electrochemiluminescence

Anisodine and anisodamine in different parts of Anisodus tanguticus are separated and determined using a chemically modified Pt electrode.

Intra- and inter-laboratory validation of a dipstick immunoassay for the detection of tropane alkaloids hyoscyamine and scopolamine in animal feed

Tropane alkaloids (TAs) are toxic secondary metabolites produced by plants of, inter alia, the genera Datura (thorn apple) and Atropa (deadly nightshade). The most relevant TAs are (-)-L-hyoscyamine and (-)-L-scopolamine, which act as antagonists of acetylcholine muscarinic receptors and can induce a variety of distinct toxic syndromes in mammals (anti-cholinergic poisoning). The European Union has regulated the presence of seeds of Datura sp. in animal feeds, specifying that the content should not exceed 1000 mg kg(-1) (Directive 2002/32/EC). For materials that have not been ground, visual screening methods are often used to comply with these regulations, but these cannot be used for ground materials and compound feeds. Immunological assays, preferably in dipstick format, can be a simple and cost-effective approach to monitor feedstuffs in an HACCP setting in control laboratories. So far no reports have been published on immunoassays that are capable of detecting both hyoscyamine and scopolamine with equal sensitivity and that can be used, preferably in dipstick format, for application as a fast screening tool in feed analysis. This study presents the results obtained for the in-house and inter-laboratory validation of a dipstick immunoassay for the detection of hyoscyamine and scopolamine in animal feed. The target level was set at 800 µg kg(-1) for the sum of both alkaloids. By using a representative set of compound feeds during validation and a robust study design, a reliable impression of the relevant characteristics of the assay could be obtained. The dipstick test displayed similar sensitivity towards the two alkaloids and it could be concluded that the test has a very low probability of producing a false-positive result at blank level or a false-negative result at target level. The assay can be used for monitoring of TAs in feedstuffs, but has also potential as a quick screening tool in food- or feed-related poisonings.

Simultaneous detection of 22 toxic plant alkaloids (aconitum alkaloids, solanaceous tropane alkaloids, sophora alkaloids, strychnos alkaloids and colchicine) in human urine and herbal samples using liquid chromatography-tandem mass spectrometry

A liquid chromatography-tandem mass spectrometry method for simultaneous detection of 22 toxic plant alkaloids, including aconitum alkaloids and their hydrolyzed products (aconitine, hypaconitine, mesaconitine, yunaconitine, crassicauline A, benzoylaconine, benzoylmesaconine, benzoylhypaconine, deacetylyunaconitine, deacetylcrassicauline A), solanaceous tropane alkaloids (atropine, anisodamine, scopolamine, anisodine), sophora alkaloids (matrine, sophoridine, oxymatrine, cytisine, N-methylcytisine), strychnos alkaloids (brucine, strychnine) and colchicine, in herbal and urine samples was developed and validated. Following sample preparation by liquid-liquid extraction, chromatographic separation was achieved on Eclipse XDB C8 column. Identification was based on two multiple reaction monitoring transitions and the relative ion intensity. Method selectivity was demonstrated. The limits of detection were 5ng/mL for all analytes, except 50ng/mL for cytisine. The herbal matrix effects ranged from 89% to 118%, whereas the urine matrix effects were between 91% and 109% for all analytes except cytisine (57%) and N-methylcytisine (67%). The urine extraction recovery ranged from 74% to 110% for all analytes, except cytisine (15%) and oxymatrine (30%). With the good extraction efficiency of the other major sophora alkaloids, the relatively low extraction recovery of the minor sophora alkaloids cytisine and oxymatrine did not affect identification of sophora alkaloids as a group. Carry-over was minimal at less than 0.1%. The method was successfully applied in analysis of 170 cases of suspected herbal poisoning, with aconitum alkaloids, sophora alkaloids, solanaceous tropane alkaloids, and strychnos alkaloids being detected in 53, 42, 18, and 6 cases, respectively.

Rapid resolution liquid chromatography for monitoring the quality of stockpiled atropine preparations for injection

We describe a rapid resolution liquid chromatography (RRLC) method for analyzing atropine sulfate, its degradation products (tropic acid, apoatropine, atropic acid) and other components (e.g. phenol, methylparaben) in injectable medicines that are used by the German armed forces in emergency situations. Chromatography is performed using an acetonitrile/phosphate buffer gradient (pH = 1.0) and an RP 18 column (50 x 4.6 mm, 1.8 µm) with the detection wavelength set at 220 nm. The concentration of the active ingredient (atropine sulfate) in the tested products ranges from about 1 mg•ml(-1) to 10 mg•ml(-1) . The concentrations of the detected degradation products range from 0.2% to 4.7% (tropic acid) in relation to the active pharmaceutical ingredient (API). Using shorter separation columns and smaller particle sizes of the stationary phase improved analysis time from 40 to 10 min and reduced the consumption of solvents by approximately 75%. Owing to the pressure conditions (< 200 bar), UHPLC (ultra high performance liquid chromatography) systems are not needed. Comparison of the atropine and tropic acid results obtained with the previously used HPLC (high performance liquid chromatography) method of the MAH (marketing authorization holder) show that there is no indication of a significant difference between the two methods.

Determination of Atropine Sulfate in Human Urines by Capillary Electrophoresis Using Chemical Modified Electrode as Electrochemiluminescence Sensor

A Ru(bpy)3 2+-based electrochemiluminescence (ECL) detection coupled with capillary electrophoresis (CE) was developed for the determination of atropine sulfate on the basis of an Eu-PB modified platinum electrode as the working electrode. The analyte was injected to separation capillary of 50 cm length (25 μm i.d., 360 μm o.d.) by electrokinetic injection for 10 s at 10 kV. Parameters related to the separation and detection were discussed and optimized. It was proved that 10 mM phosphate buffer at pH 8.0 could achieve the most favorable resolution, and the high sensitivity of detection was obtained by using the detection potential at 1.15 V and 5 mM Ru(bpy)3 2+in 80 mM phosphate buffer at pH 8.0 in the detection reservoir. Under the optimized conditions, the ECL peak area was in proportion to atropine sulfate concentration in the range from 0.08 to 20 μg⋅mL−1with a detection limit of 50 ng⋅mL−1(3σ). The relative standard derivations of migration time and peak area were 0.81 and 3.19%, respectively. The developed method was successfully applied to determine the levels of atropine sulfate in urine samples of patients with recoveries between 90.9 and 98.6%.