SciCombinator

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Concept: Brugmansia

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Plants have evolved many defenses against insect herbivores, including numerous chemicals that can reduce herbivore growth, performance, and fitness. One group of chemicals, the tropane alkaloids, is commonly found in the nightshade family (Solanaceae) and has been thought to reduce performance and fitness in insects. We examined the effects of the tropane alkaloid scopolamine, the alkaloid constituent of Datura wrightii, which is the most frequent host plant for the abundant and widespread insect herbivore Manduca sexta in the southwestern United States. We exposed caterpillars of two different species to scopolamine: M. sexta, which has a shared evolutionary history with Datura and other solanceous plants, and Galleria mellonella, which does not. We showed that the addition of ecologically-realistic levels of scopolamine to both the diet and the hemolymph of these two caterpillar species (M. sexta and G. mellonella) had no effect on the growth of either species. We also showed that M. sexta has no behavioral preference for or against scopolamine incorporated into an artificial diet. These results are contrary to other work showing marked differences in performance for other insect species when exposed to scopolamine, and provide evidence that scopolamine might not provide the broad-spectrum herbivore resistance typically attributed to it. It also helps to clarify the coevolutionary relationship between M. sexta and one of its main host plants, as well as the physiological mechanism of resistance against scopolamine.

Concepts: Evolution, Insect, Plant, Solanaceae, Cocaine, Tropane, Scopolamine, Brugmansia

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A closer monitoring of tropane alkaloids (TA) in foods is now recommended by the European Commission, following a series of alerts related to the contamination of buckwheat with weeds of the genus Datura. A novel, accurate UHPLC-MS/MS method was developed and validated for the rapid detection of scopolamine and atropine in buckwheat foods. A suitable extraction protocol was set up to maximize recoveries and detection limits in different raw, processed and baked foods. The method offers good performances in terms of sensitivity, accuracy and precision, with LOQs at 0.04 and 0.10µg/kg. The established method is suitable for routine determination of trace levels of TA and was applied to 26 different buckwheat-derived organic foods, detecting TA in 3 samples (13.9-83.9µg/kg for atropine and 5.7-10.4µg/kg for scopolamine). Only in one case the level of contamination was relevant in terms of food safety.

Concepts: European Union, Food, European Commission, Accuracy and precision, Solanaceae, Experimental uncertainty analysis, Tropane, Brugmansia

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A unilaterally fixed mydriasis, also known as a ‘blown pupil,’ is considered an ominous sign concerning for intracranial pathology. Causes of anisocoria can range from benign to immediately life-threatening. When a patient presents with anisocoria, the concern for a fatal diagnosis leads the clinician to obtain numerous tests, many of which may be unnecessary. The authors present a case of a healthy woman in her 30s who presented with an acute unilateral mydriasis likely secondary to inadvertent contact with a scopolamine patch. On examination, she had no other neurological deficits. Further investigation did not reveal any abnormality. In the event of a patient with an isolated mydriasis in an otherwise healthy and conversant patient with no other neurological deficits, it is essential to rule out other causes before pursuing aggressive and unnecessary testing and treatment.

Concepts: Hospital, Medical diagnosis, Pupil, Anisocoria, Mydriasis, Tropicamide, Scopolamine, Brugmansia

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Tropane alkaloids are a wide group of substances that comprises more than 200 compounds occurring especially in the Solanaceae family. The main aim of this study is the development of a method for the analysis of the principal tropane alkaloids as atropine, scopolamine, anisodamine, tropane, tropine, littorine, homatropine, apoatropine, aposcopolamine, scopoline, tropinone, physoperuvine, pseudotropine and cuscohygrine in cereals and related matrices. For that, a simple solid-liquid extraction was optimized and a liquid chromatographic method coupled to a single stage Exactive-Orbitrap was developed. The method was validated obtaining recoveries in the range of 60-109% (except for some compounds in soy), precision values (expressed as relative standard deviation) lower than 20% and detection and quantification limits equal to or lower than 2 and 3μg/kg respectively. Finally, the method was applied to the analysis of different types of samples as buckwheat, linseed, soy and millet, obtaining positives for anisodamine, scopolamine, atropine, littorine and tropinone in a millet flour sample above the quantification limits, whereas atropine and scopolamine were detected in a buckwheat sample, below the quantification limit. Contaminated samples with Solanaceaes seeds (Datura Stramonium and Brugmansia Arborea) were also analysed, detecting concentrations up to 693μg/kg (scopolamine) for contaminated samples with Brugmansia seeds and 1847μg/kg (atropine) when samples were contaminated with Stramonium seeds.

Concepts: Chromatography, Solanaceae, Atropine, Cocaine, Hyoscyamine, Datura, Tropane, Brugmansia

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Tropane alkaloids are toxic secondary metabolites produced by Solanaceae plants. Among them, plants from Datura genus produce significant amounts of scopolamine and hyoscyamine; the latter undergoes racemization to atropine during isolation. Because of their biological importance, toxic properties and commonly reported food and animal feed contamination by different Datura sp. organs, there is a constant need for reliable methods for the analysis of tropane alkaloids in many matrices. In the current study, three extraction and sample-clean up procedures for the determination of scopolamine and atropine in plant material were compared in terms of their effectiveness and repeatability. Standard liquid-liquid extraction (LLE) and EXtrelut(®) NT 3 columns were used for the sample clean-up. Combined ultrasound-assisted extraction and 24h static extraction using ethyl acetate, followed by multiple LLE steps was found the most effective separation method among tested. However, absolute extraction recovery was relatively low and reached 45-67% for atropine and 52-73% for scopolamine, depending on the compound concentration. The same method was also the most effective one for the isolation of target compounds from Datura stramonium leaves. EXtrelut(®) columns, on the other hand, displayed relatively low effectiveness in isolating atropine and scopolamine from such a complex matrix and hence could not be recommended. The most effective method was also applied to the extraction of alkaloids from roots and stems of D. stramonium. Quantitative analyses were performed using validated method based on gas chromatography with flame ionization detector (GC-FID). Based on the results, the importance of the proper selection of internal standards in the analysis of tropane alkaloids was stressed out.

Concepts: Solanaceae, Atropine, Hyoscyamine, Datura, Datura stramonium, Tropane, Scopolamine, Brugmansia

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Brugmansia arborea is a woody plant species that produces tropane alkaloids (TAs). The gene encoding tropine-forming reductase or tropinone reductase I (BaTRI) in this plant species was functionally characterised. The full-length cDNA of BaTRI encoded a 272-amino-acid polypeptide that was highly similar to tropinone reductase I from TAs-producing herbal plant species. The purified 29kDa recombinant BaTRI exhibited maximum reduction activity at pH 6.8-8.0 when tropinone was used as substrate; it also exhibited maximum oxidation activity at pH 9.6 when tropine was used as substrate. The Km, Vmax and Kcat values of BaTRI for tropinone were 2.65mM, 88.3nkatmg(-1) and 2.93S(-1), respectively, at pH 6.4; the Km, Vmax and Kcat values of TRI from Datura stramonium (DsTRI) for tropinone were respectively 4.18mM, 81.20nkatmg(-1) and 2.40S(-1) at pH 6.4. At pH 6.4, 6.8 and 7.0, BaTRI had a significantly higher activity than DsTRI. Analogues of tropinone, 4-methylcyclohexanone and 3-quinuclidinone hydrochloride, were also used to investigate the enzymatic kinetics of BaTRI. The Km, Vmax and Kcat values of BaTRI for tropine were 0.56mM, 171.62nkat.mg(-1) and 5.69S(-1), respectively, at pH 9.6; the Km, Vmax and Kcat values of DsTRI for tropine were 0.34mM, 111.90nkatmg(-1) and 3.30S(-1), respectively, at pH 9.6. The tissue profiles of BaTRI differed from those in TAs-producing herbal plant species. BaTRI was expressed in all examined organs but was most abundant in secondary roots. Finally, tropane alkaloids, including hyoscyamine, anisodamine and scopolamine, were detected in various organs of B. arborea by HPLC. Interestingly, scopolamine constituted most of the tropane alkaloids content in B. arborea, which suggests that B. arborea is a scopolamine-rich plant species. The scopolamine content was much higher in the leaves and stems than in other organs. The gene expression and TAs accumulation suggest that the biosynthesis of hyoscyamine, especially scopolamine, occurred not only in the roots but also in the aerial parts of B. arborea.

Concepts: DNA, Gene expression, Atropine, Hyoscyamine, Datura, Tropane alkaloid, Scopolamine, Brugmansia

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The family Solanaceae includes several melliferous plants, which tend to produce copious amounts of nectar. Floral nectar is a chemically complex aqueous solution, dominated by sugars, but minor components such as amino acids, proteins, flavonoids and alkaloids are present as well. This study aimed at analysing the protein and alkaloid profile of the nectar in seven solanaceous species. Proteins were examined with SDS-PAGE and alkaloids were analyzed with HPLC. The investigation of protein profile revealed significant differences in nectar-protein patterns not only between different plant genera, but also between the three Nicotiana species investigated. SDS-PAGE suggested the presence of several Nectarin proteins with antimicrobial activity in Nicotiana species. The nectar of all tobacco species contained the alkaloid nicotine, N. tabacum having the highest nicotine content. The nectar of Brugmansia suaveolens, Datura stramonium, Hyoscyamus niger and Lycium barbarum contained scopolamine, the highest content of which was measured in B. suaveolens. The alkaloid concentrations in the nectars of most solanaceous species investigated can cause deterrence in honeybees, and the nectar of N. rustica and N. tabacum can be considered toxic for honeybees.

Concepts: Amino acid, Nicotine, Solanaceae, Nicotiana, Atropine, Hyoscyamine, Datura, Brugmansia

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Brugmansia, commonly referred to as angel’s trumpet (AT), has been become popular in Korea as an ornamental shrub. However, it is not generally known by the public that this plant contains tropane alkaloids, and that ingestion of AT can lead to anticholinergic poisoning.

Concepts: Alkaloids, Tree, Atropine, Cocaine, Tropane, Tropane alkaloid, Scopolamine, Brugmansia

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Four new flavonol glycosides were isolated from the leaves of Brugmansia suaveolens: kaempferol 3-O-β-D-glucopyranosyl-(1'“→2”)-O-α-L-arabinopyranoside (1), kaempferol 3-O-β-D-glucopyranosyl-(1'“→2”)-O-α-L-arabinopyranoside-7-O-į-D-gluco-pyranoside (2), kaempferol 3-O-β-D-[6'“-O-(E-caffeoyl)]-glucopyranosyl-(1”‘→2’‘)-O-α-l-arabinopyranoside-7-O-β-D-glucopyranoside (3), and kaempferol 3-O-β-D-[2’“-O-(E-caffeoyl)]-glucopyranosyl-(1”‘→2’‘)-O-α-l-arabinopyranoside-7-O-β-D-glucopyranoside (4). The structure elucidation was performed by MS, 1D and 2D NMR analyses.

Concepts: Quercetin, Flavonoid, Brugmansia