A. Stoll

Bio: A. Stoll is an academic researcher. The author has an hindex of 1, co-authored 1 publications receiving 52 citations.

Über Belichtungsprodukte von Mutterkornalkaloiden. 39. Mitteilung über Mutterkornalkaloide

Abstract: Es wurde die photochemisch hervorgerufene neuartige Reaktion von Ergotamin und andern lyserg- und isolysergsaurehaltigen Verbindungen in saurer, wasseriger Losung studiert und dabei festgestellt, dass sich unter dem Einfluss des Lichts an die Doppelbindung Δ9,10 des Rings D im Lyserg- bzw. Isolysergsaurerest 1 Mol Wasser anlagert. Die mit der Vorsilbe „Lumi” (Lumi-ergotamin, Lumi-ergotaminin, Lumi-lysergsaure etc.) bezeichneten Belichtungsprodukte sind in manchen ihrer Eigenschaften (z. B. Fehlen der Fluoreszenz im ultravioletten Licht, UV.-Absorptionsspektren) den entsprechenden Dihydroverbindungen, bei denen durch Anlagerung von Wasserstoff die Doppelbindung Δ9,10 ebenfalls abgesattigt ist, sehr ahnlich. Auch durch die Anlagerung von Wasser an die Doppelbindung Δ9,10 entsteht an C 10 ein neues Asymmetriezentrum, so dass je zwei stereoisomere Belichtungsprodukte, die wir in Beispielen fassen, analysieren und beschreiben konnten, entstehen. Durch die reduktive Spaltung von Lumi-ergotamin(I) zu Dihydro-lysergol(I) und Dihydro-isolysergol(I) ist wahrscheinlich gemacht, dass die Hydroxylgruppe bei den Lumi-Verbindungen an C 10 sitzt.

Scientific Opinion on Ergot alkaloids in food and feed

Abstract: The European Food Safety Authority (EFSA) was asked by the European Commission to deliver a scientific opinion on ergot alkaloids (EAs) in food and feed. EAs are produced by several members within the fungal orders of Hypocreales and Eurotiales. In Europe, Claviceps purpurea is the most widespread Claviceps species within the Hypocreales. A total of 20 558 analytical results for EAs in 1 716 food, 496 feed and 67 unprocessed grain samples were considered in this opinion. Based on the EAs identified in sclerotia of C. purpurea, and recent literature data, the EFSA Panel on Contaminants in the Food Chain (CONTAM Panel) based its risk assessment on the main C. purpurea EAs, namely ergometrine, ergotamine, ergosine, ergocristine, ergocryptine (which is a mixture of a- and s- isomers), ergocornine, and the corresponding –inine epimers. The CONTAM Panel performed estimates of both chronic and acute exposure for various age groups across European countries. A BMDL10 of 0.33 mg/kg b.w. per day was calculated for the incidence of tail muscular atrophy in a 13-week rat feeding study of ergotamine. This effect was considered representative of the vasoconstrictive effects of EAs and provided a suitable reference point for establishment of a group acute reference dose of 1 µg/kg body weight (b.w.) and a group tolerable daily intake of 0.6 µg/kg b.w. per day. The Panel concluded that whilst the available data do not indicate a concern for any population subgroup, the dietary exposure estimates relate to a limited number of food groups and a possible unknown contribution from other foods cannot be discounted. Estimates of exposure for livestock based on example diets and levels of EAs in cereal grains reported suggest that under normal conditions the risk of toxicosis is low.

Significance, chemistry and determination of ergot alkaloids: a review.

Abstract: The purpose of this paper is to summarize the most relevant and recent information available on ergot alkaloids. This includes information about their occurrence, toxicity, chemistry, statutory limits, and their significance in feed and food. Recently, in 2005, the European Food Safety Authority (EFSA) concluded that validated analytical methods for the quantification of ergot alkaloids in feed materials are needed. For that reason, the major focus of the present paper is to report on the latest developments for the determination of major ergot alkaloids and their epimers in cereals and cereal-derived products. Information about the stability and the availability of calibrants, sampling issues, extraction and clean-up strategies, and a variety of final separation and detection techniques is provided. The recently developed liquid chromatography-tandem mass spectrometric methods (LC-MS/MS) for the simultaneous quantification and identification of ergot alkaloids are given special consideration.

Degradation of Fluorescent Whitening Agents in Sunlit Natural Waters

Abstract: Stilbene-type fluorescent whitening agents (FWAs), such as the distyryl biphenyl (DSBP) and the diaminostilbene types (DAS 1 and DAS 2), are commonly used in detergents and papers. They are not readily biodegradable, but due to their ability to absorb part of the terrestial sunlight, they can be photochemically degraded in natural surface waters. Following a fast preceding photoisomerization, the three compounds are degraded by direct photochemical processes yielding mainly aldehydes and alcohols. Their degradation quantum yields are similar, about 10-4. Nevertheless, in samples of a eutrophic Swiss lake water, DSBP is photochemically degraded three times faster (t1/2 = 87 min) in summer noon terrestrial sunlight at 25 °C than DAS 1 and DAS 2 (t1/2 = 278 and 313 min) because of a higher rate of sunlight absorption by the DSBP isomer mixture. All FWAs are degraded faster if the oxygen concentration is increased. Dissolved natural organic material partly inhibits the degradation of DSBP in the reaction with...