Vescalagin, ein kristalliner Gerbstoff aus dem Holz der Edelkastanie (Custanea sativa) und der Eiche (Quercus sesseliflora), besitzt Struktur 1 und ist damit anomer zu Castalagin (2). Die Struktur 1 wird bewiesen durch Vergleich der NMR-Spektren von Vescalagin mit Castalagin bzw. ihren entsprechenden Pentadecamethyl-(1 a, 2a), Monoacetyl-pentadecamethyl-(1 b, 2b) und Hexadecaacetyl-Derivaten (1 c, 2c) sowie durch Spaltung von Pentadecamethylvescalagin (la) mit Methanol/Natriummethylat in (-)-2.3.4.2'.3'.4'-Hexamethoxy-diphensaure-(6.6')-dimethylester und Nonamethyl-neovescalin-methylester. Ein ebenfalls isoliertes Primarprodukt dieser Spaltungsreaktion wird als Pentadecamethyl-neovescalagin-methylester (4a) erkannt.
On Tanning Compounds jrom the Wood oj Chestnut and Oak, VZ1). The Structure oj VescaluginVescalagin, a crystalline tanning compound from the wood of chestnut (Castaneu sutiva) and oak (Quercus sesseliflora), has the structure 1 and is therefore anomeric with castalagin (2). This structure is proved by comparing NMR-structural analysis of 1 and 2, and of its comparable pentadecamethyl-(1 a, 2a), monoacetyl-pentadecamethyl-(1 b, 2b) and hexadecaacetyl derivatives (lc, 2c) furthermore by the cleavage of pentadecamethyl-vescalagin (1 a) with sodium methoxide/methanol solution to produce dimethyl (--)-2,3,4,2',3',4'hexamethoxy-6,6'-diphenate and the methyl ester of nonamethylneovescalin. A primary product from this cleavage reaction is isolated too and elucidated as the methyl ester of pentadecamethyl-neovescalagin (4 a).Vescalagin4) (l), ein kristalliner Gerbstoff aus dem Holz der Edelkastanie (Castanea sativa) und der Eiche (Quercus sesseliflora), besitzt nach Elementaranalyse und massenspektrometrischer Molekulargewichtsbestimmung des Pentadecamethyl-Derivats l a
Durch Chromatographie an Cellulosepulver gelang es, aus dem Gesamtgerbstoff des Edelkastanienholzes (Custanea sativa) und des Eichenholzes (Quercus sesselijlora) vier chemisch einheitliche Verbindungen abzutrennen, die als Castalagin, Vescalagin, Castalin und Vescalin bezeichnet werden. -Castalagin und Vescalagin sind kristallisiert und besitzen die gleiche Summenformel. Castalagin liefert bei der Hydrolyse Ellagsaure und Castalin, Vescalagin ergibt hierbei Ellagsaure und Vescalin. Auch Castalin ist kristallisiert und isomer mit Vescalin. Beim Erhitzen in waiBriger Losung wandeln sich Castalagin in Vescalagin und Castalin in Vescalin um.
Celiac Disease (CD) is one of the most common food intolerances. It comes along with serious damage of the mucosa in the small intestine and is caused by the storage proteins—termed “gluten”—of wheat, rye, barley and possibly oats. Sensitive individuals need to stick to a strict gluten-free diet. The gluten level in food products labeled as “gluten-free”, must not exceed 20 mg/kg. It is obvious that effective test methods are needed to accurately determine the gluten concentration in foods. The determination of the presence of gluten in foodstuffs is mainly done by means of an immunochemical method called ELISA (enzyme-linked immunosorbent assay). To check the suitability of a G12 antibody-based gluten detection kit for its use in official control systems a number of routine samples were tested in parallel with two different test kits, as would be done in a routine lab. The determination of the gluten content was performed on samples entering the official laboratory including samples from official control plans, commercially available and private samples to request gluten-free labels. The results obtained with the G12 antibody ELISA assay were comparable to the official R5 method. A validation of the two different methods was not part of this study.
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