Free and esterified 7-hydroxyaloins A and B are the most characteristic 10-C-glucosylanthrones in official Curacao aloes. These are responsible for a violet-purple colour in various pharmacopoeial identification and purity tests (e.g. Ph.Eur., USP); for a review see (1).
Almost 140 years after the first isolation of the principal component aloin of the world‐wide used drug Aloe barbadensis and Aloe capensis, the absolute configuration of aloin B (I) and aloin A (II) at C‐10 can now be established by an X‐ray analysis of (I).
Ellagi-and Gallotannins from Punica granatum Heartwood-[isolation and identification of the new ellagic acid derivatives (I) along with eight known ellagitannins and gallotannins]. -(EL-TOUMY, S. A. A.; MARZOUK, M. S.; RAUWALD, H. W.; Pharmazie 56 (2001) 10, 823-824;
Eine umfassende Analyse der 1H‐NMR Spektren der Aloine “A” und “B” ergibt keine signifikanten Unterschiede in den chemischen Verschiebungen und Kopplungskonstanten zwischen beiden Diastereomeren des 10‐Glucosylanthrontyps. Lediglich die Signale der 2′‐Hydroxylprotonen sind leicht zu unterscheiden. Die Signale der anomeren Protonen erscheinen im gleichen Bereich wie die anderen Ringprotonen des Zuckers und konnten nur durch Anwendung der NMR Doppelresonanztechnik identifiziert werden. Die zweifelsfreie Zuordnung ermöglicht eine einfache spektroskopische Bestimmung der β‐Konfiguration der Glucosylreste in beiden Aloinen.
The structure of 2-methoxystypandrone, a new naphthoquinone from the stem bark of Rhamnus fallax B., was elucidated by UV, IR, 1H-NMR, 13C-NMR, MS and chemical degradation as 6-Acetyl-5-hydroxy-2-methoxy-7-methyl-1,4-naphthoquinone. This is the first described occurrence of a naphthoquinone in a Rhamnus species. Free alaternin, 2-hydroxyemodin, was found for the second time in plant material.
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