Chemical and Structural Properties of the Inclusion Complex of Euplotin C with Heptakis(2,6-di-O-methyl)-β-cyclodextrin through NMR Spectroscopy, Electrospray Mass Spectrometry and Molecular Mechanics Investigations
✍ Scribed by Graziano Guella; Emanuela Callone; Ines Mancini; Gloria Uccello-Barretta; Federica Balzano; Fernando Dini
- Publisher
- John Wiley and Sons
- Year
- 2004
- Tongue
- English
- Weight
- 278 KB
- Volume
- 2004
- Category
- Article
- ISSN
- 1434-193X
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✦ Synopsis
Abstract
The inclusion complex of heptakis(2,6‐di‐O‐methyl)‐β‐cyclodextrin (DIMEB) with euplotin C (EC), a cytotoxic metabolite isolated from the protistan strains composing the marine ciliate Euplotes crassus, has been investigated by ^1^H NMR techniques, electrospray ionization mass spectrometry (ESI/MS) and molecular mechanics (MM) calculations. The results suggest that DIMEB preferentially includes the side chain of this sesquiterpenoid with the terminal methyl groups exposed at the narrower rim of the cyclodextrin (CD). The dihydropyranic ring of EC is also well enclosed in the host cavity, whereas the acetyl group and the ring protons at C‐4 and C‐5 lie outside the larger rim. A kinetic degradation study of EC and its inclusion complex (EC‐DIMEB) in aqueous solution has been performed by HPLC‐UV‐MS measurements obtaining structural data for the hydrolysis end‐products. A significant increase in the chemical stability of complexed EC compared with free EC has also been determined. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)