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Keywords:

  • structure elucidation;
  • 4,4-dimethyl-2-vinylcyclohexene;
  • endo-5-methoxy-3-patchoulene;
  • root bark oil;
  • Annonaceae;
  • Xylopia aethiopica

ABSTRACT

Introduction

In the course of on-going work on the characterisation of aromatic plants from the Ivory Coast we investigated the composition of the root oil from Xylopia aethiopica.

Objectives

The aim of this work was to investigate the chemical composition of X. aethiopica root oil and elucidate the structure of two new compounds.

Methodology

Analysis of the essential oil was carried out using a combination of chromatographic (CC, GC with retention indices) and spectroscopic techniques (MS, 13C-NMR, 2D-NMR).

Results

Twenty seven components, accounting for 95.6% of the whole composition, were identified including various compounds for which spectroscopic data were absent on commercial computerised MS libraries. Three compounds are reported for the first time as natural compounds and the structure of two new compounds, 4,4-dimethyl-2-vinylcyclohexene and endo-5-methoxy-3-patchoulene, has been elucidated using extensive two-dimensional NMR spectroscopy.

Conclusion

The composition of X. aethiopica root oil is dominated by two dimethylvinylcyclohexene isomers. It differs drastically from the composition of leaf and fruit oils of the same plant. The combination of analytical techniques appeared crucial for a fruitful analysis. Copyright © 2012 John Wiley & Sons, Ltd.