Comparative GC/MS-profiling of triterpenes and stilbenes from three West African Combretum Species

Combretum species are widely used medicinal plants in Africa and Asia for many medicinal purposes. Several phytochemical investigations of the genus focus mainly on pentacyclic triterpenoids [1,2] and various polyphenols like flavonoids and stilbenoids [3]. In spite of all the earlier work done, there is still lack of data on the chemistry of some of the West African species like C. aculeatum, C. glutinosum and C. micranthum. Herein, we present a preliminary comparative profiling of triterpenoids and stilbenoids from the dichloromethane fractions of leaf and stem bark of C. aculeatum, C. glutinosum and C. micranthum using GC-MS. The terpenoids and stilbenoids were identified by comparing their mass spectrum to those of ursolic acid and combretastatin A4, respectively.

Fig.1: GC/MS profil of triterpenes and stilbenes from C. glutinosum and C. micranthum.

Ursolic acid was identified in the leaf extracts of all the three species whereas combretastatin A4 was found in small amounts only in the bark extract of C. glutinosum. The chromatograms showed high variations between species and also between the two studied organs (leaf and bark). Triterpenes were mainly observed in the leaf extracts, while stilbenes were more concentrated in the bark extracts. The final results of this study will contribute to the selection of highly active species for medicinal uses and to their authentication.

References: 1. Simon, G. (2003) Fitoterapia. 74: 339–344.

2. Litaudon, M. et al. (2009)J. Nat. Prod. 72: 1314–1320.

3. Pettit, G. R. et al. (1995)J. Med. Chem. 38: 1666–1672.