Planta Med 2011; 77 - PA40
DOI: 10.1055/s-0031-1282236

Profiling of African Mimosaceae for the rapid identification of new triterpenoid electrophiles

O Noté 1, A Urbain 1, C Antheaume 2, A Lobstein 1
  • 1Pharmacognosy and Bioactive Natural Substances, UMR 7200, University of Strasbourg, Faculty of Pharmacy, 74 route du Rhin – BP 60024–67401 Illkirch, France
  • 2Service Commun d'Analyse, University of Strasbourg, Faculty of Pharmacy, 74 route du Rhin – BP 60024–67401 Illkirch, France

Avicins are complex triterpenoid saponins isolated from an Australian Mimosaceae (Leguminosae), Acacia victoriae Benth. They are based on an acacic acid core, substituted by two glycosidic units and by a specific side chain at C-21 containing two monoterpene carboxylic acids and a quinovose moiety, conferring thereof particular electrophilic properties [1].

Avicins exhibit potent proapoptotic and anti-inflammatory activities, selectively inhibit the growth of tumor cells and thus appear as a new potential class of anticancer natural substances [2, 3].

In order to discover new avicins analogues and to identify the pharmacophore responsible for the activity, different African Mimosaceae species, including Acacia, Albizia, and Entada genera, were selected to screen their saponins content.

Chemical profiling of saponin-enriched fractions, based on a LC-UV-MS/MS dereplication method and NMR experiments, has pointed out the presence of avicins analogues in the different studied species. Characteristic structural features of avicins consisting of an acacic acid aglycone, a tri- or tetra-saccharide moiety at C-28, a sugar residue at C-3, and the acylation of C-21 were highlighted by the developed method.

These findings confirmed that some Mimosaceae species represent an alternative source for the discovery of new avicin analogues [4]. The dereplication approach enabled to quickly identify the compounds of interest, and so to focus on their specific isolation and saving a considerable amount of time.

Structures of the isolated triterpenoids will be unambiguously elucidated on the basis of extensive analysis of NMR experiments and mass spectrometry, and further submitted to bioassays to study in depth their mechanism of action.

References: 1. Jayatilake GS et al. (2003)J Nat Prod 66: 779–83.

2. Haridas V et al. (2001) Proc Natl Acad Sci USA 98: 11557–11562.

3. Gaikwad A et al. (2005) Clin Cancer Res 11: 1953–1962

4. Noté O et al. (2011) Phytochem Rev, in press