Oleanane-type glycosides isolated from the trunk barks of the Central African tree Millettia laurentii

Seven previously undescribed oleanane-type glycosides were isolated from the trunk barks of a Central African tree named Millettia laurentii De Wild (Fabaceae). After the extraction from the barks, the isolation and purification of these compounds were achieved using various solid/liquid chromatographic methods. Their structures were established mainly by 1D and 2D NMR (COSY, TOCSY, ROESY, HSQC, HMBC) and mass spectrometry (ESI-MS), as 3-O-β-D-glucuronopyranosyl-(1 → 2)-β-D-glucuronopyranosylechinocystic acid, 3-O-β-D-apiofuranosyl-(1 → 3)-β-D-glucuronopyranosyl-(1 → 2)-β-D-glucuronopyranosylechinocystic acid, 3-O-β-D-apiofuranosyl-(1 → 3)-β-D-galactopyranosyl-(1 → 2)-β-D-glucuronopyranosylechinocystic acid, 3-O-β-D-apiofuranosyl-(1 → 3)-[β-D-xylopyranosyl-(1 → 2)]-β-D-galactopyranosyl-(1 → 2)-β-D-glucuronopyranosylechinocystic acid, 3-O-β-D-apiofuranosyl-(1 → 3)-[α-L-arabinofuranosyl-(1 → 2)]-β-D-galactopyranosyl-(1 → 2)-β-D-glucuronopyranosylechinocystic acid, 3-O-α-L-arabinofuranosyl-(1 → 2)-β-D-galactopyranosyl-(1 → 2)-β-D-glucuronopyranosyloleanolic acid, 3-O-β-D-apiofuranosyl-(1 → 3)-[α-L-arabinofuranosyl-(1 → 2)]-β-D-galactopyranosyl-(1 → 2)-β-D-glucuronopyranosyloleanolic acid. In addition, the cytotoxicity of six glycosides among the isolated ones, was evaluated against 4 T1 cell line from a mouse mammary gland tissue, using MTS method.