Oleanane-type glycosides from Tremastelma palaestinum (L.) Janchen

Abstract

Three new oleanane-type glycosides, 1-3, were isolated from the whole plant of Tremastelma palaestinum (L.) Janchen, along with eight known triterpene glycosides. The structures of the new compounds were established as 3-O-[β-d-glucopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→3)-β-d-glucopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranosyl]hederagenin (1), 3-O-[β-d-glucopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→3)-β-d-glucopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranosyl]hederagenin 28-O-β-d-glucopyranosyl-(1→6)-β-d-glucopyranosyl ester (2), and 3-O-[α-l-rhamnopyranosyl-(1→3)-β-d-glucopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranosyl]oleanolic acid 28-O-β-d-glucopyranosyl-(1→6)-β-d-glucopyranosyl ester (3) by using 1D- and 2D-NMR techniques and mass spectrometry. This is the first report on the phytochemical investigation of a species belonging to Tremastelma genus.

Keywords: Glycosides; Oleananes; Saponins; Tremastelma palaestinum.