Oleanane-type glycosides from Pittosporum tenuifolium “variegatum” and P. tenuifolium “gold star”

Abstract The phytochemical study of two cultivars of Pittosporum tenuifolium Banks & Sol. ex Gaertn, “variegatum” and “gold star”, led to the isolation of eight oleanane-type glycosides: seven previously undescribed and a known one. Their aglycons are oxygenated oleanane derivatives as barringtogenol C, camelliagenin A, hederagenin, and 22α-hydroxyoleanolic acid. Their structures were established by 2D NMR spectroscopic techniques and mass spectrometry as 3- O -β-D-galactopyranosyl-(1 → 2)-[α-L-arabinopyranosyl-(1 → 3)]-β-D-glucuronopyranosyl-21- O -angeloyl-22- O- acetylbarringtogenol C, 3- O -β-D-galactopyranosyl-(1 → 2)-[α-L-arabinopyranosyl-(1 → 3)]-β-D-glucuronopyranosyl-21,22-di- O- angeloylbarringtogenol C, 3- O -β-D-galactopyranosyl-(1 → 2)-[α-L-arabinopyranosyl-(1 → 3)]-β-D-glucuronopyranosyl-22- O -angeloylcamelliagenin A, 3- O -β-D-glucopyranosyl-(1 → 2)-[β-D-glucopyranosyl-(1 → 6)]-β-D-glucopyranosyl-22- O -[(6- O -acetyl)-β-D-glucopyranosyl]camelliagenin A, 3- O -β-D-galactopyranosyl-(1 → 2)-[α-L-arabinofuranosyl-(1 → 4)]-β-D-glucuronopyranosylhederagenin 28- O -β-D-glucopyranosyl ester, 3- O -α-L-arabinofuranosyl-(1 → 4)-β-D-glucuronopyranosylhederagenin 28- O -β-D-glucopyranosyl ester, 3- O -β-D-galactopyranosyl-(1 → 2)-[α-L-arabinofuranosyl-(1 → 4)]-β-D-glucuronopyranosyl-22α-hydroxyoleanolic acid 28- O -β-D-glucopyranosyl ester, and the known ilexoside XLIX. These results represent a significative contribution to the chemotaxonomy of the genus Pittosporum , highlighting hederagenin-type saponins as chemotaxonomic markers of P. tenuifolium cultivars.