SAPONINS FROM STEM BARK OF PETERSIANTHUS MACROCARPUS

Article abstract of DOI:10.1016/0031-9422(92)83729-I

Two bioactive saponins were isolated from the stem bark of Petersianthus macrocarpus.Their structures were elucidated by chemical degradations and by a combination of 2D NMR techniques and by Californium plasma desorption mass spectrometry.They are 3-O-<<β-D-galactopyranosyl (1->2)><β-D-galactopyranosyl (1->3)>-β-D-glucuronopyranosyl>-21-O-<3-(3-tigloyloxynilic acid)-4-tigloyloxy-α-L-arabinopyranosyl> barringtogenol C and 3-O-<<β-D-galactopyranosyl (1->2)><β-D-galactopyranosyl (1->3)>-β-D-glucuronopyranosyl>-28-O-α-L-rhamnopyranosyl barringtogenol C-21-O-benzoate.The absolute configuration of nilic acid was determined by partial synthesis. 3,3'-Dimethoxy ellagic acid and 3,3'-dimethoxy-4-O-β-D-glucopyranosyl ellagic acid were also isolated.Key Word Index: Petersianthus macrocarpus; Lecythidaceae; bark; saponins; nilic acid; ellagic acid.