Characterization of three new triterpenoid saponins from Ardisia japonica

The isolation and characterization of three novel triterpene glycosides 1-3 from the medicinal plant Ardisia japonica (Myrsinaceae) are described. The compounds are characterized by a branched oligosaccharide chain, composed of four sugar units. The oligosaccharide structures were determined by 1H-1H correlation spectroscopy (COSY, HOHAHA, ROESY) and 1H-13C heteronuclear correlation (HETCOR) nmr experiments. The aglycone moieties are the oleane-type triterpenes cyclamiretin A for 1 and the new 13,28-epoxy-30,30-dimethoxyolean-3 beta, 16 alpha-diol and 3 beta, 16 alpha-dihydroxy-13,28-epoxyolean-29-oic acid for 2 and 3, respectively.