3 ACYLATED SAPONINS AND A RELATED COMPOUND FROM PITHECELLOBIUM-DULCE

Four new oleanane-type triterpene glycosides, pithedulosides H-K (1-4) , were isolated from the seeds of Pithecellobium dulce. Their structur es were established by extensive NMR experiments and chemical methods. Compounds 1-3 comprised acacic acid as the aglycon and either monoter pene carboxylic acid and its xyloside or monoterpene carboxylic acid a s the acyl moiety at C-21. The oligosaccharide moieties linked to C-3 and C-28 were determined as ta-D-glucopyranosyl-(1-->2)]-beta-D-glucop yranosyl and ha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl ester, respectively. Compound 4 was established as an echinocystic acid 3-O- glycoside having the same sugar sequences as 1-3. Also obtained in thi s investigation was the known compound 5, which was identified as echi nocystic acid -D-glucopyranosyl-(1-->2)]-beta-D-glucopyranoside.