ACACIA CONCINNA SAPONINS .2. STRUCTURES OF MONOTERPENOID GLYCOSIDES IN THE ALKALINE HYDROLYSATE OF THE SAPONIN FRACTION

From the AcOEt-soluble fraction of the alkaline hydrolyzate of the hig hly polar saponin fraction of pods of Acacia concinna, two monoterpene s, (2E)-2,6-dimethyl-6-hydroxy-2,7-octadienoic acid (menthiafolic acid , 1) and 6-hydroxy-2-hydroxymethyl-6-methyl-2,7-octadienoic acid (4), and their glycosides, (6R)- and (6S)-menthiafolic acid-6-O-beta-D-quin ovoside (2a and 2b) and (6R)- and (6S)-menthiafolic acid-6-O-beta-D-xy loside (3a and 3b), were isolated. A more polar fraction gave, after m ethylation with diazomethane, (6R)- and 6-hydroxy-2-hydroxymethyl-6-me thyl-2,7-octadienoic acid-6-O-beta-D-quinovoside as their methyl ester s (5a and 5b). Compounds 2a, 3a, 4, 5a, and 5b are new. The structures of the above compounds were determined mainly by the application of s pectroscopic methods.