SQUARROSIDE-A, A BIOLOGICALLY-ACTIVE TRITERPENE SAPONIN FROM ACANTHOPHYLLUM-SQUARROSUM

A new bioactive saponin has been isolated from the roots of Acanthophy llum squarrosum. Based on spectroscopic data, especially direct and lo ng-range heteronuclear 2D NMR analysis, and on chemical transformation s, the structure of this new compound was elucidated as 3-O-beta-D-gal actopyranosyl-(1 --> 2)-[beta-D-xylopyranosyl-(1 --> 3)]-beta-D-glucur onopyranosyl gypsogenin 28-O-beta-D-xylopyranosyl-(1 --> 4)-alpha-L-rh amnopyranosyl-(1 --> 2)-[alpha-L-arabinofuranosyl-(1 --> 3)]-beta-D-4- O-acetylfucopyranoside for which we proposed the name squarroside A. T his molecule showed a concentration dependent immunomodulatory effect in the in vitro lymphocyte transformation test.