A new triterpenoidal saponin from the bark of Guaiacum officinale L.

A new triterpenoidal saponin, akebonic acid-3-O-[alpha-L-rhamnopyranosyl-(1 ->3)-beta-D-glu-copyranosyl-(1-> 3)-alpha-L-rhamnopyranosyl-(1->2)-alpha-L- arabinopyranoside], named as guaianin Q (1), was isolated from the n-butano lic extract of the bark of Guaiacum officinale L. The structure of 1 was es tablished with the help of the comparative studies of 1D and 2D H-1-C-13 NM R methods, FABMS, alkaline and acid hydrolyses. In addition to 1, a number of known saponins were also isolated and reported from the same source.