Serruloside and Serrulatoside, two New Iridoid Glycosides from Penstemon serrulatus1

From leaves of PENSTEMON SERRULATUS Menz. two new iridoid glycosides have been isolated. Both glycosides have the same aglycon part, but differ in their carbohydrate moieties. The structure of serru-loside (penstemidaglucon-11- O-beta- D-ribohexos -3-uloside) and serrulatoside (penstemidaglucon-ll- O-beta-4'-desoxyaltropyranosido-6'- O-beta- D-glucopyranoside) was established by spectroscopic methods (mainly (1)H- and (13)C-NMR) and comparison with known compounds.