7-O-6'-O-malonylcachinesidic acid, a new macrocyclic iridoid ester of malonic acid from the Tunisian plant Ajuga pseudoiva

A new iridoid glucoside, 7-O-6'-O-malonylcachinesidic acid (1), was isolated from the leaves of Ajuga pseudoiva and characterized as its triacetyl derivative (1a). Its structure was established by spectroscopic methods and showed an unusual feature, in which an alcoholic function of the iridoid moiety and the primary alcohol of a glucopyranose unit form a 13-membered heterocycle with malonic acid.