Novel Type Secoiridoid Glucosides, Hydrangenosides B, C and D from Hydrangea macrophylla

Abstract

Along with the known hydrangenoside A (4), new glucosides of the same series, hydrangenosides B (1), C (2) and D (3), have been isolated from Hydrangea macrophylla and their absolute structures have been established. These substances are considered to be formed by an aldol-type condensation of secologanin (5) with a shikimate-malonate derived moiety followed by decarboxylation. Hydrangenoside A (4) and B (1) are stereoisomers, while hydrangenoside C (2) and D (3) are their homologues containing one fewer acetate unit and also are stereoisomers.