Two new ent-3,4-seco-labdane diterpenoids from Callicarpa nudiflora

Abstract

Two new ent-3,4-seco-labdane diterpenoids, methylcallicarpate (1) and callicarpic acid (2), were isolated from the leaves of Callicarpa nudiflora Hook et Arn. Their structures and relative configurations were established by analysis of spectroscopic data. Their absolute configurations were assigned by the application of the CD technique for the first time among the ent-3,4-seco-labdane-type diterpenes.