Bioactive ent-Clerodane Diterpenoids from the Aerial Parts of Baccharis gaudichaudiana

Abstract

Three new ent-clerodane diterpenes (1-3) were isolated from the aerial parts of Baccharis gaudichaudiana, and their structures were elucidated as 15,16-epoxy-15alpha-methoxy-ent-clerod-3-en-18-oic acid (1), 13-epi-15,16-epoxy-15alpha-methoxy-ent-clerod-3-en-18-oic acid (2), and 7-oxo-16-hydroxy-ent-clerod-3-en-15-oic acid methyl ester-18,19-olide (3), on the basis of spectroscopic data analysis. A known compound, 7-oxo-ent-clerod-3-en-15,16:18,19-diolide, was also identified. Compounds 1 and 2 showed enhancing activity of nerve growth factor (NGF)-induced neurite outgrowth in PC 12D cells.