Six New neo-Clerodane Diterpenoids from Aerial Parts of Scutellaria barbata and Their Cytotoxic Activities.

Six new neo-clerodane diterpenoids (1-6), scutebatas X-Z, A1-C1, along with twelve known ones (7-18) were obtained via the phytochemical investigation of the aerial parts of Scutellaria barbata. Their structures were established by detailed spectroscopic analysis. The absolute configurations of 1 and 2, as the representative members of this type, were identified based on a circular dichroic exciton chirality method. Moreover, in vitro cytotoxicity of compounds 1-6 were evaluated against three human cancer cell lines (SGC-7901, MCF-7, and A-549) using the MTT method. Compound 6 showed cytotoxic activities against all the three cell lines with IC50 values of 17.9, 29.9, and 35.7 µM, respectively. [ABSTRACT FROM AUTHOR]