New neo-clerodane diterpenoids from Scutellaria barbata with cytotoxic activities.

Two new neo-clerodane diterpenoids have been isolated from the whole plant of Scutellaria barbata D. Don, and their structures were established by detailed spectral analyses as scutehenanine H (1) and 6-(2,3-epoxy-2-isopropyl-n-propoxyl)barbatin C (2). In vitro, the isolated two new compounds showed significant cytotoxic activities against three human cancer lines, and gave IC(50) values in the range OF 2.0-4.2 μΜ.