Diterpenoid Alkaloids from Aconitum soongaricum var. pubescens.

One new diterpenoid alkaloid, pubescensine (1), along with nine known diterpenoid alkaloids (2-10) were isolated from the roots of Aconitum soongaricum var. pubescens. Their structures were elucidated by spectroscopic analyses and comparison with previously reported data. All the compounds were evaluated for their antifeedant activities. The aconitine-type diterpenoid alkaloids (1-6) showed considerably potent antifeedant activity (EC50 < 1 mg/cm2), while the activities of napelline-type diterpenoid alkaloids (compds. 7, 9 and 10) were not significant (EC50 > 50 mg/cm2).