Diterpenoids with anti-inflammatory activity from the lateral root of Aconitum carmichaelii debeaux

Five undescribed diterpenoids, including two ent-cleistanthane-type diterpenoids aconicleistanthanes A and B, a hetisine-type diterpenoid aconihetisine A, two aconitines-type diterpenoids aconicarmines A and B, and thirteen known diterpenoids alkaloids, were co-isolated from the lateral root of the Aconitum carmichaelii Debeaux (Ranunculaceae). Their structures were elucidated based on spectroscopic methods, and the absolute configu-rations were determined by X-ray diffraction and electronic circular dichroism (ECD) calculations. Among them, aconicleistanthanes A and B as ent-cleistanthane-type diterpenoid featuring a unique five-membered lactone D ring, is the first reported example of ent-cleistanthane-type diterpenoids in the Aconitum, which provided a new type of diterpene metabolites for Aconitum and enriched the chemical space of the plant of the Aconitum. In the bioassays, aconicleistanthane A significantly suppressed the production of pro-inflammatory mediators (IL-6, IL-1 beta and COX-2) and the protein expression of the enzyme iNOS at the concentration of 6.25 mu M.

Automated summary

Five undescribed diterpenoids and thirteen known diterpenoid alkaloids were isolated from the lateral root of Aconitum carmichaelii Debeaux. Aconicleistanthane A, one of the isolated compounds, exhibited significant anti-inflammatory activity.