Diterpenoids with thioredoxin reductase inhibitory activities from Jatropha multifida.

Chemical investigation of the Jatropha multifida has led to the isolation of nine diterpenoids (1-9), including a new jatromulone A, four podocarpane diterpenoids (2-5), two lathyrane-type diterpenoids (6 and 7) and two dinorditerpenoids (8 and 9). Their structures were elucidated by spectroscopic analysis, and the absolute configurations of 1 were determined by CD analysis. All of the diterpenoids were screened for inhibitory activity against thioredoxin reductase (TrxR), which is a potential target for cancer chemotherapy with redox balance and antioxidant functions. Compounds 6 and 7 exhibited stronger activity (IC50 : 23.4 and 10.6 μM, respectively) than the positive control, curcumin (IC50  = 25.0 μM). Compounds 2-9 were isolated from J. multifida for the first time.