Two novel diterpenoids, jatrocurcadiones A (1) and B (2), possessing an unusual 10,11-seco-premyrsinane skeleton were isolated from the twigs of Jatropha curcas. Their structures were determined by combined spectroscopic and chemical methods, and the absolute configurations were elucidated by quantum chemical calculations and Rh2(OCOCF3)4-induced CD analysis. Jatrocurcadione A exhibited more potent inhibitory activity (IC50 = 10.0 μM) than the positive control (curcumin, IC50 = 25.0 μM) against thioredoxin reductase (TrxR), a potential target for cancer chemotherapy with redox balance and antioxidant functions.
