Ganxiterpene A: a new triterpenoid with cytotoxic activity from Salvia przewalskii Maxim.: structural elucidation and bioinspired semisynthesis

Ganxiterpene A (1), an undescribed seco-triterpene containing lactone structure was isolated from the root of Salvia przewalskii Maxim, as well as seven known terpenoids were identified as δ-amyrone (2), 12α-hydroxy-δ-lactone (3), olean-12-ene-3, 11-dione (4), taxodione (5), rosmariquinone (6), tanshinoneIIA (7), cryptotanshinone (8), respectively. The biomimetic synthesis of 1, featuring a mCPBA-mediated tandem reaction was accomplished starting from 2. Biologically, Compounds 1 showed significant cytotoxicity against A549, MCF-7 and HepG2 with IC50 values of 0.98 ± 0.18, 1.29 ± 0.58 μM, 1.94 ± 0.77 μM, respectively.