Pentacyclic triterpenoids with cytotoxic activity from the stems of Syzygium jambos (L.) Alston

Phytochemical investigation of the stems of Syzygium jambos (L.) Alston resulted in the isolation of five new pentacyclic triterpenoids, including three oleananes (1, 2, and 5) and two ursanes (3 and 4), along with 23 known compounds (6–28). Their structures were elucidated by comprehensive spectroscopic analysis and chemical methods. All isolated compounds were evaluated for their cytotoxic activities against two lung carcinoma cell lines, H1975 and HCC827. Among them, compounds 2, 7, 11, 13–16, 18, and 23 exhibited significant cytotoxic activities against H1975 and/or HCC827 cells, with IC50 values below 10 μM. Furthermore, the preliminary structure-activity relationships of these pentacyclic triterpenoids are also discussed. Five new pentacyclic triterpenoids including three oleananes (1, 2, and 5) and two ursanes (3 and 4), along with 23 known compounds (6–28), were isolated from the stems of Syzygium jambos (L.) Alston. Among them, compounds 2 and 16 with a trans-feruloyl group at OH-23 exhibited the most potent cytotoxic activity against H1975 and HCC827 cells. [Display omitted]