Anti-Cancer Effect of Sesquiterpene and Triterpenoids from Agarwood of Aquilaria sinensis

Two new guaiane sesquiterpenes, aquisinenoids A and B (1 and 2), two new eudesmane-type sesquiterpenoids, aquisinenoids C and D (3 and 4), one new cucurbitacin, aquisinenoid E (5), and five known cucurbitacins (6–10) were isolated from agarwood of Aquilaria sinensis. The structures of these new compounds, including their absolute configurations, were characterized by spectroscopic and computational methods. The biological evaluation showed that compounds 3 and 9 had an anti-cancer effect on most of the cancer cells at 5 μM, especially in human breast cancer cells. Interestingly, the new compound 3 exhibited more sensitivity on cancer cells than normal cells, highlighting its potential as a novel anti-cancer agent. Mechanically, compound 3 treatment increased the ROS generation and triggered apoptosis of human breast cancer cells.