Four new cembranoids from the Chinese soft coral Sinularia sp. and their anti-Aβ aggregation activities.

Four new cembranoids (1-4) were isolated from the extracts of a soft coral collected from the sea area near Xisha Island, South China Sea. The structures of these compounds were determined mainly by spectroscopic analyses, with the absolute configuration of 1 being established by X-ray diffraction analysis. In bioassay, compounds 1 and 3 displayed moderate inhibitory activity against Aβ42 aggregation (20.6% and 37.2% inhibition at 10 μM). The binding mode of 1 with Aβ42 monomer was predicted by molecular docking. In addition, compounds 1 and 3 did not show cytotoxicity against human tumor cell lines (SH-SY5Y, MDA-MB-426, A549, Hep3B, and HT-29) at 100 μM. Taken together, these cembranoids as new anti-Aβ aggregation agents derived from Sinularia sp. provided a new chemical scaffold for anti-Alzhemer's disease drug discovery.