Dimeric 2-(2-phenylethyl)chromones from the agarwood of Aquilaria crassna in Laos.

Four new dimeric 2-(2-phenylethyl)chromones (1-4) were isolated from the agarwood of Aquilaria crassna in Laos. All structures were determined based on extensive spectroscopic methods including IR, UV, 1D and 2D NMR, ECD, and HRMS. The structures of compounds 1-3 were characterized by two C-O-C linkages between the two chromone moieties, while compound 4 featured one C-O-C linkage and one CC bond connecting with two chromone moieties. Compounds 1 and 3 showed weak cytotoxicity against human hepatocellular carcinoma BEL-7402 cell line with IC50 values of 44.68 and 42.10 μΜ.