Nine 2-(2-Phenylethyl)chromone Derivatives from the Resinous Wood of Aquilaria sinensis and Their Inhibition of LPS-Induced NO Production in RAW 264.7 Cells

A phytochemical investigation of aquilariae lignum resinatum, the resinous wood of Aquilaria sinensis (Lour.) Gilg, led to the isolation of nine new 2-(2-phenylethyl)chromone derivatives, aquilarones AI (19), together with two known analogues (10 and 11). Their structures were elucidated by extensive spectroscopic analyses, including UV, IR, NMR, and electronic circular dichroism (ECD) data, as well as by chemical methods. The absolute configuration of aquilarone A (1) was confirmed by single-crystal X-ray diffraction analysis of its acetonide derivative 1a. All the compounds exhibited significant inhibition of the nitric oxide production in RAW 264.7 cells, with IC50 values in the range of 5.1222.26 mu M. In addition, an HPLCUV comparison analysis of the resinous wood and resin-free wood is also included.