2-(2-Phenylethyl)chromone Derivatives in Chinese Agarwood “Qi-Nan” from Aquilaria sinensis

Five new 2-(2-phenylethyl)chromone derivatives, qinanones A−E (1–5), together with eight known 2-(2-phenylethyl)chromone derivatives (6–13), were isolated from the Et₂O extract of high-quality Chinese agarwood “Qi-Nan” originating from Aquilaria sinensis. The structures of the new 2-(2-phenylethyl)chromones were elucidated by spectroscopic techniques (UV, IR, 1D and 2D NMR) and MS analyses. In the bioassay for acetylcholinesterase inhibitors, compounds 1–6, 10, and 12 exhibited weak inhibitory activities (inhibition percentage ranged from 10 % to 24 % at the concentration of 50 µg/mL). Compared with other agarwoods, “Qi-Nan” was different in containing 2-(2-phenylethyl)chromones with unsubstituted chromone rings.