Platelet-inhibitory phenolic constituents from the fruits of Daemonorops draco.

Eight previously undescribed phenolic compounds, dracoropins A - H (1-8), along with two known analogues (9 and 10) were isolated from the fruits of Daemonorops draco. Four pairs of isomers (1a/1b, 2a/2b, 3a/3b, and 4a/4b) were resolved by using chiral-phase HPLC separation. Their structures, including the absolute configurations of the resolved isomers, were elucidated by analysis of spectroscopic data (1D and 2D NMR, IR, and HRESIMS), single-crystal X-ray diffraction, and electronic circular dichroism (ECD) calculations. Compounds 1, 2, and 3 bear a rare 2-phenylbenzo[d]-1,3-dioxepine skeleton. All the isolates were evaluated for their inhibitory activity against ATP release in thrombin-activated platelets. Compounds 2b, 3a, and 6 could significantly inhibit ATP release in thrombin-activated platelets.