Platelet-activating factor (PAF) receptor binding antagonists from Alpinia officinarum

Abstract The bioassay-guided purification of ether extracts of Alpinia officinarum led to the isolation of two new compounds 6-hydroxy-1,7-diphenyl-4-en-3-heptanone ( 1 ) and 6-(2-hydroxy-phenyl)-4-methoxy-2-pyrone ( 4 ) as well as three known compounds 1,7-diphenyl-4-en-3-heptanone ( 2 ), 1,7-diphenyl-5-methoxy-3-heptanone ( 3 ), and apigenin ( 5 ). Their structures were established on the basis of spectral methods. All three diarylheptanoids 1 , 2 , and 3 exhibited potent PAF receptor binding inhibitory activities with an IC 50 of 1.3, 5.0, and 1.6 μM, respectively. These studies have identified diarylheptanoids as a novel class of potent PAF antagonists.