Structure-activity relationship of chalcones and related derivatives as ligands for detecting of β-amyloid plaques in the brain

A series of novel chalcones and their related derivatives were synthesized and evaluated as beta-amyloid imaging probes. In the structure-activity relationship of binding affinities to synthetic A beta(1-42) aggregates, compound 14 displayed the highest binding affinity in vitro. Amyloid plaques in the Alzheimer's model mouse brain were visualized with 14. In biodistribution studies using normal mice, [I-125]14 showed good brain uptake (2.56% ID/g, 2 min postinjection) and rapid washout from the brain (0.21% ID/g, 60 min postinjection). These results suggest that [I-125]14 should be further investigated as a potentially useful P-amyloid imaging probe.