LAUSR

Five pairs of enantiomeric compounds (1a/1b-5a/5b) including seven undescribed compounds (1a/1b-3a/3b, 4b) along with two known ones (6 and 7) have been isolated from corn silk (Stigma maydis). Racemic mixtures of these enantiomers were separated by HPLC with different types of chiral columns. Their structures were elucidated based on comprehensive spectroscopic analyses together with quantum chemical calculations of 13C NMR data and electronic circular dichroism (ECD) curves. All the isolates were evaluated for their inhibition ability of self-induced Aβ1-42 aggregation. Among them, compounds 4a (88.36%), 4b (74.66%) and 7 (85.65%) showed stronger inhibitory activity than the positive control curcumin (61.90%). The different inhibition profiles of enantiomers 4a and 4b were explained by docking simulation studies.