Design, synthesis, and biological evaluation of novel (1-thioxo-1,2,3,4-tetrahydro-β-carbolin-9-yl)acetic acids as selective inhibitors for AKR1B1

New substituted (1-thioxo-1,2,3,4-tetrahydro-β-carbolin-9-yl)acetic acids were designed as the inhibitor of AKR1B1 based upon the structure of rhetsinine, a minor alkaloidal component of Evodia rutaecarpa , and twenty derivatives were synthesized and evaluated. The most active compound of the series was (2-benzyl-6-methoxy-1-thioxo-1,2,3,4-tetrahydro-β-carbolin-9-yl)acetic acid ( 7m ), which showed comparable inhibitory activity for AKR1B1 (IC 50  = 0.15 μM) with clinically used epalrestat (IC 50  = 0.1 μM). In the view of activity and selectivity, the most potent compound was (2-benzyl-6-carboxy-1-thioxo-1,2,3,4-tetrahydro-β-carbolin-9-yl)acetic acid ( 7t ), which showed strong inhibitory effect (IC 50  = 0.17 μM) and very high selectivity for AKR1B1 against AKR1A1 (311:1) and AKR1B10 (253:1) compared with epalrestat.