Concentration-dependent inhibition and selectivity profile of NCEs. (A) Concentration-dependent inhibition of caspase-3 with NCEs measured in presence of substrate (AC-DEVD-AMC) at 10 μM. The percentage of inhibition was calculated relative to the enzyme activity with no inhibitor present. (B) Selectivity profile of 3D using Biomol kit (Enzo Life Sciences, Inc.). The enzyme activities were monitored (ex/em 355/460) as a time-course measurement of the increase in fluorescence signal from fluorescently labeled peptide substrate for 120 min at room temperature.