SMP-028 is an inhibitor of neutral cholesterol esterase (CEase), with an IC50 of 1.01 μM.
SMP-028 potently and concentration-dependently inhibits neutral cholesterol esterase (CEase) with an IC50 value of 1.01 μM. On the other hand, inhibition of other steroidogenic enzymes by SMP-028 is weak with IC50 values>10 μM. In particular, SMP-028 does not inhibit acid CEase and only weakly reduces the activity of CYP11A1 (IC50 values>100 μM and 49.8 μM respectively) [1]. SMP-028 at 10 μM or less does not affect the viability of male adrenal cells, female adrenal cells, testicular cells, and ovarian cells. On the other hand, SMP-028 at concentrations higher than 30 μM significantly reduce the viability of male adrenal cells, female adrenal cells [2].
[1]. Nishizato Y, et al. Translational research into species differences of endocrine toxicity via steroidogenesis inhibition by SMP-028--for human safety in clinical study. Toxicol Appl Pharmacol. 2014 May 1;276(3):213-9. [2]. Nishizato Y, et al. Effect of SMP-028 on steroidogenesis in rats; mechanism of toxicological events on endocrine organs of rats. Toxicol In Vitro. 2014 Apr;28(3):397-402.