In the present study, we used a comprehensive cellular toxicity (CeeTox) analysis panel to determine the toxicity profile for
CNB-001 [4-((1E)-2-(5-(4-hydroxy-3-methoxystyryl-)-1-phenyl-1H-pyrazoyl-3-yl)vinyl)-2-methoxy-
phenol)], which is a hybrid molecule created by combining cyclohexyl
bisphenol A, a molecule with neurotrophic activity and
curcumin, a spice with neuro-protective activity.
CNB-001 is a lead development compound since we have recently shown that
CNB-001 has significant preclinical efficacy both in vitro and in vivo. In this study, we compared the CeeTox profile of
CNB-001 with two neuroprotective molecules that have been clinically tested for efficacy: the hydrophilic
free radical spin trap agent
NXY-059 and the hydrophobic
free radical scavenger edaravone (Radicut). CeeTox analyses using a rat
hepatoma cell line (H4IIE) resulted in estimated C(Tox) value (i.e., sustained concentration expected to produce toxicity in a rat 14-day repeat dose study) of 42 μM for
CNB-001 compared with >300 μM for both
NXY-059 and Radicut. The CeeTox panel suggests that
CNB-001 produces some adverse effects on cellular
adenosine triphosphate content, membrane toxicity,
glutathione content, and cell mass (or number), but only with high concentrations of the
drug. After a 24-h exposure, the
drug concentration that produced a half-maximal response (TC(50)) on the measures noted above ranges from 55 to 193 μM. Moreover, all
CNB-001-induced changes in the markers were coincident with loss of cell number, prior to acute cell death as measured by membrane integrity, suggesting a
cytostatic effect of
CNB-001.
NXY-059 and Radicut did not have acute toxic effects on H4IIE cells. We also found that
CNB-001 resulted in an inhibition of
ethoxyresorufin-o-deethylase activity, indicating that the
drug may affect
cytochrome P4501A activity and that
CNB-001 was metabolically unstable using a rat microsome assay system. For
CNB-001, an estimated in vitro efficacy/toxicity ratio is 183-643-fold, suggesting that there is a significant therapeutic safety window for
CNB-001 and that it should be further developed as a novel
neuroprotective agent to treat
stroke.