Synthesis and biological evaluation of new pyrazole carbohydrazides as antiproliferative and antioxidant agents.

5-Amino pyrazole carbohydrazides showed promising antioxidant activity, inhibiting reactive oxygen species (ROS) elevation in neutrophils. In previous structure-activity relationship (SAR) studies the free ammino group proved to be an important structural determinant for activity. In order to further extend the SARs of this class of compounds, the synthesis of novel benzylidene pyrazole carbohydrazides was carried out. The new derivatives share with the parent compounds the free amino group but bear an additional N-phenyl substituent on the pyrazole scaffold. Furthermore, different regioisomers were prepared to evaluate the effect of the pyrazole N-substitution on activity. The antiproliferative activity of these compounds was preliminarily tested in cell-based assay on a large panel of cancer cell lines. Additionally, the ability of the prepared derivatives to inhibit ROS formation and aggregation was tested on human platelets.