Abstract
Schiff bases of 4-amino-1,5-dimethyl-2-phenylpyrazolone (2-18) were synthesized by treating with different benzaldehyde derivatives and tested for in vitro antioxidant activity. Synthesized Schiff base derivatives (2-18) were characterized by various spectroscopic techniques. Compounds specially having hydroxyl substituents showed good DPPH radical scavenging activity having IC50 values between 15.16 and 48.26 mu M. Compounds 3-7 showed stronger potency than the standard (n-propyl gallate, IC50 = 30.27 +/- 0.25 mu M). However, in the superoxide anion radical assay, derivatives 2, 4, 5, 6 and 7 showed better potency than the standard (n-propyl gallate, IC50 = 106.34 +/- 1.60 mu M).