Novel Hydralazine Schiff Base Derivatives and Their Antimicrobial, Antioxidant and Antiplasmodial Properties

Two novel Schiff bases, 3-[1-(2-(phthalazin-1-yl)hydrazono)ethyl)-1,3-oxa- zinane (PHEO) and 2-[(2-(phthalazin-1-yl)hydrazono)methyl]phenol (PHMP), derived from hydralazine hydrochloride, an effective drug against hypertension, were synthesized and characterized by spectroscopic methods, Infrared (IR), Proton Nuclear Magnetic Resonance (1H NMR) and Carbon-13 Nuclear Magnetic Resonance (13C NMR). PHEO showed low antimicrobial activity against one bacterial strain with MIC value of 250 μg/ml while PHMP showed interesting activity against 4 bacterial strains with MIC of 31.25 - 250 μg/ml compared to the standard drug, amoxicillin. PHEO and PHMP showed higher reducing activity on ferric ions compared to Vitamin C. On lipid peroxidation, PHEO showed higher inhibition while PHMP showed lower inhibition compared to Vitamin C. Both compounds presented lower stimulating effect and lower catalase activity compared to the standard Vitamin C. PHEO and PHMP showed less than 80% inhibition in the preliminary antiplasmodial assay and so were not considered for the dose-response studies.