Evaluation of some 1H-pyrazole derivatives as a dual acting antimalarial and anti-leishmanial agents

The synthesis of a novel series of 1H-pyrazole derivatives was achieved by condensation of pyrazole aldehyde 1 with hydrazine hydrate to give hydrazone 7. On the other hand, cyclization of α,β-unsaturated ketone counterpart 2 using hydrazine hydrate in liquid aliphatic acids rendered compounds 4-6 and hydrazine hydrate in ethanol afforded compound 3. The later was allowed to react with aroyl chloride giving rise to compounds 8, 9. All compounds were tested for their in vivo anti-malarial and in vitro antileishmanial activities. The anti-malarial activity was performed using Plasmodium berghei infected mice, while the anti-leishmanial activity of the compounds was determined against Leishmania aethiopica promastigotes using alamar blue reduction assay. Compound 3, 1-(4-methylphenyl)-3-phenyl-4-[3-(2-thienyl)-2-pyrazolin-5-yl]-1H-pyrazole, possessed the highest anti-malarial activity with suppression of 70.26%. The highest anti-leishmanial activity was exhibited by compound 2, 1-(4-methylphenyl)-3-phenyl-4-[1-(2-thienyl)-prop-2-en-1-one]-1H-pyrazole, with an IC50 of 0.079μg/ml. Hydrazone 7 showed appreciable dual anti-malarial (suppression = 62.30%) and anti-leishmanial activity (IC50 = 1.823μg/ml).