The effect of some Thiosemicarbazide derivatives and their complexes on Human Serum Cholinestrase Activity

The inhibitory effect of some 1-phenyl-3-methyl-5-pyrazolone thiosemicarbazone and 1- phenyl-3- methyl-5-pyrazolone-4-phenyl thiosemicarbazone and their complexes with Cr(III),Mo(V) and W(VI) on the activity of human serum cholinesterase have been studied in vitro. Some of these compounds showed a remarkable activity even at low concentration . From the degree of inhibition obtained, the time of incubation and inhibitor concentration for the highest inhibition have been determined. The results obtained from (Linweaver –Burk) plot indicates that the inhibition is Non- Competitive. The inhibition percentages obtained confirmed that the complexes has a higher inhibition than ligands.