5-Arylidene-N,N-diethylthiobarbiturates 1-25 were evaluated for their potential against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes and displayed varying degree of inhibition. Based on the IC50 values, compound 6 (IC50 = 92.51 and#177; 0.01 and#181;M) was the only active compound against acetylcholinesterase, however this compound was also weakly active against butyrylcholinesterase with an IC50 value 124.76 and#177; 0.02 and#181;M. Six compounds 1, 6, 7, 16, 17, and 18 showed weak inhibition against BChE, among them compound 18 (IC50 = 82.25 and#177; 0.07and#181;M) showed good inhibition against BChE. Nevertheless, compounds 1, 7, 16, 17, and 18 were selectively active against BChE enzyme.

In this research work Semicarbazide, thiosemicarbazide derivatives 3 to 25 were synthesized by conventional methods with high percentage yield and reaction rate. 1H-NMR and EIMS spectroscopic techniques were used to elucidate the structure of the synthesized compounds. The effect of thiosemicarbazide and semicarbazide derivatives as an antioxidant agents were studied by DPPH free radical scavenging, ferric ion reducing, ferrous ion chelating assays. Higher DDPH radical scavenging activity exhibited by most of the compounds as compared to standard vitamin C. Excellent ferric ion reducing activity was indicated by compounds of theseriesas compared to standard vitamin C. However most of the compounds generally showed average ferrous ion chelating activity than standard EDTA.

Schiff bases gaining remarkable importance day by day in the current situation Schiff bases are found to be a valuable pharmacophore for the synthesis and development of various biologically active heterocyclic compounds. In recent past, we have reported various classes of compounds as enzyme inhibitors, in continuation; A series of 2-Mercaptobenzimidazole hydrazone derivatives (9-42) were synthesized through multistep reactions in high yields and evaluated for butyrylcholinesterase inhibition. In present study, 2-ethylthio benzimidazole was formed by the reaction of 2-Mercaptobenzimidazole with bromoethane. In the second step (2-(2-(ethylthio)benzimidazolyl)acetate) obtained by the reaction of 2-ethylthio benzimidazole with ethyl chloroacetate. In the third step, 2-(2-(ethylthio)benzimidazolyl)acetate was refluxed in methanol with hydrazine hydrate and get 2-((ethylthio)benzimidazolyl)acetohyrazide. In the last step, 2-((ethylthio)benzimidazolyl)acetohyrazide was reacted with different aldehydes in the presence of glacial acetic acid (catalyst) to get a series of 2-Mercaptobenzimidazole hydrazone derivatives. Product was characterized by 1H NMR and 13C NMR. These newly synthesized compounds showed varying degree of butyrylcholinesterase inhibition. Compound no. 15 with (IC50 = 25.10 and#177; 0.90 and#181;M) was found to be most active in the whole series. Similarly, compounds 42, 12, 40, 17, 22, 28 and 09 exhibited excellent activity with IC50 values are (IC50 = 25.36 and#177; 0.57 and#181;M, IC50 = 27.30 and#177; 0.52 and#181;M, IC50 = 34.31 and#177; 0.59 and#181;M, IC50 = 51.29 and#177; 0.64 and#181;M, IC50 = 54.52 and#177; 0.95 and#181;M, IC50 = 57.90 and#177; 0.45 and#181;M and IC50 = 60.93 and#177;0.67 and#181;M) respectively as compared to standard galantamine 18.13and#177;0.20 and#181;M. Molecular docking helped to find interactions between butyrylcholinesterase enzyme and test compounds. This study results that Schiff bases have been discovered a new class of butyrylcholinesterase inhibitors which have not been discovered earlier.

5-Arylidene-N,N-diethylthiobarbiturates 1-25 were evaluated for their potential against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes and displayed varying degree of inhibition. Based on the IC50 values, compound 6 (IC50 = 92.51 and#177; 0.01 and#181;M) was the only active compound against acetylcholinesterase, however this compound was also weakly active against butyrylcholinesterase with an IC50 value 124.76 and#177; 0.02 and#181;M. Six compounds 1, 6, 7, 16, 17, and 18 showed weak inhibition against BChE, among them compound 18 (IC50 = 82.25 and#177; 0.07and#181;M) showed good inhibition against BChE. Nevertheless, compounds 1, 7, 16, 17, and 18 were selectively active against BChE enzyme.

In this research work Semicarbazide, thiosemicarbazide derivatives 3 to 25 were synthesized by conventional methods with high percentage yield and reaction rate. 1H-NMR and EIMS spectroscopic techniques were used to elucidate the structure of the synthesized compounds. The effect of thiosemicarbazide and semicarbazide derivatives as an antioxidant agents were studied by DPPH free radical scavenging, ferric ion reducing, ferrous ion chelating assays. Higher DDPH radical scavenging activity exhibited by most of the compounds as compared to standard vitamin C. Excellent ferric ion reducing activity was indicated by compounds of theseriesas compared to standard vitamin C. However most of the compounds generally showed average ferrous ion chelating activity than standard EDTA.