Discovery of Isatin-Based Carbohydrazones as Potential Dual Inhibitors of Fatty Acid Amide Hydrolase and Monoacylglycerol Lipase

Using ligand-based design strategy, a set of isatin-3-carbohydrazones was designed, synthesized and evaluated for dual fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL) inhibition properties. Compound 5-chloro-N '-(5-chloro-2-oxoindolin-3-ylidene)-2-hydroxybenzohydrazide (13 b) emerged as a potent MAGL inhibitor with nanomolar activity (IC50=3.33 nM), while compound 5-chloro-N '-(1-(4-fluorobenzyl)-2-oxoindolin-3-ylidene)-2-hydroxybenzohydrazide (13 j) was the most potent selective FAAH inhibitor (IC50=37 nM). Compound 5-chloro-N '-(6-chloro-2-oxoindolin-3-ylidene)-2-hydroxybenzohydrazide (13 c) showed dual FAAH-MAGL inhibitory activity with an IC50 of 31 and 29 nM respectively. Enzyme kinetics studies revealed that the isatin-based carbohydrazones are reversible inhibitors for both FAAH and MAGL. Further, blood-brain permeability assay confirmed that the lead compounds (13 b, 13 c, 13 g, 13 m and 13 q) are suitable as CNS candidates. Molecular dynamics simulation studies revealed the putative binding modes and key interactions of lead inhibitors within the enzyme active sites. The lead dual FAAH-MAGL inhibitor 13 c showed significant antioxidant activity and neuroprotection in the cell-based cytotoxicity assay. In summary, the study yielded three potent FAAH/MAGL inhibitor compounds (13 b, 13 c and 13 j) with acceptable pharmacokinetic profile and thus can be considered as promising candidates for treating neurological and mood disorders.

Automated summary

By utilizing a ligand-based design strategy, a series of isatin-3-carbohydrazones were synthesized and evaluated for their dual FAAH and MAGL inhibition properties. The study identified potent inhibitors, with compounds 13b and 13j being the most effective against MAGL and FAAH respectively, while compound 13c exhibited dual inhibitory activity and significant antioxidant properties in cell-based assays. These compounds showed promising pharmacokinetic profiles for treating neurological and mood disorders.